Effects of Retinal Eccentricity on Human Manual Control

NASA Technical Reports Server (NTRS)

Popovici, Alexandru; Zaal, Peter M. T.

2017-01-01

This study investigated the effects of viewing a primary flight display at different retinal eccentricities on human manual control behavior and performance. Ten participants performed a pitch tracking task while looking at a simplified primary flight display at different horizontal and vertical retinal eccentricities, and with two different controlled dynamics. Tracking performance declined at higher eccentricity angles and participants behaved more nonlinearly. The visual error rate gain increased with eccentricity for single-integrator-like controlled dynamics, but decreased for double-integrator-like dynamics. Participants' visual time delay was up to 100 ms higher at the highest horizontal eccentricity compared to foveal viewing. Overall, vertical eccentricity had a larger impact than horizontal eccentricity on most of the human manual control parameters and performance. Results might be useful in the design of displays and procedures for critical flight conditions such as in an aerodynamic stall.

Human rather than ape-like orbital morphology allows much greater lateral visual field expansion with eye abduction

PubMed Central

Denion, Eric; Hitier, Martin; Levieil, Eric; Mouriaux, Frédéric

2015-01-01

While convergent, the human orbit differs from that of non-human apes in that its lateral orbital margin is significantly more rearward. This rearward position does not obstruct the additional visual field gained through eye motion. This additional visual field is therefore considered to be wider in humans than in non-human apes. A mathematical model was designed to quantify this difference. The mathematical model is based on published computed tomography data in the human neuro-ocular plane (NOP) and on additional anatomical data from 100 human skulls and 120 non-human ape skulls (30 gibbons; 30 chimpanzees / bonobos; 30 orangutans; 30 gorillas). It is used to calculate temporal visual field eccentricity values in the NOP first in the primary position of gaze then for any eyeball rotation value in abduction up to 45° and any lateral orbital margin position between 85° and 115° relative to the sagittal plane. By varying the lateral orbital margin position, the human orbit can be made “non-human ape-like”. In the Pan-like orbit, the orbital margin position (98.7°) was closest to the human orbit (107.1°). This modest 8.4° difference resulted in a large 21.1° difference in maximum lateral visual field eccentricity with eyeball abduction (Pan-like: 115°; human: 136.1°). PMID:26190625

Transcranial focused ultrasound stimulation of human primary visual cortex

NASA Astrophysics Data System (ADS)

Lee, Wonhye; Kim, Hyun-Chul; Jung, Yujin; Chung, Yong An; Song, In-Uk; Lee, Jong-Hwan; Yoo, Seung-Schik

2016-09-01

Transcranial focused ultrasound (FUS) is making progress as a new non-invasive mode of regional brain stimulation. Current evidence of FUS-mediated neurostimulation for humans has been limited to the observation of subjective sensory manifestations and electrophysiological responses, thus warranting the identification of stimulated brain regions. Here, we report FUS sonication of the primary visual cortex (V1) in humans, resulting in elicited activation not only from the sonicated brain area, but also from the network of regions involved in visual and higher-order cognitive processes (as revealed by simultaneous acquisition of blood-oxygenation-level-dependent functional magnetic resonance imaging). Accompanying phosphene perception was also reported. The electroencephalo graphic (EEG) responses showed distinct peaks associated with the stimulation. None of the participants showed any adverse effects from the sonication based on neuroimaging and neurological examinations. Retrospective numerical simulation of the acoustic profile showed the presence of individual variability in terms of the location and intensity of the acoustic focus. With exquisite spatial selectivity and capability for depth penetration, FUS may confer a unique utility in providing non-invasive stimulation of region-specific brain circuits for neuroscientific and therapeutic applications.

Attention Determines Contextual Enhancement versus Suppression in Human Primary Visual Cortex.

PubMed

Flevaris, Anastasia V; Murray, Scott O

2015-09-02

Neural responses in primary visual cortex (V1) depend on stimulus context in seemingly complex ways. For example, responses to an oriented stimulus can be suppressed when it is flanked by iso-oriented versus orthogonally oriented stimuli but can also be enhanced when attention is directed to iso-oriented versus orthogonal flanking stimuli. Thus the exact same contextual stimulus arrangement can have completely opposite effects on neural responses-in some cases leading to orientation-tuned suppression and in other cases leading to orientation-tuned enhancement. Here we show that stimulus-based suppression and enhancement of fMRI responses in humans depends on small changes in the focus of attention and can be explained by a model that combines feature-based attention with response normalization. Neurons in the primary visual cortex (V1) respond to stimuli within a restricted portion of the visual field, termed their "receptive field." However, neuronal responses can also be influenced by stimuli that surround a receptive field, although the nature of these contextual interactions and underlying neural mechanisms are debated. Here we show that the response in V1 to a stimulus in the same context can either be suppressed or enhanced depending on the focus of attention. We are able to explain the results using a simple computational model that combines two well established properties of visual cortical responses: response normalization and feature-based enhancement. Copyright © 2015 the authors 0270-6474/15/3512273-08$15.00/0.

Bioelectronic nose and its application to smell visualization.

PubMed

Ko, Hwi Jin; Park, Tai Hyun

2016-01-01

There have been many trials to visualize smell using various techniques in order to objectively express the smell because information obtained from the sense of smell in human is very subjective. So far, well-trained experts such as a perfumer, complex and large-scale equipment such as GC-MS, and an electronic nose have played major roles in objectively detecting and recognizing odors. Recently, an optoelectronic nose was developed to achieve this purpose, but some limitations regarding the sensitivity and the number of smells that can be visualized still persist. Since the elucidation of the olfactory mechanism, numerous researches have been accomplished for the development of a sensing device by mimicking human olfactory system. Engineered olfactory cells were constructed to mimic the human olfactory system, and the use of engineered olfactory cells for smell visualization has been attempted with the use of various methods such as calcium imaging, CRE reporter assay, BRET, and membrane potential assay; however, it is not easy to consistently control the condition of cells and it is impossible to detect low odorant concentration. Recently, the bioelectronic nose was developed, and much improved along with the improvement of nano-biotechnology. The bioelectronic nose consists of the following two parts: primary transducer and secondary transducer. Biological materials as a primary transducer improved the selectivity of the sensor, and nanomaterials as a secondary transducer increased the sensitivity. Especially, the bioelectronic noses using various nanomaterials combined with human olfactory receptors or nanovesicles derived from engineered olfactory cells have a potential which can detect almost all of the smells recognized by human because an engineered olfactory cell might be able to express any human olfactory receptor as well as can mimic human olfactory system. Therefore, bioelectronic nose will be a potent tool for smell visualization, but only if two technologies are completed. First, a multi-channel array-sensing system has to be applied for the integration of all of the olfactory receptors into a single chip for mimicking the performance of human nose. Second, the processing technique of the multi-channel system signals should be simultaneously established with the conversion of the signals to visual images. With the use of this latest sensing technology, the realization of a proper smell-visualization technology is expected in the near future.

Rethinking Visual Analytics for Streaming Data Applications

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

Crouser, R. Jordan; Franklin, Lyndsey; Cook, Kris

In the age of data science, the use of interactive information visualization techniques has become increasingly ubiquitous. From online scientific journals to the New York Times graphics desk, the utility of interactive visualization for both storytelling and analysis has become ever more apparent. As these techniques have become more readily accessible, the appeal of combining interactive visualization with computational analysis continues to grow. Arising out of a need for scalable, human-driven analysis, primary objective of visual analytics systems is to capitalize on the complementary strengths of human and machine analysis, using interactive visualization as a medium for communication between themore » two. These systems leverage developments from the fields of information visualization, computer graphics, machine learning, and human-computer interaction to support insight generation in areas where purely computational analyses fall short. Over the past decade, visual analytics systems have generated remarkable advances in many historically challenging analytical contexts. These include areas such as modeling political systems [Crouser et al. 2012], detecting financial fraud [Chang et al. 2008], and cybersecurity [Harrison et al. 2012]. In each of these contexts, domain expertise and human intuition is a necessary component of the analysis. This intuition is essential to building trust in the analytical products, as well as supporting the translation of evidence into actionable insight. In addition, each of these examples also highlights the need for scalable analysis. In each case, it is infeasible for a human analyst to manually assess the raw information unaided, and the communication overhead to divide the task between a large number of analysts makes simple parallelism intractable. Regardless of the domain, visual analytics tools strive to optimize the allocation of human analytical resources, and to streamline the sensemaking process on data that is massive, complex, incomplete, and uncertain in scenarios requiring human judgment.« less

Learning invariance from natural images inspired by observations in the primary visual cortex.

PubMed

Teichmann, Michael; Wiltschut, Jan; Hamker, Fred

2012-05-01

The human visual system has the remarkable ability to largely recognize objects invariant of their position, rotation, and scale. A good interpretation of neurobiological findings involves a computational model that simulates signal processing of the visual cortex. In part, this is likely achieved step by step from early to late areas of visual perception. While several algorithms have been proposed for learning feature detectors, only few studies at hand cover the issue of biologically plausible learning of such invariance. In this study, a set of Hebbian learning rules based on calcium dynamics and homeostatic regulations of single neurons is proposed. Their performance is verified within a simple model of the primary visual cortex to learn so-called complex cells, based on a sequence of static images. As a result, the learned complex-cell responses are largely invariant to phase and position.

Visual Perceptual Learning and Models.

PubMed

Dosher, Barbara; Lu, Zhong-Lin

2017-09-15

Visual perceptual learning through practice or training can significantly improve performance on visual tasks. Originally seen as a manifestation of plasticity in the primary visual cortex, perceptual learning is more readily understood as improvements in the function of brain networks that integrate processes, including sensory representations, decision, attention, and reward, and balance plasticity with system stability. This review considers the primary phenomena of perceptual learning, theories of perceptual learning, and perceptual learning's effect on signal and noise in visual processing and decision. Models, especially computational models, play a key role in behavioral and physiological investigations of the mechanisms of perceptual learning and for understanding, predicting, and optimizing human perceptual processes, learning, and performance. Performance improvements resulting from reweighting or readout of sensory inputs to decision provide a strong theoretical framework for interpreting perceptual learning and transfer that may prove useful in optimizing learning in real-world applications.

Advanced Video Activity Analytics (AVAA): Human Factors Evaluation

DTIC Science & Technology

2015-05-01

video, and 3) creating and saving annotations (Fig. 11). (The logging program was updated after the pilot to also capture search clicks.) Playing and... visual search task and the auditory task together and thus automatically focused on the visual task. Alternatively, the operator may have intentionally...affect performance on the primary task; however, in the current test there was no apparent effect on the operator’s performance in the visual search task

Primary Visual Cortex as a Saliency Map: A Parameter-Free Prediction and Its Test by Behavioral Data

PubMed Central

Zhaoping, Li; Zhe, Li

2015-01-01

It has been hypothesized that neural activities in the primary visual cortex (V1) represent a saliency map of the visual field to exogenously guide attention. This hypothesis has so far provided only qualitative predictions and their confirmations. We report this hypothesis’ first quantitative prediction, derived without free parameters, and its confirmation by human behavioral data. The hypothesis provides a direct link between V1 neural responses to a visual location and the saliency of that location to guide attention exogenously. In a visual input containing many bars, one of them saliently different from all the other bars which are identical to each other, saliency at the singleton’s location can be measured by the shortness of the reaction time in a visual search for singletons. The hypothesis predicts quantitatively the whole distribution of the reaction times to find a singleton unique in color, orientation, and motion direction from the reaction times to find other types of singletons. The prediction matches human reaction time data. A requirement for this successful prediction is a data-motivated assumption that V1 lacks neurons tuned simultaneously to color, orientation, and motion direction of visual inputs. Since evidence suggests that extrastriate cortices do have such neurons, we discuss the possibility that the extrastriate cortices play no role in guiding exogenous attention so that they can be devoted to other functions like visual decoding and endogenous attention. PMID:26441341

Feedforward and recurrent processing in scene segmentation: electroencephalography and functional magnetic resonance imaging.

PubMed

Scholte, H Steven; Jolij, Jacob; Fahrenfort, Johannes J; Lamme, Victor A F

2008-11-01

In texture segregation, an example of scene segmentation, we can discern two different processes: texture boundary detection and subsequent surface segregation [Lamme, V. A. F., Rodriguez-Rodriguez, V., & Spekreijse, H. Separate processing dynamics for texture elements, boundaries and surfaces in primary visual cortex of the macaque monkey. Cerebral Cortex, 9, 406-413, 1999]. Neural correlates of texture boundary detection have been found in monkey V1 [Sillito, A. M., Grieve, K. L., Jones, H. E., Cudeiro, J., & Davis, J. Visual cortical mechanisms detecting focal orientation discontinuities. Nature, 378, 492-496, 1995; Grosof, D. H., Shapley, R. M., & Hawken, M. J. Macaque-V1 neurons can signal illusory contours. Nature, 365, 550-552, 1993], but whether surface segregation occurs in monkey V1 [Rossi, A. F., Desimone, R., & Ungerleider, L. G. Contextual modulation in primary visual cortex of macaques. Journal of Neuroscience, 21, 1698-1709, 2001; Lamme, V. A. F. The neurophysiology of figure ground segregation in primary visual-cortex. Journal of Neuroscience, 15, 1605-1615, 1995], and whether boundary detection or surface segregation signals can also be measured in human V1, is more controversial [Kastner, S., De Weerd, P., & Ungerleider, L. G. Texture segregation in the human visual cortex: A functional MRI study. Journal of Neurophysiology, 83, 2453-2457, 2000]. Here we present electroencephalography (EEG) and functional magnetic resonance imaging data that have been recorded with a paradigm that makes it possible to differentiate between boundary detection and scene segmentation in humans. In this way, we were able to show with EEG that neural correlates of texture boundary detection are first present in the early visual cortex around 92 msec and then spread toward the parietal and temporal lobes. Correlates of surface segregation first appear in temporal areas (around 112 msec) and from there appear to spread to parietal, and back to occipital areas. After 208 msec, correlates of surface segregation and boundary detection also appear in more frontal areas. Blood oxygenation level-dependent magnetic resonance imaging results show correlates of boundary detection and surface segregation in all early visual areas including V1. We conclude that texture boundaries are detected in a feedforward fashion and are represented at increasing latencies in higher visual areas. Surface segregation, on the other hand, is represented in "reverse hierarchical" fashion and seems to arise from feedback signals toward early visual areas such as V1.

The coupling of cerebral blood flow and oxygen metabolism with brain activation is similar for simple and complex stimuli in human primary visual cortex.

PubMed

Griffeth, Valerie E M; Simon, Aaron B; Buxton, Richard B

2015-01-01

Quantitative functional MRI (fMRI) experiments to measure blood flow and oxygen metabolism coupling in the brain typically rely on simple repetitive stimuli. Here we compared such stimuli with a more naturalistic stimulus. Previous work on the primary visual cortex showed that direct attentional modulation evokes a blood flow (CBF) response with a relatively large oxygen metabolism (CMRO2) response in comparison to an unattended stimulus, which evokes a much smaller metabolic response relative to the flow response. We hypothesized that a similar effect would be associated with a more engaging stimulus, and tested this by measuring the primary human visual cortex response to two contrast levels of a radial flickering checkerboard in comparison to the response to free viewing of brief movie clips. We did not find a significant difference in the blood flow-metabolism coupling (n=%ΔCBF/%ΔCMRO2) between the movie stimulus and the flickering checkerboards employing two different analysis methods: a standard analysis using the Davis model and a new analysis using a heuristic model dependent only on measured quantities. This finding suggests that in the primary visual cortex a naturalistic stimulus (in comparison to a simple repetitive stimulus) is either not sufficient to provoke a change in flow-metabolism coupling by attentional modulation as hypothesized, that the experimental design disrupted the cognitive processes underlying the response to a more natural stimulus, or that the technique used is not sensitive enough to detect a small difference. Copyright © 2014 Elsevier Inc. All rights reserved.

Neural codes of seeing architectural styles

PubMed Central

Choo, Heeyoung; Nasar, Jack L.; Nikrahei, Bardia; Walther, Dirk B.

2017-01-01

Images of iconic buildings, such as the CN Tower, instantly transport us to specific places, such as Toronto. Despite the substantial impact of architectural design on people’s visual experience of built environments, we know little about its neural representation in the human brain. In the present study, we have found patterns of neural activity associated with specific architectural styles in several high-level visual brain regions, but not in primary visual cortex (V1). This finding suggests that the neural correlates of the visual perception of architectural styles stem from style-specific complex visual structure beyond the simple features computed in V1. Surprisingly, the network of brain regions representing architectural styles included the fusiform face area (FFA) in addition to several scene-selective regions. Hierarchical clustering of error patterns further revealed that the FFA participated to a much larger extent in the neural encoding of architectural styles than entry-level scene categories. We conclude that the FFA is involved in fine-grained neural encoding of scenes at a subordinate-level, in our case, architectural styles of buildings. This study for the first time shows how the human visual system encodes visual aspects of architecture, one of the predominant and longest-lasting artefacts of human culture. PMID:28071765

Neural codes of seeing architectural styles.

PubMed

Choo, Heeyoung; Nasar, Jack L; Nikrahei, Bardia; Walther, Dirk B

2017-01-10

Images of iconic buildings, such as the CN Tower, instantly transport us to specific places, such as Toronto. Despite the substantial impact of architectural design on people's visual experience of built environments, we know little about its neural representation in the human brain. In the present study, we have found patterns of neural activity associated with specific architectural styles in several high-level visual brain regions, but not in primary visual cortex (V1). This finding suggests that the neural correlates of the visual perception of architectural styles stem from style-specific complex visual structure beyond the simple features computed in V1. Surprisingly, the network of brain regions representing architectural styles included the fusiform face area (FFA) in addition to several scene-selective regions. Hierarchical clustering of error patterns further revealed that the FFA participated to a much larger extent in the neural encoding of architectural styles than entry-level scene categories. We conclude that the FFA is involved in fine-grained neural encoding of scenes at a subordinate-level, in our case, architectural styles of buildings. This study for the first time shows how the human visual system encodes visual aspects of architecture, one of the predominant and longest-lasting artefacts of human culture.

Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex.

PubMed

Scott, Gregory D; Karns, Christina M; Dow, Mark W; Stevens, Courtney; Neville, Helen J

2014-01-01

Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anatomical normalization across participants were limited by inter-subject variability of Heschl's gyrus. In addition to reorganized auditory cortex (cross-modal plasticity), a second gap in our understanding is the contribution of altered modality-specific cortices (visual intramodal plasticity in this case), as well as supramodal and multisensory cortices, especially when target detection is required across contrasts. Here we address these gaps by comparing fMRI signal change for peripheral vs. perifoveal visual stimulation (11-15° vs. 2-7°) in congenitally deaf and hearing participants in a blocked experimental design with two analytical approaches: a Heschl's gyrus region of interest analysis and a whole brain analysis. Our results using individually-defined primary auditory cortex (Heschl's gyrus) indicate that fMRI signal change for more peripheral stimuli was greater than perifoveal in deaf but not in hearing participants. Whole-brain analyses revealed differences between deaf and hearing participants for peripheral vs. perifoveal visual processing in extrastriate visual cortex including primary auditory cortex, MT+/V5, superior-temporal auditory, and multisensory and/or supramodal regions, such as posterior parietal cortex (PPC), frontal eye fields, anterior cingulate, and supplementary eye fields. Overall, these data demonstrate the contribution of neuroplasticity in multiple systems including primary auditory cortex, supramodal, and multisensory regions, to altered visual processing in congenitally deaf adults.

Expression of m1-type muscarinic acetylcholine receptors by parvalbumin-immunoreactive neurons in the primary visual cortex: a comparative study of rat, guinea pig, ferret, macaque, and human.

PubMed

Disney, Anita A; Reynolds, John H

2014-04-01

Cholinergic neuromodulation is a candidate mechanism for aspects of arousal and attention in mammals. We have reported previously that cholinergic modulation in the primary visual cortex (V1) of the macaque monkey is strongly targeted toward GABAergic interneurons, and in particular that the vast majority of parvalbumin-immunoreactive (PV) neurons in macaque V1 express the m1-type (pirenzepine-sensitive, Gq-coupled) muscarinic ACh receptor (m1AChR). In contrast, previous physiological data indicates that PV neurons in rats rarely express pirenzepine-sensitive muscarinic AChRs. To examine further this apparent species difference in the cholinergic effectors for the primary visual cortex, we have conducted a comparative study of the expression of m1AChRs by PV neurons in V1 of rats, guinea pigs, ferrets, macaques, and humans. We visualize PV- and mAChR-immunoreactive somata by dual-immunofluorescence confocal microscopy and find that the species differences are profound; the vast majority (>75%) of PV-ir neurons in macaques, humans, and guinea pigs express m1AChRs. In contrast, in rats only ∼25% of the PV population is immunoreactive for m1AChRs. Our data reveal that while they do so much less frequently than in primates, PV neurons in rats do express Gq-coupled muscarinic AChRs, which appear to have gone undetected in the previous in vitro studies. Data such as these are critical in determining the species that represent adequate models for the capacity of the cholinergic system to modulate inhibition in the primate cortex. Copyright © 2013 Wiley Periodicals, Inc.

Unravelling the development of the visual cortex: implications for plasticity and repair

PubMed Central

Bourne, James A

2010-01-01

The visual cortex comprises over 50 areas in the human, each with a specified role and distinct physiology, connectivity and cellular morphology. How these individual areas emerge during development still remains something of a mystery and, although much attention has been paid to the initial stages of the development of the visual cortex, especially its lamination, very little is known about the mechanisms responsible for the arealization and functional organization of this region of the brain. In recent years we have started to discover that it is the interplay of intrinsic (molecular) and extrinsic (afferent connections) cues that are responsible for the maturation of individual areas, and that there is a spatiotemporal sequence in the maturation of the primary visual cortex (striate cortex, V1) and the multiple extrastriate/association areas. Studies in both humans and non-human primates have started to highlight the specific neural underpinnings responsible for the maturation of the visual cortex, and how experience-dependent plasticity and perturbations to the visual system can impact upon its normal development. Furthermore, damage to specific nuclei of the visual cortex, such as the primary visual cortex (V1), is a common occurrence as a result of a stroke, neurotrauma, disease or hypoxia in both neonates and adults alike. However, the consequences of a focal injury differ between the immature and adult brain, with the immature brain demonstrating a higher level of functional resilience. With better techniques for examining specific molecular and connectional changes, we are now starting to uncover the mechanisms responsible for the increased neural plasticity that leads to significant recovery following injury during this early phase of life. Further advances in our understanding of postnatal development/maturation and plasticity observed during early life could offer new strategies to improve outcomes by recapitulating aspects of the developmental program in the adult brain. PMID:20722872

Rates of Cerebral Protein Synthesis in Primary Visual Cortex during Sleep-Dependent Memory Consolidation, a Study in Human Subjects.

PubMed

Picchioni, Dante; Schmidt, Kathleen C; McWhirter, Kelly K; Loutaev, Inna; Pavletic, Adriana J; Speer, Andrew M; Zametkin, Alan J; Miao, Ning; Bishu, Shrinivas; Turetsky, Kate M; Morrow, Anne S; Nadel, Jeffrey L; Evans, Brittney C; Vesselinovitch, Diana M; Sheeler, Carrie A; Balkin, Thomas J; Smith, Carolyn B

2018-05-15

If protein synthesis during sleep is required for sleep-dependent memory consolidation, we might expect rates of cerebral protein synthesis (rCPS) to increase during sleep in the local brain circuits that support performance on a particular task following training on that task. To measure circuit-specific brain protein synthesis during a daytime nap opportunity, we used the L-[1-(11)C]leucine positron emission tomography (PET) method with simultaneous polysomnography. We trained subjects on the visual texture discrimination task (TDT). This was followed by a nap opportunity during the PET scan, and we retested them later in the day after the scan. The TDT is considered retinotopically specific, so we hypothesized that higher rCPS in primary visual cortex would be observed in the trained hemisphere compared to the untrained hemisphere in subjects who were randomized to a sleep condition. Our results indicate that the changes in rCPS in primary visual cortex depended on whether subjects were in the wakefulness or sleep condition but were independent of the side of the visual field trained. That is, only in the subjects randomized to sleep, rCPS in the right primary visual cortex was higher than the left regardless of side trained. Other brain regions examined were not so affected. In the subjects who slept, performance on the TDT improved similarly regardless of the side trained. Results indicate a regionally selective and sleep-dependent effect that occurs with improved performance on the TDT.

Visual Literacy in Primary Science: Exploring Anatomy Cross-Section Production Skills

ERIC Educational Resources Information Center

García Fernández, Beatriz; Ruiz-Gallardo, José Reyes

2017-01-01

Are children competent producing anatomy cross-sections? To answer this question, we carried out a case study research aimed at testing graphic production skills in anatomy of nutrition. The graphics produced by 118 children in the final year of primary education were analysed. The children had to draw a diagram of a human cross section,…

The influence of spontaneous activity on stimulus processing in primary visual cortex.

PubMed

Schölvinck, M L; Friston, K J; Rees, G

2012-02-01

Spontaneous activity in the resting human brain has been studied extensively; however, how such activity affects the local processing of a sensory stimulus is relatively unknown. Here, we examined the impact of spontaneous activity in primary visual cortex on neuronal and behavioural responses to a simple visual stimulus, using functional MRI. Stimulus-evoked responses remained essentially unchanged by spontaneous fluctuations, combining with them in a largely linear fashion (i.e., with little evidence for an interaction). However, interactions between spontaneous fluctuations and stimulus-evoked responses were evident behaviourally; high levels of spontaneous activity tended to be associated with increased stimulus detection at perceptual threshold. Our results extend those found in studies of spontaneous fluctuations in motor cortex and higher order visual areas, and suggest a fundamental role for spontaneous activity in stimulus processing. Copyright © 2011. Published by Elsevier Inc.

Multichannel optical mapping: investigation of depth information

NASA Astrophysics Data System (ADS)

Sase, Ichiro; Eda, Hideo; Seiyama, Akitoshi; Tanabe, Hiroki C.; Takatsuki, Akira; Yanagida, Toshio

2001-06-01

Near infrared (NIR) light has become a powerful tool for non-invasive imaging of human brain activity. Many systems have been developed to capture the changes in regional brain blood flow and hemoglobin oxygenation, which occur in the human cortex in response to neural activity. We have developed a multi-channel reflectance imaging system, which can be used as a `mapping device' and also as a `multi-channel spectrophotometer'. In the present study, we visualized changes in the hemodynamics of the human occipital region in multiple ways. (1) Stimulating left and right primary visual cortex independently by showing sector shaped checkerboards sequentially over the contralateral visual field, resulted in corresponding changes in the hemodynamics observed by `mapping' measurement. (2) Simultaneous measurement of functional-MRI and NIR (changes in total hemoglobin) during visual stimulation showed good spatial and temporal correlation with each other. (3) Placing multiple channels densely over the occipital region demonstrated spatial patterns more precisely, and depth information was also acquired by placing each pair of illumination and detection fibers at various distances. These results indicate that optical method can provide data for 3D analysis of human brain functions.

Independent effects of motivation and spatial attention in the human visual cortex.

PubMed

Bayer, Mareike; Rossi, Valentina; Vanlessen, Naomi; Grass, Annika; Schacht, Annekathrin; Pourtois, Gilles

2017-01-01

Motivation and attention constitute major determinants of human perception and action. Nonetheless, it remains a matter of debate whether motivation effects on the visual cortex depend on the spatial attention system, or rely on independent pathways. This study investigated the impact of motivation and spatial attention on the activity of the human primary and extrastriate visual cortex by employing a factorial manipulation of the two factors in a cued pattern discrimination task. During stimulus presentation, we recorded event-related potentials and pupillary responses. Motivational relevance increased the amplitudes of the C1 component at ∼70 ms after stimulus onset. This modulation occurred independently of spatial attention effects, which were evident at the P1 level. Furthermore, motivation and spatial attention had independent effects on preparatory activation as measured by the contingent negative variation; and pupil data showed increased activation in response to incentive targets. Taken together, these findings suggest independent pathways for the influence of motivation and spatial attention on the activity of the human visual cortex. © The Author (2016). Published by Oxford University Press.

Learning and Recognition of a Non-conscious Sequence of Events in Human Primary Visual Cortex.

PubMed

Rosenthal, Clive R; Andrews, Samantha K; Antoniades, Chrystalina A; Kennard, Christopher; Soto, David

2016-03-21

Human primary visual cortex (V1) has long been associated with learning simple low-level visual discriminations [1] and is classically considered outside of neural systems that support high-level cognitive behavior in contexts that differ from the original conditions of learning, such as recognition memory [2, 3]. Here, we used a novel fMRI-based dichoptic masking protocol-designed to induce activity in V1, without modulation from visual awareness-to test whether human V1 is implicated in human observers rapidly learning and then later (15-20 min) recognizing a non-conscious and complex (second-order) visuospatial sequence. Learning was associated with a change in V1 activity, as part of a temporo-occipital and basal ganglia network, which is at variance with the cortico-cerebellar network identified in prior studies of "implicit" sequence learning that involved motor responses and visible stimuli (e.g., [4]). Recognition memory was associated with V1 activity, as part of a temporo-occipital network involving the hippocampus, under conditions that were not imputable to mechanisms associated with conscious retrieval. Notably, the V1 responses during learning and recognition separately predicted non-conscious recognition memory, and functional coupling between V1 and the hippocampus was enhanced for old retrieval cues. The results provide a basis for novel hypotheses about the signals that can drive recognition memory, because these data (1) identify human V1 with a memory network that can code complex associative serial visuospatial information and support later non-conscious recognition memory-guided behavior (cf. [5]) and (2) align with mouse models of experience-dependent V1 plasticity in learning and memory [6]. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preprocessing of emotional visual information in the human piriform cortex.

PubMed

Schulze, Patrick; Bestgen, Anne-Kathrin; Lech, Robert K; Kuchinke, Lars; Suchan, Boris

2017-08-23

This study examines the processing of visual information by the olfactory system in humans. Recent data point to the processing of visual stimuli by the piriform cortex, a region mainly known as part of the primary olfactory cortex. Moreover, the piriform cortex generates predictive templates of olfactory stimuli to facilitate olfactory processing. This study fills the gap relating to the question whether this region is also capable of preprocessing emotional visual information. To gain insight into the preprocessing and transfer of emotional visual information into olfactory processing, we recorded hemodynamic responses during affective priming using functional magnetic resonance imaging (fMRI). Odors of different valence (pleasant, neutral and unpleasant) were primed by images of emotional facial expressions (happy, neutral and disgust). Our findings are the first to demonstrate that the piriform cortex preprocesses emotional visual information prior to any olfactory stimulation and that the emotional connotation of this preprocessing is subsequently transferred and integrated into an extended olfactory network for olfactory processing.

Dissociation and Convergence of the Dorsal and Ventral Visual Streams in the Human Prefrontal Cortex

PubMed Central

Takahashi, Emi; Ohki, Kenichi; Kim, Dae-Shik

2012-01-01

Visual information is largely processed through two pathways in the primate brain: an object pathway from the primary visual cortex to the temporal cortex (ventral stream) and a spatial pathway to the parietal cortex (dorsal stream). Whether and to what extent dissociation exists in the human prefrontal cortex (PFC) has long been debated. We examined anatomical connections from functionally defined areas in the temporal and parietal cortices to the PFC, using noninvasive functional and diffusion-weighted magnetic resonance imaging. The right inferior frontal gyrus (IFG) received converging input from both streams, while the right superior frontal gyrus received input only from the dorsal stream. Interstream functional connectivity to the IFG was dynamically recruited only when both object and spatial information were processed. These results suggest that the human PFC receives dissociated and converging visual pathways, and that the right IFG region serves as an integrator of the two types of information. PMID:23063444

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.

Correlation Based Target Location and Identification

DTIC Science & Technology

1992-12-01

Research Daugman (7) cites research on the mammalian visual nervous system (retina, lateral geniculate , and primary visual cortex) as motivation for...brains, they can still sort slides into natural categories such as people, trees, and bodies of water, a capability that humans do easily. As such...critical neurobiological variables of a given neuron’s orientation and spatial frequency preference, the tuning bandwidths for these variables, the

Functional size of human visual area V1: a neural correlate of top-down attention.

PubMed

Verghese, Ashika; Kolbe, Scott C; Anderson, Andrew J; Egan, Gary F; Vidyasagar, Trichur R

2014-06-01

Heavy demands are placed on the brain's attentional capacity when selecting a target item in a cluttered visual scene, or when reading. It is widely accepted that such attentional selection is mediated by top-down signals from higher cortical areas to early visual areas such as the primary visual cortex (V1). Further, it has also been reported that there is considerable variation in the surface area of V1. This variation may impact on either the number or specificity of attentional feedback signals and, thereby, the efficiency of attentional mechanisms. In this study, we investigated whether individual differences between humans performing attention-demanding tasks can be related to the functional area of V1. We found that those with a larger representation in V1 of the central 12° of the visual field as measured using BOLD signals from fMRI were able to perform a serial search task at a faster rate. In line with recent suggestions of the vital role of visuo-spatial attention in reading, the speed of reading showed a strong positive correlation with the speed of visual search, although it showed little correlation with the size of V1. The results support the idea that the functional size of the primary visual cortex is an important determinant of the efficiency of selective spatial attention for simple tasks, and that the attentional processing required for complex tasks like reading are to a large extent determined by other brain areas and inter-areal connections. Copyright © 2014 Elsevier Inc. All rights reserved.

Automatic analysis of the micronucleus test in primary human lymphocytes using image analysis.

PubMed

Frieauff, W; Martus, H J; Suter, W; Elhajouji, A

2013-01-01

The in vitro micronucleus test (MNT) is a well-established test for early screening of new chemical entities in industrial toxicology. For assessing the clastogenic or aneugenic potential of a test compound, micronucleus induction in cells has been shown repeatedly to be a sensitive and a specific parameter. Various automated systems to replace the tedious and time-consuming visual slide analysis procedure as well as flow cytometric approaches have been discussed. The ROBIAS (Robotic Image Analysis System) for both automatic cytotoxicity assessment and micronucleus detection in human lymphocytes was developed at Novartis where the assay has been used to validate positive results obtained in the MNT in TK6 cells, which serves as the primary screening system for genotoxicity profiling in early drug development. In addition, the in vitro MNT has become an accepted alternative to support clinical studies and will be used for regulatory purposes as well. The comparison of visual with automatic analysis results showed a high degree of concordance for 25 independent experiments conducted for the profiling of 12 compounds. For concentration series of cyclophosphamide and carbendazim, a very good correlation between automatic and visual analysis by two examiners could be established, both for the relative division index used as cytotoxicity parameter, as well as for micronuclei scoring in mono- and binucleated cells. Generally, false-positive micronucleus decisions could be controlled by fast and simple relocation of the automatically detected patterns. The possibility to analyse 24 slides within 65h by automatic analysis over the weekend and the high reproducibility of the results make automatic image processing a powerful tool for the micronucleus analysis in primary human lymphocytes. The automated slide analysis for the MNT in human lymphocytes complements the portfolio of image analysis applications on ROBIAS which is supporting various assays at Novartis.

Repetitive Transcranial Magnetic Stimulation to the Primary Motor Cortex Interferes with Motor Learning by Observing

ERIC Educational Resources Information Center

Brown, Liana E.; Wilson, Elizabeth T.; Gribble, Paul L.

2009-01-01

Neural representations of novel motor skills can be acquired through visual observation. We used repetitive transcranial magnetic stimulation (rTMS) to test the idea that this "motor learning by observing" is based on engagement of neural processes for learning in the primary motor cortex (M1). Human subjects who observed another person learning…

Visual analytics as a translational cognitive science.

PubMed

Fisher, Brian; Green, Tera Marie; Arias-Hernández, Richard

2011-07-01

Visual analytics is a new interdisciplinary field of study that calls for a more structured scientific approach to understanding the effects of interaction with complex graphical displays on human cognitive processes. Its primary goal is to support the design and evaluation of graphical information systems that better support cognitive processes in areas as diverse as scientific research and emergency management. The methodologies that make up this new field are as yet ill defined. This paper proposes a pathway for development of visual analytics as a translational cognitive science that bridges fundamental research in human/computer cognitive systems and design and evaluation of information systems in situ. Achieving this goal will require the development of enhanced field methods for conceptual decomposition of human/computer cognitive systems that maps onto laboratory studies, and improved methods for conducting laboratory investigations that might better map onto real-world cognitive processes in technology-rich environments. Copyright © 2011 Cognitive Science Society, Inc.

The basis of orientation decoding in human primary visual cortex: fine- or coarse-scale biases?

PubMed

Maloney, Ryan T

2015-01-01

Orientation signals in human primary visual cortex (V1) can be reliably decoded from the multivariate pattern of activity as measured with functional magnetic resonance imaging (fMRI). The precise underlying source of these decoded signals (whether by orientation biases at a fine or coarse scale in cortex) remains a matter of some controversy, however. Freeman and colleagues (J Neurosci 33: 19695-19703, 2013) recently showed that the accuracy of decoding of spiral patterns in V1 can be predicted by a voxel's preferred spatial position (the population receptive field) and its coarse orientation preference, suggesting that coarse-scale biases are sufficient for orientation decoding. Whether they are also necessary for decoding remains an open question, and one with implications for the broader interpretation of multivariate decoding results in fMRI studies. Copyright © 2015 the American Physiological Society.

Distribution of Vesicular Glutamate Transporter 2 (VGluT2) in the Primary Visual Cortex of the Macaque and Human

PubMed Central

Garcia-Marin, Virginia; Ahmed, Tunazzina H.; Afzal, Yasmeen C.; Hawken, Michael J.

2014-01-01

The majority of thalamic terminals in V1 arise from lateral geniculate nucleus (LGN) afferents. Thalamic afferent terminals are preferentially labeled by an isoform of the vesicular glutamate transporter, VGluT2. The goal of our study was to determine the distribution of VGluT2-ir puncta in macaque and human visual cortex. First, we investigated the distribution of VGluT2-ir puncta in all layers of macaque monkey primary visual cortex (V1), and found a very close correspondence between the known distribution of LGN afferents from previous studies and the distribution of VGluT2-immunoreactive (-ir) puncta. There was also a close correspondence between cytochrome oxidase density and VGluT2-ir puncta distribution. After validating the correspondence in macaque, we made a comparative study in human V1. In many aspects, the distribution of VGluT2-ir puncta in human was qualitatively similar to that of the macaque: high densities in layer 4C, patches of VGluT2-ir puncta in the supragranular layer (2/3), lower but clear distribution in layers 1 and 6, and very few puncta in layers 5 and 4B. However, there were also important differences between macaques and humans. In layer 4A of human, there was a sparse distribution of VGluT2-ir puncta, whereas in macaque, there was a dense distribution with the characteristic honeycomb organization. The results suggest important changes in the pattern of cortical VGluT2 immunostaining that may be related to evolutionary differences in the cortical organization of LGN afferents between Old World monkeys and humans. PMID:22684983

On the Visual Input Driving Human Smooth-Pursuit Eye Movements

NASA Technical Reports Server (NTRS)

Stone, Leland S.; Beutter, Brent R.; Lorenceau, Jean

1996-01-01

Current computational models of smooth-pursuit eye movements assume that the primary visual input is local retinal-image motion (often referred to as retinal slip). However, we show that humans can pursue object motion with considerable accuracy, even in the presence of conflicting local image motion. This finding indicates that the visual cortical area(s) controlling pursuit must be able to perform a spatio-temporal integration of local image motion into a signal related to object motion. We also provide evidence that the object-motion signal that drives pursuit is related to the signal that supports perception. We conclude that current models of pursuit should be modified to include a visual input that encodes perceived object motion and not merely retinal image motion. Finally, our findings suggest that the measurement of eye movements can be used to monitor visual perception, with particular value in applied settings as this non-intrusive approach would not require interrupting ongoing work or training.

Resolving human object recognition in space and time

PubMed Central

Cichy, Radoslaw Martin; Pantazis, Dimitrios; Oliva, Aude

2014-01-01

A comprehensive picture of object processing in the human brain requires combining both spatial and temporal information about brain activity. Here, we acquired human magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) responses to 92 object images. Multivariate pattern classification applied to MEG revealed the time course of object processing: whereas individual images were discriminated by visual representations early, ordinate and superordinate category levels emerged relatively later. Using representational similarity analysis, we combine human fMRI and MEG to show content-specific correspondence between early MEG responses and primary visual cortex (V1), and later MEG responses and inferior temporal (IT) cortex. We identified transient and persistent neural activities during object processing, with sources in V1 and IT., Finally, human MEG signals were correlated to single-unit responses in monkey IT. Together, our findings provide an integrated space- and time-resolved view of human object categorization during the first few hundred milliseconds of vision. PMID:24464044

Tracking blue cone signals in the primate brain.

PubMed

Jayakumar, Jaikishan; Dreher, Bogdan; Vidyasagar, Trichur R

2013-05-01

In this paper, we review the path taken by signals originating from the short wavelength sensitive cones (S-cones) in Old World and New World primates. Two types of retinal ganglion cells (RGCs) carrying S-cone signals (blue-On and blue-Off cells) project to the dorsal lateral geniculate nucleus (dLGN) in the thalamus. In all primates, these S-cone signals are relayed through the 'dust-like' (konis in classical Greek) dLGN cells. In New World primates such as common marmoset, these very small cells are known to form distinct and spatially extensive, koniocellular layers. Although in Old World primates, such as macaques, koniocellular layers tend to be very thin, the adjacent parvocellular layers contain distinct koniocellular extensions. It appears that all S-cone signals are relayed through such konio cells, whether they are in the main koniocellular layers or in their colonies within the parvocellular layers of the dLGN. In the primary visual cortex, these signals begin to merge with the signals carried by the other two principal parallel channels, namely the magnocellular and parvocellular channels. This article will also review the possible routes taken by the S-cone signals to reach one of the topographically organised extrastriate visual cortical areas, the middle temporal area (area MT). This area is the major conduit for signals reaching the parietal cortex. Alternative visual inputs to area MT not relayed via the primary visual cortex area (V1) may provide the neurological basis for the phenomenon of 'blindsight' observed in human and non-human primates, who have partial or complete damage to the primary visual cortex. Short wavelength sensitive cone (S-cone) signals to area MT may also play a role in directing visual attention with possible implications for understanding the pathology in dyslexia and some of its treatment options. © 2012 The Authors. Clinical and Experimental Optometry © 2012 Optometrists Association Australia.

From the optic tectum to the primary visual cortex: migration through evolution of the saliency map for exogenous attentional guidance.

PubMed

Zhaoping, Li

2016-10-01

Recent data have supported the hypothesis that, in primates, the primary visual cortex (V1) creates a saliency map from visual input. The exogenous guidance of attention is then realized by means of monosynaptic projections to the superior colliculus, which can select the most salient location as the target of a gaze shift. V1 is less prominent, or is even absent in lower vertebrates such as fish; whereas the superior colliculus, called optic tectum in lower vertebrates, also receives retinal input. I review the literature and propose that the saliency map has migrated from the tectum to V1 over evolution. In addition, attentional benefits manifested as cueing effects in humans should also be present in lower vertebrates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of Object Recognition Behavior in Human and Monkey

PubMed Central

Rajalingham, Rishi; Schmidt, Kailyn

2015-01-01

Although the rhesus monkey is used widely as an animal model of human visual processing, it is not known whether invariant visual object recognition behavior is quantitatively comparable across monkeys and humans. To address this question, we systematically compared the core object recognition behavior of two monkeys with that of human subjects. To test true object recognition behavior (rather than image matching), we generated several thousand naturalistic synthetic images of 24 basic-level objects with high variation in viewing parameters and image background. Monkeys were trained to perform binary object recognition tasks on a match-to-sample paradigm. Data from 605 human subjects performing the same tasks on Mechanical Turk were aggregated to characterize “pooled human” object recognition behavior, as well as 33 separate Mechanical Turk subjects to characterize individual human subject behavior. Our results show that monkeys learn each new object in a few days, after which they not only match mean human performance but show a pattern of object confusion that is highly correlated with pooled human confusion patterns and is statistically indistinguishable from individual human subjects. Importantly, this shared human and monkey pattern of 3D object confusion is not shared with low-level visual representations (pixels, V1+; models of the retina and primary visual cortex) but is shared with a state-of-the-art computer vision feature representation. Together, these results are consistent with the hypothesis that rhesus monkeys and humans share a common neural shape representation that directly supports object perception. SIGNIFICANCE STATEMENT To date, several mammalian species have shown promise as animal models for studying the neural mechanisms underlying high-level visual processing in humans. In light of this diversity, making tight comparisons between nonhuman and human primates is particularly critical in determining the best use of nonhuman primates to further the goal of the field of translating knowledge gained from animal models to humans. To the best of our knowledge, this study is the first systematic attempt at comparing a high-level visual behavior of humans and macaque monkeys. PMID:26338324

Integration of Visual and Proprioceptive Limb Position Information in Human Posterior Parietal, Premotor, and Extrastriate Cortex.

