Effects of Continuous Kinaesthetic Feedback Based on Tendon Vibration on Motor Imagery BCI Performance.

PubMed

Barsotti, Michele; Leonardis, Daniele; Vanello, Nicola; Bergamasco, Massimo; Frisoli, Antonio

2018-01-01

Feedback plays a crucial role for using brain computer interface systems. This paper proposes the use of vibration-evoked kinaesthetic illusions as part of a novel multisensory feedback for a motor imagery (MI)-based BCI and investigates its contributions in terms of BCI performance and electroencephalographic (EEG) correlates. sixteen subjects performed two different right arm MI-BCI sessions: with the visual feedback only and with both visual and vibration-evoked kinaesthetic feedback, conveyed by the stimulation of the biceps brachi tendon. In both conditions, the sensory feedback was driven by the MI-BCI. The rich and more natural multisensory feedback was expected to facilitate the execution of MI, and thus to improve the performance of the BCI. The EEG correlates of the proposed feedback were also investigated with and without the performing of MI. the contribution of vibration-evoked kinaesthetic feedback led to statistically higher BCI performance (Anova, F (1,14) = 18.1, p < .01) and more stable EEG event-related-desynchronization. Obtained results suggest promising application of the proposed method in neuro-rehabilitation scenarios: the advantage of an improved usability could make the MI-BCIs more applicable for those patients having difficulties in performing kinaesthetic imagery.

Spontaneous eye movements in goldfish: oculomotor integrator performance, plasticity, and dependence on visual feedback.

PubMed

Mensh, B D; Aksay, E; Lee, D D; Seung, H S; Tank, D W

2004-03-01

To quantify performance of the goldfish oculomotor neural integrator and determine its dependence on visual feedback, we measured the relationship between eye drift-velocity and position during spontaneous gaze fixations in the light and in the dark. In the light, drift-velocities were typically less than 1 deg/s, similar to those observed in humans. During brief periods in darkness, drift-velocities were only slightly larger, but showed greater variance. One hour in darkness degraded fixation-holding performance. These findings suggest that while visual feedback is not essential for online fixation stability, it may be used to tune the mechanism of persistent neural activity in the oculomotor integrator.

Computerized visual feedback: an adjunct to robotic-assisted gait training.

PubMed

Banz, Raphael; Bolliger, Marc; Colombo, Gery; Dietz, Volker; Lünenburger, Lars

2008-10-01

Robotic devices for walking rehabilitation allow new possibilities for providing performance-related information to patients during gait training. Based on motor learning principles, augmented feedback during robotic-assisted gait training might improve the rehabilitation process used to regain walking function. This report presents a method to provide visual feedback implemented in a driven gait orthosis (DGO). The purpose of the study was to compare the immediate effect on motor output in subjects during robotic-assisted gait training when they used computerized visual feedback and when they followed verbal instructions of a physical therapist. Twelve people with neurological gait disorders due to incomplete spinal cord injury participated. Subjects were instructed to walk within the DGO in 2 different conditions. They were asked to increase their motor output by following the instructions of a therapist and by observing visual feedback. In addition, the subjects' opinions about using visual feedback were investigated by a questionnaire. Computerized visual feedback and verbal instructions by the therapist were observed to result in a similar change in motor output in subjects when walking within the DGO. Subjects reported that they were more motivated and concentrated on their movements when using computerized visual feedback compared with when no form of feedback was provided. Computerized visual feedback is a valuable adjunct to robotic-assisted gait training. It represents a relevant tool to increase patients' motor output, involvement, and motivation during gait training, similar to verbal instructions by a therapist.

Adaptive strategies of remote systems operators exposed to perturbed camera-viewing conditions

NASA Technical Reports Server (NTRS)

Stuart, Mark A.; Manahan, Meera K.; Bierschwale, John M.; Sampaio, Carlos E.; Legendre, A. J.

1991-01-01

This report describes a preliminary investigation of the use of perturbed visual feedback during the performance of simulated space-based remote manipulation tasks. The primary objective of this NASA evaluation was to determine to what extent operators exhibit adaptive strategies which allow them to perform these specific types of remote manipulation tasks more efficiently while exposed to perturbed visual feedback. A secondary objective of this evaluation was to establish a set of preliminary guidelines for enhancing remote manipulation performance and reducing the adverse effects. These objectives were accomplished by studying the remote manipulator performance of test subjects exposed to various perturbed camera-viewing conditions while performing a simulated space-based remote manipulation task. Statistical analysis of performance and subjective data revealed that remote manipulation performance was adversely affected by the use of perturbed visual feedback and performance tended to improve with successive trials in most perturbed viewing conditions.

Patient DF's visual brain in action: Visual feedforward control in visual form agnosia.

PubMed

Whitwell, Robert L; Milner, A David; Cavina-Pratesi, Cristiana; Barat, Masihullah; Goodale, Melvyn A

2015-05-01

Patient DF, who developed visual form agnosia following ventral-stream damage, is unable to discriminate the width of objects, performing at chance, for example, when asked to open her thumb and forefinger a matching amount. Remarkably, however, DF adjusts her hand aperture to accommodate the width of objects when reaching out to pick them up (grip scaling). While this spared ability to grasp objects is presumed to be mediated by visuomotor modules in her relatively intact dorsal stream, it is possible that it may rely abnormally on online visual or haptic feedback. We report here that DF's grip scaling remained intact when her vision was completely suppressed during grasp movements, and it still dissociated sharply from her poor perceptual estimates of target size. We then tested whether providing trial-by-trial haptic feedback after making such perceptual estimates might improve DF's performance, but found that they remained significantly impaired. In a final experiment, we re-examined whether DF's grip scaling depends on receiving veridical haptic feedback during grasping. In one condition, the haptic feedback was identical to the visual targets. In a second condition, the haptic feedback was of a constant intermediate width while the visual target varied trial by trial. Despite this incongruent feedback, DF still scaled her grip aperture to the visual widths of the target blocks, showing only normal adaptation to the false haptically-experienced width. Taken together, these results strengthen the view that DF's spared grasping relies on a normal mode of dorsal-stream functioning, based chiefly on visual feedforward processing. Copyright © 2014 Elsevier B.V. All rights reserved.

Bimanual Coordination Learning with Different Augmented Feedback Modalities and Information Types

PubMed Central

Chiou, Shiau-Chuen; Chang, Erik Chihhung

2016-01-01

Previous studies have shown that bimanual coordination learning is more resistant to the removal of augmented feedback when acquired with auditory than with visual channel. However, it is unclear whether this differential “guidance effect” between feedback modalities is due to enhanced sensorimotor integration via the non-dominant auditory channel or strengthened linkage to kinesthetic information under rhythmic input. The current study aimed to examine how modalities (visual vs. auditory) and information types (continuous visuospatial vs. discrete rhythmic) of concurrent augmented feedback influence bimanual coordination learning. Participants either learned a 90°-out-of-phase pattern for three consecutive days with Lissajous feedback indicating the integrated position of both arms, or with visual or auditory rhythmic feedback reflecting the relative timing of the movement. The results showed diverse performance change after practice when the feedback was removed between Lissajous and the other two rhythmic groups, indicating that the guidance effect may be modulated by the type of information provided during practice. Moreover, significant performance improvement in the dual-task condition where the irregular rhythm counting task was applied as a secondary task also suggested that lower involvement of conscious control may result in better performance in bimanual coordination. PMID:26895286

Bimanual Coordination Learning with Different Augmented Feedback Modalities and Information Types.

PubMed

Chiou, Shiau-Chuen; Chang, Erik Chihhung

2016-01-01

Previous studies have shown that bimanual coordination learning is more resistant to the removal of augmented feedback when acquired with auditory than with visual channel. However, it is unclear whether this differential "guidance effect" between feedback modalities is due to enhanced sensorimotor integration via the non-dominant auditory channel or strengthened linkage to kinesthetic information under rhythmic input. The current study aimed to examine how modalities (visual vs. auditory) and information types (continuous visuospatial vs. discrete rhythmic) of concurrent augmented feedback influence bimanual coordination learning. Participants either learned a 90°-out-of-phase pattern for three consecutive days with Lissajous feedback indicating the integrated position of both arms, or with visual or auditory rhythmic feedback reflecting the relative timing of the movement. The results showed diverse performance change after practice when the feedback was removed between Lissajous and the other two rhythmic groups, indicating that the guidance effect may be modulated by the type of information provided during practice. Moreover, significant performance improvement in the dual-task condition where the irregular rhythm counting task was applied as a secondary task also suggested that lower involvement of conscious control may result in better performance in bimanual coordination.

Modeling trial by trial and block feedback in perceptual learning

PubMed Central

Liu, Jiajuan; Dosher, Barbara; Lu, Zhong-Lin

2014-01-01

Feedback has been shown to play a complex role in visual perceptual learning. It is necessary for performance improvement in some conditions while not others. Different forms of feedback, such as trial-by-trial feedback or block feedback, may both facilitate learning, but with different mechanisms. False feedback can abolish learning. We account for all these results with the Augmented Hebbian Reweight Model (AHRM). Specifically, three major factors in the model advance performance improvement: the external trial-by-trial feedback when available, the self-generated output as an internal feedback when no external feedback is available, and the adaptive criterion control based on the block feedback. Through simulating a comprehensive feedback study (Herzog & Fahle 1997, Vision Research, 37 (15), 2133–2141), we show that the model predictions account for the pattern of learning in seven major feedback conditions. The AHRM can fully explain the complex empirical results on the role of feedback in visual perceptual learning. PMID:24423783

Multivariable manual control with simultaneous visual and auditory presentation of information. [for improved compensatory tracking performance of human operator

NASA Technical Reports Server (NTRS)

Uhlemann, H.; Geiser, G.

1975-01-01

Multivariable manual compensatory tracking experiments were carried out in order to determine typical strategies of the human operator and conditions for improvement of his performance if one of the visual displays of the tracking errors is supplemented by an auditory feedback. Because the tracking error of the system which is only visually displayed is found to decrease, but not in general that of the auditorally supported system, it was concluded that the auditory feedback unloads the visual system of the operator who can then concentrate on the remaining exclusively visual displays.

Memory-guided force control in healthy younger and older adults.

PubMed

Neely, Kristina A; Samimy, Shaadee; Blouch, Samantha L; Wang, Peiyuan; Chennavasin, Amanda; Diaz, Michele T; Dennis, Nancy A

2017-08-01

Successful performance of a memory-guided motor task requires participants to store and then recall an accurate representation of the motor goal. Further, participants must monitor motor output to make adjustments in the absence of visual feedback. The goal of this study was to examine memory-guided grip force in healthy younger and older adults and compare it to performance on behavioral tasks of working memory. Previous work demonstrates that healthy adults decrease force output as a function of time when visual feedback is not available. We hypothesized that older adults would decrease force output at a faster rate than younger adults, due to age-related deficits in working memory. Two groups of participants, younger adults (YA: N = 32, mean age 21.5 years) and older adults (OA: N = 33, mean age 69.3 years), completed four 20-s trials of isometric force with their index finger and thumb, equal to 25% of their maximum voluntary contraction. In the full-vision condition, visual feedback was available for the duration of the trial. In the no vision condition, visual feedback was removed for the last 12 s of each trial. Participants were asked to maintain constant force output in the absence of visual feedback. Participants also completed tasks of word recall and recognition and visuospatial working memory. Counter to our predictions, when visual feedback was removed, younger adults decreased force at a faster rate compared to older adults and the rate of decay was not associated with behavioral performance on tests of working memory.

Stimulus-dependent modulation of visual neglect in a touch-screen cancellation task.

PubMed

Keller, Ingo; Volkening, Katharina; Garbacenkaite, Ruta

2015-05-01

Patients with left-sided neglect frequently show omissions and repetitive behavior on cancellation tests. Using a touch-screen-based cancellation task, we tested how visual feedback and distracters influence the number of omissions and perseverations. Eighteen patients with left-sided visual neglect and 18 healthy controls performed four different cancellation tasks on an iPad touch screen: no feedback (the display did not change during the task), visual feedback (touched targets changed their color from black to green), visual feedback with distracters (20 distracters were evenly embedded in the display; detected targets changed their color from black to green), vanishing targets (touched targets disappeared from the screen). Except for the condition with vanishing targets, neglect patients had significantly more omissions and perseverations than healthy controls in the remaining three subtests. Both conditions providing feedback by changing the target color showed the highest number of omissions. Erasure of targets nearly diminished omissions completely. The highest rate of perseverations was observed in the no-feedback condition. The implementation of distracters led to a moderate number of perseverations. Visual feedback without distracters and vanishing targets abolished perseverations nearly completely. Visual feedback and the presence of distracters aggravated hemispatial neglect. This finding is compatible with impaired disengagement from the ipsilesional side as an important factor of visual neglect. Improvement of cancellation behavior with vanishing targets could have therapeutic implications. (c) 2015 APA, all rights reserved).

The Role of Direct and Visual Force Feedback in Suturing Using a 7-DOF Dual-Arm Teleoperated System.

PubMed

Talasaz, Ali; Trejos, Ana Luisa; Patel, Rajni V

2017-01-01

The lack of haptic feedback in robotics-assisted surgery can result in tissue damage or accidental tool-tissue hits. This paper focuses on exploring the effect of haptic feedback via direct force reflection and visual presentation of force magnitudes on performance during suturing in robotics-assisted minimally invasive surgery (RAMIS). For this purpose, a haptics-enabled dual-arm master-slave teleoperation system capable of measuring tool-tissue interaction forces in all seven Degrees-of-Freedom (DOFs) was used. Two suturing tasks, tissue puncturing and knot-tightening, were chosen to assess user skills when suturing on phantom tissue. Sixteen subjects participated in the trials and their performance was evaluated from various points of view: force consistency, number of accidental hits with tissue, amount of tissue damage, quality of the suture knot, and the time required to accomplish the task. According to the results, visual force feedback was not very useful during the tissue puncturing task as different users needed different amounts of force depending on the penetration of the needle into the tissue. Direct force feedback, however, was more useful for this task to apply less force and to minimize the amount of damage to the tissue. Statistical results also reveal that both visual and direct force feedback were required for effective knot tightening: direct force feedback could reduce the number of accidental hits with the tissue and also the amount of tissue damage, while visual force feedback could help to securely tighten the suture knots and maintain force consistency among different trials/users. These results provide evidence of the importance of 7-DOF force reflection when performing complex tasks in a RAMIS setting.

Mobile in vivo camera robots provide sole visual feedback for abdominal exploration and cholecystectomy.

PubMed

Rentschler, M E; Dumpert, J; Platt, S R; Ahmed, S I; Farritor, S M; Oleynikov, D

2006-01-01

The use of small incisions in laparoscopy reduces patient trauma, but also limits the surgeon's ability to view and touch the surgical environment directly. These limitations generally restrict the application of laparoscopy to procedures less complex than those performed during open surgery. Although current robot-assisted laparoscopy improves the surgeon's ability to manipulate and visualize the target organs, the instruments and cameras remain fundamentally constrained by the entry incisions. This limits tool tip orientation and optimal camera placement. The current work focuses on developing a new miniature mobile in vivo adjustable-focus camera robot to provide sole visual feedback to surgeons during laparoscopic surgery. A miniature mobile camera robot was inserted through a trocar into the insufflated abdominal cavity of an anesthetized pig. The mobile robot allowed the surgeon to explore the abdominal cavity remotely and view trocar and tool insertion and placement without entry incision constraints. The surgeon then performed a cholecystectomy using the robot camera alone for visual feedback. This successful trial has demonstrated that miniature in vivo mobile robots can provide surgeons with sufficient visual feedback to perform common procedures while reducing patient trauma.

Vibrotactile grasping force and hand aperture feedback for myoelectric forearm prosthesis users.

PubMed

Witteveen, Heidi J B; Rietman, Hans S; Veltink, Peter H

2015-06-01

User feedback about grasping force and hand aperture is very important in object handling with myoelectric forearm prostheses but is lacking in current prostheses. Vibrotactile feedback increases the performance of healthy subjects in virtual grasping tasks, but no extensive validation on potential users has been performed. Investigate the performance of upper-limb loss subjects in grasping tasks with vibrotactile stimulation, providing hand aperture, and grasping force feedback. Cross-over trial. A total of 10 subjects with upper-limb loss performed virtual grasping tasks while perceiving vibrotactile feedback. Hand aperture feedback was provided through an array of coin motors and grasping force feedback through a single miniature stimulator or an array of coin motors. Objects with varying sizes and weights had to be grasped by a virtual hand. Percentages correctly applied hand apertures and correct grasping force levels were all higher for the vibrotactile feedback condition compared to the no-feedback condition. With visual feedback, the results were always better compared to the vibrotactile feedback condition. Task durations were comparable for all feedback conditions. Vibrotactile grasping force and hand aperture feedback improves grasping performance of subjects with upper-limb loss. However, it should be investigated whether this is of additional value in daily-life tasks. This study is a first step toward the implementation of sensory vibrotactile feedback for users of myoelectric forearm prostheses. Grasping force feedback is crucial for optimal object handling, and hand aperture feedback is essential for reduction of required visual attention. Grasping performance with feedback is evaluated for the potential users. © The International Society for Prosthetics and Orthotics 2014.

Short Term Motor-Skill Acquisition Improves with Size of Self-Controlled Virtual Hands

PubMed Central

Ossmy, Ori; Mukamel, Roy

2017-01-01

Visual feedback in general, and from the body in particular, is known to influence the performance of motor skills in humans. However, it is unclear how the acquisition of motor skills depends on specific visual feedback parameters such as the size of performing effector. Here, 21 healthy subjects physically trained to perform sequences of finger movements with their right hand. Through the use of 3D Virtual Reality devices, visual feedback during training consisted of virtual hands presented on the screen, tracking subject’s hand movements in real time. Importantly, the setup allowed us to manipulate the size of the displayed virtual hands across experimental conditions. We found that performance gains increase with the size of virtual hands. In contrast, when subjects trained by mere observation (i.e., in the absence of physical movement), manipulating the size of the virtual hand did not significantly affect subsequent performance gains. These results demonstrate that when it comes to short-term motor skill learning, the size of visual feedback matters. Furthermore, these results suggest that highest performance gains in individual subjects are achieved when the size of the virtual hand matches their real hand size. These results may have implications for optimizing motor training schemes. PMID:28056023

Visual and somatic sensory feedback of brain activity for intuitive surgical robot manipulation.

PubMed

Miura, Satoshi; Matsumoto, Yuya; Kobayashi, Yo; Kawamura, Kazuya; Nakashima, Yasutaka; Fujie, Masakatsu G

2015-01-01

This paper presents a method to evaluate the hand-eye coordination of the master-slave surgical robot by measuring the activation of the intraparietal sulcus in users brain activity during controlling virtual manipulation. The objective is to examine the changes in activity of the intraparietal sulcus when the user's visual or somatic feedback is passed through or intercepted. The hypothesis is that the intraparietal sulcus activates significantly when both the visual and somatic sense pass feedback, but deactivates when either visual or somatic is intercepted. The brain activity of three subjects was measured by the functional near-infrared spectroscopic-topography brain imaging while they used a hand controller to move a virtual arm of a surgical simulator. The experiment was performed several times with three conditions: (i) the user controlled the virtual arm naturally under both visual and somatic feedback passed, (ii) the user moved with closed eyes under only somatic feedback passed, (iii) the user only gazed at the screen under only visual feedback passed. Brain activity showed significantly better control of the virtual arm naturally (p<;0.05) when compared with moving with closed eyes or only gazing among all participants. In conclusion, the brain can activate according to visual and somatic sensory feedback agreement.

Fitts' Law in the Control of Isometric Grip Force With Naturalistic Targets.

PubMed

Thumser, Zachary C; Slifkin, Andrew B; Beckler, Dylan T; Marasco, Paul D

2018-01-01

Fitts' law models the relationship between amplitude, precision, and speed of rapid movements. It is widely used to quantify performance in pointing tasks, study human-computer interaction, and generally to understand perceptual-motor information processes, including research to model performance in isometric force production tasks. Applying Fitts' law to an isometric grip force task would allow for quantifying grasp performance in rehabilitative medicine and may aid research on prosthetic control and design. We examined whether Fitts' law would hold when participants attempted to accurately produce their intended force output while grasping a manipulandum when presented with images of various everyday objects (we termed this the implicit task). Although our main interest was the implicit task, to benchmark it and establish validity, we examined performance against a more standard visual feedback condition via a digital force-feedback meter on a video monitor (explicit task). Next, we progressed from visual force feedback with force meter targets to the same targets without visual force feedback (operating largely on feedforward control with tactile feedback). This provided an opportunity to see if Fitts' law would hold without vision, and allowed us to progress toward the more naturalistic implicit task (which does not include visual feedback). Finally, we changed the nature of the targets from requiring explicit force values presented as arrows on a force-feedback meter (explicit targets) to the more naturalistic and intuitive target forces implied by images of objects (implicit targets). With visual force feedback the relation between task difficulty and the time to produce the target grip force was predicted by Fitts' law (average r 2 = 0.82). Without vision, average grip force scaled accurately although force variability was insensitive to the target presented. In contrast, images of everyday objects generated more reliable grip forces without the visualized force meter. In sum, population means were well-described by Fitts' law for explicit targets with vision ( r 2 = 0.96) and implicit targets ( r 2 = 0.89), but not as well-described for explicit targets without vision ( r 2 = 0.54). Implicit targets should provide a realistic see-object-squeeze-object test using Fitts' law to quantify the relative speed-accuracy relationship of any given grasper.

Effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability.

PubMed

Nam, Seung-Min; Kim, Kyoung; Lee, Do Youn

2018-01-01

[Purpose] This study examined the effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability. [Subjects and Methods] Twenty eight adults with functional ankle instability, divided randomly into an experimental group, which performed visual feedback balance training for 20 minutes and ankle joint exercises for 10 minutes, and a control group, which performed ankle joint exercise for 30 minutes. Exercises were completed three times a week for 8 weeks. Bio rescue was used for balance ability. It measured limit of stability at one minute. For ankle instability was measured using Cumberland ankle instability tool (CAIT). This measure was performed before and after the experiments in each group. [Results] The experimental group had significant increase in the Limit of Stability and CAIT score. The control group had significant increase in CAIT score. While the Limit of Stability increased without significance. [Conclusion] In conclusion, visual feedback balance training can be recommended as a treatment method for patients with functional ankle instability.

Good vibrations: tactile feedback in support of attention allocation and human-automation coordination in event-driven domains.

PubMed

Sklar, A E; Sarter, N B

1999-12-01

Observed breakdowns in human-machine communication can be explained, in part, by the nature of current automation feedback, which relies heavily on focal visual attention. Such feedback is not well suited for capturing attention in case of unexpected changes and events or for supporting the parallel processing of large amounts of data in complex domains. As suggested by multiple-resource theory, one possible solution to this problem is to distribute information across various sensory modalities. A simulator study was conducted to compare the effectiveness of visual, tactile, and redundant visual and tactile cues for indicating unexpected changes in the status of an automated cockpit system. Both tactile conditions resulted in higher detection rates for, and faster response times to, uncommanded mode transitions. Tactile feedback did not interfere with, nor was its effectiveness affected by, the performance of concurrent visual tasks. The observed improvement in task-sharing performance indicates that the introduction of tactile feedback is a promising avenue toward better supporting human-machine communication in event-driven, information-rich domains.

Brain-actuated gait trainer with visual and proprioceptive feedback

NASA Astrophysics Data System (ADS)

Liu, Dong; Chen, Weihai; Lee, Kyuhwa; Chavarriaga, Ricardo; Bouri, Mohamed; Pei, Zhongcai; Millán, José del R.

2017-10-01

Objective. Brain-machine interfaces (BMIs) have been proposed in closed-loop applications for neuromodulation and neurorehabilitation. This study describes the impact of different feedback modalities on the performance of an EEG-based BMI that decodes motor imagery (MI) of leg flexion and extension. Approach. We executed experiments in a lower-limb gait trainer (the legoPress) where nine able-bodied subjects participated in three consecutive sessions based on a crossover design. A random forest classifier was trained from the offline session and tested online with visual and proprioceptive feedback, respectively. Post-hoc classification was conducted to assess the impact of feedback modalities and learning effect (an improvement over time) on the simulated trial-based performance. Finally, we performed feature analysis to investigate the discriminant power and brain pattern modulations across the subjects. Main results. (i) For real-time classification, the average accuracy was 62.33 +/- 4.95 % and 63.89 +/- 6.41 % for the two online sessions. The results were significantly higher than chance level, demonstrating the feasibility to distinguish between MI of leg extension and flexion. (ii) For post-hoc classification, the performance with proprioceptive feedback (69.45 +/- 9.95 %) was significantly better than with visual feedback (62.89 +/- 9.20 %), while there was no significant learning effect. (iii) We reported individual discriminate features and brain patterns associated to each feedback modality, which exhibited differences between the two modalities although no general conclusion can be drawn. Significance. The study reported a closed-loop brain-controlled gait trainer, as a proof of concept for neurorehabilitation devices. We reported the feasibility of decoding lower-limb movement in an intuitive and natural way. As far as we know, this is the first online study discussing the role of feedback modalities in lower-limb MI decoding. Our results suggest that proprioceptive feedback has an advantage over visual feedback, which could be used to improve robot-assisted strategies for motor training and functional recovery.

Brain-actuated gait trainer with visual and proprioceptive feedback.

PubMed

Liu, Dong; Chen, Weihai; Lee, Kyuhwa; Chavarriaga, Ricardo; Bouri, Mohamed; Pei, Zhongcai; Del R Millán, José

2017-10-01

Brain-machine interfaces (BMIs) have been proposed in closed-loop applications for neuromodulation and neurorehabilitation. This study describes the impact of different feedback modalities on the performance of an EEG-based BMI that decodes motor imagery (MI) of leg flexion and extension. We executed experiments in a lower-limb gait trainer (the legoPress) where nine able-bodied subjects participated in three consecutive sessions based on a crossover design. A random forest classifier was trained from the offline session and tested online with visual and proprioceptive feedback, respectively. Post-hoc classification was conducted to assess the impact of feedback modalities and learning effect (an improvement over time) on the simulated trial-based performance. Finally, we performed feature analysis to investigate the discriminant power and brain pattern modulations across the subjects. (i) For real-time classification, the average accuracy was [Formula: see text]% and [Formula: see text]% for the two online sessions. The results were significantly higher than chance level, demonstrating the feasibility to distinguish between MI of leg extension and flexion. (ii) For post-hoc classification, the performance with proprioceptive feedback ([Formula: see text]%) was significantly better than with visual feedback ([Formula: see text]%), while there was no significant learning effect. (iii) We reported individual discriminate features and brain patterns associated to each feedback modality, which exhibited differences between the two modalities although no general conclusion can be drawn. The study reported a closed-loop brain-controlled gait trainer, as a proof of concept for neurorehabilitation devices. We reported the feasibility of decoding lower-limb movement in an intuitive and natural way. As far as we know, this is the first online study discussing the role of feedback modalities in lower-limb MI decoding. Our results suggest that proprioceptive feedback has an advantage over visual feedback, which could be used to improve robot-assisted strategies for motor training and functional recovery.

The integration of temporally shifted visual feedback in a synchronization task: The role of perceptual stability in a visuo-proprioceptive conflict situation.

PubMed

Ceux, Tanja; Montagne, Gilles; Buekers, Martinus J

2010-12-01

The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, 17 participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75%, and 100% of the target cycle duration) in three synchronization modes (in-phase, anti-phase, and intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization mode in contrast to the less stable anti-phase and intermediate mode. Our findings suggest that the complexity of the synchronization mode defines to what extent the visual and/or proprioceptive information source affects the synchronization performance in the present unimanual synchronization task. Copyright © 2010 Elsevier B.V. All rights reserved.

Performance drifts in two-finger cyclical force production tasks performed by one and two actors.

PubMed

Hasanbarani, Fariba; Reschechtko, Sasha; Latash, Mark L

2018-03-01

We explored changes in the cyclical two-finger force performance task caused by turning visual feedback off performed either by the index and middle fingers of the dominant hand or by two index fingers of two persons. Based on an earlier study, we expected drifts in finger force amplitude and midpoint without a drift in relative phase. The subjects performed two rhythmical tasks at 1 Hz while paced by an auditory metronome. One of the tasks required cyclical changes in total force magnitude without changes in the sharing of the force between the two fingers. The other task required cyclical changes in the force sharing without changing total force magnitude. Subjects were provided with visual feedback, which showed total force magnitude and force sharing via cursor motion along the vertical and horizontal axes, respectively. Further, visual feedback was turned off, first on the variable that was not required to change and then on both variables. Turning visual feedback off led to a mean force drift toward lower magnitudes while force amplitude increased. There was a consistent drift in the relative phase in the one-hand task with the index finger leading the middle finger. No consistent relative phase drift was seen in the two-person tasks. The shape of the force cycle changed without visual feedback reflected in the lower similarity to a perfect cosine shape and in the higher time spent at lower force magnitudes. The data confirm findings of earlier studies regarding force amplitude and midpoint changes, but falsify predictions of an earlier proposed model with respect to the relative phase changes. We discuss factors that could contribute to the observed relative phase drift in the one-hand tasks including the leader-follower pattern generalized for two-effector tasks performed by one person.

Marginally perceptible outcome feedback, motor learning and implicit processes.

PubMed

Masters, Rich S W; Maxwell, Jon P; Eves, Frank F

2009-09-01

Participants struck 500 golf balls to a concealed target. Outcome feedback was presented at the subjective or objective threshold of awareness of each participant or at a supraliminal threshold. Participants who received fully perceptible (supraliminal) feedback learned to strike the ball onto the target, as did participants who received feedback that was only marginally perceptible (subjective threshold). Participants who received feedback that was not perceptible (objective threshold) showed no learning. Upon transfer to a condition in which the target was unconcealed, performance increased in both the subjective and the objective threshold condition, but decreased in the supraliminal condition. In all three conditions, participants reported minimal declarative knowledge of their movements, suggesting that deliberate hypothesis testing about how best to move in order to perform the motor task successfully was disrupted by the impoverished disposition of the visual outcome feedback. It was concluded that sub-optimally perceptible visual feedback evokes implicit processes.

Stability of hand force production. I. Hand level control variables and multifinger synergies.

PubMed

Reschechtko, Sasha; Latash, Mark L

2017-12-01

We combined the theory of neural control of movement with referent coordinates and the uncontrolled manifold hypothesis to explore synergies stabilizing the hand action in accurate four-finger pressing tasks. In particular, we tested a hypothesis on two classes of synergies, those among the four fingers and those within a pair of control variables, stabilizing hand action under visual feedback and disappearing without visual feedback. Subjects performed four-finger total force and moment production tasks under visual feedback; the feedback was later partially or completely removed. The "inverse piano" device was used to lift and lower the fingers smoothly at the beginning and at the end of each trial. These data were used to compute pairs of hypothetical control variables. Intertrial analysis of variance within the finger force space was used to quantify multifinger synergies stabilizing both force and moment. A data permutation method was used to quantify synergies among control variables. Under visual feedback, synergies in the spaces of finger forces and hypothetical control variables were found to stabilize total force. Without visual feedback, the subjects showed a force drift to lower magnitudes and a moment drift toward pronation. This was accompanied by disappearance of the four-finger synergies and strong attenuation of the control variable synergies. The indexes of the two types of synergies correlated with each other. The findings are interpreted within the scheme with multiple levels of abundant variables. NEW & NOTEWORTHY We extended the idea of hierarchical control with referent spatial coordinates for the effectors and explored two types of synergies stabilizing multifinger force production tasks. We observed synergies among finger forces and synergies between hypothetical control variables that stabilized performance under visual feedback but failed to stabilize it after visual feedback had been removed. Indexes of two types of synergies correlated with each other. The data suggest the existence of multiple mechanisms stabilizing motor actions. Copyright © 2017 the American Physiological Society.

The effect of haptic guidance and visual feedback on learning a complex tennis task.

PubMed

Marchal-Crespo, Laura; van Raai, Mark; Rauter, Georg; Wolf, Peter; Riener, Robert

2013-11-01

While haptic guidance can improve ongoing performance of a motor task, several studies have found that it ultimately impairs motor learning. However, some recent studies suggest that the haptic demonstration of optimal timing, rather than movement magnitude, enhances learning in subjects trained with haptic guidance. Timing of an action plays a crucial role in the proper accomplishment of many motor skills, such as hitting a moving object (discrete timing task) or learning a velocity profile (time-critical tracking task). The aim of the present study is to evaluate which feedback conditions-visual or haptic guidance-optimize learning of the discrete and continuous elements of a timing task. The experiment consisted in performing a fast tennis forehand stroke in a virtual environment. A tendon-based parallel robot connected to the end of a racket was used to apply haptic guidance during training. In two different experiments, we evaluated which feedback condition was more adequate for learning: (1) a time-dependent discrete task-learning to start a tennis stroke and (2) a tracking task-learning to follow a velocity profile. The effect that the task difficulty and subject's initial skill level have on the selection of the optimal training condition was further evaluated. Results showed that the training condition that maximizes learning of the discrete time-dependent motor task depends on the subjects' initial skill level. Haptic guidance was especially suitable for less-skilled subjects and in especially difficult discrete tasks, while visual feedback seems to benefit more skilled subjects. Additionally, haptic guidance seemed to promote learning in a time-critical tracking task, while visual feedback tended to deteriorate the performance independently of the task difficulty and subjects' initial skill level. Haptic guidance outperformed visual feedback, although additional studies are needed to further analyze the effect of other types of feedback visualization on motor learning of time-critical tasks.

Lingual electrotactile stimulation as an alternative sensory feedback pathway for brain-computer interface applications

NASA Astrophysics Data System (ADS)

Wilson, J. Adam; Walton, Léo M.; Tyler, Mitch; Williams, Justin

2012-08-01

This article describes a new method of providing feedback during a brain-computer interface movement task using a non-invasive, high-resolution electrotactile vision substitution system. We compared the accuracy and movement times during a center-out cursor movement task, and found that the task performance with tactile feedback was comparable to visual feedback for 11 participants. These subjects were able to modulate the chosen BCI EEG features during both feedback modalities, indicating that the type of feedback chosen does not matter provided that the task information is clearly conveyed through the chosen medium. In addition, we tested a blind subject with the tactile feedback system, and found that the training time, accuracy, and movement times were indistinguishable from results obtained from subjects using visual feedback. We believe that BCI systems with alternative feedback pathways should be explored, allowing individuals with severe motor disabilities and accompanying reduced visual and sensory capabilities to effectively use a BCI.

Learning to See: Enhancing Student Learning through Videotaped Feedback

ERIC Educational Resources Information Center

Yakura, Elaine K.

2009-01-01

Feedback is crucial to developing skills, but meaningful feedback is difficult to provide. Classroom videotaping can provide effective feedback on student performance, but for video feedback to be most helpful, students must develop a type of "visual intelligence"--analytical skills that increase critical thinking and self-awareness. The author…

Evaluation of Augmented Reality Feedback in Surgical Training Environment.

PubMed

Zahiri, Mohsen; Nelson, Carl A; Oleynikov, Dmitry; Siu, Ka-Chun

2018-02-01

Providing computer-based laparoscopic surgical training has several advantages that enhance the training process. Self-evaluation and real-time performance feedback are 2 of these advantages, which avoid dependency of trainees on expert feedback. The goal of this study was to investigate the use of a visual time indicator as real-time feedback correlated with the laparoscopic surgical training. Twenty novices participated in this study working with (and without) different presentations of time indicators. They performed a standard peg transfer task, and their completion times and muscle activity were recorded and compared. Also of interest was whether the use of this type of feedback induced any side effect in terms of motivation or muscle fatigue. Of the 20 participants, 15 (75%) preferred using a time indicator in the training process rather than having no feedback. However, time to task completion showed no significant difference in performance with the time indicator; furthermore, no significant differences in muscle activity or muscle fatigue were detected with/without time feedback. The absence of significant difference between task performance with/without time feedback shows that using visual real-time feedback can be included in surgical training based on user preference. Trainees may benefit from this type of feedback in the form of increased motivation. The extent to which this can influence training frequency leading to performance improvement is a question for further study.

Proprioceptive feedback determines visuomotor gain in Drosophila

PubMed Central

Bartussek, Jan; Lehmann, Fritz-Olaf

2016-01-01

Multisensory integration is a prerequisite for effective locomotor control in most animals. Especially, the impressive aerial performance of insects relies on rapid and precise integration of multiple sensory modalities that provide feedback on different time scales. In flies, continuous visual signalling from the compound eyes is fused with phasic proprioceptive feedback to ensure precise neural activation of wing steering muscles (WSM) within narrow temporal phase bands of the stroke cycle. This phase-locked activation relies on mechanoreceptors distributed over wings and gyroscopic halteres. Here we investigate visual steering performance of tethered flying fruit flies with reduced haltere and wing feedback signalling. Using a flight simulator, we evaluated visual object fixation behaviour, optomotor altitude control and saccadic escape reflexes. The behavioural assays show an antagonistic effect of wing and haltere signalling on visuomotor gain during flight. Compared with controls, suppression of haltere feedback attenuates while suppression of wing feedback enhances the animal’s wing steering range. Our results suggest that the generation of motor commands owing to visual perception is dynamically controlled by proprioception. We outline a potential physiological mechanism based on the biomechanical properties of WSM and sensory integration processes at the level of motoneurons. Collectively, the findings contribute to our general understanding how moving animals integrate sensory information with dynamically changing temporal structure. PMID:26909184

Effects of interactive visual feedback training on post-stroke pusher syndrome: a pilot randomized controlled study.

PubMed

Yang, Yea-Ru; Chen, Yi-Hua; Chang, Heng-Chih; Chan, Rai-Chi; Wei, Shun-Hwa; Wang, Ray-Yau

2015-10-01

We investigated the effects of a computer-generated interactive visual feedback training program on the recovery from pusher syndrome in stroke patients. Assessor-blinded, pilot randomized controlled study. A total of 12 stroke patients with pusher syndrome were randomly assigned to either the experimental group (N = 7, computer-generated interactive visual feedback training) or control group (N = 5, mirror visual feedback training). The scale for contraversive pushing for severity of pusher syndrome, the Berg Balance Scale for balance performance, and the Fugl-Meyer assessment scale for motor control were the outcome measures. Patients were assessed pre- and posttraining. A comparison of pre- and posttraining assessment results revealed that both training programs led to the following significant changes: decreased severity of pusher syndrome scores (decreases of 4.0 ± 1.1 and 1.4 ± 1.0 in the experimental and control groups, respectively); improved balance scores (increases of 14.7 ± 4.3 and 7.2 ± 1.6 in the experimental and control groups, respectively); and higher scores for lower extremity motor control (increases of 8.4 ± 2.2 and 5.6 ± 3.3 in the experimental and control groups, respectively). Furthermore, the computer-generated interactive visual feedback training program produced significantly better outcomes in the improvement of pusher syndrome (p < 0.01) and balance (p < 0.05) compared with the mirror visual feedback training program. Although both training programs were beneficial, the computer-generated interactive visual feedback training program more effectively aided recovery from pusher syndrome compared with mirror visual feedback training. © The Author(s) 2014.

Improving training of laparoscopic tissue manipulation skills using various visual force feedback types.

PubMed

Smit, Daan; Spruit, Edward; Dankelman, Jenny; Tuijthof, Gabrielle; Hamming, Jaap; Horeman, Tim

2017-01-01

Visual force feedback allows trainees to learn laparoscopic tissue manipulation skills. The aim of this experimental study was to find the most efficient visual force feedback method to acquire these skills. Retention and transfer validity to an untrained task were assessed. Medical students without prior experience in laparoscopy were randomized in three groups: Constant Force Feedback (CFF) (N = 17), Bandwidth Force Feedback (BFF) (N = 16) and Fade-in Force Feedback (N = 18). All participants performed a pretest, training, post-test and follow-up test. The study involved two dissimilar tissue manipulation tasks, one for training and one to assess transferability. Participants performed six trials of the training task. A force platform was used to record several force parameters. A paired-sample t test showed overall lower force parameter outcomes in the post-test compared to the pretest (p < .001). A week later, the force parameter outcomes were still significantly lower than found in the pretest (p < .005). Participants also performed the transfer task in the post-test (p < .02) and follow-up (p < .05) test with lower force parameter outcomes compared to the pretest. A one-way MANOVA indicated that in the post-test the CFF group applied 50 % less Mean Absolute Nonzero Force (p = .005) than the BFF group. All visual force feedback methods showed to be effective in decreasing tissue manipulation force as no major differences were found between groups in the post and follow-up trials. The BFF method is preferred for it respects individual progress and minimizes distraction.

Delayed visual feedback affects both manual tracking and grip force control when transporting a handheld object.

PubMed

Sarlegna, Fabrice R; Baud-Bovy, Gabriel; Danion, Frédéric

2010-08-01

When we manipulate an object, grip force is adjusted in anticipation of the mechanical consequences of hand motion (i.e., load force) to prevent the object from slipping. This predictive behavior is assumed to rely on an internal representation of the object dynamic properties, which would be elaborated via visual information before the object is grasped and via somatosensory feedback once the object is grasped. Here we examined this view by investigating the effect of delayed visual feedback during dextrous object manipulation. Adult participants manually tracked a sinusoidal target by oscillating a handheld object whose current position was displayed as a cursor on a screen along with the visual target. A delay was introduced between actual object displacement and cursor motion. This delay was linearly increased (from 0 to 300 ms) and decreased within 2-min trials. As previously reported, delayed visual feedback altered performance in manual tracking. Importantly, although the physical properties of the object remained unchanged, delayed visual feedback altered the timing of grip force relative to load force by about 50 ms. Additional experiments showed that this effect was not due to task complexity nor to manual tracking. A model inspired by the behavior of mass-spring systems suggests that delayed visual feedback may have biased the representation of object dynamics. Overall, our findings support the idea that visual feedback of object motion can influence the predictive control of grip force even when the object is grasped.

Effect of biased feedback on motor imagery learning in BCI-teleoperation system.

PubMed

Alimardani, Maryam; Nishio, Shuichi; Ishiguro, Hiroshi

2014-01-01

Feedback design is an important issue in motor imagery BCI systems. Regardless, to date it has not been reported how feedback presentation can optimize co-adaptation between a human brain and such systems. This paper assesses the effect of realistic visual feedback on users' BCI performance and motor imagery skills. We previously developed a tele-operation system for a pair of humanlike robotic hands and showed that BCI control of such hands along with first-person perspective visual feedback of movements can arouse a sense of embodiment in the operators. In the first stage of this study, we found that the intensity of this ownership illusion was associated with feedback presentation and subjects' performance during BCI motion control. In the second stage, we probed the effect of positive and negative feedback bias on subjects' BCI performance and motor imagery skills. Although the subject specific classifier, which was set up at the beginning of experiment, detected no significant change in the subjects' online performance, evaluation of brain activity patterns revealed that subjects' self-regulation of motor imagery features improved due to a positive bias of feedback and a possible occurrence of ownership illusion. Our findings suggest that in general training protocols for BCIs, manipulation of feedback can play an important role in the optimization of subjects' motor imagery skills.

Reproducibility of The Abdominal and Chest Wall Position by Voluntary Breath-Hold Technique Using a Laser-Based Monitoring and Visual Feedback System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, Katsumasa; Shioyama, Yoshiyuki; Nomoto, Satoru

2007-05-01

Purpose: The voluntary breath-hold (BH) technique is a simple method to control the respiration-related motion of a tumor during irradiation. However, the abdominal and chest wall position may not be accurately reproduced using the BH technique. The purpose of this study was to examine whether visual feedback can reduce the fluctuation in wall motion during BH using a new respiratory monitoring device. Methods and Materials: We developed a laser-based BH monitoring and visual feedback system. For this study, five healthy volunteers were enrolled. The volunteers, practicing abdominal breathing, performed shallow end-expiration BH (SEBH), shallow end-inspiration BH (SIBH), and deep end-inspirationmore » BH (DIBH) with or without visual feedback. The abdominal and chest wall positions were measured at 80-ms intervals during BHs. Results: The fluctuation in the chest wall position was smaller than that of the abdominal wall position. The reproducibility of the wall position was improved by visual feedback. With a monitoring device, visual feedback reduced the mean deviation of the abdominal wall from 2.1 {+-} 1.3 mm to 1.5 {+-} 0.5 mm, 2.5 {+-} 1.9 mm to 1.1 {+-} 0.4 mm, and 6.6 {+-} 2.4 mm to 2.6 {+-} 1.4 mm in SEBH, SIBH, and DIBH, respectively. Conclusions: Volunteers can perform the BH maneuver in a highly reproducible fashion when informed about the position of the wall, although in the case of DIBH, the deviation in the wall position remained substantial.« less

Effects of continuous visual feedback during sitting balance training in chronic stroke survivors.

PubMed

Pellegrino, Laura; Giannoni, Psiche; Marinelli, Lucio; Casadio, Maura

2017-10-16

Postural control deficits are common in stroke survivors and often the rehabilitation programs include balance training based on visual feedback to improve the control of body position or of the voluntary shift of body weight in space. In the present work, a group of chronic stroke survivors, while sitting on a force plate, exercised the ability to control their Center of Pressure with a training based on continuous visual feedback. The goal of this study was to test if and to what extent chronic stroke survivors were able to learn the task and transfer the learned ability to a condition without visual feedback and to directions and displacement amplitudes different from those experienced during training. Eleven chronic stroke survivors (5 Male - 6 Female, age: 59.72 ± 12.84 years) participated in this study. Subjects were seated on a stool positioned on top of a custom-built force platform. Their Center of Pressure positions were mapped to the coordinate of a cursor on a computer monitor. During training, the cursor position was always displayed and the subjects were to reach targets by shifting their Center of Pressure by moving their trunk. Pre and post-training subjects were required to reach without visual feedback of the cursor the training targets as well as other targets positioned in different directions and displacement amplitudes. During training, most stroke survivors were able to perform the required task and to improve their performance in terms of duration, smoothness, and movement extent, although not in terms of movement direction. However, when we removed the visual feedback, most of them had no improvement with respect to their pre-training performance. This study suggests that postural training based exclusively on continuous visual feedback can provide limited benefits for stroke survivors, if administered alone. However, the positive gains observed during training justify the integration of this technology-based protocol in a well-structured and personalized physiotherapy training, where the combination of the two approaches may lead to functional recovery.

Effects of Vibrotactile Feedback on Human Learning of Arm Motions

PubMed Central

Bark, Karlin; Hyman, Emily; Tan, Frank; Cha, Elizabeth; Jax, Steven A.; Buxbaum, Laurel J.; Kuchenbecker, Katherine J.

2015-01-01

Tactile cues generated from lightweight, wearable actuators can help users learn new motions by providing immediate feedback on when and how to correct their movements. We present a vibrotactile motion guidance system that measures arm motions and provides vibration feedback when the user deviates from a desired trajectory. A study was conducted to test the effects of vibrotactile guidance on a subject’s ability to learn arm motions. Twenty-six subjects learned motions of varying difficulty with both visual (V), and visual and vibrotactile (VVT) feedback over the course of four days of training. After four days of rest, subjects returned to perform the motions from memory with no feedback. We found that augmenting visual feedback with vibrotactile feedback helped subjects reduce the root mean square (rms) angle error of their limb significantly while they were learning the motions, particularly for 1DOF motions. Analysis of the retention data showed no significant difference in rms angle errors between feedback conditions. PMID:25486644

Fitts’ Law in the Control of Isometric Grip Force With Naturalistic Targets

PubMed Central

Thumser, Zachary C.; Slifkin, Andrew B.; Beckler, Dylan T.; Marasco, Paul D.

2018-01-01

Fitts’ law models the relationship between amplitude, precision, and speed of rapid movements. It is widely used to quantify performance in pointing tasks, study human-computer interaction, and generally to understand perceptual-motor information processes, including research to model performance in isometric force production tasks. Applying Fitts’ law to an isometric grip force task would allow for quantifying grasp performance in rehabilitative medicine and may aid research on prosthetic control and design. We examined whether Fitts’ law would hold when participants attempted to accurately produce their intended force output while grasping a manipulandum when presented with images of various everyday objects (we termed this the implicit task). Although our main interest was the implicit task, to benchmark it and establish validity, we examined performance against a more standard visual feedback condition via a digital force-feedback meter on a video monitor (explicit task). Next, we progressed from visual force feedback with force meter targets to the same targets without visual force feedback (operating largely on feedforward control with tactile feedback). This provided an opportunity to see if Fitts’ law would hold without vision, and allowed us to progress toward the more naturalistic implicit task (which does not include visual feedback). Finally, we changed the nature of the targets from requiring explicit force values presented as arrows on a force-feedback meter (explicit targets) to the more naturalistic and intuitive target forces implied by images of objects (implicit targets). With visual force feedback the relation between task difficulty and the time to produce the target grip force was predicted by Fitts’ law (average r2 = 0.82). Without vision, average grip force scaled accurately although force variability was insensitive to the target presented. In contrast, images of everyday objects generated more reliable grip forces without the visualized force meter. In sum, population means were well-described by Fitts’ law for explicit targets with vision (r2 = 0.96) and implicit targets (r2 = 0.89), but not as well-described for explicit targets without vision (r2 = 0.54). Implicit targets should provide a realistic see-object-squeeze-object test using Fitts’ law to quantify the relative speed-accuracy relationship of any given grasper. PMID:29773999

Real-time evaluation and visualization of learner performance in a mixed-reality environment for clinical breast examination.

PubMed

Kotranza, Aaron; Lind, D Scott; Lok, Benjamin

2012-07-01

We investigate the efficacy of incorporating real-time feedback of user performance within mixed-reality environments (MREs) for training real-world tasks with tightly coupled cognitive and psychomotor components. This paper presents an approach to providing real-time evaluation and visual feedback of learner performance in an MRE for training clinical breast examination (CBE). In a user study of experienced and novice CBE practitioners (n = 69), novices receiving real-time feedback performed equivalently or better than more experienced practitioners in the completeness and correctness of the exam. A second user study (n = 8) followed novices through repeated practice of CBE in the MRE. Results indicate that skills improvement in the MRE transfers to the real-world task of CBE of human patients. This initial case study demonstrates the efficacy of MREs incorporating real-time feedback for training real-world cognitive-psychomotor tasks.

Can You Hear That Peak? Utilization of Auditory and Visual Feedback at Peak Limb Velocity.

PubMed

Loria, Tristan; de Grosbois, John; Tremblay, Luc

2016-09-01

At rest, the central nervous system combines and integrates multisensory cues to yield an optimal percept. When engaging in action, the relative weighing of sensory modalities has been shown to be altered. Because the timing of peak velocity is the critical moment in some goal-directed movements (e.g., overarm throwing), the current study sought to test whether visual and auditory cues are optimally integrated at that specific kinematic marker when it is the critical part of the trajectory. Participants performed an upper-limb movement in which they were required to reach their peak limb velocity when the right index finger intersected a virtual target (i.e., a flinging movement). Brief auditory, visual, or audiovisual feedback (i.e., 20 ms in duration) was provided to participants at peak limb velocity. Performance was assessed primarily through the resultant position of peak limb velocity and the variability of that position. Relative to when no feedback was provided, auditory feedback significantly reduced the resultant endpoint variability of the finger position at peak limb velocity. However, no such reductions were found for the visual or audiovisual feedback conditions. Further, providing both auditory and visual cues concurrently also failed to yield the theoretically predicted improvements in endpoint variability. Overall, the central nervous system can make significant use of an auditory cue but may not optimally integrate a visual and auditory cue at peak limb velocity, when peak velocity is the critical part of the trajectory.

Psycho-physiological assessment of a prosthetic hand sensory feedback system based on an auditory display: a preliminary study.

PubMed

Gonzalez, Jose; Soma, Hirokazu; Sekine, Masashi; Yu, Wenwei

2012-06-09

Prosthetic hand users have to rely extensively on visual feedback, which seems to lead to a high conscious burden for the users, in order to manipulate their prosthetic devices. Indirect methods (electro-cutaneous, vibrotactile, auditory cues) have been used to convey information from the artificial limb to the amputee, but the usability and advantages of these feedback methods were explored mainly by looking at the performance results, not taking into account measurements of the user's mental effort, attention, and emotions. The main objective of this study was to explore the feasibility of using psycho-physiological measurements to assess cognitive effort when manipulating a robot hand with and without the usage of a sensory substitution system based on auditory feedback, and how these psycho-physiological recordings relate to temporal and grasping performance in a static setting. 10 male subjects (26+/-years old), participated in this study and were asked to come for 2 consecutive days. On the first day the experiment objective, tasks, and experiment setting was explained. Then, they completed a 30 minutes guided training. On the second day each subject was tested in 3 different modalities: Auditory Feedback only control (AF), Visual Feedback only control (VF), and Audiovisual Feedback control (AVF). For each modality they were asked to perform 10 trials. At the end of each test, the subject had to answer the NASA TLX questionnaire. Also, during the test the subject's EEG, ECG, electro-dermal activity (EDA), and respiration rate were measured. The results show that a higher mental effort is needed when the subjects rely only on their vision, and that this effort seems to be reduced when auditory feedback is added to the human-machine interaction (multimodal feedback). Furthermore, better temporal performance and better grasping performance was obtained in the audiovisual modality. The performance improvements when using auditory cues, along with vision (multimodal feedback), can be attributed to a reduced attentional demand during the task, which can be attributed to a visual "pop-out" or enhance effect. Also, the NASA TLX, the EEG's Alpha and Beta band, and the Heart Rate could be used to further evaluate sensory feedback systems in prosthetic applications.

Delayed action does not always require the ventral stream: a study on a patient with visual form agnosia.

PubMed

Hesse, Constanze; Schenk, Thomas

2014-05-01

It has been suggested that while movements directed at visible targets are processed within the dorsal stream, movements executed after delay rely on the visual representations of the ventral stream (Milner & Goodale, 2006). This interpretation is supported by the observation that a patient with ventral stream damage (D.F.) has trouble performing accurate movements after a delay, but performs normally when the target is visible during movement programming. We tested D.F.'s visuomotor performance in a letter-posting task whilst varying the amount of visual feedback available. Additionally, we also varied whether D.F. received tactile feedback at the end of each trial (posting through a letter box vs posting on a screen) and whether environmental cues were available during the delay period (removing the target only vs suppressing vision completely with shutter glasses). We found that in the absence of environmental cues patient D.F. was unaffected by the introduction of delay and performed as accurately as healthy controls. However, when environmental cues and vision of the moving hand were available during and after the delay period, D.F.'s visuomotor performance was impaired. Thus, while healthy controls benefit from the availability of environmental landmarks and/or visual feedback of the moving hand, such cues seem less beneficial to D.F. Taken together our findings suggest that ventral stream damage does not always impact the ability to make delayed movements but compromises the ability to use environmental landmarks and visual feedback efficiently. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis.

PubMed

Schiefer, Matthew; Tan, Daniel; Sidek, Steven M; Tyler, Dustin J

2016-02-01

Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject's sense of embodiment with a survey and his self-confidence. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

Altered visual strategies and attention are related to increased force fluctuations during a pinch grip task in older adults.

PubMed

Keenan, Kevin G; Huddleston, Wendy E; Ernest, Bradley E

2017-11-01

The purpose of the study was to determine the visual strategies used by older adults during a pinch grip task and to assess the relations between visual strategy, deficits in attention, and increased force fluctuations in older adults. Eye movements of 23 older adults (>65 yr) were monitored during a low-force pinch grip task while subjects viewed three common visual feedback displays. Performance on the Grooved Pegboard test and an attention task (which required no concurrent hand movements) was also measured. Visual strategies varied across subjects and depended on the type of visual feedback provided to the subjects. First, while viewing a high-gain compensatory feedback display (horizontal bar moving up and down with force), 9 of 23 older subjects adopted a strategy of performing saccades during the task, which resulted in 2.5 times greater force fluctuations in those that exhibited saccades compared with those who maintained fixation near the target line. Second, during pursuit feedback displays (force trace moving left to right across screen and up and down with force), all subjects exhibited multiple saccades, and increased force fluctuations were associated ( r s = 0.6; P = 0.002) with fewer saccades during the pursuit task. Also, decreased low-frequency (<4 Hz) force fluctuations and Grooved Pegboard times were significantly related ( P = 0.033 and P = 0.005, respectively) with higher (i.e., better) attention z scores. Comparison of these results with our previously published results in young subjects indicates that saccadic eye movements and attention are related to force control in older adults. NEW & NOTEWORTHY The significant contributions of the study are the addition of eye movement data and an attention task to explain differences in hand motor control across different visual displays in older adults. Older participants used different visual strategies across varying feedback displays, and saccadic eye movements were related with motor performance. In addition, those older individuals with deficits in attention had impaired motor performance on two different hand motor control tasks, including the Grooved Pegboard test. Copyright © 2017 the American Physiological Society.

Improvements in force variability and structure from vision- to memory-guided submaximal isometric knee extension in subacute stroke.

PubMed

Chow, John W; Stokic, Dobrivoje S

2018-03-01

We examined changes in variability, accuracy, frequency composition, and temporal regularity of force signal from vision-guided to memory-guided force-matching tasks in 17 subacute stroke and 17 age-matched healthy subjects. Subjects performed a unilateral isometric knee extension at 10, 30, and 50% of peak torque [maximum voluntary contraction (MVC)] for 10 s (3 trials each). Visual feedback was removed at the 5-s mark in the first two trials (feedback withdrawal), and 30 s after the second trial the subjects were asked to produce the target force without visual feedback (force recall). The coefficient of variation and constant error were used to quantify force variability and accuracy. Force structure was assessed by the median frequency, relative spectral power in the 0-3-Hz band, and sample entropy of the force signal. At 10% MVC, the force signal in subacute stroke subjects became steadier, more broadband, and temporally more irregular after the withdrawal of visual feedback, with progressively larger error at higher contraction levels. Also, the lack of modulation in the spectral frequency at higher force levels with visual feedback persisted in both the withdrawal and recall conditions. In terms of changes from the visual feedback condition, the feedback withdrawal produced a greater difference between the paretic, nonparetic, and control legs than the force recall. The overall results suggest improvements in force variability and structure from vision- to memory-guided force control in subacute stroke despite decreased accuracy. Different sensory-motor memory retrieval mechanisms seem to be involved in the feedback withdrawal and force recall conditions, which deserves further study. NEW & NOTEWORTHY We demonstrate that in the subacute phase of stroke, force signals during a low-level isometric knee extension become steadier, more broadband in spectral power, and more complex after removal of visual feedback. Larger force errors are produced when recalling target forces than immediately after withdrawing visual feedback. Although visual feedback offers better accuracy, it worsens force variability and structure in subacute stroke. The feedback withdrawal and force recall conditions seem to involve different memory retrieval mechanisms.

Unintentional force changes in cyclical tasks performed by an abundant system: Empirical observations and a dynamical model.

PubMed

Reschechtko, Sasha; Hasanbarani, Fariba; Akulin, Vladimir M; Latash, Mark L

2017-05-14

The study explored unintentional force changes elicited by removing visual feedback during cyclical, two-finger isometric force production tasks. Subjects performed two types of tasks at 1Hz, paced by an auditory metronome. One - Force task - required cyclical changes in total force while maintaining the sharing, defined as relative contribution of a finger to total force. The other task - Share task - required cyclical changes in sharing while keeping total force unchanged. Each trial started under full visual feedback on both force and sharing; subsequently, feedback on the variable that was instructed to stay constant was frozen, and finally feedback on the other variable was also removed. In both tasks, turning off visual feedback on total force elicited a drop in the mid-point of the force cycle and an increase in the peak-to-peak force amplitude. Turning off visual feedback on sharing led to a drift of mean share toward 50:50 across both tasks. Without visual feedback there was consistent deviation of the two force time series from the in-phase pattern (typical of the Force task) and from the out-of-phase pattern (typical of the Share task). This finding is in contrast to most earlier studies that demonstrated only two stable patterns, in-phase and out-of-phase. We interpret the results as consequences of drifts of parameters in a dynamical system leading in particular to drifts in the referent finger coordinates toward their actual coordinates. The relative phase desynchronization is caused by the right-left differences in the hypothesized drift processes, consistent with the dynamic dominance hypothesis. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Unintentional force changes in cyclical tasks performed by an abundant system: Empirical observations and a dynamical model

PubMed Central

Reschechtko, Sasha; Hasanbarani, Fariba; Akulin, Vladimir M.; Latash, Mark L.

2017-01-01

The study explored unintentional force changes elicited by removing visual feedback during cyclical, two-finger isometric force production tasks. Subjects performed two types of tasks at 1 Hz, paced by an auditory metronome. One – Force task – required cyclical changes in total force while maintaining the sharing, defined as relative contribution of a finger to total force. The other task – Share task – required cyclical changes in sharing while keeping total force unchanged. Each trial started under full visual feedback on both force and sharing; subsequently, feedback on the variable that was instructed to stay constant was frozen, and finally feedback on the other variable was also removed. In both tasks, turning off visual feedback on total force elicited a drop in the mid-point of the force cycle and an increase in the peak-to-peak force amplitude. Turning off visual feedback on sharing led to a drift of mean share toward 50:50 across both tasks. Without visual feedback there was consistent deviation of the two force time series from the in-phase pattern (typical of the Force task) and from the out-of-phase pattern (typical of the Share task). This finding is in contrast to most earlier studies that demonstrated only two stable patterns, in-phase and out-of-phase. We interpret the results as consequences of drifts of parameters in a dynamical system leading in particular to drifts in the referent finger coordinates toward their actual coordinates. The relative phase desynchronization is caused by the right-left differences in the hypothesized drift processes, consistent with the dynamic dominance hypothesis. PMID:28344070

Neural Substrates of Visual Spatial Coding and Visual Feedback Control for Hand Movements in Allocentric and Target-Directed Tasks

PubMed Central

Thaler, Lore; Goodale, Melvyn A.

2011-01-01

Neuropsychological evidence suggests that different brain areas may be involved in movements that are directed at visual targets (e.g., pointing or reaching), and movements that are based on allocentric visual information (e.g., drawing or copying). Here we used fMRI to investigate the neural correlates of these two types of movements in healthy volunteers. Subjects (n = 14) performed right hand movements in either a target-directed task (moving a cursor to a target dot) or an allocentric task (moving a cursor to reproduce the distance and direction between two distal target dots) with or without visual feedback about their hand movement. Movements were monitored with an MR compatible touch panel. A whole brain analysis revealed that movements in allocentric conditions led to an increase in activity in the fundus of the left intra-parietal sulcus (IPS), in posterior IPS, in bilateral dorsal premotor cortex (PMd), and in the lateral occipital complex (LOC). Visual feedback in both target-directed and allocentric conditions led to an increase in activity in area MT+, superior parietal–occipital cortex (SPOC), and posterior IPS (all bilateral). In addition, we found that visual feedback affected brain activity differently in target-directed as compared to allocentric conditions, particularly in the pre-supplementary motor area, PMd, IPS, and parieto-occipital cortex. Our results, in combination with previous findings, suggest that the LOC is essential for allocentric visual coding and that SPOC is involved in visual feedback control. The differences in brain activity between target-directed and allocentric visual feedback conditions may be related to behavioral differences in visual feedback control. Our results advance the understanding of the visual coordinate frame used by the LOC. In addition, because of the nature of the allocentric task, our results have relevance for the understanding of neural substrates of magnitude estimation and vector coding of movements. PMID:21941474

Objective Assessment of Laparoscopic Force and Psychomotor Skills in a Novel Virtual Reality-Based Haptic Simulator.

PubMed

Prasad, M S Raghu; Manivannan, Muniyandi; Manoharan, Govindan; Chandramohan, S M

2016-01-01

Most of the commercially available virtual reality-based laparoscopic simulators do not effectively evaluate combined psychomotor and force-based laparoscopic skills. Consequently, the lack of training on these critical skills leads to intraoperative errors. To assess the effectiveness of the novel virtual reality-based simulator, this study analyzed the combined psychomotor (i.e., motion or movement) and force skills of residents and expert surgeons. The study also examined the effectiveness of real-time visual force feedback and tool motion during training. Bimanual fundamental (i.e., probing, pulling, sweeping, grasping, and twisting) and complex tasks (i.e., tissue dissection) were evaluated. In both tasks, visual feedback on applied force and tool motion were provided. The skills of the participants while performing the early tasks were assessed with and without visual feedback. Participants performed 5 repetitions of fundamental and complex tasks. Reaction force and instrument acceleration were used as metrics. Surgical Gastroenterology, Government Stanley Medical College and Hospital; Institute of Surgical Gastroenterology, Madras Medical College and Rajiv Gandhi Government General Hospital. Residents (N = 25; postgraduates and surgeons with <2 years of laparoscopic surgery) and expert surgeons (N = 25; surgeons with >4 and ≤10 years of laparoscopic surgery). Residents applied large forces compared with expert surgeons and performed abrupt tool movements (p < 0.001). However, visual + haptic feedback improved the performance of residents (p < 0.001). In complex tasks, visual + haptic feedback did not influence the applied force of expert surgeons, but influenced their tool motion (p < 0.001). Furthermore, in complex tissue sweeping task, expert surgeons applied more force, but were within the tissue damage limits. In both groups, exertion of large forces and abrupt tool motion were observed during grasping, probing or pulling, and tissue sweeping maneuvers (p < 0.001). Modern day curriculum-based training should evaluate the skills of residents with robust force and psychomotor-based exercises for proficient laparoscopy. Visual feedback on force and motion during training has the potential to enhance the learning curve of residents. Copyright © 2016 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

The Effects of Task Clarification, Visual Prompts, and Graphic Feedback on Customer Greeting and Up-Selling in a Restaurant

ERIC Educational Resources Information Center

Squires, James; Wilder, David A.; Fixsen, Amanda; Hess, Erica; Rost, Kristen; Curran, Ryan; Zonneveld, Kimberly

2007-01-01

An intervention consisting of task clarification, visual prompts, and graphic feedback was evaluated to increase customer greeting and up-selling in a restaurant. A combination multiple baseline and reversal design was used to evaluate intervention effects. Although all interventions improved performance over baseline, the delivery of graphic…

Perceptual learning increases the strength of the earliest signals in visual cortex.

PubMed

Bao, Min; Yang, Lin; Rios, Cristina; He, Bin; Engel, Stephen A

2010-11-10

Training improves performance on most visual tasks. Such perceptual learning can modify how information is read out from, and represented in, later visual areas, but effects on early visual cortex are controversial. In particular, it remains unknown whether learning can reshape neural response properties in early visual areas independent from feedback arising in later cortical areas. Here, we tested whether learning can modify feedforward signals in early visual cortex as measured by the human electroencephalogram. Fourteen subjects were trained for >24 d to detect a diagonal grating pattern in one quadrant of the visual field. Training improved performance, reducing the contrast needed for reliable detection, and also reliably increased the amplitude of the earliest component of the visual evoked potential, the C1. Control orientations and locations showed smaller effects of training. Because the C1 arises rapidly and has a source in early visual cortex, our results suggest that learning can increase early visual area response through local receptive field changes without feedback from later areas.

Seeing the Errors You Feel Enhances Locomotor Performance but Not Learning.

PubMed

Roemmich, Ryan T; Long, Andrew W; Bastian, Amy J

2016-10-24

In human motor learning, it is thought that the more information we have about our errors, the faster we learn. Here, we show that additional error information can lead to improved motor performance without any concomitant improvement in learning. We studied split-belt treadmill walking that drives people to learn a new gait pattern using sensory prediction errors detected by proprioceptive feedback. When we also provided visual error feedback, participants acquired the new walking pattern far more rapidly and showed accelerated restoration of the normal walking pattern during washout. However, when the visual error feedback was removed during either learning or washout, errors reappeared with performance immediately returning to the level expected based on proprioceptive learning alone. These findings support a model with two mechanisms: a dual-rate adaptation process that learns invariantly from sensory prediction error detected by proprioception and a visual-feedback-dependent process that monitors learning and corrects residual errors but shows no learning itself. We show that our voluntary correction model accurately predicted behavior in multiple situations where visual feedback was used to change acquisition of new walking patterns while the underlying learning was unaffected. The computational and behavioral framework proposed here suggests that parallel learning and error correction systems allow us to rapidly satisfy task demands without necessarily committing to learning, as the relative permanence of learning may be inappropriate or inefficient when facing environments that are liable to change. Copyright © 2016 Elsevier Ltd. All rights reserved.

Age-Specific Effects of Mirror-Muscle Activity on Cross-Limb Adaptations Under Mirror and Non-Mirror Visual Feedback Conditions.

PubMed

Reissig, Paola; Stöckel, Tino; Garry, Michael I; Summers, Jeffery J; Hinder, Mark R

2015-01-01

Cross-limb transfer (CLT) describes the observation of bilateral performance gains due to unilateral motor practice. Previous research has suggested that CLT may be reduced, or absent, in older adults, possibly due to age-related structural and functional brain changes. Based on research showing increases in CLT due to the provision of mirror visual feedback (MVF) during task execution in young adults, our study aimed to investigate whether MVF can facilitate CLT in older adults, who are known to be more reliant on visual feedback for accurate motor performance. Participants (N = 53) engaged in a short-term training regime (300 movements) involving a ballistic finger task using their dominant hand, while being provided with either visual feedback of their active limb, or a mirror reflection of their active limb (superimposed over the quiescent limb). Performance in both limbs was examined before, during and following the unilateral training. Furthermore, we measured corticospinal excitability (using TMS) at these time points, and assessed muscle activity bilaterally during the task via EMG; these parameters were used to investigate the mechanisms mediating and predicting CLT. Training resulted in significant bilateral performance gains that did not differ as a result of age or visual feedback (both p > 0.1). Training also elicited bilateral increases in corticospinal excitability (p < 0.05). For younger adults, CLT was significantly predicted by performance gains in the trained hand (β = 0.47), whereas for older adults it was significantly predicted by mirror activity in the untrained hand during training (β = 0.60). The present study suggests that older adults are capable of exhibiting CLT to a similar degree to younger adults. The prominent role of mirror activity in the untrained hand for CLT in older adults indicates that bilateral cortical activity during unilateral motor tasks is a compensatory mechanism. In this particular task, MVF did not facilitate the extent of CLT.

Effect of Concurrent Visual Feedback Frequency on Postural Control Learning in Adolescents.

PubMed

Marco-Ahulló, Adrià; Sánchez-Tormo, Alexis; García-Pérez, José A; Villarrasa-Sapiña, Israel; González, Luis M; García-Massó, Xavier

2018-04-13

The purpose was to find better augmented visual feedback frequency (100% or 67%) for learning a balance task in adolescents. Thirty subjects were divided randomly into a control group, and 100% and 67% feedback groups. The three groups performed pretest (3 trials), practice (12 trials), posttest (3 trials) and retention (3 trials, 24 hours later). The reduced feedback group showed lower RMS in the posttest than in the pretest (p = 0.04). The control and reduced feedback groups showed significant lower median frequency in the posttest than in the pretest (p < 0.05). Both feedback groups showed lower values in retention than in the pretest (p < 0.05). Even when the effect of feedback frequency could not be detected in motor learning, 67% of the feedback was recommended for motor adaptation.

Programming of left hand exploits task set but that of right hand depends on recent history.

PubMed

Tang, Rixin; Zhu, Hong

2017-07-01

There are many differences between the left hand and the right hand. But it is not clear if there is a difference in programming between left hand and right hand when the hands perform the same movement. In current study, we carried out two experiments to investigate whether the programming of two hands was equivalent or they exploited different strategies. In the first experiment, participants were required to use one hand to grasp an object with visual feedback or to point to the center of one object without visual feedback on alternate trials, or to grasp an object without visual feedback and to point the center of one object with visual feedback on alternating trials. They then performed the tasks with the other hand. The result was that previous pointing task affected current grasping when it was performed by the left hand, but not the right hand. In experiment 2, we studied if the programming of the left (or right) hand would be affected by the pointing task performed on the previous trial not only by the same hand, but also by the right (or left) hand. Participants pointed and grasped the objects alternately with two hands. The result was similar with Experiment 1, i.e., left-hand grasping was affected by right-hand pointing, whereas right-hand grasping was immune from the interference from left hand. Taken together, the results suggest that when open- and closed-loop trials are interleaved, motor programming of grasping with the right hand was affected by the nature of the online feedback on the previous trial only if it was a grasping trial, suggesting that the trial-to-trial transfer depends on sensorimotor memory and not on task set. In contrast, motor programming of grasping with the left hand can use information about the nature of the online feedback on the previous trial to specify the parameters of the movement, even when the type of movement that occurred was quite different (i.e., pointing) and was performed with the right hand. This suggests that trial-to-trial transfer with the left hand depends on some sort of carry-over of task set for dealing with the availability of visual feedback.

Effects of Visual Feedback and Memory on Unintentional Drifts in Performance During Finger Pressing Tasks

PubMed Central

Solnik, Stanislaw; Qiao, Mu; Latash, Mark L.

2017-01-01

This study tested two hypotheses on the nature of unintentional force drifts elicited by removing visual feedback during accurate force production tasks. The role of working memory (memory hypothesis) was explored in tasks with continuous force production, intermittent force production, and rest intervals over the same time interval. The assumption of unintentional drifts in referent coordinate for the fingertips was tested using manipulations of visual feedback: Young healthy subjects performed accurate steady-state force production tasks by pressing with the two index fingers on individual force sensors with visual feedback on the total force, sharing ratio, both, or none. Predictions based on the memory hypothesis have been falsified. In particular, we observed consistent force drifts to lower force values during continuous force production trials only. No force drift or drifts to higher forces were observed during intermittent force production trials and following rest intervals. The hypotheses based on the idea of drifts in referent finger coordinates have been confirmed. In particular, we observed superposition of two drift processes: A drift of total force to lower magnitudes and a drift of the sharing ratio to 50:50. When visual feedback on total force only was provided, the two finger forces showed drifts in opposite directions. We interpret the findings as evidence for the control of motor actions with changes in referent coordinates for participating effectors. Unintentional drifts in performance are viewed as natural relaxation processes in the involved systems; their typical time reflects stability in the direction of the drift. The magnitude of the drift was higher in the right (dominant) hand, which is consistent with the dynamic dominance hypothesis. PMID:28168396

Curriculum-Based Measurement Performance Indicators: A Tool for Undergraduate Calculus Students to Inform and Direct Their Learning Behavior

ERIC Educational Resources Information Center

Sturges, Linda W.

2010-01-01

The present study investigated the extent to which providing students with individualized performance feedback informed and directed their learning behavior. Individualized performance feedback was delivered to students using curriculum-based measurement progress indicators, either as a visual representation of ongoing performance in the form of a…

Probing feedforward and feedback contributions to awareness with visual masking and transcranial magnetic stimulation.

PubMed

Tapia, Evelina; Beck, Diane M

2014-01-01

A number of influential theories posit that visual awareness relies not only on the initial, stimulus-driven (i.e., feedforward) sweep of activation but also on recurrent feedback activity within and between brain regions. These theories of awareness draw heavily on data from masking paradigms in which visibility of one stimulus is reduced due to the presence of another stimulus. More recently transcranial magnetic stimulation (TMS) has been used to study the temporal dynamics of visual awareness. TMS over occipital cortex affects performance on visual tasks at distinct time points and in a manner that is comparable to visual masking. We draw parallels between these two methods and examine evidence for the neural mechanisms by which visual masking and TMS suppress stimulus visibility. Specifically, both methods have been proposed to affect feedforward as well as feedback signals when applied at distinct time windows relative to stimulus onset and as a result modify visual awareness. Most recent empirical evidence, moreover, suggests that while visual masking and TMS impact stimulus visibility comparably, the processes these methods affect may not be as similar as previously thought. In addition to reviewing both masking and TMS studies that examine feedforward and feedback processes in vision, we raise questions to guide future studies and further probe the necessary conditions for visual awareness.

Unipedal balance in healthy adults: effect of visual environments yielding decreased lateral velocity feedback.