PubMed

Limanowski, Jakub; Blankenburg, Felix

2016-03-02

The brain constructs a flexible representation of the body from multisensory information. Previous work on monkeys suggests that the posterior parietal cortex (PPC) and ventral premotor cortex (PMv) represent the position of the upper limbs based on visual and proprioceptive information. Human experiments on the rubber hand illusion implicate similar regions, but since such experiments rely on additional visuo-tactile interactions, they cannot isolate visuo-proprioceptive integration. Here, we independently manipulated the position (palm or back facing) of passive human participants' unseen arm and of a photorealistic virtual 3D arm. Functional magnetic resonance imaging (fMRI) revealed that matching visual and proprioceptive information about arm position engaged the PPC, PMv, and the body-selective extrastriate body area (EBA); activity in the PMv moreover reflected interindividual differences in congruent arm ownership. Further, the PPC, PMv, and EBA increased their coupling with the primary visual cortex during congruent visuo-proprioceptive position information. These results suggest that human PPC, PMv, and EBA evaluate visual and proprioceptive position information and, under sufficient cross-modal congruence, integrate it into a multisensory representation of the upper limb in space. The position of our limbs in space constantly changes, yet the brain manages to represent limb position accurately by combining information from vision and proprioception. Electrophysiological recordings in monkeys have revealed neurons in the posterior parietal and premotor cortices that seem to implement and update such a multisensory limb representation, but this has been difficult to demonstrate in humans. Our fMRI experiment shows that human posterior parietal, premotor, and body-selective visual brain areas respond preferentially to a virtual arm seen in a position corresponding to one's unseen hidden arm, while increasing their communication with regions conveying visual information. These brain areas thus likely integrate visual and proprioceptive information into a flexible multisensory body representation. Copyright © 2016 the authors 0270-6474/16/362582-08$15.00/0.

Characterizing synaptic protein development in human visual cortex enables alignment of synaptic age with rat visual cortex

PubMed Central

Pinto, Joshua G. A.; Jones, David G.; Williams, C. Kate; Murphy, Kathryn M.

2015-01-01

Although many potential neuroplasticity based therapies have been developed in the lab, few have translated into established clinical treatments for human neurologic or neuropsychiatric diseases. Animal models, especially of the visual system, have shaped our understanding of neuroplasticity by characterizing the mechanisms that promote neural changes and defining timing of the sensitive period. The lack of knowledge about development of synaptic plasticity mechanisms in human cortex, and about alignment of synaptic age between animals and humans, has limited translation of neuroplasticity therapies. In this study, we quantified expression of a set of highly conserved pre- and post-synaptic proteins (Synapsin, Synaptophysin, PSD-95, Gephyrin) and found that synaptic development in human primary visual cortex (V1) continues into late childhood. Indeed, this is many years longer than suggested by neuroanatomical studies and points to a prolonged sensitive period for plasticity in human sensory cortex. In addition, during childhood we found waves of inter-individual variability that are different for the four proteins and include a stage during early development (<1 year) when only Gephyrin has high inter-individual variability. We also found that pre- and post-synaptic protein balances develop quickly, suggesting that maturation of certain synaptic functions happens within the 1 year or 2 of life. A multidimensional analysis (principle component analysis) showed that most of the variance was captured by the sum of the four synaptic proteins. We used that sum to compare development of human and rat visual cortex and identified a simple linear equation that provides robust alignment of synaptic age between humans and rats. Alignment of synaptic ages is important for age-appropriate targeting and effective translation of neuroplasticity therapies from the lab to the clinic. PMID:25729353

Functional localization of the human color center by decreased water displacement using diffusion-weighted fMRI.

PubMed

Williams, Rebecca J; Reutens, David C; Hocking, Julia

2015-11-01

Decreased water displacement following increased neural activity has been observed using diffusion-weighted functional MRI (DfMRI) at high b-values. The physiological mechanisms underlying the diffusion signal change may be unique from the standard blood oxygenation level-dependent (BOLD) contrast and closer to the source of neural activity. Whether DfMRI reflects neural activity more directly than BOLD outside the primary cerebral regions remains unclear. Colored and achromatic Mondrian visual stimuli were statistically contrasted to functionally localize the human color center Area V4 in neurologically intact adults. Spatial and temporal properties of DfMRI and BOLD activation were examined across regions of the visual cortex. At the individual level, DfMRI activation patterns showed greater spatial specificity to V4 than BOLD. The BOLD activation patterns were more prominent in the primary visual cortex than DfMRI, where activation was localized to the ventral temporal lobe. Temporally, the diffusion signal change in V4 and V1 both preceded the corresponding hemodynamic response, however the early diffusion signal change was more evident in V1. DfMRI may be of use in imaging applications implementing cognitive subtraction paradigms, and where highly precise individual functional localization is required.

SDBI 1904: Human Factors Assessment of Vibration Effects on Visual Performance during Launch

NASA Technical Reports Server (NTRS)

Thompson, Shelby G.; Holden, Kritina; Root, Phillip; Ebert, Douglas; Jones, Jeffery; Adelstein, Bernard

2009-01-01

The primary objective of the of Human Factors Short Duration Bioastronautics Investigation (SDBI) 1904 is to determine visual performance limits during operational vibration and g-loads, specifically through the determination of minimal usable font sized using Orion-type display formats. Currently there is little to no data available to quantify human visual performance under these extreme conditions. Existing data on shuttle vibration magnitude and frequency is incomplete, does not address sear and crew vibration in the current configuration, and does not address human visual performance. There have been anecdotal reports of performance decrements from shuttle crews, but no structured data has been collected. The SDBI is a companion effort to the Detailed Test Objective (DTO) 695, which will measure shuttle seat accelerations (vibration) during ascent. Data fro the SDBI will serve an important role in interpreting the DTO vibration data. This data will be collected during the ascent phase of three shuttle missions (STS-119, 127, and 128). Both SDBI1904 and DTO 695 are low impact with respect to flight resources, and combined they represent an efficient and focused problem solving approach. The SDBI and DTO data will be correlated to determine the nature of perceived visual performance under varying vibrations and g-loads. This project will provide: 1) Immediate data for developing preliminary human performance vibration requirements; 2) Flight validated inputs for ongoing and future ground-based research; and 3) Information of functional needs that will drive Orion display format design decisions.

HUMAN ELECTRORETINOGRAPHY AS A GAUGE OF VISUAL PERFORMANCE.

DTIC Science & Technology

arthritis, congenital aphakia, high myopia, primary and secondary retinitis pigmentosa , optic atrophy, glaucoma, trauma, cataract and neonates. A chart of...A short review of the clinical findings with the Cordis ERG apparatus to date is presented on: night-blindness, retinal detachment, rheumatoid

Learning of goal-relevant and -irrelevant complex visual sequences in human V1.

PubMed

Rosenthal, Clive R; Mallik, Indira; Caballero-Gaudes, Cesar; Sereno, Martin I; Soto, David

2018-06-12

Learning and memory are supported by a network involving the medial temporal lobe and linked neocortical regions. Emerging evidence indicates that primary visual cortex (i.e., V1) may contribute to recognition memory, but this has been tested only with a single visuospatial sequence as the target memorandum. The present study used functional magnetic resonance imaging to investigate whether human V1 can support the learning of multiple, concurrent complex visual sequences involving discontinous (second-order) associations. Two peripheral, goal-irrelevant but structured sequences of orientated gratings appeared simultaneously in fixed locations of the right and left visual fields alongside a central, goal-relevant sequence that was in the focus of spatial attention. Pseudorandom sequences were introduced at multiple intervals during the presentation of the three structured visual sequences to provide an online measure of sequence-specific knowledge at each retinotopic location. We found that a network involving the precuneus and V1 was involved in learning the structured sequence presented at central fixation, whereas right V1 was modulated by repeated exposure to the concurrent structured sequence presented in the left visual field. The same result was not found in left V1. These results indicate for the first time that human V1 can support the learning of multiple concurrent sequences involving complex discontinuous inter-item associations, even peripheral sequences that are goal-irrelevant. Copyright © 2018. Published by Elsevier Inc.

Perceptual Learning Selectively Refines Orientation Representations in Early Visual Cortex

PubMed Central

Jehee, Janneke F.M.; Ling, Sam; Swisher, Jascha D.; van Bergen, Ruben S.; Tong, Frank

2013-01-01

Although practice has long been known to improve perceptual performance, the neural basis of this improvement in humans remains unclear. Using fMRI in conjunction with a novel signal detection-based analysis, we show that extensive practice selectively enhances the neural representation of trained orientations in the human visual cortex. Twelve observers practiced discriminating small changes in the orientation of a laterally presented grating over 20 or more daily one-hour training sessions. Training on average led to a two-fold improvement in discrimination sensitivity, specific to the trained orientation and the trained location, with minimal improvement found for untrained orthogonal orientations or for orientations presented in the untrained hemifield. We measured the strength of orientation-selective responses in individual voxels in early visual areas (V1–V4) using signal detection measures, both pre- and post-training. Although the overall amplitude of the BOLD response was no greater after training, practice nonetheless specifically enhanced the neural representation of the trained orientation at the trained location. This training-specific enhancement of orientation-selective responses was observed in the primary visual cortex (V1) as well as higher extrastriate visual areas V2–V4, and moreover, reliably predicted individual differences in the behavioral effects of perceptual learning. These results demonstrate that extensive training can lead to targeted functional reorganization of the human visual cortex, refining the cortical representation of behaviorally relevant information. PMID:23175828

Perceptual learning selectively refines orientation representations in early visual cortex.

PubMed

Jehee, Janneke F M; Ling, Sam; Swisher, Jascha D; van Bergen, Ruben S; Tong, Frank

2012-11-21

Although practice has long been known to improve perceptual performance, the neural basis of this improvement in humans remains unclear. Using fMRI in conjunction with a novel signal detection-based analysis, we show that extensive practice selectively enhances the neural representation of trained orientations in the human visual cortex. Twelve observers practiced discriminating small changes in the orientation of a laterally presented grating over 20 or more daily 1 h training sessions. Training on average led to a twofold improvement in discrimination sensitivity, specific to the trained orientation and the trained location, with minimal improvement found for untrained orthogonal orientations or for orientations presented in the untrained hemifield. We measured the strength of orientation-selective responses in individual voxels in early visual areas (V1-V4) using signal detection measures, both before and after training. Although the overall amplitude of the BOLD response was no greater after training, practice nonetheless specifically enhanced the neural representation of the trained orientation at the trained location. This training-specific enhancement of orientation-selective responses was observed in the primary visual cortex (V1) as well as higher extrastriate visual areas V2-V4, and moreover, reliably predicted individual differences in the behavioral effects of perceptual learning. These results demonstrate that extensive training can lead to targeted functional reorganization of the human visual cortex, refining the cortical representation of behaviorally relevant information.

Human factors evaluation of the effectiveness of multi-modality displays in advanced traveler information systems

DOT National Transportation Integrated Search

1999-12-01

To achieve the goals for Advanced Traveler Information Systems (ATIS), significant information will necessarily be provided to the driver. A primary ATIS design issue is the display modality (i.e., visual, auditory, or the combination) selected for p...

Visual assessment of the radiation distribution in the ISS Lab module: visualization in the human body

NASA Technical Reports Server (NTRS)

Saganti, P. B.; Zapp, E. N.; Wilson, J. W.; Cucinotta, F. A.

2001-01-01

The US Lab module of the International Space Station (ISS) is a primary working area where the crewmembers are expected to spend majority of their time. Because of the directionality of radiation fields caused by the Earth shadow, trapped radiation pitch angle distribution, and inherent variations in the ISS shielding, a model is needed to account for these local variations in the radiation distribution. We present the calculated radiation dose (rem/yr) values for over 3,000 different points in the working area of the Lab module and estimated radiation dose values for over 25,000 different points in the human body for a given ambient radiation environment. These estimated radiation dose values are presented in a three dimensional animated interactive visualization format. Such interactive animated visualization of the radiation distribution can be generated in near real-time to track changes in the radiation environment during the orbit precession of the ISS.

Can you hear me yet? An intracranial investigation of speech and non-speech audiovisual interactions in human cortex.

PubMed

Rhone, Ariane E; Nourski, Kirill V; Oya, Hiroyuki; Kawasaki, Hiroto; Howard, Matthew A; McMurray, Bob

In everyday conversation, viewing a talker's face can provide information about the timing and content of an upcoming speech signal, resulting in improved intelligibility. Using electrocorticography, we tested whether human auditory cortex in Heschl's gyrus (HG) and on superior temporal gyrus (STG) and motor cortex on precentral gyrus (PreC) were responsive to visual/gestural information prior to the onset of sound and whether early stages of auditory processing were sensitive to the visual content (speech syllable versus non-speech motion). Event-related band power (ERBP) in the high gamma band was content-specific prior to acoustic onset on STG and PreC, and ERBP in the beta band differed in all three areas. Following sound onset, we found with no evidence for content-specificity in HG, evidence for visual specificity in PreC, and specificity for both modalities in STG. These results support models of audio-visual processing in which sensory information is integrated in non-primary cortical areas.

Neocortical Rebound Depolarization Enhances Visual Perception

PubMed Central

Funayama, Kenta; Ban, Hiroshi; Chan, Allen W.; Matsuki, Norio; Murphy, Timothy H.; Ikegaya, Yuji

2015-01-01

Animals are constantly exposed to the time-varying visual world. Because visual perception is modulated by immediately prior visual experience, visual cortical neurons may register recent visual history into a specific form of offline activity and link it to later visual input. To examine how preceding visual inputs interact with upcoming information at the single neuron level, we designed a simple stimulation protocol in which a brief, orientated flashing stimulus was subsequently coupled to visual stimuli with identical or different features. Using in vivo whole-cell patch-clamp recording and functional two-photon calcium imaging from the primary visual cortex (V1) of awake mice, we discovered that a flash of sinusoidal grating per se induces an early, transient activation as well as a long-delayed reactivation in V1 neurons. This late response, which started hundreds of milliseconds after the flash and persisted for approximately 2 s, was also observed in human V1 electroencephalogram. When another drifting grating stimulus arrived during the late response, the V1 neurons exhibited a sublinear, but apparently increased response, especially to the same grating orientation. In behavioral tests of mice and humans, the flashing stimulation enhanced the detection power of the identically orientated visual stimulation only when the second stimulation was presented during the time window of the late response. Therefore, V1 late responses likely provide a neural basis for admixing temporally separated stimuli and extracting identical features in time-varying visual environments. PMID:26274866

Advances in color science: from retina to behavior

PubMed Central

Chatterjee, Soumya; Field, Greg D.; Horwitz, Gregory D.; Johnson, Elizabeth N.; Koida, Kowa; Mancuso, Katherine

2010-01-01

Color has become a premier model system for understanding how information is processed by neural circuits, and for investigating the relationships among genes, neural circuits and perception. Both the physical stimulus for color and the perceptual output experienced as color are quite well characterized, but the neural mechanisms that underlie the transformation from stimulus to perception are incompletely understood. The past several years have seen important scientific and technical advances that are changing our understanding of these mechanisms. Here, and in the accompanying minisymposium, we review the latest findings and hypotheses regarding color computations in the retina, primary visual cortex and higher-order visual areas, focusing on non-human primates, a model of human color vision. PMID:21068298

Prospective, observational study comparing automated and visual point-of-care urinalysis in general practice

PubMed Central

van Delft, Sanne; Goedhart, Annelijn; Spigt, Mark; van Pinxteren, Bart; de Wit, Niek; Hopstaken, Rogier

2016-01-01

Objective Point-of-care testing (POCT) urinalysis might reduce errors in (subjective) reading, registration and communication of test results, and might also improve diagnostic outcome and optimise patient management. Evidence is lacking. In the present study, we have studied the analytical performance of automated urinalysis and visual urinalysis compared with a reference standard in routine general practice. Setting The study was performed in six general practitioner (GP) group practices in the Netherlands. Automated urinalysis was compared with visual urinalysis in these practices. Reference testing was performed in a primary care laboratory (Saltro, Utrecht, The Netherlands). Primary and secondary outcome measures Analytical performance of automated and visual urinalysis compared with the reference laboratory method was the primary outcome measure, analysed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and Cohen's κ coefficient for agreement. Secondary outcome measure was the user-friendliness of the POCT analyser. Results Automated urinalysis by experienced and routinely trained practice assistants in general practice performs as good as visual urinalysis for nitrite, leucocytes and erythrocytes. Agreement for nitrite is high for automated and visual urinalysis. κ's are 0.824 and 0.803 (ranked as very good and good, respectively). Agreement with the central laboratory reference standard for automated and visual urinalysis for leucocytes is rather poor (0.256 for POCT and 0.197 for visual, respectively, ranked as fair and poor). κ's for erythrocytes are higher: 0.517 (automated) and 0.416 (visual), both ranked as moderate. The Urisys 1100 analyser was easy to use and considered to be not prone to flaws. Conclusions Automated urinalysis performed as good as traditional visual urinalysis on reading of nitrite, leucocytes and erythrocytes in routine general practice. Implementation of automated urinalysis in general practice is justified as automation is expected to reduce human errors in patient identification and transcribing of results. PMID:27503860

Induced and evoked neural correlates of orientation selectivity in human visual cortex.

PubMed

Koelewijn, Loes; Dumont, Julie R; Muthukumaraswamy, Suresh D; Rich, Anina N; Singh, Krish D

2011-02-14

Orientation discrimination is much better for patterns oriented along the horizontal or vertical (cardinal) axes than for patterns oriented obliquely, but the neural basis for this is not known. Previous animal neurophysiology and human neuroimaging studies have demonstrated only a moderate bias for cardinal versus oblique orientations, with fMRI showing a larger response to cardinals in primary visual cortex (V1) and EEG demonstrating both increased magnitudes and reduced latencies of transient evoked responses. Here, using MEG, we localised and characterised induced gamma and transient evoked responses to stationary circular grating patches of three orientations (0, 45, and 90° from vertical). Surprisingly, we found that the sustained gamma response was larger for oblique, compared to cardinal, stimuli. This "inverse oblique effect" was also observed in the earliest (80 ms) evoked response, whereas later responses (120 ms) showed a trend towards the reverse, "classic", oblique response. Source localisation demonstrated that the sustained gamma and early evoked responses were localised to medial visual cortex, whilst the later evoked responses came from both this early visual area and a source in a more inferolateral extrastriate region. These results suggest that (1) the early evoked and sustained gamma responses manifest the initial tuning of V1 neurons, with the stronger response to oblique stimuli possibly reflecting increased tuning widths for these orientations, and (2) the classic behavioural oblique effect is mediated by an extrastriate cortical area and may also implicate feedback from extrastriate to primary visual cortex. Copyright © 2010 Elsevier Inc. All rights reserved.

fMRI mapping of the visual system in the mouse brain with interleaved snapshot GE-EPI.

PubMed

Niranjan, Arun; Christie, Isabel N; Solomon, Samuel G; Wells, Jack A; Lythgoe, Mark F

2016-10-01

The use of functional magnetic resonance imaging (fMRI) in mice is increasingly prevalent, providing a means to non-invasively characterise functional abnormalities associated with genetic models of human diseases. The predominant stimulus used in task-based fMRI in the mouse is electrical stimulation of the paw. Task-based fMRI in mice using visual stimuli remains underexplored, despite visual stimuli being common in human fMRI studies. In this study, we map the mouse brain visual system with BOLD measurements at 9.4T using flashing light stimuli with medetomidine anaesthesia. BOLD responses were observed in the lateral geniculate nucleus, the superior colliculus and the primary visual area of the cortex, and were modulated by the flashing frequency, diffuse vs focussed light and stimulus context. Negative BOLD responses were measured in the visual cortex at 10Hz flashing frequency; but turned positive below 5Hz. In addition, the use of interleaved snapshot GE-EPI improved fMRI image quality without diminishing the temporal contrast-noise-ratio. Taken together, this work demonstrates a novel methodological protocol in which the mouse brain visual system can be non-invasively investigated using BOLD fMRI. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Cortical thickness development of human primary visual cortex related to the age of blindness onset.

PubMed

Li, Qiaojun; Song, Ming; Xu, Jiayuan; Qin, Wen; Yu, Chunshui; Jiang, Tianzi

2017-08-01

Blindness primarily induces structural alteration in the primary visual cortex (V1). Some studies have found that the early blind subjects had a thicker V1 compared to sighted controls, whereas late blind subjects showed no significant differences in the V1. This implies that the age of blindness onset may exert significant effects on the development of cortical thickness of the V1. However, no previous research used a trajectory of the age of blindness onset-related changes to investigate these effects. Here we explored this issue by mapping the cortical thickness trajectory of the V1 against the age of blindness onset using data from 99 blind individuals whose age of blindness onset ranged from birth to 34 years. We found that the cortical thickness of the V1 could be fitted well with a quadratic curve in both the left (F = 11.59, P = 3 × 10 -5 ) and right hemispheres (F = 6.54, P = 2 × 10 -3 ). Specifically, the cortical thickness of the V1 thinned rapidly during childhood and adolescence and did not change significantly thereafter. This trend was not observed in the primary auditory cortex (A1), primary motor cortex (M1), or primary somatosensory cortex (S1). These results provide evidence that an onset of blindness before adulthood significantly affects the cortical thickness of the V1 and suggest a critical period for cortical development of the human V1.

Primary and multisensory cortical activity is correlated with audiovisual percepts.

PubMed

Benoit, Margo McKenna; Raij, Tommi; Lin, Fa-Hsuan; Jääskeläinen, Iiro P; Stufflebeam, Steven

2010-04-01

Incongruent auditory and visual stimuli can elicit audiovisual illusions such as the McGurk effect where visual /ka/ and auditory /pa/ fuse into another percept such as/ta/. In the present study, human brain activity was measured with adaptation functional magnetic resonance imaging to investigate which brain areas support such audiovisual illusions. Subjects viewed trains of four movies beginning with three congruent /pa/ stimuli to induce adaptation. The fourth stimulus could be (i) another congruent /pa/, (ii) a congruent /ka/, (iii) an incongruent stimulus that evokes the McGurk effect in susceptible individuals (lips /ka/ voice /pa/), or (iv) the converse combination that does not cause the McGurk effect (lips /pa/ voice/ ka/). This paradigm was predicted to show increased release from adaptation (i.e. stronger brain activation) when the fourth movie and the related percept was increasingly different from the three previous movies. A stimulus change in either the auditory or the visual stimulus from /pa/ to /ka/ (iii, iv) produced within-modality and cross-modal responses in primary auditory and visual areas. A greater release from adaptation was observed for incongruent non-McGurk (iv) compared to incongruent McGurk (iii) trials. A network including the primary auditory and visual cortices, nonprimary auditory cortex, and several multisensory areas (superior temporal sulcus, intraparietal sulcus, insula, and pre-central cortex) showed a correlation between perceiving the McGurk effect and the fMRI signal, suggesting that these areas support the audiovisual illusion. Copyright 2009 Wiley-Liss, Inc.

Primary and Multisensory Cortical Activity is Correlated with Audiovisual Percepts

PubMed Central

Benoit, Margo McKenna; Raij, Tommi; Lin, Fa-Hsuan; Jääskeläinen, Iiro P.; Stufflebeam, Steven

2012-01-01

Incongruent auditory and visual stimuli can elicit audiovisual illusions such as the McGurk effect where visual /ka/ and auditory /pa/ fuse into another percept such as/ta/. In the present study, human brain activity was measured with adaptation functional magnetic resonance imaging to investigate which brain areas support such audiovisual illusions. Subjects viewed trains of four movies beginning with three congruent /pa/ stimuli to induce adaptation. The fourth stimulus could be (i) another congruent /pa/, (ii) a congruent /ka/, (iii) an incongruent stimulus that evokes the McGurk effect in susceptible individuals (lips /ka/ voice /pa/), or (iv) the converse combination that does not cause the McGurk effect (lips /pa/ voice/ ka/). This paradigm was predicted to show increased release from adaptation (i.e. stronger brain activation) when the fourth movie and the related percept was increasingly different from the three previous movies. A stimulus change in either the auditory or the visual stimulus from /pa/ to /ka/ (iii, iv) produced within-modality and cross-modal responses in primary auditory and visual areas. A greater release from adaptation was observed for incongruent non-McGurk (iv) compared to incongruent McGurk (iii) trials. A network including the primary auditory and visual cortices, nonprimary auditory cortex, and several multisensory areas (superior temporal sulcus, intraparietal sulcus, insula, and pre-central cortex) showed a correlation between perceiving the McGurk effect and the fMRI signal, suggesting that these areas support the audiovisual illusion. PMID:19780040

Cortical visual prostheses: from microstimulation to functional percept

NASA Astrophysics Data System (ADS)

Najarpour Foroushani, Armin; Pack, Christopher C.; Sawan, Mohamad

2018-04-01

Cortical visual prostheses are intended to restore vision by targeted electrical stimulation of the visual cortex. The perception of spots of light, called phosphenes, resulting from microstimulation of the visual pathway, suggests the possibility of creating meaningful percept made of phosphenes. However, to date electrical stimulation of V1 has still not resulted in perception of phosphenated images that goes beyond punctate spots of light. In this review, we summarize the clinical and experimental progress that has been made in generating phosphenes and modulating their associated perceptual characteristics in human and macaque primary visual cortex (V1). We focus specifically on the effects of different microstimulation parameters on perception and we analyse key challenges facing the generation of meaningful artificial percepts. Finally, we propose solutions to these challenges based on the application of supervised learning of population codes for spatial stimulation of visual cortex.

Temporal information entropy of the Blood-Oxygenation Level-Dependent signals increases in the activated human primary visual cortex

NASA Astrophysics Data System (ADS)

DiNuzzo, Mauro; Mascali, Daniele; Moraschi, Marta; Bussu, Giorgia; Maraviglia, Bruno; Mangia, Silvia; Giove, Federico

2017-02-01

Time-domain analysis of blood-oxygenation level-dependent (BOLD) signals allows the identification of clusters of voxels responding to photic stimulation in primary visual cortex (V1). However, the characterization of information encoding into temporal properties of the BOLD signals of an activated cluster is poorly investigated. Here, we used Shannon entropy to determine spatial and temporal information encoding in the BOLD signal within the most strongly activated area of the human visual cortex during a hemifield photic stimulation. We determined the distribution profile of BOLD signals during epochs at rest and under stimulation within small (19-121 voxels) clusters designed to include only voxels driven by the stimulus as highly and uniformly as possible. We found consistent and significant increases (2-4% on average) in temporal information entropy during activation in contralateral but not ipsilateral V1, which was mirrored by an expected loss of spatial information entropy. These opposite changes coexisted with increases in both spatial and temporal mutual information (i.e. dependence) in contralateral V1. Thus, we showed that the first cortical stage of visual processing is characterized by a specific spatiotemporal rearrangement of intracluster BOLD responses. Our results indicate that while in the space domain BOLD maps may be incapable of capturing the functional specialization of small neuronal populations due to relatively low spatial resolution, some information encoding may still be revealed in the temporal domain by an increase of temporal information entropy.

An asymmetrical relationship between verbal and visual thinking: converging evidence from behavior and fMRI

PubMed Central

Amit, Elinor; Hoeflin, Caitlyn; Hamzah, Nada; Fedorenko, Evelina

2017-01-01

Humans rely on at least two modes of thought: verbal (inner speech) and visual (imagery). Are these modes independent, or does engaging in one entail engaging in the other? To address this question, we performed a behavioral and an fMRI study. In the behavioral experiment, participants received a prompt and were asked to either silently generate a sentence or create a visual image in their mind. They were then asked to judge the vividness of the resulting representation, and of the potentially accompanying representation in the other format. In the fMRI experiment, participants had to recall sentences or images (that they were familiarized with prior to the scanning session) given prompts, or read sentences and view images, in the control, perceptual, condition. An asymmetry was observed between inner speech and visual imagery. In particular, inner speech was engaged to a greater extent during verbal than visual thought, but visual imagery was engaged to a similar extent during both modes of thought. Thus, it appears that people generate more robust verbal representations during deliberate inner speech compared to when their intent is to visualize. However, they generate visual images regardless of whether their intent is to visualize or to think verbally. One possible interpretation of these results is that visual thinking is somehow primary, given the relatively late emergence of verbal abilities during human development and in the evolution of our species. PMID:28323162

An asymmetrical relationship between verbal and visual thinking: Converging evidence from behavior and fMRI.

PubMed

Amit, Elinor; Hoeflin, Caitlyn; Hamzah, Nada; Fedorenko, Evelina

2017-05-15

Humans rely on at least two modes of thought: verbal (inner speech) and visual (imagery). Are these modes independent, or does engaging in one entail engaging in the other? To address this question, we performed a behavioral and an fMRI study. In the behavioral experiment, participants received a prompt and were asked to either silently generate a sentence or create a visual image in their mind. They were then asked to judge the vividness of the resulting representation, and of the potentially accompanying representation in the other format. In the fMRI experiment, participants had to recall sentences or images (that they were familiarized with prior to the scanning session) given prompts, or read sentences and view images, in the control, perceptual, condition. An asymmetry was observed between inner speech and visual imagery. In particular, inner speech was engaged to a greater extent during verbal than visual thought, but visual imagery was engaged to a similar extent during both modes of thought. Thus, it appears that people generate more robust verbal representations during deliberate inner speech compared to when their intent is to visualize. However, they generate visual images regardless of whether their intent is to visualize or to think verbally. One possible interpretation of these results is that visual thinking is somehow primary, given the relatively late emergence of verbal abilities during human development and in the evolution of our species. Copyright © 2017 Elsevier Inc. All rights reserved.

Lateralization of the human mirror neuron system.

PubMed

Aziz-Zadeh, Lisa; Koski, Lisa; Zaidel, Eran; Mazziotta, John; Iacoboni, Marco

2006-03-15

A cortical network consisting of the inferior frontal, rostral inferior parietal, and posterior superior temporal cortices has been implicated in representing actions in the primate brain and is critical to imitation in humans. This neural circuitry may be an evolutionary precursor of neural systems associated with language. However, language is predominantly lateralized to the left hemisphere, whereas the degree of lateralization of the imitation circuitry in humans is unclear. We conducted a functional magnetic resonance imaging study of imitation of finger movements with lateralized stimuli and responses. During imitation, activity in the inferior frontal and rostral inferior parietal cortex, although fairly bilateral, was stronger in the hemisphere ipsilateral to the visual stimulus and response hand. This ipsilateral pattern is at variance with the typical contralateral activity of primary visual and motor areas. Reliably increased signal in the right superior temporal sulcus (STS) was observed for both left-sided and right-sided imitation tasks, although subthreshold activity was also observed in the left STS. Overall, the data indicate that visual and motor components of the human mirror system are not left-lateralized. The left hemisphere superiority for language, then, must be have been favored by other types of language precursors, perhaps auditory or multimodal action representations.

A unified account of tilt illusions, association fields, and contour detection based on elastica.

PubMed

Keemink, Sander W; van Rossum, Mark C W

2016-09-01

As expressed in the Gestalt law of good continuation, human perception tends to associate stimuli that form smooth continuations. Contextual modulation in primary visual cortex, in the form of association fields, is believed to play an important role in this process. Yet a unified and principled account of the good continuation law on the neural level is lacking. In this study we introduce a population model of primary visual cortex. Its contextual interactions depend on the elastica curvature energy of the smoothest contour connecting oriented bars. As expected, this model leads to association fields consistent with data. However, in addition the model displays tilt-illusions for stimulus configurations with grating and single bars that closely match psychophysics. Furthermore, the model explains not only pop-out of contours amid a variety of backgrounds, but also pop-out of single targets amid a uniform background. We thus propose that elastica is a unifying principle of the visual cortical network. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Multiscale neural connectivity during human sensory processing in the brain

NASA Astrophysics Data System (ADS)

Maksimenko, Vladimir A.; Runnova, Anastasia E.; Frolov, Nikita S.; Makarov, Vladimir V.; Nedaivozov, Vladimir; Koronovskii, Alexey A.; Pisarchik, Alexander; Hramov, Alexander E.

2018-05-01

Stimulus-related brain activity is considered using wavelet-based analysis of neural interactions between occipital and parietal brain areas in alpha (8-12 Hz) and beta (15-30 Hz) frequency bands. We show that human sensory processing related to the visual stimuli perception induces brain response resulted in different ways of parieto-occipital interactions in these bands. In the alpha frequency band the parieto-occipital neuronal network is characterized by homogeneous increase of the interaction between all interconnected areas both within occipital and parietal lobes and between them. In the beta frequency band the occipital lobe starts to play a leading role in the dynamics of the occipital-parietal network: The perception of visual stimuli excites the visual center in the occipital area and then, due to the increase of parieto-occipital interactions, such excitation is transferred to the parietal area, where the attentional center takes place. In the case when stimuli are characterized by a high degree of ambiguity, we find greater increase of the interaction between interconnected areas in the parietal lobe due to the increase of human attention. Based on revealed mechanisms, we describe the complex response of the parieto-occipital brain neuronal network during the perception and primary processing of the visual stimuli. The results can serve as an essential complement to the existing theory of neural aspects of visual stimuli processing.

Intrinsic, stimulus-driven and task-dependent connectivity in human auditory cortex.

PubMed

Häkkinen, Suvi; Rinne, Teemu

2018-06-01

A hierarchical and modular organization is a central hypothesis in the current primate model of auditory cortex (AC) but lacks validation in humans. Here we investigated whether fMRI connectivity at rest and during active tasks is informative of the functional organization of human AC. Identical pitch-varying sounds were presented during a visual discrimination (i.e. no directed auditory attention), pitch discrimination, and two versions of pitch n-back memory tasks. Analysis based on fMRI connectivity at rest revealed a network structure consisting of six modules in supratemporal plane (STP), temporal lobe, and inferior parietal lobule (IPL) in both hemispheres. In line with the primate model, in which higher-order regions have more longer-range connections than primary regions, areas encircling the STP module showed the highest inter-modular connectivity. Multivariate pattern analysis indicated significant connectivity differences between the visual task and rest (driven by the presentation of sounds during the visual task), between auditory and visual tasks, and between pitch discrimination and pitch n-back tasks. Further analyses showed that these differences were particularly due to connectivity modulations between the STP and IPL modules. While the results are generally in line with the primate model, they highlight the important role of human IPL during the processing of both task-irrelevant and task-relevant auditory information. Importantly, the present study shows that fMRI connectivity at rest, during presentation of sounds, and during active listening provides novel information about the functional organization of human AC.

Spatial organization of neurons in the frontal pole sets humans apart from great apes.

PubMed

Semendeferi, Katerina; Teffer, Kate; Buxhoeveden, Dan P; Park, Min S; Bludau, Sebastian; Amunts, Katrin; Travis, Katie; Buckwalter, Joseph

2011-07-01

Few morphological differences have been identified so far that distinguish the human brain from the brains of our closest relatives, the apes. Comparative analyses of the spatial organization of cortical neurons, including minicolumns, can aid our understanding of the functionally relevant aspects of microcircuitry. We measured horizontal spacing distance and gray-level ratio in layer III of 4 regions of human and ape cortex in all 6 living hominoid species: frontal pole (Brodmann area [BA] 10), and primary motor (BA 4), primary somatosensory (BA 3), and primary visual cortex (BA 17). Our results identified significant differences between humans and apes in the frontal pole (BA 10). Within the human brain, there were also significant differences between the frontal pole and 2 of the 3 regions studied (BA 3 and BA 17). Differences between BA 10 and BA 4 were present but did not reach significance. These findings in combination with earlier findings on BA 44 and BA 45 suggest that human brain evolution was likely characterized by an increase in the number and width of minicolumns and the space available for interconnectivity between neurons in the frontal lobe, especially the prefrontal cortex.

Redundancy reduction explains the expansion of visual direction space around the cardinal axes.

PubMed

Perrone, John A; Liston, Dorion B

2015-06-01

Motion direction discrimination in humans is worse for oblique directions than for the cardinal directions (the oblique effect). For some unknown reason, the human visual system makes systematic errors in the estimation of particular motion directions; a direction displacement near a cardinal axis appears larger than it really is whereas the same displacement near an oblique axis appears to be smaller. Although the perceptual effects are robust and are clearly measurable in smooth pursuit eye movements, all attempts to identify the neural underpinnings for the oblique effect have failed. Here we show that a model of image velocity estimation based on the known properties of neurons in primary visual cortex (V1) and the middle temporal (MT) visual area of the primate brain produces the oblique effect. We also provide an explanation for the unusual asymmetric patterns of inhibition that have been found surrounding MT neurons. These patterns are consistent with a mechanism within the visual system that prevents redundant velocity signals from being passed onto the next motion-integration stage, (dorsal Medial superior temporal, MSTd). We show that model redundancy-reduction mechanisms within the MT-MSTd pathway produce the oblique effect. Copyright © 2015 Elsevier Ltd. All rights reserved.

Repetitive Transcranial Direct Current Stimulation Induced Excitability Changes of Primary Visual Cortex and Visual Learning Effects-A Pilot Study.

PubMed

Sczesny-Kaiser, Matthias; Beckhaus, Katharina; Dinse, Hubert R; Schwenkreis, Peter; Tegenthoff, Martin; Höffken, Oliver

2016-01-01

Studies on noninvasive motor cortex stimulation and motor learning demonstrated cortical excitability as a marker for a learning effect. Transcranial direct current stimulation (tDCS) is a non-invasive tool to modulate cortical excitability. It is as yet unknown how tDCS-induced excitability changes and perceptual learning in visual cortex correlate. Our study aimed to examine the influence of tDCS on visual perceptual learning in healthy humans. Additionally, we measured excitability in primary visual cortex (V1). We hypothesized that anodal tDCS would improve and cathodal tDCS would have minor or no effects on visual learning. Anodal, cathodal or sham tDCS were applied over V1 in a randomized, double-blinded design over four consecutive days (n = 30). During 20 min of tDCS, subjects had to learn a visual orientation-discrimination task (ODT). Excitability parameters were measured by analyzing paired-stimulation behavior of visual-evoked potentials (ps-VEP) and by measuring phosphene thresholds (PTs) before and after the stimulation period of 4 days. Compared with sham-tDCS, anodal tDCS led to an improvement of visual discrimination learning (p < 0.003). We found reduced PTs and increased ps-VEP ratios indicating increased cortical excitability after anodal tDCS (PT: p = 0.002, ps-VEP: p = 0.003). Correlation analysis within the anodal tDCS group revealed no significant correlation between PTs and learning effect. For cathodal tDCS, no significant effects on learning or on excitability could be seen. Our results showed that anodal tDCS over V1 resulted in improved visual perceptual learning and increased cortical excitability. tDCS is a promising tool to alter V1 excitability and, hence, perceptual visual learning.

Supporting Clinical Cognition: A Human-Centered Approach to a Novel ICU Information Visualization Dashboard.

PubMed

Faiola, Anthony; Srinivas, Preethi; Duke, Jon

2015-01-01

Advances in intensive care unit bedside displays/interfaces and electronic medical record (EMR) technology have not adequately addressed the topic of visual clarity of patient data/information to further reduce cognitive load during clinical decision-making. We responded to these challenges with a human-centered approach to designing and testing a decision-support tool: MIVA 2.0 (Medical Information Visualization Assistant, v.2). Envisioned as an EMR visualization dashboard to support rapid analysis of real-time clinical data-trends, our primary goal originated from a clinical requirement to reduce cognitive overload. In the study, a convenience sample of 12 participants were recruited, in which quantitative and qualitative measures were used to compare MIVA 2.0 with ICU paper medical-charts, using time-on-task, post-test questionnaires, and interviews. Findings demonstrated a significant difference in speed and accuracy with the use of MIVA 2.0. Qualitative outcomes concurred, with participants acknowledging the potential impact of MIVA 2.0 for reducing cognitive load and enabling more accurate and quicker decision-making.

A survey of Applied Psychological Services' models of the human operator

NASA Technical Reports Server (NTRS)

Siegel, A. I.; Wolf, J. J.

1979-01-01

A historical perspective is presented in terms of the major features and status of two families of computer simulation models in which the human operator plays the primary role. Both task oriented and message oriented models are included. Two other recent efforts are summarized which deal with visual information processing. They involve not whole model development but a family of subroutines customized to add the human aspects to existing models. A global diagram of the generalized model development/validation process is presented and related to 15 criteria for model evaluation.

Attention Priority Map of Face Images in Human Early Visual Cortex.

PubMed

Mo, Ce; He, Dongjun; Fang, Fang

2018-01-03

Attention priority maps are topographic representations that are used for attention selection and guidance of task-related behavior during visual processing. Previous studies have identified attention priority maps of simple artificial stimuli in multiple cortical and subcortical areas, but investigating neural correlates of priority maps of natural stimuli is complicated by the complexity of their spatial structure and the difficulty of behaviorally characterizing their priority map. To overcome these challenges, we reconstructed the topographic representations of upright/inverted face images from fMRI BOLD signals in human early visual areas primary visual cortex (V1) and the extrastriate cortex (V2 and V3) based on a voxelwise population receptive field model. We characterized the priority map behaviorally as the first saccadic eye movement pattern when subjects performed a face-matching task relative to the condition in which subjects performed a phase-scrambled face-matching task. We found that the differential first saccadic eye movement pattern between upright/inverted and scrambled faces could be predicted from the reconstructed topographic representations in V1-V3 in humans of either sex. The coupling between the reconstructed representation and the eye movement pattern increased from V1 to V2/3 for the upright faces, whereas no such effect was found for the inverted faces. Moreover, face inversion modulated the coupling in V2/3, but not in V1. Our findings provide new evidence for priority maps of natural stimuli in early visual areas and extend traditional attention priority map theories by revealing another critical factor that affects priority maps in extrastriate cortex in addition to physical salience and task goal relevance: image configuration. SIGNIFICANCE STATEMENT Prominent theories of attention posit that attention sampling of visual information is mediated by a series of interacting topographic representations of visual space known as attention priority maps. Until now, neural evidence of attention priority maps has been limited to studies involving simple artificial stimuli and much remains unknown about the neural correlates of priority maps of natural stimuli. Here, we show that attention priority maps of face stimuli could be found in primary visual cortex (V1) and the extrastriate cortex (V2 and V3). Moreover, representations in extrastriate visual areas are strongly modulated by image configuration. These findings extend our understanding of attention priority maps significantly by showing that they are modulated, not only by physical salience and task-goal relevance, but also by the configuration of stimuli images. Copyright © 2018 the authors 0270-6474/18/380149-09$15.00/0.

Lack of Cdkl5 Disrupts the Organization of Excitatory and Inhibitory Synapses and Parvalbumin Interneurons in the Primary Visual Cortex.

PubMed

Pizzo, Riccardo; Gurgone, Antonia; Castroflorio, Enrico; Amendola, Elena; Gross, Cornelius; Sassoè-Pognetto, Marco; Giustetto, Maurizio

2016-01-01

Cyclin-dependent kinase-like 5 (CDKL5) mutations are found in severe neurodevelopmental disorders, including the Hanefeld variant of Rett syndrome (RTT; CDKL5 disorder). CDKL5 loss-of-function murine models recapitulate pathological signs of the human disease, such as visual attention deficits and reduced visual acuity. Here we investigated the cellular and synaptic substrates of visual defects by studying the organization of the primary visual cortex (V1) of Cdkl5 -/y mice. We found a severe reduction of c-Fos expression in V1 of Cdkl5 -/y mutants, suggesting circuit hypoactivity. Glutamatergic presynaptic structures were increased, but postsynaptic PSD-95 and Homer were significantly downregulated in CDKL5 mutants. Interneurons expressing parvalbumin, but not other types of interneuron, had a higher density in mutant V1, and were hyperconnected with pyramidal neurons. Finally, the developmental trajectory of pavalbumin-containing cells was also affected in Cdkl5 -/y mice, as revealed by fainter appearance perineuronal nets at the closure of the critical period (CP). The present data reveal an overall disruption of V1 cellular and synaptic organization that may cause a shift in the excitation/inhibition balance likely to underlie the visual deficits characteristic of CDKL5 disorder. Moreover, ablation of CDKL5 is likely to tamper with the mechanisms underlying experience-dependent refinement of cortical circuits during the CP of development.

Visual Literacy in Primary Science: Exploring Anatomy Cross-Section Production Skills

NASA Astrophysics Data System (ADS)

García Fernández, Beatriz; Ruiz-Gallardo, José Reyes

2017-04-01

Are children competent producing anatomy cross-sections? To answer this question, we carried out a case study research aimed at testing graphic production skills in anatomy of nutrition. The graphics produced by 118 children in the final year of primary education were analysed. The children had to draw a diagram of a human cross section, integrating knowledge of anatomy acquired from longitudinal sections. The results show that they have very limited skills in producing these graphics judging by the dimensions (scale, shape, organs represented and its organization inside the section) and their conception of human anatomy at thoracic level (location of the organs, elements in the spaces between them and connections between organs). The results also indicate that the only exposure to cross-sections in daily life is not enough by itself to draw them correctly, so this type of graphic production should be addressed from the earliest stages of education, since it contributes to the development of visual literacy, and this is a crucial skill when it comes to learning science concepts and developing scientific literacy.

Representation of the visual field in the primary visual area of the marmoset monkey: magnification factors, point-image size, and proportionality to retinal ganglion cell density.

PubMed

Chaplin, Tristan A; Yu, Hsin-Hao; Rosa, Marcello G P

2013-04-01

The primary visual area (V1) forms a systematic map of the visual field, in which adjacent cell clusters represent adjacent points of visual space. A precise quantification of this map is key to understanding the anatomical relationships between neurons located in different stations of the visual pathway, as well as the neural bases of visual performance in different regions of the visual field. We used computational methods to quantify the visual topography of V1 in the marmoset (Callithrix jacchus), a small diurnal monkey. The receptive fields of neurons throughout V1 were mapped in two anesthetized animals using electrophysiological recordings. Following histological reconstruction, precise 3D reconstructions of the V1 surface and recording sites were generated. We found that the areal magnification factor (M(A) ) decreases with eccentricity following a function that has the same slope as that observed in larger diurnal primates, including macaque, squirrel, and capuchin monkeys, and humans. However, there was no systematic relationship between M(A) and polar angle. Despite individual variation in the shape of V1, the relationship between M(A) and eccentricity was preserved across cases. Comparison between V1 and the retinal ganglion cell density demonstrated preferential magnification of central space in the cortex. The size of the cortical compartment activated by a punctiform stimulus decreased from the foveal representation towards the peripheral representation. Nonetheless, the relationship between the receptive field sizes of V1 cells and the density of ganglion cells suggested that each V1 cell receives information from a similar number of retinal neurons, throughout the visual field. Copyright © 2012 Wiley Periodicals, Inc.