PubMed

Deyer, T W; Ashton-Miller, J A

1999-09-01

To test the (null) hypotheses that the reliability of unipedal balance is unaffected by the attenuation of visual velocity feedback and that, relative to baseline performance, deterioration of balance success rates from attenuated visual velocity feedback will not differ between groups of young men and older women, and the presence (or absence) of a vertical foreground object will not affect balance success rates. Single blind, single case study. University research laboratory. Two volunteer samples: 26 healthy young men (mean age, 20.0yrs; SD, 1.6); 23 healthy older women (mean age, 64.9 yrs; SD, 7.8). Normalized success rates in unipedal balance task. Subjects were asked to transfer to and maintain unipedal stance for 5 seconds in a task near the limit of their balance capabilities. Subjects completed 64 trials: 54 trials of three experimental visual scenes in blocked randomized sequences of 18 trials and 10 trials in a normal visual environment. The experimental scenes included two that provided strong velocity/weak position feedback, one of which had a vertical foreground object (SVWP+) and one without (SVWP-), and one scene providing weak velocity/strong position (WVSP) feedback. Subjects' success rates in the experimental environments were normalized by the success rate in the normal environment in order to allow comparisons between subjects using a mixed model repeated measures analysis of variance. The normalized success rate was significantly greater in SVWP+ than in WVSP (p = .0001) and SVWP- (p = .013). Visual feedback significantly affected the normalized unipedal balance success rates (p = .001); neither the group effect nor the group X visual environment interaction was significant (p = .9362 and p = .5634, respectively). Normalized success rates did not differ significantly between the young men and older women in any visual environment. Near the limit of the young men's or older women's balance capability, the reliability of transfer to unipedal balance was adversely affected by visual environments offering attenuated visual velocity feedback cues and those devoid of vertical foreground objects.

Time to CUSUM: simplified reporting of outcomes in colorectal surgery.

PubMed

Bowles, Thomas A; Watters, David A

2007-07-01

Surgical audit has added value when outcomes can be compared and individual surgeons receive feedback. It is expected that surgeons compare their results with others in similar local practice, the published work, or peers from a craft group audit. Although feedback and comparison are worthy aims, for many surgeons the standards have not been agreed nor is there a craft group audit. The aim of this paper was to develop a reporting format for surgeons carrying out colorectal surgery in a regional hospital. The performance of 13 individual surgeons was analysed using a comprehensive colorectal audit with more than 600 cases. Feedback included caseload and type. Risk stratification of outcomes included; operation urgency, age and Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity. Outcome measures were anastomotic leaks, end stoma rates, unplanned reoperations and mortality. Visual feedback included cumulative summation graphs for elective leaks, mortality and unplanned reoperations. A single A4 page of an individuals performance could be prepared that allowed comparison to the groups data overall. Alerts were set at 2-5% elective leaks, 4-7.5% mortality and 4-11% unplanned return to theatre. Cumulative summation graphs added to this allowed a visual guide to the key performance indicators. Surgeons need to determine how they will review their individual and collective results. These are equally important to the reported work. Detailed analysis of risk-stratified data should occur. Binary outcomes such as leak, mortality and unplanned reoperations may be followed by cumulative summation graphs. This provides a continually updated method of feedback, enabling immediate visual feedback of a surgeon's performance.

Twelve tips to promote successful development of a learner performance dashboard within a medical education program.

PubMed

Boscardin, Christy; Fergus, Kirkpatrick B; Hellevig, Bonnie; Hauer, Karen E

2017-11-09

Easily accessible and interpretable performance data constitute critical feedback for learners that facilitate informed self-assessment and learning planning. To provide this feedback, there has been a proliferation of educational dashboards in recent years. An educational (learner) dashboard systematically delivers timely and continuous feedback on performance and can provide easily visualized and interpreted performance data. In this paper, we provide practical tips for developing a functional, user-friendly individual learner performance dashboard and literature review of dashboard development, assessment theory, and users' perspectives. Considering key design principles and maximizing current technological advances in data visualization techniques can increase dashboard utility and enhance the user experience. By bridging current technology with assessment strategies that support learning, educators can continue to improve the field of learning analytics and design of information management tools such as dashboards in support of improved learning outcomes.

Psycho-physiological assessment of a prosthetic hand sensory feedback system based on an auditory display: a preliminary study

PubMed Central

2012-01-01

Background Prosthetic hand users have to rely extensively on visual feedback, which seems to lead to a high conscious burden for the users, in order to manipulate their prosthetic devices. Indirect methods (electro-cutaneous, vibrotactile, auditory cues) have been used to convey information from the artificial limb to the amputee, but the usability and advantages of these feedback methods were explored mainly by looking at the performance results, not taking into account measurements of the user’s mental effort, attention, and emotions. The main objective of this study was to explore the feasibility of using psycho-physiological measurements to assess cognitive effort when manipulating a robot hand with and without the usage of a sensory substitution system based on auditory feedback, and how these psycho-physiological recordings relate to temporal and grasping performance in a static setting. Methods 10 male subjects (26+/-years old), participated in this study and were asked to come for 2 consecutive days. On the first day the experiment objective, tasks, and experiment setting was explained. Then, they completed a 30 minutes guided training. On the second day each subject was tested in 3 different modalities: Auditory Feedback only control (AF), Visual Feedback only control (VF), and Audiovisual Feedback control (AVF). For each modality they were asked to perform 10 trials. At the end of each test, the subject had to answer the NASA TLX questionnaire. Also, during the test the subject’s EEG, ECG, electro-dermal activity (EDA), and respiration rate were measured. Results The results show that a higher mental effort is needed when the subjects rely only on their vision, and that this effort seems to be reduced when auditory feedback is added to the human-machine interaction (multimodal feedback). Furthermore, better temporal performance and better grasping performance was obtained in the audiovisual modality. Conclusions The performance improvements when using auditory cues, along with vision (multimodal feedback), can be attributed to a reduced attentional demand during the task, which can be attributed to a visual “pop-out” or enhance effect. Also, the NASA TLX, the EEG’s Alpha and Beta band, and the Heart Rate could be used to further evaluate sensory feedback systems in prosthetic applications. PMID:22682425

Impact of online visual feedback on motor acquisition and retention when learning to reach in a force field.

PubMed

Batcho, C S; Gagné, M; Bouyer, L J; Roy, J S; Mercier, C

2016-11-19

When subjects learn a novel motor task, several sources of feedback (proprioceptive, visual or auditory) contribute to the performance. Over the past few years, several studies have investigated the role of visual feedback in motor learning, yet evidence remains conflicting. The aim of this study was therefore to investigate the role of online visual feedback (VFb) on the acquisition and retention stages of motor learning associated with training in a reaching task. Thirty healthy subjects made ballistic reaching movements with their dominant arm toward two targets, on 2 consecutive days using a robotized exoskeleton (KINARM). They were randomly assigned to a group with (VFb) or without (NoVFb) VFb of index position during movement. On day 1, the task was performed before (baseline) and during the application of a velocity-dependent resistive force field (adaptation). To assess retention, participants repeated the task with the force field on day 2. Motor learning was characterized by: (1) the final endpoint error (movement accuracy) and (2) the initial angle (iANG) of deviation (motor planning). Even though both groups showed motor adaptation, the NoVFb-group exhibited slower learning and higher final endpoint error than the VFb-group. In some condition, subjects trained without visual feedback used more curved initial trajectories to anticipate for the perturbation. This observation suggests that learning to reach targets in a velocity-dependent resistive force field is possible even when feedback is limited. However, the absence of VFb leads to different strategies that were only apparent when reaching toward the most challenging target. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The effects of aging on the asymmetry of inter-limb transfer in a visuomotor task.

PubMed

Pan, Zhujun; Van Gemmert, Arend W A

2013-09-01

The direction of the asymmetry of inter-limb transfer has been suggested to identify the specialization of each hemisphere when performing a motor task. In an earlier study, we showed that trajectory information is only transferred from the right to the left hand, while final movement outcome-associated parameters transferred in both directions when right-hand-dominant individuals perform a motor task with visual distorted feedback. In the current study, we try to replicate this finding in young adults and test whether the asymmetry of inter-limb transfer in visuomotor task reduces in older adults, suggesting that hemispheric lateralization reduces with age. Young and older adults (all right-hand-dominant) performed a multidirectional point-to-point drawing task in which the visual feedback was rotated and the gain was increased. Half of the participants in each age group trained with the right hand and the other half trained with the left hand. Performances of both hands with non-distorted and distorted visual feedback were collected from all participants before and after the training session. The results showed that the pattern of inter-limb transfer was similar between young and older adults, i.e., inter-limb transfer is asymmetric for initial direction and symmetric for movement time and trajectory length. The results suggest that older adults retain the specialized functions of the non-dominant (right) hemisphere allowing them to program movement direction of a graphic aiming task when visual feedback is distorted.

Skill learning from kinesthetic feedback.

PubMed

Pinzon, David; Vega, Roberto; Sanchez, Yerly Paola; Zheng, Bin

2017-10-01

It is important for a surgeon to perform surgical tasks under appropriate guidance from visual and kinesthetic feedback. However, our knowledge on kinesthetic (muscle) memory and its role in learning motor skills remains elementary. To discover the effect of exclusive kinesthetic training on kinesthetic memory in both performance and learning. In Phase 1, a total of twenty participants duplicated five 2 dimensional movements of increasing complexity via passive kinesthetic guidance, without visual or auditory stimuli. Five participants were asked to repeat the task in the Phase 2 over a period of three weeks, for a total of nine sessions. Subjects accurately recalled movement direction using kinesthetic memory, but recalling movement length was less precise. Over the nine training sessions, error occurrence dropped after the sixth session. Muscle memory constructs the foundation for kinesthetic training. Knowledge gained helps surgeons learn skills from kinesthetic information in the condition where visual feedback is limited. Copyright © 2016 Elsevier Inc. All rights reserved.

Optimality and stability of intentional and unintentional actions: I. Origins of drifts in performance.

PubMed

Parsa, Behnoosh; Terekhov, Alexander; Zatsiorsky, Vladimir M; Latash, Mark L

2017-02-01

We address the nature of unintentional changes in performance in two papers. This first paper tested a hypothesis that unintentional changes in performance variables during continuous tasks without visual feedback are due to two processes. First, there is a drift of the referent coordinate for the salient performance variable toward the actual coordinate of the effector. Second, there is a drift toward minimum of a cost function. We tested this hypothesis in four-finger isometric pressing tasks that required the accurate production of a combination of total moment and total force with natural and modified finger involvement. Subjects performed accurate force-moment production tasks under visual feedback, and then visual feedback was removed for some or all of the salient variables. Analytical inverse optimization was used to compute a cost function. Without visual feedback, both force and moment drifted slowly toward lower absolute magnitudes. Over 15 s, the force drop could reach 20% of its initial magnitude while moment drop could reach 30% of its initial magnitude. Individual finger forces could show drifts toward both higher and lower forces. The cost function estimated using the analytical inverse optimization reduced its value as a consequence of the drift. We interpret the results within the framework of hierarchical control with referent spatial coordinates for salient variables at each level of the hierarchy combined with synergic control of salient variables. The force drift is discussed as a natural relaxation process toward states with lower potential energy in the physical (physiological) system involved in the task.

Optimality and stability of intentional and unintentional actions: I. Origins of drifts in performance

PubMed Central

Parsa, Behnoosh; Terekhov, Alexander; Zatsiorsky, Vladimir M.; Latash, Mark L.

2016-01-01

We address the nature of unintentional changes in performance in two papers. This first paper tested a hypothesis that unintentional changes in performance variables during continuous tasks without visual feedback are due to two processes. First, there is a drift of the referent coordinate for the salient performance variable toward the actual coordinate of the effector. Second, there is a drift toward minimum of a cost function. We tested this hypothesis in four-finger isometric pressing tasks that required the accurate production of a combination of total moment and total force with natural and modified finger involvement. Subjects performed accurate force/moment production tasks under visual feedback, and then visual feedback was removed for some or all of the salient variables. Analytical inverse optimization was used to compute a cost function. Without visual feedback, both force and moment drifted slowly toward lower absolute magnitudes. Over 15 s, the force drop could reach 20% of its initial magnitude while moment drop could reach 30% of its initial magnitude. Individual finger forces could show drifts toward both higher and lower forces. The cost function estimated using the analytical inverse optimization reduced its value as a consequence of the drift. We interpret the results within the framework of hierarchical control with referent spatial coordinates for salient variables at each level of the hierarchy combined with synergic control of salient variables. The force drift is discussed as a natural relaxation process toward states with lower potential energy in the physical (physiological) system involved in the task. PMID:27785549

Individual differences in learning correlate with modulation of brain activity induced by transcranial direct current stimulation

PubMed Central

Falcone, Brian; Wada, Atsushi; Parasuraman, Raja

2018-01-01

Transcranial direct current stimulation (tDCS) has been shown to enhance cognitive performance on a variety of tasks. It is hypothesized that tDCS enhances performance by affecting task related cortical excitability changes in networks underlying or connected to the site of stimulation facilitating long term potentiation. However, many recent studies have called into question the reliability and efficacy of tDCS to induce modulatory changes in brain activity. In this study, our goal is to investigate the individual differences in tDCS induced modulatory effects on brain activity related to the degree of enhancement in performance, providing insight into this lack of reliability. In accomplishing this goal, we used functional magnetic resonance imaging (fMRI) concurrently with tDCS stimulation (1 mA, 30 minutes duration) using a visual search task simulating real world conditions. The experiment consisted of three fMRI sessions: pre-training (no performance feedback), training (performance feedback which included response accuracy and target location and either real tDCS or sham stimulation given), and post-training (no performance feedback). The right posterior parietal cortex was selected as the site of anodal tDCS based on its known role in visual search and spatial attention processing. Our results identified a region in the right precentral gyrus, known to be involved with visual spatial attention and orienting, that showed tDCS induced task related changes in cortical excitability that were associated with individual differences in improved performance. This same region showed greater activity during the training session for target feedback of incorrect (target-error feedback) over correct trials for the tDCS stim over sham group indicating greater attention to target features during training feedback when trials were incorrect. These results give important insight into the nature of neural excitability induced by tDCS as it relates to variability in individual differences in improved performance shedding some light the apparent lack of reliability found in tDCS research. PMID:29782510

Voluntarily controlled but not merely observed visual feedback affects postural sway

PubMed Central

Asai, Tomohisa; Hiromitsu, Kentaro; Imamizu, Hiroshi

2018-01-01

Online stabilization of human standing posture utilizes multisensory afferences (e.g., vision). Whereas visual feedback of spontaneous postural sway can stabilize postural control especially when observers concentrate on their body and intend to minimize postural sway, the effect of intentional control of visual feedback on postural sway itself remains unclear. This study assessed quiet standing posture in healthy adults voluntarily controlling or merely observing visual feedback. The visual feedback (moving square) had either low or high gain and was either horizontally flipped or not. Participants in the voluntary-control group were instructed to minimize their postural sway while voluntarily controlling visual feedback, whereas those in the observation group were instructed to minimize their postural sway while merely observing visual feedback. As a result, magnified and flipped visual feedback increased postural sway only in the voluntary-control group. Furthermore, regardless of the instructions and feedback manipulations, the experienced sense of control over visual feedback positively correlated with the magnitude of postural sway. We suggest that voluntarily controlled, but not merely observed, visual feedback is incorporated into the feedback control system for posture and begins to affect postural sway. PMID:29682421

Calibration of visually guided reaching is driven by error-corrective learning and internal dynamics.

PubMed

Cheng, Sen; Sabes, Philip N

2007-04-01

The sensorimotor calibration of visually guided reaching changes on a trial-to-trial basis in response to random shifts in the visual feedback of the hand. We show that a simple linear dynamical system is sufficient to model the dynamics of this adaptive process. In this model, an internal variable represents the current state of sensorimotor calibration. Changes in this state are driven by error feedback signals, which consist of the visually perceived reach error, the artificial shift in visual feedback, or both. Subjects correct for > or =20% of the error observed on each movement, despite being unaware of the visual shift. The state of adaptation is also driven by internal dynamics, consisting of a decay back to a baseline state and a "state noise" process. State noise includes any source of variability that directly affects the state of adaptation, such as variability in sensory feedback processing, the computations that drive learning, or the maintenance of the state. This noise is accumulated in the state across trials, creating temporal correlations in the sequence of reach errors. These correlations allow us to distinguish state noise from sensorimotor performance noise, which arises independently on each trial from random fluctuations in the sensorimotor pathway. We show that these two noise sources contribute comparably to the overall magnitude of movement variability. Finally, the dynamics of adaptation measured with random feedback shifts generalizes to the case of constant feedback shifts, allowing for a direct comparison of our results with more traditional blocked-exposure experiments.

Detecting delay in visual feedback of an action as a monitor of self recognition.

PubMed

Hoover, Adria E N; Harris, Laurence R

2012-10-01

How do we distinguish "self" from "other"? The correlation between willing an action and seeing it occur is an important cue. We exploited the fact that this correlation needs to occur within a restricted temporal window in order to obtain a quantitative assessment of when a body part is identified as "self". We measured the threshold and sensitivity (d') for detecting a delay between movements of the finger (of both the dominant and non-dominant hands) and visual feedback as seen from four visual perspectives (the natural view, and mirror-reversed and/or inverted views). Each trial consisted of one presentation with minimum delay and another with a delay of between 33 and 150 ms. Participants indicated which presentation contained the delayed view. We varied the amount of efference copy available for this task by comparing performances for discrete movements and continuous movements. Discrete movements are associated with a stronger efference copy. Sensitivity to detect asynchrony between visual and proprioceptive information was significantly higher when movements were viewed from a "plausible" self perspective compared with when the view was reversed or inverted. Further, we found differences in performance between dominant and non-dominant hand finger movements across the continuous and single movements. Performance varied with the viewpoint from which the visual feedback was presented and on the efferent component such that optimal performance was obtained when the presentation was in the normal natural orientation and clear efferent information was available. Variations in sensitivity to visual/non-visual temporal incongruence with the viewpoint in which a movement is seen may help determine the arrangement of the underlying visual representation of the body.

Visual feedback attenuates mean concentric barbell velocity loss, and improves motivation, competitiveness, and perceived workload in male adolescent athletes.

PubMed

Weakley, Jonathon Js; Wilson, Kyle M; Till, Kevin; Read, Dale B; Darrall-Jones, Joshua; Roe, Gregory; Phibbs, Padraic J; Jones, Ben

2017-07-12

It is unknown whether instantaneous visual feedback of resistance training outcomes can enhance barbell velocity in younger athletes. Therefore, the purpose of this study was to quantify the effects of visual feedback on mean concentric barbell velocity in the back squat, and to identify changes in motivation, competitiveness, and perceived workload. In a randomised-crossover design (Feedback vs. Control) feedback of mean concentric barbell velocity was or was not provided throughout a set of 10 repetitions in the barbell back squat. Magnitude-based inferences were used to assess changes between conditions, with almost certainly greater differences in mean concentric velocity between the Feedback (0.70 ±0.04 m·s) and Control (0.65 ±0.05 m·s) observed. Additionally, individual repetition mean concentric velocity ranged from possibly (repetition number two: 0.79 ±0.04 vs. 0.78 ±0.04 m·s) to almost certainly (repetition number 10: 0.58 ±0.05 vs. 0.49 ±0.05 m·s) greater when provided feedback, while almost certain differences were observed in motivation, competitiveness, and perceived workload, respectively. Providing adolescent male athletes with visual kinematic information while completing resistance training is beneficial for the maintenance of barbell velocity during a training set, potentially enhancing physical performance. Moreover, these improvements were observed alongside increases in motivation, competitiveness and perceived workload providing insight into the underlying mechanisms responsible for the performance gains observed. Given the observed maintenance of barbell velocity during a training set, practitioners can use this technique to manipulate training outcomes during resistance training.

The effects of augmented visual feedback during balance training in Parkinson's disease: study design of a randomized clinical trial.

PubMed

van den Heuvel, Maarten R C; van Wegen, Erwin E H; de Goede, Cees J T; Burgers-Bots, Ingrid A L; Beek, Peter J; Daffertshofer, Andreas; Kwakkel, Gert

2013-10-04

Patients with Parkinson's disease often suffer from reduced mobility due to impaired postural control. Balance exercises form an integral part of rehabilitative therapy but the effectiveness of existing interventions is limited. Recent technological advances allow for providing enhanced visual feedback in the context of computer games, which provide an attractive alternative to conventional therapy. The objective of this randomized clinical trial is to investigate whether a training program capitalizing on virtual-reality-based visual feedback is more effective than an equally-dosed conventional training in improving standing balance performance in patients with Parkinson's disease. Patients with idiopathic Parkinson's disease will participate in a five-week balance training program comprising ten treatment sessions of 60 minutes each. Participants will be randomly allocated to (1) an experimental group that will receive balance training using augmented visual feedback, or (2) a control group that will receive balance training in accordance with current physical therapy guidelines for Parkinson's disease patients. Training sessions consist of task-specific exercises that are organized as a series of workstations. Assessments will take place before training, at six weeks, and at twelve weeks follow-up. The functional reach test will serve as the primary outcome measure supplemented by comprehensive assessments of functional balance, posturography, and electroencephalography. We hypothesize that balance training based on visual feedback will show greater improvements on standing balance performance than conventional balance training. In addition, we expect that learning new control strategies will be visible in the co-registered posturographic recordings but also through changes in functional connectivity.

Probing feedforward and feedback contributions to awareness with visual masking and transcranial magnetic stimulation

PubMed Central

Tapia, Evelina; Beck, Diane M.

2014-01-01

A number of influential theories posit that visual awareness relies not only on the initial, stimulus-driven (i.e., feedforward) sweep of activation but also on recurrent feedback activity within and between brain regions. These theories of awareness draw heavily on data from masking paradigms in which visibility of one stimulus is reduced due to the presence of another stimulus. More recently transcranial magnetic stimulation (TMS) has been used to study the temporal dynamics of visual awareness. TMS over occipital cortex affects performance on visual tasks at distinct time points and in a manner that is comparable to visual masking. We draw parallels between these two methods and examine evidence for the neural mechanisms by which visual masking and TMS suppress stimulus visibility. Specifically, both methods have been proposed to affect feedforward as well as feedback signals when applied at distinct time windows relative to stimulus onset and as a result modify visual awareness. Most recent empirical evidence, moreover, suggests that while visual masking and TMS impact stimulus visibility comparably, the processes these methods affect may not be as similar as previously thought. In addition to reviewing both masking and TMS studies that examine feedforward and feedback processes in vision, we raise questions to guide future studies and further probe the necessary conditions for visual awareness. PMID:25374548

The absence or temporal offset of visual feedback does not influence adaptation to novel movement dynamics.

PubMed

McKenna, Erin; Bray, Laurence C Jayet; Zhou, Weiwei; Joiner, Wilsaan M

2017-10-01

Delays in transmitting and processing sensory information require correctly associating delayed feedback to issued motor commands for accurate error compensation. The flexibility of this alignment between motor signals and feedback has been demonstrated for movement recalibration to visual manipulations, but the alignment dependence for adapting movement dynamics is largely unknown. Here we examined the effect of visual feedback manipulations on force-field adaptation. Three subject groups used a manipulandum while experiencing a lag in the corresponding cursor motion (0, 75, or 150 ms). When the offset was applied at the start of the session (continuous condition), adaptation was not significantly different between groups. However, these similarities may be due to acclimation to the offset before motor adaptation. We tested additional subjects who experienced the same delays concurrent with the introduction of the perturbation (abrupt condition). In this case adaptation was statistically indistinguishable from the continuous condition, indicating that acclimation to feedback delay was not a factor. In addition, end-point errors were not significantly different across the delay or onset conditions, but end-point correction (e.g., deceleration duration) was influenced by the temporal offset. As an additional control, we tested a group of subjects who performed without visual feedback and found comparable movement adaptation results. These results suggest that visual feedback manipulation (absence or temporal misalignment) does not affect adaptation to novel dynamics, independent of both acclimation and perceptual awareness. These findings could have implications for modeling how the motor system adjusts to errors despite concurrent delays in sensory feedback information. NEW & NOTEWORTHY A temporal offset between movement and distorted visual feedback (e.g., visuomotor rotation) influences the subsequent motor recalibration, but the effects of this offset for altered movement dynamics are largely unknown. Here we examined the influence of 1 ) delayed and 2 ) removed visual feedback on the adaptation to novel movement dynamics. These results contribute to understanding of the control strategies that compensate for movement errors when there is a temporal separation between motion state and sensory information. Copyright © 2017 the American Physiological Society.

Effect of Real-Time Feedback on Screw Placement Into Synthetic Cancellous Bone.

PubMed

Gustafson, Peter A; Geeslin, Andrew G; Prior, David M; Chess, Joseph L

2016-08-01

The objective of this study is to evaluate whether real-time torque feedback may reduce the occurrence of stripping when inserting nonlocking screws through fracture plates into synthetic cancellous bone. Five attending orthopaedic surgeons and 5 senior level orthopaedic residents inserted 8 screws in each phase. In phase I, screws were inserted without feedback simulating conventional techniques. In phase II, screws were driven with visual torque feedback. In phase III, screws were again inserted with conventional techniques. Comparison of these 3 phases with respect to screw insertion torque, surgeon rank, and perception of stripping was used to establish the effects of feedback. Seventy-three of 239 screws resulted in stripping. During the first phase, no feedback was provided and the overall strip rate was 41.8%; this decreased to 15% with visual feedback (P < 0.001) and returned to 35% when repeated without feedback. With feedback, a lower average torque was applied over a narrower torque distribution. Residents stripped 40.8% of screws compared with 20.2% for attending surgeons. Surgeons were poor at perceiving whether they stripped. Prevention and identification of stripping is influenced by surgeon perception of tactile sensation. This is significantly improved with utilization of real-time visual feedback of a torque versus roll curve. This concept of real-time feedback seems beneficial toward performance in synthetic cancellous bone and may lead to improved fixation in cancellous bone in a surgical setting.

Consistency of handwriting movements in dementia of the Alzheimer's type: a comparison with Huntington's and Parkinson's diseases.

PubMed

Slavin, M J; Phillips, J G; Bradshaw, J L; Hall, K A; Presnell, I

1999-01-01

Patients with dementia of the Alzheimer's type (DAT) and their matched controls wrote, on a computer graphics tablet, 4 consecutive, cursive letter 'l's, with varying levels of visual feedback: noninking pen and blank paper so that only the hand movements could be seen, noninking pen and lined paper to constrain their writing, goggles to occlude the lower visual field and eliminate all relevant visual feedback, and inking pen with full vision. The kinematic measures of stroke length, duration, and peak velocity were expressed in terms of consistency via a signal-to-noise ratio (M value of each parameter divided by its SD). Irrespective of medication or severity, DAT patients had writing strokes of significantly less consistent lengths than controls', and were disproportionately impaired by reduced visual feedback. Again irrespective of medication or severity, patients' strokes were of significantly less consistent duration, and significantly less consistent peak velocity than controls', independent of feedback conditions. Patients, unlike controls, frequently perseverated, producing more than 4 'l's, or multiple sets of responses, which was not differentially affected by level of visual feedback. The more variable performance of patients supports a degradation of the base motor program, and resembles that of Huntington's rather than Parkinson's disease patients. It may indeed reflect frontal rather than basal ganglia dysfunction.

A computational feedforward model predicts categorization of masked emotional body language for longer, but not for shorter, latencies.

PubMed

Stienen, Bernard M C; Schindler, Konrad; de Gelder, Beatrice

2012-07-01

Given the presence of massive feedback loops in brain networks, it is difficult to disentangle the contribution of feedforward and feedback processing to the recognition of visual stimuli, in this case, of emotional body expressions. The aim of the work presented in this letter is to shed light on how well feedforward processing explains rapid categorization of this important class of stimuli. By means of parametric masking, it may be possible to control the contribution of feedback activity in human participants. A close comparison is presented between human recognition performance and the performance of a computational neural model that exclusively modeled feedforward processing and was engineered to fulfill the computational requirements of recognition. Results show that the longer the stimulus onset asynchrony (SOA), the closer the performance of the human participants was to the values predicted by the model, with an optimum at an SOA of 100 ms. At short SOA latencies, human performance deteriorated, but the categorization of the emotional expressions was still above baseline. The data suggest that, although theoretically, feedback arising from inferotemporal cortex is likely to be blocked when the SOA is 100 ms, human participants still seem to rely on more local visual feedback processing to equal the model's performance.

Immediate Feedback on Accuracy and Performance: The Effects of Wireless Technology on Food Safety Tracking at a Distribution Center

ERIC Educational Resources Information Center

Goomas, David T.

2012-01-01

The effects of wireless ring scanners, which provided immediate auditory and visual feedback, were evaluated to increase the performance and accuracy of order selectors at a meat distribution center. The scanners not only increased performance and accuracy compared to paper pick sheets, but were also instrumental in immediate and accurate data…

Using visuo-kinetic virtual reality to induce illusory spinal movement: the MoOVi Illusion

PubMed Central

Smith, Ross T.; Hunter, Estin V.; Davis, Miles G.; Sterling, Michele; Moseley, G. Lorimer

2017-01-01

Background Illusions that alter perception of the body provide novel opportunities to target brain-based contributions to problems such as persistent pain. One example of this, mirror therapy, uses vision to augment perceived movement of a painful limb to treat pain. Since mirrors can’t be used to induce augmented neck or other spinal movement, we aimed to test whether such an illusion could be achieved using virtual reality, in advance of testing its potential therapeutic benefit. We hypothesised that perceived head rotation would depend on visually suggested movement. Method In a within-subjects repeated measures experiment, 24 healthy volunteers performed neck movements to 50o of rotation, while a virtual reality system delivered corresponding visual feedback that was offset by a factor of 50%–200%—the Motor Offset Visual Illusion (MoOVi)—thus simulating more or less movement than that actually occurring. At 50o of real-world head rotation, participants pointed in the direction that they perceived they were facing. The discrepancy between actual and perceived direction was measured and compared between conditions. The impact of including multisensory (auditory and visual) feedback, the presence of a virtual body reference, and the use of 360o immersive virtual reality with and without three-dimensional properties, was also investigated. Results Perception of head movement was dependent on visual-kinaesthetic feedback (p = 0.001, partial eta squared = 0.17). That is, altered visual feedback caused a kinaesthetic drift in the direction of the visually suggested movement. The magnitude of the drift was not moderated by secondary variables such as the addition of illusory auditory feedback, the presence of a virtual body reference, or three-dimensionality of the scene. Discussion Virtual reality can be used to augment perceived movement and body position, such that one can perform a small movement, yet perceive a large one. The MoOVi technique tested here has clear potential for assessment and therapy of people with spinal pain. PMID:28243537

Using visuo-kinetic virtual reality to induce illusory spinal movement: the MoOVi Illusion.

PubMed

Harvie, Daniel S; Smith, Ross T; Hunter, Estin V; Davis, Miles G; Sterling, Michele; Moseley, G Lorimer

2017-01-01

Illusions that alter perception of the body provide novel opportunities to target brain-based contributions to problems such as persistent pain. One example of this, mirror therapy, uses vision to augment perceived movement of a painful limb to treat pain. Since mirrors can't be used to induce augmented neck or other spinal movement, we aimed to test whether such an illusion could be achieved using virtual reality, in advance of testing its potential therapeutic benefit. We hypothesised that perceived head rotation would depend on visually suggested movement. In a within-subjects repeated measures experiment, 24 healthy volunteers performed neck movements to 50 o of rotation, while a virtual reality system delivered corresponding visual feedback that was offset by a factor of 50%-200%-the Motor Offset Visual Illusion (MoOVi)-thus simulating more or less movement than that actually occurring. At 50 o of real-world head rotation, participants pointed in the direction that they perceived they were facing. The discrepancy between actual and perceived direction was measured and compared between conditions. The impact of including multisensory (auditory and visual) feedback, the presence of a virtual body reference, and the use of 360 o immersive virtual reality with and without three-dimensional properties, was also investigated. Perception of head movement was dependent on visual-kinaesthetic feedback ( p  = 0.001, partial eta squared = 0.17). That is, altered visual feedback caused a kinaesthetic drift in the direction of the visually suggested movement. The magnitude of the drift was not moderated by secondary variables such as the addition of illusory auditory feedback, the presence of a virtual body reference, or three-dimensionality of the scene. Virtual reality can be used to augment perceived movement and body position, such that one can perform a small movement, yet perceive a large one. The MoOVi technique tested here has clear potential for assessment and therapy of people with spinal pain.

Audio-visual feedback improves the BCI performance in the navigational control of a humanoid robot

PubMed Central

Tidoni, Emmanuele; Gergondet, Pierre; Kheddar, Abderrahmane; Aglioti, Salvatore M.

2014-01-01

Advancement in brain computer interfaces (BCI) technology allows people to actively interact in the world through surrogates. Controlling real humanoid robots using BCI as intuitively as we control our body represents a challenge for current research in robotics and neuroscience. In order to successfully interact with the environment the brain integrates multiple sensory cues to form a coherent representation of the world. Cognitive neuroscience studies demonstrate that multisensory integration may imply a gain with respect to a single modality and ultimately improve the overall sensorimotor performance. For example, reactivity to simultaneous visual and auditory stimuli may be higher than to the sum of the same stimuli delivered in isolation or in temporal sequence. Yet, knowledge about whether audio-visual integration may improve the control of a surrogate is meager. To explore this issue, we provided human footstep sounds as audio feedback to BCI users while controlling a humanoid robot. Participants were asked to steer their robot surrogate and perform a pick-and-place task through BCI-SSVEPs. We found that audio-visual synchrony between footsteps sound and actual humanoid's walk reduces the time required for steering the robot. Thus, auditory feedback congruent with the humanoid actions may improve motor decisions of the BCI's user and help in the feeling of control over it. Our results shed light on the possibility to increase robot's control through the combination of multisensory feedback to a BCI user. PMID:24987350

Effect of vibrotactile feedback on an EMG-based proportional cursor control system.

PubMed

Li, Shunchong; Chen, Xingyu; Zhang, Dingguo; Sheng, Xinjun; Zhu, Xiangyang

2013-01-01

Surface electromyography (sEMG) has been introduced into the bio-mechatronics systems, however, most of them are lack of the sensory feedback. In this paper, the effect of vibrotactile feedback for a myoelectric cursor control system is investigated quantitatively. Simultaneous and proportional control signals are extracted from EMG using a muscle synergy model. Different types of feedback including vibrotactile feedback and visual feedback are added, assessed and compared with each other. The results show that vibrotactile feedback is capable of improving the performance of EMG-based human machine interface.

Improving lower limb weight distribution asymmetry during the squat using Nintendo Wii Balance Boards and real-time feedback.

PubMed

McGough, Rian; Paterson, Kade; Bradshaw, Elizabeth J; Bryant, Adam L; Clark, Ross A

2012-01-01

Weight-bearing asymmetry (WBA) may be detrimental to performance and could increase the risk of injury; however, detecting and reducing it is difficult in a field setting. This study assessed whether a portable and simple-to-use system designed with multiple Nintendo Wii Balance Boards (NWBBs) and customized software can be used to evaluate and improve WBA. Fifteen elite Australian Rules Footballers and 32 age-matched, untrained participants were tested for measures of WBA while squatting. The NWBB and customized software provided real-time visual feedback of WBA during half of the trials. Outcome measures included the mean mass difference (MMD) between limbs, interlimb symmetry index (SI), and percentage of time spent favoring a single limb (TFSL). Significant reductions in MMD (p = 0.028) and SI (p = 0.007) with visual feedback were observed for the entire group data. Subgroup analysis revealed significant reductions in MMD (p = 0.047) and SI (p = 0.026) with visual feedback in the untrained sample; however, the reductions in the trained sample were nonsignificant. The trained group showed significantly less WBA for TFSL under both visual conditions (no feedback: p = 0.015, feedback: p = 0.017). Correlation analysis revealed that participants with high levels of WBA had the greatest response to feedback (p < 0.001, ρ = 0.557). In conclusion, WBA exists in healthy untrained adults, and these asymmetries can be reduced using real-time visual feedback provided by an NWBB-based system. Healthy, well-trained professional athletes do not possess the same magnitude of WBA. Inexpensive, portable, and widely available gaming technology may be used to evaluate and improve WBA in clinical and sporting settings.

Spatiotemporal dynamics of brain activity during the transition from visually guided to memory-guided force control

PubMed Central

Poon, Cynthia; Chin-Cottongim, Lisa G.; Coombes, Stephen A.; Corcos, Daniel M.

2012-01-01

It is well established that the prefrontal cortex is involved during memory-guided tasks whereas visually guided tasks are controlled in part by a frontal-parietal network. However, the nature of the transition from visually guided to memory-guided force control is not as well established. As such, this study examines the spatiotemporal pattern of brain activity that occurs during the transition from visually guided to memory-guided force control. We measured 128-channel scalp electroencephalography (EEG) in healthy individuals while they performed a grip force task. After visual feedback was removed, the first significant change in event-related activity occurred in the left central region by 300 ms, followed by changes in prefrontal cortex by 400 ms. Low-resolution electromagnetic tomography (LORETA) was used to localize the strongest activity to the left ventral premotor cortex and ventral prefrontal cortex. A second experiment altered visual feedback gain but did not require memory. In contrast to memory-guided force control, altering visual feedback gain did not lead to early changes in the left central and midline prefrontal regions. Decreasing the spatial amplitude of visual feedback did lead to changes in the midline central region by 300 ms, followed by changes in occipital activity by 400 ms. The findings show that subjects rely on sensorimotor memory processes involving left ventral premotor cortex and ventral prefrontal cortex after the immediate transition from visually guided to memory-guided force control. PMID:22696535

Persuasive Performance Feedback: The Effect of Framing on Self-Efficacy

PubMed Central

Choe, Eun Kyoung; Lee, Bongshin; Munson, Sean; Pratt, Wanda; Kientz, Julie A.

2013-01-01

Self-monitoring technologies have proliferated in recent years as they offer excellent potential for promoting healthy behaviors. Although these technologies have varied ways of providing real-time feedback on a user’s current progress, we have a dearth of knowledge of the framing effects on the performance feedback these tools provide. With an aim to create influential, persuasive performance feedback that will nudge people toward healthy behaviors, we conducted an online experiment to investigate the effect of framing on an individual’s self-efficacy. We identified 3 different types of framing that can be applicable in presenting performance feedback: (1) the valence of performance (remaining vs. achieved framing), (2) presentation type (text-only vs. text with visual), and (3) data unit (raw vs. percentage). Results show that the achieved framing could lead to an increased perception of individual’s performance capabilities. This work provides empirical guidance for creating persuasive performance feedback, thereby helping people designing self-monitoring technologies to promote healthy behaviors. PMID:24551378

Persuasive performance feedback: the effect of framing on self-efficacy.

PubMed

Choe, Eun Kyoung; Lee, Bongshin; Munson, Sean; Pratt, Wanda; Kientz, Julie A

2013-01-01

Self-monitoring technologies have proliferated in recent years as they offer excellent potential for promoting healthy behaviors. Although these technologies have varied ways of providing real-time feedback on a user's current progress, we have a dearth of knowledge of the framing effects on the performance feedback these tools provide. With an aim to create influential, persuasive performance feedback that will nudge people toward healthy behaviors, we conducted an online experiment to investigate the effect of framing on an individual's self-efficacy. We identified 3 different types of framing that can be applicable in presenting performance feedback: (1) the valence of performance (remaining vs. achieved framing), (2) presentation type (text-only vs. text with visual), and (3) data unit (raw vs. percentage). Results show that the achieved framing could lead to an increased perception of individual's performance capabilities. This work provides empirical guidance for creating persuasive performance feedback, thereby helping people designing self-monitoring technologies to promote healthy behaviors.

An evaluation of end-point trajectory planning during skilled kicking.

PubMed

Ford, Paul; Hodges, Nicola J; Mark Williams, A

2009-01-01

There is evidence that actions are planned by anticipation of their external effects, with the strength of this effect being dependent on the amount of prior practice. In Experiment 1, skilled soccer players performed a kicking task under four conditions: planning in terms of an external action effect (i.e., ball trajectory) or in terms of body movements, either with or without visual error feedback. When feedback was withheld, a ball focus resulted in more accurate outcomes than a body focus. When visual feedback was allowed, there was no difference between these two conditions. In Experiment 2, both skilled and novice soccer players were tested with the addition of a control condition and in the absence of visual feedback. For both groups there was evidence that a ball focus was more beneficial for performance than a body focus, particularly in terms of movement kinematics where correlations across the joints were generally higher for body rather than ball planning. Most skilled participants reported that ball planning felt more normal than body planning. These experiments provide some evidence that actions are planned in terms of their external action effects, supporting the common-coding hypothesis of action planning.

Feature-Specific Organization of Feedback Pathways in Mouse Visual Cortex.

PubMed

Huh, Carey Y L; Peach, John P; Bennett, Corbett; Vega, Roxana M; Hestrin, Shaul

2018-01-08

Higher and lower cortical areas in the visual hierarchy are reciprocally connected [1]. Although much is known about how feedforward pathways shape receptive field properties of visual neurons, relatively little is known about the role of feedback pathways in visual processing. Feedback pathways are thought to carry top-down signals, including information about context (e.g., figure-ground segmentation and surround suppression) [2-5], and feedback has been demonstrated to sharpen orientation tuning of neurons in the primary visual cortex (V1) [6, 7]. However, the response characteristics of feedback neurons themselves and how feedback shapes V1 neurons' tuning for other features, such as spatial frequency (SF), remain largely unknown. Here, using a retrograde virus, targeted electrophysiological recordings, and optogenetic manipulations, we show that putatively feedback neurons in layer 5 (hereafter "L5 feedback") in higher visual areas, AL (anterolateral area) and PM (posteromedial area), display distinct visual properties in awake head-fixed mice. AL L5 feedback neurons prefer significantly lower SF (mean: 0.04 cycles per degree [cpd]) compared to PM L5 feedback neurons (0.15 cpd). Importantly, silencing AL L5 feedback reduced visual responses of V1 neurons preferring low SF (mean change in firing rate: -8.0%), whereas silencing PM L5 feedback suppressed responses of high-SF-preferring V1 neurons (-20.4%). These findings suggest that feedback connections from higher visual areas convey distinctly tuned visual inputs to V1 that serve to boost V1 neurons' responses to SF. Such like-to-like functional organization may represent an important feature of feedback pathways in sensory systems and in the nervous system in general. Copyright © 2017 Elsevier Ltd. All rights reserved.

Motivation in vigilance - Effects of self-evaluation and experimenter-controlled feedback.

NASA Technical Reports Server (NTRS)

Warm, J. S.; Kanfer, F. H.; Kuwada, S.; Clark, J. L.

1972-01-01

Vigilance experiments have been performed to study the relative efficiency of feedback operations in enhancing vigilance performance. Two feedback operations were compared - i.e., experimenter-controlled feedback in the form of knowledge of results (KR) regarding response times to signal detections, and subject-controlled feedback in the form of self-evaluation (SE) of response times to signal detections. The subjects responded to the aperiodic offset of a visual signal during a 1-hr vigil. Both feedback operations were found to enhance performance efficiency: subjects in the KR and SE conditions had faster response times than controls receiving no evaluative feedback. Moreover, the data of the KR and SE groups did not differ significantly from each other. The results are discussed in terms of the hypothesis that self-evaluation is a critical factor underlying the incentive value of KR in vigilance tasks.

Self-Management of Patient Body Position, Pose, and Motion Using Wide-Field, Real-Time Optical Measurement Feedback: Results of a Volunteer Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parkhurst, James M.; Price, Gareth J., E-mail: gareth.price@christie.nhs.uk; Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester

2013-12-01

Purpose: We present the results of a clinical feasibility study, performed in 10 healthy volunteers undergoing a simulated treatment over 3 sessions, to investigate the use of a wide-field visual feedback technique intended to help patients control their pose while reducing motion during radiation therapy treatment. Methods and Materials: An optical surface sensor is used to capture wide-area measurements of a subject's body surface with visualizations of these data displayed back to them in real time. In this study we hypothesize that this active feedback mechanism will enable patients to control their motion and help them maintain their setup posemore » and position. A capability hierarchy of 3 different level-of-detail abstractions of the measured surface data is systematically compared. Results: Use of the device enabled volunteers to increase their conformance to a reference surface, as measured by decreased variability across their body surfaces. The use of visual feedback also enabled volunteers to reduce their respiratory motion amplitude to 1.7 ± 0.6 mm compared with 2.7 ± 1.4 mm without visual feedback. Conclusions: The use of live feedback of their optically measured body surfaces enabled a set of volunteers to better manage their pose and motion when compared with free breathing. The method is suitable to be taken forward to patient studies.« less

Effects of acoustic feedback training in elite-standard Para-Rowing.

PubMed

Schaffert, Nina; Mattes, Klaus

2015-01-01

Assessment and feedback devices have been regularly used in technique training in high-performance sports. Biomechanical analysis is mainly visually based and so can exclude athletes with visual impairments. The aim of this study was to examine the effects of auditory feedback on mean boat speed during on-water training of visually impaired athletes. The German National Para-Rowing team (six athletes, mean ± s, age 34.8 ± 10.6 years, body mass 76.5 ± 13.5 kg, stature 179.3 ± 8.6 cm) participated in the study. Kinematics included boat acceleration and distance travelled, collected with Sofirow at two intensities of training. The boat acceleration-time traces were converted online into acoustic feedback and presented via speakers during rowing (sections with and without alternately). Repeated-measures within-participant factorial ANOVA showed greater boat speed with acoustic feedback than baseline (0.08 ± 0.01 m·s(-1)). The time structure of rowing cycles was improved (extended time of positive acceleration). Questioning of athletes showed acoustic feedback to be a supportive training aid as it provided important functional information about the boat motion independent of vision. It gave access for visually impaired athletes to biomechanical analysis via auditory information. The concept for adaptive athletes has been successfully integrated into the preparation for the Para-Rowing World Championships and Paralympics.

Effect of visual and tactile feedback on kinematic synergies in the grasping hand.

PubMed

Patel, Vrajeshri; Burns, Martin; Vinjamuri, Ramana

2016-08-01

The human hand uses a combination of feedforward and feedback mechanisms to accomplish high degree of freedom in grasp control efficiently. In this study, we used a synergy-based control model to determine the effect of sensory feedback on kinematic synergies in the grasping hand. Ten subjects performed two types of grasps: one that included feedback (real) and one without feedback (memory-guided), at two different speeds (rapid and natural). Kinematic synergies were extracted from rapid real and rapid memory-guided grasps using principal component analysis. Synergies extracted from memory-guided grasps revealed greater preservation of natural inter-finger relationships than those found in corresponding synergies extracted from real grasps. Reconstruction of natural real and natural memory-guided grasps was used to test performance and generalizability of synergies. A temporal analysis of reconstruction patterns revealed the differing contribution of individual synergies in real grasps versus memory-guided grasps. Finally, the results showed that memory-guided synergies could not reconstruct real grasps as accurately as real synergies could reconstruct memory-guided grasps. These results demonstrate how visual and tactile feedback affects a closed-loop synergy-based motor control system.

Effects of Visual Feedback Distortion on Gait Adaptation: Comparison of Implicit Visual Distortion Versus Conscious Modulation on Retention of Motor Learning.

PubMed

Kim, Seung-Jae; Ogilvie, Mitchell; Shimabukuro, Nathan; Stewart, Trevor; Shin, Joon-Ho

2015-09-01

Visual feedback can be used during gait rehabilitation to improve the efficacy of training. We presented a paradigm called visual feedback distortion; the visual representation of step length was manipulated during treadmill walking. Our prior work demonstrated that an implicit distortion of visual feedback of step length entails an unintentional adaptive process in the subjects' spatial gait pattern. Here, we investigated whether the implicit visual feedback distortion, versus conscious correction, promotes efficient locomotor adaptation that relates to greater retention of a task. Thirteen healthy subjects were studied under two conditions: (1) we implicitly distorted the visual representation of their gait symmetry over 14 min, and (2) with help of visual feedback, subjects were told to walk on the treadmill with the intent of attaining the gait asymmetry observed during the first implicit trial. After adaptation, the visual feedback was removed while subjects continued walking normally. Over this 6-min period, retention of preserved asymmetric pattern was assessed. We found that there was a greater retention rate during the implicit distortion trial than that of the visually guided conscious modulation trial. This study highlights the important role of implicit learning in the context of gait rehabilitation by demonstrating that training with implicit visual feedback distortion may produce longer lasting effects. This suggests that using visual feedback distortion could improve the effectiveness of treadmill rehabilitation processes by influencing the retention of motor skills.

Visuomotor adaptability in older adults with mild cognitive decline.

PubMed

Schaffert, Jeffrey; Lee, Chi-Mei; Neill, Rebecca; Bo, Jin

2017-02-01

The current study examined the augmentation of error feedback on visuomotor adaptability in older adults with varying degrees of cognitive decline (assessed by the Montreal Cognitive Assessment; MoCA). Twenty-three participants performed a center-out computerized visuomotor adaptation task when the visual feedback of their hand movement error was presented in a regular (ratio=1:1) or enhanced (ratio=1:2) error feedback schedule. Results showed that older adults with lower scores on the MoCA had less adaptability than those with higher MoCA scores during the regular feedback schedule. However, participants demonstrated similar adaptability during the enhanced feedback schedule, regardless of their cognitive ability. Furthermore, individuals with lower MoCA scores showed larger after-effects in spatial control during the enhanced schedule compared to the regular schedule, whereas individuals with higher MoCA scores displayed the opposite pattern. Additional neuro-cognitive assessments revealed that spatial working memory and processing speed were positively related to motor adaptability during the regular scheduled but negatively related to adaptability during the enhanced schedule. We argue that individuals with mild cognitive decline employed different adaptation strategies when encountering enhanced visual feedback, suggesting older adults with mild cognitive impairment (MCI) may benefit from enhanced visual error feedback during sensorimotor adaptation. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of feedback mode and task difficulty on quality of timing decisions in a zero-sum game.

PubMed

Tikuisis, Peter; Vartanian, Oshin; Mandel, David R

2014-09-01

The objective was to investigate the interaction between the mode of performance outcome feedback and task difficulty on timing decisions (i.e., when to act). Feedback is widely acknowledged to affect task performance. However, the extent to which feedback display mode and its impact on timing decisions is moderated by task difficulty remains largely unknown. Participants repeatedly engaged a zero-sum game involving silent duels with a computerized opponent and were given visual performance feedback after each engagement. They were sequentially tested on three different levels of task difficulty (low, intermediate, and high) in counterbalanced order. Half received relatively simple "inside view" binary outcome feedback, and the other half received complex "outside view" hit rate probability feedback. The key dependent variables were response time (i.e., time taken to make a decision) and survival outcome. When task difficulty was low to moderate, participants were more likely to learn and perform better from hit rate probability feedback than binary outcome feedback. However, better performance with hit rate feedback exacted a higher cognitive cost manifested by higher decision response time. The beneficial effect of hit rate probability feedback on timing decisions is partially moderated by task difficulty. Performance feedback mode should be judiciously chosen in relation to task difficulty for optimal performance in tasks involving timing decisions.

Develop feedback system for intelligent dynamic resource allocation to improve application performance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gentile, Ann C.; Brandt, James M.; Tucker, Thomas

2011-09-01

This report provides documentation for the completion of the Sandia Level II milestone 'Develop feedback system for intelligent dynamic resource allocation to improve application performance'. This milestone demonstrates the use of a scalable data collection analysis and feedback system that enables insight into how an application is utilizing the hardware resources of a high performance computing (HPC) platform in a lightweight fashion. Further we demonstrate utilizing the same mechanisms used for transporting data for remote analysis and visualization to provide low latency run-time feedback to applications. The ultimate goal of this body of work is performance optimization in the facemore » of the ever increasing size and complexity of HPC systems.« less

The Effect of Performance Feedback Provided to Student-Teachers Working with Multiple Disabilities

ERIC Educational Resources Information Center

Safak, Pinar; Yilmaz, Hatice Cansu; Demiryurek, Pinar; Dogus, Mustafa

2016-01-01

The aim of the study was to investigate the effect of performance feedback (PF) provided to student teachers working with students with multiple disabilities and visual impairment (MDVI) on their teaching skills. The study group of the research was composed of 11 student teachers attending to the final year of the Teaching Students with Visual…

Distinct Feedforward and Feedback Effects of Microstimulation in Visual Cortex Reveal Neural Mechanisms of Texture Segregation.

PubMed

Klink, P Christiaan; Dagnino, Bruno; Gariel-Mathis, Marie-Alice; Roelfsema, Pieter R

2017-07-05

The visual cortex is hierarchically organized, with low-level areas coding for simple features and higher areas for complex ones. Feedforward and feedback connections propagate information between areas in opposite directions, but their functional roles are only partially understood. We used electrical microstimulation to perturb the propagation of neuronal activity between areas V1 and V4 in monkeys performing a texture-segregation task. In both areas, microstimulation locally caused a brief phase of excitation, followed by inhibition. Both these effects propagated faithfully in the feedforward direction from V1 to V4. Stimulation of V4, however, caused little V1 excitation, but it did yield a delayed suppression during the late phase of visually driven activity. This suppression was pronounced for the V1 figure representation and weaker for background representations. Our results reveal functional differences between feedforward and feedback processing in texture segregation and suggest a specific modulating role for feedback connections in perceptual organization. Copyright © 2017 Elsevier Inc. All rights reserved.

Peripheral visual performance enhancement by neurofeedback training.

PubMed

Nan, Wenya; Wan, Feng; Lou, Chin Ian; Vai, Mang I; Rosa, Agostinho

2013-12-01

Peripheral visual performance is an important ability for everyone, and a positive inter-individual correlation is found between the peripheral visual performance and the alpha amplitude during the performance test. This study investigated the effect of alpha neurofeedback training on the peripheral visual performance. A neurofeedback group of 13 subjects finished 20 sessions of alpha enhancement feedback within 20 days. The peripheral visual performance was assessed by a new dynamic peripheral visual test on the first and last training day. The results revealed that the neurofeedback group showed significant enhancement of the peripheral visual performance as well as the relative alpha amplitude during the peripheral visual test. It was not the case in the non-neurofeedback control group, which performed the tests within the same time frame as the neurofeedback group but without any training sessions. These findings suggest that alpha neurofeedback training was effective in improving peripheral visual performance. To the best of our knowledge, this is the first study to show evidence for performance improvement in peripheral vision via alpha neurofeedback training.

Visual-perceptual mismatch in robotic surgery.

PubMed

Abiri, Ahmad; Tao, Anna; LaRocca, Meg; Guan, Xingmin; Askari, Syed J; Bisley, James W; Dutson, Erik P; Grundfest, Warren S

2017-08-01

The principal objective of the experiment was to analyze the effects of the clutch operation of robotic surgical systems on the performance of the operator. The relative coordinate system introduced by the clutch operation can introduce a visual-perceptual mismatch which can potentially have negative impact on a surgeon's performance. We also assess the impact of the introduction of additional tactile sensory information on reducing the impact of visual-perceptual mismatch on the performance of the operator. We asked 45 novice subjects to complete peg transfers using the da Vinci IS 1200 system with grasper-mounted, normal force sensors. The task involves picking up a peg with one of the robotic arms, passing it to the other arm, and then placing it on the opposite side of the view. Subjects were divided into three groups: aligned group (no mismatch), the misaligned group (10 cm z axis mismatch), and the haptics-misaligned group (haptic feedback and z axis mismatch). Each subject performed the task five times, during which the grip force, time of completion, and number of faults were recorded. Compared to the subjects that performed the tasks using a properly aligned controller/arm configuration, subjects with a single-axis misalignment showed significantly more peg drops (p = 0.011) and longer time to completion (p < 0.001). Additionally, it was observed that addition of tactile feedback helps reduce the negative effects of visual-perceptual mismatch in some cases. Grip force data recorded from grasper-mounted sensors showed no difference between the different groups. The visual-perceptual mismatch created by the misalignment of the robotic controls relative to the robotic arms has a negative impact on the operator of a robotic surgical system. Introduction of other sensory information and haptic feedback systems can help in potentially reducing this effect.

Social feedback processing from early to late adolescence: influence of sex, age, and attachment style

PubMed Central

Vrtička, Pascal; Sander, David; Anderson, Brittany; Badoud, Deborah; Eliez, Stephan; Debbané, Martin

2014-01-01

Objective The establishment of an accurate understanding of one's social context is a central developmental task during adolescence. A critical component of such development is to learn how to integrate the objective evaluation of one's behavior with the social response to the latter—here referred to as social feedback processing. Case report We measured brain activity by means of fMRI in 33 healthy adolescents (12–19 years old, 14 females). Participants played a difficult perceptual game with integrated verbal and visual feedback. Verbal feedback provided the participants with objective performance evaluation (won vs. lost). Visual feedback consisted of either smiling or angry faces, representing positive or negative social evaluations. Together, the combination of verbal and visual feedback gave rise to congruent versus incongruent social feedback combinations. In addition to assessing sex differences, we further tested for the effects of age and attachment style on social feedback processing. Results revealed that brain activity during social feedback processing was significantly modulated by sex, age, and attachment style in prefrontal cortical areas, ventral anterior cingulate cortex, anterior insula, caudate, and amygdala/hippocampus. We found indication for heightened activity during incongruent social feedback processing in females, older participants, and individuals with an anxious attachment style. Conversely, we observed stronger activity during processing of congruent social feedback in males and participants with an avoidant attachment style. Conclusion Our findings not only extend knowledge on the typical development of socio-emotional brain function during adolescence, but also provide first clues on how attachment insecurities, and particularly attachment avoidance, could interfere with the latter mechanisms. PMID:25328847

When they listen and when they watch: Pianists’ use of nonverbal audio and visual cues during duet performance

PubMed Central

Goebl, Werner

2015-01-01

Nonverbal auditory and visual communication helps ensemble musicians predict each other’s intentions and coordinate their actions. When structural characteristics of the music make predicting co-performers’ intentions difficult (e.g., following long pauses or during ritardandi), reliance on incoming auditory and visual signals may change. This study tested whether attention to visual cues during piano–piano and piano–violin duet performance increases in such situations. Pianists performed the secondo part to three duets, synchronizing with recordings of violinists or pianists playing the primo parts. Secondos’ access to incoming audio and visual signals and to their own auditory feedback was manipulated. Synchronization was most successful when primo audio was available, deteriorating when primo audio was removed and only cues from primo visual signals were available. Visual cues were used effectively following long pauses in the music, however, even in the absence of primo audio. Synchronization was unaffected by the removal of secondos’ own auditory feedback. Differences were observed in how successfully piano–piano and piano–violin duos synchronized, but these effects of instrument pairing were not consistent across pieces. Pianists’ success at synchronizing with violinists and other pianists is likely moderated by piece characteristics and individual differences in the clarity of cueing gestures used. PMID:26279610

Can motivation normalize working memory and task persistence in children with attention-deficit/hyperactivity disorder? The effects of money and computer-gaming.

PubMed

Dovis, Sebastiaan; Van der Oord, Saskia; Wiers, Reinout W; Prins, Pier J M

2012-07-01

Visual-spatial Working Memory (WM) is the most impaired executive function in children with Attention-Deficit/Hyperactivity Disorder (ADHD). Some suggest that deficits in executive functioning are caused by motivational deficits. However, there are no studies that investigate the effects of motivation on the visual-spatial WM of children with- and without ADHD. Studies examining this in executive functions other than WM, show inconsistent results. These inconsistencies may be related to differences in the reinforcement used. The effects of different reinforcers on WM performance were investigated in 30 children with ADHD and 31 non-ADHD controls. A visual-spatial WM task was administered in four reinforcement conditions: Feedback-only, 1 euro, 10 euros, and a computer-game version of the task. In the Feedback-only condition, children with ADHD performed worse on the WM measure than controls. Although incentives significantly improved the WM performance of children with ADHD, even the strongest incentives (10 euros and Gaming) were unable to normalize their performance. Feedback-only provided sufficient reinforcement for controls to reach optimal performance, while children with ADHD required extra reinforcement. Only children with ADHD showed a decrease in performance over time. Importantly, the strongest incentives (10 euros and Gaming) normalized persistence of performance in these children, whereas 1 euro had no such effect. Both executive and motivational deficits give rise to visual-spatial WM deficits in ADHD. Problems with task-persistence in ADHD result from motivational deficits. In ADHD-reinforcement studies and clinical practice (e.g., assessment), reinforcement intensity can be a confounding factor and should be taken into account. Gaming can be a cost-effective way to maximize performance in ADHD.

Reducing failures of working memory with performance feedback.

PubMed

Adam, Kirsten C S; Vogel, Edward K

2016-10-01

Fluctuations in attentional control can lead to failures of working memory (WM), in which the subject is no better than chance at reporting items from a recent display. In three experiments, we used a whole-report measure of visual WM to examine the impact of feedback on the rate of failures. In each experiment, subjects remembered an array of colored items across a blank delay, and then reported the identity of items using a whole-report procedure. In Experiment 1, we gave subjects simple feedback about the number of items they correctly identified at the end of each trial. In Experiment 2, we gave subjects additional information about the cumulative number of items correctly identified within each block. Finally, in Experiment 3, we gave subjects weighted feedback in which poor trials resulted in lost points and consistent successful performance received "streak" points. Surprisingly, simple feedback (Exp. 1) was ineffective at improving average performance or decreasing the rate of poor-performance trials. Simple cumulative feedback (Exp. 2) modestly decreased poor-performance trials (by 7 %). Weighted feedback produced the greatest benefits, decreasing the frequency of poor-performance trials by 28 % relative to baseline performance. This set of results demonstrates the usefulness of whole-report WM measures for investigating the effects of feedback on WM performance. Further, we showed that only a feedback structure that specifically discouraged lapses using negative feedback led to large reductions in WM failures.

Mirror reversal and visual rotation are learned and consolidated via separate mechanisms: recalibrating or learning de novo?

PubMed

Telgen, Sebastian; Parvin, Darius; Diedrichsen, Jörn

2014-10-08

Motor learning tasks are often classified into adaptation tasks, which involve the recalibration of an existing control policy (the mapping that determines both feedforward and feedback commands), and skill-learning tasks, requiring the acquisition of new control policies. We show here that this distinction also applies to two different visuomotor transformations during reaching in humans: Mirror-reversal (left-right reversal over a mid-sagittal axis) of visual feedback versus rotation of visual feedback around the movement origin. During mirror-reversal learning, correct movement initiation (feedforward commands) and online corrections (feedback responses) were only generated at longer latencies. The earliest responses were directed into a nonmirrored direction, even after two training sessions. In contrast, for visual rotation learning, no dependency of directional error on reaction time emerged, and fast feedback responses to visual displacements of the cursor were immediately adapted. These results suggest that the motor system acquires a new control policy for mirror reversal, which initially requires extra processing time, while it recalibrates an existing control policy for visual rotations, exploiting established fast computational processes. Importantly, memory for visual rotation decayed between sessions, whereas memory for mirror reversals showed offline gains, leading to better performance at the beginning of the second session than in the end of the first. With shifts in time-accuracy tradeoff and offline gains, mirror-reversal learning shares common features with other skill-learning tasks. We suggest that different neuronal mechanisms underlie the recalibration of an existing versus acquisition of a new control policy and that offline gains between sessions are a characteristic of latter. Copyright © 2014 the authors 0270-6474/14/3413768-12$15.00/0.

Reward and Visual Feedback Relative to the Performance and Mechanical Efficiency of High School Girls in the Standing Broad Jump.

ERIC Educational Resources Information Center

Zebas, Carole J.

This study focuses on changes occurring in selected mechanical components of high school girls performing the standing broad jump, and collects data pertaining to the effects of monetary reward and videotape feedback upon the following components: (a) distance jumped, (b) maximum angle of knee flexion, (c) maximum angle of hip flexion, (d) hip…

A virtual reality-based method of decreasing transmission time of visual feedback for a tele-operative robotic catheter operating system.

PubMed

Guo, Jin; Guo, Shuxiang; Tamiya, Takashi; Hirata, Hideyuki; Ishihara, Hidenori

2016-03-01

An Internet-based tele-operative robotic catheter operating system was designed for vascular interventional surgery, to afford unskilled surgeons the opportunity to learn basic catheter/guidewire skills, while allowing experienced physicians to perform surgeries cooperatively. Remote surgical procedures, limited by variable transmission times for visual feedback, have been associated with deterioration in operability and vascular wall damage during surgery. At the patient's location, the catheter shape/position was detected in real time and converted into three-dimensional coordinates in a world coordinate system. At the operation location, the catheter shape was reconstructed in a virtual-reality environment, based on the coordinates received. The data volume reduction significantly reduced visual feedback transmission times. Remote transmission experiments, conducted over inter-country distances, demonstrated the improved performance of the proposed prototype. The maximum error for the catheter shape reconstruction was 0.93 mm and the transmission time was reduced considerably. The results were positive and demonstrate the feasibility of remote surgery using conventional network infrastructures. Copyright © 2015 John Wiley & Sons, Ltd.

Visual-perceptual-kinesthetic inputs on influencing writing performances in children with handwriting difficulties.

PubMed

Tse, Linda F L; Thanapalan, Kannan C; Chan, Chetwyn C H

2014-02-01

This study investigated the role of visual-perceptual input in writing Chinese characters among senior school-aged children who had handwriting difficulties (CHD). The participants were 27 CHD (9-11 years old) and 61 normally developed control. There were three writing conditions: copying, and dictations with or without visual feedback. The motor-free subtests of the Developmental Test of Visual Perception (DTVP-2) were conducted. The CHD group showed significantly slower mean speeds of character production and less legibility of produced characters than the control group in all writing conditions (ps<0.001). There were significant deteriorations in legibility from copying to dictation without visual feedback. Nevertheless, the Group by Condition interaction effect was not statistically significant. Only position in space of DTVP-2 was significantly correlated with the legibility among CHD (r=-0.62, p=0.001). Poor legibility seems to be related to the less-intact spatial representation of the characters in working memory, which can be rectified by viewing the characters during writing. Visual feedback regarding one's own actions in writing can also improve legibility of characters among these children. Copyright © 2013 Elsevier Ltd. All rights reserved.

Electrocardiographic anxiety profiles improve speech anxiety.

PubMed

Kim, Pyoung Won; Kim, Seung Ae; Jung, Keun-Hwa

2012-12-01

The present study was to set out in efforts to determine the effect of electrocardiographic (ECG) feedback on the performance in speech anxiety. Forty-six high school students participated in a speech performance educational program. They were randomly divided into two groups, an experimental group with ECG feedback (N = 21) and a control group (N = 25). Feedback was given with video recording in the control, whereas in the experimental group, an additional ECG feedback was provided. Speech performance was evaluated by the Korean Broadcasting System (KBS) speech ability test, which determines the 10 different speaking categories. ECG was recorded during rest and speech, together with a video recording of the speech performance. Changes in R-R intervals were used to reflect anxiety profiles. Three trials were performed for 3-week program. Results showed that the subjects with ECG feedback revealed a significant improvement in speech performance and anxiety states, which compared to those in the control group. These findings suggest that visualization of the anxiety profile feedback with ECG can be a better cognitive therapeutic strategy in speech anxiety.

Seeing the hand while reaching speeds up on-line responses to a sudden change in target position

PubMed Central

Reichenbach, Alexandra; Thielscher, Axel; Peer, Angelika; Bülthoff, Heinrich H; Bresciani, Jean-Pierre

2009-01-01

Goal-directed movements are executed under the permanent supervision of the central nervous system, which continuously processes sensory afferents and triggers on-line corrections if movement accuracy seems to be compromised. For arm reaching movements, visual information about the hand plays an important role in this supervision, notably improving reaching accuracy. Here, we tested whether visual feedback of the hand affects the latency of on-line responses to an external perturbation when reaching for a visual target. Two types of perturbation were used: visual perturbation consisted in changing the spatial location of the target and kinesthetic perturbation in applying a force step to the reaching arm. For both types of perturbation, the hand trajectory and the electromyographic (EMG) activity of shoulder muscles were analysed to assess whether visual feedback of the hand speeds up on-line corrections. Without visual feedback of the hand, on-line responses to visual perturbation exhibited the longest latency. This latency was reduced by about 10% when visual feedback of the hand was provided. On the other hand, the latency of on-line responses to kinesthetic perturbation was independent of the availability of visual feedback of the hand. In a control experiment, we tested the effect of visual feedback of the hand on visual and kinesthetic two-choice reaction times – for which coordinate transformation is not critical. Two-choice reaction times were never facilitated by visual feedback of the hand. Taken together, our results suggest that visual feedback of the hand speeds up on-line corrections when the position of the visual target with respect to the body must be re-computed during movement execution. This facilitation probably results from the possibility to map hand- and target-related information in a common visual reference frame. PMID:19675067

Effect of an auditory feedback substitution, tactilo-kinesthetic, or visual feedback on kinematics of pouring water from kettle into cup.

PubMed

Portnoy, Sigal; Halaby, Orli; Dekel-Chen, Dotan; Dierick, Frédéric

2015-11-01

Pouring hot water from a kettle into a cup may prove a hazardous task, especially for the elderly or the visually-impaired. Individuals with deteriorating eyesight may endanger their hands by performing this task with both hands, relaying on tactilo-kinesthetic feedback (TKF). Auditory feedback (AF) may allow them to perform the task singlehandedly, thereby reducing the risk for injury. However since relying on an AF is not intuitive and requires practice, we aimed to determine if AF supplied during the task of pouring water can be used naturally as visual feedback (VF) following practice. For this purpose, we quantified, in young healthy sighted subjects (n = 20), the performance and kinematics of pouring water in the presence of three isolated feedbacks: visual, tactilo-kinesthetic, or auditory. There were no significant differences between the weights of spilled water in the AF condition compared to the TKF condition in the first, fifth or thirteenth trials. The subjectively-reported difficulty levels of using the TKF and the AF were significantly reduced between the first and thirteenth trials for both TKF (p = 0.01) and AF (p = 0.001). Trunk rotation during the first trial using the TKF was significantly lower than the trunk rotation while using VF. Also, shoulder adduction during the first trial using the TKF was significantly higher than the shoulder adduction while using the VF. During the AF trials, the median travel distance of the tip of the kettle was significantly reduced in the first trials so that in the thirtieth trial it did not differ significantly from the median travel distance during the thirtieth trial using TKF and VF. The maximal velocity of the tip of the kettle was constant for each of the feedback conditions but was higher in 10 cm s(-1) using VF than TKF, which was higher in 10 cm s(-1) from using AF. The smoothness of movement of the TKF and AF conditions, expressed by the normalized jerk score (NJSM), was one and two orders of magnitude higher from the VF, respectively. The median NJSM then decreased significantly by the fifth trial. Monitoring in-house activity via motion capture and classification of movements, i.e. liquid pouring, can assist with daily activities via AF. As a built-in feature in a smart home, this task-specific AF may prevent burn injuries of the visually-impaired. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Visual feedback training using WII Fit improves balance in Parkinson's disease.

PubMed

Zalecki, Tomasz; Gorecka-Mazur, Agnieszka; Pietraszko, Wojciech; Surowka, Artur D; Novak, Pawel; Moskala, Marek; Krygowska-Wajs, Anna

2013-01-01

Postural instability including imbalance is the most disabling long term problem in Parkinson's disease (PD) that does not respond to pharmacotherapy. This study aimed at investigating the effectiveness of a novel visual-feedback training method, using Wii Fit balance board in improving balance in patients with PD. Twenty four patients with moderate PD were included in the study which comprised of a 6-week home-based balance training program using Nintendo Wii Fit and balance board. The PD patients significantly improved their results in Berg Balance Scale, Tinnet's Performance-Oriented Mobility Assessment, Timed Up-and-Go, Sit-to-stand test, 10-Meter Walk test and Activities-specific Balance Confidence scale at the end of the programme. This study suggests that visual feedback training using Wii-Fit with balance board could improve dynamic and functional balance as well as motor disability in PD patients.

The influence of visual feedback from the recent past on the programming of grip aperture is grasp-specific, shared between hands, and mediated by sensorimotor memory not task set.

PubMed

Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

2015-05-01

Goal-directed movements, such as reaching out to grasp an object, are necessarily constrained by the spatial properties of the target such as its size, shape, and position. For example, during a reach-to-grasp movement, the peak width of the aperture formed by the thumb and fingers in flight (peak grip aperture, PGA) is linearly related to the target's size. Suppressing vision throughout the movement (visual open loop) has a small though significant effect on this relationship. Visual open loop conditions also produce a large increase in the PGA compared to when vision is available throughout the movement (visual closed loop). Curiously, this differential effect of the availability of visual feedback is influenced by the presentation order: the difference in PGA between closed- and open-loop trials is smaller when these trials are intermixed (an effect we have called 'homogenization'). Thus, grasping movements are affected not only by the availability of visual feedback (closed loop or open loop) but also by what happened on the previous trial. It is not clear, however, whether this carry-over effect is mediated through motor (or sensorimotor) memory or through the interference of different task sets for closed-loop and open-loop feedback that determine when the movements are fully specified. We reasoned that sensorimotor memory, but not a task set for closed and open loop feedback, would be specific to the type of response. We tested this prediction in a condition in which pointing to targets was alternated with grasping those same targets. Critically, in this condition, when pointing was performed in open loop, grasping was always performed in closed loop (and vice versa). Despite the fact that closed- and open-loop trials were alternating in this condition, we found no evidence for homogenization of the PGA. Homogenization did occur, however, in a follow-up experiment in which grasping movements and visual feedback were alternated between the left and the right hand, indicating that sensorimotor (or motor) memory can operate both within and between hands when the response type is kept the same. In a final experiment, we ruled out the possibility that simply alternating the hand used to perform the grasp interferes with motor or sensorimotor memory. We did this by showing that when the hand was alternated within a block of exclusively closed- or open-loop trials, homogenization of the PGA did not occur. Taken together, the results suggest that (1) interference from simply switching between task sets for closed or open-loop feedback or from switching between the hands cannot account homogenization in the PGA and that (2) the programming and execution of grasps can borrow not only from grasping movements executed in the past by the same hand, but also from grasping movements executed with the other hand. Copyright © 2015 Elsevier B.V. All rights reserved.

Walking Speed Influences the Effects of Implicit Visual Feedback Distortion on Modulation of Gait Symmetry

PubMed Central

Maestas, Gabrielle; Hu, Jiyao; Trevino, Jessica; Chunduru, Pranathi; Kim, Seung-Jae; Lee, Hyunglae

2018-01-01

The use of visual feedback in gait rehabilitation has been suggested to promote recovery of locomotor function by incorporating interactive visual components. Our prior work demonstrated that visual feedback distortion of changes in step length symmetry entails an implicit or unconscious adaptive process in the subjects’ spatial gait patterns. We investigated whether the effect of the implicit visual feedback distortion would persist at three different walking speeds (slow, self-preferred and fast speeds) and how different walking speeds would affect the amount of adaption. In the visual feedback distortion paradigm, visual vertical bars portraying subjects’ step lengths were distorted so that subjects perceived their step lengths to be asymmetric during testing. Measuring the adjustments in step length during the experiment showed that healthy subjects made spontaneous modulations away from actual symmetry in response to the implicit visual distortion, no matter the walking speed. In all walking scenarios, the effects of implicit distortion became more significant at higher distortion levels. In addition, the amount of adaptation induced by the visual distortion was significantly greater during walking at preferred or slow speed than at the fast speed. These findings indicate that although a link exists between supraspinal function through visual system and human locomotion, sensory feedback control for locomotion is speed-dependent. Ultimately, our results support the concept that implicit visual feedback can act as a dominant form of feedback in gait modulation, regardless of speed. PMID:29632481

Does visual feedback during walking result in similar improvements in trunk control for young and older healthy adults?