Cognitive processing in the primary visual cortex: from perception to memory.

PubMed

Supèr, Hans

2002-01-01

The primary visual cortex is the first cortical area of the visual system that receives information from the external visual world. Based on the receptive field characteristics of the neurons in this area, it has been assumed that the primary visual cortex is a pure sensory area extracting basic elements of the visual scene. This information is then subsequently further processed upstream in the higher-order visual areas and provides us with perception and storage of the visual environment. However, recent findings show that such neural implementations are observed in the primary visual cortex. These neural correlates are expressed by the modulated activity of the late response of a neuron to a stimulus, and most likely depend on recurrent interactions between several areas of the visual system. This favors the concept of a distributed nature of visual processing in perceptual organization.

Functional Connectivity Between Superior Parietal Lobule and Primary Visual Cortex "at Rest" Predicts Visual Search Efficiency.

PubMed

Bueichekú, Elisenda; Ventura-Campos, Noelia; Palomar-García, María-Ángeles; Miró-Padilla, Anna; Parcet, María-Antonia; Ávila, César

2015-10-01

Spatiotemporal activity that emerges spontaneously "at rest" has been proposed to reflect individual a priori biases in cognitive processing. This research focused on testing neurocognitive models of visual attention by studying the functional connectivity (FC) of the superior parietal lobule (SPL), given its central role in establishing priority maps during visual search tasks. Twenty-three human participants completed a functional magnetic resonance imaging session that featured a resting-state scan, followed by a visual search task based on the alphanumeric category effect. As expected, the behavioral results showed longer reaction times and more errors for the within-category (i.e., searching a target letter among letters) than the between-category search (i.e., searching a target letter among numbers). The within-category condition was related to greater activation of the superior and inferior parietal lobules, occipital cortex, inferior frontal cortex, dorsal anterior cingulate cortex, and the superior colliculus than the between-category search. The resting-state FC analysis of the SPL revealed a broad network that included connections with the inferotemporal cortex, dorsolateral prefrontal cortex, and dorsal frontal areas like the supplementary motor area and frontal eye field. Noteworthy, the regression analysis revealed that the more efficient participants in the visual search showed stronger FC between the SPL and areas of primary visual cortex (V1) related to the search task. We shed some light on how the SPL establishes a priority map of the environment during visual attention tasks and how FC is a valuable tool for assessing individual differences while performing cognitive tasks.

Pupil size directly modulates the feedforward response in human primary visual cortex independently of attention.

PubMed

Bombeke, Klaas; Duthoo, Wout; Mueller, Sven C; Hopf, Jens-Max; Boehler, C Nico

2016-02-15

Controversy revolves around the question of whether psychological factors like attention and emotion can influence the initial feedforward response in primary visual cortex (V1). Although traditionally, the electrophysiological correlate of this response in humans (the C1 component) has been found to be unaltered by psychological influences, a number of recent studies have described attentional and emotional modulations. Yet, research into psychological effects on the feedforward V1 response has neglected possible direct contributions of concomitant pupil-size modulations, which are known to also occur under various conditions of attentional load and emotional state. Here we tested the hypothesis that such pupil-size differences themselves directly affect the feedforward V1 response. We report data from two complementary experiments, in which we used procedures that modulate pupil size without differences in attentional load or emotion while simultaneously recording pupil-size and EEG data. Our results confirm that pupil size indeed directly influences the feedforward V1 response, showing an inverse relationship between pupil size and early V1 activity. While it is unclear in how far this effect represents a functionally-relevant adaptation, it identifies pupil-size differences as an important modulating factor of the feedforward response of V1 and could hence represent a confounding variable in research investigating the neural influence of psychological factors on early visual processing. Copyright © 2015 Elsevier Inc. All rights reserved.

Categorisation of visualisation methods to support the design of Human-Computer Interaction Systems.

PubMed

Li, Katie; Tiwari, Ashutosh; Alcock, Jeffrey; Bermell-Garcia, Pablo

2016-07-01

During the design of Human-Computer Interaction (HCI) systems, the creation of visual artefacts forms an important part of design. On one hand producing a visual artefact has a number of advantages: it helps designers to externalise their thought and acts as a common language between different stakeholders. On the other hand, if an inappropriate visualisation method is employed it could hinder the design process. To support the design of HCI systems, this paper reviews the categorisation of visualisation methods used in HCI. A keyword search is conducted to identify a) current HCI design methods, b) approaches of selecting these methods. The resulting design methods are filtered to create a list of just visualisation methods. These are then categorised using the approaches identified in (b). As a result 23 HCI visualisation methods are identified and categorised in 5 selection approaches (The Recipient, Primary Purpose, Visual Archetype, Interaction Type, and The Design Process). Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Improving collaboration between Primary Care Research Networks using Access Grid technology.

PubMed

Nagykaldi, Zsolt; Fox, Chester; Gallo, Steve; Stone, Joseph; Fontaine, Patricia; Peterson, Kevin; Arvanitis, Theodoros

2008-01-01

Access Grid (AG) is an Internet2-driven, high performance audio-visual conferencing technology used worldwide by academic and government organisations to enhance communication, human interaction and group collaboration. AG technology is particularly promising for improving academic multi-centre research collaborations. This manuscript describes how the AG technology was utilised by the electronic Primary Care Research Network (ePCRN) that is part of the National Institutes of Health (NIH) Roadmap initiative to improve primary care research and collaboration among practice-based research networks (PBRNs) in the USA. It discusses the design, installation and use of AG implementations, potential future applications, barriers to adoption, and suggested solutions.

Eye movements reveal epistemic curiosity in human observers.

PubMed

Baranes, Adrien; Oudeyer, Pierre-Yves; Gottlieb, Jacqueline

2015-12-01

Saccadic (rapid) eye movements are primary means by which humans and non-human primates sample visual information. However, while saccadic decisions are intensively investigated in instrumental contexts where saccades guide subsequent actions, it is largely unknown how they may be influenced by curiosity - the intrinsic desire to learn. While saccades are sensitive to visual novelty and visual surprise, no study has examined their relation to epistemic curiosity - interest in symbolic, semantic information. To investigate this question, we tracked the eye movements of human observers while they read trivia questions and, after a brief delay, were visually given the answer. We show that higher curiosity was associated with earlier anticipatory orienting of gaze toward the answer location without changes in other metrics of saccades or fixations, and that these influences were distinct from those produced by variations in confidence and surprise. Across subjects, the enhancement of anticipatory gaze was correlated with measures of trait curiosity from personality questionnaires. Finally, a machine learning algorithm could predict curiosity in a cross-subject manner, relying primarily on statistical features of the gaze position before the answer onset and independently of covariations in confidence or surprise, suggesting potential practical applications for educational technologies, recommender systems and research in cognitive sciences. With this article, we provide full access to the annotated database allowing readers to reproduce the results. Epistemic curiosity produces specific effects on oculomotor anticipation that can be used to read out curiosity states. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

PRELIMINARY FACTOR ANALYSIS OF VISUAL COGNITION AND MEMORY. STUDIES IN CINE-PSYCHOMETRY, FINAL REPORT, PART I.

ERIC Educational Resources Information Center

SEIBERT, WARREN F.; AND OTHERS

PRELIMINARY ANALYSES WERE UNDERTAKEN TO DETERMINE THE POTENTIAL CONTRIBUTION OF MOTION PICTURE FILMS TO FACTOR ANALYTIC STUDIES OF HUMAN INTELLECT. OF PRIMARY CONCERN WERE THE OPERATIONS OF COGNITION AND MEMORY, FORMING TWO OF THE FIVE OPERATION COLUMNS OF GUILFORD'S "STRUCTURE OF INTELLECT." THE CORE REFERENCE FOR THE STUDY WAS DEFINED…

Reduced Looming Sensitivity in Primary School Children with Developmental Co-Ordination Disorder

ERIC Educational Resources Information Center

Purcell, Catherine; Wann, John P.; Wilmut, Kate; Poulter, Damian

2012-01-01

Almost all locomotor animals are sensitive to optical expansion (visual looming) and for most animals this sensitivity is evident very early in their development. In humans there is evidence that responses to looming stimuli begin in the first 6 weeks of life, but here we demonstrate that as children become independent their perceptual acuity…

Zebra Stripes through the Eyes of Their Predators, Zebras, and Humans.

PubMed

Melin, Amanda D; Kline, Donald W; Hiramatsu, Chihiro; Caro, Tim

2016-01-01

The century-old idea that stripes make zebras cryptic to large carnivores has never been examined systematically. We evaluated this hypothesis by passing digital images of zebras through species-specific spatial and colour filters to simulate their appearance for the visual systems of zebras' primary predators and zebras themselves. We also measured stripe widths and luminance contrast to estimate the maximum distances from which lions, spotted hyaenas, and zebras can resolve stripes. We found that beyond ca. 50 m (daylight) and 30 m (twilight) zebra stripes are difficult for the estimated visual systems of large carnivores to resolve, but not humans. On moonless nights, stripes are difficult for all species to resolve beyond ca. 9 m. In open treeless habitats where zebras spend most time, zebras are as clearly identified by the lion visual system as are similar-sized ungulates, suggesting that stripes cannot confer crypsis by disrupting the zebra's outline. Stripes confer a minor advantage over solid pelage in masking body shape in woodlands, but the effect is stronger for humans than for predators. Zebras appear to be less able than humans to resolve stripes although they are better than their chief predators. In conclusion, compared to the uniform pelage of other sympatric herbivores it appears highly unlikely that stripes are a form of anti-predator camouflage.

An infrared/video fusion system for military robotics

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

Davis, A.W.; Roberts, R.S.

1997-08-05

Sensory information is critical to the telerobotic operation of mobile robots. In particular, visual sensors are a key component of the sensor package on a robot engaged in urban military operations. Visual sensors provide the robot operator with a wealth of information including robot navigation and threat assessment. However, simple countermeasures such as darkness, smoke, or blinding by a laser, can easily neutralize visual sensors. In order to provide a robust visual sensing system, an infrared sensor is required to augment the primary visual sensor. An infrared sensor can acquire useful imagery in conditions that incapacitate a visual sensor. Amore » simple approach to incorporating an infrared sensor into the visual sensing system is to display two images to the operator: side-by-side visual and infrared images. However, dual images might overwhelm the operator with information, and result in degraded robot performance. A better solution is to combine the visual and infrared images into a single image that maximizes scene information. Fusing visual and infrared images into a single image demands balancing the mixture of visual and infrared information. Humans are accustom to viewing and interpreting visual images. They are not accustom to viewing or interpreting infrared images. Hence, the infrared image must be used to enhance the visual image, not obfuscate it.« less

Lack of Cdkl5 Disrupts the Organization of Excitatory and Inhibitory Synapses and Parvalbumin Interneurons in the Primary Visual Cortex

PubMed Central

Pizzo, Riccardo; Gurgone, Antonia; Castroflorio, Enrico; Amendola, Elena; Gross, Cornelius; Sassoè-Pognetto, Marco; Giustetto, Maurizio

2016-01-01

Cyclin-dependent kinase-like 5 (CDKL5) mutations are found in severe neurodevelopmental disorders, including the Hanefeld variant of Rett syndrome (RTT; CDKL5 disorder). CDKL5 loss-of-function murine models recapitulate pathological signs of the human disease, such as visual attention deficits and reduced visual acuity. Here we investigated the cellular and synaptic substrates of visual defects by studying the organization of the primary visual cortex (V1) of Cdkl5−/y mice. We found a severe reduction of c-Fos expression in V1 of Cdkl5−/y mutants, suggesting circuit hypoactivity. Glutamatergic presynaptic structures were increased, but postsynaptic PSD-95 and Homer were significantly downregulated in CDKL5 mutants. Interneurons expressing parvalbumin, but not other types of interneuron, had a higher density in mutant V1, and were hyperconnected with pyramidal neurons. Finally, the developmental trajectory of pavalbumin-containing cells was also affected in Cdkl5−/y mice, as revealed by fainter appearance perineuronal nets at the closure of the critical period (CP). The present data reveal an overall disruption of V1 cellular and synaptic organization that may cause a shift in the excitation/inhibition balance likely to underlie the visual deficits characteristic of CDKL5 disorder. Moreover, ablation of CDKL5 is likely to tamper with the mechanisms underlying experience-dependent refinement of cortical circuits during the CP of development. PMID:27965538

Blood Oxygen Level-Dependent Activation of the Primary Visual Cortex Predicts Size Adaptation Illusion

PubMed Central

Pooresmaeili, Arezoo; Arrighi, Roberto; Biagi, Laura; Morrone, Maria Concetta

2016-01-01

In natural scenes, objects rarely occur in isolation but appear within a spatiotemporal context. Here, we show that the perceived size of a stimulus is significantly affected by the context of the scene: brief previous presentation of larger or smaller adapting stimuli at the same region of space changes the perceived size of a test stimulus, with larger adapting stimuli causing the test to appear smaller than veridical and vice versa. In a human fMRI study, we measured the blood oxygen level-dependent activation (BOLD) responses of the primary visual cortex (V1) to the contours of large-diameter stimuli and found that activation closely matched the perceptual rather than the retinal stimulus size: the activated area of V1 increased or decreased, depending on the size of the preceding stimulus. A model based on local inhibitory V1 mechanisms simulated the inward or outward shifts of the stimulus contours and hence the perceptual effects. Our findings suggest that area V1 is actively involved in reshaping our perception to match the short-term statistics of the visual scene. PMID:24089504

Multiple Transmitter Receptors in Regions and Layers of the Human Cerebral Cortex

PubMed Central

Zilles, Karl; Palomero-Gallagher, Nicola

2017-01-01

We measured the densities (fmol/mg protein) of 15 different receptors of various transmitter systems in the supragranular, granular and infragranular strata of 44 areas of visual, somatosensory, auditory and multimodal association systems of the human cerebral cortex. Receptor densities were obtained after labeling of the receptors using quantitative in vitro receptor autoradiography in human postmortem brains. The mean density of each receptor type over all cortical layers and of each of the three major strata varies between cortical regions. In a single cortical area, the multi-receptor fingerprints of its strata (i.e., polar plots, each visualizing the densities of multiple different receptor types in supragranular, granular or infragranular layers of the same cortical area) differ in shape and size indicating regional and laminar specific balances between the receptors. Furthermore, the three strata are clearly segregated into well definable clusters by their receptor fingerprints. Fingerprints of different cortical areas systematically vary between functional networks, and with the hierarchical levels within sensory systems. Primary sensory areas are clearly separated from all other cortical areas particularly by their very high muscarinic M2 and nicotinic α4β2 receptor densities, and to a lesser degree also by noradrenergic α2 and serotonergic 5-HT2 receptors. Early visual areas of the dorsal and ventral streams are segregated by their multi-receptor fingerprints. The results are discussed on the background of functional segregation, cortical hierarchies, microstructural types, and the horizontal (layers) and vertical (columns) organization in the cerebral cortex. We conclude that a cortical column is composed of segments, which can be assigned to the cortical strata. The segments differ by their patterns of multi-receptor balances, indicating different layer-specific signal processing mechanisms. Additionally, the differences between the strata-and area-specific fingerprints of the 44 areas reflect the segregation of the cerebral cortex into functionally and topographically definable groups of cortical areas (visual, auditory, somatosensory, limbic, motor), and reveals their hierarchical position (primary and unimodal (early) sensory to higher sensory and finally to multimodal association areas). Highlights Densities of transmitter receptors vary between areas of human cerebral cortex.Multi-receptor fingerprints segregate cortical layers.The densities of all examined receptor types together reach highest values in the supragranular stratum of all areas.The lowest values are found in the infragranular stratum.Multi-receptor fingerprints of entire areas and their layers segregate functional systemsCortical types (primary sensory, motor, multimodal association) differ in their receptor fingerprints. PMID:28970785

Recent Visual Experience Shapes Visual Processing in Rats through Stimulus-Specific Adaptation and Response Enhancement.

PubMed

Vinken, Kasper; Vogels, Rufin; Op de Beeck, Hans

2017-03-20

From an ecological point of view, it is generally suggested that the main goal of vision in rats and mice is navigation and (aerial) predator evasion [1-3]. The latter requires fast and accurate detection of a change in the visual environment. An outstanding question is whether there are mechanisms in the rodent visual system that would support and facilitate visual change detection. An experimental protocol frequently used to investigate change detection in humans is the oddball paradigm, in which a rare, unexpected stimulus is presented in a train of stimulus repetitions [4]. A popular "predictive coding" theory of cortical responses states that neural responses should decrease for expected sensory input and increase for unexpected input [5, 6]. Despite evidence for response suppression and enhancement in noninvasive scalp recordings in humans with this paradigm [7, 8], it has proven challenging to observe both phenomena in invasive action potential recordings in other animals [9-11]. During a visual oddball experiment, we recorded multi-unit spiking activity in rat primary visual cortex (V1) and latero-intermediate area (LI), which is a higher area of the rodent ventral visual stream. In rat V1, there was only evidence for response suppression related to stimulus-specific adaptation, and not for response enhancement. However, higher up in area LI, spiking activity showed clear surprise-based response enhancement in addition to stimulus-specific adaptation. These results show that neural responses along the rat ventral visual stream become increasingly sensitive to changes in the visual environment, suggesting a system specialized in the detection of unexpected events. Copyright © 2017 Elsevier Ltd. All rights reserved.

Exploring associations between gaze patterns and putative human mirror neuron system activity.

PubMed

Donaldson, Peter H; Gurvich, Caroline; Fielding, Joanne; Enticott, Peter G

2015-01-01

The human mirror neuron system (MNS) is hypothesized to be crucial to social cognition. Given that key MNS-input regions such as the superior temporal sulcus are involved in biological motion processing, and mirror neuron activity in monkeys has been shown to vary with visual attention, aberrant MNS function may be partly attributable to atypical visual input. To examine the relationship between gaze pattern and interpersonal motor resonance (IMR; an index of putative MNS activity), healthy right-handed participants aged 18-40 (n = 26) viewed videos of transitive grasping actions or static hands, whilst the left primary motor cortex received transcranial magnetic stimulation. Motor-evoked potentials recorded in contralateral hand muscles were used to determine IMR. Participants also underwent eyetracking analysis to assess gaze patterns whilst viewing the same videos. No relationship was observed between predictive gaze and IMR. However, IMR was positively associated with fixation counts in areas of biological motion in the videos, and negatively associated with object areas. These findings are discussed with reference to visual influences on the MNS, and the possibility that MNS atypicalities might be influenced by visual processes such as aberrant gaze pattern.

Cortical Neural Synchronization Underlies Primary Visual Consciousness of Qualia: Evidence from Event-Related Potentials

PubMed Central

Babiloni, Claudio; Marzano, Nicola; Soricelli, Andrea; Cordone, Susanna; Millán-Calenti, José Carlos; Del Percio, Claudio; Buján, Ana

2016-01-01

This article reviews three experiments on event-related potentials (ERPs) testing the hypothesis that primary visual consciousness (stimulus self-report) is related to enhanced cortical neural synchronization as a function of stimulus features. ERP peak latency and sources were compared between “seen” trials and “not seen” trials, respectively related and unrelated to the primary visual consciousness. Three salient features of visual stimuli were considered (visuospatial, emotional face expression, and written words). Results showed the typical visual ERP components in both “seen” and “not seen” trials. There was no statistical difference in the ERP peak latencies between the “seen” and “not seen” trials, suggesting a similar timing of the cortical neural synchronization regardless the primary visual consciousness. In contrast, ERP sources showed differences between “seen” and “not seen” trials. For the visuospatial stimuli, the primary consciousness was related to higher activity in dorsal occipital and parietal sources at about 400 ms post-stimulus. For the emotional face expressions, there was greater activity in parietal and frontal sources at about 180 ms post-stimulus. For the written letters, there was higher activity in occipital, parietal and temporal sources at about 230 ms post-stimulus. These results hint that primary visual consciousness is associated with an enhanced cortical neural synchronization having entirely different spatiotemporal characteristics as a function of the features of the visual stimuli and possibly, the relative qualia (i.e., visuospatial, face expression, and words). In this framework, the dorsal visual stream may be synchronized in association with the primary consciousness of visuospatial and emotional face contents. Analogously, both dorsal and ventral visual streams may be synchronized in association with the primary consciousness of linguistic contents. In this line of reasoning, the ensemble of the cortical neural networks underpinning the single visual features would constitute a sort of multi-dimensional palette of colors, shapes, regions of the visual field, movements, emotional face expressions, and words. The synchronization of one or more of these cortical neural networks, each with its peculiar timing, would produce the primary consciousness of one or more of the visual features of the scene. PMID:27445750

Sequential roles of primary somatosensory cortex and posterior parietal cortex in tactile-visual cross-modal working memory: a single-pulse transcranial magnetic stimulation (spTMS) study.

PubMed

Ku, Yixuan; Zhao, Di; Hao, Ning; Hu, Yi; Bodner, Mark; Zhou, Yong-Di

2015-01-01

Both monkey neurophysiological and human EEG studies have shown that association cortices, as well as primary sensory cortical areas, play an essential role in sequential neural processes underlying cross-modal working memory. The present study aims to further examine causal and sequential roles of the primary sensory cortex and association cortex in cross-modal working memory. Individual MRI-based single-pulse transcranial magnetic stimulation (spTMS) was applied to bilateral primary somatosensory cortices (SI) and the contralateral posterior parietal cortex (PPC), while participants were performing a tactile-visual cross-modal delayed matching-to-sample task. Time points of spTMS were 300 ms, 600 ms, 900 ms after the onset of the tactile sample stimulus in the task. The accuracy of task performance and reaction time were significantly impaired when spTMS was applied to the contralateral SI at 300 ms. Significant impairment on performance accuracy was also observed when the contralateral PPC was stimulated at 600 ms. SI and PPC play sequential and distinct roles in neural processes of cross-modal associations and working memory. Copyright © 2015 Elsevier Inc. All rights reserved.

Predictive factors of visual function recovery after pituitary adenoma resection: a literature review and Meta-analysis.

PubMed

Sun, Min; Zhang, Zhi-Qiang; Ma, Chi-Yuan; Chen, Sui-Hua; Chen, Xin-Jian

2017-01-01

To determine the dominant predictive factors of postoperative visual recovery for patients with pituitary adenoma. PubMed, Google Scholar, Web of Science and Cochrane Library were searched for relevant human studies, which investigated the prediction of the postoperative visual recovery of patients with pituitary adenoma, from January 2000 to May 2017. Meta-analyses were performed on the primary outcomes. After the related data were extracted by two independent investigators, pooled weighted mean difference (WMD) and odds ratio (OR) with 95% confidence interval (CI) were estimated using a random-effects or a fixed-effects model. Nineteen studies were included in the literature review, and nine trials were included in the Meta-analysis, which comprised 530 patients (975 eyes) with pituitary adenoma. For the primary outcomes, there was a significant difference between preoperative and postoperative mean deviation (MD) values of the visual field (WMD -5.85; 95%CI: -8.19 to -3.51; P <0.00001). Predictive characteristics of four factors were revealed in this Meta-analysis by assigning the patients to sufficient and insufficient groups according to postoperative visual field improvements, including preoperative visual field defect (WMD 10.09; 95%CI: 6.17 to 14.02; P <0.00001), patient age (WMD -12.32; 95%CI: -18.42 to -6.22; P <0.0001), symptom duration (WMD -5.04; 95%CI: -9.71 to -0.37; P =0.03), and preoperative peripapillary retinal nerve fiber layer (pRNFL) thickness (OR 0.1; 95% CI: 0.04 to 0.23; P <0.00001). Preoperative visual field defect, symptom duration, patient age, and preoperative pRNFL thickness are the dominant predictive factors of the postoperative recovery of the visual field for patients with pituitary adenoma.

Primary structure and functional characterization of a Drosophila dopamine receptor with high homology to human D1/5 receptors.

PubMed

Gotzes, F; Balfanz, S; Baumann, A

1994-01-01

Members of the superfamily of G-protein coupled receptors share significant similarities in sequence and transmembrane architecture. We have isolated a Drosophila homologue of the mammalian dopamine receptor family using a low stringency hybridization approach. The deduced amino acid sequence is approximately 70% homologous to the human D1/D5 receptors. When expressed in HEK 293 cells, the Drosophila receptor stimulates cAMP production in response to dopamine application. This effect was mimicked by SKF 38393, a specific D1 receptor agonist, but inhibited by dopaminergic antagonists such as butaclamol and flupentixol. In situ hybridization revealed that the Drosophila dopamine receptor is highly expressed in the somata of the optic lobes. This suggests that the receptor might be involved in the processing of visual information and/or visual learning in invertebrates.

Pyramid image codes

NASA Technical Reports Server (NTRS)

Watson, Andrew B.

1990-01-01

All vision systems, both human and machine, transform the spatial image into a coded representation. Particular codes may be optimized for efficiency or to extract useful image features. Researchers explored image codes based on primary visual cortex in man and other primates. Understanding these codes will advance the art in image coding, autonomous vision, and computational human factors. In cortex, imagery is coded by features that vary in size, orientation, and position. Researchers have devised a mathematical model of this transformation, called the Hexagonal oriented Orthogonal quadrature Pyramid (HOP). In a pyramid code, features are segregated by size into layers, with fewer features in the layers devoted to large features. Pyramid schemes provide scale invariance, and are useful for coarse-to-fine searching and for progressive transmission of images. The HOP Pyramid is novel in three respects: (1) it uses a hexagonal pixel lattice, (2) it uses oriented features, and (3) it accurately models most of the prominent aspects of primary visual cortex. The transform uses seven basic features (kernels), which may be regarded as three oriented edges, three oriented bars, and one non-oriented blob. Application of these kernels to non-overlapping seven-pixel neighborhoods yields six oriented, high-pass pyramid layers, and one low-pass (blob) layer.

Haptic perception and body representation in lateral and medial occipito-temporal cortices.

PubMed

Costantini, Marcello; Urgesi, Cosimo; Galati, Gaspare; Romani, Gian Luca; Aglioti, Salvatore M

2011-04-01

Although vision is the primary sensory modality that humans and other primates use to identify objects in the environment, we can recognize crucial object features (e.g., shape, size) using the somatic modality. Previous studies have shown that the occipito-temporal areas dedicated to the visual processing of object forms, faces and bodies also show category-selective responses when the preferred stimuli are haptically explored out of view. Visual processing of human bodies engages specific areas in lateral (extrastriate body area, EBA) and medial (fusiform body area, FBA) occipito-temporal cortex. This study aimed at exploring the relative involvement of EBA and FBA in the haptic exploration of body parts. During fMRI scanning, participants were asked to haptically explore either real-size fake body parts or objects. We found a selective activation of right and left EBA, but not of right FBA, while participants haptically explored body parts as compared to real objects. This suggests that EBA may integrate visual body representations with somatosensory information regarding body parts and form a multimodal representation of the body. Furthermore, both left and right EBA showed a comparable level of body selectivity during haptic perception and visual imagery. However, right but not left EBA was more activated during haptic exploration than visual imagery of body parts, ruling out that the response to haptic body exploration was entirely due to the use of visual imagery. Overall, the results point to the existence of different multimodal body representations in the occipito-temporal cortex which are activated during perception and imagery of human body parts. Copyright © 2011 Elsevier Ltd. All rights reserved.

Priming with real motion biases visual cortical response to bistable apparent motion

PubMed Central

Zhang, Qing-fang; Wen, Yunqing; Zhang, Deng; She, Liang; Wu, Jian-young; Dan, Yang; Poo, Mu-ming

2012-01-01

Apparent motion quartet is an ambiguous stimulus that elicits bistable perception, with the perceived motion alternating between two orthogonal paths. In human psychophysical experiments, the probability of perceiving motion in each path is greatly enhanced by a brief exposure to real motion along that path. To examine the neural mechanism underlying this priming effect, we used voltage-sensitive dye (VSD) imaging to measure the spatiotemporal activity in the primary visual cortex (V1) of awake mice. We found that a brief real motion stimulus transiently biased the cortical response to subsequent apparent motion toward the spatiotemporal pattern representing the real motion. Furthermore, intracellular recording from V1 neurons in anesthetized mice showed a similar increase in subthreshold depolarization in the neurons representing the path of real motion. Such short-term plasticity in early visual circuits may contribute to the priming effect in bistable visual perception. PMID:23188797

Early suppression effect in human primary visual cortex during Kanizsa illusion processing: A magnetoencephalographic evidence.

PubMed

Chernyshev, Boris V; Pronko, Platon K; Stroganova, Tatiana A

2016-01-01

Detection of illusory contours (ICs) such as Kanizsa figures is known to depend primarily upon the lateral occipital complex. Yet there is no universal agreement on the role of the primary visual cortex in this process; some existing evidence hints that an early stage of the visual response in V1 may involve relative suppression to Kanizsa figures compared with controls. Iso-oriented luminance borders, which are responsible for Kanizsa illusion, may evoke surround suppression in V1 and adjacent areas leading to the reduction in the initial response to Kanizsa figures. We attempted to test the existence, as well as to find localization and timing of the early suppression effect produced by Kanizsa figures in adult nonclinical human participants. We used two sizes of visual stimuli (4.5 and 9.0°) in order to probe the effect at two different levels of eccentricity; the stimuli were presented centrally in passive viewing conditions. We recorded magnetoencephalogram, which is more sensitive than electroencephalogram to activity originating from V1 and V2 areas. We restricted our analysis to the medial occipital area and the occipital pole, and to a 40-120 ms time window after the stimulus onset. By applying threshold-free cluster enhancement technique in combination with permutation statistics, we were able to detect the inverted IC effect-a relative suppression of the response to the Kanizsa figures compared with the control stimuli. The current finding is highly compatible with the explanation involving surround suppression evoked by iso-oriented collinear borders. The effect may be related to the principle of sparse coding, according to which V1 suppresses representations of inner parts of collinear assemblies as being informationally redundant. Such a mechanism is likely to be an important preliminary step preceding object contour detection.

Evidence that primary visual cortex is required for image, orientation, and motion discrimination by rats.

PubMed

Petruno, Sarah K; Clark, Robert E; Reinagel, Pamela

2013-01-01

The pigmented Long-Evans rat has proven to be an excellent subject for studying visually guided behavior including quantitative visual psychophysics. This observation, together with its experimental accessibility and its close homology to the mouse, has made it an attractive model system in which to dissect the thalamic and cortical circuits underlying visual perception. Given that visually guided behavior in the absence of primary visual cortex has been described in the literature, however, it is an empirical question whether specific visual behaviors will depend on primary visual cortex in the rat. Here we tested the effects of cortical lesions on performance of two-alternative forced-choice visual discriminations by Long-Evans rats. We present data from one highly informative subject that learned several visual tasks and then received a bilateral lesion ablating >90% of primary visual cortex. After the lesion, this subject had a profound and persistent deficit in complex image discrimination, orientation discrimination, and full-field optic flow motion discrimination, compared with both pre-lesion performance and sham-lesion controls. Performance was intact, however, on another visual two-alternative forced-choice task that required approaching a salient visual target. A second highly informative subject learned several visual tasks prior to receiving a lesion ablating >90% of medial extrastriate cortex. This subject showed no impairment on any of the four task categories. Taken together, our data provide evidence that these image, orientation, and motion discrimination tasks require primary visual cortex in the Long-Evans rat, whereas approaching a salient visual target does not.

From genes to brain oscillations: is the visual pathway the epigenetic clue to schizophrenia?

PubMed

González-Hernández, J A; Pita-Alcorta, C; Cedeño, I R

2006-01-01

Molecular data and gene expression data and recently mitochondrial genes and possible epigenetic regulation by non-coding genes is revolutionizing our views on schizophrenia. Genes and epigenetic mechanisms are triggered by cell-cell interaction and by external stimuli. A number of recent clinical and molecular observations indicate that epigenetic factors may be operational in the origin of the illness. Based on the molecular insights, gene expression profiles and epigenetic regulation of gene, we went back to the neurophysiology (brain oscillations) and found a putative role of the visual experiences (i.e. visual stimuli) as epigenetic factor. The functional evidences provided here, establish a direct link between the striate and extrastriate unimodal visual cortex and the neurobiology of the schizophrenia. This result support the hypothesis that 'visual experience' has a potential role as epigenetic factor and contribute to trigger and/or to maintain the progression of the schizophrenia. In this case, candidate genes sensible for the visual 'insult' may be located within the visual cortex including associative areas, while the integrity of the visual pathway before reaching the primary visual cortex is preserved. The same effect can be perceived if target genes are localised within the visual pathway, which actually, is more sensitive for 'insult' during the early life than the cortex per se. If this process affects gene expression at these sites a stably sensory specific 'insult', i.e. distorted visual information, is entering the visual system and expanded to fronto-temporo-parietal multimodal areas even from early maturation periods. The difference in the timing of postnatal neuroanatomical events between such areas and the primary visual cortex in humans (with the formers reaching the same development landmarks later in life than the latter) is 'optimal' to establish an abnormal 'cell- communication' mediated by the visual system that may further interfere with the local physiology. In this context the strategy to search target genes need to be rearrangement and redirected to visual-related genes. Otherwise, psychophysics studies combining functional neuroimage, and electrophysiology are strongly recommended, for the search of epigenetic clues that will allow to carrier gene association studies in schizophrenia.

Model Cortical Association Fields Account for the Time Course and Dependence on Target Complexity of Human Contour Perception

PubMed Central

Gintautas, Vadas; Ham, Michael I.; Kunsberg, Benjamin; Barr, Shawn; Brumby, Steven P.; Rasmussen, Craig; George, John S.; Nemenman, Ilya; Bettencourt, Luís M. A.; Kenyon, Garret T.

2011-01-01

Can lateral connectivity in the primary visual cortex account for the time dependence and intrinsic task difficulty of human contour detection? To answer this question, we created a synthetic image set that prevents sole reliance on either low-level visual features or high-level context for the detection of target objects. Rendered images consist of smoothly varying, globally aligned contour fragments (amoebas) distributed among groups of randomly rotated fragments (clutter). The time course and accuracy of amoeba detection by humans was measured using a two-alternative forced choice protocol with self-reported confidence and variable image presentation time (20-200 ms), followed by an image mask optimized so as to interrupt visual processing. Measured psychometric functions were well fit by sigmoidal functions with exponential time constants of 30-91 ms, depending on amoeba complexity. Key aspects of the psychophysical experiments were accounted for by a computational network model, in which simulated responses across retinotopic arrays of orientation-selective elements were modulated by cortical association fields, represented as multiplicative kernels computed from the differences in pairwise edge statistics between target and distractor images. Comparing the experimental and the computational results suggests that each iteration of the lateral interactions takes at least ms of cortical processing time. Our results provide evidence that cortical association fields between orientation selective elements in early visual areas can account for important temporal and task-dependent aspects of the psychometric curves characterizing human contour perception, with the remaining discrepancies postulated to arise from the influence of higher cortical areas. PMID:21998562

Anthropological film: a scientific and humanistic resource.

PubMed

Soren, E R

1974-12-20

More than a scientific endeavor but not strictly one of the humanities either, anthropology stands between these basic kinds of intellectual pursuit, bridging and contributing to both. Not limited to natural history, anthropology touches art, historical process, and human values, drawing from the materials and approaches of both science and humanities. This professional interest in a broad understanding of the human condition has led anthropologists to adapt and use modern cameras and films to inquire further into the variety of ways of life of mankind and to develop method and theory to prepare anthropological film as a permanent scientific and humanistic resource. Until quite recently the evolution of human culture and organization has diverged in the hitherto isolated regions of the world. Now this divergence has virtually ceased; we are witnessing an unprecedented period in human history-one where cultural divergence has turned to cultural convergence and where the varieties of independently evolved expressions of basic human potential are giving way to a single system of modern communications, transport, commerce, and manufacturing technology. Before the varieties of ways of life of the world disappear, they can be preserved in facsimile in anthropological films. As primary, undifferentiated visual information, these films facilitate that early step in the creation of new knowledge which is sometimes called humanistic and without which scientific application lies dormant, lacking an idea to test. In keeping with the two scholarly faces of anthropology, humanistic and scientific, anthropological films may provide material permitting both humanistic insight and the more controlled formulations of science. The lightweight filming equipment recently developed has been adapted by anthropologists as a tool of scholarly visual inquiry; methods of retrieving visual data from changing and vanishing ways of life have been developed; and new ways to reveal human beings to one another by using such visual resources have been explored. As a result, not only can anthropological film records permit continued reexamination of the past human conditions from which the present was shaped, but they also facilitate an ongoing public and scientific review of the dynamics of the human behavioral and social repertoire in relation to the contemporary conditions which pattern human responses and adaptation. How man fits into and copes with the changing world is of vital interest and concern. Visual data provide otherwise unobtainable information on human potential, behavior, and social organization. Such information, fed into the public media, facilitates informed consideration of alternative possibilities. By contributing to a better informed society, such films will help make our future more human and more humane.

Visual Thinking in Teaching History: Reading the Visual Thinking Skills of 12 Year-Old Pupils in Istanbul

ERIC Educational Resources Information Center

Dilek, Gulcin

2010-01-01

This study aims to explore the visual thinking skills of some sixth grade (12-13 year-old) primary pupils who created visual interpretations during history courses. Pupils drew pictures describing historical scenes or events based on visual sources. They constructed these illustrations by using visual and written primary and secondary sources in…

Long-Lasting Crossmodal Cortical Reorganization Triggered by Brief Postnatal Visual Deprivation.

PubMed

Collignon, Olivier; Dormal, Giulia; de Heering, Adelaide; Lepore, Franco; Lewis, Terri L; Maurer, Daphne

2015-09-21

Animal and human studies have demonstrated that transient visual deprivation early in life, even for a very short period, permanently alters the response properties of neurons in the visual cortex and leads to corresponding behavioral visual deficits. While it is acknowledged that early-onset and longstanding blindness leads the occipital cortex to respond to non-visual stimulation, it remains unknown whether a short and transient period of postnatal visual deprivation is sufficient to trigger crossmodal reorganization that persists after years of visual experience. In the present study, we characterized brain responses to auditory stimuli in 11 adults who had been deprived of all patterned vision at birth by congenital cataracts in both eyes until they were treated at 9 to 238 days of age. When compared to controls with typical visual experience, the cataract-reversal group showed enhanced auditory-driven activity in focal visual regions. A combination of dynamic causal modeling with Bayesian model selection indicated that this auditory-driven activity in the occipital cortex was better explained by direct cortico-cortical connections with the primary auditory cortex than by subcortical connections. Thus, a short and transient period of visual deprivation early in life leads to enduring large-scale crossmodal reorganization of the brain circuitry typically dedicated to vision. Copyright © 2015 Elsevier Ltd. All rights reserved.

From attentional gating in macaque primary visual cortex to dyslexia in humans.

PubMed

Vidyasagar, T R

2001-01-01

Selective attention is an important aspect of brain function that we need in coping with the immense and constant barrage of sensory information. One model of attention (Feature Integration Theory) that suggests an early selection of spatial locations of objects via an attentional spotlight would also solve the 'binding problem' (that is how do different attributes of each object get correctly bound together?). Our experiments have demonstrated modulation of specific locations of interest at the level of the primary visual cortex both in visual discrimination and memory tasks, where the actual locations of the targets was also important in being able to perform the task. It is suggested that the feedback mediating the modulation arises from the posterior parietal cortex, which would also be consistent with its known role in attentional control. In primates, the magnocellular (M) and parvocellular (P) pathways are the two major streams of inputs from the retina, carrying distinctly different types of information and they remain fairly segregated in their projections to the primary visual cortex and further into the extra-striate regions. The P inputs go mainly into the ventral (temporal) stream, while the dorsal (parietal) stream is dominated by M inputs. A theory of attentional gating is proposed here where the M dominated dorsal stream gates the P inputs into the ventral stream. This framework is used to provide a neural explanation of the processes involved in reading and in learning to read. This scheme also explains how a magnocellular deficit could cause the common reading impairment, dyslexia.

Prospective, observational study comparing automated and visual point-of-care urinalysis in general practice.

PubMed

van Delft, Sanne; Goedhart, Annelijn; Spigt, Mark; van Pinxteren, Bart; de Wit, Niek; Hopstaken, Rogier

2016-08-08

Point-of-care testing (POCT) urinalysis might reduce errors in (subjective) reading, registration and communication of test results, and might also improve diagnostic outcome and optimise patient management. Evidence is lacking. In the present study, we have studied the analytical performance of automated urinalysis and visual urinalysis compared with a reference standard in routine general practice. The study was performed in six general practitioner (GP) group practices in the Netherlands. Automated urinalysis was compared with visual urinalysis in these practices. Reference testing was performed in a primary care laboratory (Saltro, Utrecht, The Netherlands). Analytical performance of automated and visual urinalysis compared with the reference laboratory method was the primary outcome measure, analysed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and Cohen's κ coefficient for agreement. Secondary outcome measure was the user-friendliness of the POCT analyser. Automated urinalysis by experienced and routinely trained practice assistants in general practice performs as good as visual urinalysis for nitrite, leucocytes and erythrocytes. Agreement for nitrite is high for automated and visual urinalysis. κ's are 0.824 and 0.803 (ranked as very good and good, respectively). Agreement with the central laboratory reference standard for automated and visual urinalysis for leucocytes is rather poor (0.256 for POCT and 0.197 for visual, respectively, ranked as fair and poor). κ's for erythrocytes are higher: 0.517 (automated) and 0.416 (visual), both ranked as moderate. The Urisys 1100 analyser was easy to use and considered to be not prone to flaws. Automated urinalysis performed as good as traditional visual urinalysis on reading of nitrite, leucocytes and erythrocytes in routine general practice. Implementation of automated urinalysis in general practice is justified as automation is expected to reduce human errors in patient identification and transcribing of results. 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/

Inferring the direction of implied motion depends on visual awareness

PubMed Central

Faivre, Nathan; Koch, Christof

2014-01-01

Visual awareness of an event, object, or scene is, by essence, an integrated experience, whereby different visual features composing an object (e.g., orientation, color, shape) appear as an unified percept and are processed as a whole. Here, we tested in human observers whether perceptual integration of static motion cues depends on awareness by measuring the capacity to infer the direction of motion implied by a static visible or invisible image under continuous flash suppression. Using measures of directional adaptation, we found that visible but not invisible implied motion adaptors biased the perception of real motion probes. In a control experiment, we found that invisible adaptors implying motion primed the perception of subsequent probes when they were identical (i.e., repetition priming), but not when they only shared the same direction (i.e., direction priming). Furthermore, using a model of visual processing, we argue that repetition priming effects are likely to arise as early as in the primary visual cortex. We conclude that although invisible images implying motion undergo some form of nonconscious processing, visual awareness is necessary to make inferences about motion direction. PMID:24706951

Inferring the direction of implied motion depends on visual awareness.

PubMed

Faivre, Nathan; Koch, Christof

2014-04-04

Visual awareness of an event, object, or scene is, by essence, an integrated experience, whereby different visual features composing an object (e.g., orientation, color, shape) appear as an unified percept and are processed as a whole. Here, we tested in human observers whether perceptual integration of static motion cues depends on awareness by measuring the capacity to infer the direction of motion implied by a static visible or invisible image under continuous flash suppression. Using measures of directional adaptation, we found that visible but not invisible implied motion adaptors biased the perception of real motion probes. In a control experiment, we found that invisible adaptors implying motion primed the perception of subsequent probes when they were identical (i.e., repetition priming), but not when they only shared the same direction (i.e., direction priming). Furthermore, using a model of visual processing, we argue that repetition priming effects are likely to arise as early as in the primary visual cortex. We conclude that although invisible images implying motion undergo some form of nonconscious processing, visual awareness is necessary to make inferences about motion direction.

Zebra Stripes through the Eyes of Their Predators, Zebras, and Humans

PubMed Central

Melin, Amanda D.; Kline, Donald W.; Hiramatsu, Chihiro; Caro, Tim

2016-01-01

The century-old idea that stripes make zebras cryptic to large carnivores has never been examined systematically. We evaluated this hypothesis by passing digital images of zebras through species-specific spatial and colour filters to simulate their appearance for the visual systems of zebras’ primary predators and zebras themselves. We also measured stripe widths and luminance contrast to estimate the maximum distances from which lions, spotted hyaenas, and zebras can resolve stripes. We found that beyond ca. 50 m (daylight) and 30 m (twilight) zebra stripes are difficult for the estimated visual systems of large carnivores to resolve, but not humans. On moonless nights, stripes are difficult for all species to resolve beyond ca. 9 m. In open treeless habitats where zebras spend most time, zebras are as clearly identified by the lion visual system as are similar-sized ungulates, suggesting that stripes cannot confer crypsis by disrupting the zebra’s outline. Stripes confer a minor advantage over solid pelage in masking body shape in woodlands, but the effect is stronger for humans than for predators. Zebras appear to be less able than humans to resolve stripes although they are better than their chief predators. In conclusion, compared to the uniform pelage of other sympatric herbivores it appears highly unlikely that stripes are a form of anti-predator camouflage. PMID:26799935

Scene and human face recognition in the central vision of patients with glaucoma

PubMed Central

Aptel, Florent; Attye, Arnaud; Guyader, Nathalie; Boucart, Muriel; Chiquet, Christophe; Peyrin, Carole

2018-01-01

Primary open-angle glaucoma (POAG) firstly mainly affects peripheral vision. Current behavioral studies support the idea that visual defects of patients with POAG extend into parts of the central visual field classified as normal by static automated perimetry analysis. This is particularly true for visual tasks involving processes of a higher level than mere detection. The purpose of this study was to assess visual abilities of POAG patients in central vision. Patients were assigned to two groups following a visual field examination (Humphrey 24–2 SITA-Standard test). Patients with both peripheral and central defects and patients with peripheral but no central defect, as well as age-matched controls, participated in the experiment. All participants had to perform two visual tasks where low-contrast stimuli were presented in the central 6° of the visual field. A categorization task of scene images and human face images assessed high-level visual recognition abilities. In contrast, a detection task using the same stimuli assessed low-level visual function. The difference in performance between detection and categorization revealed the cost of high-level visual processing. Compared to controls, patients with a central visual defect showed a deficit in both detection and categorization of all low-contrast images. This is consistent with the abnormal retinal sensitivity as assessed by perimetry. However, the deficit was greater for categorization than detection. Patients without a central defect showed similar performances to the controls concerning the detection and categorization of faces. However, while the detection of scene images was well-maintained, these patients showed a deficit in their categorization. This suggests that the simple loss of peripheral vision could be detrimental to scene recognition, even when the information is displayed in central vision. This study revealed subtle defects in the central visual field of POAG patients that cannot be predicted by static automated perimetry assessment using Humphrey 24–2 SITA-Standard test. PMID:29481572

Novel Application of Postmortem CT Angiography for Evaluation of the Intracranial Vascular Anatomy in Cadaver Heads.

PubMed

van Eijk, Ruben P A; van der Zwan, Albert; Bleys, Ronald L A W; Regli, Luca; Esposito, Giuseppe

2015-12-01

Postmortem CT angiography is a common procedure used to visualize the entire human vasculature. For visualization of a specific organ's vascular anatomy, casting is the preferred method. Because of the permanent and damaging nature of casting, the organ cannot be further used as an experimental model after angiography. Therefore, there is a need for a minimally traumatic method to visualize organ-specific vascular anatomy. The purpose of this study was to develop and evaluate a contrast enhancement technique that is capable of visualizing the intracranial vascular anatomy while preserving the anatomic integrity in cadaver heads. Seven human heads were used in this study. Heads were prepared by cannulating the vertebral and internal carotid arteries. Contrast agent was injected as a mixture of tap water, polyethylene glycol 600, and an iodinated contrast agent. Postmortem imaging was executed on a 64-MDCT scanner. Primary image review and 3D reconstruction were performed on a CT workstation. Clear visualization of the major cerebral arteries and smaller intracranial branches was achieved. Adequate visualization was obtained for both the anterior and posterior intracranial circulation. The minimally traumatic angiography method preserved the vascular integrity of the cadaver heads. A novel application of postmortem CT angiography is presented here. The technique can be used for radiologic evaluation of the intracranial circulation in cadaver heads. After CT angiography, the specimen can be used for further experimental or laboratory testing and teaching purposes.

Identifying the computational requirements of an integrated top-down-bottom-up model for overt visual attention within an active vision system.

PubMed

McBride, Sebastian; Huelse, Martin; Lee, Mark

2013-01-01

Computational visual attention systems have been constructed in order for robots and other devices to detect and locate regions of interest in their visual world. Such systems often attempt to take account of what is known of the human visual system and employ concepts, such as 'active vision', to gain various perceived advantages. However, despite the potential for gaining insights from such experiments, the computational requirements for visual attention processing are often not clearly presented from a biological perspective. This was the primary objective of this study, attained through two specific phases of investigation: 1) conceptual modeling of a top-down-bottom-up framework through critical analysis of the psychophysical and neurophysiological literature, 2) implementation and validation of the model into robotic hardware (as a representative of an active vision system). Seven computational requirements were identified: 1) transformation of retinotopic to egocentric mappings, 2) spatial memory for the purposes of medium-term inhibition of return, 3) synchronization of 'where' and 'what' information from the two visual streams, 4) convergence of top-down and bottom-up information to a centralized point of information processing, 5) a threshold function to elicit saccade action, 6) a function to represent task relevance as a ratio of excitation and inhibition, and 7) derivation of excitation and inhibition values from object-associated feature classes. The model provides further insight into the nature of data representation and transfer between brain regions associated with the vertebrate 'active' visual attention system. In particular, the model lends strong support to the functional role of the lateral intraparietal region of the brain as a primary area of information consolidation that directs putative action through the use of a 'priority map'.

Identifying the Computational Requirements of an Integrated Top-Down-Bottom-Up Model for Overt Visual Attention within an Active Vision System

PubMed Central

McBride, Sebastian; Huelse, Martin; Lee, Mark

2013-01-01

Computational visual attention systems have been constructed in order for robots and other devices to detect and locate regions of interest in their visual world. Such systems often attempt to take account of what is known of the human visual system and employ concepts, such as ‘active vision’, to gain various perceived advantages. However, despite the potential for gaining insights from such experiments, the computational requirements for visual attention processing are often not clearly presented from a biological perspective. This was the primary objective of this study, attained through two specific phases of investigation: 1) conceptual modeling of a top-down-bottom-up framework through critical analysis of the psychophysical and neurophysiological literature, 2) implementation and validation of the model into robotic hardware (as a representative of an active vision system). Seven computational requirements were identified: 1) transformation of retinotopic to egocentric mappings, 2) spatial memory for the purposes of medium-term inhibition of return, 3) synchronization of ‘where’ and ‘what’ information from the two visual streams, 4) convergence of top-down and bottom-up information to a centralized point of information processing, 5) a threshold function to elicit saccade action, 6) a function to represent task relevance as a ratio of excitation and inhibition, and 7) derivation of excitation and inhibition values from object-associated feature classes. The model provides further insight into the nature of data representation and transfer between brain regions associated with the vertebrate ‘active’ visual attention system. In particular, the model lends strong support to the functional role of the lateral intraparietal region of the brain as a primary area of information consolidation that directs putative action through the use of a ‘priority map’. PMID:23437044

Compression and reflection of visually evoked cortical waves

PubMed Central

Xu, Weifeng; Huang, Xiaoying; Takagaki, Kentaroh; Wu, Jian-young

2007-01-01

Summary Neuronal interactions between primary and secondary visual cortical areas are important for visual processing, but the spatiotemporal patterns of the interaction are not well understood. We used voltage-sensitive dye imaging to visualize neuronal activity in rat visual cortex and found novel visually evoked waves propagating from V1 to other visual areas. A primary wave originated in the monocular area of V1 and was “compressed” when propagating to V2. A reflected wave initiated after compression and propagated backward into V1. The compression occurred at the V1/V2 border, and local GABAA inhibition is important for the compression. The compression/reflection pattern provides a two-phase modulation: V1 is first depolarized by the primary wave and then V1 and V2 are simultaneously depolarized by the reflected and primary waves, respectively. The compression/reflection pattern only occurred for evoked but not for spontaneous waves, suggesting that it is organized by an internal mechanism associated with visual processing. PMID:17610821

The uncertain response in humans and animals

NASA Technical Reports Server (NTRS)

Smith, J. D.; Shields, W. E.; Schull, J.; Washburn, D. A.; Rumbaugh, D. M. (Principal Investigator)

1997-01-01

There has been no comparative psychological study of uncertainty processes. Accordingly, the present experiments asked whether animals, like humans, escape adaptively when they are uncertain. Human and animal observers were given two primary responses in a visual discrimination task, and the opportunity to escape from some trials into easier ones. In one psychophysical task (using a threshold paradigm), humans escaped selectively the difficult trials that left them uncertain of the stimulus. Two rhesus monkeys (Macaca mulatta) also showed this pattern. In a second psychophysical task (using the method of constant stimuli), some humans showed this pattern but one escaped infrequently and nonoptimally. Monkeys showed equivalent individual differences. The data suggest that escapes by humans and monkeys are interesting cognitive analogs and may reflect controlled decisional processes prompted by the perceptual ambiguity at threshold.

NPS AUV Integrated Simulator

DTIC Science & Technology

1992-03-01

provided underwater photography, pool test support, boundless knowledge about how to make things work and enthusiastic encouragement. He and Walt...fundamentalprinciples and difficulties. The primary problem addressed by this thesis is how to design and construct an integrated simulator in order to ...improves our understanding of how things work. Human beings are visually oriented. Being able to see and control a moving picture allows us to quickly and

Adaptive Behavior of Primary School Students with Visual Impairments: The Impact of Educational Settings

ERIC Educational Resources Information Center

Metsiou, Katerina; Papadopoulos, Konstantinos; Agaliotis, Ioannis

2011-01-01

This study explored the adaptive behavior of primary school students with visual impairments, as well as the impact of educational setting on their adaptive behavior. Instrumentation included an informal questionnaire and the Vineland Adaptive Behavior Scales. Participants were 36 primary school students with visual impairments. The educational…

When apperceptive agnosia is explained by a deficit of primary visual processing.

PubMed

Serino, Andrea; Cecere, Roberto; Dundon, Neil; Bertini, Caterina; Sanchez-Castaneda, Cristina; Làdavas, Elisabetta

2014-03-01

Visual agnosia is a deficit in shape perception, affecting figure, object, face and letter recognition. Agnosia is usually attributed to lesions to high-order modules of the visual system, which combine visual cues to represent the shape of objects. However, most of previously reported agnosia cases presented visual field (VF) defects and poor primary visual processing. The present case-study aims to verify whether form agnosia could be explained by a deficit in basic visual functions, rather that by a deficit in high-order shape recognition. Patient SDV suffered a bilateral lesion of the occipital cortex due to anoxia. When tested, he could navigate, interact with others, and was autonomous in daily life activities. However, he could not recognize objects from drawings and figures, read or recognize familiar faces. He was able to recognize objects by touch and people from their voice. Assessments of visual functions showed blindness at the centre of the VF, up to almost 5°, bilaterally, with better stimulus detection in the periphery. Colour and motion perception was preserved. Psychophysical experiments showed that SDV's visual recognition deficits were not explained by poor spatial acuity or by the crowding effect. Rather a severe deficit in line orientation processing might be a key mechanism explaining SDV's agnosia. Line orientation processing is a basic function of primary visual cortex neurons, necessary for detecting "edges" of visual stimuli to build up a "primal sketch" for object recognition. We propose, therefore, that some forms of visual agnosia may be explained by deficits in basic visual functions due to widespread lesions of the primary visual areas, affecting primary levels of visual processing. Copyright © 2013 Elsevier Ltd. All rights reserved.

Unlocking Proteomic Heterogeneity in Complex Diseases through Visual Analytics

PubMed Central

Bhavnani, Suresh K.; Dang, Bryant; Bellala, Gowtham; Divekar, Rohit; Visweswaran, Shyam; Brasier, Allan; Kurosky, Alex

2015-01-01

Despite years of preclinical development, biological interventions designed to treat complex diseases like asthma often fail in phase III clinical trials. These failures suggest that current methods to analyze biomedical data might be missing critical aspects of biological complexity such as the assumption that cases and controls come from homogeneous distributions. Here we discuss why and how methods from the rapidly evolving field of visual analytics can help translational teams (consisting of biologists, clinicians, and bioinformaticians) to address the challenge of modeling and inferring heterogeneity in the proteomic and phenotypic profiles of patients with complex diseases. Because a primary goal of visual analytics is to amplify the cognitive capacities of humans for detecting patterns in complex data, we begin with an overview of the cognitive foundations for the field of visual analytics. Next, we organize the primary ways in which a specific form of visual analytics called networks have been used to model and infer biological mechanisms, which help to identify the properties of networks that are particularly useful for the discovery and analysis of proteomic heterogeneity in complex diseases. We describe one such approach called subject-protein networks, and demonstrate its application on two proteomic datasets. This demonstration provides insights to help translational teams overcome theoretical, practical, and pedagogical hurdles for the widespread use of subject-protein networks for analyzing molecular heterogeneities, with the translational goal of designing biomarker-based clinical trials, and accelerating the development of personalized approaches to medicine. PMID:25684269

Asymmetrical Interhemispheric Connections Develop in Cat Visual Cortex after Early Unilateral Convergent Strabismus: Anatomy, Physiology, and Mechanisms

PubMed Central

Bui Quoc, Emmanuel; Ribot, Jérôme; Quenech’Du, Nicole; Doutremer, Suzette; Lebas, Nicolas; Grantyn, Alexej; Aushana, Yonane; Milleret, Chantal

2011-01-01

In the mammalian primary visual cortex, the corpus callosum contributes to the unification of the visual hemifields that project to the two hemispheres. Its development depends on visual experience. When this is abnormal, callosal connections must undergo dramatic anatomical and physiological changes. However, data concerning these changes are sparse and incomplete. Thus, little is known about the impact of abnormal postnatal visual experience on the development of callosal connections and their role in unifying representation of the two hemifields. Here, the effects of early unilateral convergent strabismus (a model of abnormal visual experience) were fully characterized with respect to the development of the callosal connections in cat visual cortex, an experimental model for humans. Electrophysiological responses and 3D reconstruction of single callosal axons show that abnormally asymmetrical callosal connections develop after unilateral convergent strabismus, resulting from an extension of axonal branches of specific orders in the hemisphere ipsilateral to the deviated eye and a decreased number of nodes and terminals in the other (ipsilateral to the non-deviated eye). Furthermore this asymmetrical organization prevents the establishment of a unifying representation of the two visual hemifields. As a general rule, we suggest that crossed and uncrossed retino-geniculo-cortical pathways contribute successively to the development of the callosal maps in visual cortex. PMID:22275883

Active training for amblyopia in adult rodents

PubMed Central

Sale, Alessandro; Berardi, Nicoletta

2015-01-01

Amblyopia is the most diffused form of visual function impairment affecting one eye, with a prevalence of 1–5% in the total world population. Amblyopia is usually caused by an early functional imbalance between the two eyes, deriving from anisometropia, strabismus, or congenital cataract, leading to severe deficits in visual acuity, contrast sensitivity and stereopsis. While amblyopia can be efficiently treated in children, it becomes irreversible in adults, as a result of a dramatic decline in visual cortex plasticity which occurs at the end of the critical period (CP) in the primary visual cortex. Notwithstanding this widely accepted dogma, recent evidence in animal models and in human patients have started to challenge this view, revealing a previously unsuspected possibility to enhance plasticity in the adult visual system and to achieve substantial visual function recovery. Among the new proposed intervention strategies, non invasive procedures based on environmental enrichment, physical exercise or visual perceptual learning (vPL) appear particularly promising in terms of future applicability in the clinical setting. In this survey, we will review recent literature concerning the application of these behavioral intervention strategies to the treatment of amblyopia, with a focus on possible underlying molecular and cellular mechanisms. PMID:26578911

Short Duration Bioastronautics Investigation 1904: Human Factors Assessment of Vibration Effects on Visual Performance during Launch

NASA Technical Reports Server (NTRS)

Thompson, Shelby; Holden, Kritina; Ebert, Douglas; Root, Phillip; Adelstein, Bernard; Jones, Jeffery

2009-01-01

The primary objective of the Short Duration Bioastronautics Investigation (SDBI) 1904 was to determine visual performance limits during Shuttle operational vibration and g-loads, specifically through the determination of minimal usable font sizes using Orion-type display formats. Currently there is little to no data available to quantify human visual performance under the extreme g- and vibration conditions of launch. Existing data on shuttle vibration magnitude and frequency is incomplete and does not address human visual performance. There have been anecdotal reports of performance decrements from shuttle crews, but no structured data have been collected. Previous work by NASA on the effects of vibration and linear g-loads on human performance was conducted during the Gemini era, but these experiments were performed using displays and controls that are dramatically different than current concepts being considered by the Constellation Program. Recently, three investigations of visual performance under vibration have been completed at NASA Ames Research Center: the first examining whole-body vibration, the second employing whole-body vibration coupled with a sustained g-load, and a third examining the effects of peak versus extended duration vibration. However, all of these studies were conducted using only a single x-axis direction (eyeballs in/out). Estimates of thrust oscillations from the Constellation Ares-I first stage are driving the need for realistic human performance requirements. SDBI 1904 was an opportunity to address the need for requirements by conducting a highly focused and applied evaluation in a relevant spaceflight environment. The SDBI was a companion effort to Detailed Test Objective (DTO) 695, which measured shuttle seat accelerations (vibration) during ascent. Data from the SDBI will serve an important role in interpreting the DTO vibration data. Both SDBI 1904 and DTO 695 were low impact with respect to flight resources, and combined, they represent an efficient and focused problem solving approach. This project provided (a) immediate data for developing preliminary human performance vibration requirements; (b) flight validated inputs for ongoing and future ground-based research; and (c) preliminary information related to Orion display format design.

Columnar Segregation of Magnocellular and Parvocellular Streams in Human Extrastriate Cortex

PubMed Central

2017-01-01

Magnocellular versus parvocellular (M-P) streams are fundamental to the organization of macaque visual cortex. Segregated, paired M-P streams extend from retina through LGN into V1. The M stream extends further into area V5/MT, and parts of V2. However, elsewhere in visual cortex, it remains unclear whether M-P-derived information (1) becomes intermixed or (2) remains segregated in M-P-dominated columns and neurons. Here we tested whether M-P streams exist in extrastriate cortical columns, in 8 human subjects (4 female). We acquired high-resolution fMRI at high field (7T), testing for M- and P-influenced columns within each of four cortical areas (V2, V3, V3A, and V4), based on known functional distinctions in M-P streams in macaque: (1) color versus luminance, (2) binocular disparity, (3) luminance contrast sensitivity, (4) peak spatial frequency, and (5) color/spatial interactions. Additional measurements of resting state activity (eyes closed) tested for segregated functional connections between these columns. We found M- and P-like functions and connections within and between segregated cortical columns in V2, V3, and (in most experiments) area V4. Area V3A was dominated by the M stream, without significant influence from the P stream. These results suggest that M-P streams exist, and extend through, specific columns in early/middle stages of human extrastriate cortex. SIGNIFICANCE STATEMENT The magnocellular and parvocellular (M-P) streams are fundamental components of primate visual cortical organization. These streams segregate both anatomical and functional properties in parallel, from retina through primary visual cortex. However, in most higher-order cortical sites, it is unknown whether such M-P streams exist and/or what form those streams would take. Moreover, it is unknown whether M-P streams exist in human cortex. Here, fMRI evidence measured at high field (7T) and high resolution revealed segregated M-P streams in four areas of human extrastriate cortex. These results suggest that M-P information is processed in segregated parallel channels throughout much of human visual cortex; the M-P streams are more than a convenient sorting property in earlier stages of the visual system. PMID:28724749

Consistency of the Proteome in Primary Human Keratinocytes With Respect to Gender, Age, and Skin Localization*

PubMed Central

Sprenger, Adrian; Weber, Sebastian; Zarai, Mostafa; Engelke, Rudolf; Nascimento, Juliana M.; Gretzmeier, Christine; Hilpert, Martin; Boerries, Melanie; Has, Cristina; Busch, Hauke; Bruckner-Tuderman, Leena; Dengjel, Jörn

2013-01-01

Keratinocytes account for 95% of all cells of the epidermis, the stratified squamous epithelium forming the outer layer of the skin, in which a significant number of skin diseases takes root. Immortalized keratinocyte cell lines are often used as research model systems providing standardized, reproducible, and homogenous biological material. Apart from that, primary human keratinocytes are frequently used for medical studies because the skin provides an important route for drug administration and is readily accessible for biopsies. However, comparability of these cell systems is not known. Cell lines may undergo phenotypic shifts and may differ from the in vivo situation in important aspects. Primary cells, on the other hand, may vary in biological functions depending on gender and age of the donor and localization of the biopsy specimen. Here we employed metabolic labeling in combination with quantitative mass spectrometry-based proteomics to assess A431 and HaCaT cell lines for their suitability as model systems. Compared with cell lines, comprehensive profiling of the primary human keratinocyte proteome with respect to gender, age, and skin localization identified an unexpected high proteomic consistency. The data were analyzed by an improved ontology enrichment analysis workflow designed for the study of global proteomics experiments. It enables a quick, comprehensive and unbiased overview of altered biological phenomena and links experimental data to literature. We guide through our workflow, point out its advantages compared with other methods and apply it to visualize differences of cell lines compared with primary human keratinocytes. PMID:23722187

Multi-modal information processing for visual workload relief

NASA Technical Reports Server (NTRS)

Burke, M. W.; Gilson, R. D.; Jagacinski, R. J.

1980-01-01

The simultaneous performance of two single-dimensional compensatory tracking tasks, one with the left hand and one with the right hand, is discussed. The tracking performed with the left hand was considered the primary task and was performed with a visual display or a quickened kinesthetic-tactual (KT) display. The right-handed tracking was considered the secondary task and was carried out only with a visual display. Although the two primary task displays had afforded equivalent performance in a critical tracking task performed alone, in the dual-task situation the quickened KT primary display resulted in superior secondary visual task performance. Comparisons of various combinations of primary and secondary visual displays in integrated or separated formats indicate that the superiority of the quickened KT display is not simply due to the elimination of visual scanning. Additional testing indicated that quickening per se also is not the immediate cause of the observed KT superiority.

Semantics of the visual environment encoded in parahippocampal cortex

PubMed Central

Bonner, Michael F.; Price, Amy Rose; Peelle, Jonathan E.; Grossman, Murray

2016-01-01

Semantic representations capture the statistics of experience and store this information in memory. A fundamental component of this memory system is knowledge of the visual environment, including knowledge of objects and their associations. Visual semantic information underlies a range of behaviors, from perceptual categorization to cognitive processes such as language and reasoning. Here we examine the neuroanatomic system that encodes visual semantics. Across three experiments, we found converging evidence indicating that knowledge of verbally mediated visual concepts relies on information encoded in a region of the ventral-medial temporal lobe centered on parahippocampal cortex. In an fMRI study, this region was strongly engaged by the processing of concepts relying on visual knowledge but not by concepts relying on other sensory modalities. In a study of patients with the semantic variant of primary progressive aphasia (semantic dementia), atrophy that encompassed this region was associated with a specific impairment in verbally mediated visual semantic knowledge. Finally, in a structural study of healthy adults from the fMRI experiment, gray matter density in this region related to individual variability in the processing of visual concepts. The anatomic location of these findings aligns with recent work linking the ventral-medial temporal lobe with high-level visual representation, contextual associations, and reasoning through imagination. Together this work suggests a critical role for parahippocampal cortex in linking the visual environment with knowledge systems in the human brain. PMID:26679216

Semantics of the Visual Environment Encoded in Parahippocampal Cortex.

PubMed

Bonner, Michael F; Price, Amy Rose; Peelle, Jonathan E; Grossman, Murray

2016-03-01

Semantic representations capture the statistics of experience and store this information in memory. A fundamental component of this memory system is knowledge of the visual environment, including knowledge of objects and their associations. Visual semantic information underlies a range of behaviors, from perceptual categorization to cognitive processes such as language and reasoning. Here we examine the neuroanatomic system that encodes visual semantics. Across three experiments, we found converging evidence indicating that knowledge of verbally mediated visual concepts relies on information encoded in a region of the ventral-medial temporal lobe centered on parahippocampal cortex. In an fMRI study, this region was strongly engaged by the processing of concepts relying on visual knowledge but not by concepts relying on other sensory modalities. In a study of patients with the semantic variant of primary progressive aphasia (semantic dementia), atrophy that encompassed this region was associated with a specific impairment in verbally mediated visual semantic knowledge. Finally, in a structural study of healthy adults from the fMRI experiment, gray matter density in this region related to individual variability in the processing of visual concepts. The anatomic location of these findings aligns with recent work linking the ventral-medial temporal lobe with high-level visual representation, contextual associations, and reasoning through imagination. Together, this work suggests a critical role for parahippocampal cortex in linking the visual environment with knowledge systems in the human brain.

Intracranial spectral amplitude dynamics of perceptual suppression in fronto-insular, occipito-temporal, and primary visual cortex

PubMed Central

Vidal, Juan R.; Perrone-Bertolotti, Marcela; Kahane, Philippe; Lachaux, Jean-Philippe

2015-01-01

If conscious perception requires global information integration across active distant brain networks, how does the loss of conscious perception affect neural processing in these distant networks? Pioneering studies on perceptual suppression (PS) described specific local neural network responses in primary visual cortex, thalamus and lateral prefrontal cortex of the macaque brain. Yet the neural effects of PS have rarely been studied with intracerebral recordings outside these cortices and simultaneously across distant brain areas. Here, we combined (1) a novel experimental paradigm in which we produced a similar perceptual disappearance and also re-appearance by using visual adaptation with transient contrast changes, with (2) electrophysiological observations from human intracranial electrodes sampling wide brain areas. We focused on broadband high-frequency (50–150 Hz, i.e., gamma) and low-frequency (8–24 Hz) neural activity amplitude modulations related to target visibility and invisibility. We report that low-frequency amplitude modulations reflected stimulus visibility in a larger ensemble of recording sites as compared to broadband gamma responses, across distinct brain regions including occipital, temporal and frontal cortices. Moreover, the dynamics of the broadband gamma response distinguished stimulus visibility from stimulus invisibility earlier in anterior insula and inferior frontal gyrus than in temporal regions, suggesting a possible role of fronto-insular cortices in top–down processing for conscious perception. Finally, we report that in primary visual cortex only low-frequency amplitude modulations correlated directly with perceptual status. Interestingly, in this sensory area broadband gamma was not modulated during PS but became positively modulated after 300 ms when stimuli were rendered visible again, suggesting that local networks could be ignited by top–down influences during conscious perception. PMID:25642199

Chromatic and Achromatic Spatial Resolution of Local Field Potentials in Awake Cortex

PubMed Central

Jansen, Michael; Li, Xiaobing; Lashgari, Reza; Kremkow, Jens; Bereshpolova, Yulia; Swadlow, Harvey A.; Zaidi, Qasim; Alonso, Jose-Manuel

2015-01-01

Local field potentials (LFPs) have become an important measure of neuronal population activity in the brain and could provide robust signals to guide the implant of visual cortical prosthesis in the future. However, it remains unclear whether LFPs can detect weak cortical responses (e.g., cortical responses to equiluminant color) and whether they have enough visual spatial resolution to distinguish different chromatic and achromatic stimulus patterns. By recording from awake behaving macaques in primary visual cortex, here we demonstrate that LFPs respond robustly to pure chromatic stimuli and exhibit ∼2.5 times lower spatial resolution for chromatic than achromatic stimulus patterns, a value that resembles the ratio of achromatic/chromatic resolution measured with psychophysical experiments in humans. We also show that, although the spatial resolution of LFP decays with visual eccentricity as is also the case for single neurons, LFPs have higher spatial resolution and show weaker response suppression to low spatial frequencies than spiking multiunit activity. These results indicate that LFP recordings are an excellent approach to measure spatial resolution from local populations of neurons in visual cortex including those responsive to color. PMID:25416722

Digital implementation of a neural network for imaging

NASA Astrophysics Data System (ADS)

Wood, Richard; McGlashan, Alex; Yatulis, Jay; Mascher, Peter; Bruce, Ian

2012-10-01

This paper outlines the design and testing of a digital imaging system that utilizes an artificial neural network with unsupervised and supervised learning to convert streaming input (real time) image space into parameter space. The primary objective of this work is to investigate the effectiveness of using a neural network to significantly reduce the information density of streaming images so that objects can be readily identified by a limited set of primary parameters and act as an enhanced human machine interface (HMI). Many applications are envisioned including use in biomedical imaging, anomaly detection and as an assistive device for the visually impaired. A digital circuit was designed and tested using a Field Programmable Gate Array (FPGA) and an off the shelf digital camera. Our results indicate that the networks can be readily trained when subject to limited sets of objects such as the alphabet. We can also separate limited object sets with rotational and positional invariance. The results also show that limited visual fields form with only local connectivity.

Cognitive Virtualization: Combining Cognitive Models and Virtual Environments

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

Tuan Q. Tran; David I. Gertman; Donald D. Dudenhoeffer

2007-08-01

3D manikins are often used in visualizations to model human activity in complex settings. Manikins assist in developing understanding of human actions, movements and routines in a variety of different environments representing new conceptual designs. One such environment is a nuclear power plant control room, here they have the potential to be used to simulate more precise ergonomic assessments of human work stations. Next generation control rooms will pose numerous challenges for system designers. The manikin modeling approach by itself, however, may be insufficient for dealing with the desired technical advancements and challenges of next generation automated systems. Uncertainty regardingmore » effective staffing levels; and the potential for negative human performance consequences in the presence of advanced automated systems (e.g., reduced vigilance, poor situation awareness, mistrust or blind faith in automation, higher information load and increased complexity) call for further research. Baseline assessment of novel control room equipment(s) and configurations needs to be conducted. These design uncertainties can be reduced through complementary analysis that merges ergonomic manikin models with models of higher cognitive functions, such as attention, memory, decision-making, and problem-solving. This paper will discuss recent advancements in merging a theoretical-driven cognitive modeling framework within a 3D visualization modeling tool to evaluate of next generation control room human factors and ergonomic assessment. Though this discussion primary focuses on control room design, the application for such a merger between 3D visualization and cognitive modeling can be extended to various areas of focus such as training and scenario planning.« less

Patterns of resting state connectivity in human primary visual cortical areas: a 7T fMRI study.

PubMed

Raemaekers, Mathijs; Schellekens, Wouter; van Wezel, Richard J A; Petridou, Natalia; Kristo, Gert; Ramsey, Nick F

2014-01-01

The nature and origin of fMRI resting state fluctuations and connectivity are still not fully known. More detailed knowledge on the relationship between resting state patterns and brain function may help to elucidate this matter. We therefore performed an in depth study of how resting state fluctuations map to the well known architecture of the visual system. We investigated resting state connectivity at both a fine and large scale within and across visual areas V1, V2 and V3 in ten human subjects using a 7Tesla scanner. We found evidence for several coexisting and overlapping connectivity structures at different spatial scales. At the fine-scale level we found enhanced connectivity between the same topographic locations in the fieldmaps of V1, V2 and V3, enhanced connectivity to the contralateral functional homologue, and to a lesser extent enhanced connectivity between iso-eccentric locations within the same visual area. However, by far the largest proportion of the resting state fluctuations occurred within large-scale bilateral networks. These large-scale networks mapped to some extent onto the architecture of the visual system and could thereby obscure fine-scale connectivity. In fact, most of the fine-scale connectivity only became apparent after the large-scale network fluctuations were filtered from the timeseries. We conclude that fMRI resting state fluctuations in the visual cortex may in fact be a composite signal of different overlapping sources. Isolating the different sources could enhance correlations between BOLD and electrophysiological correlates of resting state activity. © 2013 Elsevier Inc. All rights reserved.

Latent binocular function in amblyopia.

PubMed

Chadnova, Eva; Reynaud, Alexandre; Clavagnier, Simon; Hess, Robert F

2017-11-01

Recently, psychophysical studies have shown that humans with amblyopia do have binocular function that is not normally revealed due to dominant suppressive interactions under normal viewing conditions. Here we use magnetoencephalography (MEG) combined with dichoptic visual stimulation to investigate the underlying binocular function in humans with amblyopia for stimuli that, because of their temporal properties, would be expected to bypass suppressive effects and to reveal any underlying binocular function. We recorded contrast response functions in visual cortical area V1 of amblyopes and normal observers using a steady state visually evoked responses (SSVER) protocol. We used stimuli that were frequency-tagged at 4Hz and 6Hz that allowed identification of the responses from each eye and were of a sufficiently high temporal frequency (>3Hz) to bypass suppression. To characterize binocular function, we compared dichoptic masking between the two eyes in normal and amblyopic participants as well as interocular phase differences in the two groups. We observed that the primary visual cortex responds less to the stimulation of the amblyopic eye compared to the fellow eye. The pattern of interaction in the amblyopic visual system however was not significantly different between the amblyopic and fellow eyes. However, the amblyopic suppressive interactions were lower than those observed in the binocular system of our normal observers. Furthermore, we identified an interocular processing delay of approximately 20ms in our amblyopic group. To conclude, when suppression is greatly reduced, such as the case with our stimulation above 3Hz, the amblyopic visual system exhibits a lack of binocular interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cross-orientation suppression in human visual cortex

PubMed Central

Heeger, David J.

2011-01-01

Cross-orientation suppression was measured in human primary visual cortex (V1) to test the normalization model. Subjects viewed vertical target gratings (of varying contrasts) with or without a superimposed horizontal mask grating (fixed contrast). We used functional magnetic resonance imaging (fMRI) to measure the activity in each of several hypothetical channels (corresponding to subpopulations of neurons) with different orientation tunings and fit these orientation-selective responses with the normalization model. For the V1 channel maximally tuned to the target orientation, responses increased with target contrast but were suppressed when the horizontal mask was added, evident as a shift in the contrast gain of this channel's responses. For the channel maximally tuned to the mask orientation, a constant baseline response was evoked for all target contrasts when the mask was absent; responses decreased with increasing target contrast when the mask was present. The normalization model provided a good fit to the contrast-response functions with and without the mask. In a control experiment, the target and mask presentations were temporally interleaved, and we found no shift in contrast gain, i.e., no evidence for suppression. We conclude that the normalization model can explain cross-orientation suppression in human visual cortex. The approach adopted here can be applied broadly to infer, simultaneously, the responses of several subpopulations of neurons in the human brain that span particular stimulus or feature spaces, and characterize their interactions. In addition, it allows us to investigate how stimuli are represented by the inferred activity of entire neural populations. PMID:21775720

Multiple components of surround modulation in primary visual cortex: multiple neural circuits with multiple functions?

PubMed Central

Nurminen, Lauri; Angelucci, Alessandra

2014-01-01

The responses of neurons in primary visual cortex (V1) to stimulation of their receptive field (RF) are modulated by stimuli in the RF surround. This modulation is suppressive when the stimuli in the RF and surround are of similar orientation, but less suppressive or facilitatory when they are cross-oriented. Similarly, in human vision surround stimuli selectively suppress the perceived contrast of a central stimulus. Although the properties of surround modulation have been thoroughly characterized in many species, cortical areas and sensory modalities, its role in perception remains unknown. Here we argue that surround modulation in V1 consists of multiple components having different spatio-temporal and tuning properties, generated by different neural circuits and serving different visual functions. One component arises from LGN afferents, is fast, untuned for orientation, and spatially restricted to the surround region nearest to the RF (the near-surround); its function is to normalize V1 cell responses to local contrast. Intra-V1 horizontal connections contribute a slower, narrowly orientation-tuned component to near-surround modulation, whose function is to increase the coding efficiency of natural images in manner that leads to the extraction of object boundaries. The third component is generated by topdown feedback connections to V1, is fast, broadly orientation-tuned, and extends into the far-surround; its function is to enhance the salience of behaviorally relevant visual features. Far- and near-surround modulation, thus, act as parallel mechanisms: the former quickly detects and guides saccades/attention to salient visual scene locations, the latter segments object boundaries in the scene. PMID:25204770

The Brightness of Colour

PubMed Central

Corney, David; Haynes, John-Dylan; Rees, Geraint; Lotto, R. Beau

2009-01-01

Background The perception of brightness depends on spatial context: the same stimulus can appear light or dark depending on what surrounds it. A less well-known but equally important contextual phenomenon is that the colour of a stimulus can also alter its brightness. Specifically, stimuli that are more saturated (i.e. purer in colour) appear brighter than stimuli that are less saturated at the same luminance. Similarly, stimuli that are red or blue appear brighter than equiluminant yellow and green stimuli. This non-linear relationship between stimulus intensity and brightness, called the Helmholtz-Kohlrausch (HK) effect, was first described in the nineteenth century but has never been explained. Here, we take advantage of the relative simplicity of this ‘illusion’ to explain it and contextual effects more generally, by using a simple Bayesian ideal observer model of the human visual ecology. We also use fMRI brain scans to identify the neural correlates of brightness without changing the spatial context of the stimulus, which has complicated the interpretation of related fMRI studies. Results Rather than modelling human vision directly, we use a Bayesian ideal observer to model human visual ecology. We show that the HK effect is a result of encoding the non-linear statistical relationship between retinal images and natural scenes that would have been experienced by the human visual system in the past. We further show that the complexity of this relationship is due to the response functions of the cone photoreceptors, which themselves are thought to represent an efficient solution to encoding the statistics of images. Finally, we show that the locus of the response to the relationship between images and scenes lies in the primary visual cortex (V1), if not earlier in the visual system, since the brightness of colours (as opposed to their luminance) accords with activity in V1 as measured with fMRI. Conclusions The data suggest that perceptions of brightness represent a robust visual response to the likely sources of stimuli, as determined, in this instance, by the known statistical relationship between scenes and their retinal responses. While the responses of the early visual system (receptors in this case) may represent specifically the statistics of images, post receptor responses are more likely represent the statistical relationship between images and scenes. A corollary of this suggestion is that the visual cortex is adapted to relate the retinal image to behaviour given the statistics of its past interactions with the sources of retinal images: the visual cortex is adapted to the signals it receives from the eyes, and not directly to the world beyond. PMID:19333398

Visual short-term memory: activity supporting encoding and maintenance in retinotopic visual cortex.

PubMed

Sneve, Markus H; Alnæs, Dag; Endestad, Tor; Greenlee, Mark W; Magnussen, Svein

2012-10-15

Recent studies have demonstrated that retinotopic cortex maintains information about visual stimuli during retention intervals. However, the process by which transient stimulus-evoked sensory responses are transformed into enduring memory representations is unknown. Here, using fMRI and short-term visual memory tasks optimized for univariate and multivariate analysis approaches, we report differential involvement of human retinotopic areas during memory encoding of the low-level visual feature orientation. All visual areas show weaker responses when memory encoding processes are interrupted, possibly due to effects in orientation-sensitive primary visual cortex (V1) propagating across extrastriate areas. Furthermore, intermediate areas in both dorsal (V3a/b) and ventral (LO1/2) streams are significantly more active during memory encoding compared with non-memory (active and passive) processing of the same stimulus material. These effects in intermediate visual cortex are also observed during memory encoding of a different stimulus feature (spatial frequency), suggesting that these areas are involved in encoding processes on a higher level of representation. Using pattern-classification techniques to probe the representational content in visual cortex during delay periods, we further demonstrate that simply initiating memory encoding is not sufficient to produce long-lasting memory traces. Rather, active maintenance appears to underlie the observed memory-specific patterns of information in retinotopic cortex. Copyright © 2012 Elsevier Inc. All rights reserved.

Altered Functional Connectivity of the Primary Visual Cortex in Subjects with Amblyopia

PubMed Central

Ding, Kun; Liu, Yong; Yan, Xiaohe; Lin, Xiaoming; Jiang, Tianzi

2013-01-01

Amblyopia, which usually occurs during early childhood and results in poor or blurred vision, is a disorder of the visual system that is characterized by a deficiency in an otherwise physically normal eye or by a deficiency that is out of proportion with the structural or functional abnormalities of the eye. Our previous study demonstrated alterations in the spontaneous activity patterns of some brain regions in individuals with anisometropic amblyopia compared to subjects with normal vision. To date, it remains unknown whether patients with amblyopia show characteristic alterations in the functional connectivity patterns in the visual areas of the brain, particularly the primary visual area. In the present study, we investigated the differences in the functional connectivity of the primary visual area between individuals with amblyopia and normal-sighted subjects using resting functional magnetic resonance imaging. Our findings demonstrated that the cerebellum and the inferior parietal lobule showed altered functional connectivity with the primary visual area in individuals with amblyopia, and this finding provides further evidence for the disruption of the dorsal visual pathway in amblyopic subjects. PMID:23844297

Gravity Cues Embedded in the Kinematics of Human Motion Are Detected in Form-from-Motion Areas of the Visual System and in Motor-Related Areas

PubMed Central

Cignetti, Fabien; Chabeauti, Pierre-Yves; Menant, Jasmine; Anton, Jean-Luc J. J.; Schmitz, Christina; Vaugoyeau, Marianne; Assaiante, Christine

2017-01-01

The present study investigated the cortical areas engaged in the perception of graviceptive information embedded in biological motion (BM). To this end, functional magnetic resonance imaging was used to assess the cortical areas active during the observation of human movements performed under normogravity and microgravity (parabolic flight). Movements were defined by motion cues alone using point-light displays. We found that gravity modulated the activation of a restricted set of regions of the network subtending BM perception, including form-from-motion areas of the visual system (kinetic occipital region, lingual gyrus, cuneus) and motor-related areas (primary motor and somatosensory cortices). These findings suggest that compliance of observed movements with normal gravity was carried out by mapping them onto the observer’s motor system and by extracting their overall form from local motion of the moving light points. We propose that judgment on graviceptive information embedded in BM can be established based on motor resonance and visual familiarity mechanisms and not necessarily by accessing the internal model of gravitational motion stored in the vestibular cortex. PMID:28861024

The Brain Circuitry Underlying the Temporal Evolution of Nausea in Humans

PubMed Central

Sheehan, James D.; Kim, Jieun; LaCount, Lauren T.; Park, Kyungmo; Kaptchuk, Ted J.; Rosen, Bruce R.; Kuo, Braden

2013-01-01

Nausea is a universal human experience. It evolves slowly over time, and brain mechanisms underlying this evolution are not well understood. Our functional magnetic resonance imaging (fMRI) approach evaluated brain activity contributing to and arising from increasing motion sickness. Subjects rated transitions to increasing nausea, produced by visually induced vection within the fMRI environment. We evaluated parametrically increasing brain activity 1) precipitating increasing nausea and 2) following transition to stronger nausea. All subjects demonstrated visual stimulus–associated activation (P < 0.01) in primary and extrastriate visual cortices. In subjects experiencing motion sickness, increasing phasic activity preceding nausea was found in amygdala, putamen, and dorsal pons/locus ceruleus. Increasing sustained response following increased nausea was found in a broader network including insular, anterior cingulate, orbitofrontal, somatosensory and prefrontal cortices. Moreover, sustained anterior insula activation to strong nausea was correlated with midcingulate activation (r = 0.87), suggesting a closer linkage between these specific regions within the brain circuitry subserving nausea perception. Thus, while phasic activation in fear conditioning and noradrenergic brainstem regions precipitates transition to strong nausea, sustained activation following this transition occurs in a broader interoceptive, limbic, somatosensory, and cognitive network, reflecting the multiple dimensions of this aversive commonly occurring symptom. PMID:22473843

The brain circuitry underlying the temporal evolution of nausea in humans.

PubMed

Napadow, Vitaly; Sheehan, James D; Kim, Jieun; Lacount, Lauren T; Park, Kyungmo; Kaptchuk, Ted J; Rosen, Bruce R; Kuo, Braden

2013-04-01

Nausea is a universal human experience. It evolves slowly over time, and brain mechanisms underlying this evolution are not well understood. Our functional magnetic resonance imaging (fMRI) approach evaluated brain activity contributing to and arising from increasing motion sickness. Subjects rated transitions to increasing nausea, produced by visually induced vection within the fMRI environment. We evaluated parametrically increasing brain activity 1) precipitating increasing nausea and 2) following transition to stronger nausea. All subjects demonstrated visual stimulus-associated activation (P < 0.01) in primary and extrastriate visual cortices. In subjects experiencing motion sickness, increasing phasic activity preceding nausea was found in amygdala, putamen, and dorsal pons/locus ceruleus. Increasing sustained response following increased nausea was found in a broader network including insular, anterior cingulate, orbitofrontal, somatosensory and prefrontal cortices. Moreover, sustained anterior insula activation to strong nausea was correlated with midcingulate activation (r = 0.87), suggesting a closer linkage between these specific regions within the brain circuitry subserving nausea perception. Thus, while phasic activation in fear conditioning and noradrenergic brainstem regions precipitates transition to strong nausea, sustained activation following this transition occurs in a broader interoceptive, limbic, somatosensory, and cognitive network, reflecting the multiple dimensions of this aversive commonly occurring symptom.

A fully organic retinal prosthesis restores vision in a rat model of degenerative blindness

NASA Astrophysics Data System (ADS)

Maya-Vetencourt, José Fernando; Ghezzi, Diego; Antognazza, Maria Rosa; Colombo, Elisabetta; Mete, Maurizio; Feyen, Paul; Desii, Andrea; Buschiazzo, Ambra; di Paolo, Mattia; di Marco, Stefano; Ticconi, Flavia; Emionite, Laura; Shmal, Dmytro; Marini, Cecilia; Donelli, Ilaria; Freddi, Giuliano; Maccarone, Rita; Bisti, Silvia; Sambuceti, Gianmario; Pertile, Grazia; Lanzani, Guglielmo; Benfenati, Fabio

2017-06-01

The degeneration of photoreceptors in the retina is one of the major causes of adult blindness in humans. Unfortunately, no effective clinical treatments exist for the majority of retinal degenerative disorders. Here we report on the fabrication and functional validation of a fully organic prosthesis for long-term in vivo subretinal implantation in the eye of Royal College of Surgeons rats, a widely recognized model of retinitis pigmentosa. Electrophysiological and behavioural analyses reveal a prosthesis-dependent recovery of light sensitivity and visual acuity that persists up to 6-10 months after surgery. The rescue of the visual function is accompanied by an increase in the basal metabolic activity of the primary visual cortex, as demonstrated by positron emission tomography imaging. Our results highlight the possibility of developing a new generation of fully organic, highly biocompatible and functionally autonomous photovoltaic prostheses for subretinal implants to treat degenerative blindness.

Adaptation, perceptual learning, and plasticity of brain functions.