PubMed

Anson, Eric; Rosenberg, Russell; Agada, Peter; Kiemel, Tim; Jeka, John

2013-11-26

Most current applications of visual feedback to improve postural control are limited to a fixed base of support and produce mixed results regarding improved postural control and transfer to functional tasks. Currently there are few options available to provide visual feedback regarding trunk motion while walking. We have developed a low cost platform to provide visual feedback of trunk motion during walking. Here we investigated whether augmented visual position feedback would reduce trunk movement variability in both young and older healthy adults. The subjects who participated were 10 young and 10 older adults. Subjects walked on a treadmill under conditions of visual position feedback and no feedback. The visual feedback consisted of anterior-posterior (AP) and medial-lateral (ML) position of the subject's trunk during treadmill walking. Fourier transforms of the AP and ML trunk kinematics were used to calculate power spectral densities which were integrated as frequency bins "below the gait cycle" and "gait cycle and above" for analysis purposes. Visual feedback reduced movement power at very low frequencies for lumbar and neck translation but not trunk angle in both age groups. At very low frequencies of body movement, older adults had equivalent levels of movement variability with feedback as young adults without feedback. Lower variability was specific to translational (not angular) trunk movement. Visual feedback did not affect any of the measured lower extremity gait pattern characteristics of either group, suggesting that changes were not invoked by a different gait pattern. Reduced translational variability while walking on the treadmill reflects more precise control maintaining a central position on the treadmill. Such feedback may provide an important technique to augment rehabilitation to minimize body translation while walking. Individuals with poor balance during walking may benefit from this type of training to enhance path consistency during over-ground locomotion.

Using real-time ultrasound imaging as adjunct teaching tools to enhance physical therapist students' ability and confidence to perform traction of the knee joint.

PubMed

Markowski, Alycia; Watkins, Maureen K; Burnett, Todd; Ho, Melissa; Ling, Michael

2018-04-01

Often, physical therapy students struggle with the skill and the confidence to perform manual techniques for musculoskeletal examination. Current teaching methods lack concurrent objective feedback. Real-time ultrasound imaging (RTUI) has the advantage of generating visualization of anatomical structures in real-time in an efficient and safe manner. We hypothesize that the use of RTUI to augment teaching with concurrent objective visual feedback will result in students' improved ability to create a change in joint space when performing a manual knee traction and higher confidence scores. Eighty-six students were randomly allocated to a control or an experimental group. All participants received baseline instructions on how to perform knee traction. The control group received standardized lab instruction (visual, video, and instructor/partner feedback). The experimental group received standardized lab instruction augmented with RTUI feedback. Pre-data and post-data collection consisted of measuring participants' ability to create changes in joint space when performing knee traction, a confidence survey evaluating perceived ability and a reflection paper. Joint space changes between groups were compared using a paired t-test. Surveys were analyzed with descriptive statistics and compared using Wilcoxon Rank Sum and for the reflection papers, themes were identified and descriptive statistics reported. Although there were no statistically significant differences between the control and the experimental group, overall scores improved. Qualitative data suggests students found the use of ultrasound imaging beneficial and would like more exposure. This novel approach to teaching knee traction with RTUI has potential and may be a basis for further studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Closed-Loop Hybrid Gaze Brain-Machine Interface Based Robotic Arm Control with Augmented Reality Feedback

PubMed Central

Zeng, Hong; Wang, Yanxin; Wu, Changcheng; Song, Aiguo; Liu, Jia; Ji, Peng; Xu, Baoguo; Zhu, Lifeng; Li, Huijun; Wen, Pengcheng

2017-01-01

Brain-machine interface (BMI) can be used to control the robotic arm to assist paralysis people for performing activities of daily living. However, it is still a complex task for the BMI users to control the process of objects grasping and lifting with the robotic arm. It is hard to achieve high efficiency and accuracy even after extensive trainings. One important reason is lacking of sufficient feedback information for the user to perform the closed-loop control. In this study, we proposed a method of augmented reality (AR) guiding assistance to provide the enhanced visual feedback to the user for a closed-loop control with a hybrid Gaze-BMI, which combines the electroencephalography (EEG) signals based BMI and the eye tracking for an intuitive and effective control of the robotic arm. Experiments for the objects manipulation tasks while avoiding the obstacle in the workspace are designed to evaluate the performance of our method for controlling the robotic arm. According to the experimental results obtained from eight subjects, the advantages of the proposed closed-loop system (with AR feedback) over the open-loop system (with visual inspection only) have been verified. The number of trigger commands used for controlling the robotic arm to grasp and lift the objects with AR feedback has reduced significantly and the height gaps of the gripper in the lifting process have decreased more than 50% compared to those trials with normal visual inspection only. The results reveal that the hybrid Gaze-BMI user can benefit from the information provided by the AR interface, improving the efficiency and reducing the cognitive load during the grasping and lifting processes. PMID:29163123

Task clarification, performance feedback, and social praise: Procedures for improving the customer service of bank tellers

PubMed Central

Crowell, Charles R.; Anderson, D. Chris; Abel, Dawn M.; Sergio, Joseph P.

1988-01-01

Customer service for bank tellers was defined in terms of 11 verbal behavior categories. An audio-recording system was used to track the occurrence of behaviors in these categories for six retail banking tellers. Three behavior management interventions (task clarification, performance feedback, and social praise), applied in sequence, were designed to improve overall teller performance with regard to the behavioral categories targeted. Clarification was accomplished by providing clear delineation of the various target categories, with specific examples of the behaviors in each. Feedback entailed presentation of ongoing verbal and visual information regarding teller performance. Praise consisted of verbal recognition of teller performance by branch managers. Results showed that clarification effects emerged quickly, producing an overall increase in desired behaviors of 12% over baseline. Feedback and praise effects occurred more gradually, resulting in overall increases of 6% and 7%, respectively. A suspension of all procedures led to a decline in overall performance, whereas reinstatement of feedback and praise was again accompanied by performance improvement. These findings extend the generality of behavior management applications and help to distinguish between possible antecedent and consequent effects of performance feedback. PMID:16795713

Interface Prostheses With Classifier-Feedback-Based User Training.

PubMed

Fang, Yinfeng; Zhou, Dalin; Li, Kairu; Liu, Honghai

2017-11-01

It is evident that user training significantly affects performance of pattern-recognition-based myoelectric prosthetic device control. Despite plausible classification accuracy on offline datasets, online accuracy usually suffers from the changes in physiological conditions and electrode displacement. The user ability in generating consistent electromyographic (EMG) patterns can be enhanced via proper user training strategies in order to improve online performance. This study proposes a clustering-feedback strategy that provides real-time feedback to users by means of a visualized online EMG signal input as well as the centroids of the training samples, whose dimensionality is reduced to minimal number by dimension reduction. Clustering feedback provides a criterion that guides users to adjust motion gestures and muscle contraction forces intentionally. The experiment results have demonstrated that hand motion recognition accuracy increases steadily along the progress of the clustering-feedback-based user training, while conventional classifier-feedback methods, i.e., label feedback, hardly achieve any improvement. The result concludes that the use of proper classifier feedback can accelerate the process of user training, and implies prosperous future for the amputees with limited or no experience in pattern-recognition-based prosthetic device manipulation.It is evident that user training significantly affects performance of pattern-recognition-based myoelectric prosthetic device control. Despite plausible classification accuracy on offline datasets, online accuracy usually suffers from the changes in physiological conditions and electrode displacement. The user ability in generating consistent electromyographic (EMG) patterns can be enhanced via proper user training strategies in order to improve online performance. This study proposes a clustering-feedback strategy that provides real-time feedback to users by means of a visualized online EMG signal input as well as the centroids of the training samples, whose dimensionality is reduced to minimal number by dimension reduction. Clustering feedback provides a criterion that guides users to adjust motion gestures and muscle contraction forces intentionally. The experiment results have demonstrated that hand motion recognition accuracy increases steadily along the progress of the clustering-feedback-based user training, while conventional classifier-feedback methods, i.e., label feedback, hardly achieve any improvement. The result concludes that the use of proper classifier feedback can accelerate the process of user training, and implies prosperous future for the amputees with limited or no experience in pattern-recognition-based prosthetic device manipulation.

A Pilot Study Assessing Performance and Visual Attention of Teenagers with ASD in a Novel Adaptive Driving Simulator.

PubMed

Wade, Joshua; Weitlauf, Amy; Broderick, Neill; Swanson, Amy; Zhang, Lian; Bian, Dayi; Sarkar, Medha; Warren, Zachary; Sarkar, Nilanjan

2017-11-01

Individuals with Autism Spectrum Disorder (ASD), compared to typically-developed peers, may demonstrate behaviors that are counter to safe driving. The current work examines the use of a novel simulator in two separate studies. Study 1 demonstrates statistically significant performance differences between individuals with (N = 7) and without ASD (N = 7) with regards to the number of turning-related driving errors (p < 0.01). Study 2 shows that both the performance-based feedback group (N = 9) and combined performance- and gaze-sensitive feedback group (N = 8) achieved statistically significant reductions in driving errors following training (p < 0.05). These studies are the first to present results of fine-grained measures of visual attention of drivers and an adaptive driving intervention for individuals with ASD.

Problem solving in great apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, and Pongo abelii): the effect of visual feedback.

PubMed

Völter, Christoph J; Call, Josep

2012-09-01

What kind of information animals use when solving problems is a controversial topic. Previous research suggests that, in some situations, great apes prefer to use causally relevant cues over arbitrary ones. To further examine to what extent great apes are able to use information about causal relations, we presented three different puzzle box problems to the four nonhuman great ape species. Of primary interest here was a comparison between one group of apes that received visual access to the functional mechanisms of the puzzle boxes and one group that did not. Apes' performance in the first two, less complex puzzle boxes revealed that they are able to solve such problems by means of trial-and-error learning, requiring no information about the causal structure of the problem. However, visual inspection of the functional mechanisms of the puzzle boxes reduced the amount of time needed to solve the problems. In the case of the most complex problem, which required the use of a crank, visual feedback about what happened when the handle of the crank was turned was necessary for the apes to solve the task. Once the solution was acquired, however, visual feedback was no longer required. We conclude that visual feedback about the consequences of their actions helps great apes to solve complex problems. As the crank task matches the basic requirements of vertical string pulling in birds, the present results are discussed in light of recent findings with corvids.

Manipulating the fidelity of lower extremity visual feedback to identify obstacle negotiation strategies in immersive virtual reality.

PubMed

Kim, Aram; Zhou, Zixuan; Kretch, Kari S; Finley, James M

2017-07-01

The ability to successfully navigate obstacles in our environment requires integration of visual information about the environment with estimates of our body's state. Previous studies have used partial occlusion of the visual field to explore how information about the body and impending obstacles are integrated to mediate a successful clearance strategy. However, because these manipulations often remove information about both the body and obstacle, it remains to be seen how information about the lower extremities alone is utilized during obstacle crossing. Here, we used an immersive virtual reality (VR) interface to explore how visual feedback of the lower extremities influences obstacle crossing performance. Participants wore a head-mounted display while walking on treadmill and were instructed to step over obstacles in a virtual corridor in four different feedback trials. The trials involved: (1) No visual feedback of the lower extremities, (2) an endpoint-only model, (3) a link-segment model, and (4) a volumetric multi-segment model. We found that the volumetric model improved success rate, placed their trailing foot before crossing and leading foot after crossing more consistently, and placed their leading foot closer to the obstacle after crossing compared to no model. This knowledge is critical for the design of obstacle negotiation tasks in immersive virtual environments as it may provide information about the fidelity necessary to reproduce ecologically valid practice environments.

Novel virtual reality system integrating online self-face viewing and mirror visual feedback for stroke rehabilitation: rationale and feasibility.

PubMed

Shiri, Shimon; Feintuch, Uri; Lorber-Haddad, Adi; Moreh, Elior; Twito, Dvora; Tuchner-Arieli, Maya; Meiner, Zeev

2012-01-01

To introduce the rationale of a novel virtual reality system based on self-face viewing and mirror visual feedback, and to examine its feasibility as a rehabilitation tool for poststroke patients. A novel motion capture virtual reality system integrating online self-face viewing and mirror visual feedback has been developed for stroke rehabilitation.The system allows the replacement of the impaired arm by a virtual arm. Upon making small movements of the paretic arm, patients view themselves virtually performing healthy full-range movements. A sample of 6 patients in the acute poststroke phase received the virtual reality treatment concomitantly with conservative rehabilitation treatment. Feasibility was assessed during 10 sessions for each participant. All participants succeeded in operating the system, demonstrating its feasibility in terms of adherence and improvement in task performance. Patients' performance within the virtual environment and a set of clinical-functional measures recorded before the virtual reality treatment, at 1 week, and after 3 months indicated neurological status and general functioning improvement. These preliminary results indicate that this newly developed virtual reality system is safe and feasible. Future randomized controlled studies are required to assess whether this system has beneficial effects in terms of enhancing upper limb function and quality of life in poststroke patients.

The interaction of respiration and visual feedback on the control of force and neural activation of the agonist muscle

PubMed Central

Baweja, Harsimran S.; Patel, Bhavini K.; Neto, Osmar P.; Christou, Evangelos A.

2011-01-01

The purpose of this study was to compare force variability and the neural activation of the agonist muscle during constant isometric contractions at different force levels when the amplitude of respiration and visual feedback were varied. Twenty young adults (20–32 years, 10 men and 10 women) were instructed to accurately match a target force at 15 and 50% of their maximal voluntary contraction (MVC) with abduction of the index finger while controlling their respiration at different amplitudes (85, 100 and 125% normal) in the presence and absence of visual feedback. Each trial lasted 22 s and visual feedback was removed from 8–12 to 16–20 s. Each subject performed 3 trials with each respiratory condition at each force level. Force variability was quantified as the standard deviation of the detrended force data. The neural activation of the first dorsal interosseus (FDI) was measured with bipolar surface electrodes placed distal to the innervation zone. Relative to normal respiration, force variability increased significantly only during high-amplitude respiration (~63%). The increase in force variability from normal- to high-amplitude respiration was strongly associated with amplified force oscillations from 0–3 Hz (R2 ranged from .68 – .84; p < .001). Furthermore, the increase in force variability was exacerbated in the presence of visual feedback at 50% MVC (vision vs. no-vision: .97 vs. .87 N) and was strongly associated with amplified force oscillations from 0–1 Hz (R2 = .82) and weakly associated with greater power from 12–30 Hz (R2 = .24) in the EMG of the agonist muscle. Our findings demonstrate that high-amplitude respiration and visual feedback of force interact and amplify force variability in young adults during moderate levels of effort. PMID:21546109

Real-time feedback on nonverbal clinical communication. Theoretical framework and clinician acceptance of ambient visual design.

PubMed

Hartzler, A L; Patel, R A; Czerwinski, M; Pratt, W; Roseway, A; Chandrasekaran, N; Back, A

2014-01-01

This article is part of the focus theme of Methods of Information in Medicine on "Pervasive Intelligent Technologies for Health". Effective nonverbal communication between patients and clinicians fosters both the delivery of empathic patient-centered care and positive patient outcomes. Although nonverbal skill training is a recognized need, few efforts to enhance patient-clinician communication provide visual feedback on nonverbal aspects of the clinical encounter. We describe a novel approach that uses social signal processing technology (SSP) to capture nonverbal cues in real time and to display ambient visual feedback on control and affiliation--two primary, yet distinct dimensions of interpersonal nonverbal communication. To examine the design and clinician acceptance of ambient visual feedback on nonverbal communication, we 1) formulated a model of relational communication to ground SSP and 2) conducted a formative user study using mixed methods to explore the design of visual feedback. Based on a model of relational communication, we reviewed interpersonal communication research to map nonverbal cues to signals of affiliation and control evidenced in patient-clinician interaction. Corresponding with our formulation of this theoretical framework, we designed ambient real-time visualizations that reflect variations of affiliation and control. To explore clinicians' acceptance of this visual feedback, we conducted a lab study using the Wizard-of-Oz technique to simulate system use with 16 healthcare professionals. We followed up with seven of those participants through interviews to iterate on the design with a revised visualization that addressed emergent design considerations. Ambient visual feedback on non- verbal communication provides a theoretically grounded and acceptable way to provide clinicians with awareness of their nonverbal communication style. We provide implications for the design of such visual feedback that encourages empathic patient-centered communication and include considerations of metaphor, color, size, position, and timing of feedback. Ambient visual feedback from SSP holds promise as an acceptable means for facilitating empathic patient-centered nonverbal communication.

A cognitive neuroprosthetic that uses cortical stimulation for somatosensory feedback.

PubMed

Klaes, Christian; Shi, Ying; Kellis, Spencer; Minxha, Juri; Revechkis, Boris; Andersen, Richard A

2014-10-01

Present day cortical brain-machine interfaces (BMIs) have made impressive advances using decoded brain signals to control extracorporeal devices. Although BMIs are used in a closed-loop fashion, sensory feedback typically is visual only. However medical case studies have shown that the loss of somesthesis in a limb greatly reduces the agility of the limb even when visual feedback is available. To overcome this limitation, this study tested a closed-loop BMI that utilizes intracortical microstimulation to provide 'tactile' sensation to a non-human primate. Using stimulation electrodes in Brodmann area 1 of somatosensory cortex (BA1) and recording electrodes in the anterior intraparietal area, the parietal reach region and dorsal area 5 (area 5d), it was found that this form of feedback can be used in BMI tasks. Providing somatosensory feedback has the poyential to greatly improve the performance of cognitive neuroprostheses especially for fine control and object manipulation. Adding stimulation to a BMI system could therefore improve the quality of life for severely paralyzed patients.

Use of Visual and Proprioceptive Feedback to Improve Gait Speed and Spatiotemporal Symmetry Following Chronic Stroke: A Case Series

PubMed Central

Feasel, Jeff; Wentz, Erin; Brooks, Frederick P.; Whitton, Mary C.

2012-01-01

Background and Purpose Persistent deficits in gait speed and spatiotemporal symmetry are prevalent following stroke and can limit the achievement of community mobility goals. Rehabilitation can improve gait speed, but has shown limited ability to improve spatiotemporal symmetry. The incorporation of combined visual and proprioceptive feedback regarding spatiotemporal symmetry has the potential to be effective at improving gait. Case Description A 60-year-old man (18 months poststroke) and a 53-year-old woman (21 months poststroke) each participated in gait training to improve gait speed and spatiotemporal symmetry. Each patient performed 18 sessions (6 weeks) of combined treadmill-based gait training followed by overground practice. To assist with relearning spatiotemporal symmetry, treadmill-based training for both patients was augmented with continuous, real-time visual and proprioceptive feedback from an immersive virtual environment and a dual belt treadmill, respectively. Outcomes Both patients improved gait speed (patient 1: 0.35 m/s improvement; patient 2: 0.26 m/s improvement) and spatiotemporal symmetry. Patient 1, who trained with step-length symmetry feedback, improved his step-length symmetry ratio, but not his stance-time symmetry ratio. Patient 2, who trained with stance-time symmetry feedback, improved her stance-time symmetry ratio. She had no step-length asymmetry before training. Discussion Both patients made improvements in gait speed and spatiotemporal symmetry that exceeded those reported in the literature. Further work is needed to ascertain the role of combined visual and proprioceptive feedback for improving gait speed and spatiotemporal symmetry after chronic stroke. PMID:22228605

Stereoscopic visualization and haptic technology used to create a virtual environment for remote surgery - biomed 2011.

PubMed

Bornhoft, J M; Strabala, K W; Wortman, T D; Lehman, A C; Oleynikov, D; Farritor, S M

2011-01-01

The objective of this research is to study the effectiveness of using a stereoscopic visualization system for performing remote surgery. The use of stereoscopic vision has become common with the advent of the da Vinci® system (Intuitive, Sunnyvale CA). This system creates a virtual environment that consists of a 3-D display for visual feedback and haptic tactile feedback, together providing an intuitive environment for remote surgical applications. This study will use simple in vivo robotic surgical devices and compare the performance of surgeons using the stereoscopic interfacing system to the performance of surgeons using one dimensional monitors. The stereoscopic viewing system consists of two cameras, two monitors, and four mirrors. The cameras are mounted to a multi-functional miniature in vivo robot; and mimic the depth perception of the actual human eyes. This is done by placing the cameras at a calculated angle and distance apart. Live video streams from the left and right cameras are displayed on the left and right monitors, respectively. A system of angled mirrors allows the left and right eyes to see the video stream from the left and right monitor, respectively, creating the illusion of depth. The haptic interface consists of two PHANTOM Omni® (SensAble, Woburn Ma) controllers. These controllers measure the position and orientation of a pen-like end effector with three degrees of freedom. As the surgeon uses this interface, they see a 3-D image and feel force feedback for collision and workspace limits. The stereoscopic viewing system has been used in several surgical training tests and shows a potential improvement in depth perception and 3-D vision. The haptic system accurately gives force feedback that aids in surgery. Both have been used in non-survival animal surgeries, and have successfully been used in suturing and gallbladder removal. Bench top experiments using the interfacing system have also been conducted. A group of participants completed two different surgical training tasks using both a two dimensional visual system and the stereoscopic visual system. Results suggest that the stereoscopic visual system decreased the amount of time taken to complete the tasks. All participants also reported that the stereoscopic system was easier to utilize than the two dimensional system. Haptic controllers combined with stereoscopic vision provides for a more intuitive virtual environment. This system provides the surgeon with 3-D vision, depth perception, and the ability to receive feedback through forces applied in the haptic controller while performing surgery. These capabilities potentially enable the performance of more complex surgeries with a higher level of precision.

The Effects of Self-Generated Synchronous and Asynchronous Visual Speech Feedback on Overt Stuttering Frequency

ERIC Educational Resources Information Center

Snyder, Gregory J.; Hough, Monica Strauss; Blanchet, Paul; Ivy, Lennette J.; Waddell, Dwight

2009-01-01

Purpose: Relatively recent research documents that visual choral speech, which represents an externally generated form of synchronous visual speech feedback, significantly enhanced fluency in those who stutter. As a consequence, it was hypothesized that self-generated synchronous and asynchronous visual speech feedback would likewise enhance…

Role of Visual Feedback Treatment for Defective /s/ Sounds in Patients with Cleft Palate.

ERIC Educational Resources Information Center

Michi, Ken-ichi; And Others

1993-01-01

Six patients with cleft palate were provided treatment using either visual feedback for tongue placement and frication or no visual feedback. Results indicated the feedback was especially useful in the treatment of defective /s/ sounds in the patients who exhibited abnormal posterior tongue posturing during dental or alveolar sounds. (Author/DB)

Auditory short-term memory activation during score reading.

PubMed

Simoens, Veerle L; Tervaniemi, Mari

2013-01-01

Performing music on the basis of reading a score requires reading ahead of what is being played in order to anticipate the necessary actions to produce the notes. Score reading thus not only involves the decoding of a visual score and the comparison to the auditory feedback, but also short-term storage of the musical information due to the delay of the auditory feedback during reading ahead. This study investigates the mechanisms of encoding of musical information in short-term memory during such a complicated procedure. There were three parts in this study. First, professional musicians participated in an electroencephalographic (EEG) experiment to study the slow wave potentials during a time interval of short-term memory storage in a situation that requires cross-modal translation and short-term storage of visual material to be compared with delayed auditory material, as it is the case in music score reading. This delayed visual-to-auditory matching task was compared with delayed visual-visual and auditory-auditory matching tasks in terms of EEG topography and voltage amplitudes. Second, an additional behavioural experiment was performed to determine which type of distractor would be the most interfering with the score reading-like task. Third, the self-reported strategies of the participants were also analyzed. All three parts of this study point towards the same conclusion according to which during music score reading, the musician most likely first translates the visual score into an auditory cue, probably starting around 700 or 1300 ms, ready for storage and delayed comparison with the auditory feedback.

Auditory Short-Term Memory Activation during Score Reading

PubMed Central

Simoens, Veerle L.; Tervaniemi, Mari

2013-01-01

Performing music on the basis of reading a score requires reading ahead of what is being played in order to anticipate the necessary actions to produce the notes. Score reading thus not only involves the decoding of a visual score and the comparison to the auditory feedback, but also short-term storage of the musical information due to the delay of the auditory feedback during reading ahead. This study investigates the mechanisms of encoding of musical information in short-term memory during such a complicated procedure. There were three parts in this study. First, professional musicians participated in an electroencephalographic (EEG) experiment to study the slow wave potentials during a time interval of short-term memory storage in a situation that requires cross-modal translation and short-term storage of visual material to be compared with delayed auditory material, as it is the case in music score reading. This delayed visual-to-auditory matching task was compared with delayed visual-visual and auditory-auditory matching tasks in terms of EEG topography and voltage amplitudes. Second, an additional behavioural experiment was performed to determine which type of distractor would be the most interfering with the score reading-like task. Third, the self-reported strategies of the participants were also analyzed. All three parts of this study point towards the same conclusion according to which during music score reading, the musician most likely first translates the visual score into an auditory cue, probably starting around 700 or 1300 ms, ready for storage and delayed comparison with the auditory feedback. PMID:23326487

Design and test of a Microsoft Kinect-based system for delivering adaptive visual feedback to stroke patients during training of upper limb movement.

PubMed

Simonsen, Daniel; Popovic, Mirjana B; Spaich, Erika G; Andersen, Ole Kæseler

2017-11-01

The present paper describes the design and test of a low-cost Microsoft Kinect-based system for delivering adaptive visual feedback to stroke patients during the execution of an upper limb exercise. Eleven sub-acute stroke patients with varying degrees of upper limb function were recruited. Each subject participated in a control session (repeated twice) and a feedback session (repeated twice). In each session, the subjects were presented with a rectangular pattern displayed on a vertical mounted monitor embedded in the table in front of the patient. The subjects were asked to move a marker inside the rectangular pattern by using their most affected hand. During the feedback session, the thickness of the rectangular pattern was changed according to the performance of the subject, and the color of the marker changed according to its position, thereby guiding the subject's movements. In the control session, the thickness of the rectangular pattern and the color of the marker did not change. The results showed that the movement similarity and smoothness was higher in the feedback session than in the control session while the duration of the movement was longer. The present study showed that adaptive visual feedback delivered by use of the Kinect sensor can increase the similarity and smoothness of upper limb movement in stroke patients.

Combined mirror visual and auditory feedback therapy for upper limb phantom pain: a case report

PubMed Central

2011-01-01

Introduction Phantom limb sensation and phantom limb pain is a very common issue after amputations. In recent years there has been accumulating data implicating 'mirror visual feedback' or 'mirror therapy' as helpful in the treatment of phantom limb sensation and phantom limb pain. Case presentation We present the case of a 24-year-old Caucasian man, a left upper limb amputee, treated with mirror visual feedback combined with auditory feedback with improved pain relief. Conclusion This case may suggest that auditory feedback might enhance the effectiveness of mirror visual feedback and serve as a valuable addition to the complex multi-sensory processing of body perception in patients who are amputees. PMID:21272334

Developmental remodeling of corticocortical feedback circuits in ferret visual cortex

PubMed Central

Khalil, Reem; Levitt, Jonathan B.

2014-01-01

Visual cortical areas in the mammalian brain are linked through a system of interareal feedforward and feedback connections, which presumably underlie different visual functions. We characterized the refinement of feedback projections to primary visual cortex (V1) from multiple sources in juvenile ferrets ranging in age from four to ten weeks postnatal. We studied whether the refinement of different aspects of feedback circuitry from multiple visual cortical areas proceeds at a similar rate in all areas. We injected the neuronal tracer cholera toxin B (CTb) into V1, and mapped the areal and laminar distribution of retrogradely labeled cells in extrastriate cortex. Around the time of eye opening at four weeks postnatal, the retinotopic arrangement of feedback appears essentially adultlike; however, Suprasylvian cortex supplies the greatest proportion of feedback, whereas area 18 supplies the greatest proportion in the adult. The density of feedback cells and the ratio of supragranular/infragranular feedback contribution declined in this period at a similar rate in all cortical areas. We also find significant feedback to V1 from layer IV of all extrastriate areas. The regularity of cell spacing, the proportion of feedback arising from layer IV, and the tangential extent of feedback in each area all remained essentially unchanged during this period, except for the infragranular feedback source in area 18 which expanded. Thus, while much of the basic pattern of cortical feedback to V1 is present before eye opening, there is major synchronous reorganization after eye opening, suggesting a crucial role for visual experience in this remodeling process. PMID:24665018

Developmental remodeling of corticocortical feedback circuits in ferret visual cortex.

PubMed

Khalil, Reem; Levitt, Jonathan B

2014-10-01

Visual cortical areas in the mammalian brain are linked through a system of interareal feedforward and feedback connections, which presumably underlie different visual functions. We characterized the refinement of feedback projections to primary visual cortex (V1) from multiple sources in juvenile ferrets ranging in age from 4-10 weeks postnatal. We studied whether the refinement of different aspects of feedback circuitry from multiple visual cortical areas proceeds at a similar rate in all areas. We injected the neuronal tracer cholera toxin B (CTb) into V1 and mapped the areal and laminar distribution of retrogradely labeled cells in extrastriate cortex. Around the time of eye opening at 4 weeks postnatal, the retinotopic arrangement of feedback appears essentially adult-like; however, suprasylvian cortex supplies the greatest proportion of feedback, whereas area 18 supplies the greatest proportion in the adult. The density of feedback cells and the ratio of supragranular/infragranular feedback contribution declined in this period at a similar rate in all cortical areas. We also found significant feedback to V1 from layer IV of all extrastriate areas. The regularity of cell spacing, the proportion of feedback arising from layer IV, and the tangential extent of feedback in each area all remained essentially unchanged during this period, except for the infragranular feedback source in area 18, which expanded. Thus, while much of the basic pattern of cortical feedback to V1 is present before eye opening, there is major synchronous reorganization after eye opening, suggesting a crucial role for visual experience in this remodeling process. © 2014 Wiley Periodicals, Inc.

Influence of Vibrotactile Feedback on Controlling Tilt Motion After Spaceflight

NASA Technical Reports Server (NTRS)

Wood, S. J.; Rupert, A. H.; Vanya, R. D.; Esteves, J. T.; Clement, G.

2011-01-01

We hypothesize that adaptive changes in how inertial cues from the vestibular system are integrated with other sensory information leads to perceptual disturbances and impaired manual control following transitions between gravity environments. The primary goals of this ongoing post-flight investigation are to quantify decrements in manual control of tilt motion following short-duration spaceflight and to evaluate vibrotactile feedback of tilt as a sensorimotor countermeasure. METHODS. Data is currently being collected on 9 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s, <20 cm radius) in a darkened room is utilized to elicit otolith reflexes in the lateral plane without concordant canal or visual cues. A Tilt-Translation Sled (TTS) is capable of synchronizing pitch tilt with fore-aft translation to align the resultant gravitoinertial vector with the longitudinal body axis, thereby eliciting canal reflexes without concordant otolith or visual cues. A simple 4 tactor system was implemented to provide feedback when tilt position exceeded predetermined levels in either device. Closed-loop nulling tasks are performed during random tilt steps or sum-of-sines (TTS only) with and without vibrotactile feedback of chair position. RESULTS. On landing day the manual control performance without vibrotactile feedback was reduced by >30% based on the gain or the amount of tilt disturbance successfully nulled. Manual control performance tended to return to baseline levels within 1-2 days following landing. Root-mean-square position error and tilt velocity were significantly reduced with vibrotactile feedback. CONCLUSIONS. These preliminary results are consistent with our hypothesis that adaptive changes in vestibular processing corresponds to reduced manual control performance following G-transitions. A simple vibrotactile prosthesis improves the ability to null out tilt motion within a limited range of motion disturbances.

A systematic review: the influence of real time feedback on wheelchair propulsion biomechanics.

PubMed

Symonds, Andrew; Barbareschi, Giulia; Taylor, Stephen; Holloway, Catherine

2018-01-01

Clinical guidelines recommend that, in order to minimize upper limb injury risk, wheelchair users adopt a semi-circular pattern with a slow cadence and a large push arc. To examine whether real time feedback can be used to influence manual wheelchair propulsion biomechanics. Clinical trials and case series comparing the use of real time feedback against no feedback were included. A general review was performed and methodological quality assessed by two independent practitioners using the Downs and Black checklist. The review was completed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Six papers met the inclusion criteria. Selected studies involved 123 participants and analysed the effect of visual and, in one case, haptic feedback. Across the studies it was shown that participants were able to achieve significant changes in propulsion biomechanics, when provided with real time feedback. However, the effect of targeting a single propulsion variable might lead to unwanted alterations in other parameters. Methodological assessment identified weaknesses in external validity. Visual feedback could be used to consistently increase push arc and decrease push rate, and may be the best focus for feedback training. Further investigation is required to assess such intervention during outdoor propulsion. Implications for Rehabilitation Upper limb pain and injuries are common secondary disorders that negatively affect wheelchair users' physical activity and quality of life. Clinical guidelines suggest that manual wheelchair users should aim to propel with a semi-circular pattern with low a push rate and large push arc in the range in order to minimise upper limbs' loading. Real time visual and haptic feedback are effective tools for improving propulsion biomechanics in both complete novices and experienced manual wheelchair users.

Feature saliency and feedback information interactively impact visual category learning

PubMed Central

Hammer, Rubi; Sloutsky, Vladimir; Grill-Spector, Kalanit

2015-01-01

Visual category learning (VCL) involves detecting which features are most relevant for categorization. VCL relies on attentional learning, which enables effectively redirecting attention to object’s features most relevant for categorization, while ‘filtering out’ irrelevant features. When features relevant for categorization are not salient, VCL relies also on perceptual learning, which enables becoming more sensitive to subtle yet important differences between objects. Little is known about how attentional learning and perceptual learning interact when VCL relies on both processes at the same time. Here we tested this interaction. Participants performed VCL tasks in which they learned to categorize novel stimuli by detecting the feature dimension relevant for categorization. Tasks varied both in feature saliency (low-saliency tasks that required perceptual learning vs. high-saliency tasks), and in feedback information (tasks with mid-information, moderately ambiguous feedback that increased attentional load, vs. tasks with high-information non-ambiguous feedback). We found that mid-information and high-information feedback were similarly effective for VCL in high-saliency tasks. This suggests that an increased attentional load, associated with the processing of moderately ambiguous feedback, has little effect on VCL when features are salient. In low-saliency tasks, VCL relied on slower perceptual learning; but when the feedback was highly informative participants were able to ultimately attain the same performance as during the high-saliency VCL tasks. However, VCL was significantly compromised in the low-saliency mid-information feedback task. We suggest that such low-saliency mid-information learning scenarios are characterized by a ‘cognitive loop paradox’ where two interdependent learning processes have to take place simultaneously. PMID:25745404

The effects of spatially displaced visual feedback on remote manipulator performance

NASA Technical Reports Server (NTRS)

Smith, Randy L.; Stuart, Mark A.

1989-01-01

The effects of spatially displaced visual feedback on the operation of a camera viewed remote manipulation task are analyzed. A remote manipulation task is performed by operators exposed to the following different viewing conditions: direct view of the work site; normal camera view; reversed camera view; inverted/reversed camera view; and inverted camera view. The task completion performance times are statistically analyzed with a repeated measures analysis of variance, and a Newman-Keuls pairwise comparison test is administered to the data. The reversed camera view is ranked third out of four camera viewing conditions, while the normal viewing condition is found significantly slower than the direct viewing condition. It is shown that generalization to remote manipulation applications based upon the results of direct manipulation studies are quite useful, but they should be made cautiously.

Interaction between postural asymmetry and visual feedback effects in undisturbed upright stance control in healthy adults.

PubMed

Rougier, Patrice R; Boudrahem, Samir

2017-09-01

The technique of additional visual feedback has been shown to significantly decrease the center of pressure (CP) displacements of a standing subject. Body-weight asymmetry is known to increase postural instability due to difficulties in coordinating the reaction forces exerted under each foot and is often a cardinal feature of various neurological and traumatic diseases. To examine the possible interactions between additional visual feedback and body-weight asymmetry effects, healthy adults were recruited in a protocol with and without additional visual feedback, with different levels of body-weight asymmetry. CP displacements under each foot were recorded and used to compute the resultant CP displacements (CP Res ) and to estimate vertically projected center of gravity (CG v ) and CP Res -CG v displacements. Overall, six conditions were randomly proposed combining two factors: asymmetry with three BW percentage distributions (50/50, 35/65 and 20/80; left/right leg) and feedback (with or without additional VFB). The additional visual feedback technique principally reduces CG v displacements, whereas asymmetry increases CP Res -CG v displacements along the mediolateral axis. Some effects on plantar CP displacements were also observed, but only under the unloaded foot. Interestingly, no interaction between additional visual feedback and body-weight asymmetry was reported. These results suggest that the various postural effects that ensue from manipulating additional visual feedback parameters, shown previously in healthy subjects in various studies, could also apply independently of the level of asymmetry. Visual feedback effects could be observed in patients presenting weight-bearing asymmetries. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The role of visual and direct force feedback in robotics-assisted mitral valve annuloplasty.

PubMed

Currie, Maria E; Talasaz, Ali; Rayman, Reiza; Chu, Michael W A; Kiaii, Bob; Peters, Terry; Trejos, Ana Luisa; Patel, Rajni

2017-09-01

The objective of this work was to determine the effect of both direct force feedback and visual force feedback on the amount of force applied to mitral valve tissue during ex vivo robotics-assisted mitral valve annuloplasty. A force feedback-enabled master-slave surgical system was developed to provide both visual and direct force feedback during robotics-assisted cardiac surgery. This system measured the amount of force applied by novice and expert surgeons to cardiac tissue during ex vivo mitral valve annuloplasty repair. The addition of visual (2.16 ± 1.67), direct (1.62 ± 0.86), or both visual and direct force feedback (2.15 ± 1.08) resulted in lower mean maximum force applied to mitral valve tissue while suturing compared with no force feedback (3.34 ± 1.93 N; P < 0.05). To achieve better control of interaction forces on cardiac tissue during robotics-assisted mitral valve annuloplasty suturing, force feedback may be required. Copyright © 2016 John Wiley & Sons, Ltd.

Mirror Visual Feedback Training Improves Intermanual Transfer in a Sport-Specific Task: A Comparison between Different Skill Levels.

PubMed

Steinberg, Fabian; Pixa, Nils Henrik; Doppelmayr, Michael

2016-01-01

Mirror training therapy is a promising tool to initiate neural plasticity and facilitate the recovery process of motor skills after diseases such as stroke or hemiparesis by improving the intermanual transfer of fine motor skills in healthy people as well as in patients. This study evaluated whether these augmented performance improvements by mirror visual feedback (MVF) could be used for learning a sport-specific skill and if the effects are modulated by skill level. A sample of 39 young, healthy, and experienced basketball and handball players and 41 novices performed a stationary basketball dribble task at a mirror box in a standing position and received either MVF or direct feedback. After four training days using only the right hand, performance of both hands improved from pre- to posttest measurements. Only the left hand (untrained) performance of the experienced participants receiving MVF was more pronounced than for the control group. This indicates that intermanual motor transfer can be improved by MVF in a sport-specific task. However, this effect cannot be generalized to motor learning per se since it is modulated by individuals' skill level, a factor that might be considered in mirror therapy research.

Mirror Visual Feedback Training Improves Intermanual Transfer in a Sport-Specific Task: A Comparison between Different Skill Levels

PubMed Central

Pixa, Nils Henrik; Doppelmayr, Michael

2016-01-01

Mirror training therapy is a promising tool to initiate neural plasticity and facilitate the recovery process of motor skills after diseases such as stroke or hemiparesis by improving the intermanual transfer of fine motor skills in healthy people as well as in patients. This study evaluated whether these augmented performance improvements by mirror visual feedback (MVF) could be used for learning a sport-specific skill and if the effects are modulated by skill level. A sample of 39 young, healthy, and experienced basketball and handball players and 41 novices performed a stationary basketball dribble task at a mirror box in a standing position and received either MVF or direct feedback. After four training days using only the right hand, performance of both hands improved from pre- to posttest measurements. Only the left hand (untrained) performance of the experienced participants receiving MVF was more pronounced than for the control group. This indicates that intermanual motor transfer can be improved by MVF in a sport-specific task. However, this effect cannot be generalized to motor learning per se since it is modulated by individuals' skill level, a factor that might be considered in mirror therapy research. PMID:27642526

[Nursing Experience of Using Mirror Visual Feedback for a Schizophrenia Patient With Visual Hallucinations].

PubMed

Lan, Shu-Ling; Chen, Yu-Chi; Chang, Hsiu-Ju

2018-06-01

The aim of this paper was to describe the nursing application of mirror visual feedback in a patient suffering from long-term visual hallucinations. The intervention period was from May 15th to October 19th, 2015. Using the five facets of psychiatric nursing assessment, several health problems were observed, including disturbed sensory perceptions (prominent visual hallucinations) and poor self-care (e.g. limited abilities to self-bathe and put on clothing). Furthermore, "caregiver role strain" due to the related intense care burden was noted. After building up a therapeutic interpersonal relationship, the technique of brain plasticity and mirror visual feedback were performed using multiple nursing care methods in order to help the patient suppress her visual hallucinations by enhancing a different visual stimulus. We also taught her how to cope with visual hallucinations in a proper manner. The frequency and content of visual hallucinations were recorded to evaluate the effects of management. The therapeutic plan was formulated together with the patient in order to boost her self-confidence, and a behavior contract was implemented in order to improve her personal hygiene. In addition, psychoeducation on disease-related topics was provided to the patient's family, and they were encouraged to attend relevant therapeutic activities. As a result, her family became less passive and negative and more engaged in and positive about her future. The crisis of "caregiver role strain" was successfully resolved. The current experience is hoped to serve as a model for enhancing communication and cooperation between family and staff in similar medical settings.

Effects of Visual Force Feedback on Robot-Assisted Surgical Task Performance

PubMed Central

Reiley, Carol E.; Akinbiyi, Takintope; Burschka, Darius; Chang, David C.; Okamura, Allison M.; Yuh, David D.

2009-01-01

Background Direct haptic (force or tactile) feedback is negligible in current surgical robotic systems. The relevance of haptic feedback in robot-assisted performances of surgical tasks is controversial. We studied the effects of visual force feedback (VFF), a haptic feedback surrogate, on tying surgical knots with fine sutures similar to those used in cardiovascular surgery. Methods Using a modified da Vinci robotic system (Intuitive Surgical, Inc.) equipped with force-sensing instrument tips and real-time VFF overlays in the console image, ten surgeons each tied 10 knots with and 10 knots without VFF. Four surgeons had significant prior da Vinci experience while the remaining six surgeons did not. Performance parameters, including suture breakage and secure knots, peak and standard deviation of applied forces, and completion times using 5-0 silk sutures were recorded. Chi-square and Student’s t-test analyses determined differences between groups. Results Among surgeon subjects with robotic experience, no differences in measured performance parameters were found between robot-assisted knot ties executed with and without VFF. Among surgeons without robotic experience, however, VFF was associated with lower suture breakage rates, peak applied forces, and standard deviations of applied forces. VFF did not impart differences in knot completion times or loose knots for either surgeon group. Conclusions VFF resulted in reduced suture breakage, lower forces, and decreased force inconsistencies among novice robotic surgeons, although elapsed time and knot quality were unaffected. In contrast, VFF did not affect these metrics among experienced da Vinci surgeons. These results suggest that VFF primarily benefits novice robot-assisted surgeons, with diminishing benefits among experienced surgeons. PMID:18179942

Effects of visual feedback-induced variability on motor learning of handrim wheelchair propulsion.

PubMed

Leving, Marika T; Vegter, Riemer J K; Hartog, Johanneke; Lamoth, Claudine J C; de Groot, Sonja; van der Woude, Lucas H V

2015-01-01

It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process. 17 Participants received visual feedback-based practice (feedback group) and 15 participants received regular practice (natural learning group). Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block) and optimize it in the prescribed direction (2nd 4-min block). To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability. The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group. These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not always appear simultaneously during the motor learning process. Their relationship is most likely modified by other factors such as the amount of the intra-individual variability.

Effects of Visual Feedback-Induced Variability on Motor Learning of Handrim Wheelchair Propulsion

PubMed Central

Leving, Marika T.; Vegter, Riemer J. K.; Hartog, Johanneke; Lamoth, Claudine J. C.; de Groot, Sonja; van der Woude, Lucas H. V.

2015-01-01

Background It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process. Methods 17 Participants received visual feedback-based practice (feedback group) and 15 participants received regular practice (natural learning group). Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block) and optimize it in the prescribed direction (2nd 4-min block). To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability. Results The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group. Conclusion These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not always appear simultaneously during the motor learning process. Their relationship is most likely modified by other factors such as the amount of the intra-individual variability. PMID:25992626

Marks Should Not Be the Focus of Assessment -- But How Can Change Be Achieved?

ERIC Educational Resources Information Center

Thompson, Darrall G.

2016-01-01

This paper attempts to address the possibility of real change after a hundred years of exam-based assessments that produce a single mark or grade as feedback on students' progress and abilities. It uses visual feedback and analysis of graduate attribute assessment to foreground the diversity of aspects of a student's performance across subject…

Attainment and retention of force moderation following laparoscopic resection training with visual force feedback.

PubMed

Hernandez, Rafael; Onar-Thomas, Arzu; Travascio, Francesco; Asfour, Shihab

2017-11-01

Laparoscopic training with visual force feedback can lead to immediate improvements in force moderation. However, the long-term retention of this kind of learning and its potential decay are yet unclear. A laparoscopic resection task and force sensing apparatus were designed to assess the benefits of visual force feedback training. Twenty-two male university students with no previous experience in laparoscopy underwent relevant FLS proficiency training. Participants were randomly assigned to either a control or treatment group. Both groups trained on the task for 2 weeks as follows: initial baseline, sixteen training trials, and post-test immediately after. The treatment group had visual force feedback during training, whereas the control group did not. Participants then performed four weekly test trials to assess long-term retention of training. Outcomes recorded were maximum pulling and pushing forces, completion time, and rated task difficulty. Extreme maximum pulling force values were tapered throughout both the training and retention periods. Average maximum pushing forces were significantly lowered towards the end of training and during retention period. No significant decay of applied force learning was found during the 4-week retention period. Completion time and rated task difficulty were higher during training, but results indicate that the difference eventually fades during the retention period. Significant differences in aptitude across participants were found. Visual force feedback training improves on certain aspects of force moderation in a laparoscopic resection task. Results suggest that with enough training there is no significant decay of learning within the first month of the retention period. It is essential to account for differences in aptitude between individuals in this type of longitudinal research. This study shows how an inexpensive force measuring system can be used with an FLS Trainer System after some retrofitting. Surgical instructors can develop their own tasks and adjust force feedback levels accordingly.

Influence of Whole-Body Vibration Training Without Visual Feedback on Balance and Lower-Extremity Muscle Strength of the Elderly: A Randomized Controlled Trial.

PubMed

Tseng, Shiuan-Yu; Lai, Chung-Liang; Chang, Kai-Ling; Hsu, Pi-Shan; Lee, Meng-Chih; Wang, Chun-Hou

2016-02-01

The purpose of this study was to investigate the influence of whole-body vibration (WBV) training without visual feedback on balance and lower-extremity muscle strength in the elderly.Elderly subjects who did not exercise regularly participated in this study. Subjects were randomly divided into a WBV with eyes open group, a visual feedback-deprived plus WBV (VFDWBV) group, and a control group (0 Hz, eyes open). WBV training was provided over a 3-month period, 3 times per week for 5 min each session. Balance performance was measured with the limits of stability test, and muscle strength was measured with an isokinetic dynamometer.A total of 45 elderly subjects with an average age of 69.22  ±  3.97 years, divided into a WBV group (n = 14), a VFDWBV group (n = 17), and a control group (n = 14), completed the trial. Statistically significant differences were found in the balance performance of the 3 groups at different time points (time × group interaction: F = 13.213, P < 0.001), and the VFDWBV group had more improvement in balance than the WBV and control groups. The strength of the knee extensor and flexor muscles had time × group interactions: F = 29.604, P < 0.001 and F = 4.684, P = 0.015, respectively; the VFDWBV group had more improvement on lower-extremity muscle strength than the WBV and control groups. The 6-month follow-up showed that the rates of hospital visits for medical services due to falls were 0% in the WBV group (0/14), 0% in the VFDWBV group (0/17), and 28.57% in the control group (4/14).Results showed that WBV training at 20  Hz without visual feedback can significantly improve the balance performance and lower-extremity muscle strength of the elderly.

Brain-computer interface: changes in performance using virtual reality techniques.

PubMed

Ron-Angevin, Ricardo; Díaz-Estrella, Antonio

2009-01-09

The ability to control electroencephalographic (EEG) signals when different mental tasks are carried out would provide a method of communication for people with serious motor function problems. This system is known as a brain-computer interface (BCI). Due to the difficulty of controlling one's own EEG signals, a suitable training protocol is required to motivate subjects, as it is necessary to provide some type of visual feedback allowing subjects to see their progress. Conventional systems of feedback are based on simple visual presentations, such as a horizontal bar extension. However, virtual reality is a powerful tool with graphical possibilities to improve BCI-feedback presentation. The objective of the study is to explore the advantages of the use of feedback based on virtual reality techniques compared to conventional systems of feedback. Sixteen untrained subjects, divided into two groups, participated in the experiment. A group of subjects was trained using a BCI system, which uses conventional feedback (bar extension), and another group was trained using a BCI system, which submits subjects to a more familiar environment, such as controlling a car to avoid obstacles. The obtained results suggest that EEG behaviour can be modified via feedback presentation. Significant differences in classification error rates between both interfaces were obtained during the feedback period, confirming that an interface based on virtual reality techniques can improve the feedback control, specifically for untrained subjects.

Memory-guided force output is associated with self-reported ADHD symptoms in young adults.

PubMed

Neely, Kristina A; Chennavasin, Amanda P; Yoder, Arie; Williams, Genevieve K R; Loken, Eric; Huang-Pollock, Cynthia L

2016-11-01

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed mental health disorder in childhood and persists into adulthood in up to 65 % of cases. ADHD is associated with adverse outcomes such as the ability to gain and maintain employment and is associated with an increased risk for substance abuse obesity workplace injuries and traffic accidents A majority of diagnosed children have motor deficits; however, few studies have examined motor deficits in young adults. This study provides a novel examination of visuomotor control of grip force in young adults with and without ADHD. Participants were instructed to maintain force production over a 20-second trial with and without real-time visual feedback about their performance. The results demonstrated that when visual feedback was available, adults with ADHD produced slightly higher grip force than controls. However, when visual feedback was removed, adults with ADHD had a faster rate of decay of force, which was associated with ADHD symptom severity and trait impulsivity. These findings suggest that there may be important differences in the way that adults with ADHD integrate visual feedback during continuous motor tasks. These may account for some of the motor impairments reported in children with ADHD. These deficits could result from (1) dysfunctional sensory motor integration and/or (2) deficits in short-term visuomotor memory.

Simultaneous tDCS-fMRI Identifies Resting State Networks Correlated with Visual Search Enhancement.

PubMed

Callan, Daniel E; Falcone, Brian; Wada, Atsushi; Parasuraman, Raja

2016-01-01

This study uses simultaneous transcranial direct current stimulation (tDCS) and functional MRI (fMRI) to investigate tDCS modulation of resting state activity and connectivity that underlies enhancement in behavioral performance. The experiment consisted of three sessions within the fMRI scanner in which participants conducted a visual search task: Session 1: Pre-training (no performance feedback), Session 2: Training (performance feedback given), Session 3: Post-training (no performance feedback). Resting state activity was recorded during the last 5 min of each session. During the 2nd session one group of participants underwent 1 mA tDCS stimulation and another underwent sham stimulation over the right posterior parietal cortex. Resting state spontaneous activity, as measured by fractional amplitude of low frequency fluctuations (fALFF), for session 2 showed significant differences between the tDCS stim and sham groups in the precuneus. Resting state functional connectivity from the precuneus to the substantia nigra, a subcortical dopaminergic region, was found to correlate with future improvement in visual search task performance for the stim over the sham group during active stimulation in session 2. The after-effect of stimulation on resting state functional connectivity was measured following a post-training experimental session (session 3). The left cerebellum Lobule VIIa Crus I showed performance related enhancement in resting state functional connectivity for the tDCS stim over the sham group. The ability to determine the relationship that the relative strength of resting state functional connectivity for an individual undergoing tDCS has on future enhancement in behavioral performance has wide ranging implications for neuroergonomic as well as therapeutic, and rehabilitative applications.

Visualization and analysis of flow structures in an open cavity

NASA Astrophysics Data System (ADS)

Liu, Jun; Cai, Jinsheng; Yang, Dangguo; Wu, Junqiang; Wang, Xiansheng

2018-05-01

A numerical study is performed on the supersonic flow over an open cavity at Mach number of 1.5. A newly developed visualization method is employed to visualize the complicated flow structures, which provide an insight into major flow physics. Four types of shock/compressive waves which existed in experimental schlieren are observed in numerical visualization results. Furthermore, other flow structures such as multi-scale vortices are also obtained in the numerical results. And a new type of shocklet which is beneath large vortices is found. The shocklet beneath the vortex originates from leading edge, then, is strengthened by successive interactions between feedback compressive waves and its attached vortex. Finally, it collides against the trailing surface and generates a large number of feedback compressive waves and intensive pressure fluctuations. It is suggested that the shocklets beneath vortex play an important role of cavity self-sustained oscillation.

Adaptation of handwriting size under distorted visual feedback in patients with Parkinson's disease and elderly and young controls

PubMed Central

Teulings, H; Contreras-Vidal, J; Stelmach, G; Adler, C

2002-01-01

Objective: The ability to use visual feedback to control handwriting size was compared in patients with Parkinson's disease (PD), elderly people, and young adults to better understand factors playing a part in parkinsonian micrographia. Methods: The participants wrote sequences of eight cursive l loops with visual target sizes of 0.5 and 2 cm on a flat panel display digitiser which both recorded and displayed the pen movements. In the pre-exposure and postexposure conditions, the display digitiser showed the actual pen trace in real time and real size. In the distortion exposure conditions, the gain of the vertical dimension of the visual feedback was either reduced to 70% or enlarged to 140%. Results: The young controls showed a gradual visuomotor adaptation that compensated for the visual feedback distortions during the exposure conditions. They also showed significant after effects during the postexposure conditions. The elderly controls marginally corrected for the size distortions and showed small after effects. The patients with PD, however, showed no trial by trial adaptations or after effects but instead, a progressive amplification of the distortion effect in each individual trial. Conclusion: The young controls used visual feedback to update their visuomotor map. The elderly controls seemed to make little use of visual feedback. The patients with Parkinson's disease rely on the visual feedback of previous or of ongoing strokes to programme subsequent strokes. This recursive feedback may play a part in the progressive reductions in handwriting size found in parkinsonian micrographia. PMID:11861687

Error amplification to promote motor learning and motivation in therapy robotics.

PubMed

Shirzad, Navid; Van der Loos, H F Machiel

2012-01-01

To study the effects of different feedback error amplification methods on a subject's upper-limb motor learning and affect during a point-to-point reaching exercise, we developed a real-time controller for a robotic manipulandum. The reaching environment was visually distorted by implementing a thirty degrees rotation between the coordinate systems of the robot's end-effector and the visual display. Feedback error amplification was provided to subjects as they trained to learn reaching within the visually rotated environment. Error amplification was provided either visually or through both haptic and visual means, each method with two different amplification gains. Subjects' performance (i.e., trajectory error) and self-reports to a questionnaire were used to study the speed and amount of adaptation promoted by each error amplification method and subjects' emotional changes. We found that providing haptic and visual feedback promotes faster adaptation to the distortion and increases subjects' satisfaction with the task, leading to a higher level of attentiveness during the exercise. This finding can be used to design a novel exercise regimen, where alternating between error amplification methods is used to both increase a subject's motor learning and maintain a minimum level of motivational engagement in the exercise. In future experiments, we will test whether such exercise methods will lead to a faster learning time and greater motivation to pursue a therapy exercise regimen.

A Randomized Control Trial of Cardiopulmonary Feedback Devices and Their Impact on Infant Chest Compression Quality: A Simulation Study.

PubMed

Austin, Andrea L; Spalding, Carmen N; Landa, Katrina N; Myer, Brian R; Donald, Cure; Smith, Jason E; Platt, Gerald; King, Heather C

2017-10-27

In effort to improve chest compression quality among health care providers, numerous feedback devices have been developed. Few studies, however, have focused on the use of cardiopulmonary resuscitation feedback devices for infants and children. This study evaluated the quality of chest compressions with standard team-leader coaching, a metronome (MetroTimer by ONYX Apps), and visual feedback (SkillGuide Cardiopulmonary Feedback Device) during simulated infant cardiopulmonary resuscitation. Seventy voluntary health care providers who had recently completed Pediatric Advanced Life Support or Basic Life Support courses were randomized to perform simulated infant cardiopulmonary resuscitation into 1 of 3 groups: team-leader coaching alone (control), coaching plus metronome, or coaching plus SkillGuide for 2 minutes continuously. Rate, depth, and frequency of complete recoil during cardiopulmonary resuscitation were recorded by the Laerdal SimPad device for each participant. American Heart Association-approved compression techniques were randomized to either 2-finger or encircling thumbs. The metronome was associated with more ideal compression rate than visual feedback or coaching alone (104/min vs 112/min and 113/min; P = 0.003, 0.019). Visual feedback was associated with more ideal depth than auditory (41 mm vs 38.9; P = 0.03). There were no significant differences in complete recoil between groups. Secondary outcomes of compression technique revealed a difference of 1 mm. Subgroup analysis of male versus female showed no difference in mean number of compressions (221.76 vs 219.79; P = 0.72), mean compression depth (40.47 vs 39.25; P = 0.09), or rate of complete release (70.27% vs 64.96%; P = 0.54). In the adult literature, feedback devices often show an increase in quality of chest compressions. Although more studies are needed, this study did not demonstrate a clinically significant improvement in chest compressions with the addition of a metronome or visual feedback device, no clinically significant difference in Pediatric Advanced Life Support-approved compression technique, and no difference between compression quality between genders.

Effect of acute augmented feedback on between limb asymmetries and eccentric knee flexor strength during the Nordic hamstring exercise.

PubMed

Chalker, Wade J; Shield, Anthony J; Opar, David A; Rathbone, Evelyne N; Keogh, Justin W L

2018-01-01

Hamstring strain injuries (HSI) are one of the most prevalent and serious injuries affecting athletes, particularly those in team ball sports or track and field. Recent evidence demonstrates that eccentric knee flexor weakness and between limb asymmetries are possible risk factors for HSIs. While eccentric hamstring resistance training, e.g. the Nordic hamstring exercise (NHE) significantly increases eccentric hamstring strength and reduces HSI risk, little research has examined whether between limb asymmetries can be reduced with training. As augmented feedback (AF) can produce significant acute and chronic increases in muscular strength and reduce injury risk, one way to address the limitation in the eccentric hamstring training literature may be to provide athletes real-time visual AF of their NHE force outputs with the goal to minimise the between limb asymmetry. Using a cross over study design, 44 injury free, male cricket players from two skill levels performed two NHE sessions on a testing device. The two NHE sessions were identical with the exception of AF, with the two groups randomised to perform the sessions with and without visual feedback of each limb's force production in real-time. When performing the NHE with visual AF, the participants were provided with the following instructions to 'reduce limb asymmetries as much as possible using the real-time visual force outputs displayed in front them'. Between limb asymmetries and mean peak force outputs were compared between the two feedback conditions (FB1 and FB2) using independent t -tests to ensure there was no carryover effect, and to determine any period and treatment effects. The magnitude of the differences in the force outputs were also examined using Cohen d effect size. There was a significant increase in mean peak force production when feedback was provided (mean difference, 21.7 N; 95% CI [0.2-42.3 N]; P = 0.048; d = 0.61) and no significant difference in between limb asymmetry for feedback or no feedback (mean difference, 5.7%; 95% CI [-2.8% to 14.3%]; P = 0.184; d = 0.41). Increases in force production under feedback were a result of increased weak limb (mean difference, 15.0 N; 95% CI [1.6-28.5 N]; P = 0.029; d = 0.22) force contribution compared to the strong limb. The results of this study further support the potential utility of AF in improving force production and reducing risk in athletic populations. While there are currently some financial limitations to the application of this training approach, even in high-performance sport, such an approach may improve outcomes for HSI prevention programs. Further research with more homogenous populations over greater periods of time that assess the chronic effect of such training practices on injury risk factors and injury rates are also recommended.

Effect of Animated Graphic Annotations and Immediate Visual Feedback in Aiding Japanese Pronunciation Learning: A Comparative Study

ERIC Educational Resources Information Center

Hew, Soon-Hin; Ohki, Mitsuru

2004-01-01

This study examines the effectiveness of imagery and electronic visual feedback in facilitating students' acquisition of Japanese pronunciation skills. The independent variables, animated graphic annotation (AGA) and immediate visual feedback (IVF) were integrated into a Japanese computer-assisted language learning (JCALL) program focused on the…

The effects of spatially displaced visual feedback on remote manipulator performance

NASA Technical Reports Server (NTRS)

Smith, Randy L.; Stuart, Mark A.

1993-01-01

The results of this evaluation have important implications for the arrangement of remote manipulation worksites and the design of workstations for telerobot operations. This study clearly illustrates the deleterious effects that can accompany the performance of remote manipulator tasks when viewing conditions are less than optimal. Future evaluations should emphasize telerobot camera locations and the use of image/graphical enhancement techniques in an attempt to lessen the adverse effects of displaced visual feedback. An important finding in this evaluation is the extent to which results from previously performed direct manipulation studies can be generalized to remote manipulation studies. Even though the results obtained were very similar to those of the direct manipulation evaluations, there were differences as well. This evaluation has demonstrated that generalizations to remote manipulation applications based upon the results of direct manipulation studies are quite useful, but they should be made cautiously.

A computational investigation of feedforward and feedback processing in metacontrast backward masking

PubMed Central

Silverstein, David N.

2015-01-01

In human perception studies, visual backward masking has been used to understand the temporal dynamics of subliminal vs. conscious perception. When a brief target stimulus is followed by a masking stimulus after a short interval of <100 ms, performance on the target is impaired when the target and mask are in close spatial proximity. While the psychophysical properties of backward masking have been studied extensively, there is still debate on the underlying cortical dynamics. One prevailing theory suggests that the impairment of target performance due to the mask is the result of lateral inhibition between the target and mask in feedforward processing. Another prevailing theory suggests that this impairment is due to the interruption of feedback processing of the target by the mask. This computational study demonstrates that both aspects of these theories may be correct. Using a biophysical model of V1 and V2, visual processing was modeled as interacting neocortical attractors, which must propagate up the visual stream. If an activating target attractor in V1 is quiesced enough with lateral inhibition from a mask, or not reinforced by recurrent feedback, it is more likely to burn out before becoming fully active and progressing through V2 and beyond. Results are presented which simulate metacontrast backward masking with an increasing stimulus interval and with the presence and absence of feedback activity. This showed that recurrent feedback diminishes backward masking effects and can make conscious perception more likely. One model configuration presented a metacontrast noise mask in the same hypercolumns as the target, and produced type-A masking. A second model configuration presented a target line with two parallel adjacent masking lines, and produced type-B masking. Future work should examine how the model extends to more complex spatial mask configurations. PMID:25759672

Evaluation of Pseudo-Haptic Interactions with Soft Objects in Virtual Environments.

PubMed

Li, Min; Sareh, Sina; Xu, Guanghua; Ridzuan, Maisarah Binti; Luo, Shan; Xie, Jun; Wurdemann, Helge; Althoefer, Kaspar

2016-01-01

This paper proposes a pseudo-haptic feedback method conveying simulated soft surface stiffness information through a visual interface. The method exploits a combination of two feedback techniques, namely visual feedback of soft surface deformation and control of the indenter avatar speed, to convey stiffness information of a simulated surface of a soft object in virtual environments. The proposed method was effective in distinguishing different sizes of virtual hard nodules integrated into the simulated soft bodies. To further improve the interactive experience, the approach was extended creating a multi-point pseudo-haptic feedback system. A comparison with regards to (a) nodule detection sensitivity and (b) elapsed time as performance indicators in hard nodule detection experiments to a tablet computer incorporating vibration feedback was conducted. The multi-point pseudo-haptic interaction is shown to be more time-efficient than the single-point pseudo-haptic interaction. It is noted that multi-point pseudo-haptic feedback performs similarly well when compared to a vibration-based feedback method based on both performance measures elapsed time and nodule detection sensitivity. This proves that the proposed method can be used to convey detailed haptic information for virtual environmental tasks, even subtle ones, using either a computer mouse or a pressure sensitive device as an input device. This pseudo-haptic feedback method provides an opportunity for low-cost simulation of objects with soft surfaces and hard inclusions, as, for example, occurring in ever more realistic video games with increasing emphasis on interaction with the physical environment and minimally invasive surgery in the form of soft tissue organs with embedded cancer nodules. Hence, the method can be used in many low-budget applications where haptic sensation is required, such as surgeon training or video games, either using desktop computers or portable devices, showing reasonably high fidelity in conveying stiffness perception to the user.

Automatic medical image annotation and keyword-based image retrieval using relevance feedback.

PubMed

Ko, Byoung Chul; Lee, JiHyeon; Nam, Jae-Yeal

2012-08-01

This paper presents novel multiple keywords annotation for medical images, keyword-based medical image retrieval, and relevance feedback method for image retrieval for enhancing image retrieval performance. For semantic keyword annotation, this study proposes a novel medical image classification method combining local wavelet-based center symmetric-local binary patterns with random forests. For keyword-based image retrieval, our retrieval system use the confidence score that is assigned to each annotated keyword by combining probabilities of random forests with predefined body relation graph. To overcome the limitation of keyword-based image retrieval, we combine our image retrieval system with relevance feedback mechanism based on visual feature and pattern classifier. Compared with other annotation and relevance feedback algorithms, the proposed method shows both improved annotation performance and accurate retrieval results.

Visualizing Motion Patterns in Acupuncture Manipulation.

PubMed

Lee, Ye-Seul; Jung, Won-Mo; Lee, In-Seon; Lee, Hyangsook; Park, Hi-Joon; Chae, Younbyoung

2016-07-16

Acupuncture manipulation varies widely among practitioners in clinical settings, and it is difficult to teach novice students how to perform acupuncture manipulation techniques skillfully. The Acupuncture Manipulation Education System (AMES) is an open source software system designed to enhance acupuncture manipulation skills using visual feedback. Using a phantom acupoint and motion sensor, our method for acupuncture manipulation training provides visual feedback regarding the actual movement of the student's acupuncture manipulation in addition to the optimal or intended movement, regardless of whether the manipulation skill is lifting, thrusting, or rotating. Our results show that students could enhance their manipulation skills by training using this method. This video shows the process of manufacturing phantom acupoints and discusses several issues that may require the attention of individuals interested in creating phantom acupoints or operating this system.

Virtual reality training and assessment in laparoscopic rectum surgery.

PubMed

Pan, Jun J; Chang, Jian; Yang, Xiaosong; Liang, Hui; Zhang, Jian J; Qureshi, Tahseen; Howell, Robert; Hickish, Tamas

2015-06-01

Virtual-reality (VR) based simulation techniques offer an efficient and low cost alternative to conventional surgery training. This article describes a VR training and assessment system in laparoscopic rectum surgery. To give a realistic visual performance of interaction between membrane tissue and surgery tools, a generalized cylinder based collision detection and a multi-layer mass-spring model are presented. A dynamic assessment model is also designed for hierarchy training evaluation. With this simulator, trainees can operate on the virtual rectum with both visual and haptic sensation feedback simultaneously. The system also offers surgeons instructions in real time when improper manipulation happens. The simulator has been tested and evaluated by ten subjects. This prototype system has been verified by colorectal surgeons through a pilot study. They believe the visual performance and the tactile feedback are realistic. It exhibits the potential to effectively improve the surgical skills of trainee surgeons and significantly shorten their learning curve. Copyright © 2014 John Wiley & Sons, Ltd.

Sonification and haptic feedback in addition to visual feedback enhances complex motor task learning.

PubMed

Sigrist, Roland; Rauter, Georg; Marchal-Crespo, Laura; Riener, Robert; Wolf, Peter

2015-03-01

Concurrent augmented feedback has been shown to be less effective for learning simple motor tasks than for complex tasks. However, as mostly artificial tasks have been investigated, transfer of results to tasks in sports and rehabilitation remains unknown. Therefore, in this study, the effect of different concurrent feedback was evaluated in trunk-arm rowing. It was then investigated whether multimodal audiovisual and visuohaptic feedback are more effective for learning than visual feedback only. Naïve subjects (N = 24) trained in three groups on a highly realistic virtual reality-based rowing simulator. In the visual feedback group, the subject's oar was superimposed to the target oar, which continuously became more transparent when the deviation between the oars decreased. Moreover, a trace of the subject's trajectory emerged if deviations exceeded a threshold. The audiovisual feedback group trained with oar movement sonification in addition to visual feedback to facilitate learning of the velocity profile. In the visuohaptic group, the oar movement was inhibited by path deviation-dependent braking forces to enhance learning of spatial aspects. All groups significantly decreased the spatial error (tendency in visual group) and velocity error from baseline to the retention tests. Audiovisual feedback fostered learning of the velocity profile significantly more than visuohaptic feedback. The study revealed that well-designed concurrent feedback fosters complex task learning, especially if the advantages of different modalities are exploited. Further studies should analyze the impact of within-feedback design parameters and the transferability of the results to other tasks in sports and rehabilitation.

Examining action effects in the execution of a skilled soccer kick by using erroneous feedback.

PubMed

Ford, Paul; Hodges, Nicola J; Williams, A Mark

2007-11-01

The authors examined the role of action effects (i.e., ball trajectory) during the performance of a soccer kick. Participants were 20 expert players who kicked a ball over a height barrier toward a ground-level target. The authors occluded participants' vision of the ball trajectory after foot-to-ball contact. Participants in a 1st group received erroneous feedback from a video that showed a ball-trajectory apex approximately 75 cm lower than that of their actual kick, although the ball's landing position was unaltered. Participants in a 2nd group received correct video feedback of both the ball trajectory and the landing position. The erroneous-feedback group showed a significant bias toward higher ball trajectories than did the correct-feedback group. The authors conclude that performers at high levels of skill use the visual consequences of the action to plan and execute an action.

An Investigation into the Cognition Behind Spontaneous String Pulling in New Caledonian Crows

PubMed Central

Taylor, Alex H.; Medina, Felipe S.; Holzhaider, Jennifer C.; Hearne, Lindsay J.; Hunt, Gavin R.; Gray, Russell D.

2010-01-01

The ability of some bird species to pull up meat hung on a string is a famous example of spontaneous animal problem solving. The “insight” hypothesis claims that this complex behaviour is based on cognitive abilities such as mental scenario building and imagination. An operant conditioning account, in contrast, would claim that this spontaneity is due to each action in string pulling being reinforced by the meat moving closer and remaining closer to the bird on the perch. We presented experienced and naïve New Caledonian crows with a novel, visually restricted string-pulling problem that reduced the quality of visual feedback during string pulling. Experienced crows solved this problem with reduced efficiency and increased errors compared to their performance in standard string pulling. Naïve crows either failed or solved the problem by trial and error learning. However, when visual feedback was available via a mirror mounted next to the apparatus, two naïve crows were able to perform at the same level as the experienced group. Our results raise the possibility that spontaneous string pulling in New Caledonian crows may not be based on insight but on operant conditioning mediated by a perceptual-motor feedback cycle. PMID:20179759

A software module for implementing auditory and visual feedback on a video-based eye tracking system

NASA Astrophysics Data System (ADS)

Rosanlall, Bharat; Gertner, Izidor; Geri, George A.; Arrington, Karl F.

2016-05-01

We describe here the design and implementation of a software module that provides both auditory and visual feedback of the eye position measured by a commercially available eye tracking system. The present audio-visual feedback module (AVFM) serves as an extension to the Arrington Research ViewPoint EyeTracker, but it can be easily modified for use with other similar systems. Two modes of audio feedback and one mode of visual feedback are provided in reference to a circular area-of-interest (AOI). Auditory feedback can be either a click tone emitted when the user's gaze point enters or leaves the AOI, or a sinusoidal waveform with frequency inversely proportional to the distance from the gaze point to the center of the AOI. Visual feedback is in the form of a small circular light patch that is presented whenever the gaze-point is within the AOI. The AVFM processes data that are sent to a dynamic-link library by the EyeTracker. The AVFM's multithreaded implementation also allows real-time data collection (1 kHz sampling rate) and graphics processing that allow display of the current/past gaze-points as well as the AOI. The feedback provided by the AVFM described here has applications in military target acquisition and personnel training, as well as in visual experimentation, clinical research, marketing research, and sports training.

A new visual feedback-based magnetorheological haptic master for robot-assisted minimally invasive surgery

NASA Astrophysics Data System (ADS)

Choi, Seung-Hyun; Kim, Soomin; Kim, Pyunghwa; Park, Jinhyuk; Choi, Seung-Bok

2015-06-01

In this study, we developed a novel four-degrees-of-freedom haptic master using controllable magnetorheological (MR) fluid. We also integrated the haptic master with a vision device with image processing for robot-assisted minimally invasive surgery (RMIS). The proposed master can be used in RMIS as a haptic interface to provide the surgeon with a sense of touch by using both kinetic and kinesthetic information. The slave robot, which is manipulated with a proportional-integrative-derivative controller, uses a force sensor to obtain the desired forces from tissue contact, and these desired repulsive forces are then embodied through the MR haptic master. To verify the effectiveness of the haptic master, the desired force and actual force are compared in the time domain. In addition, a visual feedback system is implemented in the RMIS experiment to distinguish between the tumor and organ more clearly and provide better visibility to the operator. The hue-saturation-value color space is adopted for the image processing since it is often more intuitive than other color spaces. The image processing and haptic feedback are realized on surgery performance. In this work, tumor-cutting experiments are conducted under four different operating conditions: haptic feedback on, haptic feedback off, image processing on, and image processing off. The experimental realization shows that the performance index, which is a function of pixels, is different in the four operating conditions.

Effects of Real-Time Visual Feedback on Pre-Service Teachers' Singing

ERIC Educational Resources Information Center

Leong, S.; Cheng, L.

2014-01-01

This pilot study focuses on the use real-time visual feedback technology (VFT) in vocal training. The empirical research has two aims: to ascertain the effectiveness of the real-time visual feedback software "Sing & See" in the vocal training of pre-service music teachers and the teachers' perspective on their experience with…

Surgical evaluation of a novel tethered robotic capsule endoscope using micro-patterned treads.

PubMed

Sliker, Levin J; Kern, Madalyn D; Schoen, Jonathan A; Rentschler, Mark E

2012-10-01

The state-of-the-art technology for gastrointestinal (GI) tract exploration is a capsule endoscope (CE). Capsule endoscopes are pill-sized devices that provide visual feedback of the GI tract as they move passively through the patient. These passive devices could benefit from a mobility system enabling maneuverability and controllability. Potential benefits of a tethered robotic capsule endoscope (tRCE) include faster travel speeds, reaction force generation for biopsy, and decreased capsule retention. In this work, a tethered CE is developed with an active locomotion system for mobility within a collapsed lumen. Micro-patterned polydimethylsiloxane (PDMS) treads are implemented onto a custom capsule housing as a mobility method. The tRCE housing contains a direct current (DC) motor and gear train to drive the treads, a video camera for visual feedback, and two light sources (infrared and visible) for illumination. The device was placed within the insufflated abdomen of a live anesthetized pig to evaluate mobility performance on a planar tissue surface, as well as within the cecum to evaluate mobility performance in a collapsed lumen. The tRCE was capable of forward and reverse mobility for both planar and collapsed lumen tissue environments. Also, using an onboard visual system, the tRCE was capable of demonstrating visual feedback within an insufflated, anesthetized porcine abdomen. Proof-of-concept in vivo tRCE mobility using micro-patterned PDMS treads was shown. This suggests that a similar method could be implemented in future smaller, faster, and untethered RCEs.

Augmented reality and haptic interfaces for robot-assisted surgery.