PubMed

Horton, Jonathan C; Fahle, Manfred; Mulder, Theo; Trauzettel-Klosinski, Susanne

2017-03-01

The capacity for functional restitution after brain damage is quite different in the sensory and motor systems. This series of presentations highlights the potential for adaptation, plasticity, and perceptual learning from an interdisciplinary perspective. The chances for restitution in the primary visual cortex are limited. Some patterns of visual field loss and recovery after stroke are common, whereas others are impossible, which can be explained by the arrangement and plasticity of the cortical map. On the other hand, compensatory mechanisms are effective, can occur spontaneously, and can be enhanced by training. In contrast to the human visual system, the motor system is highly flexible. This is based on special relationships between perception and action and between cognition and action. In addition, the healthy adult brain can learn new functions, e.g. increasing resolution above the retinal one. The significance of these studies for rehabilitation after brain damage will be discussed.

Beta oscillations define discrete perceptual cycles in the somatosensory domain.

PubMed

Baumgarten, Thomas J; Schnitzler, Alfons; Lange, Joachim

2015-09-29

Whether seeing a movie, listening to a song, or feeling a breeze on the skin, we coherently experience these stimuli as continuous, seamless percepts. However, there are rare perceptual phenomena that argue against continuous perception but, instead, suggest discrete processing of sensory input. Empirical evidence supporting such a discrete mechanism, however, remains scarce and comes entirely from the visual domain. Here, we demonstrate compelling evidence for discrete perceptual sampling in the somatosensory domain. Using magnetoencephalography (MEG) and a tactile temporal discrimination task in humans, we find that oscillatory alpha- and low beta-band (8-20 Hz) cycles in primary somatosensory cortex represent neurophysiological correlates of discrete perceptual cycles. Our results agree with several theoretical concepts of discrete perceptual sampling and empirical evidence of perceptual cycles in the visual domain. Critically, these results show that discrete perceptual cycles are not domain-specific, and thus restricted to the visual domain, but extend to the somatosensory domain.

A fully organic retinal prosthesis restores vision in a rat model of degenerative blindness

PubMed Central

Antognazza, Maria Rosa; Colombo, Elisabetta; Mete, Maurizio; Feyen, Paul; Desii, Andrea; Buschiazzo, Ambra; Di Paolo, Mattia; Di Marco, Stefano; Ticconi, Flavia; Emionite, Laura; Shmal, Dmytro; Marini, Cecilia; Donelli, Ilaria; Freddi, Giuliano; Maccarone, Rita; Bisti, Silvia; Sambuceti, Gianmario; Pertile, Grazia; Lanzani, Guglielmo; Benfenati, Fabio

2017-01-01

The degeneration of photoreceptors in the retina is one of the major causes of adult blindness in humans. Unfortunately, no effective clinical treatments exist for the majority of retinal degenerative disorders. Here we report on the fabrication and functional validation of a fully organic prosthesis for long-term in vivo subretinal implantation in the eye of Royal College of Surgeons rats, a widely recognized model of Retinitis pigmentosa. Electrophysiological and behavioral analyses reveal a prosthesis-dependent recovery of light-sensitivity and visual acuity that persists up to 6-10 months after surgery. The rescue of the visual function is accompanied by an increase in the basal metabolic activity of the primary visual cortex, as demonstrated by positron emission tomography imaging. Our results highlight the possibility of developing a new generation of fully organic, highly biocompatible and functionally autonomous photovoltaic prostheses for subretinal implants to treat degenerative blindness. PMID:28250420

PERSPECTIVE: Is acuity enough? Other considerations in clinical investigations of visual prostheses

NASA Astrophysics Data System (ADS)

Lepri, Bernard P.

2009-06-01

Visual impairing eye diseases are the major frontier facing ophthalmic research today in light of our rapidly aging population. The visual skills necessary for improving the quality of daily function and life are inextricably linked to these impairing diseases. Both research and reimbursement programs are emphasizing outcome-based results. Is improvement in visual acuity alone enough to improve the function and quality of life of visually impaired persons? This perspective summarizes the types of effectiveness endpoints for clinical investigations of visual prostheses that go beyond visual acuity. The clinical investigation of visual prostheses should include visual function, functional vision and quality of life measures. Specifically, they encompass contrast sensitivity, orientation and mobility, activities of daily living and quality of life assessments. The perspective focuses on the design of clinical trials for visual prostheses and the methods of determining effectiveness above and beyond visual acuity that will yield outcomes that are measured by improved function in the visual world and quality of life. The visually impaired population is the primary consideration in this presentation with particular emphases on retinitis pigmentosa and age-related macular degeneration. Clinical trials for visual prostheses cannot be isolated from the need for medical rehabilitation in order to obtain measurements of effectiveness that produce outcomes/evidence-based success. This approach will facilitate improvement in daily function and quality of life of patients with diseases that cause chronic vision impairment. The views and opinions are those of the author and do not necessarily reflect those of the US Food and Drug Administration, the US Department of Health and Human Services or the Public Health Service.

Gene expression profiles in anatomically and functionally distinct regions of the normal aged human brain

PubMed Central

Liang, Winnie S.; Dunckley, Travis; Beach, Thomas G.; Grover, Andrew; Mastroeni, Diego; Walker, Douglas G.; Caselli, Richard J.; Kukull, Walter A.; McKeel, Daniel; Morris, John C.; Hulette, Christine; Schmechel, Donald; Alexander, Gene E.; Reiman, Eric M.; Rogers, Joseph; Stephan, Dietrich A.

2008-01-01

In this article, we have characterized and compared gene expression profiles from laser capture microdissected neurons in six functionally and anatomically distinct regions from clinically and histopathologically normal aged human brains. These regions, which are also known to be differentially vulnerable to the histopathological and metabolic features of Alzheimer’s disease (AD), include the entorhinal cortex and hippocampus (limbic and paralimbic areas vulnerable to early neurofibrillary tangle pathology in AD), posterior cingulate cortex (a paralimbic area vulnerable to early metabolic abnormalities in AD), temporal and prefrontal cortex (unimodal and heteromodal sensory association areas vulnerable to early neuritic plaque pathology in AD), and primary visual cortex (a primary sensory area relatively spared in early AD). These neuronal profiles will provide valuable reference information for future studies of the brain, in normal aging, AD and other neurological and psychiatric disorders. PMID:17077275

Is orbital volume associated with eyeball and visual cortex volume in humans?

PubMed

Pearce, Eiluned; Bridge, Holly

2013-01-01

In humans orbital volume increases linearly with absolute latitude. Scaling across mammals between visual system components suggests that these larger orbits should translate into larger eyes and visual cortices in high latitude humans. Larger eyes at high latitudes may be required to maintain adequate visual acuity and enhance visual sensitivity under lower light levels. To test the assumption that orbital volume can accurately index eyeball and visual cortex volumes specifically in humans. Structural Magnetic Resonance Imaging (MRI) techniques are employed to measure eye and orbit (n = 88) and brain and visual cortex (n = 99) volumes in living humans. Facial dimensions and foramen magnum area (a proxy for body mass) were also measured. A significant positive linear relationship was found between (i) orbital and eyeball volumes, (ii) eyeball and visual cortex grey matter volumes and (iii) different visual cortical areas, independently of overall brain volume. In humans the components of the visual system scale from orbit to eye to visual cortex volume independently of overall brain size. These findings indicate that orbit volume can index eye and visual cortex volume in humans, suggesting that larger high latitude orbits do translate into larger visual cortices.

Is orbital volume associated with eyeball and visual cortex volume in humans?

PubMed Central

Pearce, Eiluned; Bridge, Holly

2013-01-01

Background In humans orbital volume increases linearly with absolute latitude. Scaling across mammals between visual system components suggests that these larger orbits should translate into larger eyes and visual cortices in high latitude humans. Larger eyes at high latitudes may be required to maintain adequate visual acuity and enhance visual sensitivity under lower light levels. Aim To test the assumption that orbital volume can accurately index eyeball and visual cortex volumes specifically in humans. Subjects & Methods Structural Magnetic Resonance Imaging (MRI) techniques are employed to measure eye and orbit (N=88), and brain and visual cortex (N=99) volumes in living humans. Facial dimensions and foramen magnum area (a proxy for body mass) were also measured. Results A significant positive linear relationship was found between (i) orbital and eyeball volumes, (ii) eyeball and visual cortex grey matter volumes, (iii) different visual cortical areas, independently of overall brain volume. Conclusion In humans the components of the visual system scale from orbit to eye to visual cortex volume independently of overall brain size. These findings indicate that orbit volume can index eye and visual cortex volume in humans, suggesting that larger high latitude orbits do translate into larger visual cortices. PMID:23879766

Secondary visual workload capability with primary visual and kinesthetic-tactual displays

NASA Technical Reports Server (NTRS)

Gilson, R. D.; Burke, M. W.; Jagacinski, R. J.

1978-01-01

Subjects performed a cross-adaptive tracking task with a visual secondary display and either a visual or a quickened kinesthetic-tactual (K-T) primary display. The quickened K-T display resulted in superior secondary task performance. Comparisons of secondary workload capability with integrated and separated visual displays indicated that the superiority of the quickened K-T display was not simply due to the elimination of visual scanning. When subjects did not have to perform a secondary task, there was no significant difference between visual and quickened K-T displays in performing a critical tracking task.

The sequence of cortical activity inferred by response latency variability in the human ventral pathway of face processing.

PubMed

Lin, Jo-Fu Lotus; Silva-Pereyra, Juan; Chou, Chih-Che; Lin, Fa-Hsuan

2018-04-11

Variability in neuronal response latency has been typically considered caused by random noise. Previous studies of single cells and large neuronal populations have shown that the temporal variability tends to increase along the visual pathway. Inspired by these previous studies, we hypothesized that functional areas at later stages in the visual pathway of face processing would have larger variability in the response latency. To test this hypothesis, we used magnetoencephalographic data collected when subjects were presented with images of human faces. Faces are known to elicit a sequence of activity from the primary visual cortex to the fusiform gyrus. Our results revealed that the fusiform gyrus showed larger variability in the response latency compared to the calcarine fissure. Dynamic and spectral analyses of the latency variability indicated that the response latency in the fusiform gyrus was more variable than in the calcarine fissure between 70 ms and 200 ms after the stimulus onset and between 4 Hz and 40 Hz, respectively. The sequential processing of face information from the calcarine sulcus to the fusiform sulcus was more reliably detected based on sizes of the response variability than instants of the maximal response peaks. With two areas in the ventral visual pathway, we show that the variability in response latency across brain areas can be used to infer the sequence of cortical activity.

Research on metallic material defect detection based on bionic sensing of human visual properties

NASA Astrophysics Data System (ADS)

Zhang, Pei Jiang; Cheng, Tao

2018-05-01

Due to the fact that human visual system can quickly lock the areas of interest in complex natural environment and focus on it, this paper proposes an eye-based visual attention mechanism by simulating human visual imaging features based on human visual attention mechanism Bionic Sensing Visual Inspection Model Method to Detect Defects of Metallic Materials in the Mechanical Field. First of all, according to the biologically visually significant low-level features, the mark of defect experience marking is used as the intermediate feature of simulated visual perception. Afterwards, SVM method was used to train the advanced features of visual defects of metal material. According to the weight of each party, the biometrics detection model of metal material defect, which simulates human visual characteristics, is obtained.

Frequency-Selective Attention in Auditory Scenes Recruits Frequency Representations Throughout Human Superior Temporal Cortex.

PubMed

Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

2017-05-01

A sound of interest may be tracked amid other salient sounds by focusing attention on its characteristic features including its frequency. Functional magnetic resonance imaging findings have indicated that frequency representations in human primary auditory cortex (AC) contribute to this feat. However, attentional modulations were examined at relatively low spatial and spectral resolutions, and frequency-selective contributions outside the primary AC could not be established. To address these issues, we compared blood oxygenation level-dependent (BOLD) responses in the superior temporal cortex of human listeners while they identified single frequencies versus listened selectively for various frequencies within a multifrequency scene. Using best-frequency mapping, we observed that the detailed spatial layout of attention-induced BOLD response enhancements in primary AC follows the tonotopy of stimulus-driven frequency representations-analogous to the "spotlight" of attention enhancing visuospatial representations in retinotopic visual cortex. Moreover, using an algorithm trained to discriminate stimulus-driven frequency representations, we could successfully decode the focus of frequency-selective attention from listeners' BOLD response patterns in nonprimary AC. Our results indicate that the human brain facilitates selective listening to a frequency of interest in a scene by reinforcing the fine-grained activity pattern throughout the entire superior temporal cortex that would be evoked if that frequency was present alone. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Horizontal tuning for faces originates in high-level Fusiform Face Area.

PubMed

Goffaux, Valerie; Duecker, Felix; Hausfeld, Lars; Schiltz, Christine; Goebel, Rainer

2016-01-29

Recent work indicates that the specialization of face visual perception relies on the privileged processing of horizontal angles of facial information. This suggests that stimulus properties assumed to be fully resolved in primary visual cortex (V1; e.g., orientation) in fact determine human vision until high-level stages of processing. To address this hypothesis, the present fMRI study explored the orientation sensitivity of V1 and high-level face-specialized ventral regions such as the Occipital Face Area (OFA) and Fusiform Face Area (FFA) to different angles of face information. Participants viewed face images filtered to retain information at horizontal, vertical or oblique angles. Filtered images were viewed upright, inverted and (phase-)scrambled. FFA responded most strongly to the horizontal range of upright face information; its activation pattern reliably separated horizontal from oblique ranges, but only when faces were upright. Moreover, activation patterns induced in the right FFA and the OFA by upright and inverted faces could only be separated based on horizontal information. This indicates that the specialized processing of upright face information in the OFA and FFA essentially relies on the encoding of horizontal facial cues. This pattern was not passively inherited from V1, which was found to respond less strongly to horizontal than other orientations likely due to adaptive whitening. Moreover, we found that orientation decoding accuracy in V1 was impaired for stimuli containing no meaningful shape. By showing that primary coding in V1 is influenced by high-order stimulus structure and that high-level processing is tuned to selective ranges of primary information, the present work suggests that primary and high-level levels of the visual system interact in order to modulate the processing of certain ranges of primary information depending on their relevance with respect to the stimulus and task at hand. Copyright © 2015 Elsevier Ltd. All rights reserved.

Causes and Prevention of Laparoscopic Bile Duct Injuries

PubMed Central

Way, Lawrence W.; Stewart, Lygia; Gantert, Walter; Liu, Kingsway; Lee, Crystine M.; Whang, Karen; Hunter, John G.

2003-01-01

Objective To apply human performance concepts in an attempt to understand the causes of and prevent laparoscopic bile duct injury. Summary Background Data Powerful conceptual advances have been made in understanding the nature and limits of human performance. Applying these findings in high-risk activities, such as commercial aviation, has allowed the work environment to be restructured to substantially reduce human error. Methods The authors analyzed 252 laparoscopic bile duct injuries according to the principles of the cognitive science of visual perception, judgment, and human error. The injury distribution was class I, 7%; class II, 22%; class III, 61%; and class IV, 10%. The data included operative radiographs, clinical records, and 22 videotapes of original operations. Results The primary cause of error in 97% of cases was a visual perceptual illusion. Faults in technical skill were present in only 3% of injuries. Knowledge and judgment errors were contributory but not primary. Sixty-four injuries (25%) were recognized at the index operation; the surgeon identified the problem early enough to limit the injury in only 15 (6%). In class III injuries the common duct, erroneously believed to be the cystic duct, was deliberately cut. This stemmed from an illusion of object form due to a specific uncommon configuration of the structures and the heuristic nature (unconscious assumptions) of human visual perception. The videotapes showed the persuasiveness of the illusion, and many operative reports described the operation as routine. Class II injuries resulted from a dissection too close to the common hepatic duct. Fundamentally an illusion, it was contributed to in some instances by working too deep in the triangle of Calot. Conclusions These data show that errors leading to laparoscopic bile duct injuries stem principally from misperception, not errors of skill, knowledge, or judgment. The misperception was so compelling that in most cases the surgeon did not recognize a problem. Even when irregularities were identified, corrective feedback did not occur, which is characteristic of human thinking under firmly held assumptions. These findings illustrate the complexity of human error in surgery while simultaneously providing insights. They demonstrate that automatically attributing technical complications to behavioral factors that rely on the assumption of control is likely to be wrong. Finally, this study shows that there are only a few points within laparoscopic cholecystectomy where the complication-causing errors occur, which suggests that focused training to heighten vigilance might be able to decrease the incidence of bile duct injury. PMID:12677139

Hunger-Dependent Enhancement of Food Cue Responses in Mouse Postrhinal Cortex and Lateral Amygdala.

PubMed

Burgess, Christian R; Ramesh, Rohan N; Sugden, Arthur U; Levandowski, Kirsten M; Minnig, Margaret A; Fenselau, Henning; Lowell, Bradford B; Andermann, Mark L

2016-09-07

The needs of the body can direct behavioral and neural processing toward motivationally relevant sensory cues. For example, human imaging studies have consistently found specific cortical areas with biased responses to food-associated visual cues in hungry subjects, but not in sated subjects. To obtain a cellular-level understanding of these hunger-dependent cortical response biases, we performed chronic two-photon calcium imaging in postrhinal association cortex (POR) and primary visual cortex (V1) of behaving mice. As in humans, neurons in mouse POR, but not V1, exhibited biases toward food-associated cues that were abolished by satiety. This emergent bias was mirrored by the innervation pattern of amygdalo-cortical feedback axons. Strikingly, these axons exhibited even stronger food cue biases and sensitivity to hunger state and trial history. These findings highlight a direct pathway by which the lateral amygdala may contribute to state-dependent cortical processing of motivationally relevant sensory cues. Published by Elsevier Inc.

Color in the Cortex—single- and double-opponent cells

PubMed Central

Shapley, Robert; Hawken, Michael

2011-01-01

This is a review of the research during the past 25 years on cortical processing of color signals. At the beginning of the period the modular view of cortical processing predominated. However, at present an alternative view, that color and form are linked inextricably in visual cortical processing, is more persuasive than it seemed in 1985. Also, the role of the primary visual cortex, V1, in color processing now seems much larger than it did in 1985. The re-evaluation of the important role of V1 in color vision was caused in part by investigations of human V1 responses to color, measured with functional magnetic resonance imaging, fMRI, and in part by the results of numerous studies of single-unit neurophysiology in non-human primates. The neurophysiological results have highlighted the importance of double-opponent cells in V1. Another new concept is population coding of hue, saturation, and brightness in cortical neuronal population activity. PMID:21333672

Visual dot interaction with short-term memory.

PubMed

Etindele Sosso, Faustin Armel

2017-06-01

Many neurodegenerative diseases have a memory component. Brain structures related to memory are affected by environmental stimuli, and it is difficult to dissociate effects of all behavior of neurons. Here, visual cortex of mice was stimulated with gratings and dot, and an observation of neuronal activity before and after was made. Bandwidth, firing rate and orientation selectivity index were evaluated. A primary communication between primary visual cortex and short-term memory appeared to show an interesting path to train cognitive circuitry and investigate the basics mechanisms of the neuronal learning. The findings also suggested the interplay between primary visual cortex and short-term plasticity. The properties inside a visual target shape the perception and affect the basic encoding. Using visual cortex, it may be possible to train the memory and improve the recovery of people with cognitive disabilities or memory deficit.

Seeing the world topsy-turvy: The primary role of kinematics in biological motion inversion effects.

PubMed

Fitzgerald, Sue-Anne; Brooks, Anna; van der Zwan, Rick; Blair, Duncan

2014-01-01

Physical inversion of whole or partial human body representations typically has catastrophic consequences on the observer's ability to perform visual processing tasks. Explanations usually focus on the effects of inversion on the visual system's ability to exploit configural or structural relationships, but more recently have also implicated motion or kinematic cue processing. Here, we systematically tested the role of both on perceptions of sex from upright and inverted point-light walkers. Our data suggest that inversion results in systematic degradations of the processing of kinematic cues. Specifically and intriguingly, they reveal sex-based kinematic differences: Kinematics characteristic of females generally are resistant to inversion effects, while those of males drive systematic sex misperceptions. Implications of the findings are discussed.

Seeing touch is correlated with content-specific activity in primary somatosensory cortex.

PubMed

Meyer, Kaspar; Kaplan, Jonas T; Essex, Ryan; Damasio, Hanna; Damasio, Antonio

2011-09-01

There is increasing evidence to suggest that primary sensory cortices can become active in the absence of external stimulation in their respective modalities. This occurs, for example, when stimuli processed via one sensory modality imply features characteristic of a different modality; for instance, visual stimuli that imply touch have been observed to activate the primary somatosensory cortex (SI). In the present study, we addressed the question of whether such cross-modal activations are content specific. To this end, we investigated neural activity in the primary somatosensory cortex of subjects who observed human hands engaged in the haptic exploration of different everyday objects. Using multivariate pattern analysis of functional magnetic resonance imaging data, we were able to predict, based exclusively on the activity pattern in SI, which of several objects a subject saw being explored. Along with previous studies that found similar evidence for other modalities, our results suggest that primary sensory cortices represent information relevant for their modality even when this information enters the brain via a different sensory system.

Hemifield columns co-opt ocular dominance column structure in human achiasma.

PubMed

Olman, Cheryl A; Bao, Pinglei; Engel, Stephen A; Grant, Andrea N; Purington, Chris; Qiu, Cheng; Schallmo, Michael-Paul; Tjan, Bosco S

2018-01-01

In the absence of an optic chiasm, visual input to the right eye is represented in primary visual cortex (V1) in the right hemisphere, while visual input to the left eye activates V1 in the left hemisphere. Retinotopic mapping In V1 reveals that in each hemisphere left and right visual hemifield representations are overlaid (Hoffmann et al., 2012). To explain how overlapping hemifield representations in V1 do not impair vision, we tested the hypothesis that visual projections from nasal and temporal retina create interdigitated left and right visual hemifield representations in V1, similar to the ocular dominance columns observed in neurotypical subjects (Victor et al., 2000). We used high-resolution fMRI at 7T to measure the spatial distribution of responses to left- and right-hemifield stimulation in one achiasmic subject. T 2 -weighted 2D Spin Echo images were acquired at 0.8mm isotropic resolution. The left eye was occluded. To the right eye, a presentation of flickering checkerboards alternated between the left and right visual fields in a blocked stimulus design. The participant performed a demanding orientation-discrimination task at fixation. A general linear model was used to estimate the preference of voxels in V1 to left- and right-hemifield stimulation. The spatial distribution of voxels with significant preference for each hemifield showed interdigitated clusters which densely packed V1 in the right hemisphere. The spatial distribution of hemifield-preference voxels in the achiasmic subject was stable between two days of testing and comparable in scale to that of human ocular dominance columns. These results are the first in vivo evidence showing that visual hemifield representations interdigitate in achiasmic V1 following a similar developmental course to that of ocular dominance columns in V1 with intact optic chiasm. Copyright © 2017 Elsevier Inc. All rights reserved.

Long-Term Visuo-Gustatory Appetitive and Aversive Conditioning Potentiate Human Visual Evoked Potentials

PubMed Central

Christoffersen, Gert R. J.; Laugesen, Jakob L.; Møller, Per; Bredie, Wender L. P.; Schachtman, Todd R.; Liljendahl, Christina; Viemose, Ida

2017-01-01

Human recognition of foods and beverages are often based on visual cues associated with flavors. The dynamics of neurophysiological plasticity related to acquisition of such long-term associations has only recently become the target of investigation. In the present work, the effects of appetitive and aversive visuo-gustatory conditioning were studied with high density EEG-recordings focusing on late components in the visual evoked potentials (VEPs), specifically the N2-P3 waves. Unfamiliar images were paired with either a pleasant or an unpleasant juice and VEPs evoked by the images were compared before and 1 day after the pairings. In electrodes located over posterior visual cortex areas, the following changes were observed after conditioning: the amplitude from the N2-peak to the P3-peak increased and the N2 peak delay was reduced. The percentage increase of N2-to-P3 amplitudes was asymmetrically distributed over the posterior hemispheres despite the fact that the images were bilaterally symmetrical across the two visual hemifields. The percentage increases of N2-to-P3 amplitudes in each experimental subject correlated with the subject’s evaluation of positive or negative hedonic valences of the two juices. The results from 118 scalp electrodes gave surface maps of theta power distributions showing increased power over posterior visual areas after the pairings. Source current distributions calculated from swLORETA revealed that visual evoked currents rose as a result of conditioning in five cortical regions—from primary visual areas and into the inferior temporal gyrus (ITG). These learning-induced changes were seen after both appetitive and aversive training while a sham trained control group showed no changes. It is concluded that long-term visuo-gustatory conditioning potentiated the N2-P3 complex, and it is suggested that the changes are regulated by the perceived hedonic valence of the US. PMID:28983243

Isolation and Characterization of Current Human Coronavirus Strains in Primary Human Epithelial Cell Cultures Reveal Differences in Target Cell Tropism

PubMed Central

Dijkman, Ronald; Jebbink, Maarten F.; Koekkoek, Sylvie M.; Deijs, Martin; Jónsdóttir, Hulda R.; Molenkamp, Richard; Ieven, Margareta; Goossens, Herman; Thiel, Volker

2013-01-01

The human airway epithelium (HAE) represents the entry port of many human respiratory viruses, including human coronaviruses (HCoVs). Nowadays, four HCoVs, HCoV-229E, HCoV-OC43, HCoV-HKU1, and HCoV-NL63, are known to be circulating worldwide, causing upper and lower respiratory tract infections in nonhospitalized and hospitalized children. Studies of the fundamental aspects of these HCoV infections at the primary entry port, such as cell tropism, are seriously hampered by the lack of a universal culture system or suitable animal models. To expand the knowledge on fundamental virus-host interactions for all four HCoVs at the site of primary infection, we used pseudostratified HAE cell cultures to isolate and characterize representative clinical HCoV strains directly from nasopharyngeal material. Ten contemporary isolates were obtained, representing HCoV-229E (n = 1), HCoV-NL63 (n = 1), HCoV-HKU1 (n = 4), and HCoV-OC43 (n = 4). For each strain, we analyzed the replication kinetics and progeny virus release on HAE cell cultures derived from different donors. Surprisingly, by visualizing HCoV infection by confocal microscopy, we observed that HCoV-229E employs a target cell tropism for nonciliated cells, whereas HCoV-OC43, HCoV-HKU1, and HCoV-NL63 all infect ciliated cells. Collectively, the data demonstrate that HAE cell cultures, which morphologically and functionally resemble human airways in vivo, represent a robust universal culture system for isolating and comparing all contemporary HCoV strains. PMID:23427150

Rapid Sequencing of Complete env Genes from Primary HIV-1 Samples.

PubMed

Laird Smith, Melissa; Murrell, Ben; Eren, Kemal; Ignacio, Caroline; Landais, Elise; Weaver, Steven; Phung, Pham; Ludka, Colleen; Hepler, Lance; Caballero, Gemma; Pollner, Tristan; Guo, Yan; Richman, Douglas; Poignard, Pascal; Paxinos, Ellen E; Kosakovsky Pond, Sergei L; Smith, Davey M

2016-07-01

The ability to study rapidly evolving viral populations has been constrained by the read length of next-generation sequencing approaches and the sampling depth of single-genome amplification methods. Here, we develop and characterize a method using Pacific Biosciences' Single Molecule, Real-Time (SMRT®) sequencing technology to sequence multiple, intact full-length human immunodeficiency virus-1 env genes amplified from viral RNA populations circulating in blood, and provide computational tools for analyzing and visualizing these data.

Development of Glutamatergic Proteins in Human Visual Cortex across the Lifespan.

PubMed

Siu, Caitlin R; Beshara, Simon P; Jones, David G; Murphy, Kathryn M

2017-06-21

Traditionally, human primary visual cortex (V1) has been thought to mature within the first few years of life, based on anatomical studies of synapse formation, and establishment of intracortical and intercortical connections. Human vision, however, develops well beyond the first few years. Previously, we found prolonged development of some GABAergic proteins in human V1 (Pinto et al., 2010). Yet as >80% of synapses in V1 are excitatory, it remains unanswered whether the majority of synapses regulating experience-dependent plasticity and receptive field properties develop late, like their inhibitory counterparts. To address this question, we used Western blotting of postmortem tissue from human V1 (12 female, 18 male) covering a range of ages. Then we quantified a set of postsynaptic glutamatergic proteins (PSD-95, GluA2, GluN1, GluN2A, GluN2B), calculated indices for functional pairs that are developmentally regulated (GluA2:GluN1; GluN2A:GluN2B), and determined interindividual variability. We found early loss of GluN1, prolonged development of PSD-95 and GluA2 into late childhood, protracted development of GluN2A until ∼40 years, and dramatic loss of GluN2A in aging. The GluA2:GluN1 index switched at ∼1 year, but the GluN2A:GluN2B index continued to shift until ∼40 year before changing back to GluN2B in aging. We also identified young childhood as a stage of heightened interindividual variability. The changes show that human V1 develops gradually through a series of five orchestrated stages, making it likely that V1 participates in visual development and plasticity across the lifespan. SIGNIFICANCE STATEMENT Anatomical structure of human V1 appears to mature early, but vision changes across the lifespan. This discrepancy has fostered two hypotheses: either other aspects of V1 continue changing, or later changes in visual perception depend on extrastriate areas. Previously, we showed that some GABAergic synaptic proteins change across the lifespan, but most synapses in V1 are excitatory leaving unanswered how they change. So we studied expression of glutamatergic proteins in human V1 to determine their development. Here we report prolonged maturation of glutamatergic proteins, with five stages that map onto life-long changes in human visual perception. Thus, the apparent discrepancy between development of structure and function may be explained by life-long synaptic changes in human V1. Copyright © 2017 the authors 0270-6474/17/376031-12$15.00/0.

Effects of light on brain and behavior

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

Brainard, G.C.

1994-12-31

It is obvious that light entering the eye permits the sensory capacity of vision. The human species is highly dependent on visual perception of the environment and consequently, the scientific study of vision and visual mechanisms is a centuries old endeavor. Relatively new discoveries are now leading to an expanded understanding of the role of light entering the eye - in addition to supporting vision, light has various nonvisual biological effects. Over the past thirty years, animal studies have shown that environmental light is the primary stimulus for regulating circadian rhythms, seasonal cycles, and neuroendocrine responses. As with all photobiologicalmore » phenomena, the wavelength, intensity, timing and duration of a light stimulus is important in determining its regulatory influence on the circadian and neuroendocrine systems. Initially, the effects of light on rhythms and hormones were observed only in sub-human species. Research over the past decade, however, has confirmed that light entering the eyes of humans is a potent stimulus for controlling physiological rhythms. The aim of this paper is to examine three specific nonvisual responses in humans which are mediated by light entering the eye: light-induced melatonin suppression, light therapy for winter depression, and enhancement of nighttime performance. This will serve as a brief introduction to the growing database which demonstrates how light stimuli can influence physiology, mood and behavior in humans. Such information greatly expands our understanding of the human eye and will ultimately change our use of light in the human environment.« less

Effects of light on brain and behavior

NASA Technical Reports Server (NTRS)

Brainard, George C.

1994-01-01

It is obvious that light entering the eye permits the sensory capacity of vision. The human species is highly dependent on visual perception of the environment and consequently, the scientific study of vision and visual mechanisms is a centuries old endeavor. Relatively new discoveries are now leading to an expanded understanding of the role of light entering the eye in addition to supporting vision, light has various nonvisual biological effects. Over the past thirty years, animal studies have shown that environmental light is the primary stimulus for regulating circadian rhythms, seasonal cycles, and neuroendocrine responses. As with all photobiological phenomena, the wavelength, intensity, timing and duration of a light stimulus is important in determining its regulatory influence on the circadian and neuroendocrine systems. Initially, the effects of light on rhythms and hormones were observed only in sub-human species. Research over the past decade, however, has confirmed that light entering the eyes of humans is a potent stimulus for controlling physiological rhythms. The aim of this paper is to examine three specific nonvisual responses in humans which are mediated by light entering the eye: light-induced melatonin suppression, light therapy for winter depression, and enhancement of nighttime performance. This will serve as a brief introduction to the growing database which demonstrates how light stimuli can influence physiology, mood and behavior in humans. Such information greatly expands our understanding of the human eye and will ultimately change our use of light in the human environment.

Neural connectivity of the lateral geniculate body in the human brain: diffusion tensor imaging study.

PubMed

Kwon, Hyeok Gyu; Jang, Sung Ho

2014-08-22

A few studies have reported on the neural connectivity of some neural structures of the visual system in the human brain. However, little is known about the neural connectivity of the lateral geniculate body (LGB). In the current study, using diffusion tensor tractography (DTT), we attempted to investigate the neural connectivity of the LGB in normal subjects. A total of 52 healthy subjects were recruited for this study. A seed region of interest was placed on the LGB using the FMRIB Software Library which is a probabilistic tractography method based on a multi-fiber model. Connectivity was defined as the incidence of connection between the LGB and target brain areas at the threshold of 5, 25, and 50 streamlines. In addition, connectivity represented the percentage of connection in all hemispheres of 52 subjects. We found the following characteristics of connectivity of the LGB at the threshold of 5 streamline: (1) high connectivity to the corpus callosum (91.3%) and the contralateral temporal cortex (56.7%) via the corpus callosum, (2) high connectivity to the ipsilateral cerebral cortex: the temporal lobe (100%), primary visual cortex (95.2%), and visual association cortex (77.9%). The LGB appeared to have high connectivity to the corpus callosum and both temporal cortexes as well as the ipsilateral occipital cortex. We believe that the results of this study would be helpful in investigation of the neural network associated with the visual system and brain plasticity of the visual system after brain injury. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Chromatic and Achromatic Spatial Resolution of Local Field Potentials in Awake Cortex.

PubMed

Jansen, Michael; Li, Xiaobing; Lashgari, Reza; Kremkow, Jens; Bereshpolova, Yulia; Swadlow, Harvey A; Zaidi, Qasim; Alonso, Jose-Manuel

2015-10-01

Local field potentials (LFPs) have become an important measure of neuronal population activity in the brain and could provide robust signals to guide the implant of visual cortical prosthesis in the future. However, it remains unclear whether LFPs can detect weak cortical responses (e.g., cortical responses to equiluminant color) and whether they have enough visual spatial resolution to distinguish different chromatic and achromatic stimulus patterns. By recording from awake behaving macaques in primary visual cortex, here we demonstrate that LFPs respond robustly to pure chromatic stimuli and exhibit ∼2.5 times lower spatial resolution for chromatic than achromatic stimulus patterns, a value that resembles the ratio of achromatic/chromatic resolution measured with psychophysical experiments in humans. We also show that, although the spatial resolution of LFP decays with visual eccentricity as is also the case for single neurons, LFPs have higher spatial resolution and show weaker response suppression to low spatial frequencies than spiking multiunit activity. These results indicate that LFP recordings are an excellent approach to measure spatial resolution from local populations of neurons in visual cortex including those responsive to color. © The Author 2014. Published by Oxford University Press.

Dependence of chromatic responses in V1 on visual field eccentricity and spatial frequency: an fMRI study.

PubMed

D'Souza, Dany V; Auer, Tibor; Frahm, Jens; Strasburger, Hans; Lee, Barry B

2016-03-01

Psychophysical sensitivity to red-green chromatic modulation decreases with visual eccentricity, compared to sensitivity to luminance modulation, even after appropriate stimulus scaling. This is likely to occur at a central, rather than a retinal, site. Blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) responses to stimuli designed to separately stimulate different afferent channels' [red-green, luminance, and short-wavelength (S)-cone] circular gratings were recorded as a function of visual eccentricity (±10  deg) and spatial frequency (SF) in human primary visual cortex (V1) and further visual areas (V2v, V3v). In V1, the SF tuning of BOLD fMRI responses became coarser with eccentricity. For red-green and luminance gratings, similar SF tuning curves were found at all eccentricities. The pattern for S-cone modulation differed, with SF tuning changing more slowly with eccentricity than for the other two modalities. This may be due to the different retinal distribution with eccentricity of this receptor type. A similar pattern held in V2v and V3v. This would suggest that transformation or spatial filtering of the chromatic (red-green) signal occurs beyond these areas.

Image understanding systems based on the unifying representation of perceptual and conceptual information and the solution of mid-level and high-level vision problems

NASA Astrophysics Data System (ADS)

Kuvychko, Igor

2001-10-01

Vision is a part of a larger information system that converts visual information into knowledge structures. These structures drive vision process, resolving ambiguity and uncertainty via feedback, and provide image understanding, that is an interpretation of visual information in terms of such knowledge models. A computer vision system based on such principles requires unifying representation of perceptual and conceptual information. Computer simulation models are built on the basis of graphs/networks. The ability of human brain to emulate similar graph/networks models is found. That means a very important shift of paradigm in our knowledge about brain from neural networks to the cortical software. Starting from the primary visual areas, brain analyzes an image as a graph-type spatial structure. Primary areas provide active fusion of image features on a spatial grid-like structure, where nodes are cortical columns. The spatial combination of different neighbor features cannot be described as a statistical/integral characteristic of the analyzed region, but uniquely characterizes such region itself. Spatial logic and topology naturally present in such structures. Mid-level vision processes like clustering, perceptual grouping, multilevel hierarchical compression, separation of figure from ground, etc. are special kinds of graph/network transformations. They convert low-level image structure into the set of more abstract ones, which represent objects and visual scene, making them easy for analysis by higher-level knowledge structures. Higher-level vision phenomena like shape from shading, occlusion, etc. are results of such analysis. Such approach gives opportunity not only to explain frequently unexplainable results of the cognitive science, but also to create intelligent computer vision systems that simulate perceptional processes in both what and where visual pathways. Such systems can open new horizons for robotic and computer vision industries.

Linking pain and the body: neural correlates of visually induced analgesia.

PubMed

Longo, Matthew R; Iannetti, Gian Domenico; Mancini, Flavia; Driver, Jon; Haggard, Patrick

2012-02-22

The visual context of seeing the body can reduce the experience of acute pain, producing a multisensory analgesia. Here we investigated the neural correlates of this "visually induced analgesia" using fMRI. We induced acute pain with an infrared laser while human participants looked either at their stimulated right hand or at another object. Behavioral results confirmed the expected analgesic effect of seeing the body, while fMRI results revealed an associated reduction of laser-induced activity in ipsilateral primary somatosensory cortex (SI) and contralateral operculoinsular cortex during the visual context of seeing the body. We further identified two known cortical networks activated by sensory stimulation: (1) a set of brain areas consistently activated by painful stimuli (the so-called "pain matrix"), and (2) an extensive set of posterior brain areas activated by the visual perception of the body ("visual body network"). Connectivity analyses via psychophysiological interactions revealed that the visual context of seeing the body increased effective connectivity (i.e., functional coupling) between posterior parietal nodes of the visual body network and the purported pain matrix. Increased connectivity with these posterior parietal nodes was seen for several pain-related regions, including somatosensory area SII, anterior and posterior insula, and anterior cingulate cortex. These findings suggest that visually induced analgesia does not involve an overall reduction of the cortical response elicited by laser stimulation, but is consequent to the interplay between the brain's pain network and a posterior network for body perception, resulting in modulation of the experience of pain.

Degraded attentional modulation of cortical neural populations in strabismic amblyopia

PubMed Central

Hou, Chuan; Kim, Yee-Joon; Lai, Xin Jie; Verghese, Preeti

2016-01-01

Behavioral studies have reported reduced spatial attention in amblyopia, a developmental disorder of spatial vision. However, the neural populations in the visual cortex linked with these behavioral spatial attention deficits have not been identified. Here, we use functional MRI–informed electroencephalography source imaging to measure the effect of attention on neural population activity in the visual cortex of human adult strabismic amblyopes who were stereoblind. We show that compared with controls, the modulatory effects of selective visual attention on the input from the amblyopic eye are substantially reduced in the primary visual cortex (V1) as well as in extrastriate visual areas hV4 and hMT+. Degraded attentional modulation is also found in the normal-acuity fellow eye in areas hV4 and hMT+ but not in V1. These results provide electrophysiological evidence that abnormal binocular input during a developmental critical period may impact cortical connections between the visual cortex and higher level cortices beyond the known amblyopic losses in V1 and V2, suggesting that a deficit of attentional modulation in the visual cortex is an important component of the functional impairment in amblyopia. Furthermore, we find that degraded attentional modulation in V1 is correlated with the magnitude of interocular suppression and the depth of amblyopia. These results support the view that the visual suppression often seen in strabismic amblyopia might be a form of attentional neglect of the visual input to the amblyopic eye. PMID:26885628

Degraded attentional modulation of cortical neural populations in strabismic amblyopia.

PubMed

Hou, Chuan; Kim, Yee-Joon; Lai, Xin Jie; Verghese, Preeti

2016-01-01

Behavioral studies have reported reduced spatial attention in amblyopia, a developmental disorder of spatial vision. However, the neural populations in the visual cortex linked with these behavioral spatial attention deficits have not been identified. Here, we use functional MRI-informed electroencephalography source imaging to measure the effect of attention on neural population activity in the visual cortex of human adult strabismic amblyopes who were stereoblind. We show that compared with controls, the modulatory effects of selective visual attention on the input from the amblyopic eye are substantially reduced in the primary visual cortex (V1) as well as in extrastriate visual areas hV4 and hMT+. Degraded attentional modulation is also found in the normal-acuity fellow eye in areas hV4 and hMT+ but not in V1. These results provide electrophysiological evidence that abnormal binocular input during a developmental critical period may impact cortical connections between the visual cortex and higher level cortices beyond the known amblyopic losses in V1 and V2, suggesting that a deficit of attentional modulation in the visual cortex is an important component of the functional impairment in amblyopia. Furthermore, we find that degraded attentional modulation in V1 is correlated with the magnitude of interocular suppression and the depth of amblyopia. These results support the view that the visual suppression often seen in strabismic amblyopia might be a form of attentional neglect of the visual input to the amblyopic eye.

The association between socioeconomic status and visual impairments among primary glaucoma: the results from Nationwide Korean National Health Insurance Cohort from 2004 to 2013.

PubMed

Sung, Haejune; Shin, Hyun Ho; Baek, Yunseng; Kim, Gyu Ah; Koh, Jae Sang; Park, Eun-Cheol; Shin, Jaeyong

2017-08-23

Glaucoma is one of the most leading causes of permanent visual impairments in Korea, and social expenses spent for the glaucoma are increasing. This study is to identify association between socioeconomic status and the visual impairments caused by primary glaucoma in Korea. This study is based on a cohort study using stratified representative samples in the National Health Insurance claim data from 2002 to 2013 with 1,025,340 representative subjects. Target subjects were patients who are newly diagnosed with primary glaucoma from 2004 to 2013. We conducted a multiple logistic regression analysis depending on the occurrence of visual impairment and its temporal order compared to the glaucoma diagnosis. Among 1728 patients with primary glaucoma, those with low and middle income shows higher odds ratio (OR) of the visual impairments than those with high income group (low income; OR = 3.42, 95% Confidential Interval (CI):2.06-5.66, middle income; OR = 2.13, 95% CI: 1.28-3.55), in case of the occurrence of the visual impairments preceded the diagnosis of glaucoma. Glaucoma patients without pre-existing glaucoma history before visual impairment have higher association between socioeconomic status and the occurrence of visual impairments by primary glaucoma. Since glaucoma had not been diagnosed and recognized yet, the differences may have been derived from the disparities of the awareness of the glaucoma. These findings call attention to the correlation between socioeconomic factors and the visual impairments by glaucoma, and raise public health needs over the importance of glaucoma awareness and eye screening for glaucoma, especially for low socioeconomic status.

The malleability of emotional perception: Short-term plasticity in retinotopic neurons accompanies the formation of perceptual biases to threat.

PubMed

Thigpen, Nina N; Bartsch, Felix; Keil, Andreas

2017-04-01

Emotional experience changes visual perception, leading to the prioritization of sensory information associated with threats and opportunities. These emotional biases have been extensively studied by basic and clinical scientists, but their underlying mechanism is not known. The present study combined measures of brain-electric activity and autonomic physiology to establish how threat biases emerge in human observers. Participants viewed stimuli designed to differentially challenge known properties of different neuronal populations along the visual pathway: location, eye, and orientation specificity. Biases were induced using aversive conditioning with only 1 combination of eye, orientation, and location predicting a noxious loud noise and replicated in a separate group of participants. Selective heart rate-orienting responses for the conditioned threat stimulus indicated bias formation. Retinotopic visual brain responses were persistently and selectively enhanced after massive aversive learning for only the threat stimulus and dissipated after extinction training. These changes were location-, eye-, and orientation-specific, supporting the hypothesis that short-term plasticity in primary visual neurons mediates the formation of perceptual biases to threat. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Cortical network differences in the sighted versus early blind for recognition of human-produced action sounds

PubMed Central

Lewis, James W.; Frum, Chris; Brefczynski-Lewis, Julie A.; Talkington, William J.; Walker, Nathan A.; Rapuano, Kristina M.; Kovach, Amanda L.

2012-01-01

Both sighted and blind individuals can readily interpret meaning behind everyday real-world sounds. In sighted listeners, we previously reported that regions along the bilateral posterior superior temporal sulci (pSTS) and middle temporal gyri (pMTG) are preferentially activated when presented with recognizable action sounds. These regions have generally been hypothesized to represent primary loci for complex motion processing, including visual biological motion processing and audio-visual integration. However, it remained unclear whether, or to what degree, life-long visual experience might impact functions related to hearing perception or memory of sound-source actions. Using functional magnetic resonance imaging (fMRI), we compared brain regions activated in congenitally blind versus sighted listeners in response to hearing a wide range of recognizable human-produced action sounds (excluding vocalizations) versus unrecognized, backward-played versions of those sounds. Here we show that recognized human action sounds commonly evoked activity in both groups along most of the left pSTS/pMTG complex, though with relatively greater activity in the right pSTS/pMTG by the blind group. These results indicate that portions of the postero-lateral temporal cortices contain domain-specific hubs for biological and/or complex motion processing independent of sensory-modality experience. Contrasting the two groups, the sighted listeners preferentially activated bilateral parietal plus medial and lateral frontal networks, while the blind listeners preferentially activated left anterior insula plus bilateral anterior calcarine and medial occipital regions, including what would otherwise have been visual-related cortex. These global-level network differences suggest that blind and sighted listeners may preferentially use different memory retrieval strategies when attempting to recognize action sounds. PMID:21305666

Link between orientation and retinotopic maps in primary visual cortex

PubMed Central

Paik, Se-Bum; Ringach, Dario L.