PubMed

Yamamoto, Tomonori; Abolhassani, Niki; Jung, Sung; Okamura, Allison M; Judkins, Timothy N

2012-03-01

Current teleoperated robot-assisted minimally invasive surgical systems do not take full advantage of the potential performance enhancements offered by various forms of haptic feedback to the surgeon. Direct and graphical haptic feedback systems can be integrated with vision and robot control systems in order to provide haptic feedback to improve safety and tissue mechanical property identification. An interoperable interface for teleoperated robot-assisted minimally invasive surgery was developed to provide haptic feedback and augmented visual feedback using three-dimensional (3D) graphical overlays. The software framework consists of control and command software, robot plug-ins, image processing plug-ins and 3D surface reconstructions. The feasibility of the interface was demonstrated in two tasks performed with artificial tissue: palpation to detect hard lumps and surface tracing, using vision-based forbidden-region virtual fixtures to prevent the patient-side manipulator from entering unwanted regions of the workspace. The interoperable interface enables fast development and successful implementation of effective haptic feedback methods in teleoperation. Copyright © 2011 John Wiley & Sons, Ltd.

Use of visual CO2 feedback as a retrofit solution for improving classroom air quality.

PubMed

Wargocki, P; Da Silva, N A F

2015-02-01

Carbon dioxide (CO2 ) sensors that provide a visual indication were installed in classrooms during normal school operation. During 2-week periods, teachers and students were instructed to open the windows in response to the visual CO2 feedback in 1 week and open them, as they would normally do, without visual feedback, in the other week. In the heating season, two pairs of classrooms were monitored, one pair naturally and the other pair mechanically ventilated. In the cooling season, two pairs of naturally ventilated classrooms were monitored, one pair with split cooling in operation and the other pair with no cooling. Classrooms were matched by grade. Providing visual CO2 feedback reduced CO2 levels, as more windows were opened in this condition. This increased energy use for heating and reduced the cooling requirement in summertime. Split cooling reduced the frequency of window opening only when no visual CO2 feedback was present. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Haptic force-feedback devices for the office computer: performance and musculoskeletal loading issues.

PubMed

Dennerlein, J T; Yang, M C

2001-01-01

Pointing devices, essential input tools for the graphical user interface (GUI) of desktop computers, require precise motor control and dexterity to use. Haptic force-feedback devices provide the human operator with tactile cues, adding the sense of touch to existing visual and auditory interfaces. However, the performance enhancements, comfort, and possible musculoskeletal loading of using a force-feedback device in an office environment are unknown. Hypothesizing that the time to perform a task and the self-reported pain and discomfort of the task improve with the addition of force feedback, 26 people ranging in age from 22 to 44 years performed a point-and-click task 540 times with and without an attractive force field surrounding the desired target. The point-and-click movements were approximately 25% faster with the addition of force feedback (paired t-tests, p < 0.001). Perceived user discomfort and pain, as measured through a questionnaire, were also smaller with the addition of force feedback (p < 0.001). However, this difference decreased as additional distracting force fields were added to the task environment, simulating a more realistic work situation. These results suggest that for a given task, use of a force-feedback device improves performance, and potentially reduces musculoskeletal loading during mouse use. Actual or potential applications of this research include human-computer interface design, specifically that of the pointing device extensively used for the graphical user interface.

Effects of Varied Enhancement Strategies (Chunking, Feedback, Gaming) in Complementing Animated Instruction in Facilitating Different Types of Learning Objectives

ERIC Educational Resources Information Center

Munyofu, Mine

2008-01-01

The purpose of this study was to examine the instructional effectiveness of different levels of chunking (simple visual/text and complex visual/text), different forms of feedback (item-by-item feedback, end-of-test feedback and no feedback), and use of instructional gaming (game and no game) in complementing animated programmed instruction on a…

Variations in Static Force Control and Motor Unit Behavior with Error Amplification Feedback in the Elderly.

PubMed

Chen, Yi-Ching; Lin, Linda L; Lin, Yen-Ting; Hu, Chia-Ling; Hwang, Ing-Shiou

2017-01-01

Error amplification (EA) feedback is a promising approach to advance visuomotor skill. As error detection and visuomotor processing at short time scales decline with age, this study examined whether older adults could benefit from EA feedback that included higher-frequency information to guide a force-tracking task. Fourteen young and 14 older adults performed low-level static isometric force-tracking with visual guidance of typical visual feedback and EA feedback containing augmented high-frequency errors. Stabilogram diffusion analysis was used to characterize force fluctuation dynamics. Also, the discharge behaviors of motor units and pooled motor unit coherence were assessed following the decomposition of multi-channel surface electromyography (EMG). EA produced different behavioral and neurophysiological impacts on young and older adults. Older adults exhibited inferior task accuracy with EA feedback than with typical visual feedback, but not young adults. Although stabilogram diffusion analysis revealed that EA led to a significant decrease in critical time points for both groups, EA potentiated the critical point of force fluctuations [Formula: see text], short-term effective diffusion coefficients (Ds), and short-term exponent scaling only for the older adults. Moreover, in older adults, EA added to the size of discharge variability of motor units and discharge regularity of cumulative discharge rate, but suppressed the pooled motor unit coherence in the 13-35 Hz band. Virtual EA alters the strategic balance between open-loop and closed-loop controls for force-tracking. Contrary to expectations, the prevailing use of closed-loop control with EA that contained high-frequency error information enhanced the motor unit discharge variability and undermined the force steadiness in the older group, concerning declines in physiological complexity in the neurobehavioral system and the common drive to the motoneuronal pool against force destabilization.

Variations in Static Force Control and Motor Unit Behavior with Error Amplification Feedback in the Elderly

PubMed Central

Chen, Yi-Ching; Lin, Linda L.; Lin, Yen-Ting; Hu, Chia-Ling; Hwang, Ing-Shiou

2017-01-01

Error amplification (EA) feedback is a promising approach to advance visuomotor skill. As error detection and visuomotor processing at short time scales decline with age, this study examined whether older adults could benefit from EA feedback that included higher-frequency information to guide a force-tracking task. Fourteen young and 14 older adults performed low-level static isometric force-tracking with visual guidance of typical visual feedback and EA feedback containing augmented high-frequency errors. Stabilogram diffusion analysis was used to characterize force fluctuation dynamics. Also, the discharge behaviors of motor units and pooled motor unit coherence were assessed following the decomposition of multi-channel surface electromyography (EMG). EA produced different behavioral and neurophysiological impacts on young and older adults. Older adults exhibited inferior task accuracy with EA feedback than with typical visual feedback, but not young adults. Although stabilogram diffusion analysis revealed that EA led to a significant decrease in critical time points for both groups, EA potentiated the critical point of force fluctuations <ΔFc2>, short-term effective diffusion coefficients (Ds), and short-term exponent scaling only for the older adults. Moreover, in older adults, EA added to the size of discharge variability of motor units and discharge regularity of cumulative discharge rate, but suppressed the pooled motor unit coherence in the 13–35 Hz band. Virtual EA alters the strategic balance between open-loop and closed-loop controls for force-tracking. Contrary to expectations, the prevailing use of closed-loop control with EA that contained high-frequency error information enhanced the motor unit discharge variability and undermined the force steadiness in the older group, concerning declines in physiological complexity in the neurobehavioral system and the common drive to the motoneuronal pool against force destabilization. PMID:29167637

The Sense of Agency Is More Sensitive to Manipulations of Outcome than Movement-Related Feedback Irrespective of Sensory Modality

PubMed Central

David, Nicole; Skoruppa, Stefan; Gulberti, Alessandro

2016-01-01

The sense of agency describes the ability to experience oneself as the agent of one's own actions. Previous studies of the sense of agency manipulated the predicted sensory feedback related either to movement execution or to the movement’s outcome, for example by delaying the movement of a virtual hand or the onset of a tone that resulted from a button press. Such temporal sensorimotor discrepancies reduce the sense of agency. It remains unclear whether movement-related feedback is processed differently than outcome-related feedback in terms of agency experience, especially if these types of feedback differ with respect to sensory modality. We employed a mixed-reality setup, in which participants tracked their finger movements by means of a virtual hand. They performed a single tap, which elicited a sound. The temporal contingency between the participants’ finger movements and (i) the movement of the virtual hand or (ii) the expected auditory outcome was systematically varied. In a visual control experiment, the tap elicited a visual outcome. For each feedback type and participant, changes in the sense of agency were quantified using a forced-choice paradigm and the Method of Constant Stimuli. Participants were more sensitive to delays of outcome than to delays of movement execution. This effect was very similar for visual or auditory outcome delays. Our results indicate different contributions of movement- versus outcome-related sensory feedback to the sense of agency, irrespective of the modality of the outcome. We propose that this differential sensitivity reflects the behavioral importance of assessing authorship of the outcome of an action. PMID:27536948

On the nature of unintentional action: a study of force/moment drifts during multifinger tasks.

PubMed

Parsa, Behnoosh; O'Shea, Daniel J; Zatsiorsky, Vladimir M; Latash, Mark L

2016-08-01

We explored the origins of unintentional changes in performance during accurate force production in isometric conditions seen after turning visual feedback off. The idea of control with referent spatial coordinates suggests that these phenomena could result from drifts of the referent coordinate for the effector. Subjects performed accurate force/moment production tasks by pressing with the fingers of a hand on force sensors. Turning the visual feedback off resulted in slow drifts of both total force and total moment to lower magnitudes of these variables; these drifts were more pronounced in the right hand of the right-handed subjects. Drifts in individual finger forces could be in different direction; in particular, fingers that produced moments of force against the required total moment showed an increase in their forces. The force/moment drift was associated with a drop in the index of synergy stabilizing performance under visual feedback. The drifts in directions that changed performance (non-motor equivalent) and in directions that did not (motor equivalent) were of about the same magnitude. The results suggest that control with referent coordinates is associated with drifts of those referent coordinates toward the corresponding actual coordinates of the hand, a reflection of the natural tendency of physical systems to move toward a minimum of potential energy. The interaction between drifts of the hand referent coordinate and referent orientation leads to counterdirectional drifts in individual finger forces. The results also demonstrate that the sensory information used to create multifinger synergies is necessary for their presence over the task duration. Copyright © 2016 the American Physiological Society.

Effects of kinesthetic and cutaneous stimulation during the learning of a viscous force field.

PubMed

Rosati, Giulio; Oscari, Fabio; Pacchierotti, Claudio; Prattichizzo, Domenico

2014-01-01

Haptic stimulation can help humans learn perceptual motor skills, but the precise way in which it influences the learning process has not yet been clarified. This study investigates the role of the kinesthetic and cutaneous components of haptic feedback during the learning of a viscous curl field, taking also into account the influence of visual feedback. We present the results of an experiment in which 17 subjects were asked to make reaching movements while grasping a joystick and wearing a pair of cutaneous devices. Each device was able to provide cutaneous contact forces through a moving platform. The subjects received visual feedback about joystick's position. During the experiment, the system delivered a perturbation through (1) full haptic stimulation, (2) kinesthetic stimulation alone, (3) cutaneous stimulation alone, (4) altered visual feedback, or (5) altered visual feedback plus cutaneous stimulation. Conditions 1, 2, and 3 were also tested with the cancellation of the visual feedback of position error. Results indicate that kinesthetic stimuli played a primary role during motor adaptation to the viscous field, which is a fundamental premise to motor learning and rehabilitation. On the other hand, cutaneous stimulation alone appeared not to bring significant direct or adaptation effects, although it helped in reducing direct effects when used in addition to kinesthetic stimulation. The experimental conditions with visual cancellation of position error showed slower adaptation rates, indicating that visual feedback actively contributes to the formation of internal models. However, modest learning effects were detected when the visual information was used to render the viscous field.

Network interactions underlying mirror feedback in stroke: A dynamic causal modeling study.

PubMed

Saleh, Soha; Yarossi, Mathew; Manuweera, Thushini; Adamovich, Sergei; Tunik, Eugene

2017-01-01

Mirror visual feedback (MVF) is potentially a powerful tool to facilitate recovery of disordered movement and stimulate activation of under-active brain areas due to stroke. The neural mechanisms underlying MVF have therefore been a focus of recent inquiry. Although it is known that sensorimotor areas can be activated via mirror feedback, the network interactions driving this effect remain unknown. The aim of the current study was to fill this gap by using dynamic causal modeling to test the interactions between regions in the frontal and parietal lobes that may be important for modulating the activation of the ipsilesional motor cortex during mirror visual feedback of unaffected hand movement in stroke patients. Our intent was to distinguish between two theoretical neural mechanisms that might mediate ipsilateral activation in response to mirror-feedback: transfer of information between bilateral motor cortices versus recruitment of regions comprising an action observation network which in turn modulate the motor cortex. In an event-related fMRI design, fourteen chronic stroke subjects performed goal-directed finger flexion movements with their unaffected hand while observing real-time visual feedback of the corresponding (veridical) or opposite (mirror) hand in virtual reality. Among 30 plausible network models that were tested, the winning model revealed significant mirror feedback-based modulation of the ipsilesional motor cortex arising from the contralesional parietal cortex, in a region along the rostral extent of the intraparietal sulcus. No winning model was identified for the veridical feedback condition. We discuss our findings in the context of supporting the latter hypothesis, that mirror feedback-based activation of motor cortex may be attributed to engagement of a contralateral (contralesional) action observation network. These findings may have important implications for identifying putative cortical areas, which may be targeted with non-invasive brain stimulation as a means of potentiating the effects of mirror training.

The Effects of Mirror Feedback during Target Directed Movements on Ipsilateral Corticospinal Excitability

PubMed Central

Yarossi, Mathew; Manuweera, Thushini; Adamovich, Sergei V.; Tunik, Eugene

2017-01-01

Mirror visual feedback (MVF) training is a promising technique to promote activation in the lesioned hemisphere following stroke, and aid recovery. However, current outcomes of MVF training are mixed, in part, due to variability in the task undertaken during MVF. The present study investigated the hypothesis that movements directed toward visual targets may enhance MVF modulation of motor cortex (M1) excitability ipsilateral to the trained hand compared to movements without visual targets. Ten healthy subjects participated in a 2 × 2 factorial design in which feedback (veridical, mirror) and presence of a visual target (target present, target absent) for a right index-finger flexion task were systematically manipulated in a virtual environment. To measure M1 excitability, transcranial magnetic stimulation (TMS) was applied to the hemisphere ipsilateral to the trained hand to elicit motor evoked potentials (MEPs) in the untrained first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles at rest prior to and following each of four 2-min blocks of 30 movements (B1–B4). Targeted movement kinematics without visual feedback was measured before and after training to assess learning and transfer. FDI MEPs were decreased in B1 and B2 when movements were made with veridical feedback and visual targets were absent. FDI MEPs were decreased in B2 and B3 when movements were made with mirror feedback and visual targets were absent. FDI MEPs were increased in B3 when movements were made with mirror feedback and visual targets were present. Significant MEP changes were not present for the uninvolved ADM, suggesting a task-specific effect. Analysis of kinematics revealed learning occurred in visual target-directed conditions, but transfer was not sensitive to mirror feedback. Results are discussed with respect to current theoretical mechanisms underlying MVF-induced changes in ipsilateral excitability. PMID:28553218

Effect of visuomotor-map uncertainty on visuomotor adaptation.

PubMed

Saijo, Naoki; Gomi, Hiroaki

2012-03-01

Vision and proprioception contribute to generating hand movement. If a conflict between the visual and proprioceptive feedback of hand position is given, reaching movement is disturbed initially but recovers after training. Although previous studies have predominantly investigated the adaptive change in the motor output, it is unclear whether the contributions of visual and proprioceptive feedback controls to the reaching movement are modified by visuomotor adaptation. To investigate this, we focused on the change in proprioceptive feedback control associated with visuomotor adaptation. After the adaptation to gradually introduce visuomotor rotation, the hand reached the shifted position of the visual target to move the cursor to the visual target correctly. When the cursor feedback was occasionally eliminated (probe trial), the end point of the hand movement was biased in the visual-target direction, while the movement was initiated in the adapted direction, suggesting the incomplete adaptation of proprioceptive feedback control. Moreover, after the learning of uncertain visuomotor rotation, in which the rotation angle was randomly fluctuated on a trial-by-trial basis, the end-point bias in the probe trial increased, but the initial movement direction was not affected, suggesting a reduction in the adaptation level of proprioceptive feedback control. These results suggest that the change in the relative contribution of visual and proprioceptive feedback controls to the reaching movement in response to the visuomotor-map uncertainty is involved in visuomotor adaptation, whereas feedforward control might adapt in a manner different from that of the feedback control.

Fixed-base simulator study of the effect of time delays in visual cues on pilot tracking performance

NASA Technical Reports Server (NTRS)

Queijo, M. J.; Riley, D. R.

1975-01-01

Factors were examined which determine the amount of time delay acceptable in the visual feedback loop in flight simulators. Acceptable time delays are defined as delays which significantly affect neither the results nor the manner in which the subject 'flies' the simulator. The subject tracked a target aircraft as it oscillated sinusoidally in a vertical plane only. The pursuing aircraft was permitted five degrees of freedom. Time delays of from 0.047 to 0.297 second were inserted in the visual feedback loop. A side task was employed to maintain the workload constant and to insure that the pilot was fully occupied during the experiment. Tracking results were obtained for 17 aircraft configurations having different longitudinal short-period characteristics. Results show a positive correlation between improved handling qualities and a longer acceptable time delay.

Learning a visuomotor rotation: simultaneous visual and proprioceptive information is crucial for visuomotor remapping.

PubMed

Shabbott, Britne A; Sainburg, Robert L

2010-05-01

Visuomotor adaptation is mediated by errors between intended and sensory-detected arm positions. However, it is not clear whether visual-based errors that are shown during the course of motion lead to qualitatively different or more efficient adaptation than errors shown after movement. For instance, continuous visual feedback mediates online error corrections, which may facilitate or inhibit the adaptation process. We addressed this question by manipulating the timing of visual error information and task instructions during a visuomotor adaptation task. Subjects were exposed to a visuomotor rotation, during which they received continuous visual feedback (CF) of hand position with instructions to correct or not correct online errors, or knowledge-of-results (KR), provided as a static hand-path at the end of each trial. Our results showed that all groups improved performance with practice, and that online error corrections were inconsequential to the adaptation process. However, in contrast to the CF groups, the KR group showed relatively small reductions in mean error with practice, increased inter-trial variability during rotation exposure, and more limited generalization across target distances and workspace. Further, although the KR group showed improved performance with practice, after-effects were minimal when the rotation was removed. These findings suggest that simultaneous visual and proprioceptive information is critical in altering neural representations of visuomotor maps, although delayed error information may elicit compensatory strategies to offset perturbations.

Boosting the Motor Outcome of the Untrained Hand by Action Observation: Mirror Visual Feedback, Video Therapy, or Both Combined-What Is More Effective?

PubMed

Bähr, Florian; Ritter, Alexander; Seidel, Gundula; Puta, Christian; Gabriel, Holger H W; Hamzei, Farsin

2018-01-01

Action observation (AO) allows access to a network that processes visuomotor and sensorimotor inputs and is believed to be involved in observational learning of motor skills. We conducted three consecutive experiments to examine the boosting effect of AO on the motor outcome of the untrained hand by either mirror visual feedback (MVF), video therapy (VT), or a combination of both. In the first experiment, healthy participants trained either with MVF or without mirror feedback while in the second experiment, participants either trained with VT or observed animal videos. In the third experiment, participants first observed video clips that were followed by either training with MVF or training without mirror feedback. The outcomes for the untrained hand were quantified by scores from five motor tasks. The results demonstrated that MVF and VT significantly increase the motor performance of the untrained hand by the use of AO. We found that MVF was the most effective approach to increase the performance of the target effector. On the contrary, the combination of MVF and VT turns out to be less effective looking from clinical perspective. The gathered results suggest that action-related motor competence with the untrained hand is acquired by both mirror-based and video-based AO.

Boosting the Motor Outcome of the Untrained Hand by Action Observation: Mirror Visual Feedback, Video Therapy, or Both Combined—What Is More Effective?

PubMed Central

Ritter, Alexander; Seidel, Gundula; Puta, Christian; Gabriel, Holger H. W.; Hamzei, Farsin

2018-01-01

Action observation (AO) allows access to a network that processes visuomotor and sensorimotor inputs and is believed to be involved in observational learning of motor skills. We conducted three consecutive experiments to examine the boosting effect of AO on the motor outcome of the untrained hand by either mirror visual feedback (MVF), video therapy (VT), or a combination of both. In the first experiment, healthy participants trained either with MVF or without mirror feedback while in the second experiment, participants either trained with VT or observed animal videos. In the third experiment, participants first observed video clips that were followed by either training with MVF or training without mirror feedback. The outcomes for the untrained hand were quantified by scores from five motor tasks. The results demonstrated that MVF and VT significantly increase the motor performance of the untrained hand by the use of AO. We found that MVF was the most effective approach to increase the performance of the target effector. On the contrary, the combination of MVF and VT turns out to be less effective looking from clinical perspective. The gathered results suggest that action-related motor competence with the untrained hand is acquired by both mirror-based and video-based AO. PMID:29849570

Computer-aided training sensorimotor cortex functions in humans before the upper limb transplantation using virtual reality and sensory feedback.

PubMed

Kurzynski, Marek; Jaskolska, Anna; Marusiak, Jaroslaw; Wolczowski, Andrzej; Bierut, Przemyslaw; Szumowski, Lukasz; Witkowski, Jerzy; Kisiel-Sajewicz, Katarzyna

2017-08-01

One of the biggest problems of upper limb transplantation is lack of certainty as to whether a patient will be able to control voluntary movements of transplanted hands. Based on findings of the recent research on brain cortex plasticity, a premise can be drawn that mental training supported with visual and sensory feedback can cause structural and functional reorganization of the sensorimotor cortex, which leads to recovery of function associated with the control of movements performed by the upper limbs. In this study, authors - based on the above observations - propose the computer-aided training (CAT) system, which generating visual and sensory stimuli, should enhance the effectiveness of mental training applied to humans before upper limb transplantation. The basis for the concept of computer-aided training system is a virtual hand whose reaching and grasping movements the trained patient can observe on the VR headset screen (visual feedback) and whose contact with virtual objects the patient can feel as a touch (sensory feedback). The computer training system is composed of three main components: (1) the system generating 3D virtual world in which the patient sees the virtual limb from the perspective as if it were his/her own hand; (2) sensory feedback transforming information about the interaction of the virtual hand with the grasped object into mechanical vibration; (3) the therapist's panel for controlling the training course. Results of the case study demonstrate that mental training supported with visual and sensory stimuli generated by the computer system leads to a beneficial change of the brain activity related to motor control of the reaching in the patient with bilateral upper limb congenital transverse deficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Noise destroys feedback enhanced figure-ground segmentation but not feedforward figure-ground segmentation.

PubMed

Romeo, August; Arall, Marina; Supèr, Hans

2012-01-01

Figure-ground (FG) segmentation is the separation of visual information into background and foreground objects. In the visual cortex, FG responses are observed in the late stimulus response period, when neurons fire in tonic mode, and are accompanied by a switch in cortical state. When such a switch does not occur, FG segmentation fails. Currently, it is not known what happens in the brain on such occasions. A biologically plausible feedforward spiking neuron model was previously devised that performed FG segmentation successfully. After incorporating feedback the FG signal was enhanced, which was accompanied by a change in spiking regime. In a feedforward model neurons respond in a bursting mode whereas in the feedback model neurons fired in tonic mode. It is known that bursts can overcome noise, while tonic firing appears to be much more sensitive to noise. In the present study, we try to elucidate how the presence of noise can impair FG segmentation, and to what extent the feedforward and feedback pathways can overcome noise. We show that noise specifically destroys the feedback enhanced FG segmentation and leaves the feedforward FG segmentation largely intact. Our results predict that noise produces failure in FG perception.

Noise destroys feedback enhanced figure-ground segmentation but not feedforward figure-ground segmentation

PubMed Central

Romeo, August; Arall, Marina; Supèr, Hans

2012-01-01

Figure-ground (FG) segmentation is the separation of visual information into background and foreground objects. In the visual cortex, FG responses are observed in the late stimulus response period, when neurons fire in tonic mode, and are accompanied by a switch in cortical state. When such a switch does not occur, FG segmentation fails. Currently, it is not known what happens in the brain on such occasions. A biologically plausible feedforward spiking neuron model was previously devised that performed FG segmentation successfully. After incorporating feedback the FG signal was enhanced, which was accompanied by a change in spiking regime. In a feedforward model neurons respond in a bursting mode whereas in the feedback model neurons fired in tonic mode. It is known that bursts can overcome noise, while tonic firing appears to be much more sensitive to noise. In the present study, we try to elucidate how the presence of noise can impair FG segmentation, and to what extent the feedforward and feedback pathways can overcome noise. We show that noise specifically destroys the feedback enhanced FG segmentation and leaves the feedforward FG segmentation largely intact. Our results predict that noise produces failure in FG perception. PMID:22934028

Randomized crossover trial of a pressure sensing visual feedback system to improve mask fitting in noninvasive ventilation.

PubMed

Brill, Anne-Kathrin; Moghal, Mohammad; Morrell, Mary J; Simonds, Anita K

2017-10-01

A good mask fit, avoiding air leaks and pressure effects on the skin are key elements for a successful noninvasive ventilation (NIV). However, delivering practical training for NIV is challenging, and it takes time to build experience and competency. This study investigated whether a pressure sensing system with real-time visual feedback improved mask fitting. During an NIV training session, 30 healthcare professionals (14 trained in mask fitting and 16 untrained) performed two mask fittings on the same healthy volunteer in a randomized order: one using standard mask-fitting procedures and one with additional visual feedback on mask pressure on the nasal bridge. Participants were required to achieve a mask fit with low mask pressure and minimal air leak (<10 L/min). Pressure exerted on the nasal bridge, perceived comfort of mask fit and staff- confidence were measured. Compared with standard mask fitting, a lower pressure was exerted on the nasal bridge using the feedback system (71.1 ± 17.6 mm Hg vs 63.2 ± 14.6 mm Hg, P < 0.001). Both untrained and trained healthcare professionals were able to reduce the pressure on the nasal bridge (74.5 ± 21.2 mm Hg vs 66.1 ± 17.4 mm Hg, P = 0.023 and 67 ± 12.1 mm Hg vs 60 ± 10.6 mm Hg, P = 0.002, respectively) using the feedback system and self-rated confidence increased in the untrained group. Real-time visual feedback using pressure sensing technology supported healthcare professionals during mask-fitting training, resulted in a lower pressure on the skin and better mask fit for the volunteer, with increased staff confidence. © 2017 Asian Pacific Society of Respirology.

Use of cues in virtual reality depends on visual feedback.

PubMed

Fulvio, Jacqueline M; Rokers, Bas

2017-11-22

3D motion perception is of central importance to daily life. However, when tested in laboratory settings, sensitivity to 3D motion signals is found to be poor, leading to the view that heuristics and prior assumptions are critical for 3D motion perception. Here we explore an alternative: sensitivity to 3D motion signals is context-dependent and must be learned based on explicit visual feedback in novel environments. The need for action-contingent visual feedback is well-established in the developmental literature. For example, young kittens that are passively moved through an environment, but unable to move through it themselves, fail to develop accurate depth perception. We find that these principles also obtain in adult human perception. Observers that do not experience visual consequences of their actions fail to develop accurate 3D motion perception in a virtual reality environment, even after prolonged exposure. By contrast, observers that experience the consequences of their actions improve performance based on available sensory cues to 3D motion. Specifically, we find that observers learn to exploit the small motion parallax cues provided by head jitter. Our findings advance understanding of human 3D motion processing and form a foundation for future study of perception in virtual and natural 3D environments.

Haptically facilitated bimanual training combined with augmented visual feedback in moderate to severe hemiplegia.

PubMed

Boos, Amy; Qiu, Qinyin; Fluet, Gerard G; Adamovich, Sergei V

2011-01-01

This study describes the design and feasibility testing of a hand rehabilitation system that provides haptic assistance for hand opening in moderate to severe hemiplegia while subjects attempt to perform bilateral hand movements. A cable-actuated exoskeleton robot assists the subjects in performing impaired finger movements but is controlled by movement of the unimpaired hand. In an attempt to combine the neurophysiological stimuli of bilateral movement and action observation during training, visual feedback of the impaired hand is replaced by feedback of the unimpaired hand, either by using a sagittaly oriented mirror or a virtual reality setup with a pair of virtual hands presented on a flat screen controlled with movement of the unimpaired hand, providing a visual image of their paretic hand moving normally. Joint angles for both hands are measured using data gloves. The system is programmed to maintain a symmetrical relationship between the two hands as they respond to commands to open and close simultaneously. Three persons with moderate to severe hemiplegia secondary to stroke trained with the system for eight, 30 to 60 minute sessions without adverse events. Each demonstrated positive motor adaptations to training. The system was well tolerated by persons with moderate to severe upper extremity hemiplegia. Further testing of its effects on motor ability with a broader range of clinical presentations is indicated.

Movement preparation and execution: differential functional activation patterns after traumatic brain injury.

PubMed

Gooijers, Jolien; Beets, Iseult A M; Albouy, Genevieve; Beeckmans, Kurt; Michiels, Karla; Sunaert, Stefan; Swinnen, Stephan P

2016-09-01

Years following the insult, patients with traumatic brain injury often experience persistent motor control problems, including bimanual coordination deficits. Previous studies revealed that such deficits are related to brain structural white and grey matter abnormalities. Here, we assessed, for the first time, cerebral functional activation patterns during bimanual movement preparation and performance in patients with traumatic brain injury, using functional magnetic resonance imaging. Eighteen patients with moderate-to-severe traumatic brain injury (10 females; aged 26.3 years, standard deviation = 5.2; age range: 18.4-34.6 years) and 26 healthy young adults (15 females; aged 23.6 years, standard deviation = 3.8; age range: 19.5-33 years) performed a complex bimanual tracking task, divided into a preparation (2 s) and execution (9 s) phase, and executed either in the presence or absence of augmented visual feedback. Performance on the bimanual tracking task, expressed as the average target error, was impaired for patients as compared to controls (P < 0.001) and for trials in the absence as compared to the presence of augmented visual feedback (P < 0.001). At the cerebral level, movement preparation was characterized by reduced neural activation in the patient group relative to the control group in frontal (bilateral superior frontal gyrus, right dorsolateral prefrontal cortex), parietal (left inferior parietal lobe) and occipital (right striate and extrastriate visual cortex) areas (P's < 0.05). During the execution phase, however, the opposite pattern emerged, i.e. traumatic brain injury patients showed enhanced activations compared with controls in frontal (left dorsolateral prefrontal cortex, left lateral anterior prefrontal cortex, and left orbitofrontal cortex), parietal (bilateral inferior parietal lobe, bilateral superior parietal lobe, right precuneus, right primary somatosensory cortex), occipital (right striate and extrastriate visual cortices), and subcortical (left cerebellum crus II) areas (P's < 0.05). Moreover, a significant interaction effect between Feedback Condition and Group in the primary motor area (bilaterally) (P < 0.001), the cerebellum (left) (P < 0.001) and caudate (left) (P < 0.05), revealed that controls showed less overlap of activation patterns accompanying the two feedback conditions than patients with traumatic brain injury (i.e. decreased neural differentiation). In sum, our findings point towards poorer predictive control in traumatic brain injury patients in comparison to controls. Moreover, irrespective of the feedback condition, overactivations were observed in traumatically brain injured patients during movement execution, pointing to more controlled processing of motor task performance. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Visual Feedback of the Non-Moving Limb Improves Active Joint-Position Sense of the Impaired Limb in Spastic Hemiparetic Cerebral Palsy

ERIC Educational Resources Information Center

Smorenburg, Ana R. P.; Ledebt, Annick; Deconinck, Frederik J. A.; Savelsbergh, Geert J. P.

2011-01-01

This study examined the active joint-position sense in children with Spastic Hemiparetic Cerebral Palsy (SHCP) and the effect of static visual feedback and static mirror visual feedback, of the non-moving limb, on the joint-position sense. Participants were asked to match the position of one upper limb with that of the contralateral limb. The task…

Reducing Trunk Compensation in Stroke Survivors: A Randomized Crossover Trial Comparing Visual and Force Feedback Modalities.

PubMed

Valdés, Bulmaro Adolfo; Schneider, Andrea Nicole; Van der Loos, H F Machiel

2017-10-01

To investigate whether the compensatory trunk movements of stroke survivors observed during reaching tasks can be decreased by force and visual feedback, and to examine whether one of these feedback modalities is more efficacious than the other in reducing this compensatory tendency. Randomized crossover trial. University research laboratory. Community-dwelling older adults (N=15; 5 women; mean age, 64±11y) with hemiplegia from nontraumatic hemorrhagic or ischemic stroke (>3mo poststroke), recruited from stroke recovery groups, the research group's website, and the community. In a single session, participants received augmented feedback about their trunk compensation during a bimanual reaching task. Visual feedback (60 trials) was delivered through a computer monitor, and force feedback (60 trials) was delivered through 2 robotic devices. Primary outcome measure included change in anterior trunk displacement measured by motion tracking camera. Secondary outcomes included trunk rotation, index of curvature (measure of straightness of hands' path toward target), root mean square error of hands' movement (differences between hand position on every iteration of the program), completion time for each trial, and posttest questionnaire to evaluate users' experience and system's usability. Both visual (-45.6% [45.8 SD] change from baseline, P=.004) and force (-41.1% [46.1 SD], P=.004) feedback were effective in reducing trunk compensation. Scores on secondary outcome measures did not improve with either feedback modality. Neither feedback condition was superior. Visual and force feedback show promise as 2 modalities that could be used to decrease trunk compensation in stroke survivors during reaching tasks. It remains to be established which one of these 2 feedback modalities is more efficacious than the other as a cue to reduce compensatory trunk movement. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Watch what you type: the role of visual feedback from the screen and hands in skilled typewriting.

PubMed

Snyder, Kristy M; Logan, Gordon D; Yamaguchi, Motonori

2015-01-01

Skilled typing is controlled by two hierarchically structured processing loops (Logan & Crump, 2011): The outer loop, which produces words, commands the inner loop, which produces keystrokes. Here, we assessed the interplay between the two loops by investigating how visual feedback from the screen (responses either were or were not echoed on the screen) and the hands (the hands either were or were not covered with a box) influences the control of skilled typing. Our results indicated, first, that the reaction time of the first keystroke was longer when responses were not echoed than when they were. Also, the interkeystroke interval (IKSI) was longer when the hands were covered than when they were visible, and the IKSI for responses that were not echoed was longer when explicit error monitoring was required (Exp. 2) than when it was not required (Exp. 1). Finally, explicit error monitoring was more accurate when response echoes were present than when they were absent, and implicit error monitoring (i.e., posterror slowing) was not influenced by visual feedback from the screen or the hands. These findings suggest that the outer loop adjusts the inner-loop timing parameters to compensate for reductions in visual feedback. We suggest that these adjustments are preemptive control strategies designed to execute keystrokes more cautiously when visual feedback from the hands is absent, to generate more cautious motor programs when visual feedback from the screen is absent, and to enable enough time for the outer loop to monitor keystrokes when visual feedback from the screen is absent and explicit error reports are required.

Giving feedback in medical teaching: a case of lung function laboratory/spirometry.

PubMed

Meo, Sultan Ayoub

2013-01-01

Feedback in medical teaching is an important part of medical education, it encourages and enhances the learners' knowledge, skills and professional performance at various stages of their schooling. A constructive feedback enhances the awareness of strength and areas for improvement. An adequate, meaningful and fruitful feedback needs motivation, emphasis, objectivity, expertise, and active participation in the session. Before giving feedback, the instructor should be well prepared and must have practice on the task. The instructor should utilize all means such as good oral presentation, eye contact, visual cues, utilize body language to actively involve the learners in a session, all these activities enhance the knowledge, skill and attitude of the learners. The aim of this commentary is to highlight the basic issues in giving an appropriate feedback in medical teaching with special emphasis on a lung function laboratory / Spirometry.

Advanced control techniques for teleoperation in earth orbit

NASA Technical Reports Server (NTRS)

Bejczy, A. K.; Brooks, T. L.

1980-01-01

Emerging teleoperation tasks in space invite advancements in teleoperator control technology. This paper briefly summarizes the generic issues related to earth orbital applications of teleoperators, and describes teleoperator control technology development work including visual and non-visual sensors and displays, kinesthetic feedback and computer-aided controls. Performance experiments were carried out using sensor and computer aided controls with promising results which are briefly summarized.

The Classroom Check-up: A Classwide Teacher Consultation Model for Increasing Praise and Decreasing Disruptive Behavior

PubMed Central

Reinke, Wendy M.; Lewis-Palmer, Teri; Merrell, Kenneth

2008-01-01

School-based consultation typically focuses on individual student problems and on a small number of students rather than on changing the classroom system. The Classroom Check-up (CCU) was developed as a classwide consultation model to address the need for classroom level support while minimizing treatment integrity problems common to school-based consultation. The purpose of the study was to evaluate the effects of the CCU and Visual Performance Feedback on teacher and student behavior. Results indicated that implementation of the CCU plus Visual Performance Feedback increased teacher implementation of classroom management strategies, including increased use of praise, use of behavior specific praise, and decreased use of reprimands. Further, these changes in teacher behavior contributed to decreases in classroom disruptive behavior. The results are encouraging because they suggest that consultation at the classroom level can create meaningful teacher and student behavior change. PMID:19122805

Visual Perspective and Feedback Guidance for VR Free-Throw Training.

PubMed

Covaci, Alexandra; Olivier, Anne-Hélène; Multon, Franck

2015-01-01

Accurate distance perception and natural interactions are mandatory conditions when training precision aiming tasks in VR. However, many factors specific to virtual environments (VEs) lead to differences in the way users execute a motor task in VR versus the real world. To investigate these differences, the authors performed a study on basketball beginners' free-throw performance in VEs under different visual conditions. Although the success rate is not statistically different, some adaptations occurred in the way the users performed the task, depending on the visual conditions. In the third-person perspective visual condition, the release parameters indicate that the users more accurately estimated distance to target. Adding visual guidance information (gradual depth information showing the ideal ball trajectory) also led to more natural motor behavior. The final aim of this study was to develop a reliable basketball free-throw training system in VEs, so the authors compared beginners' performances in VR with experts' models of performance. Their results show that most of the performance variables tended to evolve closer to the experts' performance during the training in the VE.

Structure Learning in Bayesian Sensorimotor Integration

PubMed Central

Genewein, Tim; Hez, Eduard; Razzaghpanah, Zeynab; Braun, Daniel A.

2015-01-01

Previous studies have shown that sensorimotor processing can often be described by Bayesian learning, in particular the integration of prior and feedback information depending on its degree of reliability. Here we test the hypothesis that the integration process itself can be tuned to the statistical structure of the environment. We exposed human participants to a reaching task in a three-dimensional virtual reality environment where we could displace the visual feedback of their hand position in a two dimensional plane. When introducing statistical structure between the two dimensions of the displacement, we found that over the course of several days participants adapted their feedback integration process in order to exploit this structure for performance improvement. In control experiments we found that this adaptation process critically depended on performance feedback and could not be induced by verbal instructions. Our results suggest that structural learning is an important meta-learning component of Bayesian sensorimotor integration. PMID:26305797

Cortical feedback signals generalise across different spatial frequencies of feedforward inputs.

PubMed

Revina, Yulia; Petro, Lucy S; Muckli, Lars

2017-09-22

Visual processing in cortex relies on feedback projections contextualising feedforward information flow. Primary visual cortex (V1) has small receptive fields and processes feedforward information at a fine-grained spatial scale, whereas higher visual areas have larger, spatially invariant receptive fields. Therefore, feedback could provide coarse information about the global scene structure or alternatively recover fine-grained structure by targeting small receptive fields in V1. We tested if feedback signals generalise across different spatial frequencies of feedforward inputs, or if they are tuned to the spatial scale of the visual scene. Using a partial occlusion paradigm, functional magnetic resonance imaging (fMRI) and multivoxel pattern analysis (MVPA) we investigated whether feedback to V1 contains coarse or fine-grained information by manipulating the spatial frequency of the scene surround outside an occluded image portion. We show that feedback transmits both coarse and fine-grained information as it carries information about both low (LSF) and high spatial frequencies (HSF). Further, feedback signals containing LSF information are similar to feedback signals containing HSF information, even without a large overlap in spatial frequency bands of the HSF and LSF scenes. Lastly, we found that feedback carries similar information about the spatial frequency band across different scenes. We conclude that cortical feedback signals contain information which generalises across different spatial frequencies of feedforward inputs. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Effects of visual feedback with a mirror on balance ability in patients with stroke.

PubMed

In, Tae-Sung; Cha, Yu-Ri; Jung, Jin-Hwa; Jung, Kyoung-Sim

2016-01-01

[Purpose] This study aimed to examine the effects of a visual feedback obtained from a mirror on balance ability during quiet standing in patients with stroke. [Subjects] Fifteen patients with stroke (9 males, 6 females) enrolled in the study. [Methods] Experimental trials (duration, 20s) included three visual conditions (eyes closed, eyes open, and mirror feedback) and two support surface conditions (stable, and unstable). Center of pressure (COP) displacements in the mediolateral and anteroposterior directions were recorded using a force platform. [Results] No effect of condition was observed along all directions on the stable surface. An effect of condition was observed on the unstable surface, with a smaller mediolateral COP distance in the mirror feedback as compared to the other two conditions. Similar results were observed for the COP speed. [Conclusion] Visual feedback from a mirror is beneficial for improving balance ability during quiet standing on an unstable surface in patients with stroke.

Biased Feedback in Spatial Recall Yields a Violation of Delta Rule Learning

PubMed Central

Lipinski, John; Spencer, John P.; Samuelson, Larissa K.

2010-01-01

This study investigates whether inductive processes influencing spatial memory performance generalize to supervised learning scenarios with differential feedback. After providing a location memory response in a spatial recall task, participants received visual feedback showing the target location. In critical blocks, feedback was systematically biased either 4° towards the vertical axis (Towards condition) or 4° further away from the vertical axis (Away condition). Results showed that the weaker teaching signal (i.e., a smaller difference between the remembered location and the feedback location) in the Away condition produced a stronger experience-dependent change over blocks than in the Towards condition. This violates delta rule learning. Subsequent simulations of the Dynamic Field Theory of spatial cognition provide a theoretically unified account of these results. PMID:20702881

Biased feedback in spatial recall yields a violation of delta rule learning.

PubMed

Lipinski, John; Spencer, John P; Samuelson, Larissa K

2010-08-01

This study investigates whether inductive processes influencing spatial memory performance generalize to supervised learning scenarios with differential feedback. After providing a location memory response in a spatial recall task, participants received visual feedback showing the target location. In critical blocks, feedback was systematically biased either 4 degrees toward the vertical axis (toward condition) or 4 degrees farther away from the vertical axis (away condition). Results showed that the weaker teaching signal (i.e., a smaller difference between the remembered location and the feedback location) produced a stronger experience-dependent change over blocks in the away condition than in the toward condition. This violates delta rule learning. Subsequent simulations of the dynamic field theory of spatial cognition provide a theoretically unified account of these results.

Neural Adaptations Associated with Interlimb Transfer in a Ballistic Wrist Flexion Task

PubMed Central

Ruddy, Kathy L.; Rudolf, Anne K.; Kalkman, Barbara; King, Maedbh; Daffertshofer, Andreas; Carroll, Timothy J.; Carson, Richard G.

2016-01-01

Cross education is the process whereby training of one limb gives rise to increases in the subsequent performance of its opposite counterpart. The execution of many unilateral tasks is associated with increased excitability of corticospinal projections from primary motor cortex (M1) to the opposite limb. It has been proposed that these effects are causally related. Our aim was to establish whether changes in corticospinal excitability (CSE) arising from prior training of the opposite limb determine levels of interlimb transfer. We used three vision conditions shown previously to modulate the excitability of corticospinal projections to the inactive (right) limb during wrist flexion movements performed by the training (left) limb. These were: (1) mirrored visual feedback of the training limb; (2) no visual feedback of either limb; and (3) visual feedback of the inactive limb. Training comprised 300 discrete, ballistic wrist flexion movements executed as rapidly as possible. Performance of the right limb on the same task was assessed prior to, at the mid point of, and following left limb training. There was no evidence that variations in the excitability of corticospinal projections (assessed by transcranial magnetic stimulation (TMS)) to the inactive limb were associated with, or predictive of, the extent of interlimb transfer that was expressed. There were however associations between alterations in muscle activation dynamics observed for the untrained limb, and the degree of positive transfer that arose from training of the opposite limb. The results suggest that the acute adaptations that mediate the bilateral performance gains realized through unilateral practice of this ballistic wrist flexion task are mediated by neural elements other than those within M1 that are recruited at rest by single-pulse TMS. PMID:27199722

Real-time computer-based visual feedback improves visual acuity in downbeat nystagmus - a pilot study.

PubMed

Teufel, Julian; Bardins, S; Spiegel, Rainer; Kremmyda, O; Schneider, E; Strupp, M; Kalla, R

2016-01-04

Patients with downbeat nystagmus syndrome suffer from oscillopsia, which leads to an unstable visual perception and therefore impaired visual acuity. The aim of this study was to use real-time computer-based visual feedback to compensate for the destabilizing slow phase eye movements. The patients were sitting in front of a computer screen with the head fixed on a chin rest. The eye movements were recorded by an eye tracking system (EyeSeeCam®). We tested the visual acuity with a fixed Landolt C (static) and during real-time feedback driven condition (dynamic) in gaze straight ahead and (20°) sideward gaze. In the dynamic condition, the Landolt C moved according to the slow phase eye velocity of the downbeat nystagmus. The Shapiro-Wilk test was used to test for normal distribution and one-way ANOVA for comparison. Ten patients with downbeat nystagmus were included in the study. Median age was 76 years and the median duration of symptoms was 6.3 years (SD +/- 3.1y). The mean slow phase velocity was moderate during gaze straight ahead (1.44°/s, SD +/- 1.18°/s) and increased significantly in sideward gaze (mean left 3.36°/s; right 3.58°/s). In gaze straight ahead, we found no difference between the static and feedback driven condition. In sideward gaze, visual acuity improved in five out of ten subjects during the feedback-driven condition (p = 0.043). This study provides proof of concept that non-invasive real-time computer-based visual feedback compensates for the SPV in DBN. Therefore, real-time visual feedback may be a promising aid for patients suffering from oscillopsia and impaired text reading on screen. Recent technological advances in the area of virtual reality displays might soon render this approach feasible in fully mobile settings.

Upper extremity rehabilitation of stroke: facilitation of corticospinal excitability using virtual mirror paradigm.

PubMed

Kang, Youn Joo; Park, Hae Kyung; Kim, Hyun Jung; Lim, Taeo; Ku, Jeonghun; Cho, Sangwoo; Kim, Sun I; Park, Eun Sook

2012-10-04

Several experimental studies in stroke patients suggest that mirror therapy and various virtual reality programs facilitate motor rehabilitation. However, the underlying mechanisms for these therapeutic effects have not been previously described. We attempted to delineate the changes in corticospinal excitability when individuals were asked to exercise their upper extremity using a real mirror and virtual mirror. Moreover, we attempted to delineate the role of visual modulation within the virtual environment that affected corticospinal excitability in healthy subjects and stroke patients. A total of 18 healthy subjects and 18 hemiplegic patients were enrolled into the study. Motor evoked potential (MEP)s from transcranial magnetic stimulation were recorded in the flexor carpi radialis of the non-dominant or affected upper extremity using three different conditions: (A) relaxation; (B) real mirror; and (C) virtual mirror. Moreover, we compared the MEPs from the virtual mirror paradigm using continuous visual feedback or intermittent visual feedback. The rates of amplitude increment and latency decrement of MEPs in both groups were higher during the virtual mirror task than during the real mirror. In healthy subjects and stroke patients, the virtual mirror task with intermittent visual feedback significantly facilitated corticospinal excitability of MEPs compared with continuous visual feedback. Corticospinal excitability was facilitated to a greater extent in the virtual mirror paradigm than in the real mirror and in intermittent visual feedback than in the continuous visual feedback, in both groups. This provides neurophysiological evidence supporting the application of the virtual mirror paradigm using various visual modulation technologies to upper extremity rehabilitation in stroke patients.

Upper extremity rehabilitation of stroke: Facilitation of corticospinal excitability using virtual mirror paradigm

PubMed Central

2012-01-01

Background Several experimental studies in stroke patients suggest that mirror therapy and various virtual reality programs facilitate motor rehabilitation. However, the underlying mechanisms for these therapeutic effects have not been previously described. Objectives We attempted to delineate the changes in corticospinal excitability when individuals were asked to exercise their upper extremity using a real mirror and virtual mirror. Moreover, we attempted to delineate the role of visual modulation within the virtual environment that affected corticospinal excitability in healthy subjects and stroke patients. Methods A total of 18 healthy subjects and 18 hemiplegic patients were enrolled into the study. Motor evoked potential (MEP)s from transcranial magnetic stimulation were recorded in the flexor carpi radialis of the non-dominant or affected upper extremity using three different conditions: (A) relaxation; (B) real mirror; and (C) virtual mirror. Moreover, we compared the MEPs from the virtual mirror paradigm using continuous visual feedback or intermittent visual feedback. Results The rates of amplitude increment and latency decrement of MEPs in both groups were higher during the virtual mirror task than during the real mirror. In healthy subjects and stroke patients, the virtual mirror task with intermittent visual feedback significantly facilitated corticospinal excitability of MEPs compared with continuous visual feedback. Conclusion Corticospinal excitability was facilitated to a greater extent in the virtual mirror paradigm than in the real mirror and in intermittent visual feedback than in the continuous visual feedback, in both groups. This provides neurophysiological evidence supporting the application of the virtual mirror paradigm using various visual modulation technologies to upper extremity rehabilitation in stroke patients. PMID:23035951

Visuomotor adaptation to a visual rotation is gravity dependent.

PubMed

Toma, Simone; Sciutti, Alessandra; Papaxanthis, Charalambos; Pozzo, Thierry

2015-03-15

Humans perform vertical and horizontal arm motions with different temporal patterns. The specific velocity profiles are chosen by the central nervous system by integrating the gravitational force field to minimize energy expenditure. However, what happens when a visuomotor rotation is applied, so that a motion performed in the horizontal plane is perceived as vertical? We investigated the dynamic of the adaptation of the spatial and temporal properties of a pointing motion during prolonged exposure to a 90° visuomotor rotation, where a horizontal movement was associated with a vertical visual feedback. We found that participants immediately adapted the spatial parameters of motion to the conflicting visual scene in order to keep their arm trajectory straight. In contrast, the initial symmetric velocity profiles specific for a horizontal motion were progressively modified during the conflict exposure, becoming more asymmetric and similar to those appropriate for a vertical motion. Importantly, this visual effect that increased with repetitions was not followed by a consistent aftereffect when the conflicting visual feedback was absent (catch and washout trials). In a control experiment we demonstrated that an intrinsic representation of the temporal structure of perceived vertical motions could provide the error signal allowing for this progressive adaptation of motion timing. These findings suggest that gravity strongly constrains motor learning and the reweighting process between visual and proprioceptive sensory inputs, leading to the selection of a motor plan that is suboptimal in terms of energy expenditure. Copyright © 2015 the American Physiological Society.

77 FR 12907 - Visual-Manual NHTSA Driver Distraction Guidelines for In-Vehicle Electronic Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-02

... impact of task performance while driving on driving safety and time-based acceptance criteria for... feedback). The proposed NHTSA Guidelines list certain secondary, non-driving related tasks that, based on... cannot be used by the driver to perform such tasks while the driver is driving. For all other secondary...

The Effect of Conscious Control on Handwriting in Children with Attention Deficit Hyperactivity Disorder

ERIC Educational Resources Information Center

Tucha, Oliver; Lange, Klaus W.

2005-01-01

Two experiments were performed regarding the effect of conscious control on handwriting fluency in healthy adults and ADHD children. First, 26 healthy students were asked to write a sentence under different conditions. The results indicate that automated handwriting movements are independent from visual feedback. Second, the writing performance of…

Selective effects of 5-HT2C receptor modulation on performance of a novel valence-probe visual discrimination task and probabilistic reversal learning in mice.

PubMed

Phillips, Benjamin U; Dewan, Sigma; Nilsson, Simon R O; Robbins, Trevor W; Heath, Christopher J; Saksida, Lisa M; Bussey, Timothy J; Alsiö, Johan

2018-04-22

Dysregulation of the serotonin (5-HT) system is a pathophysiological component in major depressive disorder (MDD), a condition closely associated with abnormal emotional responsivity to positive and negative feedback. However, the precise mechanism through which 5-HT tone biases feedback responsivity remains unclear. 5-HT2C receptors (5-HT2CRs) are closely linked with aspects of depressive symptomatology, including abnormalities in reinforcement processes and response to stress. Thus, we aimed to determine the impact of 5-HT2CR function on response to feedback in biased reinforcement learning. We used two touchscreen assays designed to assess the impact of positive and negative feedback on probabilistic reinforcement in mice, including a novel valence-probe visual discrimination (VPVD) and a probabilistic reversal learning procedure (PRL). Systemic administration of a 5-HT2CR agonist and antagonist resulted in selective changes in the balance of feedback sensitivity bias on these tasks. Specifically, on VPVD, SB 242084, the 5-HT2CR antagonist, impaired acquisition of a discrimination dependent on appropriate integration of positive and negative feedback. On PRL, SB 242084 at 1 mg/kg resulted in changes in behaviour consistent with reduced sensitivity to positive feedback. In contrast, WAY 163909, the 5-HT2CR agonist, resulted in changes associated with increased sensitivity to positive feedback and decreased sensitivity to negative feedback. These results suggest that 5-HT2CRs tightly regulate feedback sensitivity bias in mice with consequent effects on learning and cognitive flexibility and specify a framework for the influence of 5-HT2CRs on sensitivity to reinforcement.

Corticothalamic feedback enhances stimulus response precision in the visual system

PubMed Central

Andolina, Ian M.; Jones, Helen E.; Wang, Wei; Sillito, Adam M.

2007-01-01

There is a tightly coupled bidirectional interaction between visual cortex and visual thalamus [lateral geniculate nucleus (LGN)]. Using drifting sinusoidal grating stimuli, we compared the response of cells in the LGN with and without feedback from the visual cortex. Raster plots revealed a striking difference in the response pattern of cells with and without feedback. This difference was reflected in the results from computing vector sum plots and the ratio of zero harmonic to the fundamental harmonic of the fast Fourier transform (FFT) for these responses. The variability of responses assessed by using the Fano factor was also different for the two groups, with the cells without feedback showing higher variability. We examined the covariance of these measures between pairs of simultaneously recorded cells with and without feedback, and they were much more strongly positively correlated with feedback. We constructed orientation tuning curves from the central 5 ms in the raw cross-correlograms of the outputs of pairs of LGN cells, and these curves revealed much sharper tuning with feedback. We discuss the significance of these data for cortical function and suggest that the precision in stimulus-linked firing in the LGN appears as an emergent factor from the corticothalamic interaction. PMID:17237220

Integration of soft tissue model and open haptic device for medical training simulator

NASA Astrophysics Data System (ADS)

Akasum, G. F.; Ramdhania, L. N.; Suprijanto; Widyotriatmo, A.

2016-03-01

Minimally Invasive Surgery (MIS) has been widely used to perform any surgical procedures nowadays. Currently, MIS has been applied in some cases in Indonesia. Needle insertion is one of simple MIS procedure that can be used for some purposes. Before the needle insertion technique used in the real situation, it essential to train this type of medical student skills. The research has developed an open platform of needle insertion simulator with haptic feedback that providing the medical student a realistic feel encountered during the actual procedures. There are three main steps in build the training simulator, which are configure hardware system, develop a program to create soft tissue model and the integration of hardware and software. For evaluating its performance, haptic simulator was tested by 24 volunteers on a scenario of soft tissue model. Each volunteer must insert the needle on simulator until rearch the target point with visual feedback that visualized on the monitor. From the result it can concluded that the soft tissue model can bring the sensation of touch through the perceived force feedback on haptic actuator by looking at the different force in accordance with different stiffness in each layer.

Learning feedback and feedforward control in a mirror-reversed visual environment.

PubMed

Kasuga, Shoko; Telgen, Sebastian; Ushiba, Junichi; Nozaki, Daichi; Diedrichsen, Jörn

2015-10-01

When we learn a novel task, the motor system needs to acquire both feedforward and feedback control. Currently, little is known about how the learning of these two mechanisms relate to each other. In the present study, we tested whether feedforward and feedback control need to be learned separately, or whether they are learned as common mechanism when a new control policy is acquired. Participants were trained to reach to two lateral and one central target in an environment with mirror (left-right)-reversed visual feedback. One group was allowed to make online movement corrections, whereas the other group only received visual information after the end of the movement. Learning of feedforward control was assessed by measuring the accuracy of the initial movement direction to lateral targets. Feedback control was measured in the responses to sudden visual perturbations of the cursor when reaching to the central target. Although feedforward control improved in both groups, it was significantly better when online corrections were not allowed. In contrast, feedback control only adaptively changed in participants who received online feedback and remained unchanged in the group without online corrections. Our findings suggest that when a new control policy is acquired, feedforward and feedback control are learned separately, and that there may be a trade-off in learning between feedback and feedforward controllers. Copyright © 2015 the American Physiological Society.

Learning feedback and feedforward control in a mirror-reversed visual environment

PubMed Central

Kasuga, Shoko; Telgen, Sebastian; Ushiba, Junichi; Nozaki, Daichi

2015-01-01

When we learn a novel task, the motor system needs to acquire both feedforward and feedback control. Currently, little is known about how the learning of these two mechanisms relate to each other. In the present study, we tested whether feedforward and feedback control need to be learned separately, or whether they are learned as common mechanism when a new control policy is acquired. Participants were trained to reach to two lateral and one central target in an environment with mirror (left-right)-reversed visual feedback. One group was allowed to make online movement corrections, whereas the other group only received visual information after the end of the movement. Learning of feedforward control was assessed by measuring the accuracy of the initial movement direction to lateral targets. Feedback control was measured in the responses to sudden visual perturbations of the cursor when reaching to the central target. Although feedforward control improved in both groups, it was significantly better when online corrections were not allowed. In contrast, feedback control only adaptively changed in participants who received online feedback and remained unchanged in the group without online corrections. Our findings suggest that when a new control policy is acquired, feedforward and feedback control are learned separately, and that there may be a trade-off in learning between feedback and feedforward controllers. PMID:26245313

Optical sensor feedback assistive technology to enable patients to play an active role in the management of their body dynamics during radiotherapy treatment

NASA Astrophysics Data System (ADS)

Parkhurst, J. M.; Price, G. J.; Sharrock, P. J.; Stratford, J.; Moore, C. J.

2013-04-01

Patient motion during treatment is well understood as a prime factor limiting radiotherapy success, with the risks most pronounced in modern safety critical therapies promising the greatest benefit. In this paper we describe a real-time visual feedback device designed to help patients to actively manage their body position, pose and motion. In addition to technical device details, we present preliminary trial results showing that its use enables volunteers to successfully manage their respiratory motion. The device enables patients to view their live body surface measurements relative to a prior reference, operating on the concept that co-operative engagement with patients will both improve geometric conformance and remove their perception of isolation, in turn easing stress related motion. The device is driven by a real-time wide field optical sensor system developed at The Christie. Feedback is delivered through three intuitive visualization modes of hierarchically increasing display complexity. The device can be used with any suitable display technology; in the presented study we use both personal video glasses and a standard LCD projector. The performance characteristics of the system were measured, with the frame rate, throughput and latency of the feedback device being 22.4 fps, 47.0 Mbps, 109.8 ms, and 13.7 fps, 86.4 Mbps, 119.1 ms for single and three-channel modes respectively. The pilot study, using ten healthy volunteers over three sessions, shows that the use of visual feedback resulted in both a reduction in the participants' respiratory amplitude, and a decrease in their overall body motion variability.

A Neurophysiological examination of quality of learning in a feedback-based learning task.

PubMed

Arbel, Yael; Wu, Hao

2016-12-01

The efficiency with which one processes external feedback contributes to the speed and quality of one's learning. Previous findings that the feedback related negativity (FRN) event related potential (ERP) is modulated by learning outcomes suggested that this ERP reflects the extent to which feedback is used by the learner to improve performance. To further test this suggestion, we measured whether the FRN and the fronto-central positivity (FCP) that follows it are modulated by learning slopes, and as a function of individual differences in learning outcomes. Participants were tasked with learning names (non-words) of 42 novel objects in a two-choice feedback-based visual learning task. The items were divided into three sets of 14 items, each presented in five learning blocks and a sixth test block. Individual learning slopes based on performance on the task, as well as FRN and FCP slopes based on positive and negative feedback related activation in each block were created for 53 participants. Our data pointed to an interaction between slopes of the FRN elicited by negative feedback and learning slopes, such that a sharper decrease in the amplitude of the FRN to negative feedback was associated with sharper learning slopes. We further examined the predictive power of the FRN and FCP elicited in the training blocks on the learning outcomes as measured by performance on the test blocks. We found that small FRN to negative feedback, large FRN to positive feedback, and large FCP to negative feedback in the first training block predicted better learning outcomes. These results add to the growing evidence that the processes giving rise to the FRN and FCP are sensitive to individual differences in the extent to which feedback is used for learning. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neural mechanisms of limb position estimation in the primate brain.

PubMed

Shi, Ying; Buneo, Christopher A

2011-01-01

Understanding the neural mechanisms of limb position estimation is important both for comprehending the neural control of goal directed arm movements and for developing neuroprosthetic systems designed to replace lost limb function. Here we examined the role of area 5 of the posterior parietal cortex in estimating limb position based on visual and somatic (proprioceptive, efference copy) signals. Single unit recordings were obtained as monkeys reached to visual targets presented in a semi-immersive virtual reality environment. On half of the trials animals were required to maintain their limb position at these targets while receiving both visual and non-visual feedback of their arm position, while on the other trials visual feedback was withheld. When examined individually, many area 5 neurons were tuned to the position of the limb in the workspace but very few neurons modulated their firing rates based on the presence/absence of visual feedback. At the population level however decoding of limb position was somewhat more accurate when visual feedback was provided. These findings support a role for area 5 in limb position estimation but also suggest that visual signals regarding limb position are only weakly represented in this area, and only at the population level.

Effect of feedback techniques for lower back pain on gluteus maximus and oblique abdominal muscle activity and angle of pelvic rotation during the clam exercise.

PubMed

Koh, Eun-Kyung; Park, Kyue-Nam; Jung, Do-Young

2016-11-01

This study was conducted in order to determine the effect of feedback tools on activities of the gluteus maximus (Gmax) and oblique abdominal muscles and the angle of pelvic rotation during clam exercise (CE). Comparative study using repeated measures. University laboratory. Sixteen subjects with lower back pain. Each subject performed the CE without feedback, the CE using a pressure biofeedback unit (CE-PBU), and the CE with palpation and visual feedback (CE-PVF). Electromyographic (EMG) activity and the angles of pelvic rotation were measured using surface EMG and a three-dimensional motion-analysis system, respectively. One-way repeated-measures ANOVA followed by the Bonferroni post hoc test were used to compare the EMG activity in each muscle as well as the angle of pelvic rotation during the CE, CE-PBU, and CE-PVF. The results of post-hoc testing showed a significantly reduced angle of pelvic rotation and significantly more Gmax EMG activity during the CE-PVF compared with during the CE and CE-PBU. These findings suggest that palpation and visual feedback is effective for activating the Gmax and controlling pelvic rotation during the CE in subjects with lower back pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

Interactive Tools for Measuring Visual Scanning Performance and Reaction Time

PubMed Central

Seeanner, Julia; Hennessy, Sarah; Manganelli, Joseph; Crisler, Matthew; Rosopa, Patrick; Jenkins, Casey; Anderson, Michael; Drouin, Nathalie; Belle, Leah; Truesdail, Constance; Tanner, Stephanie

2017-01-01

Occupational therapists are constantly searching for engaging, high-technology interactive tasks that provide immediate feedback to evaluate and train clients with visual scanning deficits. This study examined the relationship between two tools: the VISION COACH™ interactive light board and the Functional Object Detection© (FOD) Advanced driving simulator scenario. Fifty-four healthy drivers, ages 21–66 yr, were divided into three age groups. Participants performed braking response and visual target (E) detection tasks of the FOD Advanced driving scenario, followed by two sets of three trials using the VISION COACH Full Field 60 task. Results showed no significant effect of age on FOD Advanced performance but a significant effect of age on VISION COACH performance. Correlations showed that participants’ performance on both braking and E detection tasks were significantly positively correlated with performance on the VISION COACH (.37 < r < .40, p < .01). These tools provide new options for therapists. PMID:28218598

Control of impact loading during distracted running before and after gait retraining in runners.

PubMed

Cheung, Roy T H; An, Winko W; Au, Ivan P H; Zhang, Janet H; Chan, Zoe Y S; MacPhail, Aislinn J

2018-07-01

Gait retraining using visual biofeedback has been reported to reduce impact loading in runners. However, most of the previous studies did not adequately examine the level of motor learning after training, as the modified gait pattern was not tested in a dual-task condition. Hence, this study sought to compare the landing peak positive acceleration (PPA) and vertical loading rates during distracted running before and after gait retraining. Sixteen recreational runners underwent a two-week visual biofeedback gait retraining program for impact loading reduction, with feedback on the PPA measured at heel. In the evaluation of PPA and vertical loading rates before and after the retraining, the participants performed a cognitive and verbal counting task while running. Repeated measures ANOVA indicated a significant interaction between feedback and training on PPA (F = 4.642; P = 0.048) but not vertical loading rates (F > 1.953; P > 0.067). Pairwise comparisons indicated a significantly lower PPA and vertical loading rates after gait retraining (P < 0.007; Cohen's d > 0.68). Visual feedback after gait retraining reduced PPA and vertical loading rates during distracted running (P < 0.033; Cohen's d > 0.36). Gait retraining is effective in lowering impact loading even when the runners are distracted. In dual-task situation, visual biofeedback provided beneficial influence on kinetics control after gait retraining.

Review of surgical robotics user interface: what is the best way to control robotic surgery?

PubMed

Simorov, Anton; Otte, R Stephen; Kopietz, Courtni M; Oleynikov, Dmitry

2012-08-01

As surgical robots begin to occupy a larger place in operating rooms around the world, continued innovation is necessary to improve our outcomes. A comprehensive review of current surgical robotic user interfaces was performed to describe the modern surgical platforms, identify the benefits, and address the issues of feedback and limitations of visualization. Most robots currently used in surgery employ a master/slave relationship, with the surgeon seated at a work-console, manipulating the master system and visualizing the operation on a video screen. Although enormous strides have been made to advance current technology to the point of clinical use, limitations still exist. A lack of haptic feedback to the surgeon and the inability of the surgeon to be stationed at the operating table are the most notable examples. The future of robotic surgery sees a marked increase in the visualization technologies used in the operating room, as well as in the robots' abilities to convey haptic feedback to the surgeon. This will allow unparalleled sensation for the surgeon and almost eliminate inadvertent tissue contact and injury. A novel design for a user interface will allow the surgeon to have access to the patient bedside, remaining sterile throughout the procedure, employ a head-mounted three-dimensional visualization system, and allow the most intuitive master manipulation of the slave robot to date.

Image-guided feedback for ophthalmic microsurgery using multimodal intraoperative swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography

NASA Astrophysics Data System (ADS)

Li, Jianwei D.; Malone, Joseph D.; El-Haddad, Mohamed T.; Arquitola, Amber M.; Joos, Karen M.; Patel, Shriji N.; Tao, Yuankai K.

2017-02-01

Surgical interventions for ocular diseases involve manipulations of semi-transparent structures in the eye, but limited visualization of these tissue layers remains a critical barrier to developing novel surgical techniques and improving clinical outcomes. We addressed limitations in image-guided ophthalmic microsurgery by using microscope-integrated multimodal intraoperative swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography (iSS-SESLO-OCT). We previously demonstrated in vivo human ophthalmic imaging using SS-SESLO-OCT, which enabled simultaneous acquisition of en face SESLO images with every OCT cross-section. Here, we integrated our new 400 kHz iSS-SESLO-OCT, which used a buffered Axsun 1060 nm swept-source, with a surgical microscope and TrueVision stereoscopic viewing system to provide image-based feedback. In vivo human imaging performance was demonstrated on a healthy volunteer, and simulated surgical maneuvers were performed in ex vivo porcine eyes. Denselysampled static volumes and volumes subsampled at 10 volumes-per-second were used to visualize tissue deformations and surgical dynamics during corneal sweeps, compressions, and dissections, and retinal sweeps, compressions, and elevations. En face SESLO images enabled orientation and co-registration with the widefield surgical microscope view while OCT imaging enabled depth-resolved visualization of surgical instrument positions relative to anatomic structures-of-interest. TrueVision heads-up display allowed for side-by-side viewing of the surgical field with SESLO and OCT previews for real-time feedback, and we demonstrated novel integrated segmentation overlays for augmented-reality surgical guidance. Integration of these complementary imaging modalities may benefit surgical outcomes by enabling real-time intraoperative visualization of surgical plans, instrument positions, tissue deformations, and image-based surrogate biomarkers correlated with completion of surgical goals.

ERPs associated with monitoring and evaluation of monetary reward and punishment in children with ADHD.

PubMed

van Meel, Catharina S; Heslenfeld, Dirk J; Oosterlaan, Jaap; Luman, Marjolein; Sergeant, Joseph A

2011-09-01

Several models of attention-deficit hyperactivity disorder (ADHD) propose abnormalities in the response to behavioural contingencies. Using event-related potentials (ERPs), the present study investigated the monitoring and subsequent evaluation of performance feedback resulting in either reward or punishment in children with ADHD (N = 18) and normal controls (N = 18) aged 8 to 12 years. Children performed a time production task, in which visual performance feedback was given after each response. To manipulate its motivational salience, feedback was coupled with monetary gains, losses or no incentives. Performance feedback signalling omitted gains as well as omitted losses evoked a feedback-related negativity (FRN) in control children. The FRN, however, was entirely absent in children with ADHD in all conditions. Moreover, while losses elicited enhanced amplitudes of the late positive potential (LPP) in controls, omitted rewards had this effect in ADHD. The lack of modulation of the FRN by contingencies in ADHD suggests deficient detection of environmental cues as a function of their motivational significance. LPP findings suggest diminished response to punishment, but oversensitivity to the loss of desired rewards. These findings suggest that children with ADHD have problems assigning relative motivational significance to outcomes of their actions. © 2011 The Authors. Journal of Child Psychology and Psychiatry © 2011 Association for Child and Adolescent Mental Health.

Investigating the role of feedback and motivation in clinical reaction time assessment.

PubMed

Eckner, James T; Chandran, Srikrishna; Richardson, James K

2011-12-01

To investigate the influence of performance feedback and motivation during 2 tests of simple visuomotor reaction time (RT). Cross-sectional, observational study. Outpatient academic physiatry clinic. Thirty-one healthy adults (mean [SD], 54 ± 15 years). Participants completed a clinical test of RT (RT(clin)) and a computerized test of RT with and without performance feedback (RT(compFB) and RT(compNoFB), respectively) in randomly assigned order. They then ranked their degree of motivation during each test. RT(clin) measured the time required to catch a suspended vertical shaft by hand closure after release of the shaft by the examiner. RT(compFB) and RT(compNoFB) both measured the time required to press a computer key in response to a visual cue displayed on a computer monitor. Performance feedback (visual display of the previous trial and summary results) was provided for RT(compFB), but not for RT(compNoFB). Means and standard deviations of RT(clin), RT(compFB), and RT(compNoFB) and participants' self-reported motivation on a 5-point Likert scale for each test. There were significant differences in both the means and standard deviations of RT(clin), RT(compFB), and RT(compNoFB) (F(2,60) = 81.66, P < .0001; F(2,60) = 32.46, P < .0001, respectively), with RT(clin) being both the fastest and least variable of the RT measurements. RT(clin) was more strongly correlated with RT(compFB) (r = 0.449, P = .0011) than with RT(compNoFB) (r = 0.314, P = .086). The participants reported similar levels of motivation between RT(clin) and RT(compFB), both of which were reported to be more motivating than RT(compNoFB). The stronger correlation between RT(clin) and RT(compFB) as well as the higher reported motivation during RT(clin) and RT(compFB) testing suggest that performance feedback is a positive motivating factor that is inherent to RT(clin) testing. RT(clin) is a simple, inexpensive technique for measuring RT and appears to be an intrinsically motivating task. This motivation may promote faster, more consistent RT performance compared with currently available computerized programs, which do not typically provide performance feedback. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Mastoidectomy simulation with combined visual and haptic feedback.

PubMed

Agus, Marco; Giachetti, Andrea; Gobbetti, Enrico; Zanetti, Gianluigi; Zorcolo, Antonio; John, Nigel W; Stone, Robert J

2002-01-01

Mastoidectomy is one of the most common surgical procedures relating to the petrous bone. In this paper we describe our preliminary results in the realization of a virtual reality mastoidectomy simulator. Our system is designed to work on patient-specific volumetric object models directly derived from 3D CT and MRI images. The paper summarizes the detailed task analysis performed in order to define the system requirements, introduces the architecture of the prototype simulator, and discusses the initial feedback received from selected end users.

Brain negativity as an indicator of predictive error processing: the contribution of visual action effect monitoring.

PubMed

Joch, Michael; Hegele, Mathias; Maurer, Heiko; Müller, Hermann; Maurer, Lisa Katharina

2017-07-01

The error (related) negativity (Ne/ERN) is an event-related potential in the electroencephalogram (EEG) correlating with error processing. Its conditions of appearance before terminal external error information suggest that the Ne/ERN is indicative of predictive processes in the evaluation of errors. The aim of the present study was to specifically examine the Ne/ERN in a complex motor task and to particularly rule out other explaining sources of the Ne/ERN aside from error prediction processes. To this end, we focused on the dependency of the Ne/ERN on visual monitoring about the action outcome after movement termination but before result feedback (action effect monitoring). Participants performed a semi-virtual throwing task by using a manipulandum to throw a virtual ball displayed on a computer screen to hit a target object. Visual feedback about the ball flying to the target was masked to prevent action effect monitoring. Participants received a static feedback about the action outcome (850 ms) after each trial. We found a significant negative deflection in the average EEG curves of the error trials peaking at ~250 ms after ball release, i.e., before error feedback. Furthermore, this Ne/ERN signal did not depend on visual ball-flight monitoring after release. We conclude that the Ne/ERN has the potential to indicate error prediction in motor tasks and that it exists even in the absence of action effect monitoring. NEW & NOTEWORTHY In this study, we are separating different kinds of possible contributors to an electroencephalogram (EEG) error correlate (Ne/ERN) in a throwing task. We tested the influence of action effect monitoring on the Ne/ERN amplitude in the EEG. We used a task that allows us to restrict movement correction and action effect monitoring and to control the onset of result feedback. We ascribe the Ne/ERN to predictive error processing where a conscious feeling of failure is not a prerequisite. Copyright © 2017 the American Physiological Society.

Visual crowding illustrates the inadequacy of local vs. global and feedforward vs. feedback distinctions in modeling visual perception

PubMed Central

Clarke, Aaron M.; Herzog, Michael H.; Francis, Gregory

2014-01-01

Experimentalists tend to classify models of visual perception as being either local or global, and involving either feedforward or feedback processing. We argue that these distinctions are not as helpful as they might appear, and we illustrate these issues by analyzing models of visual crowding as an example. Recent studies have argued that crowding cannot be explained by purely local processing, but that instead, global factors such as perceptual grouping are crucial. Theories of perceptual grouping, in turn, often invoke feedback connections as a way to account for their global properties. We examined three types of crowding models that are representative of global processing models, and two of which employ feedback processing: a model based on Fourier filtering, a feedback neural network, and a specific feedback neural architecture that explicitly models perceptual grouping. Simulations demonstrate that crucial empirical findings are not accounted for by any of the models. We conclude that empirical investigations that reject a local or feedforward architecture offer almost no constraints for model construction, as there are an uncountable number of global and feedback systems. We propose that the identification of a system as being local or global and feedforward or feedback is less important than the identification of a system's computational details. Only the latter information can provide constraints on model development and promote quantitative explanations of complex phenomena. PMID:25374554

The effect of modifying response and performance feedback parameters on the CNV in humans

NASA Technical Reports Server (NTRS)

Otto, D. A.; Leifer, L. J.