2012-01-01

Maps representing the preference of neurons for the location and orientation of a stimulus on the visual field are a hallmark of primary visual cortex. It is not yet known how these maps develop and what function they play in visual processing. One hypothesis postulates that orientation maps are initially seeded by the spatial interference of ON- and OFF-center retinal receptive field mosaics. Here we show that such a mechanism predicts a link between the layout of orientation preferences around singularities of different signs and the cardinal axes of the retinotopic map. Moreover, we confirm the predicted relationship holds in tree shrew primary visual cortex. These findings provide additional support for the notion that spatially structured input from the retina may provide a blueprint for the early development of cortical maps and receptive fields. More broadly, it raises the possibility that spatially structured input from the periphery may shape the organization of primary sensory cortex of other modalities as well. PMID:22509015

Task-dependent engagements of the primary visual cortex during kinesthetic and visual motor imagery.

PubMed

Mizuguchi, Nobuaki; Nakamura, Maiko; Kanosue, Kazuyuki

2017-01-01

Motor imagery can be divided into kinesthetic and visual aspects. In the present study, we investigated excitability in the corticospinal tract and primary visual cortex (V1) during kinesthetic and visual motor imagery. To accomplish this, we measured motor evoked potentials (MEPs) and probability of phosphene occurrence during the two types of motor imageries of finger tapping. The MEPs and phosphenes were induced by transcranial magnetic stimulation to the primary motor cortex and V1, respectively. The amplitudes of MEPs and probability of phosphene occurrence during motor imagery were normalized based on the values obtained at rest. Corticospinal excitability increased during both kinesthetic and visual motor imagery, while excitability in V1 was increased only during visual motor imagery. These results imply that modulation of cortical excitability during kinesthetic and visual motor imagery is task dependent. The present finding aids in the understanding of the neural mechanisms underlying motor imagery and provides useful information for the use of motor imagery in rehabilitation or motor imagery training. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dynamics of coherent flow structures of a pulsating unsteady glottal jet in human phonation.

NASA Astrophysics Data System (ADS)

Neubauer, Juergen; Miraghaie, Reza; Berry, David

2004-11-01

The primary sound source for human voice is oscillation of the vocal folds in the larynx. Phonation is the self-sustained oscillation of the viscoelastic vocal fold tissue driven by the air flow from the lung. It is due to the flow-induced Hopf instability of the biomechanical-aerodynamic system of vocal folds coupled to the aeroacoustic driving air flow. The aim of this study is to provide insight to the aero-acoustic part of the primary sound source of human voice. A physical rubber model of vocal folds with air flow conditions typical for human phonation was used. This model exhibits self-sustained oscillations similar to those in human phonation. The oscillating physical model can be regarded as a dynamic slit-like orifice that discharges a pulsating unsteady jet. A left-right flapping of the glottal jet axis was detected using hotwire anemometer measurements of the unsteady glottal jet. Flow visualization experiments revealed the detachment of the glottal jet from the physical model folds during the accelerating and decelerating phase of the jet pulsation. Roll-up of large-scale vortex rings as well as secondary vortex shedding in the form of Von Karman street due to shear layer instability were found downstream of the physical model.

Nonlinear dynamics of cortical responses to color in the human cVEP.

PubMed

Nunez, Valerie; Shapley, Robert M; Gordon, James

2017-09-01

The main finding of this paper is that the human visual cortex responds in a very nonlinear manner to the color contrast of pure color patterns. We examined human cortical responses to color checkerboard patterns at many color contrasts, measuring the chromatic visual evoked potential (cVEP) with a dense electrode array. Cortical topography of the cVEPs showed that they were localized near the posterior electrode at position Oz, indicating that the primary cortex (V1) was the major source of responses. The choice of fine spatial patterns as stimuli caused the cVEP response to be driven by double-opponent neurons in V1. The cVEP waveform revealed nonlinear color signal processing in the V1 cortex. The cVEP time-to-peak decreased and the waveform's shape was markedly narrower with increasing cone contrast. Comparison of the linear dynamics of retinal and lateral geniculate nucleus responses with the nonlinear dynamics of the cortical cVEP indicated that the nonlinear dynamics originated in the V1 cortex. The nature of the nonlinearity is a kind of automatic gain control that adjusts cortical dynamics to be faster when color contrast is greater.

Electrophysiological recordings in humans reveal reduced location-specific attentional-shift activity prior to recentering saccades

PubMed Central

Boehler, C. Nicolas; Zhang, Helen H.; Schoenfeld, Mircea A.; Woldorff, Marty G.

2012-01-01

Being able to effectively explore the visual world is of fundamental importance, and it has been suggested that the straight-ahead gaze position within the egocentric reference frame (“primary position”) might play a special role in this context. In the present study we employed human electroencephalography (EEG) to examine neural activity related to the spatial guidance of saccadic eye movements. Moreover, we sought to investigate whether such activity would be modulated by the spatial relation of saccade direction to the primary gaze position (recentering saccades). Participants executed endogenously cued saccades between five equidistant locations along the horizontal meridian. This design allowed for the comparison of isoamplitude saccades from the same starting position that were oriented either toward the primary position (centripetal) or further away from it (centrifugal). By back-averaging time-locked to the saccade onset on each trial, we identified a parietally distributed, negative-polarity EEG deflection contralateral to the direction of the upcoming saccade. Importantly, this contralateral presaccadic negativity, which appeared to reflect the location-specific attentional guidance of the eye movement, was attenuated for recentering saccades relative to isoamplitude centrifugal saccades. This differential electrophysiological signature was paralleled by faster saccadic reaction times and was substantially more apparent when time-locking the data to the onset of the saccade rather than to the onset of the cue, suggesting a tight temporal association with saccade initiation. The diminished level of this presaccadic component for recentering saccades may reflect the preferential coding of the straight-ahead gaze position, in which both the eye-centered and head-centered reference frames are perfectly aligned and from which the visual world can be effectively explored. PMID:22157127

Neurophysiology and Neuroanatomy of Reflexive and Volitional Saccades: Evidence from Studies of Humans

PubMed Central

McDowell, Jennifer E.; Dyckman, Kara A.; Austin, Benjamin; Clementz, Brett A.

2008-01-01

This review provides a summary of the contributions made by human functional neuroimaging studies to the understanding of neural correlates of saccadic control. The generation of simple visually-guided saccades (redirections of gaze to a visual stimulus or prosaccades) and more complex volitional saccades require similar basic neural circuitry with additional neural regions supporting requisite higher level processes. The saccadic system has been studied extensively in non-human primates (e.g. single unit recordings) and humans (e.g. lesions and neuroimaging). Considerable knowledge of this system’s functional neuroanatomy makes it useful for investigating models of cognitive control. The network involved in prosaccade generation (by definition exogenously-driven) includes subcortical (striatum, thalamus, superior colliculus, and cerebellar vermis) and cortical structures (primary visual, extrastriate, and parietal cortices, and frontal and supplementary eye fields). Activation in these regions is also observed during endogenously-driven voluntary saccades (e.g. antisaccades, ocular motor delayed response or memory saccades, predictive tracking tasks and anticipatory saccades, and saccade sequencing), all of which require complex cognitive processes like inhibition and working memory. These additional requirements are supported by changes in neural activity in basic saccade circuitry and by recruitment of additional neural regions (such as prefrontal and anterior cingulate cortices). Activity in visual cortex is modulated as a function of task demands and may predict the type of saccade to be generated, perhaps via top-down control mechanisms. Neuroimaging studies suggest two foci of activation within FEF - medial and lateral - which may correspond to volitional and reflexive demands, respectively. Future research on saccade control could usefully (i) delineate important anatomical subdivisions that underlie functional differences, (ii) evaluate functional connectivity of anatomical regions supporting saccade generation using methods such as ICA and structural equation modeling, (iii) investigate how context affects behavior and brain activity, and (iv) use multi-modal neuroimaging to maximize spatial and temporal resolution. PMID:18835656

Coarse-Scale Biases for Spirals and Orientation in Human Visual Cortex

PubMed Central

Heeger, David J.

2013-01-01

Multivariate decoding analyses are widely applied to functional magnetic resonance imaging (fMRI) data, but there is controversy over their interpretation. Orientation decoding in primary visual cortex (V1) reflects coarse-scale biases, including an over-representation of radial orientations. But fMRI responses to clockwise and counter-clockwise spirals can also be decoded. Because these stimuli are matched for radial orientation, while differing in local orientation, it has been argued that fine-scale columnar selectivity for orientation contributes to orientation decoding. We measured fMRI responses in human V1 to both oriented gratings and spirals. Responses to oriented gratings exhibited a complex topography, including a radial bias that was most pronounced in the peripheral representation, and a near-vertical bias that was most pronounced near the foveal representation. Responses to clockwise and counter-clockwise spirals also exhibited coarse-scale organization, at the scale of entire visual quadrants. The preference of each voxel for clockwise or counter-clockwise spirals was predicted from the preferences of that voxel for orientation and spatial position (i.e., within the retinotopic map). Our results demonstrate a bias for local stimulus orientation that has a coarse spatial scale, is robust across stimulus classes (spirals and gratings), and suffices to explain decoding from fMRI responses in V1. PMID:24336733

Splenium of Corpus Callosum: Patterns of Interhemispheric Interaction in Children and Adults

PubMed Central

Knyazeva, Maria G.

2013-01-01

The splenium of the corpus callosum connects the posterior cortices with fibers varying in size from thin late-myelinating axons in the anterior part, predominantly connecting parietal and temporal areas, to thick early-myelinating fibers in the posterior part, linking primary and secondary visual areas. In the adult human brain, the function of the splenium in a given area is defined by the specialization of the area and implemented via excitation and/or suppression of the contralateral homotopic and heterotopic areas at the same or different level of visual hierarchy. These mechanisms are facilitated by interhemispheric synchronization of oscillatory activity, also supported by the splenium. In postnatal ontogenesis, structural MRI reveals a protracted formation of the splenium during the first two decades of human life. In doing so, the slow myelination of the splenium correlates with the formation of interhemispheric excitatory influences in the extrastriate areas and the EEG synchronization, while the gradual increase of inhibitory effects in the striate cortex is linked to the local inhibitory circuitry. Reshaping interactions between interhemispherically distributed networks under various perceptual contexts allows sparsification of responses to superfluous information from the visual environment, leading to a reduction of metabolic and structural redundancy in a child's brain. PMID:23577273

Products of cells from gliomas: VIII. Multiple-well immunoperoxidase assay of immunoreactivity of primary hybridoma supernatants with human glioma and brain tissue and cultured glioma cells.

PubMed

McKeever, P E; Wahl, R L; Shakui, P; Jackson, G A; Letica, L H; Liebert, M; Taren, J A; Beierwaltes, W H; Hoff, J T

1990-06-01

To test the feasibility of primary screening of hybridoma supernatants against human glioma tissue, over 5000 combinations of hybridoma supernatants with glioma tissue, cultured glioma cells, and normal central neural tissue were screened with a new multiple-well (M-well) screening system. This is an immunoperoxidase assay system with visual endpoints for screening 20-30 hybridoma supernatants per single microscope slide. There were extensive differences between specificities to tissue and to cultured glioma cells when both were screened with M-wells and when cultured cells were screened with standard semi-automated fluorescence. Primary M-well screening with glioma tissue detected seven hybridoma supernatants that specifically identified parenchymal cells of glioma tissue and that were not detected with cultured cells. Immunoreactivities of individual supernatants for vascular components (nine supernatants), necrosis (five supernatants), and nuclei (three supernatants) were detected. Other supernatants bound multiple sites on glioma tissue and/or subpopulations of neurons and glia of normal tissue. The results show that primary screening with glioma tissue detects a number of different specificities of hybridoma supernatants to gliomas not detected by conventional screening with cultured cells. These are potentially applicable to diagnosis and therapy.

Rapid Sequencing of Complete env Genes from Primary HIV-1 Samples

PubMed Central

Eren, Kemal; Ignacio, Caroline; Landais, Elise; Weaver, Steven; Phung, Pham; Ludka, Colleen; Hepler, Lance; Caballero, Gemma; Pollner, Tristan; Guo, Yan; Richman, Douglas; Poignard, Pascal; Paxinos, Ellen E.; Kosakovsky Pond, Sergei L.

2016-01-01

Abstract The ability to study rapidly evolving viral populations has been constrained by the read length of next-generation sequencing approaches and the sampling depth of single-genome amplification methods. Here, we develop and characterize a method using Pacific Biosciences’ Single Molecule, Real-Time (SMRT®) sequencing technology to sequence multiple, intact full-length human immunodeficiency virus-1 env genes amplified from viral RNA populations circulating in blood, and provide computational tools for analyzing and visualizing these data. PMID:29492273

Structural and functional correlates of visual field asymmetry in the human brain by diffusion kurtosis MRI and functional MRI.

PubMed

O'Connell, Caitlin; Ho, Leon C; Murphy, Matthew C; Conner, Ian P; Wollstein, Gadi; Cham, Rakie; Chan, Kevin C

2016-11-09

Human visual performance has been observed to show superiority in localized regions of the visual field across many classes of stimuli. However, the underlying neural mechanisms remain unclear. This study aims to determine whether the visual information processing in the human brain is dependent on the location of stimuli in the visual field and the corresponding neuroarchitecture using blood-oxygenation-level-dependent functional MRI (fMRI) and diffusion kurtosis MRI, respectively, in 15 healthy individuals at 3 T. In fMRI, visual stimulation to the lower hemifield showed stronger brain responses and larger brain activation volumes than the upper hemifield, indicative of the differential sensitivity of the human brain across the visual field. In diffusion kurtosis MRI, the brain regions mapping to the lower visual field showed higher mean kurtosis, but not fractional anisotropy or mean diffusivity compared with the upper visual field. These results suggested the different distributions of microstructural organization across visual field brain representations. There was also a strong positive relationship between diffusion kurtosis and fMRI responses in the lower field brain representations. In summary, this study suggested the structural and functional brain involvements in the asymmetry of visual field responses in humans, and is important to the neurophysiological and psychological understanding of human visual information processing.

Contextual modulation of primary visual cortex by auditory signals.

PubMed

Petro, L S; Paton, A T; Muckli, L

2017-02-19

Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195-201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256-1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame.This article is part of the themed issue 'Auditory and visual scene analysis'. © 2017 The Authors.

Contextual modulation of primary visual cortex by auditory signals

PubMed Central

Paton, A. T.

2017-01-01

Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195–201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256–1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame. This article is part of the themed issue ‘Auditory and visual scene analysis’. PMID:28044015

Dissociation between Neural Signatures of Stimulus and Choice in Population Activity of Human V1 during Perceptual Decision-Making

PubMed Central

Choe, Kyoung Whan; Blake, Randolph

2014-01-01

Primary visual cortex (V1) forms the initial cortical representation of objects and events in our visual environment, and it distributes information about that representation to higher cortical areas within the visual hierarchy. Decades of work have established tight linkages between neural activity occurring in V1 and features comprising the retinal image, but it remains debatable how that activity relates to perceptual decisions. An actively debated question is the extent to which V1 responses determine, on a trial-by-trial basis, perceptual choices made by observers. By inspecting the population activity of V1 from human observers engaged in a difficult visual discrimination task, we tested one essential prediction of the deterministic view: choice-related activity, if it exists in V1, and stimulus-related activity should occur in the same neural ensemble of neurons at the same time. Our findings do not support this prediction: while cortical activity signifying the variability in choice behavior was indeed found in V1, that activity was dissociated from activity representing stimulus differences relevant to the task, being advanced in time and carried by a different neural ensemble. The spatiotemporal dynamics of population responses suggest that short-term priors, perhaps formed in higher cortical areas involved in perceptual inference, act to modulate V1 activity prior to stimulus onset without modifying subsequent activity that actually represents stimulus features within V1. PMID:24523561

[Magnetotherapy designed to affect cervical sympathetic ganglia for the treatment of patients with primary open-angle glaucoma].

PubMed

Veselova, E V; Kamenskikh, T G; Raĭgorodkiĭ, Iu M; Kolbenev, I O; Myshkina, E S

2010-01-01

The traveling magnetic field was used to treat primary open-angle glaucoma. The field was applied to the projection of cervical sympathetic ganglia of the patients. Hemodynamic parameters of posterior short ciliary arteries and central retinal artery were analysed along with visual evoked potentials, visual field limits, and visual acuity. It was shown that magnetotherapy with the use of an AMO-ATOS apparatus produces better clinical results in patients with stage I and II primary open-angle glaucoma compared with medicamentous therapy (intake of trental tablets).

Distribution of neurons in functional areas of the mouse cerebral cortex reveals quantitatively different cortical zones

PubMed Central

Herculano-Houzel, Suzana; Watson, Charles; Paxinos, George

2013-01-01

How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005) to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find that the number of neurons underneath a surface area (the N/A ratio) varies 4.5-fold across functional areas and neuronal density varies 3.2-fold. The face area of S1 contains the most neurons, followed by motor cortex and the primary visual cortex. Remarkably, while the distribution of neurons across functional areas does not accompany the distribution of surface area, it mirrors closely the distribution of cortical volumes—with the exception of the visual areas, which hold more neurons than expected for their volume. Across the non-visual cortex, the volume of individual functional areas is a shared linear function of their number of neurons, while in the visual areas, neuronal densities are much higher than in all other areas. In contrast, the 18 functional areas cluster into three different zones according to the relationship between the N/A ratio and cortical thickness and neuronal density: these three clusters can be called visual, sensory, and, possibly, associative. These findings are remarkably similar to those in the human cerebral cortex (Ribeiro et al., 2013) and suggest that, like the human cerebral cortex, the mouse cerebral cortex comprises two zones that differ in how neurons form the cortical volume, and three zones that differ in how neurons are distributed underneath the cortical surface, possibly in relation to local differences in connectivity through the white matter. Our results suggest that beyond the developmental divide into visual and non-visual cortex, functional areas initially share a common distribution of neurons along the parenchyma that become delimited into functional areas according to the pattern of connectivity established later. PMID:24155697

Motion perception: behavior and neural substrate.

PubMed

Mather, George

2011-05-01

Visual motion perception is vital for survival. Single-unit recordings in primate primary visual cortex (V1) have revealed the existence of specialized motion sensing neurons; perceptual effects such as the motion after-effect demonstrate their importance for motion perception. Human psychophysical data on motion detection can be explained by a computational model of cortical motion sensors. Both psychophysical and physiological data reveal at least two classes of motion sensor capable of sensing motion in luminance-defined and texture-defined patterns, respectively. Psychophysical experiments also reveal that motion can be seen independently of motion sensor output, based on attentive tracking of visual features. Sensor outputs are inherently ambiguous, due to the problem of univariance in neural responses. In order to compute stimulus direction and speed, the visual system must compare the responses of many different sensors sensitive to different directions and speeds. Physiological data show that this computation occurs in the visual middle temporal (MT) area. Recent psychophysical studies indicate that information about spatial form may also play a role in motion computations. Adaptation studies show that the human visual system is selectively sensitive to large-scale optic flow patterns, and physiological studies indicate that cells in the middle superior temporal (MST) area derive this sensitivity from the combined responses of many MT cells. Extraretinal signals used to control eye movements are an important source of signals to cancel out the retinal motion responses generated by eye movements, though visual information also plays a role. A number of issues remain to be resolved at all levels of the motion-processing hierarchy. WIREs Cogni Sci 2011 2 305-314 DOI: 10.1002/wcs.110 For further resources related to this article, please visit the WIREs website Additional Supporting Information may be found in http://www.lifesci.sussex.ac.uk/home/George_Mather/Motion/index.html. Copyright © 2010 John Wiley & Sons, Ltd.

Cross-National Comparisons of Background and Confidence in Visual Arts and Music Education of Pre-Service Primary Teachers

ERIC Educational Resources Information Center

Russell-Bowie, Deirdre

2010-01-01

This paper reports the findings of a study on pre-service teachers' background and confidence in music and visual arts education. The study involved 939 non-specialist pre-service primary teachers from five countries. Initially the paper identifies the students' perceptions of their background and confidence in relation to music and visual arts…

A neural correlate of working memory in the monkey primary visual cortex.

PubMed

Supèr, H; Spekreijse, H; Lamme, V A

2001-07-06

The brain frequently needs to store information for short periods. In vision, this means that the perceptual correlate of a stimulus has to be maintained temporally once the stimulus has been removed from the visual scene. However, it is not known how the visual system transfers sensory information into a memory component. Here, we identify a neural correlate of working memory in the monkey primary visual cortex (V1). We propose that this component may link sensory activity with memory activity.

Stochastic resonance in attention control

NASA Astrophysics Data System (ADS)

Kitajo, K.; Yamanaka, K.; Ward, L. M.; Yamamoto, Y.

2006-12-01

We investigated the beneficial role of noise in a human higher brain function, namely visual attention control. We asked subjects to detect a weak gray-level target inside a marker box either in the left or the right visual field. Signal detection performance was optimized by presenting a low level of randomly flickering gray-level noise between and outside the two possible target locations. Further, we found that an increase in eye movement (saccade) rate helped to compensate for the usual deterioration in detection performance at higher noise levels. To our knowledge, this is the first experimental evidence that noise can optimize a higher brain function which involves distinct brain regions above the level of primary sensory systems -- switching behavior between multi-stable attention states -- via the mechanism of stochastic resonance.

Seeing the world topsy-turvy: The primary role of kinematics in biological motion inversion effects

PubMed Central

Fitzgerald, Sue-Anne; Brooks, Anna; van der Zwan, Rick; Blair, Duncan

2014-01-01

Physical inversion of whole or partial human body representations typically has catastrophic consequences on the observer's ability to perform visual processing tasks. Explanations usually focus on the effects of inversion on the visual system's ability to exploit configural or structural relationships, but more recently have also implicated motion or kinematic cue processing. Here, we systematically tested the role of both on perceptions of sex from upright and inverted point-light walkers. Our data suggest that inversion results in systematic degradations of the processing of kinematic cues. Specifically and intriguingly, they reveal sex-based kinematic differences: Kinematics characteristic of females generally are resistant to inversion effects, while those of males drive systematic sex misperceptions. Implications of the findings are discussed. PMID:25469217

Basic instinct undressed: early spatiotemporal processing for primary sexual characteristics.

PubMed

Legrand, Lore B; Del Zotto, Marzia; Tyrand, Rémi; Pegna, Alan J

2013-01-01

This study investigates the spatiotemporal dynamics associated with conscious and non-conscious processing of naked and dressed human bodies. To this effect, stimuli of naked men and women with visible primary sexual characteristics, as well as dressed bodies, were presented to 20 heterosexual male and female participants while acquiring high resolution EEG data. The stimuli were either consciously detectable (supraliminal presentations) or were rendered non-conscious through backward masking (subliminal presentations). The N1 event-related potential component was significantly enhanced in participants when they viewed naked compared to dressed bodies under supraliminal viewing conditions. More importantly, naked bodies of the opposite sex produced a significantly greater N1 component compared to dressed bodies during subliminal presentations, when participants were not aware of the stimulus presented. A source localization algorithm computed on the N1 showed that the response for naked bodies in the supraliminal viewing condition was stronger in body processing areas, primary visual areas and additional structures related to emotion processing. By contrast, in the subliminal viewing condition, only visual and body processing areas were found to be activated. These results suggest that naked bodies and primary sexual characteristics are processed early in time (i.e., <200 ms) and activate key brain structures even when they are not consciously detected. It appears that, similarly to what has been reported for emotional faces, sexual features benefit from automatic and rapid processing, most likely due to their high relevance for the individual and their importance for the species in terms of reproductive success.

Alterations to global but not local motion processing in long-term ecstasy (MDMA) users.

PubMed

White, Claire; Brown, John; Edwards, Mark

2014-07-01

Growing evidence indicates that the main psychoactive ingredient in the illegal drug "ecstasy" (methylendioxymethamphetamine) causes reduced activity in the serotonin and gamma-aminobutyric acid (GABA) systems in humans. On the basis of substantial serotonin input to the occipital lobe, recent research investigated visual processing in long-term users and found a larger magnitude of the tilt aftereffect, interpreted to reflect broadened orientation tuning bandwidths. Further research found higher orientation discrimination thresholds and reduced long-range interactions in the primary visual area of ecstasy users. The aim of the present research was to investigate whether serotonin-mediated V1 visual processing deficits in ecstasy users extend to motion processing mechanisms. Forty-five participants (21 controls, 24 drug users) completed two psychophysical studies: A direction discrimination study directly measured local motion processing in V1, while a motion coherence task tested global motion processing in area V5/MT. "Primary" ecstasy users (n = 18), those without substantial polydrug use, had significantly lower global motion thresholds than controls [p = 0.027, Cohen's d = 0.78 (large)], indicating increased sensitivity to global motion stimuli, but no difference in local motion processing (p = 0.365). These results extend on previous research investigating the long-term effects of illicit drugs on visual processing. Two possible explanations are explored: defuse attentional processes may be facilitating spatial pooling of motion signals in users. Alternatively, it may be that a GABA-mediated disruption to V5/MT processing is reducing spatial suppression and therefore improving global motion perception in ecstasy users.

Image/video understanding systems based on network-symbolic models

NASA Astrophysics Data System (ADS)

Kuvich, Gary

2004-03-01

Vision is a part of a larger information system that converts visual information into knowledge structures. These structures drive vision process, resolve ambiguity and uncertainty via feedback projections, and provide image understanding that is an interpretation of visual information in terms of such knowledge models. Computer simulation models are built on the basis of graphs/networks. The ability of human brain to emulate similar graph/network models is found. Symbols, predicates and grammars naturally emerge in such networks, and logic is simply a way of restructuring such models. Brain analyzes an image as a graph-type relational structure created via multilevel hierarchical compression of visual information. Primary areas provide active fusion of image features on a spatial grid-like structure, where nodes are cortical columns. Spatial logic and topology naturally present in such structures. Mid-level vision processes like perceptual grouping, separation of figure from ground, are special kinds of network transformations. They convert primary image structure into the set of more abstract ones, which represent objects and visual scene, making them easy for analysis by higher-level knowledge structures. Higher-level vision phenomena are results of such analysis. Composition of network-symbolic models combines learning, classification, and analogy together with higher-level model-based reasoning into a single framework, and it works similar to frames and agents. Computational intelligence methods transform images into model-based knowledge representation. Based on such principles, an Image/Video Understanding system can convert images into the knowledge models, and resolve uncertainty and ambiguity. This allows creating intelligent computer vision systems for design and manufacturing.

Primary visual cortex in neandertals as revealed from the occipital remains from the El Sidrón site, with emphasis on the new SD-2300 specimen.

PubMed

García-Tabernero, Antonio; Peña-Melián, Angel; Rosas, Antonio

2018-07-01

The comparative analysis of the endocranial surface of the El Sidrón new occipital fragment SD-2300 shows meaningful differences in the configuration of the occipital pole region between neandertals and anatomically modern humans (AMH). The particular asymmetries found in neandertals in the venous sinus drainage and the petalial patterns are recognizable in this new specimen as well. In addition, the supra- and infracalcarine fossae of the occipital pole region appear to deviate obliquely from the mid-line when compared with sapiens. Due to the excellent preservation conditions of SD-2300, the main sulci and gyri of the occipital pole area have been identified, this degree of detail being uncommon in a fossil specimen; in general, the gyrification pattern is similar to AMH, but with some notable differences. Particularly interesting is the description of the lunate and the calcarine sulci. The lunate sulcus is located close to the occipital pole, in a similar posterior position to in other Homo species. Regarding the calcarine sulcus, there are significant differences in the primary visual cortex, with the V1 area, or Brodmann area 17, being larger in Homo neanderthalensis than in Homo sapiens. This may lead to greater visual acuity in neandertals than in sapiens. © 2018 Anatomical Society.

Temporal characteristics of audiovisual information processing.

PubMed

Fuhrmann Alpert, Galit; Hein, Grit; Tsai, Nancy; Naumer, Marcus J; Knight, Robert T

2008-05-14

In complex natural environments, auditory and visual information often have to be processed simultaneously. Previous functional magnetic resonance imaging (fMRI) studies focused on the spatial localization of brain areas involved in audiovisual (AV) information processing, but the temporal characteristics of AV information flow in these regions remained unclear. In this study, we used fMRI and a novel information-theoretic approach to study the flow of AV sensory information. Subjects passively perceived sounds and images of objects presented either alone or simultaneously. Applying the measure of mutual information, we computed for each voxel the latency in which the blood oxygenation level-dependent signal had the highest information content about the preceding stimulus. The results indicate that, after AV stimulation, the earliest informative activity occurs in right Heschl's gyrus, left primary visual cortex, and the posterior portion of the superior temporal gyrus, which is known as a region involved in object-related AV integration. Informative activity in the anterior portion of superior temporal gyrus, middle temporal gyrus, right occipital cortex, and inferior frontal cortex was found at a later latency. Moreover, AV presentation resulted in shorter latencies in multiple cortical areas compared with isolated auditory or visual presentation. The results provide evidence for bottom-up processing from primary sensory areas into higher association areas during AV integration in humans and suggest that AV presentation shortens processing time in early sensory cortices.

Contributions of visual and embodied expertise to body perception.

PubMed

Reed, Catherine L; Nyberg, Andrew A; Grubb, Jefferson D

2012-01-01

Recent research has demonstrated that our perception of the human body differs from that of inanimate objects. This study investigated whether the visual perception of the human body differs from that of other animate bodies and, if so, whether that difference could be attributed to visual experience and/or embodied experience. To dissociate differential effects of these two types of expertise, inversion effects (recognition of inverted stimuli is slower and less accurate than recognition of upright stimuli) were compared for two types of bodies in postures that varied in typicality: humans in human postures (human-typical), humans in dog postures (human-atypical), dogs in dog postures (dog-typical), and dogs in human postures (dog-atypical). Inversion disrupts global configural processing. Relative changes in the size and presence of inversion effects reflect changes in visual processing. Both visual and embodiment expertise predict larger inversion effects for human over dog postures because we see humans more and we have experience producing human postures. However, our design that crosses body type and typicality leads to distinct predictions for visual and embodied experience. Visual expertise predicts an interaction between typicality and orientation: greater inversion effects should be found for typical over atypical postures regardless of body type. Alternatively, embodiment expertise predicts a body, typicality, and orientation interaction: larger inversion effects should be found for all human postures but only for atypical dog postures because humans can map their bodily experience onto these postures. Accuracy data supported embodiment expertise with the three-way interaction. However, response-time data supported contributions of visual expertise with larger inversion effects for typical over atypical postures. Thus, both types of expertise affect the visual perception of bodies.

Development of visual category selectivity in ventral visual cortex does not require visual experience

PubMed Central

van den Hurk, Job; Van Baelen, Marc; Op de Beeck, Hans P.

2017-01-01

To what extent does functional brain organization rely on sensory input? Here, we show that for the penultimate visual-processing region, ventral-temporal cortex (VTC), visual experience is not the origin of its fundamental organizational property, category selectivity. In the fMRI study reported here, we presented 14 congenitally blind participants with face-, body-, scene-, and object-related natural sounds and presented 20 healthy controls with both auditory and visual stimuli from these categories. Using macroanatomical alignment, response mapping, and surface-based multivoxel pattern analysis, we demonstrated that VTC in blind individuals shows robust discriminatory responses elicited by the four categories and that these patterns of activity in blind subjects could successfully predict the visual categories in sighted controls. These findings were confirmed in a subset of blind participants born without eyes and thus deprived from all light perception since conception. The sounds also could be decoded in primary visual and primary auditory cortex, but these regions did not sustain generalization across modalities. Surprisingly, although not as strong as visual responses, selectivity for auditory stimulation in visual cortex was stronger in blind individuals than in controls. The opposite was observed in primary auditory cortex. Overall, we demonstrated a striking similarity in the cortical response layout of VTC in blind individuals and sighted controls, demonstrating that the overall category-selective map in extrastriate cortex develops independently from visual experience. PMID:28507127

Characterization of the blood-oxygen level-dependent (BOLD) response in cat auditory cortex using high-field fMRI.

PubMed

Brown, Trecia A; Joanisse, Marc F; Gati, Joseph S; Hughes, Sarah M; Nixon, Pam L; Menon, Ravi S; Lomber, Stephen G

2013-01-01

Much of what is known about the cortical organization for audition in humans draws from studies of auditory cortex in the cat. However, these data build largely on electrophysiological recordings that are both highly invasive and provide less evidence concerning macroscopic patterns of brain activation. Optical imaging, using intrinsic signals or dyes, allows visualization of surface-based activity but is also quite invasive. Functional magnetic resonance imaging (fMRI) overcomes these limitations by providing a large-scale perspective of distributed activity across the brain in a non-invasive manner. The present study used fMRI to characterize stimulus-evoked activity in auditory cortex of an anesthetized (ketamine/isoflurane) cat, focusing specifically on the blood-oxygen-level-dependent (BOLD) signal time course. Functional images were acquired for adult cats in a 7 T MRI scanner. To determine the BOLD signal time course, we presented 1s broadband noise bursts between widely spaced scan acquisitions at randomized delays (1-12 s in 1s increments) prior to each scan. Baseline trials in which no stimulus was presented were also acquired. Our results indicate that the BOLD response peaks at about 3.5s in primary auditory cortex (AI) and at about 4.5 s in non-primary areas (AII, PAF) of cat auditory cortex. The observed peak latency is within the range reported for humans and non-human primates (3-4 s). The time course of hemodynamic activity in cat auditory cortex also occurs on a comparatively shorter scale than in cat visual cortex. The results of this study will provide a foundation for future auditory fMRI studies in the cat to incorporate these hemodynamic response properties into appropriate analyses of cat auditory cortex. Copyright © 2012 Elsevier Inc. All rights reserved.

Decoding the individual finger movements from single-trial functional magnetic resonance imaging recordings of human brain activity.

PubMed

Shen, Guohua; Zhang, Jing; Wang, Mengxing; Lei, Du; Yang, Guang; Zhang, Shanmin; Du, Xiaoxia

2014-06-01

Multivariate pattern classification analysis (MVPA) has been applied to functional magnetic resonance imaging (fMRI) data to decode brain states from spatially distributed activation patterns. Decoding upper limb movements from non-invasively recorded human brain activation is crucial for implementing a brain-machine interface that directly harnesses an individual's thoughts to control external devices or computers. The aim of this study was to decode the individual finger movements from fMRI single-trial data. Thirteen healthy human subjects participated in a visually cued delayed finger movement task, and only one slight button press was performed in each trial. Using MVPA, the decoding accuracy (DA) was computed separately for the different motor-related regions of interest. For the construction of feature vectors, the feature vectors from two successive volumes in the image series for a trial were concatenated. With these spatial-temporal feature vectors, we obtained a 63.1% average DA (84.7% for the best subject) for the contralateral primary somatosensory cortex and a 46.0% average DA (71.0% for the best subject) for the contralateral primary motor cortex; both of these values were significantly above the chance level (20%). In addition, we implemented searchlight MVPA to search for informative regions in an unbiased manner across the whole brain. Furthermore, by applying searchlight MVPA to each volume of a trial, we visually demonstrated the information for decoding, both spatially and temporally. The results suggest that the non-invasive fMRI technique may provide informative features for decoding individual finger movements and the potential of developing an fMRI-based brain-machine interface for finger movement. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Structural and Functional Correlates of Visual Field Asymmetry in the Human Brain by Diffusion Kurtosis MRI and Functional MRI

PubMed Central

O’Connell, Caitlin; Ho, Leon C.; Murphy, Matthew C.; Conner, Ian P.; Wollstein, Gadi; Cham, Rakie; Chan, Kevin C.

2016-01-01

Human visual performance has been observed to exhibit superiority in localized regions of the visual field across many classes of stimuli. However, the underlying neural mechanisms remain unclear. This study aims to determine if the visual information processing in the human brain is dependent on the location of stimuli in the visual field and the corresponding neuroarchitecture using blood-oxygenation-level-dependent functional MRI (fMRI) and diffusion kurtosis MRI (DKI), respectively in 15 healthy individuals at 3 Tesla. In fMRI, visual stimulation to the lower hemifield showed stronger brain responses and larger brain activation volumes than the upper hemifield, indicative of the differential sensitivity of the human brain across the visual field. In DKI, the brain regions mapping to the lower visual field exhibited higher mean kurtosis but not fractional anisotropy or mean diffusivity when compared to the upper visual field. These results suggested the different distributions of microstructural organization across visual field brain representations. There was also a strong positive relationship between diffusion kurtosis and fMRI responses in the lower field brain representations. In summary, this study suggested the structural and functional brain involvements in the asymmetry of visual field responses in humans, and is important to the neurophysiological and psychological understanding of human visual information processing. PMID:27631541

Determining the Appropriateness of Visual Based Activities in the Primary School Books for Low Vision Students

ERIC Educational Resources Information Center

Cakmak, Salih; Yilmaz, Hatice Cansu; Isitan, Hacer Damlanur

2017-01-01

The general aim of this research is to try to determine the appropriateness of the visuals in the primary school Turkish workbooks for the students with low visibility in terms of visual design elements. In the realization of the work, the document review method was used. In this study, purposive sampling method was used in the selection of…

How cortical neurons help us see: visual recognition in the human brain

PubMed Central

Blumberg, Julie; Kreiman, Gabriel

2010-01-01

Through a series of complex transformations, the pixel-like input to the retina is converted into rich visual perceptions that constitute an integral part of visual recognition. Multiple visual problems arise due to damage or developmental abnormalities in the cortex of the brain. Here, we provide an overview of how visual information is processed along the ventral visual cortex in the human brain. We discuss how neurophysiological recordings in macaque monkeys and in humans can help us understand the computations performed by visual cortex. PMID:20811161

iELVis: An open source MATLAB toolbox for localizing and visualizing human intracranial electrode data.

PubMed

Groppe, David M; Bickel, Stephan; Dykstra, Andrew R; Wang, Xiuyuan; Mégevand, Pierre; Mercier, Manuel R; Lado, Fred A; Mehta, Ashesh D; Honey, Christopher J

2017-04-01

Intracranial electrical recordings (iEEG) and brain stimulation (iEBS) are invaluable human neuroscience methodologies. However, the value of such data is often unrealized as many laboratories lack tools for localizing electrodes relative to anatomy. To remedy this, we have developed a MATLAB toolbox for intracranial electrode localization and visualization, iELVis. NEW METHOD: iELVis uses existing tools (BioImage Suite, FSL, and FreeSurfer) for preimplant magnetic resonance imaging (MRI) segmentation, neuroimaging coregistration, and manual identification of electrodes in postimplant neuroimaging. Subsequently, iELVis implements methods for correcting electrode locations for postimplant brain shift with millimeter-scale accuracy and provides interactive visualization on 3D surfaces or in 2D slices with optional functional neuroimaging overlays. iELVis also localizes electrodes relative to FreeSurfer-based atlases and can combine data across subjects via the FreeSurfer average brain. It takes 30-60min of user time and 12-24h of computer time to localize and visualize electrodes from one brain. We demonstrate iELVis's functionality by showing that three methods for mapping primary hand somatosensory cortex (iEEG, iEBS, and functional MRI) provide highly concordant results. COMPARISON WITH EXISTING METHODS: iELVis is the first public software for electrode localization that corrects for brain shift, maps electrodes to an average brain, and supports neuroimaging overlays. Moreover, its interactive visualizations are powerful and its tutorial material is extensive. iELVis promises to speed the progress and enhance the robustness of intracranial electrode research. The software and extensive tutorial materials are freely available as part of the EpiSurg software project: https://github.com/episurg/episurg. Copyright © 2017 Elsevier B.V. All rights reserved.

"Usability of data integration and visualization software for multidisciplinary pediatric intensive care: a human factors approach to assessing technology".

PubMed

Lin, Ying Ling; Guerguerian, Anne-Marie; Tomasi, Jessica; Laussen, Peter; Trbovich, Patricia

2017-08-14

Intensive care clinicians use several sources of data in order to inform decision-making. We set out to evaluate a new interactive data integration platform called T3™ made available for pediatric intensive care. Three primary functions are supported: tracking of physiologic signals, displaying trajectory, and triggering decisions, by highlighting data or estimating risk of patient instability. We designed a human factors study to identify interface usability issues, to measure ease of use, and to describe interface features that may enable or hinder clinical tasks. Twenty-two participants, consisting of bedside intensive care physicians, nurses, and respiratory therapists, tested the T3™ interface in a simulation laboratory setting. Twenty tasks were performed with a true-to-setting, fully functional, prototype, populated with physiological and therapeutic intervention patient data. Primary data visualization was time series and secondary visualizations were: 1) shading out-of-target values, 2) mini-trends with exaggerated maxima and minima (sparklines), and 3) bar graph of a 16-parameter indicator. Task completion was video recorded and assessed using a use error rating scale. Usability issues were classified in the context of task and type of clinician. A severity rating scale was used to rate potential clinical impact of usability issues. Time series supported tracking a single parameter but partially supported determining patient trajectory using multiple parameters. Visual pattern overload was observed with multiple parameter data streams. Automated data processing using shading and sparklines was often ignored but the 16-parameter data reduction algorithm, displayed as a persistent bar graph, was visually intuitive. However, by selecting or automatically processing data, triggering aids distorted the raw data that clinicians use regularly. Consequently, clinicians could not rely on new data representations because they did not know how they were established or derived. Usability issues, observed through contextual use, provided directions for tangible design improvements of data integration software that may lessen use errors and promote safe use. Data-driven decision making can benefit from iterative interface redesign involving clinician-users in simulated environments. This study is a first step in understanding how software can support clinicians' decision making with integrated continuous monitoring data. Importantly, testing of similar platforms by all the different disciplines who may become clinician users is a fundamental step necessary to understand the impact on clinical outcomes of decision aids.

Psychophysics and Neuronal Bases of Sound Localization in Humans

PubMed Central

Ahveninen, Jyrki; Kopco, Norbert; Jääskeläinen, Iiro P.

2013-01-01

Localization of sound sources is a considerable computational challenge for the human brain. Whereas the visual system can process basic spatial information in parallel, the auditory system lacks a straightforward correspondence between external spatial locations and sensory receptive fields. Consequently, the question how different acoustic features supporting spatial hearing are represented in the central nervous system is still open. Functional neuroimaging studies in humans have provided evidence for a posterior auditory “where” pathway that encompasses non-primary auditory cortex areas, including the planum temporale (PT) and posterior superior temporal gyrus (STG), which are strongly activated by horizontal sound direction changes, distance changes, and movement. However, these areas are also activated by a wide variety of other stimulus features, posing a challenge for the interpretation that the underlying areas are purely spatial. This review discusses behavioral and neuroimaging studies on sound localization, and some of the competing models of representation of auditory space in humans. PMID:23886698

Real-time confocal laser endomicroscopic evaluation of primary liver cancer based on human liver autofluorescence.

PubMed

Maki, Harufumi; Kawaguchi, Yoshikuni; Arita, Junichi; Akamatsu, Nobuhisa; Kaneko, Junichi; Sakamoto, Yoshihiro; Hasegawa, Kiyoshi; Harihara, Yasushi; Kokudo, Norihiro

2017-02-01

Confocal laser endomicroscopy (CLE) is available for real-time microscopic examination. This study aims to evaluate the usefulness of intraoperative CLE examination as a modality to evaluate surgical margins in surgery for primary liver cancer. A probe-based CLE system (Cellvizio 100, Mauna Kea Technologies, Paris, France) was used. The subjects comprised seven specimens obtained from six patients with primary liver cancer in November 2015. The probe was manually attached to the surfaces of specimens, and images were collected without external fluorophores. CLE images were compared with hematoxylin and eosin-stained slides. Fluorescence intensity (FI) values of the CLE images were assessed using luminance-analyzing software. CLE examination visualized non-cancerous regions in the background liver as regular structures with high fluorescence because of human liver autofluorescence. Conversely, hepatocellular carcinoma and intrahepatic cholangiocarcinoma were depicted as irregular structures with low fluorescence. The median FI values of the non-cancerous regions and the cancerous regions were 104 (79.8-156) and 74.9 (60.6-106), respectively, and were significantly different (P = 0.031). The probe-based CLE enables real-time differentiation of cancerous regions from non-cancerous tissues in surgical specimens because of human liver autofluorescence. CLE can be used to confirm negative surgical margins in the operating room. J. Surg. Oncol. 2017;115:151-157. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Comparison of deep neural networks to spatio-temporal cortical dynamics of human visual object recognition reveals hierarchical correspondence

PubMed Central

Cichy, Radoslaw Martin; Khosla, Aditya; Pantazis, Dimitrios; Torralba, Antonio; Oliva, Aude

2016-01-01

The complex multi-stage architecture of cortical visual pathways provides the neural basis for efficient visual object recognition in humans. However, the stage-wise computations therein remain poorly understood. Here, we compared temporal (magnetoencephalography) and spatial (functional MRI) visual brain representations with representations in an artificial deep neural network (DNN) tuned to the statistics of real-world visual recognition. We showed that the DNN captured the stages of human visual processing in both time and space from early visual areas towards the dorsal and ventral streams. Further investigation of crucial DNN parameters revealed that while model architecture was important, training on real-world categorization was necessary to enforce spatio-temporal hierarchical relationships with the brain. Together our results provide an algorithmically informed view on the spatio-temporal dynamics of visual object recognition in the human visual brain. PMID:27282108

Comparison of deep neural networks to spatio-temporal cortical dynamics of human visual object recognition reveals hierarchical correspondence.