1972-01-01

The effect on the CNV of sustained and delayed motor response with the dominant and nondominant hand in the presence and absence of visual performance feedback, was studied in 15 male adults. Monopolar scalp recordings were obtained at Fz, Cz, Pz, and bilaterally over the motor hand area. Results indicated that the magnitude of the CNV was greater in the delayed than sustained response task, greater in the presence than absence of feedback, and greater over the motor hand area contralateral to movement. Frontal CNV habituated in the sustained, but not the delayed response task, suggested that frontal negative variations in the former case signify an orienting response to novelty or uncertainty. The absence of habituation in the delay condition was interpreted in terms of the motor inhibitory function of frontal association cortex. Performance feedback appeared to enhance CNV indirectly by increasing the motivation of subjects. A multiprocess conception of CNV was proposed in which vortex-negative slow potentials reflect a multiplicity of psychophysiological processes occurring at a variety of cortical and subcortical locations in the brain preparatory to a motor or mental action.

Active versus Passive Training of a Complex Bimanual Task: Is Prescriptive Proprioceptive Information Sufficient for Inducing Motor Learning?

PubMed Central

Beets, Iseult A. M.; Macé, Marc; Meesen, Raf L. J.; Cuypers, Koen; Levin, Oron; Swinnen, Stephan P.

2012-01-01

Perceptual processes play an important role in motor learning. While it is evident that visual information greatly contributes to learning new movements, much less is known about provision of prescriptive proprioceptive information. Here, we investigated whether passive (proprioceptively-based) movement training was comparable to active training for learning a new bimanual task. Three groups practiced a bimanual coordination pattern with a 1∶2 frequency ratio and a 90° phase offset between both wrists with Lissajous feedback over the course of four days: 1) passive training; 2) active training; 3) no training (control). Retention findings revealed that passive as compared to active training resulted in equally successful acquisition of the frequency ratio but active training was more effective for acquisition of the new relative phasing between the limbs in the presence of augmented visual feedback. However, when this feedback was removed, performance of the new relative phase deteriorated in both groups whereas the frequency ratio was better preserved. The superiority of active over passive training in the presence of augmented feedback is hypothesized to result from active involvement in processes of error detection/correction and planning. PMID:22666379

Visual Feedback Dominates the Sense of Agency for Brain-Machine Actions

PubMed Central

Evans, Nathan; Gale, Steven; Schurger, Aaron; Blanke, Olaf

2015-01-01

Recent advances in neuroscience and engineering have led to the development of technologies that permit the control of external devices through real-time decoding of brain activity (brain-machine interfaces; BMI). Though the feeling of controlling bodily movements (sense of agency; SOA) has been well studied and a number of well-defined sensorimotor and cognitive mechanisms have been put forth, very little is known about the SOA for BMI-actions. Using an on-line BMI, and verifying that our subjects achieved a reasonable level of control, we sought to describe the SOA for BMI-mediated actions. Our results demonstrate that discrepancies between decoded neural activity and its resultant real-time sensory feedback are associated with a decrease in the SOA, similar to SOA mechanisms proposed for bodily actions. However, if the feedback discrepancy serves to correct a poorly controlled BMI-action, then the SOA can be high and can increase with increasing discrepancy, demonstrating the dominance of visual feedback on the SOA. Taken together, our results suggest that bodily and BMI-actions rely on common mechanisms of sensorimotor integration for agency judgments, but that visual feedback dominates the SOA in the absence of overt bodily movements or proprioceptive feedback, however erroneous the visual feedback may be. PMID:26066840

The effect of visual-motion time-delays on pilot performance in a simulated pursuit tracking task

NASA Technical Reports Server (NTRS)

Miller, G. K., Jr.; Riley, D. R.

1977-01-01

An experimental study was made to determine the effect on pilot performance of time delays in the visual and motion feedback loops of a simulated pursuit tracking task. Three major interrelated factors were identified: task difficulty either in the form of airplane handling qualities or target frequency, the amount and type of motion cues, and time delay itself. In general, the greater the task difficulty, the smaller the time delay that could exist without degrading pilot performance. Conversely, the greater the motion fidelity, the greater the time delay that could be tolerated. The effect of motion was, however, pilot dependent.

Visuomotor adaptation needs a validation of prediction error by feedback error

PubMed Central

Gaveau, Valérie; Prablanc, Claude; Laurent, Damien; Rossetti, Yves; Priot, Anne-Emmanuelle

2014-01-01

The processes underlying short-term plasticity induced by visuomotor adaptation to a shifted visual field are still debated. Two main sources of error can induce motor adaptation: reaching feedback errors, which correspond to visually perceived discrepancies between hand and target positions, and errors between predicted and actual visual reafferences of the moving hand. These two sources of error are closely intertwined and difficult to disentangle, as both the target and the reaching limb are simultaneously visible. Accordingly, the goal of the present study was to clarify the relative contributions of these two types of errors during a pointing task under prism-displaced vision. In “terminal feedback error” condition, viewing of their hand by subjects was allowed only at movement end, simultaneously with viewing of the target. In “movement prediction error” condition, viewing of the hand was limited to movement duration, in the absence of any visual target, and error signals arose solely from comparisons between predicted and actual reafferences of the hand. In order to prevent intentional corrections of errors, a subthreshold, progressive stepwise increase in prism deviation was used, so that subjects remained unaware of the visual deviation applied in both conditions. An adaptive aftereffect was observed in the “terminal feedback error” condition only. As far as subjects remained unaware of the optical deviation and self-assigned pointing errors, prediction error alone was insufficient to induce adaptation. These results indicate a critical role of hand-to-target feedback error signals in visuomotor adaptation; consistent with recent neurophysiological findings, they suggest that a combination of feedback and prediction error signals is necessary for eliciting aftereffects. They also suggest that feedback error updates the prediction of reafferences when a visual perturbation is introduced gradually and cognitive factors are eliminated or strongly attenuated. PMID:25408644

Balance rehabilitation: promoting the role of virtual reality in patients with diabetic peripheral neuropathy.

PubMed

Grewal, Gurtej S; Sayeed, Rashad; Schwenk, Michael; Bharara, Manish; Menzies, Robert; Talal, Talal K; Armstrong, David G; Najafi, Bijan

2013-01-01

Individuals with diabetic peripheral neuropathy frequently experience concomitant impaired proprioception and postural instability. Conventional exercise training has been demonstrated to be effective in improving balance but does not incorporate visual feedback targeting joint perception, which is an integral mechanism that helps compensate for impaired proprioception in diabetic peripheral neuropathy. This prospective cohort study recruited 29 participants (mean ± SD: age, 57 ± 10 years; body mass index [calculated as weight in kilograms divided by height in meters squared], 26.9 ± 3.1). Participants satisfying the inclusion criteria performed predefined ankle exercises through reaching tasks, with visual feedback from the ankle joint projected on a screen. Ankle motion in the mediolateral and anteroposterior directions was captured using wearable sensors attached to the participant's shank. Improvements in postural stability were quantified by measuring center of mass sway area and the reciprocal compensatory index before and after training using validated body-worn sensor technology. Findings revealed a significant reduction in center of mass sway after training (mean, 22%; P = .02). A higher postural stability deficit (high body sway) at baseline was associated with higher training gains in postural balance (reduction in center of mass sway) (r = -0.52, P < .05). In addition, significant improvement was observed in postural coordination between the ankle and hip joints (mean, 10.4%; P = .04). The present research implemented a novel balance rehabilitation strategy based on virtual reality technology. The method included wearable sensors and an interactive user interface for real-time visual feedback based on ankle joint motion, similar to a video gaming environment, for compensating impaired joint proprioception. These findings support that visual feedback generated from the ankle joint coupled with motor learning may be effective in improving postural stability in patients with diabetic peripheral neuropathy.

Children with Heavy Prenatal Alcohol Exposure Experience Reduced Control of Isotonic Force

PubMed Central

Nguyen, Tanya T.; Levy, Susan S.; Riley, Edward P.; Thomas, Jennifer D.; Simmons, Roger W.

2013-01-01

Background Heavy prenatal alcohol exposure can result in diverse and extensive damage to the central nervous system, including the cerebellum, basal ganglia, and cerebral cortex. Given that these brain regions are involved in the generation and maintenance of motor force, we predicted that prenatal alcohol exposure would adversely affect this parameter of motor control. We previously reported that children with gestational alcohol exposure experience significant deficits in regulating isometric (i.e., constant) force. The purpose of the present study was to determine if these children exhibit similar deficits when producing isotonic (i.e., graded) force. Methods Children with heavy prenatal alcohol exposure and typically developing children completed a series of isotonic force contractions by exerting force on a load cell to match a criterion target force displayed on a computer monitor. Two levels of target force (5% or 20% of maximum voluntary force) were investigated in combination with varying levels of visual feedback. Results Compared to controls, children with heavy prenatal alcohol exposure generated isotonic force signals that were less accurate, more variable, and less complex in the time domain compared to control children. Specifically, interactions were found between group and visual feedback for response accuracy and signal complexity, suggesting that these children have greater difficulty altering their motor output when visual feedback is low. Conclusions These data suggest that prenatal alcohol exposure produces deficits in regulating isotonic force, which presumably result from alcohol-related damage to developing brain regions involved in motor control. These children will most likely experience difficulty performing basic motor skills and daily functional skills that require coordination of finely graded force. Therapeutic strategies designed to increase feedback and, consequently, facilitate visual-motor integration could improve isotonic force production in these children. PMID:22834891

Real-time vision, tactile cues, and visual form agnosia: removing haptic feedback from a “natural” grasping task induces pantomime-like grasps

PubMed Central

Whitwell, Robert L.; Ganel, Tzvi; Byrne, Caitlin M.; Goodale, Melvyn A.

2015-01-01

Investigators study the kinematics of grasping movements (prehension) under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. “Natural” prehensile acts are directed at the goal object and are executed using real-time vision. Typically, they also entail the use of tactile, proprioceptive, and kinesthetic sources of haptic feedback about the object (“haptics-based object information”) once contact with the object has been made. Natural and simulated (pantomimed) forms of prehension are thought to recruit different cortical structures: patient DF, who has visual form agnosia following bilateral damage to her temporal-occipital cortex, loses her ability to scale her grasp aperture to the size of targets (“grip scaling”) when her prehensile movements are based on a memory of a target previewed 2 s before the cue to respond or when her grasps are directed towards a visible virtual target but she is denied haptics-based information about the target. In the first of two experiments, we show that when DF performs real-time pantomimed grasps towards a 7.5 cm displaced imagined copy of a visible object such that her fingers make contact with the surface of the table, her grip scaling is in fact quite normal. This finding suggests that real-time vision and terminal tactile feedback are sufficient to preserve DF’s grip scaling slopes. In the second experiment, we examined an “unnatural” grasping task variant in which a tangible target (along with any proxy such as the surface of the table) is denied (i.e., no terminal tactile feedback). To do this, we used a mirror-apparatus to present virtual targets with and without a spatially coincident copy for the participants to grasp. We compared the grasp kinematics from trials with and without terminal tactile feedback to a real-time-pantomimed grasping task (one without tactile feedback) in which participants visualized a copy of the visible target as instructed in our laboratory in the past. Compared to natural grasps, removing tactile feedback increased RT, slowed the velocity of the reach, reduced in-flight grip aperture, increased the slopes relating grip aperture to target width, and reduced the final grip aperture (FGA). All of these effects were also observed in the real time-pantomime grasping task. These effects seem to be independent of those that arise from using the mirror in general as we also compared grasps directed towards virtual targets to those directed at real ones viewed directly through a pane of glass. These comparisons showed that the grasps directed at virtual targets increased grip aperture, slowed the velocity of the reach, and reduced the slopes relating grip aperture to the widths of the target. Thus, using the mirror has real consequences on grasp kinematics, reflecting the importance of task-relevant sources of online visual information for the programming and updating of natural prehensile movements. Taken together, these results provide compelling support for the view that removing terminal tactile feedback, even when the grasps are target-directed, induces a switch from real-time visual control towards one that depends more on visual perception and cognitive supervision. Providing terminal tactile feedback and real-time visual information can evidently keep the dorsal visuomotor system operating normally for prehensile acts. PMID:25999834

Real-time vision, tactile cues, and visual form agnosia: removing haptic feedback from a "natural" grasping task induces pantomime-like grasps.

PubMed

Whitwell, Robert L; Ganel, Tzvi; Byrne, Caitlin M; Goodale, Melvyn A

2015-01-01

Investigators study the kinematics of grasping movements (prehension) under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. "Natural" prehensile acts are directed at the goal object and are executed using real-time vision. Typically, they also entail the use of tactile, proprioceptive, and kinesthetic sources of haptic feedback about the object ("haptics-based object information") once contact with the object has been made. Natural and simulated (pantomimed) forms of prehension are thought to recruit different cortical structures: patient DF, who has visual form agnosia following bilateral damage to her temporal-occipital cortex, loses her ability to scale her grasp aperture to the size of targets ("grip scaling") when her prehensile movements are based on a memory of a target previewed 2 s before the cue to respond or when her grasps are directed towards a visible virtual target but she is denied haptics-based information about the target. In the first of two experiments, we show that when DF performs real-time pantomimed grasps towards a 7.5 cm displaced imagined copy of a visible object such that her fingers make contact with the surface of the table, her grip scaling is in fact quite normal. This finding suggests that real-time vision and terminal tactile feedback are sufficient to preserve DF's grip scaling slopes. In the second experiment, we examined an "unnatural" grasping task variant in which a tangible target (along with any proxy such as the surface of the table) is denied (i.e., no terminal tactile feedback). To do this, we used a mirror-apparatus to present virtual targets with and without a spatially coincident copy for the participants to grasp. We compared the grasp kinematics from trials with and without terminal tactile feedback to a real-time-pantomimed grasping task (one without tactile feedback) in which participants visualized a copy of the visible target as instructed in our laboratory in the past. Compared to natural grasps, removing tactile feedback increased RT, slowed the velocity of the reach, reduced in-flight grip aperture, increased the slopes relating grip aperture to target width, and reduced the final grip aperture (FGA). All of these effects were also observed in the real time-pantomime grasping task. These effects seem to be independent of those that arise from using the mirror in general as we also compared grasps directed towards virtual targets to those directed at real ones viewed directly through a pane of glass. These comparisons showed that the grasps directed at virtual targets increased grip aperture, slowed the velocity of the reach, and reduced the slopes relating grip aperture to the widths of the target. Thus, using the mirror has real consequences on grasp kinematics, reflecting the importance of task-relevant sources of online visual information for the programming and updating of natural prehensile movements. Taken together, these results provide compelling support for the view that removing terminal tactile feedback, even when the grasps are target-directed, induces a switch from real-time visual control towards one that depends more on visual perception and cognitive supervision. Providing terminal tactile feedback and real-time visual information can evidently keep the dorsal visuomotor system operating normally for prehensile acts.

Examining the effect of state anxiety on compensatory and strategic adjustments in the planning of goal-directed aiming.

PubMed

Roberts, James W; Wilson, Mark R; Skultety, Jessica K; Lyons, James L

2018-04-01

The anxiety-perceptual-motor performance relationship may be enriched by investigations involving discrete manual responses due to the definitive demarcation of planning and control processes, which comprise the early and late portions of movement, respectively. To further examine the explanatory power of self-focus and distraction theories, we explored the potential of anxiety causing changes to movement planning that accommodate for anticipated negative effects in online control. As a result, we posed two hypotheses where anxiety causes performers to initially undershoot the target and enable more time to use visual feedback ("play-it-safe"), or fire a ballistic reach to cover a greater distance without later undertaking online control ("go-for-it"). Participants were tasked with an upper-limb movement to a single target under counter-balanced instructions to execute fast and accurate responses (low/normal anxiety) with non-contingent negative performance feedback (high anxiety). The results indicated that the previously identified negative impact of anxiety in online control was replicated. While anxiety caused a longer displacement to reach peak velocity and greater tendency to overshoot the target, there appeared to be no shift in the attempts to utilise online visual feedback. Thus, the tendency to initially overshoot may manifest from an inefficient auxiliary procedure that manages to uphold overall movement time and response accuracy. Copyright © 2018 Elsevier B.V. All rights reserved.

Multitask neurovision processor with extensive feedback and feedforward connections

NASA Astrophysics Data System (ADS)

Gupta, Madan M.; Knopf, George K.

1991-11-01

A multi-task neuro-vision parameter which performs a variety of information processing operations associated with the early stages of biological vision is presented. The network architecture of this neuro-vision processor, called the positive-negative (PN) neural processor, is loosely based on the neural activity fields exhibited by thalamic and cortical nervous tissue layers. The computational operation performed by the processor arises from the strength of the recurrent feedback among the numerous positive and negative neural computing units. By adjusting the feedback connections it is possible to generate diverse dynamic behavior that may be used for short-term visual memory (STVM), spatio-temporal filtering (STF), and pulse frequency modulation (PFM). The information attributes that are to be processes may be regulated by modifying the feedforward connections from the signal space to the neural processor.

Computer-enhanced visual learning method: a paradigm to teach and document surgical skills.

PubMed

Maizels, Max; Mickelson, Jennie; Yerkes, Elizabeth; Maizels, Evelyn; Stork, Rachel; Young, Christine; Corcoran, Julia; Holl, Jane; Kaplan, William E

2009-09-01

Changes in health care are stimulating residency training programs to develop new methods for teaching surgical skills. We developed Computer-Enhanced Visual Learning (CEVL) as an innovative Internet-based learning and assessment tool. The CEVL method uses the educational procedures of deliberate practice and performance to teach and learn surgery in a stylized manner. CEVL is a learning and assessment tool that can provide students and educators with quantitative feedback on learning a specific surgical procedure. Methods involved examine quantitative data of improvement in surgical skills. Herein, we qualitatively describe the method and show how program directors (PDs) may implement this technique in their residencies. CEVL allows an operation to be broken down into teachable components. The process relies on feedback and remediation to improve performance, with a focus on learning that is applicable to the next case being performed. CEVL has been shown to be effective for teaching pediatric orchiopexy and is being adapted to additional adult and pediatric procedures and to office examination skills. The CEVL method is available to other residency training programs.

Computer-Enhanced Visual Learning Method: A Paradigm to Teach and Document Surgical Skills

PubMed Central

Maizels, Max; Mickelson, Jennie; Yerkes, Elizabeth; Maizels, Evelyn; Stork, Rachel; Young, Christine; Corcoran, Julia; Holl, Jane; Kaplan, William E.

2009-01-01

Innovation Changes in health care are stimulating residency training programs to develop new methods for teaching surgical skills. We developed Computer-Enhanced Visual Learning (CEVL) as an innovative Internet-based learning and assessment tool. The CEVL method uses the educational procedures of deliberate practice and performance to teach and learn surgery in a stylized manner. Aim of Innovation CEVL is a learning and assessment tool that can provide students and educators with quantitative feedback on learning a specific surgical procedure. Methods involved examine quantitative data of improvement in surgical skills. Herein, we qualitatively describe the method and show how program directors (PDs) may implement this technique in their residencies. Results CEVL allows an operation to be broken down into teachable components. The process relies on feedback and remediation to improve performance, with a focus on learning that is applicable to the next case being performed. CEVL has been shown to be effective for teaching pediatric orchiopexy and is being adapted to additional adult and pediatric procedures and to office examination skills. The CEVL method is available to other residency training programs. PMID:21975716

Shaping with Visual Feedback and Token Reinforcement: Effects on Voice Volume Changes in Mentally Retarded Adults.

ERIC Educational Resources Information Center

Bieber, Carrie; Gurski, John C.

In an attempt to confirm earlier results with a group of mentally retarded females, 12 mentally retarded institutionalized adults (8 male, 4 female) were trained to either reduce (Loud group) or increase (Soft group) their voice volumes with a combination of visual feedback and token reinforcement. The feedback unit provided a binary light on-off…

Effect of Training Japanese L1 Speakers in the Production of American English /r/ Using Spectrographic Visual Feedback

ERIC Educational Resources Information Center

Patten, Iomi; Edmonds, Lisa A.

2015-01-01

The present study examines the effects of training native Japanese speakers in the production of American /r/ using spectrographic visual feedback. Within a modified single-subject design, two native Japanese participants produced single words containing /r/ in a variety of positions while viewing live spectrographic feedback with the aim of…

Isolating Visual and Proprioceptive Components of Motor Sequence Learning in ASD.

PubMed

Sharer, Elizabeth A; Mostofsky, Stewart H; Pascual-Leone, Alvaro; Oberman, Lindsay M

2016-05-01

In addition to defining impairments in social communication skills, individuals with autism spectrum disorder (ASD) also show impairments in more basic sensory and motor skills. Development of new skills involves integrating information from multiple sensory modalities. This input is then used to form internal models of action that can be accessed when both performing skilled movements, as well as understanding those actions performed by others. Learning skilled gestures is particularly reliant on integration of visual and proprioceptive input. We used a modified serial reaction time task (SRTT) to decompose proprioceptive and visual components and examine whether patterns of implicit motor skill learning differ in ASD participants as compared with healthy controls. While both groups learned the implicit motor sequence during training, healthy controls showed robust generalization whereas ASD participants demonstrated little generalization when visual input was constant. In contrast, no group differences in generalization were observed when proprioceptive input was constant, with both groups showing limited degrees of generalization. The findings suggest, when learning a motor sequence, individuals with ASD tend to rely less on visual feedback than do healthy controls. Visuomotor representations are considered to underlie imitative learning and action understanding and are thereby crucial to social skill and cognitive development. Thus, anomalous patterns of implicit motor learning, with a tendency to discount visual feedback, may be an important contributor in core social communication deficits that characterize ASD. Autism Res 2016, 9: 563-569. © 2015 International Society for Autism Research, Wiley Periodicals, Inc. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

EEG Theta Dynamics within Frontal and Parietal Cortices for Error Processing during Reaching Movements in a Prism Adaptation Study Altering Visuo-Motor Predictive Planning

PubMed Central

Bonfiglio, Luca; Minichilli, Fabrizio; Cantore, Nicoletta; Carboncini, Maria Chiara; Piccotti, Emily; Rossi, Bruno

2016-01-01

Modulation of frontal midline theta (fmθ) is observed during error commission, but little is known about the role of theta oscillations in correcting motor behaviours. We investigate EEG activity of healthy partipants executing a reaching task under variable degrees of prism-induced visuo-motor distortion and visual occlusion of the initial arm trajectory. This task introduces directional errors of different magnitudes. The discrepancy between predicted and actual movement directions (i.e. the error), at the time when visual feedback (hand appearance) became available, elicits a signal that triggers on-line movement correction. Analysis were performed on 25 EEG channels. For each participant, the median value of the angular error of all reaching trials was used to partition the EEG epochs into high- and low-error conditions. We computed event-related spectral perturbations (ERSP) time-locked either to visual feedback or to the onset of movement correction. ERSP time-locked to the onset of visual feedback showed that fmθ increased in the high- but not in the low-error condition with an approximate time lag of 200 ms. Moreover, when single epochs were sorted by the degree of motor error, fmθ started to increase when a certain level of error was exceeded and, then, scaled with error magnitude. When ERSP were time-locked to the onset of movement correction, the fmθ increase anticipated this event with an approximate time lead of 50 ms. During successive trials, an error reduction was observed which was associated with indices of adaptations (i.e., aftereffects) suggesting the need to explore if theta oscillations may facilitate learning. To our knowledge this is the first study where the EEG signal recorded during reaching movements was time-locked to the onset of the error visual feedback. This allowed us to conclude that theta oscillations putatively generated by anterior cingulate cortex activation are implicated in error processing in semi-naturalistic motor behaviours. PMID:26963919

EEG Theta Dynamics within Frontal and Parietal Cortices for Error Processing during Reaching Movements in a Prism Adaptation Study Altering Visuo-Motor Predictive Planning.

PubMed

Arrighi, Pieranna; Bonfiglio, Luca; Minichilli, Fabrizio; Cantore, Nicoletta; Carboncini, Maria Chiara; Piccotti, Emily; Rossi, Bruno; Andre, Paolo

2016-01-01

Modulation of frontal midline theta (fmθ) is observed during error commission, but little is known about the role of theta oscillations in correcting motor behaviours. We investigate EEG activity of healthy partipants executing a reaching task under variable degrees of prism-induced visuo-motor distortion and visual occlusion of the initial arm trajectory. This task introduces directional errors of different magnitudes. The discrepancy between predicted and actual movement directions (i.e. the error), at the time when visual feedback (hand appearance) became available, elicits a signal that triggers on-line movement correction. Analysis were performed on 25 EEG channels. For each participant, the median value of the angular error of all reaching trials was used to partition the EEG epochs into high- and low-error conditions. We computed event-related spectral perturbations (ERSP) time-locked either to visual feedback or to the onset of movement correction. ERSP time-locked to the onset of visual feedback showed that fmθ increased in the high- but not in the low-error condition with an approximate time lag of 200 ms. Moreover, when single epochs were sorted by the degree of motor error, fmθ started to increase when a certain level of error was exceeded and, then, scaled with error magnitude. When ERSP were time-locked to the onset of movement correction, the fmθ increase anticipated this event with an approximate time lead of 50 ms. During successive trials, an error reduction was observed which was associated with indices of adaptations (i.e., aftereffects) suggesting the need to explore if theta oscillations may facilitate learning. To our knowledge this is the first study where the EEG signal recorded during reaching movements was time-locked to the onset of the error visual feedback. This allowed us to conclude that theta oscillations putatively generated by anterior cingulate cortex activation are implicated in error processing in semi-naturalistic motor behaviours.

A computer simulation experiment of supervisory control of remote manipulation. M.S. Thesis

NASA Technical Reports Server (NTRS)

Mccandlish, S. G.

1966-01-01

A computer simulation of a remote manipulation task and a rate-controlled manipulator is described. Some low-level automatic decision making ability which could be used at the operator's discretion to augment his direct continuous control was built into the manipulator. Experiments were made on the effect of transmission delay, dynamic lag, and intermittent vision on human manipulative ability. Delay does not make remote manipulation impossible. Intermittent visual feedback, and the absence of rate information in the display presented to the operator do not seem to impair the operator's performance. A small-capacity visual feedback channel may be sufficient for remote manipulation tasks, or one channel might be time-shared between several operators. In other experiments the operator called in sequence various on-site automatic control programs of the machine, and thereby acted as a supervisor. The supervisory mode of operation has some advantages when the task to be performed is difficult for a human controlling directly.

Mirror Visual Feedback Induces Lower Neuromuscular Activity in Children with Spastic Hemiparetic Cerebral Palsy

ERIC Educational Resources Information Center

Feltham, Max G.; Ledebt, Annick; Deconinck, Frederik J. A.; Savelsbergh, Geert J. P.

2010-01-01

The study examined the effects of mirror feedback information on neuromuscular activation during bimanual coordination in eight children with spastic hemiparetic cerebral palsy (SHCP) and a matched control group. The "mirror box" creates a visual illusion, which gives rise to a visual perception of a zero lag, symmetric movement between the two…

A real-time articulatory visual feedback approach with target presentation for second language pronunciation learning.

PubMed

Suemitsu, Atsuo; Dang, Jianwu; Ito, Takayuki; Tiede, Mark

2015-10-01

Articulatory information can support learning or remediating pronunciation of a second language (L2). This paper describes an electromagnetic articulometer-based visual-feedback approach using an articulatory target presented in real-time to facilitate L2 pronunciation learning. This approach trains learners to adjust articulatory positions to match targets for a L2 vowel estimated from productions of vowels that overlap in both L1 and L2. Training of Japanese learners for the American English vowel /æ/ that included visual training improved its pronunciation regardless of whether audio training was also included. Articulatory visual feedback is shown to be an effective method for facilitating L2 pronunciation learning.

Closed-loop control of grasping with a myoelectric hand prosthesis: which are the relevant feedback variables for force control?

PubMed

Ninu, Andrei; Dosen, Strahinja; Muceli, Silvia; Rattay, Frank; Dietl, Hans; Farina, Dario

2014-09-01

In closed-loop control of grasping by hand prostheses, the feedback information sent to the user is usually the actual controlled variable, i.e., the grasp force. Although this choice is intuitive and logical, the force production is only the last step in the process of grasping. Therefore, this study evaluated the performance in controlling grasp strength using a hand prosthesis operated through a complete grasping sequence while varying the feedback variables (e.g., closing velocity, grasping force), which were provided to the user visually or through vibrotactile stimulation. The experiments were conducted on 13 volunteers who controlled the Otto Bock Sensor Hand Speed prosthesis. Results showed that vibrotactile patterns were able to replace the visual feedback. Interestingly, the experiments demonstrated that direct force feedback was not essential for the control of grasping force. The subjects were indeed able to control the grip strength, predictively, by estimating the grasping force from the prosthesis velocity of closing. Therefore, grasping without explicit force feedback is not completely blind, contrary to what is usually assumed. In our study we analyzed grasping with a specific prosthetic device, but the outcomes are also applicable for other devices, with one or more degrees-of-freedom. The necessary condition is that the electromyography (EMG) signal directly and proportionally controls the velocity/grasp force of the hand, which is a common approach among EMG controlled prosthetic devices. The results provide important indications on the design of closed-loop EMG controlled prosthetic systems.

Adaptation to Laterally Displacing Prisms in Anisometropic Amblyopia.

PubMed

Sklar, Jaime C; Goltz, Herbert C; Gane, Luke; Wong, Agnes M F

2015-06-01

Using visual feedback to modify sensorimotor output in response to changes in the external environment is essential for daily function. Prism adaptation is a well-established experimental paradigm to quantify sensorimotor adaptation; that is, how the sensorimotor system adapts to an optically-altered visuospatial environment. Amblyopia is a neurodevelopmental disorder characterized by spatiotemporal deficits in vision that impacts manual and oculomotor function. This study explored the effects of anisometropic amblyopia on prism adaptation. Eight participants with anisometropic amblyopia and 11 visually-normal adults, all right-handed, were tested. Participants pointed to visual targets and were presented with feedback of hand position near the terminus of limb movement in three blocks: baseline, adaptation, and deadaptation. Adaptation was induced by viewing with binocular 11.4° (20 prism diopter [PD]) left-shifting prisms. All tasks were performed during binocular viewing. Participants with anisometropic amblyopia required significantly more trials (i.e., increased time constant) to adapt to prismatic optical displacement than visually-normal controls. During the rapid error correction phase of adaptation, people with anisometropic amblyopia also exhibited greater variance in motor output than visually-normal controls. Amblyopia impacts on the ability to adapt the sensorimotor system to an optically-displaced visual environment. The increased time constant and greater variance in motor output during the rapid error correction phase of adaptation may indicate deficits in processing of visual information as a result of degraded spatiotemporal vision in amblyopia.

Motion detection technology as a tool for cardiopulmonary resuscitation (CPR) quality training: a randomised crossover mannequin pilot study.

PubMed

Semeraro, Federico; Frisoli, Antonio; Loconsole, Claudio; Bannò, Filippo; Tammaro, Gaetano; Imbriaco, Guglielmo; Marchetti, Luca; Cerchiari, Erga L

2013-04-01

Outcome after cardiac arrest is dependent on the quality of chest compressions (CC). A great number of devices have been developed to provide guidance during CPR. The present study evaluates a new CPR feedback system (Mini-VREM: Mini-Virtual Reality Enhanced Mannequin) designed to improve CC during training. Mini-VREM system consists of a Kinect(®) (Microsoft, Redmond, WA, USA) motion sensing device and specifically developed software to provide audio-visual feedback. Mini-VREM was connected to a commercially available mannequin (Laerdal Medical, Stavanger, Norway). Eighty trainees (healthcare professionals and lay people) volunteered in this randomised crossover pilot study. All subjects performed a 2 min CC trial, 1h pause and a second 2 min CC trial. The first group (FB/NFB, n=40) performed CC with Mini-VREM feedback (FB) followed by CC without feedback (NFB). The second group (NFB/FB, n=40) performed vice versa. Primary endpoints: adequate compression (compression rate between 100 and 120 min(-1) and compression depth between 50 and 60mm); compressions rate within 100-120 min(-1); compressions depth within 50-60mm. When compared to the performance without feedback, with Mini-VREM feedback compressions were more adequate (FB 35.78% vs. NFB 7.27%, p<0.001) and more compressions achieved target rate (FB 72.04% vs. 31.42%, p<0.001) and target depth (FB 47.34% vs. 24.87%, p=0.002). The participants perceived the system to be easy to use with effective feedback. The Mini-VREM system was able to improve significantly the CC performance by healthcare professionals and by lay people in a simulated CA scenario, in terms of compression rate and depth. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Stimulus change as a factor in response maintenance with free food available.

PubMed Central

Osborne, S R; Shelby, M

1975-01-01

Rats bar pressed for food on a reinforcement schedule in which every response was reinforced, even though a dish of pellets was present. Initially, auditory and visual stimuli accompanied response-produced food presentation. With stimulus feedback as an added consequence of bar pressing, responding was maintained in the presence of free food; without stimulus feedback, responding decreased to a low level. Auditory feedback maintained slightly more responding than did visual feedback, and both together maintained more responding than did either separately. Almost no responding occurred when the only consequence of bar pressing was stimulus feedback. The data indicated conditioned and sensory reinforcement effects of response-produced stimulus feedback. PMID:1202121

Defective imitation of finger configurations in patients with damage in the right or left hemispheres: An integration disorder of visual and somatosensory information?

PubMed

Okita, Manabu; Yukihiro, Takashi; Miyamoto, Kenzo; Morioka, Shu; Kaba, Hideto

2017-04-01

To explore the mechanism underlying the imitation of finger gestures, we devised a simple imitation task in which the patients were instructed to replicate finger configurations in two conditions: one in which they could see their hand (visual feedback: VF) and one in which they could not see their hand (non-visual feedback: NVF). Patients with left brain damage (LBD) or right brain damage (RBD), respectively, were categorized into two groups based on their scores on the imitation task in the NVF condition: the impaired imitation groups (I-LBD and I-RBD) who failed two or more of the five patterns and the control groups (C-LBD and C-RBD) who made one or no errors. We also measured the movement-production times for imitation. The I-RBD group performed significantly worse than the C-RBD group even in the VF condition. In contrast, the I-LBD group was selectively impaired in the NVF condition. The I-LBD group performed the imitations at a significantly slower rate than the C-LBD group in both the VF and NVF conditions. These results suggest that impaired imitation in patients with LBD is partly due to an abnormal integration of visual and somatosensory information based on the task specificity of the NVF condition. Copyright © 2017 Elsevier Inc. All rights reserved.

ERD-based online brain-machine interfaces (BMI) in the context of neurorehabilitation: optimizing BMI learning and performance.

PubMed

Soekadar, Surjo R; Witkowski, Matthias; Mellinger, Jürgen; Ramos, Ander; Birbaumer, Niels; Cohen, Leonardo G

2011-10-01

Event-related desynchronization (ERD) of sensori-motor rhythms (SMR) can be used for online brain-machine interface (BMI) control, but yields challenges related to the stability of ERD and feedback strategy to optimize BMI learning.Here, we compared two approaches to this challenge in 20 right-handed healthy subjects (HS, five sessions each, S1-S5) and four stroke patients (SP, 15 sessions each, S1-S15). ERD was recorded from a 275-sensor MEG system. During daily training,motor imagery-induced ERD led to visual and proprioceptive feedback delivered through an orthotic device attached to the subjects' hand and fingers. Group A trained with a heterogeneous reference value (RV) for ERD detection with binary feedback and Group B with a homogenous RV and graded feedback (10 HS and 2 SP in each group). HS in Group B showed better BMI performance than Group A (p < 0.001) and improved BMI control from S1 to S5 (p = 0.012) while Group A did not. In spite of the small n, SP in Group B showed a trend for a higher BMI performance (p = 0.06) and learning was significantly better (p < 0.05). Using a homogeneous RV and graded feedback led to improved modulation of ipsilesional activity resulting in superior BMI learning relative to use of a heterogeneous RV and binary feedback.

Playing checkers: detection and eye hand coordination in simulated prosthetic vision

NASA Astrophysics Data System (ADS)

Dagnelie, Gislin; Walter, Matthias; Yang, Liancheng

2006-09-01

In order to assess the potential for visual inspection and eye hand coordination without tactile feedback under conditions that may be available to future retinal prosthesis wearers, we studied the ability of sighted individuals to act upon pixelized visual information at very low resolution, equivalent to 20/2400 visual acuity. Live images from a head-mounted camera were low-pass filtered and presented in a raster of 6 × 10 circular Gaussian dots. Subjects could either freely move their gaze across the raster (free-viewing condition) or the raster position was locked to the subject's gaze by means of video-based pupil tracking (gaze-locked condition). Four normally sighted and one severely visually impaired subject with moderate nystagmus participated in a series of four experiments. Subjects' task was to count 1 to 16 white fields randomly distributed across an otherwise black checkerboard (counting task) or to place a black checker on each of the white fields (placing task). We found that all subjects were capable of learning both tasks after varying amounts of practice, both in the free-viewing and in the gaze-locked conditions. Normally sighted subjects all reached very similar performance levels independent of the condition. The practiced performance level of the visually impaired subject in the free-viewing condition was indistinguishable from that of the normally sighted subjects, but required approximately twice the amount of time to place checkers in the gaze-locked condition; this difference is most likely attributable to this subject's nystagmus. Thus, if early retinal prosthesis wearers can achieve crude form vision, then on the basis of these results they too should be able to perform simple eye hand coordination tasks without tactile feedback.

Selective Activation of the Deep Layers of the Human Primary Visual Cortex by Top-Down Feedback.

PubMed

Kok, Peter; Bains, Lauren J; van Mourik, Tim; Norris, David G; de Lange, Floris P

2016-02-08

In addition to bottom-up input, the visual cortex receives large amounts of feedback from other cortical areas [1-3]. One compelling example of feedback activation of early visual neurons in the absence of bottom-up input occurs during the famous Kanizsa illusion, where a triangular shape is perceived, even in regions of the image where there is no bottom-up visual evidence for it. This illusion increases the firing activity of neurons in the primary visual cortex with a receptive field on the illusory contour [4]. Feedback signals are largely segregated from feedforward signals within each cortical area, with feedforward signals arriving in the middle layer, while top-down feedback avoids the middle layers and predominantly targets deep and superficial layers [1, 2, 5, 6]. Therefore, the feedback-mediated activity increase in V1 during the perception of illusory shapes should lead to a specific laminar activity profile that is distinct from the activity elicited by bottom-up stimulation. Here, we used fMRI at high field (7 T) to empirically test this hypothesis, by probing the cortical response to illusory figures in human V1 at different cortical depths [7-14]. We found that, whereas bottom-up stimulation activated all cortical layers, feedback activity induced by illusory figures led to a selective activation of the deep layers of V1. These results demonstrate the potential for non-invasive recordings of neural activity with laminar specificity in humans and elucidate the role of top-down signals during perceptual processing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Game-Based Augmented Visual Feedback for Enlarging Speech Movements in Parkinson's Disease.

PubMed

Yunusova, Yana; Kearney, Elaine; Kulkarni, Madhura; Haworth, Brandon; Baljko, Melanie; Faloutsos, Petros

2017-06-22

The purpose of this pilot study was to demonstrate the effect of augmented visual feedback on acquisition and short-term retention of a relatively simple instruction to increase movement amplitude during speaking tasks in patients with dysarthria due to Parkinson's disease (PD). Nine patients diagnosed with PD, hypokinetic dysarthria, and impaired speech intelligibility participated in a training program aimed at increasing the size of their articulatory (tongue) movements during sentences. Two sessions were conducted: a baseline and training session, followed by a retention session 48 hr later. At baseline, sentences were produced at normal, loud, and clear speaking conditions. Game-based visual feedback regarding the size of the articulatory working space (AWS) was presented during training. Eight of nine participants benefited from training, increasing their sentence AWS to a greater degree following feedback as compared with the baseline loud and clear conditions. The majority of participants were able to demonstrate the learned skill at the retention session. This study demonstrated the feasibility of augmented visual feedback via articulatory kinematics for training movement enlargement in patients with hypokinesia due to PD. https://doi.org/10.23641/asha.5116840.

A simulator for surgery training: optimal sensory stimuli in a bone pinning simulation

NASA Astrophysics Data System (ADS)

Daenzer, Stefan; Fritzsche, Klaus

2008-03-01

Currently available low cost haptic devices allow inexpensive surgical training with no risk to patients. Major drawbacks of lower cost devices include limited maximum feedback force and the incapability to expose occurring moments. Aim of this work was the design and implementation of a surgical simulator that allows the evaluation of multi-sensory stimuli in order to overcome the occurring drawbacks. The simulator was built following a modular architecture to allow flexible combinations and thorough evaluation of different multi-sensory feedback modules. A Kirschner-Wire (K-Wire) tibial fracture fixation procedure was defined and implemented as a first test scenario. A set of computational metrics has been derived from the clinical requirements of the task to objectively assess the trainees performance during simulation. Sensory feedback modules for haptic and visual feedback have been developed, each in a basic and additionally in an enhanced form. First tests have shown that specific visual concepts can overcome some of the drawbacks coming along with low cost haptic devices. The simulator, the metrics and the surgery scenario together represent an important step towards a better understanding of the perception of multi-sensory feedback in complex surgical training tasks. Field studies on top of the architecture can open the way to risk-less and inexpensive surgical simulations that can keep up with traditional surgical training.

How Do Batters Use Visual, Auditory, and Tactile Information about the Success of a Baseball Swing?

ERIC Educational Resources Information Center

Gray, Rob

2009-01-01

Bat/ball contact produces visual (the ball leaving the bat), auditory (the "crack" of the bat), and tactile (bat vibration) feedback about the success of the swing. We used a batting simulation to investigate how college baseball players use visual, tactile, and auditory feedback. In Experiment 1, swing accuracy (i.e., the lateral separation…

Visual and tactile information in double bass intonation control.

PubMed

Lage, Guilherme Menezes; Borém, Fausto; Vieira, Maurílio Nunes; Barreiros, João Pardal

2007-04-01

Traditionally, the teaching of intonation on the non-tempered orchestral strings (violin, viola, cello, and double bass) has resorted to the auditory and proprioceptive senses only. This study aims at understanding the role of visual and tactile information in the control of the non-tempered intonation of the acoustic double bass. Eight musicians played 11 trials of an atonal sequence of musical notes on two double basses of different sizes under different sensorial constraints. The accuracy of the played notes was analyzed by measuring their frequencies and comparing them with respective target values. The main finding was that the performance which integrated visual and tactile information was superior in relation to the other performances in the control of double bass intonation. This contradicts the traditional belief that proprioception and hearing are the most effective feedback information in the performance of stringed instruments.

Microstimulation of area V4 has little effect on spatial attention and on perception of phosphenes evoked in area V1

PubMed Central

Dagnino, Bruno; Gariel-Mathis, Marie-Alice

2014-01-01

Previous transcranial magnetic stimulation (TMS) studies suggested that feedback from higher to lower areas of the visual cortex is important for the access of visual information to awareness. However, the influence of cortico-cortical feedback on awareness and the nature of the feedback effects are not yet completely understood. In the present study, we used electrical microstimulation in the visual cortex of monkeys to test the hypothesis that cortico-cortical feedback plays a role in visual awareness. We investigated the interactions between the primary visual cortex (V1) and area V4 by applying microstimulation in both cortical areas at various delays. We report that the monkeys detected the phosphenes produced by V1 microstimulation but subthreshold V4 microstimulation did not influence V1 phosphene detection thresholds. A second experiment examined the influence of V4 microstimulation on the monkeys' ability to detect the dimming of one of three peripheral visual stimuli. Again, microstimulation of a group of V4 neurons failed to modulate the monkeys' perception of a stimulus in their receptive field. We conclude that conditions exist where microstimulation of area V4 has only a limited influence on visual perception. PMID:25392172

Microstimulation of area V4 has little effect on spatial attention and on perception of phosphenes evoked in area V1.

PubMed

Dagnino, Bruno; Gariel-Mathis, Marie-Alice; Roelfsema, Pieter R

2015-02-01

Previous transcranial magnetic stimulation (TMS) studies suggested that feedback from higher to lower areas of the visual cortex is important for the access of visual information to awareness. However, the influence of cortico-cortical feedback on awareness and the nature of the feedback effects are not yet completely understood. In the present study, we used electrical microstimulation in the visual cortex of monkeys to test the hypothesis that cortico-cortical feedback plays a role in visual awareness. We investigated the interactions between the primary visual cortex (V1) and area V4 by applying microstimulation in both cortical areas at various delays. We report that the monkeys detected the phosphenes produced by V1 microstimulation but subthreshold V4 microstimulation did not influence V1 phosphene detection thresholds. A second experiment examined the influence of V4 microstimulation on the monkeys' ability to detect the dimming of one of three peripheral visual stimuli. Again, microstimulation of a group of V4 neurons failed to modulate the monkeys' perception of a stimulus in their receptive field. We conclude that conditions exist where microstimulation of area V4 has only a limited influence on visual perception. Copyright © 2015 the American Physiological Society.

Integrative advances for OCT-guided ophthalmic surgery and intraoperative OCT: microscope integration, surgical instrumentation, and heads-up display surgeon feedback.

PubMed

Ehlers, Justis P; Srivastava, Sunil K; Feiler, Daniel; Noonan, Amanda I; Rollins, Andrew M; Tao, Yuankai K

2014-01-01

To demonstrate key integrative advances in microscope-integrated intraoperative optical coherence tomography (iOCT) technology that will facilitate adoption and utilization during ophthalmic surgery. We developed a second-generation prototype microscope-integrated iOCT system that interfaces directly with a standard ophthalmic surgical microscope. Novel features for improved design and functionality included improved profile and ergonomics, as well as a tunable lens system for optimized image quality and heads-up display (HUD) system for surgeon feedback. Novel material testing was performed for potential suitability for OCT-compatible instrumentation based on light scattering and transmission characteristics. Prototype surgical instruments were developed based on material testing and tested using the microscope-integrated iOCT system. Several surgical maneuvers were performed and imaged, and surgical motion visualization was evaluated with a unique scanning and image processing protocol. High-resolution images were successfully obtained with the microscope-integrated iOCT system with HUD feedback. Six semi-transparent materials were characterized to determine their attenuation coefficients and scatter density with an 830 nm OCT light source. Based on these optical properties, polycarbonate was selected as a material substrate for prototype instrument construction. A surgical pick, retinal forceps, and corneal needle were constructed with semi-transparent materials. Excellent visualization of both the underlying tissues and surgical instrument were achieved on OCT cross-section. Using model eyes, various surgical maneuvers were visualized, including membrane peeling, vessel manipulation, cannulation of the subretinal space, subretinal intraocular foreign body removal, and corneal penetration. Significant iterative improvements in integrative technology related to iOCT and ophthalmic surgery are demonstrated.

The Use of Visual Feedback During Signing: Evidence From Signers With Impaired Vision

PubMed Central

Korpics, Franco; Petronio, Karen

2009-01-01

The role of visual feedback during the production of American Sign Language was investigated by comparing the size of signing space during conversations and narrative monologues for normally sighted signers, signers with tunnel vision due to Usher syndrome, and functionally blind signers. The interlocutor for all groups was a normally sighted deaf person. Signers with tunnel vision produced a greater proportion of signs near the face than blind and normally sighted signers, who did not differ from each other. Both groups of visually impaired signers produced signs within a smaller signing space for conversations than for monologues, but we hypothesize that they did so for different reasons. Signers with tunnel vision may align their signing space with that of their interlocutor. In contrast, blind signers may enhance proprioceptive feedback by producing signs within an enlarged signing space for monologues, which do not require switching between tactile and visual signing. Overall, we hypothesize that signers use visual feedback to phonetically calibrate the dimensions of signing space, rather than to monitor language output. PMID:18495656

The use of visual feedback during signing: evidence from signers with impaired vision.

PubMed

Emmorey, Karen; Korpics, Franco; Petronio, Karen

2009-01-01

The role of visual feedback during the production of American Sign Language was investigated by comparing the size of signing space during conversations and narrative monologues for normally sighted signers, signers with tunnel vision due to Usher syndrome, and functionally blind signers. The interlocutor for all groups was a normally sighted deaf person. Signers with tunnel vision produced a greater proportion of signs near the face than blind and normally sighted signers, who did not differ from each other. Both groups of visually impaired signers produced signs within a smaller signing space for conversations than for monologues, but we hypothesize that they did so for different reasons. Signers with tunnel vision may align their signing space with that of their interlocutor. In contrast, blind signers may enhance proprioceptive feedback by producing signs within an enlarged signing space for monologues, which do not require switching between tactile and visual signing. Overall, we hypothesize that signers use visual feedback to phonetically calibrate the dimensions of signing space, rather than to monitor language output.

Locomotor sensory organization test: a novel paradigm for the assessment of sensory contributions in gait.

PubMed

Chien, Jung Hung; Eikema, Diderik-Jan Anthony; Mukherjee, Mukul; Stergiou, Nicholas

2014-12-01

Feedback based balance control requires the integration of visual, proprioceptive and vestibular input to detect the body's movement within the environment. When the accuracy of sensory signals is compromised, the system reorganizes the relative contributions through a process of sensory recalibration, for upright postural stability to be maintained. Whereas this process has been studied extensively in standing using the Sensory Organization Test (SOT), less is known about these processes in more dynamic tasks such as locomotion. In the present study, ten healthy young adults performed the six conditions of the traditional SOT to quantify standing postural control when exposed to sensory conflict. The same subjects performed these six conditions using a novel experimental paradigm, the Locomotor SOT (LSOT), to study dynamic postural control during walking under similar types of sensory conflict. To quantify postural control during walking, the net Center of Pressure sway variability was used. This corresponds to the Performance Index of the center of pressure trajectory, which is used to quantify postural control during standing. Our results indicate that dynamic balance control during locomotion in healthy individuals is affected by the systematic manipulation of multisensory inputs. The sway variability patterns observed during locomotion reflect similar balance performance with standing posture, indicating that similar feedback processes may be involved. However, the contribution of visual input is significantly increased during locomotion, compared to standing in similar sensory conflict conditions. The increased visual gain in the LSOT conditions reflects the importance of visual input for the control of locomotion. Since balance perturbations tend to occur in dynamic tasks and in response to environmental constraints not present during the SOT, the LSOT may provide additional information for clinical evaluation on healthy and deficient sensory processing.

Interactive Tools for Measuring Visual Scanning Performance and Reaction Time.

PubMed

Brooks, Johnell; Seeanner, Julia; Hennessy, Sarah; Manganelli, Joseph; Crisler, Matthew; Rosopa, Patrick; Jenkins, Casey; Anderson, Michael; Drouin, Nathalie; Belle, Leah; Truesdail, Constance; Tanner, Stephanie

Occupational therapists are constantly searching for engaging, high-technology interactive tasks that provide immediate feedback to evaluate and train clients with visual scanning deficits. This study examined the relationship between two tools: the VISION COACH™ interactive light board and the Functional Object Detection © (FOD) Advanced driving simulator scenario. Fifty-four healthy drivers, ages 21-66 yr, were divided into three age groups. Participants performed braking response and visual target (E) detection tasks of the FOD Advanced driving scenario, followed by two sets of three trials using the VISION COACH Full Field 60 task. Results showed no significant effect of age on FOD Advanced performance but a significant effect of age on VISION COACH performance. Correlations showed that participants' performance on both braking and E detection tasks were significantly positively correlated with performance on the VISION COACH (.37 < r < .40, p < .01). These tools provide new options for therapists. Copyright © 2017 by the American Occupational Therapy Association, Inc.

The quality of visual information about the lower extremities influences visuomotor coordination during virtual obstacle negotiation.

PubMed

Kim, Aram; Kretch, Kari S; Zhou, Zixuan; Finley, James M

2018-05-09

Successful negotiation of obstacles during walking relies on the integration of visual information about the environment with ongoing locomotor commands. When information about the body and environment are removed through occlusion of the lower visual field, individuals increase downward head pitch angle, reduce foot placement precision, and increase safety margins during crossing. However, whether these effects are mediated by loss of visual information about the lower extremities, the obstacle, or both remains to be seen. Here, we used a fully immersive, virtual obstacle negotiation task to investigate how visual information about the lower extremities is integrated with information about the environment to facilitate skillful obstacle negotiation. Participants stepped over virtual obstacles while walking on a treadmill with one of three types of visual feedback about the lower extremities: no feedback, end-point feedback, or a link-segment model. We found that absence of visual information about the lower extremities led to an increase in the variability of leading foot placement after crossing. The presence of a visual representation of the lower extremities promoted greater downward head pitch angle during the approach to and subsequent crossing of an obstacle. In addition, having greater downward head pitch was associated with closer placement of the trailing foot to the obstacle, further placement of the leading foot after the obstacle, and higher trailing foot clearance. These results demonstrate that the fidelity of visual information about the lower extremities influences both feed-forward and feedback aspects of visuomotor coordination during obstacle negotiation.

Directional errors of movements and their correction in a discrete tracking task. [pilot reaction time and sensorimotor performance

NASA Technical Reports Server (NTRS)

Jaeger, R. J.; Agarwal, G. C.; Gottlieb, G. L.

1978-01-01

Subjects can correct their own errors of movement more quickly than they can react to external stimuli by using three general categories of feedback: (1) knowledge of results, primarily visually mediated; (2) proprioceptive or kinaesthetic such as from muscle spindles and joint receptors, and (3) corollary discharge or efference copy within the central nervous system. The effects of these feedbacks on simple reaction time, choice reaction time, and error correction time were studied in four normal human subjects. The movement used was plantarflexion and dorsiflexion of the ankle joint. The feedback loops were modified, by changing the sign of the visual display to alter the subject's perception of results, and by applying vibration at 100 Hz simultaneously to both the agonist and antagonist muscles of the ankle joint. The central processing was interfered with when the subjects were given moderate doses of alcohol (blood alcohol concentration levels of up to 0.07%). Vibration and alcohol increase both the simple and choice reaction times but not the error correction time.

System identification and sensorimotor determinants of flight maneuvers in an insect

NASA Astrophysics Data System (ADS)

Sponberg, Simon; Hall, Robert; Roth, Eatai

Locomotor maneuvers are inherently closed-loop processes. They are generally characterized by the integration of multiple sensory inputs and adaptation or learning over time. To probe sensorimotor processing we take a system identification approach treating the underlying physiological systems as dynamic processes and altering the feedback topology in experiment and analysis. As a model system, we use agile hawk moths (Manduca sexta), which feed from real and robotic flowers while hovering in mid air. Moths rely on vision and mechanosensation to track floral targets and can do so at exceptionally low luminance levels despite hovering being a mechanically unstable behavior that requires neural feedback to stabilize. By altering the sensory environment and placing mechanical and visual signals in conflict we show a surprisingly simple linear summation of visual and mechanosensation produces a generative prediction of behavior to novel stimuli. Tracking performance is also limited more by the mechanics of flight than the magnitude of the sensory cue. A feedback systems approach to locomotor control results in new insights into how behavior emerges from the interaction of nonlinear physiological systems.

Helping students revise disruptive experientially supported ideas about thermodynamics: Computer visualizations and tactile models

NASA Astrophysics Data System (ADS)

Clark, Douglas; Jorde, Doris

2004-01-01

This study analyzes the impact of an integrated sensory model within a thermal equilibrium visualization. We hypothesized that this intervention would not only help students revise their disruptive experientially supported ideas about why objects feel hot or cold, but also increase their understanding of thermal equilibrium. The analysis synthesizes test data and interviews to measure the impact of this strategy. Results show that students in the experimental tactile group significantly outperform their control group counterparts on posttests and delayed posttests, not only on tactile explanations, but also on thermal equilibrium explanations. Interview transcripts of experimental and control group students corroborate these findings. Discussion addresses improving the tactile model as well as application of the strategy to other science topics. The discussion also considers possible incorporation of actual kinetic or thermal haptic feedback to reinforce the current audio and visual feedback of the visualization. This research builds on the conceptual change literature about the nature and role of students' experientially supported ideas as well as our understanding of curriculum and visualization design to support students in learning about thermodynamics, a science topic on which students perform poorly as shown by the National Assessment of Educational Progress (NAEP) and Third International Mathematics and Science Study (TIMSS) studies.

Real-time visual biofeedback during weight bearing improves therapy compliance in patients following lower extremity fractures.

PubMed

Raaben, Marco; Holtslag, Herman R; Leenen, Luke P H; Augustine, Robin; Blokhuis, Taco J

2018-01-01

Individuals with lower extremity fractures are often instructed on how much weight to bear on the affected extremity. Previous studies have shown limited therapy compliance in weight bearing during rehabilitation. In this study we investigated the effect of real-time visual biofeedback on weight bearing in individuals with lower extremity fractures in two conditions: full weight bearing and touch-down weight bearing. 11 participants with full weight bearing and 12 participants with touch-down weight bearing after lower extremity fractures have been measured with an ambulatory biofeedback system. The participants first walked 15m and the biofeedback system was only used to register the weight bearing. The same protocol was then repeated with real-time visual feedback during weight bearing. The participants could thereby adapt their loading to the desired level and improve therapy compliance. In participants with full weight bearing, real-time visual biofeedback resulted in a significant increase in loading from 50.9±7.51% bodyweight (BW) without feedback to 63.2±6.74%BW with feedback (P=0.0016). In participants with touch-down weight bearing, the exerted lower extremity load decreased from 16.7±9.77kg without feedback to 10.27±4.56kg with feedback (P=0.0718). More important, the variance between individual steps significantly decreased after feedback (P=0.018). Ambulatory monitoring weight bearing after lower extremity fractures showed that therapy compliance is low, both in full and touch-down weight bearing. Real-time visual biofeedback resulted in significantly higher peak loads in full weight bearing and increased accuracy of individual steps in touch-down weight bearing. Real-time visual biofeedback therefore results in improved therapy compliance after lower extremity fractures. Copyright © 2017 Elsevier B.V. All rights reserved.

Performance of cardiopulmonary resuscitation feedback systems in a long-distance train with distributed traction.

PubMed

González-Otero, Digna M; de Gauna, Sofía Ruiz; Ruiz, Jesus; Rivero, Raquel; Gutierrez, J J; Saiz, Purificación; Russell, James K

2018-04-20

Out-of-hospital cardiac arrest is common in public locations, including public transportation sites. Feedback devices are increasingly being used to improve chest-compression quality. However, their performance during public transportation has not been studied yet. To test two CPR feedback devices representative of the current technologies (accelerometer and electromag- netic-field) in a long-distance train. Volunteers applied compressions on a manikin during the train route using both feedback devices. Depth and rate measurements computed by the devices were compared to the gold-standard values. Sixty-four 4-min records were acquired. The accelerometer-based device provided visual help in all experiments. Median absolute errors in depth and rate were 2.4 mm and 1.3 compressions per minute (cpm) during conventional speed, and 2.5 mm and 1.2 cpm during high speed. The electromagnetic-field-based device never provided CPR feedback; alert messages were shown instead. However, measurements were stored in its internal memory. Absolute errors for depth and rate were 2.6 mm and 0.7 cpm during conventional speed, and 2.6 mm and 0.7 cpm during high speed. Both devices were accurate despite the accelerations and the electromagnetic interferences induced by the train. However, the electromagnetic-field-based device would require modifications to avoid excessive alerts impeding feedback.

Alterations in Neural Control of Constant Isometric Contraction with the Size of Error Feedback

PubMed Central

Hwang, Ing-Shiou; Lin, Yen-Ting; Huang, Wei-Min; Yang, Zong-Ru; Hu, Chia-Ling; Chen, Yi-Ching

2017-01-01

Discharge patterns from a population of motor units (MUs) were estimated with multi-channel surface electromyogram and signal processing techniques to investigate parametric differences in low-frequency force fluctuations, MU discharges, and force-discharge relation during static force-tracking with varying sizes of execution error presented via visual feedback. Fourteen healthy adults produced isometric force at 10% of maximal voluntary contraction through index abduction under three visual conditions that scaled execution errors with different amplification factors. Error-augmentation feedback that used a high amplification factor (HAF) to potentiate visualized error size resulted in higher sample entropy, mean frequency, ratio of high-frequency components, and spectral dispersion of force fluctuations than those of error-reducing feedback using a low amplification factor (LAF). In the HAF condition, MUs with relatively high recruitment thresholds in the dorsal interosseous muscle exhibited a larger coefficient of variation for inter-spike intervals and a greater spectral peak of the pooled MU coherence at 13–35 Hz than did those in the LAF condition. Manipulation of the size of error feedback altered the force-discharge relation, which was characterized with non-linear approaches such as mutual information and cross sample entropy. The association of force fluctuations and global discharge trace decreased with increasing error amplification factor. Our findings provide direct neurophysiological evidence that favors motor training using error-augmentation feedback. Amplification of the visualized error size of visual feedback could enrich force gradation strategies during static force-tracking, pertaining to selective increases in the discharge variability of higher-threshold MUs that receive greater common oscillatory inputs in the β-band. PMID:28125658

Evaluation of Physiological and Psychological Impairment of Human Performance in Cold Stressed Subjects

DTIC Science & Technology

1990-03-23

defined (personal communciation between R. Pozos and Simon, 1985). In summary, there have been studies dealing with shivering which indicate that the...microcomputer (IBM PS/2, Model 30/286). The Firearms Training System combines features of several technologies, notably: interactive video-disc/ computer ...technology and laser designator/camera/ computer /target-hit generation, which provides for immediate visual performance feedback. The subject is

Congenitally blind individuals rapidly adapt to coriolis force perturbations of their reaching movements

NASA Technical Reports Server (NTRS)

DiZio, P.; Lackner, J. R.

2000-01-01

Reaching movements made to visual targets in a rotating room are initially deviated in path and endpoint in the direction of transient Coriolis forces generated by the motion of the arm relative to the rotating environment. With additional reaches, movements become progressively straighter and more accurate. Such adaptation can occur even in the absence of visual feedback about movement progression or terminus. Here we examined whether congenitally blind and sighted subjects without visual feedback would demonstrate adaptation to Coriolis forces when they pointed to a haptically specified target location. Subjects were tested pre-, per-, and postrotation at 10 rpm counterclockwise. Reaching to straight ahead targets prerotation, both groups exhibited slightly curved paths. Per-rotation, both groups showed large initial deviations of movement path and curvature but within 12 reaches on average had returned to prerotation curvature levels and endpoints. Postrotation, both groups showed mirror image patterns of curvature and endpoint to the per-rotation pattern. The groups did not differ significantly on any of the performance measures. These results provide compelling evidence that motor adaptation to Coriolis perturbations can be achieved on the basis of proprioceptive, somatosensory, and motor information in the complete absence of visual experience.

The role of vision in odor-plume tracking by walking and flying insects.

PubMed

Willis, Mark A; Avondet, Jennifer L; Zheng, Elizabeth

2011-12-15

The walking paths of male cockroaches, Periplaneta americana, tracking point-source plumes of female pheromone often appear similar in structure to those observed from flying male moths. Flying moths use visual-flow-field feedback of their movements to control steering and speed over the ground and to detect the wind speed and direction while tracking plumes of odors. Walking insects are also known to use flow field cues to steer their trajectories. Can the upwind steering we observe in plume-tracking walking male cockroaches be explained by visual-flow-field feedback, as in flying moths? To answer this question, we experimentally occluded the compound eyes and ocelli of virgin P. americana males, separately and in combination, and challenged them with different wind and odor environments in our laboratory wind tunnel. They were observed responding to: (1) still air and no odor, (2) wind and no odor, (3) a wind-borne point-source pheromone plume and (4) a wide pheromone plume in wind. If walking cockroaches require visual cues to control their steering with respect to their environment, we would expect their tracks to be less directed and more variable if they cannot see. Instead, we found few statistically significant differences among behaviors exhibited by intact control cockroaches or those with their eyes occluded, under any of our environmental conditions. Working towards our goal of a comprehensive understanding of chemo-orientation in insects, we then challenged flying and walking male moths to track pheromone plumes with and without visual feedback. Neither walking nor flying moths performed as well as walking cockroaches when there was no visual information available.

The role of vision in odor-plume tracking by walking and flying insects

PubMed Central

Willis, Mark A.; Avondet, Jennifer L.; Zheng, Elizabeth

2011-01-01

SUMMARY The walking paths of male cockroaches, Periplaneta americana, tracking point-source plumes of female pheromone often appear similar in structure to those observed from flying male moths. Flying moths use visual-flow-field feedback of their movements to control steering and speed over the ground and to detect the wind speed and direction while tracking plumes of odors. Walking insects are also known to use flow field cues to steer their trajectories. Can the upwind steering we observe in plume-tracking walking male cockroaches be explained by visual-flow-field feedback, as in flying moths? To answer this question, we experimentally occluded the compound eyes and ocelli of virgin P. americana males, separately and in combination, and challenged them with different wind and odor environments in our laboratory wind tunnel. They were observed responding to: (1) still air and no odor, (2) wind and no odor, (3) a wind-borne point-source pheromone plume and (4) a wide pheromone plume in wind. If walking cockroaches require visual cues to control their steering with respect to their environment, we would expect their tracks to be less directed and more variable if they cannot see. Instead, we found few statistically significant differences among behaviors exhibited by intact control cockroaches or those with their eyes occluded, under any of our environmental conditions. Working towards our goal of a comprehensive understanding of chemo-orientation in insects, we then challenged flying and walking male moths to track pheromone plumes with and without visual feedback. Neither walking nor flying moths performed as well as walking cockroaches when there was no visual information available. PMID:22116754

Effectiveness of mirror therapy, motor imagery, and virtual feedback on phantom limb pain following amputation: A systematic review.

PubMed

Herrador Colmenero, Laura; Perez Marmol, Jose Manuel; Martí-García, Celia; Querol Zaldivar, María de Los Ángeles; Tapia Haro, Rosa María; Castro Sánchez, Adelaida María; Aguilar-Ferrándiz, María Encarnación

2018-06-01

Phantom limb pain is reported in 50%-85% of people with amputation. Clinical interventions in treating central pain, such as mirror therapy, motor imagery, or virtual visual feedback, could redound in benefits to amputee patients with phantom limb pain. To provide an overview of the effectiveness of different techniques for treating phantom limb pain in amputee patients. Systematic review. A computerized literature search up to April 2017 was performed using the following databases: PubMed, Scopus, CINAHL, MEDLINE, ProQuest, PEDro, EBSCOhost, and Cochrane Plus. Methodological quality and internal validity score of each study were assessed using PEDro scale. For data synthesis, qualitative methods from the Cochrane Back Review Group were applied. In all, 12 studies met our inclusion criteria, where 9 were rated as low methodological quality and 3 rated moderate quality. All studies showed a significant reduction in pain, but there was heterogeneity among subjects and methodologies and any high-quality clinical trial (PEDro score ≤8; internal validity score ≤5) was not found. Mirror therapy, motor imaginary, and virtual visual feedback reduce phantom limb pain; however, there is limited scientific evidence supporting their effectiveness. Future studies should include designs with more solid research methods, exploring short- and long-term benefits of these therapies. Clinical relevance This systematic review investigates the effectiveness of mirror therapy, motor imagery, and virtual visual feedback on phantom limb pain, summarizing the currently published trials and evaluating the research quality. Although these interventions have positive benefits in phantom limb pain, there is still a lack of evidence for supporting their effectiveness.

Development of closed-loop neural interface technology in a rat model: combining motor cortex operant conditioning with visual cortex microstimulation.

PubMed

Marzullo, Timothy Charles; Lehmkuhle, Mark J; Gage, Gregory J; Kipke, Daryl R

2010-04-01

Closed-loop neural interface technology that combines neural ensemble decoding with simultaneous electrical microstimulation feedback is hypothesized to improve deep brain stimulation techniques, neuromotor prosthetic applications, and epilepsy treatment. Here we describe our iterative results in a rat model of a sensory and motor neurophysiological feedback control system. Three rats were chronically implanted with microelectrode arrays in both the motor and visual cortices. The rats were subsequently trained over a period of weeks to modulate their motor cortex ensemble unit activity upon delivery of intra-cortical microstimulation (ICMS) of the visual cortex in order to receive a food reward. Rats were given continuous feedback via visual cortex ICMS during the response periods that was representative of the motor cortex ensemble dynamics. Analysis revealed that the feedback provided the animals with indicators of the behavioral trials. At the hardware level, this preparation provides a tractable test model for improving the technology of closed-loop neural devices.

The persistence of a visual dominance effect in a telemanipulator task: A comparison between visual and electrotactile feedback

NASA Technical Reports Server (NTRS)

Gaillard, J. P.

1981-01-01

The possibility to use an electrotactile stimulation in teleoperation and to observe the interpretation of such information as a feedback to the operator was investigated. It is proposed that visual feedback is more informative than an electrotactile one; and that complex electrotactile feedback slows down both the motor decision and motor response processes, is processed as an all or nothing signal, and bypasses the receptive structure and accesses directly in a working memory where information is sequentially processed and where memory is limited in treatment capacity. The electrotactile stimulation is used as an alerting signal. It is suggested that the visual dominance effect is the result of the advantage of both a transfer function and a sensory memory register where information is pretreated and memorized for a short time. It is found that dividing attention has an effect on the acquisition of the information but not on the subsequent decision processes.

A direct comparison of short-term audiomotor and visuomotor memory.

PubMed

Ward, Amanda M; Loucks, Torrey M; Ofori, Edward; Sosnoff, Jacob J

2014-04-01

Audiomotor and visuomotor short-term memory are required for an important variety of skilled movements but have not been compared in a direct manner previously. Audiomotor memory capacity might be greater to accommodate auditory goals that are less directly related to movement outcome than for visually guided tasks. Subjects produced continuous isometric force with the right index finger under auditory and visual feedback. During the first 10 s of each trial, subjects received continuous auditory or visual feedback. For the following 15 s, feedback was removed but the force had to be maintained accurately. An internal effort condition was included to test memory capacity in the same manner but without external feedback. Similar decay times of ~5-6 s were found for vision and audition but the decay time for internal effort was ~4 s. External feedback thus provides an advantage in maintaining a force level after feedback removal, but may not exclude some contribution from a sense of effort. Short-term memory capacity appears longer than certain previous reports but there may not be strong distinctions in capacity across different sensory modalities, at least for isometric force.

Learning and altering behaviours by reinforcement: neurocognitive differences between children and adults.

PubMed

Shephard, E; Jackson, G M; Groom, M J

2014-01-01

This study examined neurocognitive differences between children and adults in the ability to learn and adapt simple stimulus-response associations through feedback. Fourteen typically developing children (mean age=10.2) and 15 healthy adults (mean age=25.5) completed a simple task in which they learned to associate visually presented stimuli with manual responses based on performance feedback (acquisition phase), and then reversed and re-learned those associations following an unexpected change in reinforcement contingencies (reversal phase). Electrophysiological activity was recorded throughout task performance. We found no group differences in learning-related changes in performance (reaction time, accuracy) or in the amplitude of event-related potentials (ERPs) associated with stimulus processing (P3 ERP) or feedback processing (feedback-related negativity; FRN) during the acquisition phase. However, children's performance was significantly more disrupted by the reversal than adults and FRN amplitudes were significantly modulated by the reversal phase in children but not adults. These findings indicate that children have specific difficulties with reinforcement learning when acquired behaviours must be altered. This may be caused by the added demands on immature executive functioning, specifically response monitoring, created by the requirement to reverse the associations, or a developmental difference in the way in which children and adults approach reinforcement learning. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Similar brain networks for detecting visuo-motor and visuo-proprioceptive synchrony.

PubMed

Balslev, Daniela; Nielsen, Finn A; Lund, Torben E; Law, Ian; Paulson, Olaf B

2006-05-15

The ability to recognize feedback from own movement as opposed to the movement of someone else is important for motor control and social interaction. The neural processes involved in feedback recognition are incompletely understood. Two competing hypotheses have been proposed: the stimulus is compared with either (a) the proprioceptive feedback or with (b) the motor command and if they match, then the external stimulus is identified as feedback. Hypothesis (a) predicts that the neural mechanisms or brain areas involved in distinguishing self from other during passive and active movement are similar, whereas hypothesis (b) predicts that they are different. In this fMRI study, healthy subjects saw visual cursor movement that was either synchronous or asynchronous with their active or passive finger movements. The aim was to identify the brain areas where the neural activity depended on whether the visual stimulus was feedback from own movement and to contrast the functional activation maps for active and passive movement. We found activity increases in the right temporoparietal cortex in the condition with asynchronous relative to synchronous visual feedback from both active and passive movements. However, no statistically significant difference was found between these sets of activated areas when the active and passive movement conditions were compared. With a posterior probability of 0.95, no brain voxel had a contrast effect above 0.11% of the whole-brain mean signal. These results do not support the hypothesis that recognition of visual feedback during active and passive movement relies on different brain areas.

Automated numerical simulation of biological pattern formation based on visual feedback simulation framework

PubMed Central

Sun, Mingzhu; Xu, Hui; Zeng, Xingjuan; Zhao, Xin

2017-01-01

There are various fantastic biological phenomena in biological pattern formation. Mathematical modeling using reaction-diffusion partial differential equation systems is employed to study the mechanism of pattern formation. However, model parameter selection is both difficult and time consuming. In this paper, a visual feedback simulation framework is proposed to calculate the parameters of a mathematical model automatically based on the basic principle of feedback control. In the simulation framework, the simulation results are visualized, and the image features are extracted as the system feedback. Then, the unknown model parameters are obtained by comparing the image features of the simulation image and the target biological pattern. Considering two typical applications, the visual feedback simulation framework is applied to fulfill pattern formation simulations for vascular mesenchymal cells and lung development. In the simulation framework, the spot, stripe, labyrinthine patterns of vascular mesenchymal cells, the normal branching pattern and the branching pattern lacking side branching for lung branching are obtained in a finite number of iterations. The simulation results indicate that it is easy to achieve the simulation targets, especially when the simulation patterns are sensitive to the model parameters. Moreover, this simulation framework can expand to other types of biological pattern formation. PMID:28225811

A unified framework for image retrieval using keyword and visual features.

PubMed

Jing, Feng; Li, Mingling; Zhang, Hong-Jiang; Zhang, Bo

2005-07-01

In this paper, a unified image retrieval framework based on both keyword annotations and visual features is proposed. In this framework, a set of statistical models are built based on visual features of a small set of manually labeled images to represent semantic concepts and used to propagate keywords to other unlabeled images. These models are updated periodically when more images implicitly labeled by users become available through relevance feedback. In this sense, the keyword models serve the function of accumulation and memorization of knowledge learned from user-provided relevance feedback. Furthermore, two sets of effective and efficient similarity measures and relevance feedback schemes are proposed for query by keyword scenario and query by image example scenario, respectively. Keyword models are combined with visual features in these schemes. In particular, a new, entropy-based active learning strategy is introduced to improve the efficiency of relevance feedback for query by keyword. Furthermore, a new algorithm is proposed to estimate the keyword features of the search concept for query by image example. It is shown to be more appropriate than two existing relevance feedback algorithms. Experimental results demonstrate the effectiveness of the proposed framework.

Automated numerical simulation of biological pattern formation based on visual feedback simulation framework.

PubMed

Sun, Mingzhu; Xu, Hui; Zeng, Xingjuan; Zhao, Xin

2017-01-01

There are various fantastic biological phenomena in biological pattern formation. Mathematical modeling using reaction-diffusion partial differential equation systems is employed to study the mechanism of pattern formation. However, model parameter selection is both difficult and time consuming. In this paper, a visual feedback simulation framework is proposed to calculate the parameters of a mathematical model automatically based on the basic principle of feedback control. In the simulation framework, the simulation results are visualized, and the image features are extracted as the system feedback. Then, the unknown model parameters are obtained by comparing the image features of the simulation image and the target biological pattern. Considering two typical applications, the visual feedback simulation framework is applied to fulfill pattern formation simulations for vascular mesenchymal cells and lung development. In the simulation framework, the spot, stripe, labyrinthine patterns of vascular mesenchymal cells, the normal branching pattern and the branching pattern lacking side branching for lung branching are obtained in a finite number of iterations. The simulation results indicate that it is easy to achieve the simulation targets, especially when the simulation patterns are sensitive to the model parameters. Moreover, this simulation framework can expand to other types of biological pattern formation.

Visual feedback in stuttering therapy

NASA Astrophysics Data System (ADS)

Smolka, Elzbieta

1997-02-01

The aim of this paper is to present the results concerning the influence of visual echo and reverberation on the speech process of stutterers. Visual stimuli along with the influence of acoustic and visual-acoustic stimuli have been compared. Following this the methods of implementing visual feedback with the aid of electroluminescent diodes directed by speech signals have been presented. The concept of a computerized visual echo based on the acoustic recognition of Polish syllabic vowels has been also presented. All the research nd trials carried out at our center, aside from cognitive aims, generally aim at the development of new speech correctors to be utilized in stuttering therapy.

Ultra-Rapid serial visual presentation reveals dynamics of feedforward and feedback processes in the ventral visual pathway.

PubMed

Mohsenzadeh, Yalda; Qin, Sheng; Cichy, Radoslaw M; Pantazis, Dimitrios

2018-06-21

Human visual recognition activates a dense network of overlapping feedforward and recurrent neuronal processes, making it hard to disentangle processing in the feedforward from the feedback direction. Here, we used ultra-rapid serial visual presentation to suppress sustained activity that blurs the boundaries of processing steps, enabling us to resolve two distinct stages of processing with MEG multivariate pattern classification. The first processing stage was the rapid activation cascade of the bottom-up sweep, which terminated early as visual stimuli were presented at progressively faster rates. The second stage was the emergence of categorical information with peak latency that shifted later in time with progressively faster stimulus presentations, indexing time-consuming recurrent processing. Using MEG-fMRI fusion with representational similarity, we localized recurrent signals in early visual cortex. Together, our findings segregated an initial bottom-up sweep from subsequent feedback processing, and revealed the neural signature of increased recurrent processing demands for challenging viewing conditions. © 2018, Mohsenzadeh et al.

Biophysical network modeling of the dLGN circuit: Effects of cortical feedback on spatial response properties of relay cells

PubMed Central

Martínez-Cañada, Pablo; Halnes, Geir; Fyhn, Marianne

2018-01-01

Despite half-a-century of research since the seminal work of Hubel and Wiesel, the role of the dorsal lateral geniculate nucleus (dLGN) in shaping the visual signals is not properly understood. Placed on route from retina to primary visual cortex in the early visual pathway, a striking feature of the dLGN circuit is that both the relay cells (RCs) and interneurons (INs) not only receive feedforward input from retinal ganglion cells, but also a prominent feedback from cells in layer 6 of visual cortex. This feedback has been proposed to affect synchronicity and other temporal properties of the RC firing. It has also been seen to affect spatial properties such as the center-surround antagonism of thalamic receptive fields, i.e., the suppression of the response to very large stimuli compared to smaller, more optimal stimuli. Here we explore the spatial effects of cortical feedback on the RC response by means of a a comprehensive network model with biophysically detailed, single-compartment and multicompartment neuron models of RCs, INs and a population of orientation-selective layer 6 simple cells, consisting of pyramidal cells (PY). We have considered two different arrangements of synaptic feedback from the ON and OFF zones in the visual cortex to the dLGN: phase-reversed (‘push-pull’) and phase-matched (‘push-push’), as well as different spatial extents of the corticothalamic projection pattern. Our simulation results support that a phase-reversed arrangement provides a more effective way for cortical feedback to provide the increased center-surround antagonism seen in experiments both for flashing spots and, even more prominently, for patch gratings. This implies that ON-center RCs receive direct excitation from OFF-dominated cortical cells and indirect inhibitory feedback from ON-dominated cortical cells. The increased center-surround antagonism in the model is accompanied by spatial focusing, i.e., the maximum RC response occurs for smaller stimuli when feedback is present. PMID:29377888

Visualizing Syllables: Real-Time Computerized Feedback within a Speech-Language Intervention

ERIC Educational Resources Information Center

DeThorne, Laura; Aparicio Betancourt, Mariana; Karahalios, Karrie; Halle, Jim; Bogue, Ellen

2015-01-01

Computerized technologies now offer unprecedented opportunities to provide real-time visual feedback to facilitate children's speech-language development. We employed a mixed-method design to examine the effectiveness of two speech-language interventions aimed at facilitating children's multisyllabic productions: one incorporated a novel…

The Inversion of Sensory Processing by Feedback Pathways: A Model of Visual Cognitive Functions.

ERIC Educational Resources Information Center

Harth, E.; And Others

1987-01-01

Explains the hierarchic structure of the mammalian visual system. Proposes a model in which feedback pathways serve to modify sensory stimuli in ways that enhance and complete sensory input patterns. Investigates the functioning of the system through computer simulations. (ML)

A real-time plantar pressure feedback device for foot unloading.

PubMed

Femery, Virginie G; Moretto, Pierre G; Hespel, Jean-Michel G; Thévenon, André; Lensel, Ghislaine

2004-10-01

To develop and test a plantar pressure control device that provides both visual and auditory feedback and is suitable for correcting plantar pressure distribution patterns in persons susceptible to neuropathic foot ulceration. Pilot test. Sports medicine laboratory in a university in France. One healthy man in his mid thirties. Not applicable. Main outcome measures A device was developed based on real-time feedback, incorporating an acoustic alarm and visual signals, adjusted to a specific pressure load. Plantar pressure measured during walking, at 6 sensor locations over 27 steps under 2 different conditions: (1) natural and (2) unloaded in response to device feedback. The subject was able to modify his gait in response to the auditory and visual signals. He did not compensate for the decrease of peak pressure under the first metarsal by increasing the duration of the load shift under this area. Gait pattern modification centered on a mediolateral load shift. The auditory signal provided a warning system alerting the user to potentially harmful plantar pressures. The visual signal warned of the degree of pressure. People who have lost nociceptive perception, as in cases of diabetic neuropathy, may be able to change their walking pattern in response to the feedback provided by this device. The visual may have diagnostic value in determining plantar pressures in such patients. This pilot test indicates that further studies are warranted.

Explicit knowledge about the availability of visual feedback affects grasping with the left but not the right hand.

PubMed

Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

2014-01-01

Previous research (Whitwell et al. in Exp Brain Res 188:603-611, 2008; Whitwell and Goodale in Exp Brain Res 194:619-629, 2009) has shown that trial history, but not anticipatory knowledge about the presence or absence of visual feedback on an upcoming trial, plays a vital role in determining how that feedback is exploited when grasping with the right hand. Nothing is known about how the non-dominant left hand behaves under the same feedback regimens. In present study, therefore, we compared peak grip aperture (PGA) for left- and right-hand grasps executed with and without visual feedback (i.e., closed- vs. open-loop conditions) in right-handed individuals under three different trial schedules: the feedback conditions were blocked separately, they were randomly interleaved, or they were alternated. When feedback conditions were blocked, the PGA was much larger for open-loop trials as compared to closed-loop trials, although this difference was more pronounced for right-hand grasps than left-hand grasps. Like Whitwell et al., we found that mixing open- and closed-loop trials together, compared to blocking them separately, homogenized the PGA for open- and closed-loop grasping in the right hand (i.e., the PGAs became smaller on open-loop trials and larger on closed-loop trials). In addition, the PGAs for right-hand grasps were entirely determined by trial history and not by knowledge of whether or not visual feedback would be available on an upcoming trial. In contrast to grasps made with the right hand, grasps made by the left hand were affected both by trial history and by anticipatory knowledge of the upcoming visual feedback condition. But these effects were observed only on closed-loop trials, i.e., the PGAs of grasps made with the left hand on closed-loop trials were smaller when participants could anticipate the availability of feedback on an upcoming trial (alternating trials) than when they could not (randomized trials). In contrast, grasps made with the left hand on open-loop trials exhibited the same large PGAs under all feedback schedules: blocked, random, or alternating. In other words, there was no evidence for homogenization. Taken together, these results suggest that in addition to the real-time demands of the task, such as the target's size and position and the availability of visual feedback, the initial (i.e., pre-movement) programming of right-hand grasping relies on what happened on the previous trial, whereas the programming of left-hand grasping is more cognitively supervised and exploits explicit information about trial order to prepare for an upcoming trial.

Counterintuitive effects of negative social feedback on attention.

PubMed

Anderson, Brian A

2017-04-01

Which stimuli we pay attention to is strongly influenced by learning. Stimuli previously associated with reward outcomes, such as money and food, and stimuli previously associated with aversive outcomes, such as monetary loss and electric shock, automatically capture attention. Social reward (happy expressions) can bias attention towards associated stimuli, but the role of negative social feedback in biasing attentional selection remains unexplored. On the one hand, negative social feedback often serves to discourage particular behaviours. If attentional selection can be curbed much like any other behavioural preference, we might expect stimuli associated with negative social feedback to be more readily ignored. On the other hand, if negative social feedback influences attention in the same way that other aversive outcomes do, such feedback might ironically bias attention towards the stimuli it is intended to discourage selection of. In the present study, participants first completed a training phase in which colour targets were associated with negative social feedback. Then, in a subsequent test phase, these same colour stimuli served as task-irrelevant distractors during a visual search task. The results strongly support the latter interpretation in that stimuli previously associated with negative social feedback impaired search performance.

Low-Cost Robotic Assessment of Visuo-Motor Deficits in Alzheimer's Disease.

PubMed

Bartoli, Eleonora; Caso, Francesca; Magnani, Giuseppe; Baud-Bovy, Gabriel

2017-07-01

A low-cost robotic interface was used to assess the visuo-motor performance of patients with Alzheimer's disease (AD). Twenty AD patients and twenty age-matched controls participated in this work. The battery of tests included simple reaction times, position tracking, and stabilization tasks performed with both hands. The regularity, velocity, visual and haptic feedback were manipulated to vary movement complexity. Reaction times and movement tracking error were analyzed. Results show a marked group effect on a subset of conditions, in particular when the patients could not rely on the visual feedback of hand movement. The visuo-motor performance correlated with the measures of global cognitive functioning and with different memory-related abilities. Our results support the hypothesis that the ability to recall and use visuo-spatial associations might underlie the impairment in complex motor behavior that has been reported in AD patients. Importantly, the patients had preserved learning effects across sessions, which might relate to visuo-motor deficits being less evident in every-day life and clinical assessments. This robotic assessment, lasting less than 1 h, provides detailed information about the integrity of visuo-motor abilities. The data can aid the understanding of the complex pattern of deficits that characterizes this pervasive disease.

Temporally flexible feedback signal to foveal cortex for peripheral object recognition

PubMed Central

Fan, Xiaoxu; Wang, Lan; Shao, Hanyu; Kersten, Daniel; He, Sheng

2016-01-01

Recent studies have shown that information from peripherally presented images is present in the human foveal retinotopic cortex, presumably because of feedback signals. We investigated this potential feedback signal by presenting noise in fovea at different object–noise stimulus onset asynchronies (SOAs), whereas subjects performed a discrimination task on peripheral objects. Results revealed a selective impairment of performance when foveal noise was presented at 250-ms SOA, but only for tasks that required comparing objects’ spatial details, suggesting a task- and stimulus-dependent foveal processing mechanism. Critically, the temporal window of foveal processing was shifted when mental rotation was required for the peripheral objects, indicating that the foveal retinotopic processing is not automatically engaged at a fixed time following peripheral stimulation; rather, it occurs at a stage when detailed information is required. Moreover, fMRI measurements using multivoxel pattern analysis showed that both image and object category-relevant information of peripheral objects was represented in the foveal cortex. Taken together, our results support the hypothesis of a temporally flexible feedback signal to the foveal retinotopic cortex when discriminating objects in the visual periphery. PMID:27671651

Adaptive Locomotor Behavior in Larval Zebrafish

PubMed Central

Portugues, Ruben; Engert, Florian

2011-01-01

In this study we report that larval zebrafish display adaptive locomotor output that can be driven by unexpected visual feedback. We develop a new assay that addresses visuomotor integration in restrained larval zebrafish. The assay involves a closed-loop environment in which the visual feedback a larva receives depends on its own motor output in a way that resembles freely swimming conditions. The experimenter can control the gain of this closed feedback loop, so that following a given motor output the larva experiences more or less visual feedback depending on whether the gain is high or low. We show that increases and decreases in this gain setting result in adaptive changes in behavior that lead to a generalized decrease or increase of motor output, respectively. Our behavioral analysis shows that both the duration and tail beat frequency of individual swim bouts can be modified, as well as the frequency with which bouts are elicited. These changes can be implemented rapidly, following an exposure to a new gain of just 175 ms. In addition, modifications in some behavioral parameters accumulate over tens of seconds and effects last for at least 30 s from trial to trial. These results suggest that larvae establish an internal representation of the visual feedback expected from a given motor output and that the behavioral modifications are driven by an error signal that arises from the discrepancy between this expectation and the actual visual feedback. The assay we develop presents a unique possibility for studying visuomotor integration using imaging techniques available in the larval zebrafish. PMID:21909325

Adaptive locomotor behavior in larval zebrafish.

PubMed

Portugues, Ruben; Engert, Florian

2011-01-01

In this study we report that larval zebrafish display adaptive locomotor output that can be driven by unexpected visual feedback. We develop a new assay that addresses visuomotor integration in restrained larval zebrafish. The assay involves a closed-loop environment in which the visual feedback a larva receives depends on its own motor output in a way that resembles freely swimming conditions. The experimenter can control the gain of this closed feedback loop, so that following a given motor output the larva experiences more or less visual feedback depending on whether the gain is high or low. We show that increases and decreases in this gain setting result in adaptive changes in behavior that lead to a generalized decrease or increase of motor output, respectively. Our behavioral analysis shows that both the duration and tail beat frequency of individual swim bouts can be modified, as well as the frequency with which bouts are elicited. These changes can be implemented rapidly, following an exposure to a new gain of just 175 ms. In addition, modifications in some behavioral parameters accumulate over tens of seconds and effects last for at least 30 s from trial to trial. These results suggest that larvae establish an internal representation of the visual feedback expected from a given motor output and that the behavioral modifications are driven by an error signal that arises from the discrepancy between this expectation and the actual visual feedback. The assay we develop presents a unique possibility for studying visuomotor integration using imaging techniques available in the larval zebrafish.

Left-handers show no self-advantage in detecting a delay in visual feedback concerning an active movement.

PubMed

Hoover, Adria E N; Elzein, Yasmeenah; Harris, Laurence R

2016-07-01

Right-handed people show an advantage in detecting a delay in visual feedback concerning an active movement of their right hand when it is viewed in a natural perspective compared to when it is seen as if viewing another person's hand (Hoover and Harris in Exp Brain Res 233:1053-1060, 2012. doi: 10.1007/s00221-014-4181-9 ; Exp Brain Res 222:389-397, 2015a. doi: 10.1007/s00221-012-3224-3 ). This self-advantage is unique to their dominant hand and may reflect an enhanced sense of ownership which contributes to how right-handed people relate to the world. Here we asked whether left-handers show the same pattern of performance for their dominant hand. We measured the minimum delay that could be detected by 29 left-handers when viewing either their dominant or non-dominant hand from 'self' or 'other' perspectives and compared their thresholds to an age-matched sample of 22 right-handers. Right-handers showed a significant signature self-advantage of 19 ms when viewing their dominant hand in an expected 'self' perspective compared to 'other' perspectives. Left-handers, however, showed no such advantage for either their dominant or non-dominant hand. This lack of self-advantage in detecting delayed visual feedback might indicate a less secure sense of body ownership amongst left-handers.

Funny money: the attentional role of monetary feedback detached from expected value.

PubMed

Roper, Zachary J J; Vecera, Shaun P

2016-10-01

Stimuli associated with monetary reward can become powerful cues that effectively capture visual attention. We examined whether such value-driven attentional capture can be induced with monetary feedback in the absence of an expected cash payout. To this end, we implemented images of U.S. dollar bills as reward feedback. Participants knew in advance that they would not receive any money based on their performance. Our reward stimuli-$5 and $20 bill images-were thus dissociated from any practical utility. Strikingly, we observed a reliable attentional capture effect for the mere images of bills. Moreover, this finding generalized to Monopoly money. In two control experiments, we found no evidence in favor of nominal or symbolic monetary value. Hence, we claim that bill images are special monetary representations, such that there are strong associations between the defining visual features of bills and reward, probably due to a lifelong learning history. Together, we show that the motivation to earn cash plays a minor role when it comes to monetary rewards, while bill-defining visual features seem to be sufficient. These findings have the potential to influence human factor applications, such as gamification, and can be extended to novel value systems, such as the electronic cash Bitcoin being developed for use in mobile banking. Finally, our procedure represents a proof of concept on how images of money can be used to conserve expenditures in the experimental context.

Feedforward and Feedback Motor Control Abnormalities Implicate Cerebellar Dysfunctions in Autism Spectrum Disorder

PubMed Central

Mohanty, Suman; Greene, Rachel K.; Cook, Edwin H.; Vaillancourt, David E.; Sweeney, John A.

2015-01-01

Sensorimotor abnormalities are common in autism spectrum disorder (ASD) and among the earliest manifestations of the disorder. They have been studied far less than the social-communication and cognitive deficits that define ASD, but a mechanistic understanding of sensorimotor abnormalities in ASD may provide key insights into the neural underpinnings of the disorder. In this human study, we examined rapid, precision grip force contractions to determine whether feedforward mechanisms supporting initial motor output before sensory feedback can be processed are disrupted in ASD. Sustained force contractions also were examined to determine whether reactive adjustments to ongoing motor behavior based on visual feedback are altered. Sustained force was studied across multiple force levels and visual gains to assess motor and visuomotor mechanisms, respectively. Primary force contractions of individuals with ASD showed greater peak rate of force increases and large transient overshoots. Individuals with ASD also showed increased sustained force variability that scaled with force level and was more severe when visual gain was highly amplified or highly degraded. When sustaining a constant force level, their reactive adjustments were more periodic than controls, and they showed increased reliance on slower feedback mechanisms. Feedforward and feedback mechanism alterations each were associated with more severe social-communication impairments in ASD. These findings implicate anterior cerebellar circuits involved in feedforward motor control and posterior cerebellar circuits involved in transforming visual feedback into precise motor adjustments in ASD. PMID:25653359

Context-sensitivity of the feedback-related negativity for zero-value feedback outcomes.

PubMed

Pfabigan, Daniela M; Seidel, Eva-Maria; Paul, Katharina; Grahl, Arvina; Sailer, Uta; Lanzenberger, Rupert; Windischberger, Christian; Lamm, Claus

2015-01-01

The present study investigated whether the same visual stimulus indicating zero-value feedback (€0) elicits feedback-related negativity (FRN) variation, depending on whether the outcomes correspond with expectations or not. Thirty-one volunteers performed a monetary incentive delay (MID) task while EEG was recorded. FRN amplitudes were comparable and more negative when zero-value outcome deviated from expectations than with expected gain or loss, supporting theories emphasising the impact of unexpectedness and salience on FRN amplitudes. Surprisingly, expected zero-value outcomes elicited the most negative FRNs. However, source localisation showed that such outcomes evoked less activation in cingulate areas than unexpected zero-value outcomes. Our study illustrates the context dependency of identical zero-value feedback stimuli. Moreover, the results indicate that the incentive cues in the MID task evoke different reward prediction error signals. These prediction signals differ in FRN amplitude and neuronal sources, and have to be considered in the design and interpretation of future studies. Copyright © 2014 Elsevier B.V. All rights reserved.

Implementation of a six-degree-of-freedom manual controller with passive force feedback

NASA Astrophysics Data System (ADS)

Will, Carol C.; Crane, Carl D., III; Adsit, Phillip

1995-12-01

Force reflective controllers can be divided into two classes; active and passive with the most common being active. Active force-feedback controllers are prone to self-actuation which can generate unintended commands and may injure the user. A six-degree-of-freedom positional input device was designed and constructed that was capable of providing force-feedback passively through the use of six magnetic hysteresis brakes. Special hardware and control strategies were developed to account for some of the limitations of a passive system and the characteristics of hysteresis brakes. The force-feedback input device has been interfaced to a six-degree-of-freedom robot to perform a variety of tasks. Initial research was conducted with a peg-in-hole task. Future research is to include contour following and bead-on-wire tests. Initial results indicated that force-feedback may only be an improvement in situations where visual cues are not clear, and may actually be a hindrance when a clear line of sight exists.

Behavioral Vision Training for Myopia: Stimulus Specificity of Training Effects.

ERIC Educational Resources Information Center

Leung, Jin-Pang

1988-01-01

The study assessed transfer of visual training for myopia using two different training stimuli and a single subject A-B-C-A design with a male student volunteer. A procedure including stimulus fading and reinforcement (positive verbal feedback) was used to effectively improve performance on both behavioral acuity tests during the training phases…

Early Huntington's Disease Affects Movements in Transformed Sensorimotor Mappings

ERIC Educational Resources Information Center

Boulet, C.; Lemay, M.; Bedard, M.A.; Chouinard, M.J.; Chouinard, S.; Richer, F.

2005-01-01

This study examined the effect of transformed visual feedback on movement control in Huntington's disease (HD). Patients in the early stages of HD and controls performed aiming movements towards peripheral targets on a digitizing tablet and emphasizing precision. In a baseline condition, HD patients were slower but showed few precision problems in…

Event-Related fMRI of Category Learning: Differences in Classification and Feedback Networks

ERIC Educational Resources Information Center

Little, Deborah M.; Shin, Silvia S.; Sisco, Shannon M.; Thulborn, Keith R.

2006-01-01

Eighteen healthy young adults underwent event-related (ER) functional magnetic resonance imaging (fMRI) of the brain while performing a visual category learning task. The specific category learning task required subjects to extract the rules that guide classification of quasi-random patterns of dots into categories. Following each classification…

Sex-Role Learning: A Test of the Selective Attention Hypothesis

ERIC Educational Resources Information Center

Bryan, Janice Westlund; Luria, Zella

1978-01-01

Describes 2 experiments in which children ages 5-6 and 9-10 years viewed slides of male and female models performing matched acts which were sex-appropriate, sex-inappropriate, or sex-neutral. Visual attention was assessed by the method of feedback electroencephalography. Recall and preference for the slides were also measured. (Author/JMB)

Runtime visualization of the human arterial tree.

PubMed

Insley, Joseph A; Papka, Michael E; Dong, Suchuan; Karniadakis, George; Karonis, Nicholas T

2007-01-01

Large-scale simulation codes typically execute for extended periods of time and often on distributed computational resources. Because these simulations can run for hours, or even days, scientists like to get feedback about the state of the computation and the validity of its results as it runs. It is also important that these capabilities be made available with little impact on the performance and stability of the simulation. Visualizing and exploring data in the early stages of the simulation can help scientists identify problems early, potentially avoiding a situation where a simulation runs for several days, only to discover that an error with an input parameter caused both time and resources to be wasted. We describe an application that aids in the monitoring and analysis of a simulation of the human arterial tree. The application provides researchers with high-level feedback about the state of the ongoing simulation and enables them to investigate particular areas of interest in greater detail. The application also offers monitoring information about the amount of data produced and data transfer performance among the various components of the application.

A miniature cable-driven robot for crawling on the heart.

PubMed

Patronik, N A; Zenati, M A; Riviere, C N

2005-01-01

This document describes the design and preliminary testing of a cable-driven robot for the purpose of traveling on the surface of the beating heart to administer therapy. This methodology obviates mechanical stabilization and lung deflation, which are typically required during minimally invasive cardiac surgery. Previous versions of the robot have been remotely actuated through push-pull wires, while visual feedback was provided by fiber optic transmission. Although these early models were able to perform locomotion in vivo on porcine hearts, the stiffness of the wire-driven transmission and fiber optic camera limited the mobility of the robots. The new prototype described in this document is actuated by two antagonistic cable pairs, and contains a color CCD camera located in the front section of the device. These modifications have resulted in superior mobility and visual feedback. The cable-driven prototype has successfully demonstrated prehension, locomotion, and tissue dye injection during in vitro testing with a poultry model.

Wrist Camera Orientation for Effective Telerobotic Orbital Replaceable Unit (ORU) Changeout

NASA Technical Reports Server (NTRS)

Jones, Sharon Monica; Aldridge, Hal A.; Vazquez, Sixto L.

1997-01-01

The Hydraulic Manipulator Testbed (HMTB) is the kinematic replica of the Flight Telerobotic Servicer (FTS). One use of the HMTB is to evaluate advanced control techniques for accomplishing robotic maintenance tasks on board the Space Station. Most maintenance tasks involve the direct manipulation of the robot by a human operator when high-quality visual feedback is important for precise control. An experiment was conducted in the Systems Integration Branch at the Langley Research Center to compare several configurations of the manipulator wrist camera for providing visual feedback during an Orbital Replaceable Unit changeout task. Several variables were considered such as wrist camera angle, camera focal length, target location, lighting. Each study participant performed the maintenance task by using eight combinations of the variables based on a Latin square design. The results of this experiment and conclusions based on data collected are presented.

Integrative Advances for OCT-Guided Ophthalmic Surgery and Intraoperative OCT: Microscope Integration, Surgical Instrumentation, and Heads-Up Display Surgeon Feedback

PubMed Central

Ehlers, Justis P.; Srivastava, Sunil K.; Feiler, Daniel; Noonan, Amanda I.; Rollins, Andrew M.; Tao, Yuankai K.

2014-01-01

Purpose To demonstrate key integrative advances in microscope-integrated intraoperative optical coherence tomography (iOCT) technology that will facilitate adoption and utilization during ophthalmic surgery. Methods We developed a second-generation prototype microscope-integrated iOCT system that interfaces directly with a standard ophthalmic surgical microscope. Novel features for improved design and functionality included improved profile and ergonomics, as well as a tunable lens system for optimized image quality and heads-up display (HUD) system for surgeon feedback. Novel material testing was performed for potential suitability for OCT-compatible instrumentation based on light scattering and transmission characteristics. Prototype surgical instruments were developed based on material testing and tested using the microscope-integrated iOCT system. Several surgical maneuvers were performed and imaged, and surgical motion visualization was evaluated with a unique scanning and image processing protocol. Results High-resolution images were successfully obtained with the microscope-integrated iOCT system with HUD feedback. Six semi-transparent materials were characterized to determine their attenuation coefficients and scatter density with an 830 nm OCT light source. Based on these optical properties, polycarbonate was selected as a material substrate for prototype instrument construction. A surgical pick, retinal forceps, and corneal needle were constructed with semi-transparent materials. Excellent visualization of both the underlying tissues and surgical instrument were achieved on OCT cross-section. Using model eyes, various surgical maneuvers were visualized, including membrane peeling, vessel manipulation, cannulation of the subretinal space, subretinal intraocular foreign body removal, and corneal penetration. Conclusions Significant iterative improvements in integrative technology related to iOCT and ophthalmic surgery are demonstrated. PMID:25141340

Investigating the Prospective Sense of Agency: Effects of Processing Fluency, Stimulus Ambiguity, and Response Conflict.

PubMed

Sidarus, Nura; Vuorre, Matti; Metcalfe, Janet; Haggard, Patrick

2017-01-01

How do we know how much control we have over our environment? The sense of agency refers to the feeling that we are in control of our actions, and that, through them, we can control our external environment. Thus, agency clearly involves matching intentions, actions, and outcomes. The present studies investigated the possibility that processes of action selection, i.e., choosing what action to make, contribute to the sense of agency. Since selection of action necessarily precedes execution of action, such effects must be prospective. In contrast, most literature on sense of agency has focussed on the retrospective computation whether an outcome fits the action performed or intended. This hypothesis was tested in an ecologically rich, dynamic task based on a computer game. Across three experiments, we manipulated three different aspects of action selection processing: visual processing fluency, categorization ambiguity, and response conflict. Additionally, we measured the relative contributions of prospective, action selection-based cues, and retrospective, outcome-based cues to the sense of agency. Manipulations of action selection were orthogonally combined with discrepancy of visual feedback of action. Fluency of action selection had a small but reliable effect on the sense of agency. Additionally, as expected, sense of agency was strongly reduced when visual feedback was discrepant with the action performed. The effects of discrepant feedback were larger than the effects of action selection fluency, and sometimes suppressed them. The sense of agency is highly sensitive to disruptions of action-outcome relations. However, when motor control is successful, and action-outcome relations are as predicted, fluency or dysfluency of action selection provides an important prospective cue to the sense of agency.

Investigating the Prospective Sense of Agency: Effects of Processing Fluency, Stimulus Ambiguity, and Response Conflict

PubMed Central

Sidarus, Nura; Vuorre, Matti; Metcalfe, Janet; Haggard, Patrick

2017-01-01

How do we know how much control we have over our environment? The sense of agency refers to the feeling that we are in control of our actions, and that, through them, we can control our external environment. Thus, agency clearly involves matching intentions, actions, and outcomes. The present studies investigated the possibility that processes of action selection, i.e., choosing what action to make, contribute to the sense of agency. Since selection of action necessarily precedes execution of action, such effects must be prospective. In contrast, most literature on sense of agency has focussed on the retrospective computation whether an outcome fits the action performed or intended. This hypothesis was tested in an ecologically rich, dynamic task based on a computer game. Across three experiments, we manipulated three different aspects of action selection processing: visual processing fluency, categorization ambiguity, and response conflict. Additionally, we measured the relative contributions of prospective, action selection-based cues, and retrospective, outcome-based cues to the sense of agency. Manipulations of action selection were orthogonally combined with discrepancy of visual feedback of action. Fluency of action selection had a small but reliable effect on the sense of agency. Additionally, as expected, sense of agency was strongly reduced when visual feedback was discrepant with the action performed. The effects of discrepant feedback were larger than the effects of action selection fluency, and sometimes suppressed them. The sense of agency is highly sensitive to disruptions of action-outcome relations. However, when motor control is successful, and action-outcome relations are as predicted, fluency or dysfluency of action selection provides an important prospective cue to the sense of agency. PMID:28450839

Finger force changes in the absence of visual feedback in patients with Parkinson’s disease

PubMed Central

Jo, Hang Jin; Ambike, Satyajit; Lewis, Mechelle M.; Huang, Xuemei; Latash, Mark L.

2015-01-01

Objectives We investigated the unintentional drift in total force and in sharing of the force between fingers in two-finger accurate force production tasks performed without visual feedback by patients with Parkinson’s disease (PD) and healthy controls. In particular, we were testing a hypothesis that adaptation to the documented loss of action stability could lead to faster force drop in PD. Methods PD patients and healthy controls performed accurate constant force production tasks without visual feedback by different finger pairs, starting with different force levels and different sharing patterns of force between the two fingers. Results Both groups showed an exponential force drop with time and a drift of the sharing pattern towards 50:50. The PD group showed a significantly faster force drop without a change in speed of the sharing drift. These results were consistent across initial force levels, sharing patterns, and finger pairs. A pilot test of four subjects, two PD and two controls, showed no consistent effects of memory on the force drop. Conclusions We interpret the force drop as a consequence of back-coupling between the actual and referent finger coordinates that draws the referent coordinate towards the actual one. The faster force drop in the PD group is interpreted as adaptive to the loss of action stability in PD. The lack of group differences in the sharing drift suggests two potentially independent physiological mechanisms contributing to the force and sharing drifts. Significance The hypothesis on adaptive changes in PD with the purpose to ensure stability of steady states may have important implications for treatment of PD. The speed of force drop may turn into a useful tool to quantify such adaptive changes. PMID:26072437

A Physics-Based Vibrotactile Feedback Library for Collision Events.

PubMed

Park, Gunhyuk; Choi, Seungmoon

2017-01-01

We present PhysVib: a software solution on the mobile platform extending an open-source physics engine in a multi-rate rendering architecture for automatic vibrotactile feedback upon collision events. PhysVib runs concurrently with a physics engine at a low update rate and generates vibrotactile feedback commands at a high update rate based on the simulation results of the physics engine using an exponentially-decaying sinusoidal model. We demonstrate through a user study that this vibration model is more appropriate to our purpose in terms of perceptual quality than more complex models based on sound synthesis. We also evaluated the perceptual performance of PhysVib by comparing eight vibrotactile rendering methods. Experimental results suggested that PhysVib enables more realistic vibrotactile feedback than the other methods as to perceived similarity to the visual events. PhysVib is an effective solution for providing physically plausible vibrotactile responses while reducing application development time to great extent.

Using Screencasts to Enhance Assessment Feedback: Students' Perceptions and Preferences

ERIC Educational Resources Information Center

Marriott, Pru; Teoh, Lim Keong

2012-01-01

In the UK, assessment and feedback have been regularly highlighted by the National Student Survey as critical aspects that require improvement. An innovative approach to delivering feedback that has proved successful in non-business-related disciplines is the delivery of audio and visual feedback using screencast technology. The feedback on…

Is the use of videotape recording superior to verbal feedback alone in the teaching of clinical skills?

PubMed Central

2009-01-01

Background In recent times, medical schools have committed to developing good communication and history taking skills in students. However, there remains an unresolved question as to which constitutes the best educational method. Our study aims to investigate whether the use of videotape recording is superior to verbal feedback alone in the teaching of clinical skills and the role of student self-assessment on history taking and communication skills. Methods A randomized controlled trial was designed. The study was conducted with 52 of the Dokuz Eylul University Faculty of Medicine second year students. All students' performances of communication and history taking skills were assessed twice. Between these assessments, the study group had received both verbal and visual feedback by watching their video recordings on patient interview; the control group received only verbal feedback from the teacher. Results Although the self-assessment of the students did not change significantly, assessors' ratings increased significantly for videotaped interviews at the second time. Conclusions Feedback based on videotaped interviews is superior to the feedback given solely based on the observation of assessors. PMID:20021688

Is the use of videotape recording superior to verbal feedback alone in the teaching of clinical skills?

PubMed

Ozcakar, Nilgun; Mevsim, Vildan; Guldal, Dilek; Gunvar, Tolga; Yildirim, Ediz; Sisli, Zafer; Semin, Ilgi

2009-12-19

In recent times, medical schools have committed to developing good communication and history taking skills in students. However, there remains an unresolved question as to which constitutes the best educational method. Our study aims to investigate whether the use of videotape recording is superior to verbal feedback alone in the teaching of clinical skills and the role of student self-assessment on history taking and communication skills. A randomized controlled trial was designed. The study was conducted with 52 of the Dokuz Eylul University Faculty of Medicine second year students. All students' performances of communication and history taking skills were assessed twice. Between these assessments, the study group had received both verbal and visual feedback by watching their video recordings on patient interview; the control group received only verbal feedback from the teacher. Although the self-assessment of the students did not change significantly, assessors' ratings increased significantly for videotaped interviews at the second time. Feedback based on videotaped interviews is superior to the feedback given solely based on the observation of assessors.

Reward abundance interferes with error-based learning in a visuomotor adaptation task

PubMed Central

Oostwoud Wijdenes, Leonie; Rigterink, Tessa; Overvliet, Krista E.; Smeets, Joeren B. J.

2018-01-01

The brain rapidly adapts reaching movements to changing circumstances by using visual feedback about errors. Providing reward in addition to error feedback facilitates the adaptation but the underlying mechanism is unknown. Here, we investigate whether the proportion of trials rewarded (the ‘reward abundance’) influences how much participants adapt to their errors. We used a 3D multi-target pointing task in which reward alone is insufficient for motor adaptation. Participants (N = 423) performed the pointing task with feedback based on a shifted hand-position. On a proportion of trials we gave them rewarding feedback that their hand hit the target. Half of the participants only received this reward feedback. The other half also received feedback about endpoint errors. In different groups, we varied the proportion of trials that was rewarded. As expected, participants who received feedback about their errors did adapt, but participants who only received reward-feedback did not. Critically, participants who received abundant rewards adapted less to their errors than participants who received less reward. Thus, reward abundance negatively influences how much participants learn from their errors. Probably participants used a mechanism that relied more on the reward feedback when the reward was abundant. Because participants could not adapt to the reward, this interfered with adaptation to errors. PMID:29513681

Writing in the Air: Contributions of Finger Movement to Cognitive Processing

PubMed Central

Itaguchi, Yoshihiro; Yamada, Chiharu; Fukuzawa, Kazuyoshi

2015-01-01

The present study investigated the interactions between motor action and cognitive processing with particular reference to kanji-culture individuals. Kanji-culture individuals often move their finger as if they are writing when they are solving cognitive tasks, for example, when they try to recall the spelling of English words. This behavior is called kusho, meaning air-writing in Japanese. However, its functional role is still unknown. To reveal the role of kusho behavior in cognitive processing, we conducted a series of experiments, employing two different cognitive tasks, a construction task and a stroke count task. To distinguish the effects of the kinetic aspects of kusho behavior, we set three hand conditions in the tasks; participants were instructed to use either kusho, unrelated finger movements or do nothing during the response time. To isolate possible visual effects, two visual conditions in which participants saw their hand and the other in which they did not, were introduced. We used the number of correct responses and response time as measures of the task performance. The results showed that kusho behavior has different functional roles in the two types of cognitive tasks. In the construction task, the visual feedback from finger movement facilitated identifying a character, whereas the kinetic feedback or motor commands for the behavior did not help to solve the task. In the stroke count task, by contrast, the kinetic aspects of the finger movements influenced counting performance depending on the type of the finger movement. Regardless of the visual condition, kusho behavior improved task performance and unrelated finger movements degraded it. These results indicated that motor behavior contributes to cognitive processes. We discussed possible mechanisms of the modality dependent contribution. These findings might lead to better understanding of the complex interaction between action and cognition in daily life. PMID:26061273

Writing in the Air: Contributions of Finger Movement to Cognitive Processing.

PubMed

Itaguchi, Yoshihiro; Yamada, Chiharu; Fukuzawa, Kazuyoshi

2015-01-01

The present study investigated the interactions between motor action and cognitive processing with particular reference to kanji-culture individuals. Kanji-culture individuals often move their finger as if they are writing when they are solving cognitive tasks, for example, when they try to recall the spelling of English words. This behavior is called kusho, meaning air-writing in Japanese. However, its functional role is still unknown. To reveal the role of kusho behavior in cognitive processing, we conducted a series of experiments, employing two different cognitive tasks, a construction task and a stroke count task. To distinguish the effects of the kinetic aspects of kusho behavior, we set three hand conditions in the tasks; participants were instructed to use either kusho, unrelated finger movements or do nothing during the response time. To isolate possible visual effects, two visual conditions in which participants saw their hand and the other in which they did not, were introduced. We used the number of correct responses and response time as measures of the task performance. The results showed that kusho behavior has different functional roles in the two types of cognitive tasks. In the construction task, the visual feedback from finger movement facilitated identifying a character, whereas the kinetic feedback or motor commands for the behavior did not help to solve the task. In the stroke count task, by contrast, the kinetic aspects of the finger movements influenced counting performance depending on the type of the finger movement. Regardless of the visual condition, kusho behavior improved task performance and unrelated finger movements degraded it. These results indicated that motor behavior contributes to cognitive processes. We discussed possible mechanisms of the modality dependent contribution. These findings might lead to better understanding of the complex interaction between action and cognition in daily life.

Designing between Pedagogies and Cultures: Audio-Visual Chinese Language Resources for Australian Schools

ERIC Educational Resources Information Center

Yuan, Yifeng; Shen, Huizhong

2016-01-01

This design-based study examines the creation and development of audio-visual Chinese language teaching and learning materials for Australian schools by incorporating users' feedback and content writers' input that emerged in the designing process. Data were collected from workshop feedback of two groups of Chinese-language teachers from primary…

Using Real-Time Visual Feedback to Improve Posture at Computer Workstations

ERIC Educational Resources Information Center

Sigurdsson, Sigurdur O.; Austin, John

2008-01-01

The purpose of the current study was to examine the effects of a multicomponent intervention that included discrimination training, real-time visual feedback, and self-monitoring on postural behavior at a computer workstation in a simulated office environment. Using a nonconcurrent multiple baseline design across 8 participants, the study assessed…

Facilitating Learning from Animated Instruction: Effectiveness of Questions and Feedback as Attention-Directing Strategies

ERIC Educational Resources Information Center

Lin, Huifen

2011-01-01

The purpose of this study was to investigate the relative effectiveness of different types of visuals (static and animated) and instructional strategies (no strategy, questions, and questions plus feedback) used to complement visualized materials on students' learning of different educational objectives in a computer-based instructional (CBI)…

Reward Selectively Modulates the Lingering Neural Representation of Recently Attended Objects in Natural Scenes.

PubMed

Hickey, Clayton; Peelen, Marius V

2017-08-02

Theories of reinforcement learning and approach behavior suggest that reward can increase the perceptual salience of environmental stimuli, ensuring that potential predictors of outcome are noticed in the future. However, outcome commonly follows visual processing of the environment, occurring even when potential reward cues have long disappeared. How can reward feedback retroactively cause now-absent stimuli to become attention-drawing in the future? One possibility is that reward and attention interact to prime lingering visual representations of attended stimuli that sustain through the interval separating stimulus and outcome. Here, we test this idea using multivariate pattern analysis of fMRI data collected from male and female humans. While in the scanner, participants searched for examples of target categories in briefly presented pictures of cityscapes and landscapes. Correct task performance was followed by reward feedback that could randomly have either high or low magnitude. Analysis showed that high-magnitude reward feedback boosted the lingering representation of target categories while reducing the representation of nontarget categories. The magnitude of this effect in each participant predicted the behavioral impact of reward on search performance in subsequent trials. Other analyses show that sensitivity to reward-as expressed in a personality questionnaire and in reactivity to reward feedback in the dopaminergic midbrain-predicted reward-elicited variance in lingering target and nontarget representations. Credit for rewarding outcome thus appears to be assigned to the target representation, causing the visual system to become sensitized for similar objects in the future. SIGNIFICANCE STATEMENT How do reward-predictive visual stimuli become salient and attention-drawing? In the real world, reward cues precede outcome and reward is commonly received long after potential predictors have disappeared. How can the representation of environmental stimuli be affected by outcome that occurs later in time? Here, we show that reward acts on lingering representations of environmental stimuli that sustain through the interval between stimulus and outcome. Using naturalistic scene stimuli and multivariate pattern analysis of fMRI data, we show that reward boosts the representation of attended objects and reduces the representation of unattended objects. This interaction of attention and reward processing acts to prime vision for stimuli that may serve to predict outcome. Copyright © 2017 the authors 0270-6474/17/377297-08$15.00/0.

Perception of CPR quality: Influence of CPR feedback, Just-in-Time CPR training and provider role.

PubMed

Cheng, Adam; Overly, Frank; Kessler, David; Nadkarni, Vinay M; Lin, Yiqun; Doan, Quynh; Duff, Jonathan P; Tofil, Nancy M; Bhanji, Farhan; Adler, Mark; Charnovich, Alex; Hunt, Elizabeth A; Brown, Linda L

2015-02-01

Many healthcare providers rely on visual perception to guide cardiopulmonary resuscitation (CPR), but little is known about the accuracy of provider perceptions of CPR quality. We aimed to describe the difference between perceived versus measured CPR quality, and to determine the impact of provider role, real-time visual CPR feedback and Just-in-Time (JIT) CPR training on provider perceptions. We conducted secondary analyses of data collected from a prospective, multicenter, randomized trial of 324 healthcare providers who participated in a simulated cardiac arrest scenario between July 2012 and April 2014. Participants were randomized to one of four permutations of: JIT CPR training and real-time visual CPR feedback. We calculated the difference between perceived and measured quality of CPR and reported the proportion of subjects accurately estimating the quality of CPR within each study arm. Participants overestimated achieving adequate chest compression depth (mean difference range: 16.1-60.6%) and rate (range: 0.2-51%), and underestimated chest compression fraction (0.2-2.9%) across all arms. Compared to no intervention, the use of real-time feedback and JIT CPR training (alone or in combination) improved perception of depth (p<0.001). Accurate estimation of CPR quality was poor for chest compression depth (0-13%), rate (5-46%) and chest compression fraction (60-63%). Perception of depth is more accurate in CPR providers versus team leaders (27.8% vs. 7.4%; p=0.043) when using real-time feedback. Healthcare providers' visual perception of CPR quality is poor. Perceptions of CPR depth are improved by using real-time visual feedback and with prior JIT CPR training. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Foot placement relies on state estimation during visually guided walking.

PubMed

Maeda, Rodrigo S; O'Connor, Shawn M; Donelan, J Maxwell; Marigold, Daniel S

2017-02-01

As we walk, we must accurately place our feet to stabilize our motion and to navigate our environment. We must also achieve this accuracy despite imperfect sensory feedback and unexpected disturbances. In this study we tested whether the nervous system uses state estimation to beneficially combine sensory feedback with forward model predictions to compensate for these challenges. Specifically, subjects wore prism lenses during a visually guided walking task, and we used trial-by-trial variation in prism lenses to add uncertainty to visual feedback and induce a reweighting of this input. To expose altered weighting, we added a consistent prism shift that required subjects to adapt their estimate of the visuomotor mapping relationship between a perceived target location and the motor command necessary to step to that position. With added prism noise, subjects responded to the consistent prism shift with smaller initial foot placement error but took longer to adapt, compatible with our mathematical model of the walking task that leverages state estimation to compensate for noise. Much like when we perform voluntary and discrete movements with our arms, it appears our nervous systems uses state estimation during walking to accurately reach our foot to the ground. Accurate foot placement is essential for safe walking. We used computational models and human walking experiments to test how our nervous system achieves this accuracy. We find that our control of foot placement beneficially combines sensory feedback with internal forward model predictions to accurately estimate the body's state. Our results match recent computational neuroscience findings for reaching movements, suggesting that state estimation is a general mechanism of human motor control. Copyright © 2017 the American Physiological Society.

Data-Driven User Feedback: An Improved Neurofeedback Strategy considering the Interindividual Variability of EEG Features.

PubMed

Han, Chang-Hee; Lim, Jeong-Hwan; Lee, Jun-Hak; Kim, Kangsan; Im, Chang-Hwan

2016-01-01

It has frequently been reported that some users of conventional neurofeedback systems can experience only a small portion of the total feedback range due to the large interindividual variability of EEG features. In this study, we proposed a data-driven neurofeedback strategy considering the individual variability of electroencephalography (EEG) features to permit users of the neurofeedback system to experience a wider range of auditory or visual feedback without a customization process. The main idea of the proposed strategy is to adjust the ranges of each feedback level using the density in the offline EEG database acquired from a group of individuals. Twenty-two healthy subjects participated in offline experiments to construct an EEG database, and five subjects participated in online experiments to validate the performance of the proposed data-driven user feedback strategy. Using the optimized bin sizes, the number of feedback levels that each individual experienced was significantly increased to 139% and 144% of the original results with uniform bin sizes in the offline and online experiments, respectively. Our results demonstrated that the use of our data-driven neurofeedback strategy could effectively increase the overall range of feedback levels that each individual experienced during neurofeedback training.

Data-Driven User Feedback: An Improved Neurofeedback Strategy considering the Interindividual Variability of EEG Features

PubMed Central

Lim, Jeong-Hwan; Lee, Jun-Hak; Kim, Kangsan

2016-01-01

It has frequently been reported that some users of conventional neurofeedback systems can experience only a small portion of the total feedback range due to the large interindividual variability of EEG features. In this study, we proposed a data-driven neurofeedback strategy considering the individual variability of electroencephalography (EEG) features to permit users of the neurofeedback system to experience a wider range of auditory or visual feedback without a customization process. The main idea of the proposed strategy is to adjust the ranges of each feedback level using the density in the offline EEG database acquired from a group of individuals. Twenty-two healthy subjects participated in offline experiments to construct an EEG database, and five subjects participated in online experiments to validate the performance of the proposed data-driven user feedback strategy. Using the optimized bin sizes, the number of feedback levels that each individual experienced was significantly increased to 139% and 144% of the original results with uniform bin sizes in the offline and online experiments, respectively. Our results demonstrated that the use of our data-driven neurofeedback strategy could effectively increase the overall range of feedback levels that each individual experienced during neurofeedback training. PMID:27631005

The impact of haptic feedback on students' conceptions of the cell

NASA Astrophysics Data System (ADS)

Minogue, James

2005-07-01

The purpose of this study was to investigate the efficacy of adding haptic (sense of touch) feedback to computer generated visualizations for use in middle school science instruction. Current technology allows for the simulation of tactile and kinesthetic sensations via haptic devices and a computer interface. This study, conducted with middle school students (n = 80), explored the cognitive and affective impacts of this innovative technology on students' conceptions of the cell and the process of passive transport. A pretest-posttest control group design was used and participants were randomly assigned to one of two treatment groups (n = 40 for each). Both groups experienced the same core computer-mediated instructional program. This Cell Exploration program engaged students in a 3-D immersive environment that allowed them to actively investigate the form and function of a typical animal cell including its major organelles. The program also engaged students in a study of the structure and function of the cell membrane as it pertains to the process of passive transport and the mechanisms behind the membrane's selective permeability. As they conducted their investigations, students in the experimental group received bi-modal visual and haptic (simulated tactile and kinesthetic) feedback whereas the control group students experienced the program with only visual stimuli. A battery of assessments, including objective and open-ended written response items as well as a haptic performance assessment, were used to gather quantitative and qualitative data regarding changes in students' understandings of the cell concepts prior to and following their completion of the instructional program. Additionally, the impact of haptics on the affective domain of students' learning was assessed using a post-experience semi-structured interview and an attitudinal survey. Results showed that students from both conditions (Visual-Only and Visual + Haptic) found the instructional program interesting and engaging. Additionally, the vast majority of the students reported that they learned a lot about and were more interested in the topic due to their participation. Moreover, students who received the bi-modal (Visual + Haptic) feedback indicated that they experienced lower levels of frustration and spatial disorientation as they conducted their investigations when compared to individuals that relied solely on vision. There were no significant differences measured across the treatment groups on the cognitive assessment items. Despite this finding, the study provided valuable insight into the theoretical and practical considerations involved in the development of multimodal instructional programs.

3D visualization of movements can amplify motor cortex activation during subsequent motor imagery

PubMed Central

Sollfrank, Teresa; Hart, Daniel; Goodsell, Rachel; Foster, Jonathan; Tan, Tele

2015-01-01

A repetitive movement practice by motor imagery (MI) can influence motor cortical excitability in the electroencephalogram (EEG). This study investigated if a realistic visualization in 3D of upper and lower limb movements can amplify motor related potentials during subsequent MI. We hypothesized that a richer sensory visualization might be more effective during instrumental conditioning, resulting in a more pronounced event related desynchronization (ERD) of the upper alpha band (10–12 Hz) over the sensorimotor cortices thereby potentially improving MI based brain-computer interface (BCI) protocols for motor rehabilitation. The results show a strong increase of the characteristic patterns of ERD of the upper alpha band components for left and right limb MI present over the sensorimotor areas in both visualization conditions. Overall, significant differences were observed as a function of visualization modality (VM; 2D vs. 3D). The largest upper alpha band power decrease was obtained during MI after a 3-dimensional visualization. In total in 12 out of 20 tasks the end-user of the 3D visualization group showed an enhanced upper alpha ERD relative to 2D VM group, with statistical significance in nine tasks.With a realistic visualization of the limb movements, we tried to increase motor cortex activation during subsequent MI. The feedback and the feedback environment should be inherently motivating and relevant for the learner and should have an appeal of novelty, real-world relevance or aesthetic value (Ryan and Deci, 2000; Merrill, 2007). Realistic visual feedback, consistent with the participant’s MI, might be helpful for accomplishing successful MI and the use of such feedback may assist in making BCI a more natural interface for MI based BCI rehabilitation. PMID:26347642

3D visualization of movements can amplify motor cortex activation during subsequent motor imagery.

PubMed

Sollfrank, Teresa; Hart, Daniel; Goodsell, Rachel; Foster, Jonathan; Tan, Tele

2015-01-01

A repetitive movement practice by motor imagery (MI) can influence motor cortical excitability in the electroencephalogram (EEG). This study investigated if a realistic visualization in 3D of upper and lower limb movements can amplify motor related potentials during subsequent MI. We hypothesized that a richer sensory visualization might be more effective during instrumental conditioning, resulting in a more pronounced event related desynchronization (ERD) of the upper alpha band (10-12 Hz) over the sensorimotor cortices thereby potentially improving MI based brain-computer interface (BCI) protocols for motor rehabilitation. The results show a strong increase of the characteristic patterns of ERD of the upper alpha band components for left and right limb MI present over the sensorimotor areas in both visualization conditions. Overall, significant differences were observed as a function of visualization modality (VM; 2D vs. 3D). The largest upper alpha band power decrease was obtained during MI after a 3-dimensional visualization. In total in 12 out of 20 tasks the end-user of the 3D visualization group showed an enhanced upper alpha ERD relative to 2D VM group, with statistical significance in nine tasks.With a realistic visualization of the limb movements, we tried to increase motor cortex activation during subsequent MI. The feedback and the feedback environment should be inherently motivating and relevant for the learner and should have an appeal of novelty, real-world relevance or aesthetic value (Ryan and Deci, 2000; Merrill, 2007). Realistic visual feedback, consistent with the participant's MI, might be helpful for accomplishing successful MI and the use of such feedback may assist in making BCI a more natural interface for MI based BCI rehabilitation.

Reliability of Visual and Somatosensory Feedback in Skilled Movement: The Role of the Cerebellum.

PubMed

Mizelle, J C; Oparah, Alexis; Wheaton, Lewis A

2016-01-01

The integration of vision and somatosensation is required to allow for accurate motor behavior. While both sensory systems contribute to an understanding of the state of the body through continuous updating and estimation, how the brain processes unreliable sensory information remains to be fully understood in the context of complex action. Using functional brain imaging, we sought to understand the role of the cerebellum in weighting visual and somatosensory feedback by selectively reducing the reliability of each sense individually during a tool use task. We broadly hypothesized upregulated activation of the sensorimotor and cerebellar areas during movement with reduced visual reliability, and upregulated activation of occipital brain areas during movement with reduced somatosensory reliability. As specifically compared to reduced somatosensory reliability, we expected greater activations of ipsilateral sensorimotor cerebellum for intact visual and somatosensory reliability. Further, we expected that ipsilateral posterior cognitive cerebellum would be affected with reduced visual reliability. We observed that reduced visual reliability results in a trend towards the relative consolidation of sensorimotor activation and an expansion of cerebellar activation. In contrast, reduced somatosensory reliability was characterized by the absence of cerebellar activations and a trend towards the increase of right frontal, left parietofrontal activation, and temporo-occipital areas. Our findings highlight the role of the cerebellum for specific aspects of skillful motor performance. This has relevance to understanding basic aspects of brain functions underlying sensorimotor integration, and provides a greater understanding of cerebellar function in tool use motor control.

Analysis of Feedback in after Action Reviews

DTIC Science & Technology

1987-06-01

CONNTSM Page INTRODUCTIUN . . . . . . . . . . . . . . . . . . . A Perspective on Feedback. . ....... • • ..... • 1 Overviev of %,•urrent Research...part of their training program . The AAR is in marked contrast to the critique method of feedback which is often used in military training. The AAR...feedback is task-inherent feedback. Task-inherent feedback refers to human-machine interacting systems, e.g., computers , where in a visual tracking task

Prior history of FDI muscle contraction: different effect on MEP amplitude and muscle activity.

PubMed

Talis, V L; Kazennikov, O V; Castellote, J M; Grishin, A A; Ioffe, M E

2014-03-01

Motor evoked potentials (MEPs) in the right first dorsal interosseous (FDI) muscle elicited by transcranial magnetic stimulation of left motor cortex were assessed in ten healthy subjects during maintenance of a fixed FDI contraction level. Subjects maintained an integrated EMG (IEMG) level with visual feedback and reproduced this level by memory afterwards in the following tasks: stationary FDI muscle contraction at the level of 40 ± 5 % of its maximum voluntary contraction (MVC; 40 % task), at the level of 20 ± 5 % MVC (20 % task), and also when 20 % MVC was preceded by either no contraction (0-20 task), by stronger muscle contraction (40-20 task) or by no contraction with a previous strong contraction (40-0-20 task). The results show that the IEMG level was within the prescribed limits when 20 and 40 % stationary tasks were executed with and without visual feedback. In 0-20, 40-20, and 40-0-20 tasks, 20 % IEMG level was precisely controlled in the presence of visual feedback, but without visual feedback the IEMG and force during 20 % IEMG maintenance were significantly higher in the 40-0-20 task than those in 0-20 and 40-20 tasks. That is, without visual feedback, there were significant variations in muscle activity due to different prehistory of contraction. In stationary tasks, MEP amplitudes in 40 % task were higher than in 20 % task. MEPs did not differ significantly during maintenance of the 20 % level in tasks with different prehistory of muscle contraction with and without visual feedback. Thus, in spite of variations in muscle background activity due to different prehistory of contraction MEPs did not vary significantly. This dissociation suggests that the voluntary maintenance of IEMG level is determined not only by cortical mechanisms, as reflected by corticospinal excitability, but also by lower levels of CNS, where afferent signals and influences from other brain structures and spinal cord are convergent.

Training students with patient actors improves communication: a pilot study.

PubMed

Anderson, Heather A; Young, Jack; Marrelli, Danica; Black, Rudolph; Lambreghts, Kimberly; Twa, Michael D

2014-01-01

Effective patient communication is correlated with better health outcomes and patient satisfaction, but is challenging to train, particularly with difficult clinical scenarios such as loss of sight. In this pilot study, we evaluated the use of simulated patient encounters with actors to train optometric students. Students were recorded during encounters with actors and assigned to an enrichment group performing five interactions with instructor feedback (n = 6) or a no-enrichment group performing two interactions without feedback (n = 4). Student performance on first and last encounters was scored with (1) subjective rating of performance change using a visual analog scale (anchors: much worse/much better), (2) yes/no response: Would you recommend this doctor to a friend/relative?, and (3) average score on questions from the American Board of Internal Medicine (ABIM) assessment of doctor communication skills. Three clinical instructors, masked to student group assignments and the order of patient encounters they viewed, provided scores in addition to self-evaluation by students and patient-actors. Using the visual analog scale, students who received enrichment were rated more improved than the no-enrichment group by masked examiners (+18 vs. -11% p = 0.04) and self-evaluation (+79 vs. +27% p = 0.009), but not by actors (+31 vs. +43%). The proportion of students recommended significantly increased following enrichment for masked examiners (61% vs. 94%; p < 0.001), but not actors (100 vs. 83%). Average ABIM assessment scores were not significantly different by any rating group: masked instructors, actors, or self-ratings. The findings of this study suggest five simulated patient encounters with feedback result in measurable improvement in student-patient communication skills as rated by masked examiners.

Feedforward and feedback motor control abnormalities implicate cerebellar dysfunctions in autism spectrum disorder.

PubMed

Mosconi, Matthew W; Mohanty, Suman; Greene, Rachel K; Cook, Edwin H; Vaillancourt, David E; Sweeney, John A

2015-02-04

Sensorimotor abnormalities are common in autism spectrum disorder (ASD) and among the earliest manifestations of the disorder. They have been studied far less than the social-communication and cognitive deficits that define ASD, but a mechanistic understanding of sensorimotor abnormalities in ASD may provide key insights into the neural underpinnings of the disorder. In this human study, we examined rapid, precision grip force contractions to determine whether feedforward mechanisms supporting initial motor output before sensory feedback can be processed are disrupted in ASD. Sustained force contractions also were examined to determine whether reactive adjustments to ongoing motor behavior based on visual feedback are altered. Sustained force was studied across multiple force levels and visual gains to assess motor and visuomotor mechanisms, respectively. Primary force contractions of individuals with ASD showed greater peak rate of force increases and large transient overshoots. Individuals with ASD also showed increased sustained force variability that scaled with force level and was more severe when visual gain was highly amplified or highly degraded. When sustaining a constant force level, their reactive adjustments were more periodic than controls, and they showed increased reliance on slower feedback mechanisms. Feedforward and feedback mechanism alterations each were associated with more severe social-communication impairments in ASD. These findings implicate anterior cerebellar circuits involved in feedforward motor control and posterior cerebellar circuits involved in transforming visual feedback into precise motor adjustments in ASD. Copyright © 2015 the authors 0270-6474/15/352015-11$15.00/0.

Reduced pressure for fewer pressure ulcers: can real-time feedback of interface pressure optimise repositioning in bed?

PubMed

Gunningberg, Lena; Carli, Cheryl

2016-10-01

The aim of this study was to (i) describe registered nurses' and assistant nurses' repositioning skills with regard to their existing attitudes to and theoretical knowledge of pressure ulcer (PU) prevention, and (ii) evaluate if the continuous bedside pressure mapping (CBPM) system provides staff with a pedagogic tool to optimise repositioning. A quantitative study was performed using a descriptive, comparative design. Registered nurses (n = 19) and assistant nurses (n = 33) worked in pairs, and were instructed to place two volunteers (aged over 70 years) in the best pressure-reducing position (lateral and supine), first without viewing the CBPM monitor and then again after feedback. In total, 240 positionings were conducted. The results show that for the same person with the same available pressure-reducing equipment, the peak pressure varied considerably between nursing pairs. Reducing pressure in the lateral position appeared to be the most challenging. Peak pressures were significantly reduced, based on visual feedback from the CBPM monitor. The number of preventive interventions also increased, as well as patients' comfort. For the nurses as a group, the knowledge score was 59·7% and the attitude score was 88·8%. Real-time visual feedback of pressure points appears to provide another dimension to complement decision making with respect to PU prevention. © 2014 The Authors. International Wound Journal © 2014 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Embodied neurofeedback with an anthropomorphic robotic hand

PubMed Central

Braun, Niclas; Emkes, Reiner; Thorne, Jeremy D.; Debener, Stefan

2016-01-01

Neurofeedback-guided motor imagery training (NF-MIT) has been suggested as a promising therapy for stroke-induced motor impairment. Whereas much NF-MIT research has aimed at signal processing optimization, the type of sensory feedback given to the participant has received less attention. Often the feedback signal is highly abstract and not inherently coupled to the mental act performed. In this study, we asked whether an embodied feedback signal is more efficient for neurofeedback operation than a non-embodiable feedback signal. Inspired by the rubber hand illusion, demonstrating that an artificial hand can be incorporated into one’s own body scheme, we used an anthropomorphic robotic hand to visually guide the participants’ motor imagery act and to deliver neurofeedback. Using two experimental manipulations, we investigated how a participant’s neurofeedback performance and subjective experience were influenced by the embodiability of the robotic hand, and by the neurofeedback signal’s validity. As pertains to embodiment, we found a promoting effect of robotic-hand embodiment in subjective, behavioral, electrophysiological and electrodermal measures. Regarding neurofeedback signal validity, we found some differences between real and sham neurofeedback in terms of subjective and electrodermal measures, but not in terms of behavioral and electrophysiological measures. This study motivates the further development of embodied feedback signals for NF-MIT. PMID:27869190

Visual feedback for retuning to just intonation intervals

NASA Astrophysics Data System (ADS)

Ayers, R. Dean; Nordquist, Peter R.; Corn, Justin S.

2005-04-01

Musicians become used to equal temperament pitch intervals due to their widespread use in tuning pianos and other fixed-pitch instruments. For unaccompanied singing and some other performance situations, a more harmonious blending of sounds can be achieved by shifting to just intonation intervals. Lissajous figures provide immediate and striking visual feedback that emphasizes the frequency ratios and pitch intervals found among the first few members of a single harmonic series. Spirograph patterns (hypotrochoids) are also especially simple for ratios of small whole numbers, and their use for providing feedback to singers has been suggested previously [G. W. Barton, Jr., Am. J. Phys. 44(6), 593-594 (1976)]. A hybrid mixture of these methods for comparing two frequencies generates what appears to be a three dimensional Lissajous figure-a cylindrical wire mesh that rotates about its tilted vertical axis, with zero tilt yielding the familiar Lissajous figure. Sine wave inputs work best, but the sounds of flute, recorder, whistling, and a sung ``oo'' are good enough approximations to work well. This initial study compares the three modes of presentation in terms of the ease with which a singer can obtain a desired pattern and recognize its shape.

Self-controlled concurrent feedback facilitates the learning of the final approach phase in a fixed-base flight simulator.

PubMed

Huet, Michaël; Jacobs, David M; Camachon, Cyril; Goulon, Cedric; Montagne, Gilles

2009-12-01

This study (a) compares the effectiveness of different types of feedback for novices who learn to land a virtual aircraft in a fixed-base flight simulator and (b) analyzes the informational variables that learners come to use after practice. An extensive body of research exists concerning the informational variables that allow successful landing. In contrast, few studies have examined how the attention of pilots can be directed toward these sources of information. In this study, 15 participants were asked to land a virtual Cessna 172 on 245 trials while trying to follow the glide-slope area as accurately as possible. Three groups of participants practiced under different feedback conditions: with self-controlled concurrent feedback (the self-controlled group), with imposed concurrent feedback (the yoked group), or without concurrent feedback (the control group). The self-controlled group outperformed the yoked group, which in turn outperformed the control group. Removing or manipulating specific sources of information during transfer tests had different effects for different individuals. However, removing the cockpit from the visual scene had a detrimental effect on the performance of the majority of the participants. Self-controlled concurrent feedback helps learners to more quickly attune to the informational variables that allow them to control the aircraft during the approach phase. Knowledge concerning feedback schedules can be used for the design of optimal practice methods for student pilots, and knowledge about the informational variables used by expert performers has implications for the design of cockpits and runways that facilitate the detection of these variables.

Design of a haptic device with grasp and push-pull force feedback for a master-slave surgical robot.

PubMed

Hu, Zhenkai; Yoon, Chae-Hyun; Park, Samuel Byeongjun; Jo, Yung-Ho

2016-07-01

We propose a portable haptic device providing grasp (kinesthetic) and push-pull (cutaneous) sensations for optical-motion-capture master interfaces. Although optical-motion-capture master interfaces for surgical robot systems can overcome the stiffness, friction, and coupling problems of mechanical master interfaces, it is difficult to add haptic feedback to an optical-motion-capture master interface without constraining the free motion of the operator's hands. Therefore, we utilized a Bowden cable-driven mechanism to provide the grasp and push-pull sensation while retaining the free hand motion of the optical-motion capture master interface. To evaluate the haptic device, we construct a 2-DOF force sensing/force feedback system. We compare the sensed force and the reproduced force of the haptic device. Finally, a needle insertion test was done to evaluate the performance of the haptic interface in the master-slave system. The results demonstrate that both the grasp force feedback and the push-pull force feedback provided by the haptic interface closely matched with the sensed forces of the slave robot. We successfully apply our haptic interface in the optical-motion-capture master-slave system. The results of the needle insertion test showed that our haptic feedback can provide more safety than merely visual observation. We develop a suitable haptic device to produce both kinesthetic grasp force feedback and cutaneous push-pull force feedback. Our future research will include further objective performance evaluations of the optical-motion-capture master-slave robot system with our haptic interface in surgical scenarios.

Selective and divided attention modulates auditory-vocal integration in the processing of pitch feedback errors.

PubMed

Liu, Ying; Hu, Huijing; Jones, Jeffery A; Guo, Zhiqiang; Li, Weifeng; Chen, Xi; Liu, Peng; Liu, Hanjun

2015-08-01

Speakers rapidly adjust their ongoing vocal productions to compensate for errors they hear in their auditory feedback. It is currently unclear what role attention plays in these vocal compensations. This event-related potential (ERP) study examined the influence of selective and divided attention on the vocal and cortical responses to pitch errors heard in auditory feedback regarding ongoing vocalisations. During the production of a sustained vowel, participants briefly heard their vocal pitch shifted up two semitones while they actively attended to auditory or visual events (selective attention), or both auditory and visual events (divided attention), or were not told to attend to either modality (control condition). The behavioral results showed that attending to the pitch perturbations elicited larger vocal compensations than attending to the visual stimuli. Moreover, ERPs were likewise sensitive to the attentional manipulations: P2 responses to pitch perturbations were larger when participants attended to the auditory stimuli compared to when they attended to the visual stimuli, and compared to when they were not explicitly told to attend to either the visual or auditory stimuli. By contrast, dividing attention between the auditory and visual modalities caused suppressed P2 responses relative to all the other conditions and caused enhanced N1 responses relative to the control condition. These findings provide strong evidence for the influence of attention on the mechanisms underlying the auditory-vocal integration in the processing of pitch feedback errors. In addition, selective attention and divided attention appear to modulate the neurobehavioral processing of pitch feedback errors in different ways. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Visual information transfer. 1: Assessment of specific information needs. 2: The effects of degraded motion feedback. 3: Parameters of appropriate instrument scanning behavior

NASA Technical Reports Server (NTRS)

Comstock, J. R., Jr.; Kirby, R. H.; Coates, G. D.

1984-01-01

Pilot and flight crew assessment of visually displayed information is examined as well as the effects of degraded and uncorrected motion feedback, and instrument scanning efficiency by the pilot. Computerized flight simulation and appropriate physiological measurements are used to collect data for standardization.

The Use of Visual Feedback during Signing: Evidence from Signers with Impaired Vision

ERIC Educational Resources Information Center

Emmorey, Karen; Korpics, Franco; Petronio, Karen

2009-01-01

The role of visual feedback during the production of American Sign Language was investigated by comparing the size of signing space during conversations and narrative monologues for normally sighted signers, signers with tunnel vision due to Usher syndrome, and functionally blind signers. The interlocutor for all groups was a normally sighted deaf…

Ultrasound as Visual Feedback in Speech Habilitation: Exploring Consultative Use in Rural British Columbia, Canada

ERIC Educational Resources Information Center

Bernhardt, B. May; Bacsfalvi, Penelope; Adler-Bock, Marcy; Shimizu, Reiko; Cheney, Audrey; Giesbrecht, Nathan; O'Connell, Maureen; Sirianni, Jason; Radanov, Bosko

2008-01-01

Ultrasound has shown promise as a visual feedback tool in speech therapy. Rural clients, however, often have minimal access to new technologies. The purpose of the current study was to evaluate consultative treatment using ultrasound in rural communities. Two speech-language pathologists (SLPs) trained in ultrasound use provided consultation with…

Real-time distributed video coding for 1K-pixel visual sensor networks

NASA Astrophysics Data System (ADS)

Hanca, Jan; Deligiannis, Nikos; Munteanu, Adrian

2016-07-01

Many applications in visual sensor networks (VSNs) demand the low-cost wireless transmission of video data. In this context, distributed video coding (DVC) has proven its potential to achieve state-of-the-art compression performance while maintaining low computational complexity of the encoder. Despite their proven capabilities, current DVC solutions overlook hardware constraints, and this renders them unsuitable for practical implementations. This paper introduces a DVC architecture that offers highly efficient wireless communication in real-world VSNs. The design takes into account the severe computational and memory constraints imposed by practical implementations on low-resolution visual sensors. We study performance-complexity trade-offs for feedback-channel removal, propose learning-based techniques for rate allocation, and investigate various simplifications of side information generation yielding real-time decoding. The proposed system is evaluated against H.264/AVC intra, Motion-JPEG, and our previously designed DVC prototype for low-resolution visual sensors. Extensive experimental results on various data show significant improvements in multiple configurations. The proposed encoder achieves real-time performance on a 1k-pixel visual sensor mote. Real-time decoding is performed on a Raspberry Pi single-board computer or a low-end notebook PC. To the best of our knowledge, the proposed codec is the first practical DVC deployment on low-resolution VSNs.

Error correcting mechanisms during antisaccades: contribution of online control during primary saccades and offline control via secondary saccades.

PubMed

Bedi, Harleen; Goltz, Herbert C; Wong, Agnes M F; Chandrakumar, Manokaraananthan; Niechwiej-Szwedo, Ewa

2013-01-01

Errors in eye movements can be corrected during the ongoing saccade through in-flight modifications (i.e., online control), or by programming a secondary eye movement (i.e., offline control). In a reflexive saccade task, the oculomotor system can use extraretinal information (i.e., efference copy) online to correct errors in the primary saccade, and offline retinal information to generate a secondary corrective saccade. The purpose of this study was to examine the error correction mechanisms in the antisaccade task. The roles of extraretinal and retinal feedback in maintaining eye movement accuracy were investigated by presenting visual feedback at the spatial goal of the antisaccade. We found that online control for antisaccade is not affected by the presence of visual feedback; that is whether visual feedback is present or not, the duration of the deceleration interval was extended and significantly correlated with reduced antisaccade endpoint error. We postulate that the extended duration of deceleration is a feature of online control during volitional saccades to improve their endpoint accuracy. We found that secondary saccades were generated more frequently in the antisaccade task compared to the reflexive saccade task. Furthermore, we found evidence for a greater contribution from extraretinal sources of feedback in programming the secondary "corrective" saccades in the antisaccade task. Nonetheless, secondary saccades were more corrective for the remaining antisaccade amplitude error in the presence of visual feedback of the target. Taken together, our results reveal a distinctive online error control strategy through an extension of the deceleration interval in the antisaccade task. Target feedback does not improve online control, rather it improves the accuracy of secondary saccades in the antisaccade task.

Error Correcting Mechanisms during Antisaccades: Contribution of Online Control during Primary Saccades and Offline Control via Secondary Saccades

PubMed Central

Bedi, Harleen; Goltz, Herbert C.; Wong, Agnes M. F.; Chandrakumar, Manokaraananthan; Niechwiej-Szwedo, Ewa

2013-01-01

Errors in eye movements can be corrected during the ongoing saccade through in-flight modifications (i.e., online control), or by programming a secondary eye movement (i.e., offline control). In a reflexive saccade task, the oculomotor system can use extraretinal information (i.e., efference copy) online to correct errors in the primary saccade, and offline retinal information to generate a secondary corrective saccade. The purpose of this study was to examine the error correction mechanisms in the antisaccade task. The roles of extraretinal and retinal feedback in maintaining eye movement accuracy were investigated by presenting visual feedback at the spatial goal of the antisaccade. We found that online control for antisaccade is not affected by the presence of visual feedback; that is whether visual feedback is present or not, the duration of the deceleration interval was extended and significantly correlated with reduced antisaccade endpoint error. We postulate that the extended duration of deceleration is a feature of online control during volitional saccades to improve their endpoint accuracy. We found that secondary saccades were generated more frequently in the antisaccade task compared to the reflexive saccade task. Furthermore, we found evidence for a greater contribution from extraretinal sources of feedback in programming the secondary “corrective” saccades in the antisaccade task. Nonetheless, secondary saccades were more corrective for the remaining antisaccade amplitude error in the presence of visual feedback of the target. Taken together, our results reveal a distinctive online error control strategy through an extension of the deceleration interval in the antisaccade task. Target feedback does not improve online control, rather it improves the accuracy of secondary saccades in the antisaccade task. PMID:23936308

The effect of providing feedback on the characteristics of student responses to a videotaped format for high school physics assessment

NASA Astrophysics Data System (ADS)

Lawrence, Michael John

1997-12-01

The problem of science illiteracy has been well documented. The development of the critical thinking skills in science education are often sacrificed in favor of content coverage. Opportunities for critical thinking within a context of science have been recommended to promote science literacy (AAAS, 1993). One means of doing this is to have students make and explain predictions involving physical phenomena, observe feedback, and then revise the prediction. A videotaped assessment using this process served as the focus for this study. High school physics students were asked to predict and explain what would happen in situations involving optics. They were then given different feedback treatments. The purpose of this study was to: (a) examine the effect of providing feedback on the quality of responses in making both revisions and subsequent predictions, and (b) examine the relationship between content knowledge and qualitative performance. Sixty-four high ability students were separated into three treatment groups: no feedback (NF), visual feedback (F), and teacher-explained feedback (TE). These students responded to six items on the Optics Videotape Assessment and ten optics multiple choice items from the National Physics Exam (NPE). Their teachers had previously attended a professional development institute which emphasized the practice and philosophy of assessments like the Optics Assessment. The assessment responses were categorized by two raters who used a taxonomy that ranged from simple descriptions to complete explanations. NPE performance was compared using one-way ANOVA, Optics Assessment performance was compared using a chi-square test of homogeneity, and a point-biserial correlation was done to compare qualitative and quantitative performance. The study found that students were unable to use feedback to make a significant change in the quality of their responses, whether revision or subsequent prediction. There was no correlation between content knowledge and qualitative performance. It was concluded that for students to succeed on an assessment of this type, their classroom teachers must be given the time to implement the appropriate instruction. Instruction and assessment of this nature are crucial to the development of science literacy.