PubMed

Cichy, Radoslaw Martin; Khosla, Aditya; Pantazis, Dimitrios; Torralba, Antonio; Oliva, Aude

2016-06-10

The complex multi-stage architecture of cortical visual pathways provides the neural basis for efficient visual object recognition in humans. However, the stage-wise computations therein remain poorly understood. Here, we compared temporal (magnetoencephalography) and spatial (functional MRI) visual brain representations with representations in an artificial deep neural network (DNN) tuned to the statistics of real-world visual recognition. We showed that the DNN captured the stages of human visual processing in both time and space from early visual areas towards the dorsal and ventral streams. Further investigation of crucial DNN parameters revealed that while model architecture was important, training on real-world categorization was necessary to enforce spatio-temporal hierarchical relationships with the brain. Together our results provide an algorithmically informed view on the spatio-temporal dynamics of visual object recognition in the human visual brain.

The neural basis of suppression and amblyopia in strabismus.

PubMed

Sengpiel, F; Blakemore, C

1996-01-01

The neurophysiological consequences of artificial strabismus in cats and monkeys have been studied for 30 years. However, until very recently no clear picture has emerged of neural deficits that might account for the powerful interocular suppression that strabismic humans experience, nor for the severe amblyopia that is often associated with convergent strabismus. Here we review the effects of squint on the integrative capacities of the primary visual cortex and propose a hypothesis about the relationship between suppression and amblyopia. Most neurons in the visual cortex of normal cats and monkeys can be excited through either eye and show strong facilitation during binocular stimulation with contours of similar orientation in the two eyes. But in strabismic animals, cortical neurons tend to fall into two populations of monocularly excitable cells and exhibit suppressive binocular interactions that share key properties with perceptual suppression in strabismic humans. Such interocular suppression, if prolonged and asymmetric (with input from the squinting eye habitually suppressed by that from the fixating eye), might lead to neural defects in the representation of the deviating eye and hence to amblyopia.

Neuroimaging of amblyopia and binocular vision: a review

PubMed Central

Joly, Olivier; Frankó, Edit

2014-01-01

Amblyopia is a cerebral visual impairment considered to derive from abnormal visual experience (e.g., strabismus, anisometropia). Amblyopia, first considered as a monocular disorder, is now often seen as a primarily binocular disorder resulting in more and more studies examining the binocular deficits in the patients. The neural mechanisms of amblyopia are not completely understood even though they have been investigated with electrophysiological recordings in animal models and more recently with neuroimaging techniques in humans. In this review, we summarize the current knowledge about the brain regions that underlie the visual deficits associated with amblyopia with a focus on binocular vision using functional magnetic resonance imaging. The first studies focused on abnormal responses in the primary and secondary visual areas whereas recent evidence shows that there are also deficits at higher levels of the visual pathways within the parieto-occipital and temporal cortices. These higher level areas are part of the cortical network involved in 3D vision from binocular cues. Therefore, reduced responses in these areas could be related to the impaired binocular vision in amblyopic patients. Promising new binocular treatments might at least partially correct the activation in these areas. Future neuroimaging experiments could help to characterize the brain response changes associated with these treatments and help devise them. PMID:25147511

Common Sense in Choice: The Effect of Sensory Modality on Neural Value Representations.

PubMed

Shuster, Anastasia; Levy, Dino J

2018-01-01

Although it is well established that the ventromedial prefrontal cortex (vmPFC) represents value using a common currency across categories of rewards, it is unknown whether the vmPFC represents value irrespective of the sensory modality in which alternatives are presented. In the current study, male and female human subjects completed a decision-making task while their neural activity was recorded using functional magnetic resonance imaging. On each trial, subjects chose between a safe alternative and a lottery, which was presented visually or aurally. A univariate conjunction analysis revealed that the anterior portion of the vmPFC tracks subjective value (SV) irrespective of the sensory modality. Using a novel cross-modality multivariate classifier, we were able to decode auditory value based on visual trials and vice versa. In addition, we found that the visual and auditory sensory cortices, which were identified using functional localizers, are also sensitive to the value of stimuli, albeit in a modality-specific manner. Whereas both primary and higher-order auditory cortices represented auditory SV (aSV), only a higher-order visual area represented visual SV (vSV). These findings expand our understanding of the common currency network of the brain and shed a new light on the interplay between sensory and value information processing.

Common Sense in Choice: The Effect of Sensory Modality on Neural Value Representations

PubMed Central

2018-01-01

Abstract Although it is well established that the ventromedial prefrontal cortex (vmPFC) represents value using a common currency across categories of rewards, it is unknown whether the vmPFC represents value irrespective of the sensory modality in which alternatives are presented. In the current study, male and female human subjects completed a decision-making task while their neural activity was recorded using functional magnetic resonance imaging. On each trial, subjects chose between a safe alternative and a lottery, which was presented visually or aurally. A univariate conjunction analysis revealed that the anterior portion of the vmPFC tracks subjective value (SV) irrespective of the sensory modality. Using a novel cross-modality multivariate classifier, we were able to decode auditory value based on visual trials and vice versa. In addition, we found that the visual and auditory sensory cortices, which were identified using functional localizers, are also sensitive to the value of stimuli, albeit in a modality-specific manner. Whereas both primary and higher-order auditory cortices represented auditory SV (aSV), only a higher-order visual area represented visual SV (vSV). These findings expand our understanding of the common currency network of the brain and shed a new light on the interplay between sensory and value information processing. PMID:29619408

Neuroimaging of amblyopia and binocular vision: a review.

PubMed

Joly, Olivier; Frankó, Edit

2014-01-01

Amblyopia is a cerebral visual impairment considered to derive from abnormal visual experience (e.g., strabismus, anisometropia). Amblyopia, first considered as a monocular disorder, is now often seen as a primarily binocular disorder resulting in more and more studies examining the binocular deficits in the patients. The neural mechanisms of amblyopia are not completely understood even though they have been investigated with electrophysiological recordings in animal models and more recently with neuroimaging techniques in humans. In this review, we summarize the current knowledge about the brain regions that underlie the visual deficits associated with amblyopia with a focus on binocular vision using functional magnetic resonance imaging. The first studies focused on abnormal responses in the primary and secondary visual areas whereas recent evidence shows that there are also deficits at higher levels of the visual pathways within the parieto-occipital and temporal cortices. These higher level areas are part of the cortical network involved in 3D vision from binocular cues. Therefore, reduced responses in these areas could be related to the impaired binocular vision in amblyopic patients. Promising new binocular treatments might at least partially correct the activation in these areas. Future neuroimaging experiments could help to characterize the brain response changes associated with these treatments and help devise them.

A Graphics Design Framework to Visualize Multi-Dimensional Economic Datasets

ERIC Educational Resources Information Center

Chandramouli, Magesh; Narayanan, Badri; Bertoline, Gary R.

2013-01-01

This study implements a prototype graphics visualization framework to visualize multidimensional data. This graphics design framework serves as a "visual analytical database" for visualization and simulation of economic models. One of the primary goals of any kind of visualization is to extract useful information from colossal volumes of…

Microstimulation with Chronically Implanted Intracortical Electrodes

NASA Astrophysics Data System (ADS)

McCreery, Douglas

Stimulating microelectrodes that penetrate into the brain afford a means of accessing the basic functional units of the central nervous system. Microstimulation in the region of the cerebral cortex that subserve vision may be an alternative, or an adjunct, to a retinal prosthesis, and may be particularly attractive as a means of restoring a semblance of high-resolution central vision. There also is the intriguing possibility that such a prosthesis could convey higher order visual percepts, many of which are mediated by neural circuits in the secondary or "extra-striate" visual areas that surround the primary visual cortex. The technologies of intracortical stimulating microelectrodes and investigations of the effects of microstimulation on neural tissue have advanced to the point where a cortical-level prosthesis is at least feasible. The imperative of protecting neural tissue from stimulation-induced damage imposes constraints on the selection of stimulus parameters, as does the requirement that the stimulation not greatly affect the electrical excitability of the neurons that are to be activated. The latter is especially likely to occur when many adjacent microelectrodes are pulsed, as will be necessary in a visual prosthesis. However, data from animal studies indicates that these restrictions on stimulus parameter are compatible with those that can evoke visual percepts in humans and in experimental animals. These findings give cause to be optimistic about the prospects for realizing a visual prosthesis utilizing intracortical microstimulation.

Sharing control between humans and automation using haptic interface: primary and secondary task performance benefits.

PubMed

Griffiths, Paul G; Gillespie, R Brent

2005-01-01

This paper describes a paradigm for human/automation control sharing in which the automation acts through a motor coupled to a machine's manual control interface. The manual interface becomes a haptic display, continually informing the human about automation actions. While monitoring by feel, users may choose either to conform to the automation or override it and express their own control intentions. This paper's objective is to demonstrate that adding automation through haptic display can be used not only to improve performance on a primary task but also to reduce perceptual demands or free attention for a secondary task. Results are presented from three experiments in which 11 participants completed a lane-following task using a motorized steering wheel on a fixed-base driving simulator. The automation behaved like a copilot, assisting with lane following by applying torques to the steering wheel. Results indicate that haptic assist improves lane following by least 30%, p < .0001, while reducing visual demand by 29%, p < .0001, or improving reaction time in a secondary tone localization task by 18 ms, p = .0009. Potential applications of this research include the design of automation interfaces based on haptics that support human/automation control sharing better than traditional push-button automation interfaces.

Experience, Context, and the Visual Perception of Human Movement

ERIC Educational Resources Information Center

Jacobs, Alissa; Pinto, Jeannine; Shiffrar, Maggie

2004-01-01

Why are human observers particularly sensitive to human movement? Seven experiments examined the roles of visual experience and motor processes in human movement perception by comparing visual sensitivities to point-light displays of familiar, unusual, and impossible gaits across gait-speed and identity discrimination tasks. In both tasks, visual…

Levels of Antibodies against Human Heat Shock Protein (HSP) 60 in Patients with Glaucoma in Poland

PubMed Central

Grabska-Liberek, Iwona; Skonieczna, Katarzyna; Olesińska, Marzena; Terelak-Borys, Barbara; Kocięcki, Jarosandlstrokaw; Sikora, Mariusz; Jamrozy-Witkowska, Agnieszka; Tesla, Piotr; Czarnocka, Barbara

2015-01-01

Background Although elevated intraocular pressure is a major risk factor for the development of glaucoma, there is increasing evidence that the immune system may be involved in the development of normal-tension glaucoma (NTG). The aim of this study was to determine if NTG is associated with elevated levels of antibodies against human heat shock protein (HSP) 60. Material/Methods The study was conducted in 139 subjects (35 subjects with NTG [Group 1], 34 subjects with primary open-angle glaucoma/POAG/[Group 2], 24 subjects with autoimmune rheumatic diseases [Group 3], and 36 healthy controls [Group 4]). All subjects had complete ophthalmologic examination (visual acuity, slit-lamp examination, tonometry, gonioscopy; visual-field examination, and optical coherence tomography/OCT/of the optic nerve head and the macula). Blood samples were collected for the measurements of serum levels of antibodies against human HSP60. Results The subjects with rheumatic diseases had the highest median serum level of antibodies against HSP60 – 20.49 ng/mL. The values in the subjects with NTG, POAG, and in controls were 18.79 ng/mL, 18.61 ng/mL and 17.61 ng/mL, respectively (p=0.96). Conclusions This study does not confirm the hypothesis that normal-tension glaucoma is associated with elevated blood levels of antibodies against human heat shock protein (HSP) 60. PMID:25786333

Mapping visual cortex in monkeys and humans using surface-based atlases

NASA Technical Reports Server (NTRS)

Van Essen, D. C.; Lewis, J. W.; Drury, H. A.; Hadjikhani, N.; Tootell, R. B.; Bakircioglu, M.; Miller, M. I.

2001-01-01

We have used surface-based atlases of the cerebral cortex to analyze the functional organization of visual cortex in humans and macaque monkeys. The macaque atlas contains multiple partitioning schemes for visual cortex, including a probabilistic atlas of visual areas derived from a recent architectonic study, plus summary schemes that reflect a combination of physiological and anatomical evidence. The human atlas includes a probabilistic map of eight topographically organized visual areas recently mapped using functional MRI. To facilitate comparisons between species, we used surface-based warping to bring functional and geographic landmarks on the macaque map into register with corresponding landmarks on the human map. The results suggest that extrastriate visual cortex outside the known topographically organized areas is dramatically expanded in human compared to macaque cortex, particularly in the parietal lobe.

Simulating Visual Attention Allocation of Pilots in an Advanced Cockpit Environment

NASA Technical Reports Server (NTRS)

Frische, F.; Osterloh, J.-P.; Luedtke, A.

2011-01-01

This paper describes the results of experiments conducted with human line pilots and a cognitive pilot model during interaction with a new 40 Flight Management System (FMS). The aim of these experiments was to gather human pilot behavior data in order to calibrate the behavior of the model. Human behavior is mainly triggered by visual perception. Thus, the main aspect was to setup a profile of human pilots' visual attention allocation in a cockpit environment containing the new FMS. We first performed statistical analyses of eye tracker data and then compared our results to common results of familiar analyses in standard cockpit environments. The comparison has shown a significant influence of the new system on the visual performance of human pilots. Further on, analyses of the pilot models' visual performance have been performed. A comparison to human pilots' visual performance revealed important improvement potentials.

Photogenic partial seizures.

PubMed

Hennessy, M J; Binnie, C D

2000-01-01

To establish the incidence and symptoms of partial seizures in a cohort of patients investigated on account of known sensitivity to intermittent photic stimulation and/or precipitation of seizures by environmental visual stimuli such as television (TV) screens or computer monitors. We report 43 consecutive patients with epilepsy, who had exhibited a significant EEG photoparoxysmal response or who had seizures precipitated by environmental visual stimuli and underwent detailed assessment of their photosensitivity in the EEG laboratory, during which all were questioned concerning their ictal symptoms. All patients were considered on clinical grounds to have an idiopathic epilepsy syndrome. Twenty-eight (65%) patients reported visually precipitated attacks occurring initially with maintained consciousness, in some instances evolving to a period of confusion or to a secondarily generalized seizure. Visual symptoms were most commonly reported and included positive symptoms such as coloured circles or spots, but also blindness and subjective symptoms such as "eyes going funny." Other symptoms described included nonspecific cephalic sensations, deja-vu, auditory hallucinations, nausea, and vomiting. No patient reported any clear spontaneous partial seizures, and there were no grounds for supposing that any had partial epilepsy excepting the ictal phenomenology of some or all of the visually induced attacks. These findings provide clinical support for the physiological studies that indicate that the trigger mechanism for human photosensitivity involves binocularly innervated cells located in the visual cortex. Thus the visual cortex is the seat of the primary epileptogenic process, and the photically triggered discharges and seizures may be regarded as partial with secondary generalization.

Gravity influences top-down signals in visual processing.

PubMed

Cheron, Guy; Leroy, Axelle; Palmero-Soler, Ernesto; De Saedeleer, Caty; Bengoetxea, Ana; Cebolla, Ana-Maria; Vidal, Manuel; Dan, Bernard; Berthoz, Alain; McIntyre, Joseph

2014-01-01

Visual perception is not only based on incoming visual signals but also on information about a multimodal reference frame that incorporates vestibulo-proprioceptive input and motor signals. In addition, top-down modulation of visual processing has previously been demonstrated during cognitive operations including selective attention and working memory tasks. In the absence of a stable gravitational reference, the updating of salient stimuli becomes crucial for successful visuo-spatial behavior by humans in weightlessness. Here we found that visually-evoked potentials triggered by the image of a tunnel just prior to an impending 3D movement in a virtual navigation task were altered in weightlessness aboard the International Space Station, while those evoked by a classical 2D-checkerboard were not. Specifically, the analysis of event-related spectral perturbations and inter-trial phase coherency of these EEG signals recorded in the frontal and occipital areas showed that phase-locking of theta-alpha oscillations was suppressed in weightlessness, but only for the 3D tunnel image. Moreover, analysis of the phase of the coherency demonstrated the existence on Earth of a directional flux in the EEG signals from the frontal to the occipital areas mediating a top-down modulation during the presentation of the image of the 3D tunnel. In weightlessness, this fronto-occipital, top-down control was transformed into a diverging flux from the central areas toward the frontal and occipital areas. These results demonstrate that gravity-related sensory inputs modulate primary visual areas depending on the affordances of the visual scene.

Helmet-mounted pilot night vision systems: Human factors issues

NASA Technical Reports Server (NTRS)

Hart, Sandra G.; Brickner, Michael S.

1989-01-01

Helmet-mounted displays of infrared imagery (forward-looking infrared (FLIR)) allow helicopter pilots to perform low level missions at night and in low visibility. However, pilots experience high visual and cognitive workload during these missions, and their performance capabilities may be reduced. Human factors problems inherent in existing systems stem from three primary sources: the nature of thermal imagery; the characteristics of specific FLIR systems; and the difficulty of using FLIR system for flying and/or visually acquiring and tracking objects in the environment. The pilot night vision system (PNVS) in the Apache AH-64 provides a monochrome, 30 by 40 deg helmet-mounted display of infrared imagery. Thermal imagery is inferior to television imagery in both resolution and contrast ratio. Gray shades represent temperatures differences rather than brightness variability, and images undergo significant changes over time. The limited field of view, displacement of the sensor from the pilot's eye position, and monocular presentation of a bright FLIR image (while the other eye remains dark-adapted) are all potential sources of disorientation, limitations in depth and distance estimation, sensations of apparent motion, and difficulties in target and obstacle detection. Insufficient information about human perceptual and performance limitations restrains the ability of human factors specialists to provide significantly improved specifications, training programs, or alternative designs. Additional research is required to determine the most critical problem areas and to propose solutions that consider the human as well as the development of technology.

Alpha-beta and gamma rhythms subserve feedback and feedforward influences among human visual cortical areas

PubMed Central

Michalareas, Georgios; Vezoli, Julien; van Pelt, Stan; Schoffelen, Jan-Mathijs; Kennedy, Henry; Fries, Pascal

2016-01-01

Primate visual cortex is hierarchically organized. Bottom-up and top-down influences are exerted through distinct frequency channels, as was recently revealed in macaques by correlating inter-areal influences with laminar anatomical projection patterns. Because this anatomical data cannot be obtained in human subjects, we selected seven homologous macaque and human visual areas, and correlated the macaque laminar projection patterns to human inter-areal directed influences as measured with magnetoencephalography. We show that influences along feedforward projections predominate in the gamma band, whereas influences along feedback projections predominate in the alpha-beta band. Rhythmic inter-areal influences constrain a functional hierarchy of the seven homologous human visual areas that is in close agreement with the respective macaque anatomical hierarchy. Rhythmic influences allow an extension of the hierarchy to 26 human visual areas including uniquely human brain areas. Hierarchical levels of ventral and dorsal stream visual areas are differentially affected by inter-areal influences in the alpha-beta band. PMID:26777277

Plastic Bags and Environmental Pollution

ERIC Educational Resources Information Center

Sang, Anita Ng Heung

2010-01-01

The "Hong Kong Visual Arts Curriculum Guide," covering Primary 1 to Secondary 3 grades (Curriculum Development Committee, 2003), points to three domains of learning in visual arts: (1) visual arts knowledge; (2) visual arts appreciation and criticism; and (3) visual arts making. The "Guide" suggests learning should develop…

The Neural Basis of Mark Making: A Functional MRI Study of Drawing

PubMed Central

Yuan, Ye; Brown, Steven

2014-01-01

Compared to most other forms of visually-guided motor activity, drawing is unique in that it “leaves a trail behind” in the form of the emanating image. We took advantage of an MRI-compatible drawing tablet in order to examine both the motor production and perceptual emanation of images. Subjects participated in a series of mark making tasks in which they were cued to draw geometric patterns on the tablet's surface. The critical comparison was between when visual feedback was displayed (image generation) versus when it was not (no image generation). This contrast revealed an occipito-parietal stream involved in motion-based perception of the emerging image, including areas V5/MT+, LO, V3A, and the posterior part of the intraparietal sulcus. Interestingly, when subjects passively viewed animations of visual patterns emerging on the projected surface, all of the sensorimotor network involved in drawing was strongly activated, with the exception of the primary motor cortex. These results argue that the origin of the human capacity to draw and write involves not only motor skills for tool use but also motor-sensory links between drawing movements and the visual images that emanate from them in real time. PMID:25271440

Supranormal orientation selectivity of visual neurons in orientation-restricted animals.

PubMed

Sasaki, Kota S; Kimura, Rui; Ninomiya, Taihei; Tabuchi, Yuka; Tanaka, Hiroki; Fukui, Masayuki; Asada, Yusuke C; Arai, Toshiya; Inagaki, Mikio; Nakazono, Takayuki; Baba, Mika; Kato, Daisuke; Nishimoto, Shinji; Sanada, Takahisa M; Tani, Toshiki; Imamura, Kazuyuki; Tanaka, Shigeru; Ohzawa, Izumi

2015-11-16

Altered sensory experience in early life often leads to remarkable adaptations so that humans and animals can make the best use of the available information in a particular environment. By restricting visual input to a limited range of orientations in young animals, this investigation shows that stimulus selectivity, e.g., the sharpness of tuning of single neurons in the primary visual cortex, is modified to match a particular environment. Specifically, neurons tuned to an experienced orientation in orientation-restricted animals show sharper orientation tuning than neurons in normal animals, whereas the opposite was true for neurons tuned to non-experienced orientations. This sharpened tuning appears to be due to elongated receptive fields. Our results demonstrate that restricted sensory experiences can sculpt the supranormal functions of single neurons tailored for a particular environment. The above findings, in addition to the minimal population response to orientations close to the experienced one, agree with the predictions of a sparse coding hypothesis in which information is represented efficiently by a small number of activated neurons. This suggests that early brain areas adopt an efficient strategy for coding information even when animals are raised in a severely limited visual environment where sensory inputs have an unnatural statistical structure.

Supranormal orientation selectivity of visual neurons in orientation-restricted animals

PubMed Central

Sasaki, Kota S.; Kimura, Rui; Ninomiya, Taihei; Tabuchi, Yuka; Tanaka, Hiroki; Fukui, Masayuki; Asada, Yusuke C.; Arai, Toshiya; Inagaki, Mikio; Nakazono, Takayuki; Baba, Mika; Kato, Daisuke; Nishimoto, Shinji; Sanada, Takahisa M.; Tani, Toshiki; Imamura, Kazuyuki; Tanaka, Shigeru; Ohzawa, Izumi

2015-01-01

Altered sensory experience in early life often leads to remarkable adaptations so that humans and animals can make the best use of the available information in a particular environment. By restricting visual input to a limited range of orientations in young animals, this investigation shows that stimulus selectivity, e.g., the sharpness of tuning of single neurons in the primary visual cortex, is modified to match a particular environment. Specifically, neurons tuned to an experienced orientation in orientation-restricted animals show sharper orientation tuning than neurons in normal animals, whereas the opposite was true for neurons tuned to non-experienced orientations. This sharpened tuning appears to be due to elongated receptive fields. Our results demonstrate that restricted sensory experiences can sculpt the supranormal functions of single neurons tailored for a particular environment. The above findings, in addition to the minimal population response to orientations close to the experienced one, agree with the predictions of a sparse coding hypothesis in which information is represented efficiently by a small number of activated neurons. This suggests that early brain areas adopt an efficient strategy for coding information even when animals are raised in a severely limited visual environment where sensory inputs have an unnatural statistical structure. PMID:26567927

More than blindsight: Case report of a child with extraordinary visual capacity following perinatal bilateral occipital lobe injury.

PubMed

Mundinano, Inaki-Carril; Chen, Juan; de Souza, Mitchell; Sarossy, Marc G; Joanisse, Marc F; Goodale, Melvyn A; Bourne, James A

2017-11-13

Injury to the primary visual cortex (V1, striate cortex) and the geniculostriate pathway in adults results in cortical blindness, abolishing conscious visual perception. Early studies by Larry Weiskrantz and colleagues demonstrated that some patients with an occipital-lobe injury exhibited a degree of unconscious vision and visually-guided behaviour within the blind field. A more recent focus has been the observed phenomenon whereby early-life injury to V1 often results in the preservation of visual perception in both monkeys and humans. These findings initiated a concerted effort on multiple fronts, including nonhuman primate studies, to uncover the neural substrate/s of the spared conscious vision. In both adult and early-life cases of V1 injury, evidence suggests the involvement of the Middle Temporal area (MT) of the extrastriate visual cortex, which is an integral component area of the dorsal stream and is also associated with visually-guided behaviors. Because of the limited number of early-life V1 injury cases for humans, the outstanding question in the field is what secondary visual pathways are responsible for this extraordinary capacity? Here we report for the first time a case of a child (B.I.) who suffered a bilateral occipital-lobe injury in the first two weeks postnatally due to medium-chain acyl-Co-A dehydrogenase deficiency. At 6 years of age, B.I. underwent a battery of neurophysiological tests, as well as structural and diffusion MRI and ophthalmic examination at 7 years. Despite the extensive bilateral occipital cortical damage, B.I. has extensive conscious visual abilities, is not blind, and can use vision to navigate his environment. Furthermore, unlike blindsight patients, he can readily and consciously identify happy and neutral faces and colors, tasks associated with ventral stream processing. These findings suggest significant re-routing of visual information. To identify the putative visual pathway/s responsible for this ability, MRI tractography of secondary visual pathways connecting MT with the lateral geniculate nucleus (LGN) and the inferior pulvinar (PI) were analysed. Results revealed an increased PI-MT pathway in the left hemisphere, suggesting that this pulvinar relay could be the neural pathway affording the preserved visual capacity following an early-life lesion of V1. These findings corroborate anatomical evidence from monkeys showing an enhanced PI-MT pathway following an early-life lesion of V1, compared to adults. Copyright © 2017 Elsevier Ltd. All rights reserved.

The validity of visual acuity assessment using mobile technology devices in the primary care setting.

PubMed

O'Neill, Samuel; McAndrew, Darryl J

2016-04-01

The assessment of visual acuity is indicated in a number of clinical circumstances. It is commonly conducted through the use of a Snellen wall chart. Mobile technology developments and adoption rates by clinicians may potentially provide more convenient methods of assessing visual acuity. Limited data exist on the validity of these devices and applications. The objective of this study was to evaluate the assessment of distance visual acuity using mobile technology devices against the commonly used 3-metre Snellen chart in a primary care setting. A prospective quantitative comparative study was conducted at a regional medical practice. The visual acuity of 60 participants was assessed on a Snellen wall chart and two mobile technology devices (iPhone, iPad). Visual acuity intervals were converted to logarithm of minimum angle of resolution (logMAR) scores and subjected to intraclass correlation coefficient (ICC) assessment. The results show a high level of general agreement between testing modality (ICC 0.917 with a 95% confidence interval of 0.887-0.940). The high level of agreement of visual acuity results between the Snellen wall chart and both mobile technology devices suggests that clinicians can use this technology with confidence in the primary care setting.

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.

Spatial integration and cortical dynamics.

PubMed

Gilbert, C D; Das, A; Ito, M; Kapadia, M; Westheimer, G

1996-01-23

Cells in adult primary visual cortex are capable of integrating information over much larger portions of the visual field than was originally thought. Moreover, their receptive field properties can be altered by the context within which local features are presented and by changes in visual experience. The substrate for both spatial integration and cortical plasticity is likely to be found in a plexus of long-range horizontal connections, formed by cortical pyramidal cells, which link cells within each cortical area over distances of 6-8 mm. The relationship between horizontal connections and cortical functional architecture suggests a role in visual segmentation and spatial integration. The distribution of lateral interactions within striate cortex was visualized with optical recording, and their functional consequences were explored by using comparable stimuli in human psychophysical experiments and in recordings from alert monkeys. They may represent the substrate for perceptual phenomena such as illusory contours, surface fill-in, and contour saliency. The dynamic nature of receptive field properties and cortical architecture has been seen over time scales ranging from seconds to months. One can induce a remapping of the topography of visual cortex by making focal binocular retinal lesions. Shorter-term plasticity of cortical receptive fields was observed following brief periods of visual stimulation. The mechanisms involved entailed, for the short-term changes, altering the effectiveness of existing cortical connections, and for the long-term changes, sprouting of axon collaterals and synaptogenesis. The mutability of cortical function implies a continual process of calibration and normalization of the perception of visual attributes that is dependent on sensory experience throughout adulthood and might further represent the mechanism of perceptual learning.

Theories of Visual Rhetoric: Looking at the Human Genome.

ERIC Educational Resources Information Center

Rosner, Mary

2001-01-01

Considers how visuals are constructions that are products of a writer's interpretation with its own "power-laden agenda." Reviews the current approach taken by composition scholars, surveys richer interdisciplinary work on visuals, and (by using visuals connected with the Human Genome Project) models an analysis of visuals as rhetoric.…

A methodology for coupling a visual enhancement device to human visual attention

NASA Astrophysics Data System (ADS)

Todorovic, Aleksandar; Black, John A., Jr.; Panchanathan, Sethuraman

2009-02-01

The Human Variation Model views disability as simply "an extension of the natural physical, social, and cultural variability of mankind." Given this human variation, it can be difficult to distinguish between a prosthetic device such as a pair of glasses (which extends limited visual abilities into the "normal" range) and a visual enhancement device such as a pair of binoculars (which extends visual abilities beyond the "normal" range). Indeed, there is no inherent reason why the design of visual prosthetic devices should be limited to just providing "normal" vision. One obvious enhancement to human vision would be the ability to visually "zoom" in on objects that are of particular interest to the viewer. Indeed, it could be argued that humans already have a limited zoom capability, which is provided by their highresolution foveal vision. However, humans still find additional zooming useful, as evidenced by their purchases of binoculars equipped with mechanized zoom features. The fact that these zoom features are manually controlled raises two questions: (1) Could a visual enhancement device be developed to monitor attention and control visual zoom automatically? (2) If such a device were developed, would its use be experienced by users as a simple extension of their natural vision? This paper details the results of work with two research platforms called the Remote Visual Explorer (ReVEx) and the Interactive Visual Explorer (InVEx) that were developed specifically to answer these two questions.

Modern Scientific Visualization is more than Just Pretty Pictures

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

Bethel, E Wes; Rubel, Oliver; Wu, Kesheng

2008-12-05

While the primary product of scientific visualization is images and movies, its primary objective is really scientific insight. Too often, the focus of visualization research is on the product, not the mission. This paper presents two case studies, both that appear in previous publications, that focus on using visualization technology to produce insight. The first applies"Query-Driven Visualization" concepts to laser wakefield simulation data to help identify and analyze the process of beam formation. The second uses topological analysis to provide a quantitative basis for (i) understanding the mixing process in hydrodynamic simulations, and (ii) performing comparative analysis of data frommore » two different types of simulations that model hydrodynamic instability.« less

Preliminary investigation of visual attention to human figures in photographs: potential considerations for the design of aided AAC visual scene displays.

PubMed

Wilkinson, Krista M; Light, Janice

2011-12-01

Many individuals with complex communication needs may benefit from visual aided augmentative and alternative communication systems. In visual scene displays (VSDs), language concepts are embedded into a photograph of a naturalistic event. Humans play a central role in communication development and might be important elements in VSDs. However, many VSDs omit human figures. In this study, the authors sought to describe the distribution of visual attention to humans in naturalistic scenes as compared with other elements. Nineteen college students observed 8 photographs in which a human figure appeared near 1 or more items that might be expected to compete for visual attention (such as a Christmas tree or a table loaded with food). Eye-tracking technology allowed precise recording of participants' gaze. The fixation duration over a 7-s viewing period and latency to view elements in the photograph were measured. Participants fixated on the human figures more rapidly and for longer than expected based on the size of these figures, regardless of the other elements in the scene. Human figures attract attention in a photograph even when presented alongside other attractive distracters. Results suggest that humans may be a powerful means to attract visual attention to key elements in VSDs.

Information visualization: Beyond traditional engineering

NASA Technical Reports Server (NTRS)

Thomas, James J.

1995-01-01

This presentation addresses a different aspect of the human-computer interface; specifically the human-information interface. This interface will be dominated by an emerging technology called Information Visualization (IV). IV goes beyond the traditional views of computer graphics, CADS, and enables new approaches for engineering. IV specifically must visualize text, documents, sound, images, and video in such a way that the human can rapidly interact with and understand the content structure of information entities. IV is the interactive visual interface between humans and their information resources.

Basic Instinct Undressed: Early Spatiotemporal Processing for Primary Sexual Characteristics

PubMed Central

Legrand, Lore B.; Del Zotto, Marzia; Tyrand, Rémi; Pegna, Alan J.

2013-01-01

This study investigates the spatiotemporal dynamics associated with conscious and non-conscious processing of naked and dressed human bodies. To this effect, stimuli of naked men and women with visible primary sexual characteristics, as well as dressed bodies, were presented to 20 heterosexual male and female participants while acquiring high resolution EEG data. The stimuli were either consciously detectable (supraliminal presentations) or were rendered non-conscious through backward masking (subliminal presentations). The N1 event-related potential component was significantly enhanced in participants when they viewed naked compared to dressed bodies under supraliminal viewing conditions. More importantly, naked bodies of the opposite sex produced a significantly greater N1 component compared to dressed bodies during subliminal presentations, when participants were not aware of the stimulus presented. A source localization algorithm computed on the N1 showed that the response for naked bodies in the supraliminal viewing condition was stronger in body processing areas, primary visual areas and additional structures related to emotion processing. By contrast, in the subliminal viewing condition, only visual and body processing areas were found to be activated. These results suggest that naked bodies and primary sexual characteristics are processed early in time (i.e., <200 ms) and activate key brain structures even when they are not consciously detected. It appears that, similarly to what has been reported for emotional faces, sexual features benefit from automatic and rapid processing, most likely due to their high relevance for the individual and their importance for the species in terms of reproductive success. PMID:23894532

Visual Imagery without Visual Perception?

ERIC Educational Resources Information Center

Bertolo, Helder

2005-01-01

The question regarding visual imagery and visual perception remain an open issue. Many studies have tried to understand if the two processes share the same mechanisms or if they are independent, using different neural substrates. Most research has been directed towards the need of activation of primary visual areas during imagery. Here we review…

Primary Intracranial Choriocarcinoma Located in the Suprasellar Region

PubMed Central

Li, Xiuli; Murayama, Kazuhiro; Watanabe, Ayumi; Abe, Masato; Toyama, Hiroshi

2016-01-01

A 10 year old girl was admitted to our hospital due to headache, nausea, and weight loss for about half a year. She also had visual field disorders. Suprasellar tumor was found by X-ray computed tomography, and magnetic resonance imaging showed a ring-like lobulated enhanced mass with hemorrhage and necrosis. Biopsy of this lesion showed primary intracranial choriocarcinoma on histopathological examination. The serum human chorionic gonadotropin (hCG) level was measured after the biopsy and was elevated at 71,298.2 IU/L. The patient died due to hydrocephalus caused by an increase in the size of the tumor with a larger amount of hemorrhage than the preoperative features. If young patients present with a suprasellar lobulated mass with hemorrhage, the serum hCG level should be measured before operation. PMID:27499824

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.

Correspondence of presaccadic activity in the monkey primary visual cortex with saccadic eye movements

PubMed Central

Supèr, Hans; van der Togt, Chris; Spekreijse, Henk; Lamme, Victor A. F.

2004-01-01

We continuously scan the visual world via rapid or saccadic eye movements. Such eye movements are guided by visual information, and thus the oculomotor structures that determine when and where to look need visual information to control the eye movements. To know whether visual areas contain activity that may contribute to the control of eye movements, we recorded neural responses in the visual cortex of monkeys engaged in a delayed figure-ground detection task and analyzed the activity during the period of oculomotor preparation. We show that ≈100 ms before the onset of visually and memory-guided saccades neural activity in V1 becomes stronger where the strongest presaccadic responses are found at the location of the saccade target. In addition, in memory-guided saccades the strength of presaccadic activity shows a correlation with the onset of the saccade. These findings indicate that the primary visual cortex contains saccade-related responses and participates in visually guided oculomotor behavior. PMID:14970334

Figure-ground activity in primary visual cortex (V1) of the monkey matches the speed of behavioral response.

PubMed

Supèr, Hans; Spekreijse, Henk; Lamme, Victor A F

2003-06-26

To look at an object its position in the visual scene has to be localized and subsequently appropriate oculo-motor behavior needs to be initiated. This kind of behavior is largely controlled by the cortical executive system, such as the frontal eye field. In this report, we analyzed neural activity in the visual cortex in relation to oculo-motor behavior. We show that in a figure-ground detection task, the strength of late modulated activity in the primary visual cortex correlates with the saccade latency. We propose that this may indicate that the variability of reaction times in the detection of a visual stimulus is reflected in low-level visual areas as well as in high-level areas.

Epicenters of dynamic connectivity in the adaptation of the ventral visual system.

PubMed

Prčkovska, Vesna; Huijbers, Willem; Schultz, Aaron; Ortiz-Teran, Laura; Peña-Gomez, Cleofe; Villoslada, Pablo; Johnson, Keith; Sperling, Reisa; Sepulcre, Jorge

2017-04-01

Neuronal responses adapt to familiar and repeated sensory stimuli. Enhanced synchrony across wide brain systems has been postulated as a potential mechanism for this adaptation phenomenon. Here, we used recently developed graph theory methods to investigate hidden connectivity features of dynamic synchrony changes during a visual repetition paradigm. Particularly, we focused on strength connectivity changes occurring at local and distant brain neighborhoods. We found that connectivity reorganization in visual modal cortex-such as local suppressed connectivity in primary visual areas and distant suppressed connectivity in fusiform areas-is accompanied by enhanced local and distant connectivity in higher cognitive processing areas in multimodal and association cortex. Moreover, we found a shift of the dynamic functional connections from primary-visual-fusiform to primary-multimodal/association cortex. These findings suggest that repetition-suppression is made possible by reorganization of functional connectivity that enables communication between low- and high-order areas. Hum Brain Mapp 38:1965-1976, 2017. © 2017 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Long-Lasting Enhancement of Visual Perception with Repetitive Noninvasive Transcranial Direct Current Stimulation

PubMed Central

Behrens, Janina R.; Kraft, Antje; Irlbacher, Kerstin; Gerhardt, Holger; Olma, Manuel C.; Brandt, Stephan A.

2017-01-01

Understanding processes performed by an intact visual cortex as the basis for developing methods that enhance or restore visual perception is of great interest to both researchers and medical practitioners. Here, we explore whether contrast sensitivity, a main function of the primary visual cortex (V1), can be improved in healthy subjects by repetitive, noninvasive anodal transcranial direct current stimulation (tDCS). Contrast perception was measured via threshold perimetry directly before and after intervention (tDCS or sham stimulation) on each day over 5 consecutive days (24 subjects, double-blind study). tDCS improved contrast sensitivity from the second day onwards, with significant effects lasting 24 h. After the last stimulation on day 5, the anodal group showed a significantly greater improvement in contrast perception than the sham group (23 vs. 5%). We found significant long-term effects in only the central 2–4° of the visual field 4 weeks after the last stimulation. We suspect a combination of two factors contributes to these lasting effects. First, the V1 area that represents the central retina was located closer to the polarization electrode, resulting in higher current density. Second, the central visual field is represented by a larger cortical area relative to the peripheral visual field (cortical magnification). This is the first study showing that tDCS over V1 enhances contrast perception in healthy subjects for several weeks. This study contributes to the investigation of the causal relationship between the external modulation of neuronal membrane potential and behavior (in our case, visual perception). Because the vast majority of human studies only show temporary effects after single tDCS sessions targeting the visual system, our study underpins the potential for lasting effects of repetitive tDCS-induced modulation of neuronal excitability. PMID:28860969

Enhanced Visual Cortical Activation for Emotional Stimuli is Preserved in Patients with Unilateral Amygdala Resection

PubMed Central

Edmiston, E. Kale; McHugo, Maureen; Dukic, Mildred S.; Smith, Stephen D.; Abou-Khalil, Bassel; Eggers, Erica

2013-01-01

Emotionally arousing pictures induce increased activation of visual pathways relative to emotionally neutral images. A predominant model for the preferential processing and attention to emotional stimuli posits that the amygdala modulates sensory pathways through its projections to visual cortices. However, recent behavioral studies have found intact perceptual facilitation of emotional stimuli in individuals with amygdala damage. To determine the importance of the amygdala to modulations in visual processing, we used functional magnetic resonance imaging to examine visual cortical blood oxygenation level-dependent (BOLD) signal in response to emotionally salient and neutral images in a sample of human patients with unilateral medial temporal lobe resection that included the amygdala. Adults with right (n = 13) or left (n = 5) medial temporal lobe resections were compared with demographically matched healthy control participants (n = 16). In the control participants, both aversive and erotic images produced robust BOLD signal increases in bilateral primary and secondary visual cortices relative to neutral images. Similarly, all patients with amygdala resections showed enhanced visual cortical activations to erotic images both ipsilateral and contralateral to the lesion site. All but one of the amygdala resection patients showed similar enhancements to aversive stimuli and there were no significant group differences in visual cortex BOLD responses in patients compared with controls for either aversive or erotic images. Our results indicate that neither the right nor left amygdala is necessary for the heightened visual cortex BOLD responses observed during emotional stimulus presentation. These data challenge an amygdalo-centric model of emotional modulation and suggest that non-amygdalar processes contribute to the emotional modulation of sensory pathways. PMID:23825407

Improving Image Segmentation with Adaptive, Recurrent, Spiking Neural Network Models of the Primary Visual Cortex

DTIC Science & Technology

2017-05-19

Vijay Singh, Martin Tchernookov, Rebecca Butterfield, Ilya Nemenman, Rongrong Ji. Director Field Model of the Primary Visual Cortex for Contour...FTE Equivalent: Total Number: DISCIPLINE Vijay Singh 40 Physics 0.40 1 PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: Martin Tchernookov 0.20

High frequency oscillations are associated with cognitive processing in human recognition memory.

PubMed

Kucewicz, Michal T; Cimbalnik, Jan; Matsumoto, Joseph Y; Brinkmann, Benjamin H; Bower, Mark R; Vasoli, Vincent; Sulc, Vlastimil; Meyer, Fred; Marsh, W R; Stead, S M; Worrell, Gregory A

2014-08-01

High frequency oscillations are associated with normal brain function, but also increasingly recognized as potential biomarkers of the epileptogenic brain. Their role in human cognition has been predominantly studied in classical gamma frequencies (30-100 Hz), which reflect neuronal network coordination involved in attention, learning and memory. Invasive brain recordings in animals and humans demonstrate that physiological oscillations extend beyond the gamma frequency range, but their function in human cognitive processing has not been fully elucidated. Here we investigate high frequency oscillations spanning the high gamma (50-125 Hz), ripple (125-250 Hz) and fast ripple (250-500 Hz) frequency bands using intracranial recordings from 12 patients (five males and seven females, age 21-63 years) during memory encoding and recall of a series of affectively charged images. Presentation of the images induced high frequency oscillations in all three studied bands within the primary visual, limbic and higher order cortical regions in a sequence consistent with the visual processing stream. These induced oscillations were detected on individual electrodes localized in the amygdala, hippocampus and specific neocortical areas, revealing discrete oscillations of characteristic frequency, duration and latency from image presentation. Memory encoding and recall significantly modulated the number of induced high gamma, ripple and fast ripple detections in the studied structures, which was greater in the primary sensory areas during the encoding (Wilcoxon rank sum test, P = 0.002) and in the higher-order cortical association areas during the recall (Wilcoxon rank sum test, P = 0.001) of memorized images. Furthermore, the induced high gamma, ripple and fast ripple responses discriminated the encoded and the affectively charged images. In summary, our results show that high frequency oscillations, spanning a wide range of frequencies, are associated with memory processing and generated along distributed cortical and limbic brain regions. These findings support an important role for fast network synchronization in human cognition and extend our understanding of normal physiological brain activity during memory processing. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Preparation for the Implantation of an Intracortical Visual Prosthesis in a Human

DTIC Science & Technology

2014-10-01

Intracortical Visual Prosthesis in a Human PRINCIPAL INVESTIGATOR: Philip R Troyk, PhD... Prosthesis in a Human 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-1-0394 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Philip R Troyk...visual prosthesis (ICVP) for testing in a human. No human trial testing of the prosthesis will occur under the funded work. Preparatory tasks include

Recordings from human myenteric neurons using voltage-sensitive dyes.

PubMed

Vignali, Sheila; Peter, Nadine; Ceyhan, Güralp; Demir, Ihsan Ekin; Zeller, Florian; Senseman, David; Michel, Klaus; Schemann, Michael

2010-10-15

Voltage-sensitive dye (VSD) imaging became a powerful tool to detect neural activity in the enteric nervous system, including its routine use in submucous neurons in freshly dissected human tissue. However, VSD imaging of human myenteric neurons remained a challenge because of limited visibility of the ganglia and dye accessibility. We describe a protocol to apply VSD for recordings of human myenteric neurons in freshly dissected tissue and myenteric neurons in primary cultures. VSD imaging of guinea-pig myenteric neurons was used for reference. Electrical stimulation of interganglionic fiber tracts and exogenous application of nicotine or elevated KCl solution was used to evoke action potentials. Bath application of the VSDs Annine-6Plus, Di-4-ANEPPS, Di-8-ANEPPQ, Di-4-ANEPPDHQ or Di-8-ANEPPS revealed no neural signals in human tissue although most of these VSD worked in guinea-pig tissue. Unlike methylene blue and FM1-43, 4-Di-2-ASP did not influence spike discharge and was used in human tissue to visualize myenteric ganglia as a prerequisite for targeted intraganglionic VSD application. Of all VSDs, only intraganglionic injection of Di-8-ANEPPS by a volume controlled injector revealed neuronal signals in human tissue. Signal-to-noise ratio increased by addition of dipicrylamine to Di-8-ANEPPS (0.98±0.16 vs. 2.4±0.62). Establishing VSD imaging in primary cultures of human myenteric neurons led to a further improvement of signal-to-noise ratio. This allowed us to routinely record spike discharge after nicotine application. The described protocol enabled reliable VSD recordings from human myenteric neurons but may also be relevant for the use of other fluorescent dyes in human tissues. Copyright © 2010 Elsevier B.V. All rights reserved.