A survey of telerobotic surface finishing

NASA Astrophysics Data System (ADS)

Höglund, Thomas; Alander, Jarmo; Mantere, Timo

2018-05-01

This is a survey of research published on the subjects of telerobotics, haptic feedback, and mixed reality applied to surface finishing. The survey especially focuses on how visuo-haptic feedback can be used to improve a grinding process using a remote manipulator or robot. The benefits of teleoperation and reasons for using haptic feedback are presented. The use of genetic algorithms for optimizing haptic sensing is briefly discussed. Ways of augmenting the operator's vision are described. Visual feedback can be used to find defects and analyze the quality of the surface resulting from the surface finishing process. Visual cues can also be used to aid a human operator in manipulating a robot precisely and avoiding collisions.

Visually driven chaining of elementary swim patterns into a goal-directed motor sequence: a virtual reality study of zebrafish prey capture.

PubMed

Trivedi, Chintan A; Bollmann, Johann H

2013-01-01

Prey capture behavior critically depends on rapid processing of sensory input in order to track, approach, and catch the target. When using vision, the nervous system faces the problem of extracting relevant information from a continuous stream of input in order to detect and categorize visible objects as potential prey and to select appropriate motor patterns for approach. For prey capture, many vertebrates exhibit intermittent locomotion, in which discrete motor patterns are chained into a sequence, interrupted by short periods of rest. Here, using high-speed recordings of full-length prey capture sequences performed by freely swimming zebrafish larvae in the presence of a single paramecium, we provide a detailed kinematic analysis of first and subsequent swim bouts during prey capture. Using Fourier analysis, we show that individual swim bouts represent an elementary motor pattern. Changes in orientation are directed toward the target on a graded scale and are implemented by an asymmetric tail bend component superimposed on this basic motor pattern. To further investigate the role of visual feedback on the efficiency and speed of this complex behavior, we developed a closed-loop virtual reality setup in which minimally restrained larvae recapitulated interconnected swim patterns closely resembling those observed during prey capture in freely moving fish. Systematic variation of stimulus properties showed that prey capture is initiated within a narrow range of stimulus size and velocity. Furthermore, variations in the delay and location of swim triggered visual feedback showed that the reaction time of secondary and later swims is shorter for stimuli that appear within a narrow spatio-temporal window following a swim. This suggests that the larva may generate an expectation of stimulus position, which enables accelerated motor sequencing if the expectation is met by appropriate visual feedback.

The Sander parallelogram illusion dissociates action and perception despite control for the litany of past confounds.

PubMed

Whitwell, Robert L; Goodale, Melvyn A; Merritt, Kate E; Enns, James T

2018-01-01

The two visual systems hypothesis proposes that human vision is supported by an occipito-temporal network for the conscious visual perception of the world and a fronto-parietal network for visually-guided, object-directed actions. Two specific claims about the fronto-parietal network's role in sensorimotor control have generated much data and controversy: (1) the network relies primarily on the absolute metrics of target objects, which it rapidly transforms into effector-specific frames of reference to guide the fingers, hands, and limbs, and (2) the network is largely unaffected by scene-based information extracted by the occipito-temporal network for those same targets. These two claims lead to the counter-intuitive prediction that in-flight anticipatory configuration of the fingers during object-directed grasping will resist the influence of pictorial illusions. The research confirming this prediction has been criticized for confounding the difference between grasping and explicit estimates of object size with differences in attention, sensory feedback, obstacle avoidance, metric sensitivity, and priming. Here, we address and eliminate each of these confounds. We asked participants to reach out and pick up 3D target bars resting on a picture of the Sander Parallelogram illusion and to make explicit estimates of the length of those bars. Participants performed their grasps without visual feedback, and were permitted to grasp the targets after making their size-estimates to afford them an opportunity to reduce illusory error with haptic feedback. The results show unequivocally that the effect of the illusion is stronger on perceptual judgments than on grasping. Our findings from the normally-sighted population provide strong support for the proposal that human vision is comprised of functionally and anatomically dissociable systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performing a reaching task with one arm while adapting to a visuomotor rotation with the other can lead to complete transfer of motor learning across the arms

PubMed Central

Lei, Yuming; Binder, Jeffrey R.

2015-01-01

The extent to which motor learning is generalized across the limbs is typically very limited. Here, we investigated how two motor learning hypotheses could be used to enhance the extent of interlimb transfer. According to one hypothesis, we predicted that reinforcement of successful actions by providing binary error feedback regarding task success or failure, in addition to terminal error feedback, during initial training would increase the extent of interlimb transfer following visuomotor adaptation (experiment 1). According to the other hypothesis, we predicted that performing a reaching task repeatedly with one arm without providing performance feedback (which prevented learning the task with this arm), while concurrently adapting to a visuomotor rotation with the other arm, would increase the extent of transfer (experiment 2). Results indicate that providing binary error feedback, compared with continuous visual feedback that provided movement direction and amplitude information, had no influence on the extent of transfer. In contrast, repeatedly performing (but not learning) a specific task with one arm while visuomotor adaptation occurred with the other arm led to nearly complete transfer. This suggests that the absence of motor instances associated with specific effectors and task conditions is the major reason for limited interlimb transfer and that reinforcement of successful actions during initial training is not beneficial for interlimb transfer. These findings indicate crucial contributions of effector- and task-specific motor instances, which are thought to underlie (a type of) model-free learning, to optimal motor learning and interlimb transfer. PMID:25632082

The Understanding and Interpretation of Innovative Technology-Enabled Multidimensional Physical Activity Feedback in Patients at Risk of Future Chronic Disease

PubMed Central

Western, Max J.; Peacock, Oliver J.; Stathi, Afroditi; Thompson, Dylan

2015-01-01

Background Innovative physical activity monitoring technology can be used to depict rich visual feedback that encompasses the various aspects of physical activity known to be important for health. However, it is unknown whether patients who are at risk of chronic disease would understand such sophisticated personalised feedback or whether they would find it useful and motivating. The purpose of the present study was to determine whether technology-enabled multidimensional physical activity graphics and visualisations are comprehensible and usable for patients at risk of chronic disease. Method We developed several iterations of graphics depicting minute-by-minute activity patterns and integrated physical activity health targets. Subsequently, patients at moderate/high risk of chronic disease (n=29) and healthcare practitioners (n=15) from South West England underwent full 7-days activity monitoring followed by individual semi-structured interviews in which they were asked to comment on their own personalised visual feedback Framework analysis was used to gauge their interpretation and of personalised feedback, graphics and visualisations. Results We identified two main components focussing on (a) the interpretation of feedback designs and data and (b) the impact of personalised visual physical activity feedback on facilitation of health behaviour change. Participants demonstrated a clear ability to understand the sophisticated personal information plus an enhanced physical activity knowledge. They reported that receiving multidimensional feedback was motivating and could be usefully applied to facilitate their efforts in becoming more physically active. Conclusion Multidimensional physical activity feedback can be made comprehensible, informative and motivational by using appropriate graphics and visualisations. There is an opportunity to exploit the full potential created by technological innovation and provide sophisticated personalised physical activity feedback as an adjunct to support behaviour change. PMID:25938455

The effect of conscious control on handwriting in children with attention deficit hyperactivity disorder.

PubMed

Tucha, Oliver; Lange, Klaus W

2005-08-01

Two experiments were performed regarding the effect of conscious control on handwriting fluency in healthy adults and ADHD children. First, 26 healthy students were asked to write a sentence under different conditions. The results indicate that automated handwriting movements are independent from visual feedback. Second, the writing performance of 12 children with ADHD was examined on their usual medication with methylphenidate and under placebo. In comparison to placebo, medication with methylphenidate resulted in a reduced fluency of handwriting. Automated handwriting movements could be elicited in children with ADHD on medication. The results suggest that both visual and mental control of handwriting movements affect the automation of handwriting movements. Furthermore, a simple training procedure was designed and performed in a case study of a boy with ADHD.

Relationship of ocular accommodation and motor skills performance in developmental coordination disorder.

PubMed

Rafique, Sara A; Northway, Nadia

2015-08-01

Ocular accommodation provides a well-focussed image, feedback for accurate eye movement control, and cues for depth perception. To accurately perform visually guided motor tasks, integration of ocular motor systems is essential. Children with motor coordination impairment are established to be at higher risk of accommodation anomalies. The aim of the present study was to examine the relationship between ocular accommodation and motor tasks, which are often overlooked, in order to better understand the problems experienced by children with motor coordination impairment. Visual function, gross and fine motor skills were assessed in children with developmental coordination disorder (DCD) and typically developing control children. Children with DCD had significantly poorer accommodation facility and amplitude dynamics compared to controls. Results indicate a relationship between impaired accommodation and motor skills. Specifically, accommodation anomalies correlated with visual motor, upper limb and fine dexterity task performance. Consequently, we argue accommodation anomalies influence the ineffective coordination of action and perception in DCD. Furthermore, reading disabilities were related to poorer motor performance. We postulate the role of the fastigial nucleus as a common pathway for accommodation and motor deficits. Implications of the findings and recommended visual screening protocols are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparing the accuracy of performing digital and paper checklists using a feedback package during normal workload conditions in simulated flight

NASA Astrophysics Data System (ADS)

Rantz, William Gene

This study examined whether pilots completed airplane digital or paper checklists more accurately when they received post-flight graphic and verbal feedback. Participants were 6 college student pilots with instrument rating. The task consisted of flying flight patterns using a Frasca 241 Flight Training Device which emulates a Cirrus SR20 aircraft. The main dependent variable was the number of checklist items completed correctly per flight. An alternating treatment, multiple baseline design across pairs with reversal, was used. During baseline, the average percent of correctly completed items per flight varied considerably across participants, ranging from 13% to 57% for traditional paper checklists and ranging from 11% to 67% for digital checklists. Checklist performance increased to an average of 90% for paper checklist and an average of 89% for digital checklists after participants were given feedback and praise, and continued to improve to an average of nearly 100% for paper checklists and an average of 99% for digital checklists after the feedback and praise were removed. A slight decrement in performance was observed during a post-experiment probe between 60--90 days. Visual inspection and statistical analysis of the data suggest that paper checklist accuracy does not differ significantly from digital checklist accuracy. The results suggest that graphic feedback and praise can be used to increase the extent to which pilots use both digital and paper checklists accurately during normal workload conditions.

A low cost real-time motion tracking approach using webcam technology.

PubMed

Krishnan, Chandramouli; Washabaugh, Edward P; Seetharaman, Yogesh

2015-02-05

Physical therapy is an important component of gait recovery for individuals with locomotor dysfunction. There is a growing body of evidence that suggests that incorporating a motor learning task through visual feedback of movement trajectory is a useful approach to facilitate therapeutic outcomes. Visual feedback is typically provided by recording the subject's limb movement patterns using a three-dimensional motion capture system and displaying it in real-time using customized software. However, this approach can seldom be used in the clinic because of the technical expertise required to operate this device and the cost involved in procuring a three-dimensional motion capture system. In this paper, we describe a low cost two-dimensional real-time motion tracking approach using a simple webcam and an image processing algorithm in LabVIEW Vision Assistant. We also evaluated the accuracy of this approach using a high precision robotic device (Lokomat) across various walking speeds. Further, the reliability and feasibility of real-time motion-tracking were evaluated in healthy human participants. The results indicated that the measurements from the webcam tracking approach were reliable and accurate. Experiments on human subjects also showed that participants could utilize the real-time kinematic feedback generated from this device to successfully perform a motor learning task while walking on a treadmill. These findings suggest that the webcam motion tracking approach is a feasible low cost solution to perform real-time movement analysis and training. Copyright © 2014 Elsevier Ltd. All rights reserved.

A low cost real-time motion tracking approach using webcam technology

PubMed Central

Krishnan, Chandramouli; Washabaugh, Edward P.; Seetharaman, Yogesh

2014-01-01

Physical therapy is an important component of gait recovery for individuals with locomotor dysfunction. There is a growing body of evidence that suggests that incorporating a motor learning task through visual feedback of movement trajectory is a useful approach to facilitate therapeutic outcomes. Visual feedback is typically provided by recording the subject’s limb movement patterns using a three-dimensional motion capture system and displaying it in real-time using customized software. However, this approach can seldom be used in the clinic because of the technical expertise required to operate this device and the cost involved in procuring a three-dimensional motion capture system. In this paper, we describe a low cost two-dimensional real-time motion tracking approach using a simple webcam and an image processing algorithm in LabVIEW Vision Assistant. We also evaluated the accuracy of this approach using a high precision robotic device (Lokomat) across various walking speeds. Further, the reliability and feasibility of real-time motion-tracking were evaluated in healthy human participants. The results indicated that the measurements from the webcam tracking approach were reliable and accurate. Experiments on human subjects also showed that participants could utilize the real-time kinematic feedback generated from this device to successfully perform a motor learning task while walking on a treadmill. These findings suggest that the webcam motion tracking approach is a feasible low cost solution to perform real-time movement analysis and training. PMID:25555306

Updating Target Location at the End of an Orienting Saccade Affects the Characteristics of Simple Point-to-Point Movements

ERIC Educational Resources Information Center

Desmurget, Michel; Turner, Robert S.; Prablanc, Claude; Russo, Gary S.; Alexander, Garret E.; Grafton, Scott T.

2005-01-01

Six results are reported. (a) Reaching accuracy increases when visual capture of the target is allowed (e.g., target on vs. target off at saccade onset). (b) Whatever the visual condition, trajectories diverge only after peak acceleration, suggesting that accuracy is improved through feedback mechanisms. (c) Feedback corrections are smoothly…

Encouraging Electricity Savings in a University Residential Hall through a Combination of Feedback, Visual Prompts, and Incentives

ERIC Educational Resources Information Center

Bekker, Marthinus J.; Cumming, Tania D.; Osborne, Nikola K. P.; Bruining, Angela M.; McClean, Julia I.; Leland, Louis S., Jr.

2010-01-01

This experiment investigated the combined use of visual prompts, daily feedback, and rewards to reduce electricity consumption in a university residential hall. After a 17-day baseline period, the experimental intervention was introduced in the intervention hall, and no change was made in the control hall. Energy usage decreased in the…

THE EFFECT OF VISUAL FEEDBACK ON PRONUNCIATION IN FOREIGN LANGUAGE LEARNING. TERMINATION OF RESEARCH REPORT.

ERIC Educational Resources Information Center

JENSON, PAUL G.; WESTERMEIER, FRANZ X.

A RESEARCH PROJECT USING THE OSCILLOSCOPE TO DETERMINE VISUAL FEEDBACK IN THE TEACHING OF FOREIGN LANGUAGE PRONUNCIATION WAS TERMINATED BECAUSE OF TECHNICAL DIFFICULTIES THAT COULD NOT BE RESOLVED WITH THE EQUIPMENT AVAILABLE. FAILURE IS ATTRIBUTED TO SUCH FACTORS AS (1) THE SPEECH SOUND WAVES SOUND THE SAME THOUGH THEIR WAVE SHAPES DIFFER, (2)…

The Impact of Feedback on Self-Rated Driving Ability and Driving Self-Regulation among Older Adults

ERIC Educational Resources Information Center

Ackerman, Michelle L.; Crowe, Michael; Vance, David E.; Wadley, Virginia G.; Owsley, Cynthia; Ball, Karlene K.

2011-01-01

In 129 community-dwelling older adults, feedback regarding qualification for an insurance discount (based on a visual speed of processing test; Useful Field of View) was examined as a prospective predictor of change in self-reported driving ability, driving avoidance, and driving exposure over 3 months, along with physical, visual, health, and…

Effects of Oxytocin and Vasopressin on Preferential Brain Responses to Negative Social Feedback.

PubMed

Gozzi, Marta; Dashow, Erica M; Thurm, Audrey; Swedo, Susan E; Zink, Caroline F

2017-06-01

Receiving negative social feedback can be detrimental to emotional, cognitive, and physical well-being, and fear of negative social feedback is a prominent feature of mental illnesses that involve social anxiety. A large body of evidence has implicated the neuropeptides oxytocin and vasopressin in the modulation of human neural activity underlying social cognition, including negative emotion processing; however, the influence of oxytocin and vasopressin on neural activity elicited during negative social evaluation remains unknown. Here 21 healthy men underwent functional magnetic resonance imaging in a double-blind, placebo-controlled, crossover design to determine how intranasally administered oxytocin and vasopressin modulated neural activity when receiving negative feedback on task performance from a study investigator. We found that under placebo, a preferential response to negative social feedback compared with positive social feedback was evoked in brain regions putatively involved in theory of mind (temporoparietal junction), pain processing (anterior insula and supplementary motor area), and identification of emotionally important visual cues in social perception (right fusiform). These activations weakened with oxytocin and vasopressin administration such that neural responses to receiving negative social feedback were not significantly greater than positive social feedback. Our results show effects of both oxytocin and vasopressin on the brain network involved in negative social feedback, informing the possible use of a pharmacological approach targeting these regions in multiple disorders with impairments in social information processing.

Ultrasound visual feedback treatment and practice variability for residual speech sound errors

PubMed Central

Preston, Jonathan L.; McCabe, Patricia; Rivera-Campos, Ahmed; Whittle, Jessica L.; Landry, Erik; Maas, Edwin

2014-01-01

Purpose The goals were to (1) test the efficacy of a motor-learning based treatment that includes ultrasound visual feedback for individuals with residual speech sound errors, and (2) explore whether the addition of prosodic cueing facilitates speech sound learning. Method A multiple baseline single subject design was used, replicated across 8 participants. For each participant, one sound context was treated with ultrasound plus prosodic cueing for 7 sessions, and another sound context was treated with ultrasound but without prosodic cueing for 7 sessions. Sessions included ultrasound visual feedback as well as non-ultrasound treatment. Word-level probes assessing untreated words were used to evaluate retention and generalization. Results For most participants, increases in accuracy of target sound contexts at the word level were observed with the treatment program regardless of whether prosodic cueing was included. Generalization between onset singletons and clusters was observed, as well as generalization to sentence-level accuracy. There was evidence of retention during post-treatment probes, including at a two-month follow-up. Conclusions A motor-based treatment program that includes ultrasound visual feedback can facilitate learning of speech sounds in individuals with residual speech sound errors. PMID:25087938

Prism adaptation in virtual and natural contexts: Evidence for a flexible adaptive process.

PubMed

Veilleux, Louis-Nicolas; Proteau, Luc

2015-01-01

Prism exposure when aiming at a visual target in a virtual condition (e.g., when the hand is represented by a video representation) produces no or only small adaptations (after-effects), whereas prism exposure in a natural condition produces large after-effects. Some researchers suggested that this difference may arise from distinct adaptive processes, but other studies suggested a unique process. The present study reconciled these conflicting interpretations. Forty participants were divided into two groups: One group used visual feedback of their hand (natural context), and the other group used computer-generated representational feedback (virtual context). Visual feedback during adaptation was concurrent or terminal. All participants underwent laterally displacing prism perturbation. The results showed that the after-effects were twice as large in the "natural context" than in the "virtual context". No significant differences were observed between the concurrent and terminal feedback conditions. The after-effects generalized to untested targets and workspace. These results suggest that prism adaptation in virtual and natural contexts involves the same process. The smaller after-effects in the virtual context suggest that the depth of adaptation is a function of the degree of convergence between the proprioceptive and visual information that arises from the hand.

Semi-Immersive Virtual Turbine Engine Simulation System

NASA Astrophysics Data System (ADS)

Abidi, Mustufa H.; Al-Ahmari, Abdulrahman M.; Ahmad, Ali; Darmoul, Saber; Ameen, Wadea

2018-05-01

The design and verification of assembly operations is essential for planning product production operations. Recently, virtual prototyping has witnessed tremendous progress, and has reached a stage where current environments enable rich and multi-modal interaction between designers and models through stereoscopic visuals, surround sound, and haptic feedback. The benefits of building and using Virtual Reality (VR) models in assembly process verification are discussed in this paper. In this paper, we present the virtual assembly (VA) of an aircraft turbine engine. The assembly parts and sequences are explained using a virtual reality design system. The system enables stereoscopic visuals, surround sounds, and ample and intuitive interaction with developed models. A special software architecture is suggested to describe the assembly parts and assembly sequence in VR. A collision detection mechanism is employed that provides visual feedback to check the interference between components. The system is tested for virtual prototype and assembly sequencing of a turbine engine. We show that the developed system is comprehensive in terms of VR feedback mechanisms, which include visual, auditory, tactile, as well as force feedback. The system is shown to be effective and efficient for validating the design of assembly, part design, and operations planning.

Cortical excitability correlates with the event-related desynchronization during brain-computer interface control

NASA Astrophysics Data System (ADS)

Daly, Ian; Blanchard, Caroline; Holmes, Nicholas P.

2018-04-01

Objective. Brain-computer interfaces (BCIs) based on motor control have been suggested as tools for stroke rehabilitation. Some initial successes have been achieved with this approach, however the mechanism by which they work is not yet fully understood. One possible part of this mechanism is a, previously suggested, relationship between the strength of the event-related desynchronization (ERD), a neural correlate of motor imagination and execution, and corticospinal excitability. Additionally, a key component of BCIs used in neurorehabilitation is the provision of visual feedback to positively reinforce attempts at motor control. However, the ability of visual feedback of the ERD to modulate the activity in the motor system has not been fully explored. Approach. We investigate these relationships via transcranial magnetic stimulation delivered at different moments in the ongoing ERD related to hand contraction and relaxation during BCI control of a visual feedback bar. Main results. We identify a significant relationship between ERD strength and corticospinal excitability, and find that our visual feedback does not affect corticospinal excitability. Significance. Our results imply that efforts to promote functional recovery in stroke by targeting increases in corticospinal excitability may be aided by accounting for the time course of the ERD.

Visual landmarks facilitate rodent spatial navigation in virtual reality environments

PubMed Central

Youngstrom, Isaac A.; Strowbridge, Ben W.

2012-01-01

Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain areas. Virtual reality offers a unique approach to ask whether visual landmark cues alone are sufficient to improve performance in a spatial task. We found that mice could learn to navigate between two water reward locations along a virtual bidirectional linear track using a spherical treadmill. Mice exposed to a virtual environment with vivid visual cues rendered on a single monitor increased their performance over a 3-d training regimen. Training significantly increased the percentage of time avatars controlled by the mice spent near reward locations in probe trials without water rewards. Neither improvement during training or spatial learning for reward locations occurred with mice operating a virtual environment without vivid landmarks or with mice deprived of all visual feedback. Mice operating the vivid environment developed stereotyped avatar turning behaviors when alternating between reward zones that were positively correlated with their performance on the probe trial. These results suggest that mice are able to learn to navigate to specific locations using only visual cues presented within a virtual environment rendered on a single computer monitor. PMID:22345484

Robotic guidance benefits the learning of dynamic, but not of spatial movement characteristics.

PubMed

Lüttgen, Jenna; Heuer, Herbert

2012-10-01

Robotic guidance is an engineered form of haptic-guidance training and intended to enhance motor learning in rehabilitation, surgery, and sports. However, its benefits (and pitfalls) are still debated. Here, we investigate the effects of different presentation modes on the reproduction of a spatiotemporal movement pattern. In three different groups of participants, the movement was demonstrated in three different modalities, namely visual, haptic, and visuo-haptic. After demonstration, participants had to reproduce the movement in two alternating recall conditions: haptic and visuo-haptic. Performance of the three groups during recall was compared with regard to spatial and dynamic movement characteristics. After haptic presentation, participants showed superior dynamic accuracy, whereas after visual presentation, participants performed better with regard to spatial accuracy. Added visual feedback during recall always led to enhanced performance, independent of the movement characteristic and the presentation modality. These findings substantiate the different benefits of different presentation modes for different movement characteristics. In particular, robotic guidance is beneficial for the learning of dynamic, but not of spatial movement characteristics.

Research on flight stability performance of rotor aircraft based on visual servo control method

NASA Astrophysics Data System (ADS)

Yu, Yanan; Chen, Jing

2016-11-01

control method based on visual servo feedback is proposed, which is used to improve the attitude of a quad-rotor aircraft and to enhance its flight stability. Ground target images are obtained by a visual platform fixed on aircraft. Scale invariant feature transform (SIFT) algorism is used to extract image feature information. According to the image characteristic analysis, fast motion estimation is completed and used as an input signal of PID flight control system to realize real-time status adjustment in flight process. Imaging tests and simulation results show that the method proposed acts good performance in terms of flight stability compensation and attitude adjustment. The response speed and control precision meets the requirements of actual use, which is able to reduce or even eliminate the influence of environmental disturbance. So the method proposed has certain research value to solve the problem of aircraft's anti-disturbance.

Timing, timing, timing: Fast decoding of object information from intracranial field potentials in human visual cortex

PubMed Central

Liu, Hesheng; Agam, Yigal; Madsen, Joseph R.; Kreiman, Gabriel

2010-01-01

Summary The difficulty of visual recognition stems from the need to achieve high selectivity while maintaining robustness to object transformations within hundreds of milliseconds. Theories of visual recognition differ in whether the neuronal circuits invoke recurrent feedback connections or not. The timing of neurophysiological responses in visual cortex plays a key role in distinguishing between bottom-up and top-down theories. Here we quantified at millisecond resolution the amount of visual information conveyed by intracranial field potentials from 912 electrodes in 11 human subjects. We could decode object category information from human visual cortex in single trials as early as 100 ms post-stimulus. Decoding performance was robust to depth rotation and scale changes. The results suggest that physiological activity in the temporal lobe can account for key properties of visual recognition. The fast decoding in single trials is compatible with feed-forward theories and provides strong constraints for computational models of human vision. PMID:19409272

Visual servoing in medical robotics: a survey. Part I: endoscopic and direct vision imaging - techniques and applications.

PubMed

Azizian, Mahdi; Khoshnam, Mahta; Najmaei, Nima; Patel, Rajni V

2014-09-01

Intra-operative imaging is widely used to provide visual feedback to a clinician when he/she performs a procedure. In visual servoing, surgical instruments and parts of tissue/body are tracked by processing the acquired images. This information is then used within a control loop to manoeuvre a robotic manipulator during a procedure. A comprehensive search of electronic databases was completed for the period 2000-2013 to provide a survey of the visual servoing applications in medical robotics. The focus is on medical applications where image-based tracking is used for closed-loop control of a robotic system. Detailed classification and comparative study of various contributions in visual servoing using endoscopic or direct visual images are presented and summarized in tables and diagrams. The main challenges in using visual servoing for medical robotic applications are identified and potential future directions are suggested. 'Supervised automation of medical robotics' is found to be a major trend in this field. Copyright © 2013 John Wiley & Sons, Ltd.

A computerized tablet with visual feedback of hand position for functional magnetic resonance imaging

PubMed Central

Karimpoor, Mahta; Tam, Fred; Strother, Stephen C.; Fischer, Corinne E.; Schweizer, Tom A.; Graham, Simon J.

2015-01-01

Neuropsychological tests behavioral tasks that very commonly involve handwriting and drawing are widely used in the clinic to detect abnormal brain function. Functional magnetic resonance imaging (fMRI) may be useful in increasing the specificity of such tests. However, performing complex pen-and-paper tests during fMRI involves engineering challenges. Previously, we developed an fMRI-compatible, computerized tablet system to address this issue. However, the tablet did not include visual feedback of hand position (VFHP), a human factors component that may be important for fMRI of certain patient populations. A real-time system was thus developed to provide VFHP and integrated with the tablet in an augmented reality display. The effectiveness of the system was initially tested in young healthy adults who performed various handwriting tasks in front of a computer display with and without VFHP. Pilot fMRI of writing tasks were performed by two representative individuals with and without VFHP. Quantitative analysis of the behavioral results indicated improved writing performance with VFHP. The pilot fMRI results suggest that writing with VFHP requires less neural resources compared to the without VFHP condition, to maintain similar behavior. Thus, the tablet system with VFHP is recommended for future fMRI studies involving patients with impaired brain function and where ecologically valid behavior is important. PMID:25859201

Direction of Magnetoencephalography Sources Associated with Feedback and Feedforward Contributions in a Visual Object Recognition Task

PubMed Central

Ahlfors, Seppo P.; Jones, Stephanie R.; Ahveninen, Jyrki; Hämäläinen, Matti S.; Belliveau, John W.; Bar, Moshe

2014-01-01

Identifying inter-area communication in terms of the hierarchical organization of functional brain areas is of considerable interest in human neuroimaging. Previous studies have suggested that the direction of magneto- and electroencephalography (MEG, EEG) source currents depends on the layer-specific input patterns into a cortical area. We examined the direction in MEG source currents in a visual object recognition experiment in which there were specific expectations of activation in the fusiform region being driven by either feedforward or feedback inputs. The source for the early non-specific visual evoked response, presumably corresponding to feedforward driven activity, pointed outward, i.e., away from the white matter. In contrast, the source for the later, object-recognition related signals, expected to be driven by feedback inputs, pointed inward, toward the white matter. Associating specific features of the MEG/EEG source waveforms to feedforward and feedback inputs could provide unique information about the activation patterns within hierarchically organized cortical areas. PMID:25445356

Independent voluntary correction and savings in locomotor learning.

PubMed

Leech, Kristan A; Roemmich, Ryan T

2018-06-14

People can acquire new walking patterns in many different ways. For example, we can change our gait voluntarily in response to instruction or adapt by sensing our movement errors. Here we investigated how acquisition of a new walking pattern through simultaneous voluntary correction and adaptive learning affected the resulting motor memory of the learned pattern. We studied adaptation to split-belt treadmill walking with and without visual feedback of stepping patterns. As expected, visual feedback enabled faster acquisition of the new walking pattern. However, upon later re-exposure to the same split-belt perturbation, participants exhibited similar motor memories whether they had learned with or without visual feedback. Participants who received feedback did not re-engage the mechanism used to accelerate initial acquisition of the new walking pattern to similarly accelerate subsequent relearning. These findings reveal that voluntary correction neither benefits nor interferes with the ability to save a new walking pattern over time. © 2018. Published by The Company of Biologists Ltd.

Learning receptive fields using predictive feedback.

PubMed

Jehee, Janneke F M; Rothkopf, Constantin; Beck, Jeffrey M; Ballard, Dana H

2006-01-01

Previously, it was suggested that feedback connections from higher- to lower-level areas carry predictions of lower-level neural activities, whereas feedforward connections carry the residual error between the predictions and the actual lower-level activities [Rao, R.P.N., Ballard, D.H., 1999. Nature Neuroscience 2, 79-87.]. A computational model implementing the hypothesis learned simple cell receptive fields when exposed to natural images. Here, we use predictive feedback to explain tuning properties in medial superior temporal area (MST). We implement the hypothesis using a new, biologically plausible, algorithm based on matching pursuit, which retains all the features of the previous implementation, including its ability to efficiently encode input. When presented with natural images, the model developed receptive field properties as found in primary visual cortex. In addition, when exposed to visual motion input resulting from movements through space, the model learned receptive field properties resembling those in MST. These results corroborate the idea that predictive feedback is a general principle used by the visual system to efficiently encode natural input.

Visualizing Dataflow Graphs of Deep Learning Models in TensorFlow.

PubMed

Wongsuphasawat, Kanit; Smilkov, Daniel; Wexler, James; Wilson, Jimbo; Mane, Dandelion; Fritz, Doug; Krishnan, Dilip; Viegas, Fernanda B; Wattenberg, Martin

2018-01-01

We present a design study of the TensorFlow Graph Visualizer, part of the TensorFlow machine intelligence platform. This tool helps users understand complex machine learning architectures by visualizing their underlying dataflow graphs. The tool works by applying a series of graph transformations that enable standard layout techniques to produce a legible interactive diagram. To declutter the graph, we decouple non-critical nodes from the layout. To provide an overview, we build a clustered graph using the hierarchical structure annotated in the source code. To support exploration of nested structure on demand, we perform edge bundling to enable stable and responsive cluster expansion. Finally, we detect and highlight repeated structures to emphasize a model's modular composition. To demonstrate the utility of the visualizer, we describe example usage scenarios and report user feedback. Overall, users find the visualizer useful for understanding, debugging, and sharing the structures of their models.

A systematic review of phacoemulsification cataract surgery in virtual reality simulators.

PubMed

Lam, Chee Kiang; Sundaraj, Kenneth; Sulaiman, Mohd Nazri

2013-01-01

The aim of this study was to review the capability of virtual reality simulators in the application of phacoemulsification cataract surgery training. Our review included the scientific publications on cataract surgery simulators that had been developed by different groups of researchers along with commercialized surgical training products, such as EYESI® and PhacoVision®. The review covers the simulation of the main cataract surgery procedures, i.e., corneal incision, capsulorrhexis, phacosculpting, and intraocular lens implantation in various virtual reality surgery simulators. Haptics realism and visual realism of the procedures are the main elements in imitating the actual surgical environment. The involvement of ophthalmology in research on virtual reality since the early 1990s has made a great impact on the development of surgical simulators. Most of the latest cataract surgery training systems are able to offer high fidelity in visual feedback and haptics feedback, but visual realism, such as the rotational movements of an eyeball with response to the force applied by surgical instruments, is still lacking in some of them. The assessment of the surgical tasks carried out on the simulators showed a significant difference in the performance before and after the training.

The spatial range of contour integration deficits in schizophrenia

PubMed Central

Silverstein, Steven M.; Barch, Deanna M.; Carter, Cameron S.; Gold, James M.; Kovács, Ilona; MacDonald, Angus W.; Ragland, J. Daniel; Strauss, Milton E.

2012-01-01

Contour integration (CI) refers to the process that represents spatially separated elements as a unified edge or closed shape. Schizophrenia is a psychiatric disorder characterized by symptoms such as hallucinations, delusions, disorganized thinking, inappropriate affect, and social withdrawal. Persons with schizophrenia are impaired at CI, but the specific mechanisms underlying the deficit are still not clear. Here, we explored the hypothesis that poor patient performance owes to reduced feedback or impaired longer-range lateral connectivity within early visual cortex—functionally similar to that found in 5- to 6-year old children. This hypothesis predicts that as target element spacing increases from .7 to 1.4° of visual angle, patient impairments will become more pronounced. As a test of the prediction, 25 healthy controls and 36 clinically stable, asymptomatic persons with schizophrenia completed a CI task that involved determining whether a subset of Gabor elements formed a leftward or rightward pointing shape. Adjacent shape elements were spaced at either .7 or 1.4° of visual angle. Difficulty in each spacing condition depended on the number of noise elements present. Patients performed worse than controls overall, both groups performed worse with the larger spacing, and the magnitude of the between-group difference was not amplified at the larger spacing. These results show that CI deficits in schizophrenia cannot be explained in terms of a reduced spatial range of integration, at least not when the shape elements are spaced within 1.5°. Later-developing, low-level integrative mechanisms of lateral connectivity and feedback appear not to be differentially impaired in the illness. PMID:22710617

Visual-Manipulative Response Strategies in Infant Operant Conditioning with Spatially Displaced Feedback.

ERIC Educational Resources Information Center

Millar, W. Stuart; Schaffer, H. Rudolph

Six- and nine-month-old infants were exposed to contingent or non-contingent perceptual stimulation from a source which was spatially displaced at 60 from the infant's midline. Reliable operant acquisition was observed in the case of the nine-month-old infants, but not in the case of the six-month-old infants whose performance was similar to that…

Multimodal Speech Capture System for Speech Rehabilitation and Learning.

PubMed

Sebkhi, Nordine; Desai, Dhyey; Islam, Mohammad; Lu, Jun; Wilson, Kimberly; Ghovanloo, Maysam

2017-11-01

Speech-language pathologists (SLPs) are trained to correct articulation of people diagnosed with motor speech disorders by analyzing articulators' motion and assessing speech outcome while patients speak. To assist SLPs in this task, we are presenting the multimodal speech capture system (MSCS) that records and displays kinematics of key speech articulators, the tongue and lips, along with voice, using unobtrusive methods. Collected speech modalities, tongue motion, lips gestures, and voice are visualized not only in real-time to provide patients with instant feedback but also offline to allow SLPs to perform post-analysis of articulators' motion, particularly the tongue, with its prominent but hardly visible role in articulation. We describe the MSCS hardware and software components, and demonstrate its basic visualization capabilities by a healthy individual repeating the words "Hello World." A proof-of-concept prototype has been successfully developed for this purpose, and will be used in future clinical studies to evaluate its potential impact on accelerating speech rehabilitation by enabling patients to speak naturally. Pattern matching algorithms to be applied to the collected data can provide patients with quantitative and objective feedback on their speech performance, unlike current methods that are mostly subjective, and may vary from one SLP to another.

Promoting Increased Pitch Variation in Oral Presentations with Transient Visual Feedback

ERIC Educational Resources Information Center

Hincks, Rebecca; Edlund, Jens

2009-01-01

This paper investigates learner response to a novel kind of intonation feedback generated from speech analysis. Instead of displays of pitch curves, our feedback is flashing lights that show how much pitch variation the speaker has produced. The variable used to generate the feedback is the standard deviation of fundamental frequency as measured…

Distinct roles of the cortical layers of area V1 in figure-ground segregation.

PubMed

Self, Matthew W; van Kerkoerle, Timo; Supèr, Hans; Roelfsema, Pieter R

2013-11-04

What roles do the different cortical layers play in visual processing? We recorded simultaneously from all layers of the primary visual cortex while monkeys performed a figure-ground segregation task. This task can be divided into different subprocesses that are thought to engage feedforward, horizontal, and feedback processes at different time points. These different connection types have different patterns of laminar terminations in V1 and can therefore be distinguished with laminar recordings. We found that the visual response started 40 ms after stimulus presentation in layers 4 and 6, which are targets of feedforward connections from the lateral geniculate nucleus and distribute activity to the other layers. Boundary detection started shortly after the visual response. In this phase, boundaries of the figure induced synaptic currents and stronger neuronal responses in upper layer 4 and the superficial layers ~70 ms after stimulus onset, consistent with the hypothesis that they are detected by horizontal connections. In the next phase, ~30 ms later, synaptic inputs arrived in layers 1, 2, and 5 that receive feedback from higher visual areas, which caused the filling in of the representation of the entire figure with enhanced neuronal activity. The present results reveal unique contributions of the different cortical layers to the formation of a visual percept. This new blueprint of laminar processing may generalize to other tasks and to other areas of the cerebral cortex, where the layers are likely to have roles similar to those in area V1. Copyright © 2013 Elsevier Ltd. All rights reserved.

Visualizations of Travel Time Performance Based on Vehicle Reidentification Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Stanley Ernest; Sharifi, Elham; Day, Christopher M.

This paper provides a visual reference of the breadth of arterial performance phenomena based on travel time measures obtained from reidentification technology that has proliferated in the past 5 years. These graphical performance measures are revealed through overlay charts and statistical distribution as revealed through cumulative frequency diagrams (CFDs). With overlays of vehicle travel times from multiple days, dominant traffic patterns over a 24-h period are reinforced and reveal the traffic behavior induced primarily by the operation of traffic control at signalized intersections. A cumulative distribution function in the statistical literature provides a method for comparing traffic patterns from variousmore » time frames or locations in a compact visual format that provides intuitive feedback on arterial performance. The CFD may be accumulated hourly, by peak periods, or by time periods specific to signal timing plans that are in effect. Combined, overlay charts and CFDs provide visual tools with which to assess the quality and consistency of traffic movement for various periods throughout the day efficiently, without sacrificing detail, which is a typical byproduct of numeric-based performance measures. These methods are particularly effective for comparing before-and-after median travel times, as well as changes in interquartile range, to assess travel time reliability.« less

Man-systems evaluation of moving base vehicle simulation motion cues. [human acceleration perception involving visual feedback

NASA Technical Reports Server (NTRS)

Kirkpatrick, M.; Brye, R. G.

1974-01-01

A motion cue investigation program is reported that deals with human factor aspects of high fidelity vehicle simulation. General data on non-visual motion thresholds and specific threshold values are established for use as washout parameters in vehicle simulation. A general purpose similator is used to test the contradictory cue hypothesis that acceleration sensitivity is reduced during a vehicle control task involving visual feedback. The simulator provides varying acceleration levels. The method of forced choice is based on the theory of signal detect ability.

Adaptation effects in static postural control by providing simultaneous visual feedback of center of pressure and center of gravity.

PubMed

Takeda, Kenta; Mani, Hiroki; Hasegawa, Naoya; Sato, Yuki; Tanaka, Shintaro; Maejima, Hiroshi; Asaka, Tadayoshi

2017-07-19

The benefit of visual feedback of the center of pressure (COP) on quiet standing is still debatable. This study aimed to investigate the adaptation effects of visual feedback training using both the COP and center of gravity (COG) during quiet standing. Thirty-four healthy young adults were divided into three groups randomly (COP + COG, COP, and control groups). A force plate was used to calculate the coordinates of the COP in the anteroposterior (COP AP ) and mediolateral (COP ML ) directions. A motion analysis system was used to calculate the coordinates of the center of mass (COM) in both directions (COM AP and COM ML ). The coordinates of the COG in the AP direction (COG AP ) were obtained from the force plate signals. Augmented visual feedback was presented on a screen in the form of fluctuation circles in the vertical direction that moved upward as the COP AP and/or COG AP moved forward and vice versa. The COP + COG group received the real-time COP AP and COG AP feedback simultaneously, whereas the COP group received the real-time COP AP feedback only. The control group received no visual feedback. In the training session, the COP + COG group was required to maintain an even distance between the COP AP and COG AP and reduce the COG AP fluctuation, whereas the COP group was required to reduce the COP AP fluctuation while standing on a foam pad. In test sessions, participants were instructed to keep their standing posture as quiet as possible on the foam pad before (pre-session) and after (post-session) the training sessions. In the post-session, the velocity and root mean square of COM AP in the COP + COG group were lower than those in the control group. In addition, the absolute value of the sum of the COP - COM distances in the COP + COG group was lower than that in the COP group. Furthermore, positive correlations were found between the COM AP velocity and COP - COM parameters. The results suggest that the novel visual feedback training that incorporates the COP AP -COG AP interaction reduces postural sway better than the training using the COP AP alone during quiet standing. That is, even COP AP fluctuation around the COG AP would be effective in reducing the COM AP velocity.

Randomised crossover trial of rate feedback and force during chest compressions for paediatric cardiopulmonary resuscitation.

PubMed

Gregson, Rachael Kathleen; Cole, Tim James; Skellett, Sophie; Bagkeris, Emmanouil; Welsby, Denise; Peters, Mark John

2017-05-01

To determine the effect of visual feedback on rate of chest compressions, secondarily relating the forces used. Randomised crossover trial. Tertiary teaching hospital. Fifty trained hospital staff. A thin sensor-mat placed over the manikin's chest measured rate and force. Rescuers applied compressions to the same paediatric manikin for two sessions. During one session they received visual feedback comparing their real-time rate with published guidelines. Primary: compression rate. Secondary: compression and residual forces. Rate of chest compressions (compressions per minute (compressions per minute; cpm)) varied widely (mean (SD) 111 (13), range 89-168), with a fourfold difference in variation during session 1 between those receiving and not receiving feedback (108 (5) vs 120 (20)). The interaction of session by feedback order was highly significant, indicating that this difference in mean rate between sessions was 14 cpm less (95% CI -22 to -5, p=0.002) in those given feedback first compared with those given it second. Compression force (N) varied widely (mean (SD) 306 (94); range 142-769). Those receiving feedback second (as opposed to first) used significantly lower force (adjusted mean difference -80 (95% CI -128 to -32), p=0.002). Mean residual force (18 N, SD 12, range 0-49) was unaffected by the intervention. While visual feedback restricted excessive compression rates to within the prescribed range, applied force remained widely variable. The forces required may differ with growth, but such variation treating one manikin is alarming. Feedback technologies additionally measuring force (effort) could help to standardise and define effective treatments throughout childhood. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Effectiveness of basic display augmentation in vehicular control by visual field cues

NASA Technical Reports Server (NTRS)

Grunwald, A. J.; Merhav, S. J.

1978-01-01

The paper investigates the effectiveness of different basic display augmentation concepts - fixed reticle, velocity vector, and predicted future vehicle path - for RPVs controlled by a vehicle-mounted TV camera. The task is lateral manual control of a low flying RPV along a straight reference line in the presence of random side gusts. The man-machine system and the visual interface are modeled as a linear time-invariant system. Minimization of a quadratic performance criterion is assumed to underlie the control strategy of a well-trained human operator. The solution for the optimal feedback matrix enables the explicit computation of the variances of lateral deviation and directional error of the vehicle and of the control force that are used as performance measures.

The influence of age, sex, bulb position, visual feedback, and the order of testing on maximum anterior and posterior tongue strength and endurance in healthy belgian adults.

PubMed

Vanderwegen, Jan; Guns, Cindy; Van Nuffelen, Gwen; Elen, Rik; De Bodt, Marc

2013-06-01

This study collected data on the maximum anterior and posterior tongue strength and endurance in 420 healthy Belgians across the adult life span to explore the influence of age, sex, bulb position, visual feedback, and order of testing. Measures were obtained using the Iowa Oral Performance Instrument (IOPI). Older participants (more than 70 years old) demonstrated significantly lower strength than younger persons at the anterior and the posterior tongue. Endurance remains stable throughout the major part of life. Gender influence remains significant but minor throughout life, with males showing higher pressures and longer endurance. The anterior part of the tongue has both higher strength and longer endurance than the posterior part. Mean maximum tongue pressures in this European population seem to be lower than American values and are closer to Asian results. The normative data can be used for objective assessment of tongue weakness and subsequent therapy planning of dysphagic patients.

Quality of closed chest compression on a manikin in ambulance vehicles and flying helicopters with a real time automated feedback.

PubMed

Havel, Christof; Schreiber, Wolfgang; Trimmel, Helmut; Malzer, Reinhard; Haugk, Moritz; Richling, Nina; Riedmüller, Eva; Sterz, Fritz; Herkner, Harald

2010-01-01

Automated verbal and visual feedback improves quality of resuscitation in out-of-hospital cardiac arrest and was proven to increase short-term survival. Quality of resuscitation may be hampered in more difficult situations like emergency transportation. Currently there is no evidence if feedback devices can improve resuscitation quality during different modes of transportation. To assess the effect of real time automated feedback on the quality of resuscitation in an emergency transportation setting. Randomised cross-over trial. Medical University of Vienna, Vienna Municipal Ambulance Service and Helicopter Emergency Medical Service Unit (Christophorus Flugrettungsverein) in September 2007. European Resuscitation Council (ERC) certified health care professionals performing CPR in a flying helicopter and in a moving ambulance vehicle on a manikin with human-like chest properties. CPR sessions, with real time automated feedback as the intervention and standard CPR without feedback as control. Quality of chest compression during resuscitation. Feedback resulted in less deviation from ideal compression rate 100 min(-1) (9+/-9 min(-1), p<0.0001) with this effect becoming steadily larger over time. Applied work was less in the feedback group compared to controls (373+/-448 cm x compression; p<0.001). Feedback did not influence ideal compression depth significantly. There was some indication of a learning effect of the feedback device. Real time automated feedback improves certain aspects of CPR quality in flying helicopters and moving ambulance vehicles. The effect of feedback guidance was most pronounced for chest compression rate. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Combined contributions of feedforward and feedback inputs to bottom-up attention

PubMed Central

Khorsand, Peyman; Moore, Tirin; Soltani, Alireza

2015-01-01

In order to deal with a large amount of information carried by visual inputs entering the brain at any given point in time, the brain swiftly uses the same inputs to enhance processing in one part of visual field at the expense of the others. These processes, collectively called bottom-up attentional selection, are assumed to solely rely on feedforward processing of the external inputs, as it is implied by the nomenclature. Nevertheless, evidence from recent experimental and modeling studies points to the role of feedback in bottom-up attention. Here, we review behavioral and neural evidence that feedback inputs are important for the formation of signals that could guide attentional selection based on exogenous inputs. Moreover, we review results from a modeling study elucidating mechanisms underlying the emergence of these signals in successive layers of neural populations and how they depend on feedback from higher visual areas. We use these results to interpret and discuss more recent findings that can further unravel feedforward and feedback neural mechanisms underlying bottom-up attention. We argue that while it is descriptively useful to separate feedforward and feedback processes underlying bottom-up attention, these processes cannot be mechanistically separated into two successive stages as they occur at almost the same time and affect neural activity within the same brain areas using similar neural mechanisms. Therefore, understanding the interaction and integration of feedforward and feedback inputs is crucial for better understanding of bottom-up attention. PMID:25784883

Design and implementation of visual-haptic assistive control system for virtual rehabilitation exercise and teleoperation manipulation.

PubMed

Veras, Eduardo J; De Laurentis, Kathryn J; Dubey, Rajiv

2008-01-01

This paper describes the design and implementation of a control system that integrates visual and haptic information to give assistive force feedback through a haptic controller (Omni Phantom) to the user. A sensor-based assistive function and velocity scaling program provides force feedback that helps the user complete trajectory following exercises for rehabilitation purposes. This system also incorporates a PUMA robot for teleoperation, which implements a camera and a laser range finder, controlled in real time by a PC, were implemented into the system to help the user to define the intended path to the selected target. The real-time force feedback from the remote robot to the haptic controller is made possible by using effective multithreading programming strategies in the control system design and by novel sensor integration. The sensor-based assistant function concept applied to teleoperation as well as shared control enhances the motion range and manipulation capabilities of the users executing rehabilitation exercises such as trajectory following along a sensor-based defined path. The system is modularly designed to allow for integration of different master devices and sensors. Furthermore, because this real-time system is versatile the haptic component can be used separately from the telerobotic component; in other words, one can use the haptic device for rehabilitation purposes for cases in which assistance is needed to perform tasks (e.g., stroke rehab) and also for teleoperation with force feedback and sensor assistance in either supervisory or automatic modes.

Assisting Movement Training and Execution With Visual and Haptic Feedback.

PubMed

Ewerton, Marco; Rother, David; Weimar, Jakob; Kollegger, Gerrit; Wiemeyer, Josef; Peters, Jan; Maeda, Guilherme

2018-01-01

In the practice of motor skills in general, errors in the execution of movements may go unnoticed when a human instructor is not available. In this case, a computer system or robotic device able to detect movement errors and propose corrections would be of great help. This paper addresses the problem of how to detect such execution errors and how to provide feedback to the human to correct his/her motor skill using a general, principled methodology based on imitation learning. The core idea is to compare the observed skill with a probabilistic model learned from expert demonstrations. The intensity of the feedback is regulated by the likelihood of the model given the observed skill. Based on demonstrations, our system can, for example, detect errors in the writing of characters with multiple strokes. Moreover, by using a haptic device, the Haption Virtuose 6D, we demonstrate a method to generate haptic feedback based on a distribution over trajectories, which could be used as an auxiliary means of communication between an instructor and an apprentice. Additionally, given a performance measurement, the haptic device can help the human discover and perform better movements to solve a given task. In this case, the human first tries a few times to solve the task without assistance. Our framework, in turn, uses a reinforcement learning algorithm to compute haptic feedback, which guides the human toward better solutions.

Visual Feedback of Tongue Movement for Novel Speech Sound Learning

PubMed Central

Katz, William F.; Mehta, Sonya

2015-01-01

Pronunciation training studies have yielded important information concerning the processing of audiovisual (AV) information. Second language (L2) learners show increased reliance on bottom-up, multimodal input for speech perception (compared to monolingual individuals). However, little is known about the role of viewing one's own speech articulation processes during speech training. The current study investigated whether real-time, visual feedback for tongue movement can improve a speaker's learning of non-native speech sounds. An interactive 3D tongue visualization system based on electromagnetic articulography (EMA) was used in a speech training experiment. Native speakers of American English produced a novel speech sound (/ɖ/; a voiced, coronal, palatal stop) before, during, and after trials in which they viewed their own speech movements using the 3D model. Talkers' productions were evaluated using kinematic (tongue-tip spatial positioning) and acoustic (burst spectra) measures. The results indicated a rapid gain in accuracy associated with visual feedback training. The findings are discussed with respect to neural models for multimodal speech processing. PMID:26635571

Selective visual scaling of time-scale processes facilitates broadband learning of isometric force frequency tracking.

PubMed

King, Adam C; Newell, Karl M

2015-10-01

The experiment investigated the effect of selectively augmenting faster time scales of visual feedback information on the learning and transfer of continuous isometric force tracking tasks to test the generality of the self-organization of 1/f properties of force output. Three experimental groups tracked an irregular target pattern either under a standard fixed gain condition or with selectively enhancement in the visual feedback display of intermediate (4-8 Hz) or high (8-12 Hz) frequency components of the force output. All groups reduced tracking error over practice, with the error lowest in the intermediate scaling condition followed by the high scaling and fixed gain conditions, respectively. Selective visual scaling induced persistent changes across the frequency spectrum, with the strongest effect in the intermediate scaling condition and positive transfer to novel feedback displays. The findings reveal an interdependence of the timescales in the learning and transfer of isometric force output frequency structures consistent with 1/f process models of the time scales of motor output variability.

A hierarchy of timescales explains distinct effects of local inhibition of primary visual cortex and frontal eye fields

PubMed Central

Cocchi, Luca; Sale, Martin V; L Gollo, Leonardo; Bell, Peter T; Nguyen, Vinh T; Zalesky, Andrew; Breakspear, Michael; Mattingley, Jason B

2016-01-01

Within the primate visual system, areas at lower levels of the cortical hierarchy process basic visual features, whereas those at higher levels, such as the frontal eye fields (FEF), are thought to modulate sensory processes via feedback connections. Despite these functional exchanges during perception, there is little shared activity between early and late visual regions at rest. How interactions emerge between regions encompassing distinct levels of the visual hierarchy remains unknown. Here we combined neuroimaging, non-invasive cortical stimulation and computational modelling to characterize changes in functional interactions across widespread neural networks before and after local inhibition of primary visual cortex or FEF. We found that stimulation of early visual cortex selectively increased feedforward interactions with FEF and extrastriate visual areas, whereas identical stimulation of the FEF decreased feedback interactions with early visual areas. Computational modelling suggests that these opposing effects reflect a fast-slow timescale hierarchy from sensory to association areas. DOI: http://dx.doi.org/10.7554/eLife.15252.001 PMID:27596931

A hierarchy of timescales explains distinct effects of local inhibition of primary visual cortex and frontal eye fields.

PubMed

Cocchi, Luca; Sale, Martin V; L Gollo, Leonardo; Bell, Peter T; Nguyen, Vinh T; Zalesky, Andrew; Breakspear, Michael; Mattingley, Jason B

2016-09-06

Within the primate visual system, areas at lower levels of the cortical hierarchy process basic visual features, whereas those at higher levels, such as the frontal eye fields (FEF), are thought to modulate sensory processes via feedback connections. Despite these functional exchanges during perception, there is little shared activity between early and late visual regions at rest. How interactions emerge between regions encompassing distinct levels of the visual hierarchy remains unknown. Here we combined neuroimaging, non-invasive cortical stimulation and computational modelling to characterize changes in functional interactions across widespread neural networks before and after local inhibition of primary visual cortex or FEF. We found that stimulation of early visual cortex selectively increased feedforward interactions with FEF and extrastriate visual areas, whereas identical stimulation of the FEF decreased feedback interactions with early visual areas. Computational modelling suggests that these opposing effects reflect a fast-slow timescale hierarchy from sensory to association areas.

Hebbian learning in a model with dynamic rate-coded neurons: an alternative to the generative model approach for learning receptive fields from natural scenes.

PubMed

Hamker, Fred H; Wiltschut, Jan

2007-09-01

Most computational models of coding are based on a generative model according to which the feedback signal aims to reconstruct the visual scene as close as possible. We here explore an alternative model of feedback. It is derived from studies of attention and thus, probably more flexible with respect to attentive processing in higher brain areas. According to this model, feedback implements a gain increase of the feedforward signal. We use a dynamic model with presynaptic inhibition and Hebbian learning to simultaneously learn feedforward and feedback weights. The weights converge to localized, oriented, and bandpass filters similar as the ones found in V1. Due to presynaptic inhibition the model predicts the organization of receptive fields within the feedforward pathway, whereas feedback primarily serves to tune early visual processing according to the needs of the task.

Altered figure-ground perception in monkeys with an extra-striate lesion.

PubMed

Supèr, Hans; Lamme, Victor A F

2007-11-05

The visual system binds and segments the elements of an image into coherent objects and their surroundings. Recent findings demonstrate that primary visual cortex is involved in this process of figure-ground organization. In the primary visual cortex the late part of a neural response to a stimulus correlates with figure-ground segregation and perception. Such a late onset indicates an involvement of feedback projections from higher visual areas. To investigate the possible role of feedback in figure-ground perception we removed dorsal extra-striate areas of the monkey visual cortex. The findings show that figure-ground perception is reduced when the figure is presented in the lesioned hemifield and perception is normal when the figure appeared in the intact hemifield. In conclusion, our observations show the importance for recurrent processing in visual perception.

Eye-Hand Synergy and Intermittent Behaviors during Target-Directed Tracking with Visual and Non-visual Information

PubMed Central

Huang, Chien-Ting; Hwang, Ing-Shiou

2012-01-01

Visual feedback and non-visual information play different roles in tracking of an external target. This study explored the respective roles of the visual and non-visual information in eleven healthy volunteers who coupled the manual cursor to a rhythmically moving target of 0.5 Hz under three sensorimotor conditions: eye-alone tracking (EA), eye-hand tracking with visual feedback of manual outputs (EH tracking), and the same tracking without such feedback (EHM tracking). Tracking error, kinematic variables, and movement intermittency (saccade and speed pulse) were contrasted among tracking conditions. The results showed that EHM tracking exhibited larger pursuit gain, less tracking error, and less movement intermittency for the ocular plant than EA tracking. With the vision of manual cursor, EH tracking achieved superior tracking congruency of the ocular and manual effectors with smaller movement intermittency than EHM tracking, except that the rate precision of manual action was similar for both types of tracking. The present study demonstrated that visibility of manual consequences altered mutual relationships between movement intermittency and tracking error. The speed pulse metrics of manual output were linked to ocular tracking error, and saccade events were time-locked to the positional error of manual tracking during EH tracking. In conclusion, peripheral non-visual information is critical to smooth pursuit characteristics and rate control of rhythmic manual tracking. Visual information adds to eye-hand synchrony, underlying improved amplitude control and elaborate error interpretation during oculo-manual tracking. PMID:23236498

Processing reafferent and exafferent visual information for action and perception.

PubMed

Reichenbach, Alexandra; Diedrichsen, Jörn

2015-01-01

A recent study suggests that reafferent hand-related visual information utilizes a privileged, attention-independent processing channel for motor control. This process was termed visuomotor binding to reflect its proposed function: linking visual reafferences to the corresponding motor control centers. Here, we ask whether the advantage of processing reafferent over exafferent visual information is a specific feature of the motor processing stream or whether the improved processing also benefits the perceptual processing stream. Human participants performed a bimanual reaching task in a cluttered visual display, and one of the visual hand cursors could be displaced laterally during the movement. We measured the rapid feedback responses of the motor system as well as matched perceptual judgments of which cursor was displaced. Perceptual judgments were either made by watching the visual scene without moving or made simultaneously to the reaching tasks, such that the perceptual processing stream could also profit from the specialized processing of reafferent information in the latter case. Our results demonstrate that perceptual judgments in the heavily cluttered visual environment were improved when performed based on reafferent information. Even in this case, however, the filtering capability of the perceptual processing stream suffered more from the increasing complexity of the visual scene than the motor processing stream. These findings suggest partly shared and partly segregated processing of reafferent information for vision for motor control versus vision for perception.

The effect of step stool use and provider height on CPR quality during pediatric cardiac arrest: A simulation-based multicentre study.

PubMed

Cheng, Adam; Lin, Yiqun; Nadkarni, Vinay; Wan, Brandi; Duff, Jonathan; Brown, Linda; Bhanji, Farhan; Kessler, David; Tofil, Nancy; Hecker, Kent; Hunt, Elizabeth A

2018-01-01

We aimed to explore whether a) step stool use is associated with improved cardiopulmonary resuscitation (CPR) quality; b) provider adjusted height is associated with improved CPR quality; and if associations exist, c) determine whether just-in-time (JIT) CPR training and/or CPR visual feedback attenuates the effect of height and/or step stool use on CPR quality. We analysed data from a trial of simulated cardiac arrests with three study arms: No intervention; CPR visual feedback; and JIT CPR training. Step stool use was voluntary. We explored the association between 1) step stool use and CPR quality, and 2) provider adjusted height and CPR quality. Adjusted height was defined as provider height + 23 cm (if step stool was used). Below-average height participants were ≤ gender-specific average height; the remainder were above average height. We assessed for interaction between study arm and both adjusted height and step stool use. One hundred twenty-four subjects participated; 1,230 30-second epochs of CPR were analysed. Step stool use was associated with improved compression depth in below-average (female, p=0.007; male, p<0.001) and above-average (female, p=0.001; male, p<0.001) height providers. There is an association between adjusted height and compression depth (p<0.001). Visual feedback attenuated the effect of height (p=0.025) on compression depth; JIT training did not (p=0.918). Visual feedback and JIT training attenuated the effect of step stool use (p<0.001) on compression depth. Step stool use is associated with improved compression depth regardless of height. Increased provider height is associated with improved compression depth, with visual feedback attenuating the effects of height and step stool use.

A tactual display aid for primary flight training

NASA Technical Reports Server (NTRS)

Gilson, R. D.

1979-01-01

A means of flight instruction is discussed. In addition to verbal assistance, control feedback was continously presented via a nonvisual means utilizing touch. A kinesthetic-tactile (KT) display was used as a readout and tracking device for a computer generated signal of desired angle of attack during the approach and landing. Airspeed and glide path information was presented via KT or visual heads up display techniques. Performance with the heads up display of pitch information was shown to be significantly better than performance with the KT pitch display. Testing without the displays showed that novice pilots who had received tactile pitch error information performed both pitch and throttle control tasks significantly better than those who had received the same information from the visual heads up display of pitch during the test series of approaches to landing.

Feedback control and heat transfer measurements in a Rayleigh-Bénard convection cell

NASA Astrophysics Data System (ADS)

Vial, M.; Hernández, R. H.

2017-07-01

We report experimental results on the heat transfer and instability onset of a Rayleigh-Bénard convection cell of aspect ratios 6:3:1 filled with a high Prandtl aqueous solution of glycerol under feedback control. We investigate the transient and stationary response of both local temperature readings and heat transfer fluxes on the Rayleigh Bénard cell in both conductive and convective states when we perform two independent feedback control actions on both hot and cold walls. We evaluate the performance of both controllers to maintain a temperature gradient independently if the system is below or above the convection threshold. As the convection cell can be rotated at 180° about the shorter axis of the cell, it was possible to perform transitions between thermal conduction and convection regimes and vice versa under a constant temperature difference maintained by both independent controllers. The experimental setup provided an accurate measurement of the critical Rayleigh number and the evolution of the Nusselt number as a function of the Rayleigh number in the moderately supercritical regime (R a <1 04). Flow visualizations show a steady cellular convection pattern formed by 6 transverse rolls throughout the range of Rayleigh numbers.

Training voluntary motor suppression with real-time feedback of motor evoked potentials.

PubMed

Majid, D S Adnan; Lewis, Christina; Aron, Adam R

2015-05-01

Training people to suppress motor representations voluntarily could improve response control. We evaluated a novel training procedure of real-time feedback of motor evoked potentials (MEPs) generated by transcranial magnetic stimulation (TMS) over motor cortex. On each trial, a cue instructed participants to use a mental strategy to suppress a particular finger representation without overt movement. A single pulse of TMS was delivered over motor cortex, and an MEP-derived measure of hand motor excitability was delivered visually to the participant within 500 ms. In experiment 1, we showed that participants learned to reduce the excitability of a particular finger beneath baseline (selective motor suppression) within 30 min of practice. In experiment 2, we performed a double-blind study with 2 training groups (1 with veridical feedback and 1 with matched sham feedback) to show that selective motor suppression depends on the veridical feedback itself. Experiment 3 further demonstrated the importance of veridical feedback by showing that selective motor suppression did not arise from mere mental imagery, even when incentivized with reward. Thus participants can use real-time feedback of TMS-induced MEPs to discover an effective mental strategy for selective motor suppression. This high-temporal-resolution, trial-by-trial-feedback training method could be used to help people better control response tendencies and may serve as a potential therapy for motor disorders such as Tourette's and dystonia. Copyright © 2015 the American Physiological Society.

Tactile feedback is an effective instrument for the training of grasping with a prosthesis at low- and medium-force levels.

PubMed

De Nunzio, Alessandro Marco; Dosen, Strahinja; Lemling, Sabrina; Markovic, Marko; Schweisfurth, Meike Annika; Ge, Nan; Graimann, Bernhard; Falla, Deborah; Farina, Dario

2017-08-01

Grasping is a complex task routinely performed in an anticipatory (feedforward) manner, where sensory feedback is responsible for learning and updating the internal model of grasp dynamics. This study aims at evaluating whether providing a proportional tactile force feedback during the myoelectric control of a prosthesis facilitates learning a stable internal model of the prosthesis force control. Ten able-bodied subjects controlled a sensorized myoelectric prosthesis performing four blocks of consecutive grasps at three levels of target force (30, 50, and 70%), repeatedly closing the fully opened hand. In the first and third block, the subjects received tactile and visual feedback, respectively, while during the second and fourth block, the feedback was removed. The subjects also performed an additional block with no feedback 1 day after the training (Retest). The median and interquartile range of the generated forces was computed to assess the accuracy and precision of force control. The results demonstrated that the feedback was indeed an effective instrument for the training of prosthesis control. After the training, the subjects were still able to accurately generate the desired force for the low and medium target (30 and 50% of maximum force available in a prosthesis), despite the feedback being removed within the session and during the retest (low target force). However, the training was substantially less successful for high forces (70% of prosthesis maximum force), where subjects exhibited a substantial loss of accuracy as soon as the feedback was removed. The precision of control decreased with higher forces and it was consistent across conditions, determined by an intrinsic variability of repeated myoelectric grasping. This study demonstrated that the subject could rely on the tactile feedback to adjust the motor command to the prosthesis across trials. The subjects adjusted the mean level of muscle activation (accuracy), whereas the precision could not be modulated as it depends on the intrinsic myoelectric variability. They were also able to maintain the feedforward command even after the feedback was removed, demonstrating thereby a stable learning, but the retention depended on the level of the target force. This is an important insight into the role of feedback as an instrument for learning of anticipatory prosthesis force control.

Development of internal models and predictive abilities for visual tracking during childhood

PubMed Central

Ego, Caroline; Yüksel, Demet

2015-01-01

The prediction of the consequences of our own actions through internal models is an essential component of motor control. Previous studies showed improvement of anticipatory behaviors with age for grasping, drawing, and postural control. Since these actions require visual and proprioceptive feedback, these improvements might reflect both the development of internal models and the feedback control. In contrast, visual tracking of a temporarily invisible target gives specific markers of prediction and internal models for eye movements. Therefore, we recorded eye movements in 50 children (aged 5–19 yr) and in 10 adults, who were asked to pursue a visual target that is temporarily blanked. Results show that the youngest children (5–7 yr) have a general oculomotor behavior in this task, qualitatively similar to the one observed in adults. However, the overall performance of older subjects in terms of accuracy at target reappearance and variability in their behavior was much better than the youngest children. This late maturation of predictive mechanisms with age was reflected into the development of the accuracy of the internal models governing the synergy between the saccadic and pursuit systems with age. Altogether, we hypothesize that the maturation of the interaction between smooth pursuit and saccades that relies on internal models of the eye and target displacement is related to the continuous maturation of the cerebellum. PMID:26510757

Development of internal models and predictive abilities for visual tracking during childhood.

PubMed

Ego, Caroline; Yüksel, Demet; Orban de Xivry, Jean-Jacques; Lefèvre, Philippe

2016-01-01

The prediction of the consequences of our own actions through internal models is an essential component of motor control. Previous studies showed improvement of anticipatory behaviors with age for grasping, drawing, and postural control. Since these actions require visual and proprioceptive feedback, these improvements might reflect both the development of internal models and the feedback control. In contrast, visual tracking of a temporarily invisible target gives specific markers of prediction and internal models for eye movements. Therefore, we recorded eye movements in 50 children (aged 5-19 yr) and in 10 adults, who were asked to pursue a visual target that is temporarily blanked. Results show that the youngest children (5-7 yr) have a general oculomotor behavior in this task, qualitatively similar to the one observed in adults. However, the overall performance of older subjects in terms of accuracy at target reappearance and variability in their behavior was much better than the youngest children. This late maturation of predictive mechanisms with age was reflected into the development of the accuracy of the internal models governing the synergy between the saccadic and pursuit systems with age. Altogether, we hypothesize that the maturation of the interaction between smooth pursuit and saccades that relies on internal models of the eye and target displacement is related to the continuous maturation of the cerebellum. Copyright © 2016 the American Physiological Society.

A hybrid system for upper limb movement restoration in quadriplegics.

PubMed

Varoto, Renato; Barbarini, Elisa Signoreto; Cliquet, Alberto

2008-09-01

Generally, quadriplegic individuals have difficulties performing object manipulation. Toward satisfactory manipulation, reach and grasp movements must be performed with voluntary control, and for that, grasp force feedback is essential. A hybrid system aiming at partial upper limb sensory-motor restoration for quadriplegics was built. Such device is composed of an elbow dynamic orthosis that provides elbow flexion/extension (range was approximately from 20 degrees to 120 degrees , and average angular speed was approximately 15 degrees /s) with forearm support, a wrist static orthosis and neuromuscular electrical stimulation for grasping generation, and a glove with force sensors that allows grasping force feedback. The glove presents two user interface modes: visual by light emitting diodes or audio emitted by buzzer. Voice control of the entire system (elbow dynamic orthosis and electrical stimulator) is performed by the patient. The movements provided by the hybrid system, combined with the scapular and shoulder movements performed by the patient, can aid quadriplegic individuals in tasks that involve reach and grasp movements.

Examining a knowledge domain: Interactive visualization of the Geographic Information Science and Technology Body of Knowledge 1

NASA Astrophysics Data System (ADS)

Stowell, Marilyn Ruth

This research compared the effectiveness and performance of interactive visualizations of the GIS&T Body of Knowledge 1. The visualizations were created using Processing, and display the structure and content of the Body of Knowledge using various spatial layout methods: the Indented List, Tree Graph, treemap and Similarity Graph. The first three methods utilize the existing hierarchical structure of the BoK text, while the fourth method (Similarity Graph) serves as a jumping off point for exploring content-based visualizations of the BoK. The following questions have guided the framework of this research: (1) Which of the spatial layouts is most effective for completing tasks related to the GIS&T; BoK overall? How do they compare to each other in terms of performance? (2) Is one spatial layout significantly more or less effective than others for completing a particular cognitive task? (3) Is the user able to utilize the BoK as a basemap or reference system and make inferences based on BoK scorecard overlays? (4) Which design aspects of the interface assist in carrying out the survey objectives? Which design aspects of the application detract from fulfilling the objectives? To answer these questions, human subjects were recruited to participate in a survey, during which they were assigned a random spatial layout and were asked questions about the BoK based on their interaction with the visualization tool. 75 users were tested, 25 for each spatial layout. Statistical analysis revealed that there were no statistically significant differences between means for overall accuracy when comparing the three visualizations. In looking at individual questions, Tree Graph and Indented List yielded statistically significant higher scores for questions regarding the structure of the Body of Knowledge, as compared to the treemap. There was a significant strong positive correlation between the time taken to complete the survey and the final survey score. This correlation was particularly strong with treemap, possibly confirming the steeper learning curve with the more complex layout. Users were asked for feedback on the perceived "ease" of using the interface, and though few users said the interface was easy to use, there was a positive correlation between perceived "ease" and overall score. Qualitative feedback revealed that the external controls on the interface were not inviting to use, and the interface overall was not intuitive. Additional human subjects were recruited from the professional GIS community to participate in testing remotely. These results weren't significant due to small sample size, but helped to verify the feedback and results from the controlled testing.

Optic flow improves adaptability of spatiotemporal characteristics during split-belt locomotor adaptation with tactile stimulation

PubMed Central

Anthony Eikema, Diderik Jan A.; Chien, Jung Hung; Stergiou, Nicholas; Myers, Sara A.; Scott-Pandorf, Melissa M.; Bloomberg, Jacob J.; Mukherjee, Mukul

2015-01-01

Human locomotor adaptation requires feedback and feed-forward control processes to maintain an appropriate walking pattern. Adaptation may require the use of visual and proprioceptive input to decode altered movement dynamics and generate an appropriate response. After a person transfers from an extreme sensory environment and back, as astronauts do when they return from spaceflight, the prolonged period required for re-adaptation can pose a significant burden. In our previous paper, we showed that plantar tactile vibration during a split-belt adaptation task did not interfere with the treadmill adaptation however, larger overground transfer effects with a slower decay resulted. Such effects, in the absence of visual feedback (of motion) and perturbation of tactile feedback, is believed to be due to a higher proprioceptive gain because, in the absence of relevant external dynamic cues such as optic flow, reliance on body-based cues is enhanced during gait tasks through multisensory integration. In this study we therefore investigated the effect of optic flow on tactile stimulated split-belt adaptation as a paradigm to facilitate the sensorimotor adaptation process. Twenty healthy young adults, separated into two matched groups, participated in the study. All participants performed an overground walking trial followed by a split-belt treadmill adaptation protocol. The tactile group (TC) received vibratory plantar tactile stimulation only, whereas the virtual reality and tactile group (VRT) received an additional concurrent visual stimulation: a moving virtual corridor, inducing perceived self-motion. A post-treadmill overground trial was performed to determine adaptation transfer. Interlimb coordination of spatiotemporal and kinetic variables was quantified using symmetry indices, and analyzed using repeated-measures ANOVA. Marked changes of step length characteristics were observed in both groups during split-belt adaptation. Stance and swing time symmetry were similar in the two groups, suggesting that temporal parameters are not modified by optic flow. However, whereas the TC group displayed significant stance time asymmetries during the post-treadmill session, such aftereffects were absent in the VRT group. The results indicated that the enhanced transfer resulting from exposure to plantar cutaneous vibration during adaptation was alleviated by optic flow information. The presence of visual self-motion information may have reduced proprioceptive gain during learning. Thus, during overground walking, the learned proprioceptive split-belt pattern is more rapidly overridden by visual input due to its increased relative gain. The results suggest that when visual stimulation is provided during adaptive training, the system acquires the novel movement dynamics while maintaining the ability to flexibly adapt to different environments. PMID:26525712

Differential contributions of the superior and inferior parietal cortex to feedback versus feedforward control of tools.

PubMed

Macuga, Kristen L; Frey, Scott H

2014-05-15

Damage to the superior and/or inferior parietal lobules (SPL, IPL) (Sirigu et al., 1996) or cerebellum (Grealy and Lee, 2011) can selectively disrupt motor imagery, motivating the hypothesis that these regions participate in predictive (i.e., feedforward) control. If so, then the SPL, IPL, and cerebellum should show greater activity as the demands on feedforward control increase from visually-guided execution (closed-loop) to execution without visual feedback (open-loop) to motor imagery. Using fMRI and a Fitts' reciprocal aiming task with tools directed at targets in far space, we found that the SPL and cerebellum exhibited greater activity during closed-loop control. Conversely, open-loop and imagery conditions were associated with increased activity within the IPL and prefrontal areas. These results are consistent with a superior-to-inferior gradient in the representation of feedback-to-feedforward control within the posterior parietal cortex. Additionally, the anterior SPL displayed greater activity when aiming movements were performed with a stick vs. laser pointer. This may suggest that it is involved in the remapping of far into near (reachable) space (Maravita and Iriki, 2004), or in distalization of the end-effector from hand to stick (Arbib et al., 2009). Copyright © 2014 Elsevier Inc. All rights reserved.

A Comparison of Chest Compression Quality Delivered During On-Scene and Ground Transport Cardiopulmonary Resuscitation

PubMed Central

Russi, Christopher S.; Myers, Lucas A.; Kolb, Logan J.; Lohse, Christine M.; Hess, Erik P.; White, Roger D.

2016-01-01

Introduction American Heart Association (AHA) guidelines recommend cardiopulmonary resuscitation (CPR) chest compressions 1.5 to 2 inches (3.75–5 cm) deep at 100 to 120 per minute. Recent studies demonstrated that manual CPR by emergency medical services (EMS) personnel is substandard. We hypothesized that transport CPR quality is significantly worse than on-scene CPR quality. Methods We analyzed adult patients receiving on-scene and transport chest compressions from nine EMS sites across Minnesota and Wisconsin from May 2008 to July 2010. Two periods were analyzed: before and after visual feedback. CPR data were collected and exported with the Zoll M series monitor and a sternally placed accelerometer measuring chest compression rate and depth. We compared compression data with 2010 AHA guidelines and Zoll RescueNet Code Review software. CPR depth and rate were “above (deep),” “in,” or “below (shallow)” the target range according to AHA guidelines. We paired on-scene and transport data for each patient; paired proportions were compared with the nonparametric Wilcoxon signed rank test. Results In the pre-feedback period, we analyzed 105 of 140 paired cases (75.0%); in the post-feedback period, 35 of 140 paired cases (25.0%) were analyzed. The proportion of correct depths during on-scene compressions (median, 41.9%; interquartile range [IQR], 16.1–73.1) was higher compared to the paired transport proportion (median, 8.7%; IQR, 2.7–48.9). Proportions of on-scene median correct rates and transport median correct depths did not improve in the post-feedback period. Conclusion Transport chest compressions are significantly worse than on-scene compressions. Implementation of visual real-time feedback did not affect performance. PMID:27625733

Sensitivity to prediction error in reach adaptation

PubMed Central

Haith, Adrian M.; Harran, Michelle D.; Shadmehr, Reza

2012-01-01

It has been proposed that the brain predicts the sensory consequences of a movement and compares it to the actual sensory feedback. When the two differ, an error signal is formed, driving adaptation. How does an error in one trial alter performance in the subsequent trial? Here we show that the sensitivity to error is not constant but declines as a function of error magnitude. That is, one learns relatively less from large errors compared with small errors. We performed an experiment in which humans made reaching movements and randomly experienced an error in both their visual and proprioceptive feedback. Proprioceptive errors were created with force fields, and visual errors were formed by perturbing the cursor trajectory to create a visual error that was smaller, the same size, or larger than the proprioceptive error. We measured single-trial adaptation and calculated sensitivity to error, i.e., the ratio of the trial-to-trial change in motor commands to error size. We found that for both sensory modalities sensitivity decreased with increasing error size. A reanalysis of a number of previously published psychophysical results also exhibited this feature. Finally, we asked how the brain might encode sensitivity to error. We reanalyzed previously published probabilities of cerebellar complex spikes (CSs) and found that this probability declined with increasing error size. From this we posit that a CS may be representative of the sensitivity to error, and not error itself, a hypothesis that may explain conflicting reports about CSs and their relationship to error. PMID:22773782

Attribution of movement: Potential links between subjective reports of agency and output monitoring.

PubMed

Sugimori, Eriko; Asai, Tomohisa

2015-01-01

According to agency memory theory, individuals decide whether "I did it" based on a memory trace of "I am doing it". The purpose of this study was to validate the agency memory theory. To this end, several hand actions were individually presented as samples, and participants were asked to perform the sample action, observe the performance of that action by another person, or imagine performing the action. Online feedback received by the participants during the action was manipulated among the different conditions, and output monitoring, in which participants were asked whether they had performed each hand action, was conducted. The rate at which respondents thought that they themselves had performed the action was higher when visual feedback was unaltered than when it was altered (Experiment 1A), and this tendency was observed across all types of altered feedback (Experiment 1B). The observation of an action performed by the hand of another person did not increase the rate at which respondents thought that they themselves had performed the action unless the participants actually did perform the action (Experiments 2A and 2B). In Experiment 3, a relationship was observed between the subjective feeling that "I am the one who is causing an action" and the memory that "I did perform the action". These experiments support the hypothesis that qualitative information and sense of "self" are tagged in a memory trace and that such tags can be used as cues for judgements when the memory is related to the "self".

The effects of incentives on visual-spatial working memory in children with attention-deficit/hyperactivity disorder.

PubMed

Shiels, Keri; Hawk, Larry W; Lysczek, Cynthia L; Tannock, Rosemary; Pelham, William E; Spencer, Sarah V; Gangloff, Brian P; Waschbusch, Daniel A

2008-08-01

Working memory is one of several putative core neurocognitive processes in attention-deficit/hyperactivity disorder (ADHD). The present work seeks to determine whether visual-spatial working memory is sensitive to motivational incentives, a laboratory analogue of behavioral treatment. Participants were 21 children (ages 7-10) with a diagnosis of ADHD-combined type. Participants completed a computerized spatial span task designed to assess storage of visual-spatial information (forward span) and manipulation of the stored information (backward span). The spatial span task was completed twice on the same day, once with a performance-based incentive (trial-wise feedback and points redeemable for prizes) and once without incentives. Participants performed significantly better on the backward span when rewarded for correct responses, compared to the no incentive condition. However, incentives had no effect on performance during the forward span. These findings may suggest the use of motivational incentives improved manipulation, but not storage, of visual-spatial information among children with ADHD. Possible explanations for the differential incentive effects are discussed, including the possibility that incentives prevented a vigilance decrement as task difficulty and time on task increased.

Ultrasound visual feedback in articulation therapy following partial glossectomy.

PubMed

Blyth, Katrina M; Mccabe, Patricia; Madill, Catherine; Ballard, Kirrie J

2016-01-01

Disordered speech is common following treatment for tongue cancer, however there is insufficient high quality evidence to guide clinical decision making about treatment. This study investigated use of ultrasound tongue imaging as a visual feedback tool to guide tongue placement during articulation therapy with two participants following partial glossectomy. A Phase I multiple baseline design across behaviors was used to investigate therapeutic effect of ultrasound visual feedback during speech rehabilitation. Percent consonants correct and speech intelligibility at sentence level were used to measure acquisition, generalization and maintenance of speech skills for treated and untreated related phonemes, while unrelated phonemes were tested to demonstrate experimental control. Swallowing and oromotor measures were also taken to monitor change. Sentence intelligibility was not a sensitive measure of speech change, but both participants demonstrated significant change in percent consonants correct for treated phonemes. One participant also demonstrated generalization to non-treated phonemes. Control phonemes along with swallow and oromotor measures remained stable throughout the study. This study establishes therapeutic benefit of ultrasound visual feedback in speech rehabilitation following partial glossectomy. Readers will be able to explain why and how tongue cancer surgery impacts on articulation precision. Readers will also be able to explain the acquisition, generalization and maintenance effects in the study. Copyright © 2016. Published by Elsevier Inc.

A recurrent neural model for proto-object based contour integration and figure-ground segregation.

PubMed

Hu, Brian; Niebur, Ernst

2017-12-01

Visual processing of objects makes use of both feedforward and feedback streams of information. However, the nature of feedback signals is largely unknown, as is the identity of the neuronal populations in lower visual areas that receive them. Here, we develop a recurrent neural model to address these questions in the context of contour integration and figure-ground segregation. A key feature of our model is the use of grouping neurons whose activity represents tentative objects ("proto-objects") based on the integration of local feature information. Grouping neurons receive input from an organized set of local feature neurons, and project modulatory feedback to those same neurons. Additionally, inhibition at both the local feature level and the object representation level biases the interpretation of the visual scene in agreement with principles from Gestalt psychology. Our model explains several sets of neurophysiological results (Zhou et al. Journal of Neuroscience, 20(17), 6594-6611 2000; Qiu et al. Nature Neuroscience, 10(11), 1492-1499 2007; Chen et al. Neuron, 82(3), 682-694 2014), and makes testable predictions about the influence of neuronal feedback and attentional selection on neural responses across different visual areas. Our model also provides a framework for understanding how object-based attention is able to select both objects and the features associated with them.

Evaluating the Effectiveness of the Core Content of the Incredible Years with and without Visual Performance Feedback for Parents of Children with Autism

ERIC Educational Resources Information Center

Schultz, Tia R.

2011-01-01

Many children with autism display externalizing behavior due to challenges they face in the areas of communication, social skills and repetitive behavior or restricted interests. Parents have reported that it is difficult to know how to address these behaviors. Parent training programs have been found to increase parents' skills and decrease child…

Interactive Medical Volume Visualization for Surgical Operations

DTIC Science & Technology

2001-10-25

the preprocessing and processing stages, related medical brain tissues, which are skull, white matter, gray matter and pathology ( tumor ), are segmented ...from 12 or 16 bit data depths. NMR segmentation plays an important role in our work, because, classifying brain tissues from NMR slices requires an...performing segmentation of brain structures. Our segmentation process uses Self Organizing Feature Maps (SOFM) [12]. In SOM, on the contrary to Feedback

Undisturbed stance control in healthy adults is achieved differently along anteroposterior and mediolateral axes: evidence from visual feedback of various signals from center of pressure trajectories.

PubMed

Rougier, Patrice R

2009-05-01

Provided through the screen of a monitor, the participant's resultant center of pressure (CPRes) movements from a force platform device, modified the postural performance of a healthy individual. However, these effects could largely vary with the axis that researchers consider (mediolateral [ML] or anteroposterior [AP]), because they know these controls are involved in 2 distinct ankle and hip mechanisms. To demonstrate this organization, the author tested a group of healthy adults in several conditions that gave the whole or some part of the information in the CPRes displacements. Compared with the CPRes feedback, left and right plantar CP or body weight distribution feedback deteriorated the control of the vertically projected center of gravity (CGv) along the ML and AP axes, whose amplitudes increased, respectively. These data highlight the primary role of loading or unloading and pressure variations in the achievement of postural control along each ML or AP axis, respectively. It is interesting that merging these 2 pieces of information (CPRes displacements) helped participants optimize their postural performance.

A Robot Hand Testbed Designed for Enhancing Embodiment and Functional Neurorehabilitation of Body Schema in Subjects with Upper Limb Impairment or Loss

PubMed Central

Hellman, Randall B.; Chang, Eric; Tanner, Justin; Helms Tillery, Stephen I.; Santos, Veronica J.

2015-01-01

Many upper limb amputees experience an incessant, post-amputation “phantom limb pain” and report that their missing limbs feel paralyzed in an uncomfortable posture. One hypothesis is that efferent commands no longer generate expected afferent signals, such as proprioceptive feedback from changes in limb configuration, and that the mismatch of motor commands and visual feedback is interpreted as pain. Non-invasive therapeutic techniques for treating phantom limb pain, such as mirror visual feedback (MVF), rely on visualizations of postural changes. Advances in neural interfaces for artificial sensory feedback now make it possible to combine MVF with a high-tech “rubber hand” illusion, in which subjects develop a sense of embodiment with a fake hand when subjected to congruent visual and somatosensory feedback. We discuss clinical benefits that could arise from the confluence of known concepts such as MVF and the rubber hand illusion, and new technologies such as neural interfaces for sensory feedback and highly sensorized robot hand testbeds, such as the “BairClaw” presented here. Our multi-articulating, anthropomorphic robot testbed can be used to study proprioceptive and tactile sensory stimuli during physical finger–object interactions. Conceived for artificial grasp, manipulation, and haptic exploration, the BairClaw could also be used for future studies on the neurorehabilitation of somatosensory disorders due to upper limb impairment or loss. A remote actuation system enables the modular control of tendon-driven hands. The artificial proprioception system enables direct measurement of joint angles and tendon tensions while temperature, vibration, and skin deformation are provided by a multimodal tactile sensor. The provision of multimodal sensory feedback that is spatiotemporally consistent with commanded actions could lead to benefits such as reduced phantom limb pain, and increased prosthesis use due to improved functionality and reduced cognitive burden. PMID:25745391

A robot hand testbed designed for enhancing embodiment and functional neurorehabilitation of body schema in subjects with upper limb impairment or loss.

PubMed

Hellman, Randall B; Chang, Eric; Tanner, Justin; Helms Tillery, Stephen I; Santos, Veronica J

2015-01-01

Many upper limb amputees experience an incessant, post-amputation "phantom limb pain" and report that their missing limbs feel paralyzed in an uncomfortable posture. One hypothesis is that efferent commands no longer generate expected afferent signals, such as proprioceptive feedback from changes in limb configuration, and that the mismatch of motor commands and visual feedback is interpreted as pain. Non-invasive therapeutic techniques for treating phantom limb pain, such as mirror visual feedback (MVF), rely on visualizations of postural changes. Advances in neural interfaces for artificial sensory feedback now make it possible to combine MVF with a high-tech "rubber hand" illusion, in which subjects develop a sense of embodiment with a fake hand when subjected to congruent visual and somatosensory feedback. We discuss clinical benefits that could arise from the confluence of known concepts such as MVF and the rubber hand illusion, and new technologies such as neural interfaces for sensory feedback and highly sensorized robot hand testbeds, such as the "BairClaw" presented here. Our multi-articulating, anthropomorphic robot testbed can be used to study proprioceptive and tactile sensory stimuli during physical finger-object interactions. Conceived for artificial grasp, manipulation, and haptic exploration, the BairClaw could also be used for future studies on the neurorehabilitation of somatosensory disorders due to upper limb impairment or loss. A remote actuation system enables the modular control of tendon-driven hands. The artificial proprioception system enables direct measurement of joint angles and tendon tensions while temperature, vibration, and skin deformation are provided by a multimodal tactile sensor. The provision of multimodal sensory feedback that is spatiotemporally consistent with commanded actions could lead to benefits such as reduced phantom limb pain, and increased prosthesis use due to improved functionality and reduced cognitive burden.

OpinionSeer: interactive visualization of hotel customer feedback.

PubMed

Wu, Yingcai; Wei, Furu; Liu, Shixia; Au, Norman; Cui, Weiwei; Zhou, Hong; Qu, Huamin

2010-01-01

The rapid development of Web technology has resulted in an increasing number of hotel customers sharing their opinions on the hotel services. Effective visual analysis of online customer opinions is needed, as it has a significant impact on building a successful business. In this paper, we present OpinionSeer, an interactive visualization system that could visually analyze a large collection of online hotel customer reviews. The system is built on a new visualization-centric opinion mining technique that considers uncertainty for faithfully modeling and analyzing customer opinions. A new visual representation is developed to convey customer opinions by augmenting well-established scatterplots and radial visualization. To provide multiple-level exploration, we introduce subjective logic to handle and organize subjective opinions with degrees of uncertainty. Several case studies illustrate the effectiveness and usefulness of OpinionSeer on analyzing relationships among multiple data dimensions and comparing opinions of different groups. Aside from data on hotel customer feedback, OpinionSeer could also be applied to visually analyze customer opinions on other products or services.

Social reward shapes attentional biases.

PubMed

Anderson, Brian A

2016-01-01

Paying attention to stimuli that predict a reward outcome is important for an organism to survive and thrive. When visual stimuli are associated with tangible, extrinsic rewards such as money or food, these stimuli acquire high attentional priority and come to automatically capture attention. In humans and other primates, however, many behaviors are not motivated directly by such extrinsic rewards, but rather by the social feedback that results from performing those behaviors. In the present study, I examine whether positive social feedback can similarly influence attentional bias. The results show that stimuli previously associated with a high probability of positive social feedback elicit value-driven attentional capture, much like stimuli associated with extrinsic rewards. Unlike with extrinsic rewards, however, such stimuli also influence task-specific motivation. My findings offer a potential mechanism by which social reward shapes the information that we prioritize when perceiving the world around us.

Technology-Based Feedback and Its Efficacy in Improving Gait Parameters in Patients with Abnormal Gait: A Systematic Review

PubMed Central

Chamorro-Moriana, Gema; Moreno, Antonio José

2018-01-01

This systematic review synthesized and analyzed clinical findings related to the effectiveness of innovative technological feedback for tackling functional gait recovery. An electronic search of PUBMED, PEDro, WOS, CINAHL, and DIALNET was conducted from January 2011 to December 2016. The main inclusion criteria were: patients with modified or abnormal gait; application of technology-based feedback to deal with functional recovery of gait; any comparison between different kinds of feedback applied by means of technology, or any comparison between technological and non-technological feedback; and randomized controlled trials. Twenty papers were included. The populations were neurological patients (75%), orthopedic and healthy subjects. All participants were adults, bar one. Four studies used exoskeletons, 6 load platforms and 5 pressure sensors. The breakdown of the type of feedback used was as follows: 60% visual, 40% acoustic and 15% haptic. 55% used terminal feedback versus 65% simultaneous feedback. Prescriptive feedback was used in 60% of cases, while 50% used descriptive feedback. 62.5% and 58.33% of the trials showed a significant effect in improving step length and speed, respectively. Efficacy in improving other gait parameters such as balance or range of movement is observed in more than 75% of the studies with significant outcomes. Conclusion: Treatments based on feedback using innovative technology in patients with abnormal gait are mostly effective in improving gait parameters and therefore useful for the functional recovery of patients. The most frequently highlighted types of feedback were immediate visual feedback followed by terminal and immediate acoustic feedback. PMID:29316645

Technology-Based Feedback and Its Efficacy in Improving Gait Parameters in Patients with Abnormal Gait: A Systematic Review.

PubMed

Chamorro-Moriana, Gema; Moreno, Antonio José; Sevillano, José Luis

2018-01-06

This systematic review synthesized and analyzed clinical findings related to the effectiveness of innovative technological feedback for tackling functional gait recovery. An electronic search of PUBMED, PEDro, WOS, CINAHL, and DIALNET was conducted from January 2011 to December 2016. The main inclusion criteria were: patients with modified or abnormal gait; application of technology-based feedback to deal with functional recovery of gait; any comparison between different kinds of feedback applied by means of technology, or any comparison between technological and non-technological feedback; and randomized controlled trials. Twenty papers were included. The populations were neurological patients (75%), orthopedic and healthy subjects. All participants were adults, bar one. Four studies used exoskeletons, 6 load platforms and 5 pressure sensors. The breakdown of the type of feedback used was as follows: 60% visual, 40% acoustic and 15% haptic. 55% used terminal feedback versus 65% simultaneous feedback. Prescriptive feedback was used in 60% of cases, while 50% used descriptive feedback. 62.5% and 58.33% of the trials showed a significant effect in improving step length and speed, respectively. Efficacy in improving other gait parameters such as balance or range of movement is observed in more than 75% of the studies with significant outcomes. Treatments based on feedback using innovative technology in patients with abnormal gait are mostly effective in improving gait parameters and therefore useful for the functional recovery of patients. The most frequently highlighted types of feedback were immediate visual feedback followed by terminal and immediate acoustic feedback.

Firing-rate based network modeling of the dLGN circuit: Effects of cortical feedback on spatiotemporal response properties of relay cells.

PubMed

Mobarhan, Milad Hobbi; Halnes, Geir; Martínez-Cañada, Pablo; Hafting, Torkel; Fyhn, Marianne; Einevoll, Gaute T

2018-05-01

Visually evoked signals in the retina pass through the dorsal geniculate nucleus (dLGN) on the way to the visual cortex. This is however not a simple feedforward flow of information: there is a significant feedback from cortical cells back to both relay cells and interneurons in the dLGN. Despite four decades of experimental and theoretical studies, the functional role of this feedback is still debated. Here we use a firing-rate model, the extended difference-of-Gaussians (eDOG) model, to explore cortical feedback effects on visual responses of dLGN relay cells. For this model the responses are found by direct evaluation of two- or three-dimensional integrals allowing for fast and comprehensive studies of putative effects of different candidate organizations of the cortical feedback. Our analysis identifies a special mixed configuration of excitatory and inhibitory cortical feedback which seems to best account for available experimental data. This configuration consists of (i) a slow (long-delay) and spatially widespread inhibitory feedback, combined with (ii) a fast (short-delayed) and spatially narrow excitatory feedback, where (iii) the excitatory/inhibitory ON-ON connections are accompanied respectively by inhibitory/excitatory OFF-ON connections, i.e. following a phase-reversed arrangement. The recent development of optogenetic and pharmacogenetic methods has provided new tools for more precise manipulation and investigation of the thalamocortical circuit, in particular for mice. Such data will expectedly allow the eDOG model to be better constrained by data from specific animal model systems than has been possible until now for cat. We have therefore made the Python tool pyLGN which allows for easy adaptation of the eDOG model to new situations.

Investigations of the pathogenesis of acquired pendular nystagmus

NASA Technical Reports Server (NTRS)

Averbuch-Heller, L.; Zivotofsky, A. Z.; Das, V. E.; DiScenna, A. O.; Leigh, R. J.

1995-01-01

We investigated the pathogenesis of acquired pendular nystagmus (APN) in six patients, three of whom had multiple sclerosis. First, we tested the hypothesis that the oscillations of APN are due to a delay in visual feedback secondary, for example, to demyelination of the optic nerves. We manipulated the latency to onset of visually guided eye movements using an electronic technique that induces sinusoidal oscillations in normal subjects. This manipulation did not change the characteristics of the APN, but did superimpose lower-frequency oscillations similar to those induced in normal subjects. These results are consistent with current models for smooth (non-saccadic) eye movements, which predict that prolongation of visual feedback could not account for the high-frequency oscillations that often characterize APN. Secondly, we attempted to determine whether an increase in the gain of the visually-enhanced vestibulo-ocular reflex (VOR), produced by viewing a near target, was accompanied by a commensurate increase in the amplitude of APN. Increases in horizontal or vertical VOR gain during near viewing occurred in four patients, but only two of them showed a parallel increase in APN amplitude. On the other hand, APN amplitude decreased during viewing of the near target in the two patients who showed no change in VOR gain. Taken together, these data suggest that neither delayed visual feedback nor a disorder of central vestibular mechanisms is primarily responsible for APN. More likely, these ocular oscillations are produced by abnormalities of internal feedback circuits, such as the reciprocal connections between brainstem nuclei and cerebellum.

Binocular and Monocular Depth Cues in Online Feedback Control of 3-D Pointing Movement

PubMed Central

Hu, Bo; Knill, David C.

2012-01-01

Previous work has shown that humans continuously use visual feedback of the hand to control goal-directed movements online. In most studies, visual error signals were predominantly in the image plane and thus were available in an observer’s retinal image. We investigate how humans use visual feedback about finger depth provided by binocular and monocular depth cues to control pointing movements. When binocularly viewing a scene in which the hand movement was made in free space, subjects were about 60 ms slower in responding to perturbations in depth than in the image plane. When monocularly viewing a scene designed to maximize the available monocular cues to finger depth (motion, changing size and cast shadows), subjects showed no response to perturbations in depth. Thus, binocular cues from the finger are critical to effective online control of hand movements in depth. An optimal feedback controller that takes into account of the low peripheral stereoacuity and inherent ambiguity in cast shadows can explain the difference in response time in the binocular conditions and lack of response in monocular conditions. PMID:21724567

Integrating sentiment analysis and term associations with geo-temporal visualizations on customer feedback streams

NASA Astrophysics Data System (ADS)

Hao, Ming; Rohrdantz, Christian; Janetzko, Halldór; Keim, Daniel; Dayal, Umeshwar; Haug, Lars-Erik; Hsu, Mei-Chun

2012-01-01

Twitter currently receives over 190 million tweets (small text-based Web posts) and manufacturing companies receive over 10 thousand web product surveys a day, in which people share their thoughts regarding a wide range of products and their features. A large number of tweets and customer surveys include opinions about products and services. However, with Twitter being a relatively new phenomenon, these tweets are underutilized as a source for determining customer sentiments. To explore high-volume customer feedback streams, we integrate three time series-based visual analysis techniques: (1) feature-based sentiment analysis that extracts, measures, and maps customer feedback; (2) a novel idea of term associations that identify attributes, verbs, and adjectives frequently occurring together; and (3) new pixel cell-based sentiment calendars, geo-temporal map visualizations and self-organizing maps to identify co-occurring and influential opinions. We have combined these techniques into a well-fitted solution for an effective analysis of large customer feedback streams such as for movie reviews (e.g., Kung-Fu Panda) or web surveys (buyers).

A rodent brain-machine interface paradigm to study the impact of paraplegia on BMI performance.

PubMed

Bridges, Nathaniel R; Meyers, Michael; Garcia, Jonathan; Shewokis, Patricia A; Moxon, Karen A

2018-05-31

Most brain machine interfaces (BMI) focus on upper body function in non-injured animals, not addressing the lower limb functional needs of those with paraplegia. A need exists for a novel BMI task that engages the lower body and takes advantage of well-established rodent spinal cord injury (SCI) models to study methods to improve BMI performance. A tilt BMI task was designed that randomly applies different types of tilts to a platform, decodes the tilt type applied and rights the platform if the decoder correctly classifies the tilt type. The task was tested on female rats and is relatively natural such that it does not require the animal to learn a new skill. It is self-rewarding such that there is no need for additional rewards, eliminating food or water restriction, which can be especially hard on spinalized rats. Finally, task difficulty can be adjusted by making the tilt parameters. This novel BMI task bilaterally engages the cortex without visual feedback regarding limb position in space and animals learn to improve their performance both pre and post-SCI.Comparison with Existing Methods: Most BMI tasks primarily engage one hemisphere, are upper-body, rely heavily on visual feedback, do not perform investigations in animal models of SCI, and require nonnaturalistic extrinsic motivation such as water rewarding for performance improvement. Our task addresses these gaps. The BMI paradigm presented here will enable researchers to investigate the interaction of plasticity after SCI and plasticity during BMI training on performance. Copyright © 2018. Published by Elsevier B.V.

Alteration of a motor learning rule under mirror-reversal transformation does not depend on the amplitude of visual error.

PubMed

Kasuga, Shoko; Kurata, Makiko; Liu, Meigen; Ushiba, Junichi

2015-05-01

Human's sophisticated motor learning system paradoxically interferes with motor performance when visual information is mirror-reversed (MR), because normal movement error correction further aggravates the error. This error-increasing mechanism makes performing even a simple reaching task difficult, but is overcome by alterations in the error correction rule during the trials. To isolate factors that trigger learners to change the error correction rule, we manipulated the gain of visual angular errors when participants made arm-reaching movements with mirror-reversed visual feedback, and compared the rule alteration timing between groups with normal or reduced gain. Trial-by-trial changes in the visual angular error was tracked to explain the timing of the change in the error correction rule. Under both gain conditions, visual angular errors increased under the MR transformation, and suddenly decreased after 3-5 trials with increase. The increase became degressive at different amplitude between the two groups, nearly proportional to the visual gain. The findings suggest that the alteration of the error-correction rule is not dependent on the amplitude of visual angular errors, and possibly determined by the number of trials over which the errors increased or statistical property of the environment. The current results encourage future intensive studies focusing on the exact rule-change mechanism. Copyright © 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Feedback of personal retinal images appears to have a motivational impact in people with non-proliferative diabetic retinopathy and suboptimal HbA1c: findings of a pilot study.

PubMed

Rees, G; Lamoureux, E L; Nicolaou, T E; Hodgson, L A B; Weinman, J; Speight, J

2013-09-01

To conduct a pilot study to explore the potential impact of visual feedback of personal retinal images on diabetes outcomes. Twenty-five participants with non-proliferative diabetic retinopathy and suboptimal HbA(1c) (> 53 mmol/mol; > 7%) were randomized to receive visual feedback of their own retinal images or to a control group. At baseline and 3-month follow-up, HbA(1c), standard measures of beliefs, diabetes-related distress and self-care activities were assessed. In unadjusted models, relative to controls, the intervention group showed significantly greater improvement in HbA(1c) at 3-month follow-up (-0.6% vs. +0.3%, P < 0.01), as well as enhanced motivation to improve blood glucose management (P < 0.05). This small pilot study provides preliminary evidence that visual feedback of personal retinal images may offer a practical educational strategy for clinicians in eye care services to improve diabetes outcomes in non-target compliant patients. A fully powered randomized controlled trial is required to confirm these findings and determine the optimal use of feedback to produce sustained effects. © 2013 The Authors. Diabetic Medicine © 2013 Diabetes UK.

Perceptual learning through optimization of attentional weighting: human versus optimal Bayesian learner

NASA Technical Reports Server (NTRS)

Eckstein, Miguel P.; Abbey, Craig K.; Pham, Binh T.; Shimozaki, Steven S.

2004-01-01

Human performance in visual detection, discrimination, identification, and search tasks typically improves with practice. Psychophysical studies suggest that perceptual learning is mediated by an enhancement in the coding of the signal, and physiological studies suggest that it might be related to the plasticity in the weighting or selection of sensory units coding task relevant information (learning through attention optimization). We propose an experimental paradigm (optimal perceptual learning paradigm) to systematically study the dynamics of perceptual learning in humans by allowing comparisons to that of an optimal Bayesian algorithm and a number of suboptimal learning models. We measured improvement in human localization (eight-alternative forced-choice with feedback) performance of a target randomly sampled from four elongated Gaussian targets with different orientations and polarities and kept as a target for a block of four trials. The results suggest that the human perceptual learning can occur within a lapse of four trials (<1 min) but that human learning is slower and incomplete with respect to the optimal algorithm (23.3% reduction in human efficiency from the 1st-to-4th learning trials). The greatest improvement in human performance, occurring from the 1st-to-2nd learning trial, was also present in the optimal observer, and, thus reflects a property inherent to the visual task and not a property particular to the human perceptual learning mechanism. One notable source of human inefficiency is that, unlike the ideal observer, human learning relies more heavily on previous decisions than on the provided feedback, resulting in no human learning on trials following a previous incorrect localization decision. Finally, the proposed theory and paradigm provide a flexible framework for future studies to evaluate the optimality of human learning of other visual cues and/or sensory modalities.

Prosody production networks are modulated by sensory cues and social context.

PubMed

Klasen, Martin; von Marschall, Clara; Isman, Güldehen; Zvyagintsev, Mikhail; Gur, Ruben C; Mathiak, Klaus

2018-03-05

The neurobiology of emotional prosody production is not well investigated. In particular, the effects of cues and social context are not known. The present study sought to differentiate cued from free emotion generation and the effect of social feedback from a human listener. Online speech filtering enabled fMRI during prosodic communication in 30 participants. Emotional vocalizations were a) free, b) auditorily cued, c) visually cued, or d) with interactive feedback. In addition to distributed language networks, cued emotions increased activity in auditory and - in case of visual stimuli - visual cortex. Responses were larger in pSTG at the right hemisphere and the ventral striatum when participants were listened to and received feedback from the experimenter. Sensory, language, and reward networks contributed to prosody production and were modulated by cues and social context. The right pSTG is a central hub for communication in social interactions - in particular for interpersonal evaluation of vocal emotions.

Vibrotactile Feedbacks System for Assisting the Physically Impaired Persons for Easy Navigation

NASA Astrophysics Data System (ADS)

Safa, M.; Geetha, G.; Elakkiya, U.; Saranya, D.

2018-04-01

NAYAN architecture is for a visually impaired person to help for navigation. As well known, all visually impaired people desperately requires special requirements even to access services like the public transportation. This prototype system is a portable device; it is so easy to carry in any conduction to travel through a familiar and unfamiliar environment. The system consists of GPS receiver and it can get NEMA data through the satellite and it is provided to user's Smartphone through Arduino board. This application uses two vibrotactile feedbacks that will be placed in the left and right shoulder for vibration feedback, which gives information about the current location. The ultrasonic sensor is used for obstacle detection which is found in front of the visually impaired person. The Bluetooth modules connected with Arduino board is to send information to the user's mobile phone which it receives from GPS.

On the Adaptation of Pelvic Motion by Applying 3-dimensional Guidance Forces Using TPAD.

PubMed

Kang, Jiyeon; Vashista, Vineet; Agrawal, Sunil K

2017-09-01

Pelvic movement is important to human locomotion as the center of mass is located near the center of pelvis. Lateral pelvic motion plays a crucial role to shift the center of mass on the stance leg, while swinging the other leg and keeping the body balanced. In addition, vertical pelvic movement helps to reduce metabolic energy expenditure by exchanging potential and kinetic energy during the gait cycle. However, patient groups with cerebral palsy or stroke have excessive pelvic motion that leads to high energy expenditure. In addition, they have higher chances of falls as the center ofmass could deviate outside the base of support. In this paper, a novel control method is suggested using tethered pelvic assist device (TPAD) to teach subjects to walk with a specified target pelvic trajectory while walking on a treadmill. In this method, a force field is applied to the pelvis to guide it to move on a target trajectory and correctional forces are applied, if the pelvis motion has excessive deviations from the target trajectory. Three different experimentswith healthy subjects were conducted to teach them to walk on a new target pelvic trajectory with the presented control method. For all three experiments, the baseline trajectory of the pelvis was experimentally determined for each participating subject. To design a target pelvic trajectory which is different from the baseline, Experiment I scaled up the lateral component of the baseline pelvic trajectory, while Experiment II scaled down the lateral component of the baseline trajectory. For both Experiments I and II, the controller generated a 2-D force field in the transverse plane to provide the guidance force. In this paper, seven subjects were recruited for each experiment who walked on the treadmill with suggested control methods and visual feedback of their pelvic trajectory. The results show that the subjects were able to learn the target pelvic trajectory in each experiment and also retained the training effects after the completion of the experiment. In Experiment III, both lateral and vertical components of the pelvic trajectory were scaled down from the baseline trajectory. The force field was extended to three dimensions in order to correct the vertical pelvic movement as well. Three subgroups (force feedback alone, visual feedback alone, and both force and visual feedback) were recruited to understand the effects of force feedback and visual feedback alone to distinguish the results from Experiments I and II. The results showthat a trainingmethod that combines visual and force feedback is superior to the training methods with visual or force feedback alone. We believe that the present control strategy holds potential in training and correcting abnormal pelvic movements in different patient populations.

Hierarchical representation of shapes in visual cortex—from localized features to figural shape segregation

PubMed Central

Tschechne, Stephan; Neumann, Heiko

2014-01-01

Visual structures in the environment are segmented into image regions and those combined to a representation of surfaces and prototypical objects. Such a perceptual organization is performed by complex neural mechanisms in the visual cortex of primates. Multiple mutually connected areas in the ventral cortical pathway receive visual input and extract local form features that are subsequently grouped into increasingly complex, more meaningful image elements. Such a distributed network of processing must be capable to make accessible highly articulated changes in shape boundary as well as very subtle curvature changes that contribute to the perception of an object. We propose a recurrent computational network architecture that utilizes hierarchical distributed representations of shape features to encode surface and object boundary over different scales of resolution. Our model makes use of neural mechanisms that model the processing capabilities of early and intermediate stages in visual cortex, namely areas V1–V4 and IT. We suggest that multiple specialized component representations interact by feedforward hierarchical processing that is combined with feedback signals driven by representations generated at higher stages. Based on this, global configurational as well as local information is made available to distinguish changes in the object's contour. Once the outline of a shape has been established, contextual contour configurations are used to assign border ownership directions and thus achieve segregation of figure and ground. The model, thus, proposes how separate mechanisms contribute to distributed hierarchical cortical shape representation and combine with processes of figure-ground segregation. Our model is probed with a selection of stimuli to illustrate processing results at different processing stages. We especially highlight how modulatory feedback connections contribute to the processing of visual input at various stages in the processing hierarchy. PMID:25157228

Hierarchical representation of shapes in visual cortex-from localized features to figural shape segregation.

PubMed

Tschechne, Stephan; Neumann, Heiko

2014-01-01

Visual structures in the environment are segmented into image regions and those combined to a representation of surfaces and prototypical objects. Such a perceptual organization is performed by complex neural mechanisms in the visual cortex of primates. Multiple mutually connected areas in the ventral cortical pathway receive visual input and extract local form features that are subsequently grouped into increasingly complex, more meaningful image elements. Such a distributed network of processing must be capable to make accessible highly articulated changes in shape boundary as well as very subtle curvature changes that contribute to the perception of an object. We propose a recurrent computational network architecture that utilizes hierarchical distributed representations of shape features to encode surface and object boundary over different scales of resolution. Our model makes use of neural mechanisms that model the processing capabilities of early and intermediate stages in visual cortex, namely areas V1-V4 and IT. We suggest that multiple specialized component representations interact by feedforward hierarchical processing that is combined with feedback signals driven by representations generated at higher stages. Based on this, global configurational as well as local information is made available to distinguish changes in the object's contour. Once the outline of a shape has been established, contextual contour configurations are used to assign border ownership directions and thus achieve segregation of figure and ground. The model, thus, proposes how separate mechanisms contribute to distributed hierarchical cortical shape representation and combine with processes of figure-ground segregation. Our model is probed with a selection of stimuli to illustrate processing results at different processing stages. We especially highlight how modulatory feedback connections contribute to the processing of visual input at various stages in the processing hierarchy.

The adenosine triphosphate method as a quality control tool to assess 'cleanliness' of frequently touched hospital surfaces.

PubMed

Knape, L; Hambraeus, A; Lytsy, B

2015-10-01

The adenosine triphosphate (ATP) method is widely accepted as a quality control method to complement visual assessment, in the specifications of requirements, when purchasing cleaning contractors in Swedish hospitals. To examine whether the amount of biological load, as measured by ATP on frequently touched near-patient surfaces, had been reduced after an intervention; to evaluate the correlation between visual assessment and ATP levels on the same surfaces; to identify aspects of the performance of the ATP method as a tool in evaluating hospital cleanliness. A prospective intervention study in three phases was carried out in a medical ward and an intensive care unit (ICU) at a regional hospital in mid-Sweden between 2012 and 2013. Existing cleaning procedures were defined and baseline tests were sampled by visual inspection and ATP measurements of ten frequently touched surfaces in patients' rooms before and after intervention. The intervention consisted of educating nursing staff about the importance of hospital cleaning and direct feedback of ATP levels before and after cleaning. The mixed model showed a significant decrease in ATP levels after the intervention (P < 0.001). Relative light unit values were lower in the ICU. Cleanliness as judged by visual assessments improved. In the logistic regression analysis, there was a significant association between visual assessments and ATP levels. Direct feedback of ATP levels, together with education and introduction of written cleaning protocols, were effective tools to improve cleanliness. Visual assessment correlated with the level of ATP but the correlation was not absolute. The ATP method could serve as an educational tool for staff, but is not enough to assess hospital cleanliness in general as only a limited part of a large area is covered. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Impact of visual and somatosensory deprivation on dynamic balance in adolescent idiopathic scoliosis.

PubMed

Kuo, Fang-Chuan; Wang, Nai-Hwei; Hong, Chang-Zern

2010-11-01

A cross-sectional study of balance control in adolescents with idiopathic scoliosis (AIS). To investigate the impact of visual and somatosensory deprivation on the dynamic balance in AIS patients and to discuss electromyographic (EMG) and posture sway findings. Most studies focus on posture sway in quiet standing controls with little effort on examining muscle-activated patterns in dynamic standing controls. Twenty-two AIS patients and 22 age-matched normal subjects were studied. To understand how visual and somatosensory information could modulate standing balance, balance tests with the Biodex stability system were performed on a moving platform under 3 conditions: visual feedback provided (VF), eyes closed (EC), and standing on a sponge pad with visual feedback provided (SV). Muscular activities of bilateral lumbar multifidi, gluteus medii, and gastrocnemii muscles were recorded with a telemetry EMG system. AIS patients had normal balance index and amplitude and duration of EMG similar to those of normal subjects in the balance test. However, the onset latency of right gastrocnemius was earlier in AIS patients than in normal subjects. In addition, body-side asymmetry was noted on muscle strength and onset latency in AIS subjects. Under EC condition, lumbar multifidi, and gluteus medii activities were higher than those under SV and VF conditions (P < 0.05). Under SV condition, the medial-lateral tilting angle was less than that under VF and EC conditions. In addition, the active duration of right gluteus medius was shorter under SV condition (P < 0.05). The dynamic balance control is particularly disruptive under visual deprivation with increasing lumbar multifidi and gluteus medii activities for compensation. Sponge pad can cause decrease in frontal plane tilting and gluteus medii effort. The asymmetric muscle strength and onset timing are attributed to anatomic deformation as opposed to neurologic etiological factors.

Removing own-limb visual input using mixed reality (MR) produces a "telescoping" illusion in healthy individuals.

PubMed

Thøgersen, Mikkel; Hansen, John; Arendt-Nielsen, Lars; Flor, Herta; Petrini, Laura

2018-07-16

The purpose of the present study was to assess changes in body perception when visual feedback was removed from the hand and arm with the purpose of resembling the visual deprivation arising from amputation. The illusion was created by removing the visual feedback from the participants' own left forearm using a mixed reality (MR) and green screen environment. Thirty healthy persons (15 female) participated in the study. Each subject experienced two MR conditions, one with and one without visual feedback from the left hand, and a baseline condition with normal vision of the limb (no MR). Body perception was assessed using proprioceptive drift, questionnaires on body perception, and thermal sensitivity measures (cold, warm, heat pain and cold pain detection thresholds). The proprioceptive drift showed a significant shift of the tip of the index finger (p<0.001) towards the elbow in the illusion condition (mean drift: -3.71 cm). Self-report showed a significant decrease in ownership (p<0.001), shift in perceptual distortions, (e.g. "It feels as if my lower arm has become shorter") (p=0.025), and changes in sensations of the hand (tingling, tickling) (p=0.025). A significant decrease was also observed in cold detection threshold (p<0.001), i.e. the detection threshold was cooler than for the control conditions. The proprioceptive drift together with the self-reported questionnaire showed that the participants felt a proximal retraction of their limb, resembling the telescoping experienced by phantom limb patients. The study highlights the influence of missing visual feedback and its possible contribution to phantom limb phenomena. Copyright © 2018 Elsevier B.V. All rights reserved.

Effectiveness of glucose monitoring systems modified for the visually impaired.

PubMed

Bernbaum, M; Albert, S G; Brusca, S; McGinnis, J; Miller, D; Hoffmann, J W; Mooradian, A D

1993-10-01

To compare three glucose meters modified for use by individuals with diabetes and visual impairment regarding accuracy, precision, and clinical reliability. Ten subjects with diabetes and visual impairment performed self-monitoring of blood glucose using each of the three commercially available blood glucose meters modified for visually impaired users (the AccuChek Freedom [Boehringer Mannheim, Indianapolis, IN], the Diascan SVM [Home Diagnostics, Eatontown, NJ], and the One Touch [Lifescan, Milpitas, CA]). The meters were independently evaluated by a laboratory technologist for precision and accuracy determinations. Only two meters were acceptable with regard to laboratory precision (coefficient of variation < 10%)--the Accuchek and the One Touch. The Accuchek and the One Touch did not differ significantly with regard to laboratory estimates of accuracy. A great discrepancy of the clinical reliability results was observed between these two meters. The Accuchek maintained a high degree of reliability (y = 0.99X + 0.44, r = 0.97, P = 0.001). The visually impaired subjects were unable to perform reliable testing using the One Touch system because of a lack of appropriate tactile landmarks and auditory signals. In addition to laboratory assessments of glucose meters, monitoring systems designed for the visually impaired must include adequate tactile and audible feedback features to allow for the acquisition and placement of appropriate blood samples.

Functionally segregated neural substrates for arbitrary audiovisual paired-association learning.

PubMed

Tanabe, Hiroki C; Honda, Manabu; Sadato, Norihiro

2005-07-06

To clarify the neural substrates and their dynamics during crossmodal association learning, we conducted functional magnetic resonance imaging (MRI) during audiovisual paired-association learning of delayed matching-to-sample tasks. Thirty subjects were involved in the study; 15 performed an audiovisual paired-association learning task, and the remainder completed a control visuo-visual task. Each trial consisted of the successive presentation of a pair of stimuli. Subjects were asked to identify predefined audiovisual or visuo-visual pairs by trial and error. Feedback for each trial was given regardless of whether the response was correct or incorrect. During the delay period, several areas showed an increase in the MRI signal as learning proceeded: crossmodal activity increased in unimodal areas corresponding to visual or auditory areas, and polymodal responses increased in the occipitotemporal junction and parahippocampal gyrus. This pattern was not observed in the visuo-visual intramodal paired-association learning task, suggesting that crossmodal associations might be formed by binding unimodal sensory areas via polymodal regions. In both the audiovisual and visuo-visual tasks, the MRI signal in the superior temporal sulcus (STS) in response to the second stimulus and feedback peaked during the early phase of learning and then decreased, indicating that the STS might be key to the creation of paired associations, regardless of stimulus type. In contrast to the activity changes in the regions discussed above, there was constant activity in the frontoparietal circuit during the delay period in both tasks, implying that the neural substrates for the formation and storage of paired associates are distinct from working memory circuits.

Dormitory Residents Reduce Electricity Consumption when Exposed to Real-Time Visual Feedback and Incentives

ERIC Educational Resources Information Center

Petersen, John E.; Shunturov, Vladislav; Janda, Kathryn; Platt, Gavin; Weinberger, Kate

2007-01-01

Purpose: In residential buildings, personal choices influence electricity and water consumption. Prior studies indicate that information feedback can stimulate resource conservation. College dormitories provide an excellent venue for controlled study of the effects of feedback. The goal of this study is to assess how different resolutions of…

Performance monitoring for brain-computer-interface actions.

PubMed

Schurger, Aaron; Gale, Steven; Gozel, Olivia; Blanke, Olaf

2017-02-01

When presented with a difficult perceptual decision, human observers are able to make metacognitive judgements of subjective certainty. Such judgements can be made independently of and prior to any overt response to a sensory stimulus, presumably via internal monitoring. Retrospective judgements about one's own task performance, on the other hand, require first that the subject perform a task and thus could potentially be made based on motor processes, proprioceptive, and other sensory feedback rather than internal monitoring. With this dichotomy in mind, we set out to study performance monitoring using a brain-computer interface (BCI), with which subjects could voluntarily perform an action - moving a cursor on a computer screen - without any movement of the body, and thus without somatosensory feedback. Real-time visual feedback was available to subjects during training, but not during the experiment where the true final position of the cursor was only revealed after the subject had estimated where s/he thought it had ended up after 6s of BCI-based cursor control. During the first half of the experiment subjects based their assessments primarily on the prior probability of the end position of the cursor on previous trials. However, during the second half of the experiment subjects' judgements moved significantly closer to the true end position of the cursor, and away from the prior. This suggests that subjects can monitor task performance when the task is performed without overt movement of the body. Copyright © 2016 Elsevier Inc. All rights reserved.

Texture Segregation Causes Early Figure Enhancement and Later Ground Suppression in Areas V1 and V4 of Visual Cortex

PubMed Central

Poort, Jasper; Self, Matthew W.; van Vugt, Bram; Malkki, Hemi; Roelfsema, Pieter R.

2016-01-01

Segregation of images into figures and background is fundamental for visual perception. Cortical neurons respond more strongly to figural image elements than to background elements, but the mechanisms of figure–ground modulation (FGM) are only partially understood. It is unclear whether FGM in early and mid-level visual cortex is caused by an enhanced response to the figure, a suppressed response to the background, or both. We studied neuronal activity in areas V1 and V4 in monkeys performing a texture segregation task. We compared texture-defined figures with homogeneous textures and found an early enhancement of the figure representation, and a later suppression of the background. Across neurons, the strength of figure enhancement was independent of the strength of background suppression. We also examined activity in the different V1 layers. Both figure enhancement and ground suppression were strongest in superficial and deep layers and weaker in layer 4. The current–source density profiles suggested that figure enhancement was caused by stronger synaptic inputs in feedback-recipient layers 1, 2, and 5 and ground suppression by weaker inputs in these layers, suggesting an important role for feedback connections from higher level areas. These results provide new insights into the mechanisms for figure–ground organization. PMID:27522074

Probing sensorimotor integration during musical performance.

PubMed

Furuya, Shinichi; Furukawa, Yuta; Uehara, Kazumasa; Oku, Takanori

2018-03-10

An integration of afferent sensory information from the visual, auditory, and proprioceptive systems into execution and update of motor programs plays crucial roles in control and acquisition of skillful sequential movements in musical performance. However, conventional behavioral and neurophysiological techniques that have been applied to study simplistic motor behaviors limit elucidating online sensorimotor integration processes underlying skillful musical performance. Here, we propose two novel techniques that were developed to investigate the roles of auditory and proprioceptive feedback in piano performance. First, a closed-loop noninvasive brain stimulation system that consists of transcranial magnetic stimulation, a motion sensor, and a microcomputer enabled to assess time-varying cortical processes subserving auditory-motor integration during piano playing. Second, a force-field system capable of manipulating the weight of a piano key allowed for characterizing movement adaptation based on the feedback obtained, which can shed light on the formation of an internal representation of the piano. Results of neurophysiological and psychophysics experiments provided evidence validating these systems as effective means for disentangling computational and neural processes of sensorimotor integration in musical performance. © 2018 New York Academy of Sciences.

An architecture for rapid prototyping of control schemes for artificial ventricles.

PubMed

Ficola, Antonio; Pagnottelli, Stefano; Valigi, Paolo; Zoppitelli, Maurizio

2004-01-01

This paper presents an experimental system aimed at rapid prototyping of feedback control schemes for ventricular assist devices, and artificial ventricles in general. The system comprises a classical mock circulatory system, an actuated bellow-based ventricle chamber, and a software architecture for control schemes implementation and experimental data acquisition, visualization and storing. Several experiments have been carried out, showing good performance of ventricular pressure tracking control schemes.

Fiber optic tracheal detection device

NASA Astrophysics Data System (ADS)

Souhan, Brian E.; Nawn, Corinne D.; Shmel, Richard; Watts, Krista L.; Ingold, Kirk A.

2017-02-01

Poorly performed airway management procedures can lead to a wide variety of adverse events, such as laryngeal trauma, stenosis, cardiac arrest, hypoxemia, or death as in the case of failed airway management or intubation of the esophagus. Current methods for confirming tracheal placement, such as auscultation, direct visualization or capnography, may be subjective, compromised due to clinical presentation or require additional specialized equipment that is not always readily available during the procedure. Consequently, there exists a need for a non-visual detection mechanism for confirming successful airway placement that can give the provider rapid feedback during the procedure. Based upon our previously presented work characterizing the reflectance spectra of tracheal and esophageal tissue, we developed a fiber-optic prototype to detect the unique spectral characteristics of tracheal tissue. Device performance was tested by its ability to differentiate ex vivo samples of tracheal and esophageal tissue. Pig tissue samples were tested with the larynx, trachea and esophagus intact as well as excised and mounted on cork. The device positively detected tracheal tissue 18 out of 19 trials and 1 false positive out of 19 esophageal trials. Our proof of concept device shows great promise as a potential mechanism for rapid user feedback during airway management procedures to confirm tracheal placement. Ongoing studies will investigate device optimizations of the probe for more refined sensing and in vivo testing.

A pervasive visual-haptic framework for virtual delivery training.

PubMed

Abate, Andrea F; Acampora, Giovanni; Loia, Vincenzo; Ricciardi, Stefano; Vasilakos, Athanasios V

2010-03-01

Thanks to the advances of voltage regulator (VR) technologies and haptic systems, virtual simulators are increasingly becoming a viable alternative to physical simulators in medicine and surgery, though many challenges still remain. In this study, a pervasive visual-haptic framework aimed to the training of obstetricians and midwives to vaginal delivery is described. The haptic feedback is provided by means of two hand-based haptic devices able to reproduce force-feedbacks on fingers and arms, thus enabling a much more realistic manipulation respect to stylus-based solutions. The interactive simulation is not solely driven by an approximated model of complex forces and physical constraints but, instead, is approached by a formal modeling of the whole labor and of the assistance/intervention procedures performed by means of a timed automata network and applied to a parametrical 3-D model of the anatomy, able to mimic a wide range of configurations. This novel methodology is able to represent not only the sequence of the main events associated to either a spontaneous or to an operative childbirth process, but also to help in validating the manual intervention as the actions performed by the user during the simulation are evaluated according to established medical guidelines. A discussion on the first results as well as on the challenges still unaddressed is included.

The effect of force feedback on student reasoning about gravity, mass, force and motion

NASA Astrophysics Data System (ADS)

Bussell, Linda

The purpose of this study was to examine whether force feedback within a computer simulation had an effect on reasoning by fifth grade students about gravity, mass, force, and motion, concepts which can be difficult for learners to grasp. Few studies have been done on cognitive learning and haptic feedback, particularly with young learners, but there is an extensive base of literature on children's conceptions of science and a number of studies focus specifically on children's conceptions of force and motion. This case study used a computer-based paddleball simulation with guided inquiry as the primary stimulus. Within the simulation, the learner could adjust the mass of the ball and the gravitational force. The experimental group used the simulation with visual and force feedback; the control group used the simulation with visual feedback but without force feedback. The proposition was that there would be differences in reasoning between the experimental and control groups, with force feedback being helpful with concepts that are more obvious when felt. Participants were 34 fifth-grade students from three schools. Students completed a modal (visual, auditory, and haptic) learning preference assessment and a pretest. The sessions, including participant experimentation and interviews, were audio recorded and observed. The interviews were followed by a written posttest. These data were analyzed to determine whether there were differences based on treatment, learning style, demographics, prior gaming experience, force feedback experience, or prior knowledge. Work with the simulation, regardless of group, was found to increase students' understanding of key concepts. The experimental group appeared to benefit from the supplementary help that force feedback provided. Those in the experimental group scored higher on the posttest than those in the control group. The greatest difference between mean group scores was on a question concerning the effects of increased gravitational force.

Supporting Stroke Motor Recovery Through a Mobile Application: A Pilot Study.

PubMed

Lawson, Sonia; Tang, Ziying; Feng, Jinjuan

Neuroplasticity and motor learning are promoted with repetitive movement, appropriate challenge, and performance feedback. ARMStrokes, a smartphone application, incorporates these qualities to support motor recovery. Engaging exercises are easily accessible for improved compliance. In a multiple-case, mixed-methods pilot study, the potential of this technology for stroke motor recovery was examined. Exercises calibrated to the participant's skill level targeted forearm, elbow, and shoulder motions for a 6-wk protocol. Visual, auditory, and vibration feedback promoted self-assessment. Pre- and posttest data from 6 chronic stroke survivors who used the app in different ways (i.e., to measure active or passive motion, to track endurance) demonstrated improvements in accuracy of movements, fatigue, range of motion, and performance of daily activities. Statistically significant changes were not obtained with this pilot study. Further study on the efficacy of this technology is supported. Copyright © 2017 by the American Occupational Therapy Association, Inc.

Evaluating Effectiveness of Modeling Motion System Feedback in the Enhanced Hess Structural Model of the Human Operator

NASA Technical Reports Server (NTRS)

Zaychik, Kirill; Cardullo, Frank; George, Gary; Kelly, Lon C.

2009-01-01

In order to use the Hess Structural Model to predict the need for certain cueing systems, George and Cardullo significantly expanded it by adding motion feedback to the model and incorporating models of the motion system dynamics, motion cueing algorithm and a vestibular system. This paper proposes a methodology to evaluate effectiveness of these innovations by performing a comparison analysis of the model performance with and without the expanded motion feedback. The proposed methodology is composed of two stages. The first stage involves fine-tuning parameters of the original Hess structural model in order to match the actual control behavior recorded during the experiments at NASA Visual Motion Simulator (VMS) facility. The parameter tuning procedure utilizes a new automated parameter identification technique, which was developed at the Man-Machine Systems Lab at SUNY Binghamton. In the second stage of the proposed methodology, an expanded motion feedback is added to the structural model. The resulting performance of the model is then compared to that of the original one. As proposed by Hess, metrics to evaluate the performance of the models include comparison against the crossover models standards imposed on the crossover frequency and phase margin of the overall man-machine system. Preliminary results indicate the advantage of having the model of the motion system and motion cueing incorporated into the model of the human operator. It is also demonstrated that the crossover frequency and the phase margin of the expanded model are well within the limits imposed by the crossover model.

The role of shared visual information for joint action coordination.

PubMed

Vesper, Cordula; Schmitz, Laura; Safra, Lou; Sebanz, Natalie; Knoblich, Günther

2016-08-01

Previous research has identified a number of coordination processes that enable people to perform joint actions. But what determines which coordination processes joint action partners rely on in a given situation? The present study tested whether varying the shared visual information available to co-actors can trigger a shift in coordination processes. Pairs of participants performed a movement task that required them to synchronously arrive at a target from separate starting locations. When participants in a pair received only auditory feedback about the time their partner reached the target they held their movement duration constant to facilitate coordination. When they received additional visual information about each other's movements they switched to a fundamentally different coordination process, exaggerating the curvature of their movements to communicate their arrival time. These findings indicate that the availability of shared perceptual information is a major factor in determining how individuals coordinate their actions to obtain joint outcomes. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Design, development, and evaluation of an MRI-guided SMA spring-actuated neurosurgical robot

PubMed Central

Ho, Mingyen; Kim, Yeongjin; Cheng, Shing Shin; Gullapalli, Rao; Desai, Jaydev P.

2015-01-01

In this paper, we present our work on the development of a magnetic resonance imaging (MRI)-compatible Minimally Invasive Neurosurgical Intracranial Robot (MINIR) comprising of shape memory alloy (SMA) spring actuators and tendon-sheath mechanism. We present the detailed modeling and analysis along with experimental results of the characterization of SMA spring actuators. Furthermore, to demonstrate image-feedback control, we used the images obtained from a camera to control the motion of the robot so that eventually continuous MR images could be used in the future to control the robot motion. Since the image tracking algorithm may fail in some situations, we also developed a temperature feedback control scheme which served as a backup controller for the robot. Experimental results demonstrated that both image feedback and temperature feedback can be used to control the motion of MINIR. A series of MRI compatibility tests were performed on the robot and the experimental results demonstrated that the robot is MRI compatible and no significant visual image distortion was observed in the MR images during robot operation. PMID:26622075

Visually driven chaining of elementary swim patterns into a goal-directed motor sequence: a virtual reality study of zebrafish prey capture

PubMed Central

Trivedi, Chintan A.; Bollmann, Johann H.

2013-01-01

Prey capture behavior critically depends on rapid processing of sensory input in order to track, approach, and catch the target. When using vision, the nervous system faces the problem of extracting relevant information from a continuous stream of input in order to detect and categorize visible objects as potential prey and to select appropriate motor patterns for approach. For prey capture, many vertebrates exhibit intermittent locomotion, in which discrete motor patterns are chained into a sequence, interrupted by short periods of rest. Here, using high-speed recordings of full-length prey capture sequences performed by freely swimming zebrafish larvae in the presence of a single paramecium, we provide a detailed kinematic analysis of first and subsequent swim bouts during prey capture. Using Fourier analysis, we show that individual swim bouts represent an elementary motor pattern. Changes in orientation are directed toward the target on a graded scale and are implemented by an asymmetric tail bend component superimposed on this basic motor pattern. To further investigate the role of visual feedback on the efficiency and speed of this complex behavior, we developed a closed-loop virtual reality setup in which minimally restrained larvae recapitulated interconnected swim patterns closely resembling those observed during prey capture in freely moving fish. Systematic variation of stimulus properties showed that prey capture is initiated within a narrow range of stimulus size and velocity. Furthermore, variations in the delay and location of swim triggered visual feedback showed that the reaction time of secondary and later swims is shorter for stimuli that appear within a narrow spatio-temporal window following a swim. This suggests that the larva may generate an expectation of stimulus position, which enables accelerated motor sequencing if the expectation is met by appropriate visual feedback. PMID:23675322

In Flight Evaluation of Active Inceptor Force-Feel Characteristics and Handling Qualities

DTIC Science & Technology

2012-05-01

DEGRADED ACCEPTABLE Mitchell Aponso (1995) Watson Schroeder (1990) 0.75 lb/in 2.3 lb/in2.9 lb/in5.9 lb/in Side Stk - lon Side Stk - lat Center Stk Figure...vestibular feedback ( and respectively), and the visual error compensation ( ). A key feature of this approach is the modeling of proprioceptive...and vestibular feedback, and is the proportional component of the visual compensation strategy. At its core the fundamental concept of the HQSF

Processing speed in recurrent visual networks correlates with general intelligence.

PubMed

Jolij, Jacob; Huisman, Danielle; Scholte, Steven; Hamel, Ronald; Kemner, Chantal; Lamme, Victor A F

2007-01-08

Studies on the neural basis of general fluid intelligence strongly suggest that a smarter brain processes information faster. Different brain areas, however, are interconnected by both feedforward and feedback projections. Whether both types of connections or only one of the two types are faster in smarter brains remains unclear. Here we show, by measuring visual evoked potentials during a texture discrimination task, that general fluid intelligence shows a strong correlation with processing speed in recurrent visual networks, while there is no correlation with speed of feedforward connections. The hypothesis that a smarter brain runs faster may need to be refined: a smarter brain's feedback connections run faster.

Evolution of attention mechanisms for early visual processing

NASA Astrophysics Data System (ADS)

Müller, Thomas; Knoll, Alois

2011-03-01

Early visual processing as a method to speed up computations on visual input data has long been discussed in the computer vision community. The general target of a such approaches is to filter nonrelevant information from the costly higher-level visual processing algorithms. By insertion of this additional filter layer the overall approach can be speeded up without actually changing the visual processing methodology. Being inspired by the layered architecture of the human visual processing apparatus, several approaches for early visual processing have been recently proposed. Most promising in this field is the extraction of a saliency map to determine regions of current attention in the visual field. Such saliency can be computed in a bottom-up manner, i.e. the theory claims that static regions of attention emerge from a certain color footprint, and dynamic regions of attention emerge from connected blobs of textures moving in a uniform way in the visual field. Top-down saliency effects are either unconscious through inherent mechanisms like inhibition-of-return, i.e. within a period of time the attention level paid to a certain region automatically decreases if the properties of that region do not change, or volitional through cognitive feedback, e.g. if an object moves consistently in the visual field. These bottom-up and top-down saliency effects have been implemented and evaluated in a previous computer vision system for the project JAST. In this paper an extension applying evolutionary processes is proposed. The prior vision system utilized multiple threads to analyze the regions of attention delivered from the early processing mechanism. Here, in addition, multiple saliency units are used to produce these regions of attention. All of these saliency units have different parameter-sets. The idea is to let the population of saliency units create regions of attention, then evaluate the results with cognitive feedback and finally apply the genetic mechanism: mutation and cloning of the best performers and extinction of the worst performers considering computation of regions of attention. A fitness function can be derived by evaluating, whether relevant objects are found in the regions created. It can be seen from various experiments, that the approach significantly speeds up visual processing, especially regarding robust ealtime object recognition, compared to an approach not using saliency based preprocessing. Furthermore, the evolutionary algorithm improves the overall performance of the preprocessing system in terms of quality, as the system automatically and autonomously tunes the saliency parameters. The computational overhead produced by periodical clone/delete/mutation operations can be handled well within the realtime constraints of the experimental computer vision system. Nevertheless, limitations apply whenever the visual field does not contain any significant saliency information for some time, but the population still tries to tune the parameters - overfitting avoids generalization in this case and the evolutionary process may be reset by manual intervention.

Reliability and relative weighting of visual and nonvisual information for perceiving direction of self-motion during walking

PubMed Central

Saunders, Jeffrey A.

2014-01-01

Direction of self-motion during walking is indicated by multiple cues, including optic flow, nonvisual sensory cues, and motor prediction. I measured the reliability of perceived heading from visual and nonvisual cues during walking, and whether cues are weighted in an optimal manner. I used a heading alignment task to measure perceived heading during walking. Observers walked toward a target in a virtual environment with and without global optic flow. The target was simulated to be infinitely far away, so that it did not provide direct feedback about direction of self-motion. Variability in heading direction was low even without optic flow, with average RMS error of 2.4°. Global optic flow reduced variability to 1.9°–2.1°, depending on the structure of the environment. The small amount of variance reduction was consistent with optimal use of visual information. The relative contribution of visual and nonvisual information was also measured using cue conflict conditions. Optic flow specified a conflicting heading direction (±5°), and bias in walking direction was used to infer relative weighting. Visual feedback influenced heading direction by 16%–34% depending on scene structure, with more effect with dense motion parallax. The weighting of visual feedback was close to the predictions of an optimal integration model given the observed variability measures. PMID:24648194

Effects of Anisometropic Amblyopia on Visuomotor Behavior, Part 2: Visually Guided Reaching

PubMed Central

Niechwiej-Szwedo, Ewa; Goltz, Herbert C.; Chandrakumar, Manokaraananthan; Hirji, Zahra; Crawford, J. Douglas; Wong, Agnes M. F.

2016-01-01

Purpose The effects of impaired spatiotemporal vision in amblyopia on visuomotor skills have rarely been explored in detail. The goal of this study was to examine the influences of amblyopia on visually guided reaching. Methods Fourteen patients with anisometropic amblyopia and 14 control subjects were recruited. Participants executed reach-to-touch movements toward targets presented randomly 5° or 10° to the left or right of central fixation in three viewing conditions: binocular, monocular amblyopic eye, and monocular fellow eye viewing (left and right monocular viewing for control subjects). Visual feedback of the target was removed on 50% of the trials at the initiation of reaching. Results Reaching accuracy was comparable between patients and control subjects during all three viewing conditions. Patients’ reaching responses were slightly less precise during amblyopic eye viewing, but their precision was normal during binocular or fellow eye viewing. Reaching reaction time was not affected by amblyopia. The duration of the acceleration phase was longer in patients than in control subjects under all viewing conditions, whereas the duration of the deceleration phase was unaffected. Peak acceleration and peak velocity were also reduced in patients. Conclusions Amblyopia affects both the programming and the execution of visually guided reaching. The increased duration of the acceleration phase, as well as the reduced peak acceleration and peak velocity, might reflect a strategy or adaptation of feedforward/feedback control of the visuomotor system to compensate for degraded spatiotemporal vision in amblyopia, allowing patients to optimize their reaching performance. PMID:21051723

Attentional bias to pain and social threat in pediatric patients with functional abdominal pain and pain-free youth before and after performance evaluation.

PubMed

Beck, Joy E; Lipani, Tricia A; Baber, Kari F; Dufton, Lynette; Garber, Judy; Smith, Craig A; Walker, Lynn S

2011-05-01

This study investigated attentional biases for pain and social threat versus neutral stimuli in 54 youth with functional abdominal pain (FAP) and 53 healthy control subjects (ages 10 to 16 years). We assessed attentional bias using a visual probe detection task (PDT) that presented pain and social threat words in comparison to neutral words at conscious (1250 ms) and preconscious (20 ms) presentation rates. We administered the PDT before and after random assignment of participants to a laboratory stressor--failure versus success feedback regarding their performance on a challenging computer game. All analyses controlled for trait anxiety. At the conscious rate of stimulus presentation, FAP patients exhibited preferential attention toward pain compared with neutral stimuli and compared with the control group. FAP patients maintained preferential attention toward conscious pain stimuli after performance feedback in both failure and success conditions. At the preconscious rate of stimulus presentation, FAP patients' attention was neutral at baseline but increased significantly toward pain stimuli after performance feedback in both failure and success conditions. FAP patients' somatic symptoms increased in both failure and success conditions; control youth's somatic symptoms only increased after failure. Regarding social threat, neither FAP nor control youth exhibited attentional bias toward social threat compared with neutral stimuli at baseline, but both FAP and control youth in the failure condition significantly increased attention away from social threat after failure feedback. Results suggest that FAP patients preferentially attend to pain stimuli in conscious awareness. Moreover, performance evaluation may activate their preconscious attention to pain stimuli. Copyright © 2011 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Designing feedback to mitigate teen distracted driving: A social norms approach.

PubMed

Merrikhpour, Maryam; Donmez, Birsen

2017-07-01

The purpose of this research is to investigate teens' perceived social norms and whether providing normative information can reduce distracted driving behaviors among them. Parents are among the most important social referents for teens; they have significant influences on teens' driving behaviors, including distracted driving which significantly contributes to teens' crash risks. Social norms interventions have been successfully applied in various domains including driving; however, this approach is yet to be explored for mitigating driver distraction among teens. Forty teens completed a driving simulator experiment while performing a self-paced visual-manual secondary task in four between-subject conditions: a) social norms feedback that provided a report at the end of each drive on teens' distracted driving behavior, comparing their distraction engagement to their parent's, b) post-drive feedback that provided just the report on teens' distracted driving behavior without information on their parents, c) real-time feedback in the form of auditory warnings based on eyes of road-time, and d) no feedback as control. Questionnaires were administered to collect data on these teens' and their parents' self-reported engagement in driver distractions and the associated social norms. Social norms and real-time feedback conditions resulted in significantly smaller average off-road glance duration, rate of long (>2s) off-road glances, and standard deviation of lane position compared to no feedback. Further, social norms feedback decreased brake response time and percentage of time not looking at the road compared to no feedback. No major effect was observed for post-drive feedback. Questionnaire results suggest that teens appeared to overestimate parental norms, but no effect of feedback was found on their perceptions. Feedback systems that leverage social norms can help mitigate driver distraction among teens. Overall, both social norms and real-time feedback induced positive driving behaviors, with social norms feedback outperforming real-time feedback. Copyright © 2017 Elsevier Ltd. All rights reserved.

Corticocortical feedback increases the spatial extent of normalization.

PubMed

Nassi, Jonathan J; Gómez-Laberge, Camille; Kreiman, Gabriel; Born, Richard T

2014-01-01

Normalization has been proposed as a canonical computation operating across different brain regions, sensory modalities, and species. It provides a good phenomenological description of non-linear response properties in primary visual cortex (V1), including the contrast response function and surround suppression. Despite its widespread application throughout the visual system, the underlying neural mechanisms remain largely unknown. We recently observed that corticocortical feedback contributes to surround suppression in V1, raising the possibility that feedback acts through normalization. To test this idea, we characterized area summation and contrast response properties in V1 with and without feedback from V2 and V3 in alert macaques and applied a standard normalization model to the data. Area summation properties were well explained by a form of divisive normalization, which computes the ratio between a neuron's driving input and the spatially integrated activity of a "normalization pool." Feedback inactivation reduced surround suppression by shrinking the spatial extent of the normalization pool. This effect was independent of the gain modulation thought to mediate the influence of contrast on area summation, which remained intact during feedback inactivation. Contrast sensitivity within the receptive field center was also unaffected by feedback inactivation, providing further evidence that feedback participates in normalization independent of the circuit mechanisms involved in modulating contrast gain and saturation. These results suggest that corticocortical feedback contributes to surround suppression by increasing the visuotopic extent of normalization and, via this mechanism, feedback can play a critical role in contextual information processing.

Corticocortical feedback increases the spatial extent of normalization

PubMed Central

Nassi, Jonathan J.; Gómez-Laberge, Camille; Kreiman, Gabriel; Born, Richard T.

2014-01-01

Normalization has been proposed as a canonical computation operating across different brain regions, sensory modalities, and species. It provides a good phenomenological description of non-linear response properties in primary visual cortex (V1), including the contrast response function and surround suppression. Despite its widespread application throughout the visual system, the underlying neural mechanisms remain largely unknown. We recently observed that corticocortical feedback contributes to surround suppression in V1, raising the possibility that feedback acts through normalization. To test this idea, we characterized area summation and contrast response properties in V1 with and without feedback from V2 and V3 in alert macaques and applied a standard normalization model to the data. Area summation properties were well explained by a form of divisive normalization, which computes the ratio between a neuron's driving input and the spatially integrated activity of a “normalization pool.” Feedback inactivation reduced surround suppression by shrinking the spatial extent of the normalization pool. This effect was independent of the gain modulation thought to mediate the influence of contrast on area summation, which remained intact during feedback inactivation. Contrast sensitivity within the receptive field center was also unaffected by feedback inactivation, providing further evidence that feedback participates in normalization independent of the circuit mechanisms involved in modulating contrast gain and saturation. These results suggest that corticocortical feedback contributes to surround suppression by increasing the visuotopic extent of normalization and, via this mechanism, feedback can play a critical role in contextual information processing. PMID:24910596

When money is not enough: awareness, success, and variability in motor learning.

PubMed

Manley, Harry; Dayan, Peter; Diedrichsen, Jörn

2014-01-01

When performing a skill such as throwing a dart, many different combinations of joint motions suffice to hit the target. The motor system adapts rapidly to reduce bias in the desired outcome (i.e., the first-order moment of the error); however, the essence of skill is to produce movements with less variability (i.e., to reduce the second-order moment). It is easy to see how feedback about success or failure could sculpt performance to achieve this aim. However, it is unclear whether the dimensions responsible for success or failure need to be known explicitly by the subjects, or whether learning can proceed without explicit awareness of the movement parameters that need to change. Here, we designed a redundant, two-dimensional reaching task in which we could selectively manipulate task success and the variability of action outcomes, whilst also manipulating awareness of the dimension along which performance could be improved. Variability was manipulated either by amplifying natural errors, leaving the correlation between the executed movement and the visual feedback intact, or by adding extrinsic noise, decorrelating movement and feedback. We found that explicit, binary, feedback about success or failure was only sufficient for learning when participants were aware of the dimension along which motor behavior had to change. Without such awareness, learning was only present when extrinsic noise was added to the feedback, but not when task success or variability was manipulated in isolation; learning was also much slower. Our results highlight the importance of conscious awareness of the relevant dimension during motor learning, and suggest that higher-order moments of outcome signals are likely to play a significant role in skill learning in complex tasks.

The use of real-time ultrasound imaging for biofeedback of lumbar multifidus muscle contraction in healthy subjects.

PubMed

Van, Khai; Hides, Julie A; Richardson, Carolyn A

2006-12-01

Randomized controlled trial. To determine if the provision of visual biofeedback using real-time ultrasound imaging enhances the ability to activate the multifidus muscle. Increasingly clinicians are using real-time ultrasound as a form of biofeedback when re-educating muscle activation. The effectiveness of this form of biofeedback for the multifidus muscle has not been reported. Healthy subjects were randomly divided into groups that received different forms of biofeedback. All subjects received clinical instruction on how to activate the multifidus muscle isometrically prior to testing and verbal feedback regarding the amount of multifidus contraction, which occurred during 10 repetitions (acquisition phase). In addition, 1 group received visual biofeedback (watched the multifidus muscle contract) using real-time ultrasound imaging. All subjects were reassessed a week later (retention phase). Subjects from both groups improved their voluntary contraction of the multifidus muscle in the acquisition phase (P<.001) and the ability to recruit the multifidus muscle differed between groups (P<.05), with subjects in the group that received visual ultrasound biofeedback achieving greater improvements. In addition, the group that received visual ultrasound biofeedback retained their improvement in performance from week 1 to week 2 (P>.90), whereas the performance of the other group decreased (P<.05). Real-time ultrasound imaging can be used to provide visual biofeedback and improve performance and retention in the ability to activate the multifidus muscle in healthy subjects.

Aging and Sensory Substitution in a Virtual Navigation Task.

PubMed

Levy-Tzedek, S; Maidenbaum, S; Amedi, A; Lackner, J

2016-01-01

Virtual environments are becoming ubiquitous, and used in a variety of contexts-from entertainment to training and rehabilitation. Recently, technology for making them more accessible to blind or visually impaired users has been developed, by using sound to represent visual information. The ability of older individuals to interpret these cues has not yet been studied. In this experiment, we studied the effects of age and sensory modality (visual or auditory) on navigation through a virtual maze. We added a layer of complexity by conducting the experiment in a rotating room, in order to test the effect of the spatial bias induced by the rotation on performance. Results from 29 participants showed that with the auditory cues, it took participants a longer time to complete the mazes, they took a longer path length through the maze, they paused more, and had more collisions with the walls, compared to navigation with the visual cues. The older group took a longer time to complete the mazes, they paused more, and had more collisions with the walls, compared to the younger group. There was no effect of room rotation on the performance, nor were there any significant interactions among age, feedback modality and room rotation. We conclude that there is a decline in performance with age, and that while navigation with auditory cues is possible even at an old age, it presents more challenges than visual navigation.