Frequency-band signatures of visual responses to naturalistic input in ferret primary visual cortex during free viewing.

PubMed

Sellers, Kristin K; Bennett, Davis V; Fröhlich, Flavio

2015-02-19

Neuronal firing responses in visual cortex reflect the statistics of visual input and emerge from the interaction with endogenous network dynamics. Artificial visual stimuli presented to animals in which the network dynamics were constrained by anesthetic agents or trained behavioral tasks have provided fundamental understanding of how individual neurons in primary visual cortex respond to input. In contrast, very little is known about the mesoscale network dynamics and their relationship to microscopic spiking activity in the awake animal during free viewing of naturalistic visual input. To address this gap in knowledge, we recorded local field potential (LFP) and multiunit activity (MUA) simultaneously in all layers of primary visual cortex (V1) of awake, freely viewing ferrets presented with naturalistic visual input (nature movie clips). We found that naturalistic visual stimuli modulated the entire oscillation spectrum; low frequency oscillations were mostly suppressed whereas higher frequency oscillations were enhanced. In average across all cortical layers, stimulus-induced change in delta and alpha power negatively correlated with the MUA responses, whereas sensory-evoked increases in gamma power positively correlated with MUA responses. The time-course of the band-limited power in these frequency bands provided evidence for a model in which naturalistic visual input switched V1 between two distinct, endogenously present activity states defined by the power of low (delta, alpha) and high (gamma) frequency oscillatory activity. Therefore, the two mesoscale activity states delineated in this study may define the degree of engagement of the circuit with the processing of sensory input. Copyright © 2014 Elsevier B.V. All rights reserved.

Frequency spectrum might act as communication code between retina and visual cortex I

PubMed Central

Yang, Xu; Gong, Bo; Lu, Jian-Wei

2015-01-01

AIM To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1). METHODS Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG) and pattern visually evoked potential (PVEP) and fast Fourier transform has been used to analyze the frequency components of those signals. RESULTS The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. CONCLUSION The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1. PMID:26682156

Visual Disability Among Juvenile Open-angle Glaucoma Patients.

PubMed

Gupta, Viney; Ganesan, Vaitheeswaran L; Kumar, Sandip; Chaurasia, Abadh K; Malhotra, Sumit; Gupta, Shikha

2018-04-01

Juvenile onset primary open-angle glaucoma (JOAG) unlike adult onset primary open-angle glaucoma presents with high intraocular pressure and diffuse visual field loss, which if left untreated leads to severe visual disability. The study aimed to evaluate the extent of visual disability among JOAG patients presenting to a tertiary eye care facility. Visual acuity and perimetry records of unrelated JOAG patients presenting to our Glaucoma facility were analyzed. Low vision and blindness was categorized by the WHO criteria and percentage impairment was calculated as per the guidelines provided by the American Medical Association (AMA). Fifty-two (15%) of the 348 JOAG patients were bilaterally blind at presentation and 32 (9%) had low vision according to WHO criteria. Ninety JOAG patients (26%) had a visual impairment of 75% or more. Visual disability at presentation among JOAG patients is high. This entails a huge economic burden, given their young age and associated social responsibilities.

Frequency spectrum might act as communication code between retina and visual cortex I.

PubMed

Yang, Xu; Gong, Bo; Lu, Jian-Wei

2015-01-01

To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1). Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG) and pattern visually evoked potential (PVEP) and fast Fourier transform has been used to analyze the frequency components of those signals. The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1.

Human Computation in Visualization: Using Purpose Driven Games for Robust Evaluation of Visualization Algorithms.

PubMed

Ahmed, N; Zheng, Ziyi; Mueller, K

2012-12-01

Due to the inherent characteristics of the visualization process, most of the problems in this field have strong ties with human cognition and perception. This makes the human brain and sensory system the only truly appropriate evaluation platform for evaluating and fine-tuning a new visualization method or paradigm. However, getting humans to volunteer for these purposes has always been a significant obstacle, and thus this phase of the development process has traditionally formed a bottleneck, slowing down progress in visualization research. We propose to take advantage of the newly emerging field of Human Computation (HC) to overcome these challenges. HC promotes the idea that rather than considering humans as users of the computational system, they can be made part of a hybrid computational loop consisting of traditional computation resources and the human brain and sensory system. This approach is particularly successful in cases where part of the computational problem is considered intractable using known computer algorithms but is trivial to common sense human knowledge. In this paper, we focus on HC from the perspective of solving visualization problems and also outline a framework by which humans can be easily seduced to volunteer their HC resources. We introduce a purpose-driven game titled "Disguise" which serves as a prototypical example for how the evaluation of visualization algorithms can be mapped into a fun and addicting activity, allowing this task to be accomplished in an extensive yet cost effective way. Finally, we sketch out a framework that transcends from the pure evaluation of existing visualization methods to the design of a new one.

Bayesian integration of position and orientation cues in perception of biological and non-biological forms.

PubMed

Thurman, Steven M; Lu, Hongjing

2014-01-01

Visual form analysis is fundamental to shape perception and likely plays a central role in perception of more complex dynamic shapes, such as moving objects or biological motion. Two primary form-based cues serve to represent the overall shape of an object: the spatial position and the orientation of locations along the boundary of the object. However, it is unclear how the visual system integrates these two sources of information in dynamic form analysis, and in particular how the brain resolves ambiguities due to sensory uncertainty and/or cue conflict. In the current study, we created animations of sparsely-sampled dynamic objects (human walkers or rotating squares) comprised of oriented Gabor patches in which orientation could either coincide or conflict with information provided by position cues. When the cues were incongruent, we found a characteristic trade-off between position and orientation information whereby position cues increasingly dominated perception as the relative uncertainty of orientation increased and vice versa. Furthermore, we found no evidence for differences in the visual processing of biological and non-biological objects, casting doubt on the claim that biological motion may be specialized in the human brain, at least in specific terms of form analysis. To explain these behavioral results quantitatively, we adopt a probabilistic template-matching model that uses Bayesian inference within local modules to estimate object shape separately from either spatial position or orientation signals. The outputs of the two modules are integrated with weights that reflect individual estimates of subjective cue reliability, and integrated over time to produce a decision about the perceived dynamics of the input data. Results of this model provided a close fit to the behavioral data, suggesting a mechanism in the human visual system that approximates rational Bayesian inference to integrate position and orientation signals in dynamic form analysis.

Look, Snap, See: Visual Literacy through the Camera.

ERIC Educational Resources Information Center

Spoerner, Thomas M.

1981-01-01

Activities involving photographs stimulate visual perceptual awareness. Children understand visual stimuli before having verbal capacity to deal with the world. Vision becomes the primary means for learning, understanding, and adjusting to the environment. Photography can provide an effective avenue to visual literacy. (Author)

Preparation for the Implantation of an Intracortical Visual Prosthesis in a Human

DTIC Science & Technology

2013-10-01

Intracortical Visual Prosthesis in a Human PRINCIPAL INVESTIGATOR: Philip R Troyk, PhD... Prosthesis in a Human 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-1-0394 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Philip R Troyk, PhD...to prepare an intracortical visual prosthesis (ICVP) for testing in a human. No human trial testing of the prosthesis will occur under the funded

Visual Culture, Art History and the Humanities

ERIC Educational Resources Information Center

Castaneda, Ivan

2009-01-01

This essay will discuss the need for the humanities to address visual culture studies as part of its interdisciplinary mission in today's university. Although mostly unnoticed in recent debates in the humanities over historical and theoretical frameworks, the relatively new field of visual culture has emerged as a corrective to a growing…

Primary Pterygium in a 7-Year-Old Boy: A Report of a Rare Case and Dilemma of its Management

PubMed Central

Noor, Raja Azmi Mohd

2003-01-01

Primary pterygium in children is uncommon but is associated with severe visual problems. Astigmatism is the main visual problem caused by pterygium. Significant amounts of astigmatism occur long before a pterygium encroaches the visual axis. Early surgical intervention is safe and effective. It is associated with significant visual improvement in outcome. This is a case report on seven-year-old Malay boy who presented with a growth over nasal aspect of the right eye of 1 year duration. His right eye visual acuity is affected up to 6/12. The dilemma pased to early surgical interview is the high rate of recurrancean the young age group. This problem is highlighted in this case report. PMID:23386804

Primary pterygium in a 7-year-old boy: a report of a rare case and dilemma of its management.

PubMed

Noor, Raja Azmi Mohd

2003-07-01

Primary pterygium in children is uncommon but is associated with severe visual problems. Astigmatism is the main visual problem caused by pterygium. Significant amounts of astigmatism occur long before a pterygium encroaches the visual axis. Early surgical intervention is safe and effective. It is associated with significant visual improvement in outcome. This is a case report on seven-year-old Malay boy who presented with a growth over nasal aspect of the right eye of 1 year duration. His right eye visual acuity is affected up to 6/12. The dilemma pased to early surgical interview is the high rate of recurrancean the young age group. This problem is highlighted in this case report.

Localized 1H NMR measurement of glucose consumption in the human brain during visual stimulation.

PubMed Central

Chen, W; Novotny, E J; Zhu, X H; Rothman, D L; Shulman, R G

1993-01-01

Spatially localized 1H NMR spectroscopy has been applied to measure changes in brain glucose concentration during 8-Hz photic stimulation. NMR spectroscopic measurements were made in a 12-cm3 volume centered on the calcarine fissure and encompassing the primary visual cortex. The average maximum change in glucose levels was 0.34 mumol.g-1 (n = 5) at 15 min; glucose level had turned toward resting level at 25 min. The glucose change was used to calculate the increase of glucose cerebral metabolic rate in the visual cortex region for individual subjects by using the Michaelis-Menten model of glucose transport on the assumption of constant transport kinetics. The glucose cerebral metabolic rate was calculated to increase over the nonstimulated rate by 22% during the first 15 min of photic stimulation. A model in which the glucose metabolic rate gradually decreases during stimulation was proposed as a possible explanation for the recovery of brain glucose and previously measured lactate concentrations to prestimulus values after 15 min. Images Fig. 1 PMID:8234332

Three-dimensional Talairach-Tournoux brain atlas

NASA Astrophysics Data System (ADS)

Fang, Anthony; Nowinski, Wieslaw L.; Nguyen, Bonnie T.; Bryan, R. Nick

1995-04-01

The Talairach-Tournoux Stereotaxic Atlas of the human brain is a frequently consulted resource in stereotaxic neurosurgery and computer-based neuroradiology. Its primary application lies in the 2-D analysis and interpretation of neurological images. However, for the purpose of the analysis and visualization of shapes and forms, accurate mensuration of volumes, or 3-D models matching, a 3-D representation of the atlas is essential. This paper proposes and describes, along with its difficulties, a 3-D geometric extension of the atlas. We introduce a `zero-potential' surface smoothing technique, along with a space-dependent convolution kernel and space-dependent normalization. The mesh-based atlas structures are hierarchically organized, and anatomically conform to the original atlas. Structures and their constituents can be independently selected and manipulated in real-time within an integrated system. The extended atlas may be navigated by itself, or interactively registered with patient data with the proportional grid system (piecewise linear) transformation. Visualization of the geometric atlas along with patient data gives a remarkable visual `feel' of the biological structures, not usually perceivable to the untrained eyes in conventional 2-D atlas to image analysis.

Human blindsight is mediated by an intact geniculo-extrastriate pathway

PubMed Central

Ajina, Sara; Pestilli, Franco; Rokem, Ariel; Kennard, Christopher; Bridge, Holly

2015-01-01

Although damage to the primary visual cortex (V1) causes hemianopia, many patients retain some residual vision; known as blindsight. We show that blindsight may be facilitated by an intact white-matter pathway between the lateral geniculate nucleus and motion area hMT+. Visual psychophysics, diffusion-weighted magnetic resonance imaging and fibre tractography were applied in 17 patients with V1 damage acquired during adulthood and 9 age-matched controls. Individuals with V1 damage were subdivided into blindsight positive (preserved residual vision) and negative (no residual vision) according to psychophysical performance. All blindsight positive individuals showed intact geniculo-hMT+ pathways, while this pathway was significantly impaired or not measurable in blindsight negative individuals. Two white matter pathways previously implicated in blindsight: (i) superior colliculus to hMT+ and (ii) between hMT+ in each hemisphere were not consistently present in blindsight positive cases. Understanding the visual pathways crucial for residual vision may direct future rehabilitation strategies for hemianopia patients. DOI: http://dx.doi.org/10.7554/eLife.08935.001 PMID:26485034

Parallel pathways from whisker and visual sensory cortices to distinct frontal regions of mouse neocortex

PubMed Central

Sreenivasan, Varun; Kyriakatos, Alexandros; Mateo, Celine; Jaeger, Dieter; Petersen, Carl C.H.

2016-01-01

Abstract. The spatial organization of mouse frontal cortex is poorly understood. Here, we used voltage-sensitive dye to image electrical activity in the dorsal cortex of awake head-restrained mice. Whisker-deflection evoked the earliest sensory response in a localized region of primary somatosensory cortex and visual stimulation evoked the earliest responses in a localized region of primary visual cortex. Over the next milliseconds, the initial sensory response spread within the respective primary sensory cortex and into the surrounding higher order sensory cortices. In addition, secondary hotspots in the frontal cortex were evoked by whisker and visual stimulation, with the frontal hotspot for whisker deflection being more anterior and lateral compared to the frontal hotspot evoked by visual stimulation. Investigating axonal projections, we found that the somatosensory whisker cortex and the visual cortex directly innervated frontal cortex, with visual cortex axons innervating a region medial and posterior to the innervation from somatosensory cortex, consistent with the location of sensory responses in frontal cortex. In turn, the axonal outputs of these two frontal cortical areas innervate distinct regions of striatum, superior colliculus, and brainstem. Sensory input, therefore, appears to map onto modality-specific regions of frontal cortex, perhaps participating in distinct sensorimotor transformations, and directing distinct motor outputs. PMID:27921067

In Situ Proximity Ligation Assay Reveals Co-Localization of Alpha-Synuclein and SNARE Proteins in Murine Primary Neurons.

PubMed

Almandoz-Gil, Leire; Persson, Emma; Lindström, Veronica; Ingelsson, Martin; Erlandsson, Anna; Bergström, Joakim

2018-01-01

The aggregation of alpha-synuclein (αSyn) is the pathological hallmark of Parkinson's disease, dementia with Lewy bodies and related neurological disorders. However, the physiological function of the protein and how this function relates to its pathological effects remain poorly understood. One of the proposed roles of αSyn is to promote the soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex assembly by binding to VAMP-2. The objective of this study was to visualize the co-localization between αSyn and the SNARE proteins (VAMP-2, SNAP-25, and syntaxin-1) for the first time using in situ proximity ligation assay (PLA). Cortical primary neurons were cultured from either non-transgenic or transgenic mice expressing human αSyn with the A30P mutation under the Thy-1 promoter. With an antibody recognizing both mouse and human αSyn, a PLA signal indicating close proximity between αSyn and the three SNARE proteins was observed both in the soma and throughout the processes. No differences in the extent of PLA signals were seen between non-transgenic and transgenic neurons. With an antibody specific against human αSyn, the PLA signal was mostly located to the soma and was only present in a few cells. Taken together, in situ PLA is a method that can be used to investigate the co-localization of αSyn and the SNARE proteins in primary neuronal cultures.

Primary visual response (M100) delays in adolescents with FASD as measured with MEG.

PubMed

Coffman, Brian A; Kodituwakku, Piyadasa; Kodituwakku, Elizabeth L; Romero, Lucinda; Sharadamma, Nirupama Muniswamy; Stone, David; Stephen, Julia M

2013-11-01

Fetal alcohol spectrum disorders (FASD) are debilitating, with effects of prenatal alcohol exposure persisting into adolescence and adulthood. Complete characterization of FASD is crucial for the development of diagnostic tools and intervention techniques to decrease the high cost to individual families and society of this disorder. In this experiment, we investigated visual system deficits in adolescents (12-21 years) diagnosed with an FASD by measuring the latency of patients' primary visual M100 responses using MEG. We hypothesized that patients with FASD would demonstrate delayed primary visual responses compared to controls. M100 latencies were assessed both for FASD patients and age-matched healthy controls for stimuli presented at the fovea (central stimulus) and at the periphery (peripheral stimuli; left or right of the central stimulus) in a saccade task requiring participants to direct their attention and gaze to these stimuli. Source modeling was performed on visual responses to the central and peripheral stimuli and the latency of the first prominent peak (M100) in the occipital source timecourse was identified. The peak latency of the M100 responses were delayed in FASD patients for both stimulus types (central and peripheral), but the difference in latency of primary visual responses to central vs. peripheral stimuli was significant only in FASD patients, indicating that, while FASD patients' visual systems are impaired in general, this impairment is more pronounced in the periphery. These results suggest that basic sensory deficits in this population may contribute to sensorimotor integration deficits described previously in this disorder. Copyright © 2012 Wiley Periodicals, Inc.

The Human is the Loop: New Directions for Visual Analytics

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

Endert, Alexander; Hossain, Shahriar H.; Ramakrishnan, Naren

2014-01-28

Visual analytics is the science of marrying interactive visualizations and analytic algorithms to support exploratory knowledge discovery in large datasets. We argue for a shift from a ‘human in the loop’ philosophy for visual analytics to a ‘human is the loop’ viewpoint, where the focus is on recognizing analysts’ work processes, and seamlessly fitting analytics into that existing interactive process. We survey a range of projects that provide visual analytic support contextually in the sensemaking loop, and outline a research agenda along with future challenges.

Visual recovery in cortical blindness is limited by high internal noise

PubMed Central

Cavanaugh, Matthew R.; Zhang, Ruyuan; Melnick, Michael D.; Das, Anasuya; Roberts, Mariel; Tadin, Duje; Carrasco, Marisa; Huxlin, Krystel R.

2015-01-01

Damage to the primary visual cortex typically causes cortical blindness (CB) in the hemifield contralateral to the damaged hemisphere. Recent evidence indicates that visual training can partially reverse CB at trained locations. Whereas training induces near-complete recovery of coarse direction and orientation discriminations, deficits in fine motion processing remain. Here, we systematically disentangle components of the perceptual inefficiencies present in CB fields before and after coarse direction discrimination training. In seven human CB subjects, we measured threshold versus noise functions before and after coarse direction discrimination training in the blind field and at corresponding intact field locations. Threshold versus noise functions were analyzed within the framework of the linear amplifier model and the perceptual template model. Linear amplifier model analysis identified internal noise as a key factor differentiating motion processing across the tested areas, with visual training reducing internal noise in the blind field. Differences in internal noise also explained residual perceptual deficits at retrained locations. These findings were confirmed with perceptual template model analysis, which further revealed that the major residual deficits between retrained and intact field locations could be explained by differences in internal additive noise. There were no significant differences in multiplicative noise or the ability to process external noise. Together, these results highlight the critical role of altered internal noise processing in mediating training-induced visual recovery in CB fields, and may explain residual perceptual deficits relative to intact regions of the visual field. PMID:26389544

Common Visual Preference for Curved Contours in Humans and Great Apes.

PubMed

Munar, Enric; Gómez-Puerto, Gerardo; Call, Josep; Nadal, Marcos

2015-01-01

Among the visual preferences that guide many everyday activities and decisions, from consumer choices to social judgment, preference for curved over sharp-angled contours is commonly thought to have played an adaptive role throughout human evolution, favoring the avoidance of potentially harmful objects. However, because nonhuman primates also exhibit preferences for certain visual qualities, it is conceivable that humans' preference for curved contours is grounded on perceptual and cognitive mechanisms shared with extant nonhuman primate species. Here we aimed to determine whether nonhuman great apes and humans share a visual preference for curved over sharp-angled contours using a 2-alternative forced choice experimental paradigm under comparable conditions. Our results revealed that the human group and the great ape group indeed share a common preference for curved over sharp-angled contours, but that they differ in the manner and magnitude with which this preference is expressed behaviorally. These results suggest that humans' visual preference for curved objects evolved from earlier primate species' visual preferences, and that during this process it became stronger, but also more susceptible to the influence of higher cognitive processes and preference for other visual features.

Visually Evoked Spiking Evolves While Spontaneous Ongoing Dynamics Persist

PubMed Central

Huys, Raoul; Jirsa, Viktor K.; Darokhan, Ziauddin; Valentiniene, Sonata; Roland, Per E.

2016-01-01

Neurons in the primary visual cortex spontaneously spike even when there are no visual stimuli. It is unknown whether the spiking evoked by visual stimuli is just a modification of the spontaneous ongoing cortical spiking dynamics or whether the spontaneous spiking state disappears and is replaced by evoked spiking. This study of laminar recordings of spontaneous spiking and visually evoked spiking of neurons in the ferret primary visual cortex shows that the spiking dynamics does not change: the spontaneous spiking as well as evoked spiking is controlled by a stable and persisting fixed point attractor. Its existence guarantees that evoked spiking return to the spontaneous state. However, the spontaneous ongoing spiking state and the visual evoked spiking states are qualitatively different and are separated by a threshold (separatrix). The functional advantage of this organization is that it avoids the need for a system reorganization following visual stimulation, and impedes the transition of spontaneous spiking to evoked spiking and the propagation of spontaneous spiking from layer 4 to layers 2–3. PMID:26778982

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.

Isolated cortical visual loss with subtle brain MRI abnormalities in a case of hypoxic-ischemic encephalopathy.

PubMed

Margolin, Edward; Gujar, Sachin K; Trobe, Jonathan D

2007-12-01

A 16-year-old boy who was briefly asystolic and hypotensive after a motor vehicle accident complained of abnormal vision after recovering consciousness. Visual acuity was normal, but visual fields were severely constricted without clear hemianopic features. The ophthalmic examination was otherwise normal. Brain MRI performed 11 days after the accident showed no pertinent abnormalities. At 6 months after the event, brain MRI demonstrated brain volume loss in the primary visual cortex and no other abnormalities. One year later, visual fields remained severely constricted; neurologic examination, including formal neuropsychometric testing, was normal. This case emphasizes the fact that hypoxic-ischemic encephalopathy (HIE) may cause enduring damage limited to primary visual cortex and that the MRI abnormalities may be subtle. These phenomena should be recognized in the management of patients with HIE.

Synthesis maps: visual knowledge translation for the CanIMPACT clinical system and patient cancer journeys.

PubMed

Jones, P H; Shakdher, S; Singh, P

2017-04-01

Salient findings and interpretations from the canimpact clinical cancer research study are visually represented in two synthesis maps for the purpose of communicating an integrated presentation of the study to clinical cancer researchers and policymakers. Synthesis maps integrate evidence and expertise into a visual narrative for knowledge translation and communication. A clinical system synthesis map represents the current Canadian primary care and cancer practice systems, proposed as a visual knowledge translation from the mixed-methods canimpact study to inform Canadian clinical research, policy, and practice discourses. Two synthesis maps, drawn together from multiple canimpact investigations and sources, were required to articulate critical differences between the clinical system and patient perspectives. The synthesis map of Canada-wide clinical cancer systems illustrates the relationships between primary care and the full cancer continuum. A patient-centred map was developed to represent the cancer (and primary care) journeys as experienced by breast and colorectal cancer patients.

Space Suit Performance: Methods for Changing the Quality of Quantitative Data

NASA Technical Reports Server (NTRS)

Cowley, Matthew; Benson, Elizabeth; Rajulu, Sudhakar

2014-01-01

NASA is currently designing a new space suit capable of working in deep space and on Mars. Designing a suit is very difficult and often requires trade-offs between performance, cost, mass, and system complexity. To verify that new suits will enable astronauts to perform to their maximum capacity, prototype suits must be built and tested with human subjects. However, engineers and flight surgeons often have difficulty understanding and applying traditional representations of human data without training. To overcome these challenges, NASA is developing modern simulation and analysis techniques that focus on 3D visualization. Early understanding of actual performance early on in the design cycle is extremely advantageous to increase performance capabilities, reduce the risk of injury, and reduce costs. The primary objective of this project was to test modern simulation and analysis techniques for evaluating the performance of a human operating in extra-vehicular space suits.

Primary School Pupils' Response to Audio-Visual Learning Process in Port-Harcourt

ERIC Educational Resources Information Center

Olube, Friday K.

2015-01-01

The purpose of this study is to examine primary school children's response on the use of audio-visual learning processes--a case study of Chokhmah International Academy, Port-Harcourt (owned by Salvation Ministries). It looked at the elements that enhance pupils' response to educational television programmes and their hindrances to these…

Assistive Device Use in Visually Impaired Older Adults: Role of Control Beliefs

ERIC Educational Resources Information Center

Becker, Stefanie; Wahl, Hans-Werner; Schilling, Oliver; Burmedi, David

2005-01-01

Purpose: We investigate whether psychological control, conceptually framed within the life-span theory of control by Heckhausen and Schulz, drives assistive device use in visually impaired elders. In particular, we expect the two primary control modes differentiated in the life-span theory of control (i.e., selective primary and compensatory…

Higher Brain Functions Served by the Lowly Rodent Primary Visual Cortex

ERIC Educational Resources Information Center

Gavornik, Jeffrey P.; Bear, Mark F.

2014-01-01

It has been more than 50 years since the first description of ocular dominance plasticity--the profound modification of primary visual cortex (V1) following temporary monocular deprivation. This discovery immediately attracted the intense interest of neurobiologists focused on the general question of how experience and deprivation modify the brain…

fMRI-based Multivariate Pattern Analyses Reveal Imagery Modality and Imagery Content Specific Representations in Primary Somatosensory, Motor and Auditory Cortices.

PubMed

de Borst, Aline W; de Gelder, Beatrice

2017-08-01

Previous studies have shown that the early visual cortex contains content-specific representations of stimuli during visual imagery, and that these representational patterns of imagery content have a perceptual basis. To date, there is little evidence for the presence of a similar organization in the auditory and tactile domains. Using fMRI-based multivariate pattern analyses we showed that primary somatosensory, auditory, motor, and visual cortices are discriminative for imagery of touch versus sound. In the somatosensory, motor and visual cortices the imagery modality discriminative patterns were similar to perception modality discriminative patterns, suggesting that top-down modulations in these regions rely on similar neural representations as bottom-up perceptual processes. Moreover, we found evidence for content-specific representations of the stimuli during auditory imagery in the primary somatosensory and primary motor cortices. Both the imagined emotions and the imagined identities of the auditory stimuli could be successfully classified in these regions. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Investigation of Neural Strategies of Visual Search

NASA Technical Reports Server (NTRS)

Krauzlis, Richard J.

2003-01-01

The goal of this project was to measure how neurons in the superior colliculus (SC) change their activity during a visual search task. Specifically, we proposed to measure how the activity of these neurons was altered by the discriminability of visual targets and to test how these changes might predict the changes in the subjects performance. The primary rationale for this study was that understanding how the information encoded by these neurons constrains overall search performance would foster the development of better models of human performance. Work performed during the period supported by this grant has achieved these aims. First, we have recorded from neurons in the superior colliculus (SC) during a visual search task in which the difficulty of the task and the performance of the subject was systematically varied. The results from these single-neuron physiology experiments shows that prior to eye movement onset, the difference in activity across the ensemble of neurons reaches a fixed threshold value, reflecting the operation of a winner-take-all mechanism. Second, we have developed a model of eye movement decisions based on the principle of winner-take-all . The model incorporates the idea that the overt saccade choice reflects only one of the multiple saccades prepared during visual discrimination, consistent with our physiological data. The value of the model is that, unlike previous models, it is able to account for both the latency and the percent correct of saccade choices.

Residual attention guidance in blindsight monkeys watching complex natural scenes.

PubMed

Yoshida, Masatoshi; Itti, Laurent; Berg, David J; Ikeda, Takuro; Kato, Rikako; Takaura, Kana; White, Brian J; Munoz, Douglas P; Isa, Tadashi

2012-08-07

Patients with damage to primary visual cortex (V1) demonstrate residual performance on laboratory visual tasks despite denial of conscious seeing (blindsight) [1]. After a period of recovery, which suggests a role for plasticity [2], visual sensitivity higher than chance is observed in humans and monkeys for simple luminance-defined stimuli, grating stimuli, moving gratings, and other stimuli [3-7]. Some residual cognitive processes including bottom-up attention and spatial memory have also been demonstrated [8-10]. To date, little is known about blindsight with natural stimuli and spontaneous visual behavior. In particular, is orienting attention toward salient stimuli during free viewing still possible? We used a computational saliency map model to analyze spontaneous eye movements of monkeys with blindsight from unilateral ablation of V1. Despite general deficits in gaze allocation, monkeys were significantly attracted to salient stimuli. The contribution of orientation features to salience was nearly abolished, whereas contributions of motion, intensity, and color features were preserved. Control experiments employing laboratory stimuli confirmed the free-viewing finding that lesioned monkeys retained color sensitivity. Our results show that attention guidance over complex natural scenes is preserved in the absence of V1, thereby directly challenging theories and models that crucially depend on V1 to compute the low-level visual features that guide attention. Copyright © 2012 Elsevier Ltd. All rights reserved.

Interactions between attention, context and learning in primary visual cortex.

PubMed

Gilbert, C; Ito, M; Kapadia, M; Westheimer, G

2000-01-01

Attention in early visual processing engages the higher order, context dependent properties of neurons. Even at the earliest stages of visual cortical processing neurons play a role in intermediate level vision - contour integration and surface segmentation. The contextual influences mediating this process may be derived from long range connections within primary visual cortex (V1). These influences are subject to perceptual learning, and are strongly modulated by visuospatial attention, which is itself a learning dependent process. The attentional influences may involve interactions between feedback and horizontal connections in V1. V1 is therefore a dynamic and active processor, subject to top-down influences.

Parallel neural pathways in higher visual centers of the Drosophila brain that mediate wavelength-specific behavior

PubMed Central

Otsuna, Hideo; Shinomiya, Kazunori; Ito, Kei

2014-01-01

Compared with connections between the retinae and primary visual centers, relatively less is known in both mammals and insects about the functional segregation of neural pathways connecting primary and higher centers of the visual processing cascade. Here, using the Drosophila visual system as a model, we demonstrate two levels of parallel computation in the pathways that connect primary visual centers of the optic lobe to computational circuits embedded within deeper centers in the central brain. We show that a seemingly simple achromatic behavior, namely phototaxis, is under the control of several independent pathways, each of which is responsible for navigation towards unique wavelengths. Silencing just one pathway is enough to disturb phototaxis towards one characteristic monochromatic source, whereas phototactic behavior towards white light is not affected. The response spectrum of each demonstrable pathway is different from that of individual photoreceptors, suggesting subtractive computations. A choice assay between two colors showed that these pathways are responsible for navigation towards, but not for the detection itself of, the monochromatic light. The present study provides novel insights about how visual information is separated and processed in parallel to achieve robust control of an innate behavior. PMID:24574974

A Simple Network Architecture Accounts for Diverse Reward Time Responses in Primary Visual Cortex

PubMed Central

Hussain Shuler, Marshall G.; Shouval, Harel Z.

2015-01-01

Many actions performed by animals and humans depend on an ability to learn, estimate, and produce temporal intervals of behavioral relevance. Exemplifying such learning of cued expectancies is the observation of reward-timing activity in the primary visual cortex (V1) of rodents, wherein neural responses to visual cues come to predict the time of future reward as behaviorally experienced in the past. These reward-timing responses exhibit significant heterogeneity in at least three qualitatively distinct classes: sustained increase or sustained decrease in firing rate until the time of expected reward, and a class of cells that reach a peak in firing at the expected delay. We elaborate upon our existing model by including inhibitory and excitatory units while imposing simple connectivity rules to demonstrate what role these inhibitory elements and the simple architectures play in sculpting the response dynamics of the network. We find that simply adding inhibition is not sufficient for obtaining the different distinct response classes, and that a broad distribution of inhibitory projections is necessary for obtaining peak-type responses. Furthermore, although changes in connection strength that modulate the effects of inhibition onto excitatory units have a strong impact on the firing rate profile of these peaked responses, the network exhibits robustness in its overall ability to predict the expected time of reward. Finally, we demonstrate how the magnitude of expected reward can be encoded at the expected delay in the network and how peaked responses express this reward expectancy. SIGNIFICANCE STATEMENT Heterogeneity in single-neuron responses is a common feature of neuronal systems, although sometimes, in theoretical approaches, it is treated as a nuisance and seldom considered as conveying a different aspect of a signal. In this study, we focus on the heterogeneous responses in the primary visual cortex of rodents trained with a predictable delayed reward time. We describe under what conditions this heterogeneity can arise by self-organization, and what information it can convey. This study, while focusing on a specific system, provides insight onto how heterogeneity can arise in general while also shedding light onto mechanisms of reinforcement learning using realistic biological assumptions. PMID:26377457

Enduring critical period plasticity visualized by transcranial flavoprotein imaging in mouse primary visual cortex.

PubMed

Tohmi, Manavu; Kitaura, Hiroki; Komagata, Seiji; Kudoh, Masaharu; Shibuki, Katsuei

2006-11-08

Experience-dependent plasticity in the visual cortex was investigated using transcranial flavoprotein fluorescence imaging in mice anesthetized with urethane. On- and off-responses in the primary visual cortex were elicited by visual stimuli. Fluorescence responses and field potentials elicited by grating patterns decreased similarly as contrasts of visual stimuli were reduced. Fluorescence responses also decreased as spatial frequency of grating stimuli increased. Compared with intrinsic signal imaging in the same mice, fluorescence imaging showed faster responses with approximately 10 times larger signal changes. Retinotopic maps in the primary visual cortex and area LM were constructed using fluorescence imaging. After monocular deprivation (MD) of 4 d starting from postnatal day 28 (P28), deprived eye responses were suppressed compared with nondeprived eye responses in the binocular zone but not in the monocular zone. Imaging faithfully recapitulated a critical period for plasticity with maximal effects of MD observed around P28 and not in adulthood even under urethane anesthesia. Visual responses were compared before and after MD in the same mice, in which the skull was covered with clear acrylic dental resin. Deprived eye responses decreased after MD, whereas nondeprived eye responses increased. Effects of MD during a critical period were tested 2 weeks after reopening of the deprived eye. Significant ocular dominance plasticity was observed in responses elicited by moving grating patterns, but no long-lasting effect was found in visual responses elicited by light-emitting diode light stimuli. The present results indicate that transcranial flavoprotein fluorescence imaging is a powerful tool for investigating experience-dependent plasticity in the mouse visual cortex.

The Puzzle of Visual Development: Behavior and Neural Limits.

PubMed

Kiorpes, Lynne

2016-11-09

The development of visual function takes place over many months or years in primate infants. Visual sensitivity is very poor near birth and improves over different times courses for different visual functions. The neural mechanisms that underlie these processes are not well understood despite many decades of research. The puzzle arises because research into the factors that limit visual function in infants has found surprisingly mature neural organization and adult-like receptive field properties in very young infants. The high degree of visual plasticity that has been documented during the sensitive period in young children and animals leaves the brain vulnerable to abnormal visual experience. Abnormal visual experience during the sensitive period can lead to amblyopia, a developmental disorder of vision affecting ∼3% of children. This review provides a historical perspective on research into visual development and the disorder amblyopia. The mismatch between the status of the primary visual cortex and visual behavior, both during visual development and in amblyopia, is discussed, and several potential resolutions are considered. It seems likely that extrastriate visual areas further along the visual pathways may set important limits on visual function and show greater vulnerability to abnormal visual experience. Analyses based on multiunit, population activity may provide useful representations of the information being fed forward from primary visual cortex to extrastriate processing areas and to the motor output. Copyright © 2016 the authors 0270-6474/16/3611384-10$15.00/0.

The reward of seeing: Different types of visual reward and their ability to modify oculomotor learning.

PubMed

Meermeier, Annegret; Gremmler, Svenja; Richert, Kerstin; Eckermann, Til; Lappe, Markus

2017-10-01

Saccadic adaptation is an oculomotor learning process that maintains the accuracy of eye movements to ensure effective perception of the environment. Although saccadic adaptation is commonly considered an automatic and low-level motor calibration in the cerebellum, we recently found that strength of adaptation is influenced by the visual content of the target: pictures of humans produced stronger adaptation than noise stimuli. This suggests that meaningful images may be considered rewarding or valuable in oculomotor learning. Here we report three experiments that establish the boundaries of this effect. In the first, we tested whether stimuli that were associated with high and low value following long term self-administered reinforcement learning produce stronger adaptation. Twenty-eight expert gamers participated in two sessions of adaptation to game-related high- and low-reward stimuli, but revealed no difference in saccadic adaptation (Bayes Factor01 = 5.49). In the second experiment, we tested whether cognitive (literate) meaning could induce stronger adaptation by comparing targets consisting of words and nonwords. The results of twenty subjects revealed no difference in adaptation strength (Bayes Factor01 = 3.21). The third experiment compared images of human figures to noise patterns for reactive saccades. Twenty-two subjects adapted significantly more toward images of human figures in comparison to noise (p < 0.001). We conclude that only primary (human vs. noise), but not secondary, reinforcement affects saccadic adaptation (words vs. nonwords, high- vs. low-value video game images).

Fluorescence imaging of angiogenesis in green fluorescent protein-expressing tumors

NASA Astrophysics Data System (ADS)

Yang, Meng; Baranov, Eugene; Jiang, Ping; Li, Xiao-Ming; Wang, Jin W.; Li, Lingna; Yagi, Shigeo; Moossa, A. R.; Hoffman, Robert M.

2002-05-01

The development of therapeutics for the control of tumor angiogenesis requires a simple, reliable in vivo assay for tumor-induced vascularization. For this purpose, we have adapted the orthotopic implantation model of angiogenesis by using human and rodent tumors genetically tagged with Aequorea victoria green fluorescent protein (GFP) for grafting into nude mice. Genetically-fluorescent tumors can be readily imaged in vivo. The non-luminous induced capillaries are clearly visible against the bright tumor fluorescence examined either intravitally or by whole-body luminance in real time. Fluorescence shadowing replaces the laborious histological techniques for determining blood vessel density. High-level GFP-expressing tumor cell lines made it possible to acquire the high-resolution real-time fluorescent optical images of angiogenesis in both primary tumors and their metastatic lesions in various human and rodent tumor models by means of a light-based imaging system. Intravital images of angiogenesis onset and development were acquired and quantified from a GFP- expressing orthotopically-growing human prostate tumor over a 19-day period. Whole-body optical imaging visualized vessel density increasing linearly over a 20-week period in orthotopically-growing, GFP-expressing human breast tumor MDA-MB-435. Vessels in an orthotopically-growing GFP- expressing Lewis lung carcinoma tumor were visualized through the chest wall via a reversible skin flap. These clinically-relevant angiogenesis mouse models can be used for real-time in vivo evaluation of agents inhibiting or promoting tumor angiogenesis in physiological micro- environments.

Ocular input for human melatonin regulation: relevance to breast cancer

NASA Technical Reports Server (NTRS)

Glickman, Gena; Levin, Robert; Brainard, George C.

2002-01-01

The impact of breast cancer on women across the world has been extensive and severe. As prevalence of breast cancer is greatest in industrialized regions, exposure to light at night has been proposed as a potential risk factor. This theory is supported by the epidemiological observations of decreased breast cancer in blind women and increased breast cancer in women who do shift-work. In addition, human, animal and in vitro studies which have investigated the melatonin-cancer dynamic indicate an apparent relationship between light, melatonin and cancer, albeit complex. Recent developments in understanding melatonin regulation by light in humans are examined, with particular attention to factors that contribute to the sensitivity of the light-induced melatonin suppression response. Specifically, the role of spectral characteristics of light is addressed, and recent relevant action spectrum studies in humans and other mammalian species are discussed. Across five action spectra for circadian and other non-visual responses, a peak sensitivity between 446-484 nm was identified. Under highly controlled exposure circumstances, less than 1 lux of monochromatic light elicited a significant suppression of nocturnal melatonin. In view of the possible link between light exposure, melatonin suppression and cancer risk, it is important to continue to identify the basic related ocular physiology. Visual performance, rather than circadian function, has been the primary focus of architectural lighting systems. It is now necessary to reevaluate lighting strategies, with consideration of circadian influences, in an effort to maximize physiological homeostasis and health.

Ocular input for human melatonin regulation: relevance to breast cancer.

PubMed

Glickman, Gena; Levin, Robert; Brainard, George C

2002-07-01

The impact of breast cancer on women across the world has been extensive and severe. As prevalence of breast cancer is greatest in industrialized regions, exposure to light at night has been proposed as a potential risk factor. This theory is supported by the epidemiological observations of decreased breast cancer in blind women and increased breast cancer in women who do shift-work. In addition, human, animal and in vitro studies which have investigated the melatonin-cancer dynamic indicate an apparent relationship between light, melatonin and cancer, albeit complex. Recent developments in understanding melatonin regulation by light in humans are examined, with particular attention to factors that contribute to the sensitivity of the light-induced melatonin suppression response. Specifically, the role of spectral characteristics of light is addressed, and recent relevant action spectrum studies in humans and other mammalian species are discussed. Across five action spectra for circadian and other non-visual responses, a peak sensitivity between 446-484 nm was identified. Under highly controlled exposure circumstances, less than 1 lux of monochromatic light elicited a significant suppression of nocturnal melatonin. In view of the possible link between light exposure, melatonin suppression and cancer risk, it is important to continue to identify the basic related ocular physiology. Visual performance, rather than circadian function, has been the primary focus of architectural lighting systems. It is now necessary to reevaluate lighting strategies, with consideration of circadian influences, in an effort to maximize physiological homeostasis and health.

The evolution of the complex sensory and motor systems of the human brain.

PubMed

Kaas, Jon H

2008-03-18

Inferences about how the complex sensory and motor systems of the human brain evolved are based on the results of comparative studies of brain organization across a range of mammalian species, and evidence from the endocasts of fossil skulls of key extinct species. The endocasts of the skulls of early mammals indicate that they had small brains with little neocortex. Evidence from comparative studies of cortical organization from small-brained mammals of the six major branches of mammalian evolution supports the conclusion that the small neocortex of early mammals was divided into roughly 20-25 cortical areas, including primary and secondary sensory fields. In early primates, vision was the dominant sense, and cortical areas associated with vision in temporal and occipital cortex underwent a significant expansion. Comparative studies indicate that early primates had 10 or more visual areas, and somatosensory areas with expanded representations of the forepaw. Posterior parietal cortex was also expanded, with a caudal half dominated by visual inputs, and a rostral half dominated by somatosensory inputs with outputs to an array of seven or more motor and visuomotor areas of the frontal lobe. Somatosensory areas and posterior parietal cortex became further differentiated in early anthropoid primates. As larger brains evolved in early apes and in our hominin ancestors, the number of cortical areas increased to reach an estimated 200 or so in present day humans, and hemispheric specializations emerged. The large human brain grew primarily by increasing neuron number rather than increasing average neuron size.

In-vitro Thermal Maps to Characterize Human Dental Enamel and Dentin.

PubMed

Lancaster, Paula; Brettle, David; Carmichael, Fiona; Clerehugh, Val

2017-01-01

The crown of a human tooth has an outer layer of highly-mineralized tissue called enamel, beneath which is dentin, a less-mineralized tissue which forms the bulk of the tooth-crown and root. The composition and structure of enamel and dentin are different, resulting in different thermal properties. This gives an opportunity to characterize enamel and dentin from their thermal properties and to visually present the findings as a thermal map. The thermal properties of demineralized enamel and dentin may also be sufficiently different from sound tissue to be seen on a thermal map, underpinning future thermal assessment of caries. The primary aim of this novel study was to produce a thermal map of a sound, human tooth-slice to visually characterize enamel and dentin. The secondary aim was to map a human tooth-slice with demineralized enamel and dentin to consider future diagnostic potential of thermal maps for caries-detection. Two human slices of teeth, one sound and one demineralized from a natural carious lesion, were cooled on ice, then transferred to a hotplate at 30°C where the rewarming-sequence was captured by an infra-red thermal camera. Calculation of thermal diffusivity and thermal conductivity was undertaken, and two methods of data-processing used customized software to produce thermal maps from the thermal characteristic-time-to-relaxation and heat-exchange. The two types of thermal maps characterized enamel and dentin. In addition, sound and demineralized enamel and dentin were distinguishable within both maps. This supports thermal assessment of caries and requires further investigation on a whole tooth.

A Computational Model of Spatial Visualization Capacity

ERIC Educational Resources Information Center

Lyon, Don R.; Gunzelmann, Glenn; Gluck, Kevin A.

2008-01-01

Visualizing spatial material is a cornerstone of human problem solving, but human visualization capacity is sharply limited. To investigate the sources of this limit, we developed a new task to measure visualization accuracy for verbally-described spatial paths (similar to street directions), and implemented a computational process model to…

Visual training paired with electrical stimulation of the basal forebrain improves orientation-selective visual acuity in the rat.

PubMed

Kang, Jun Il; Groleau, Marianne; Dotigny, Florence; Giguère, Hugo; Vaucher, Elvire

2014-07-01

The cholinergic afferents from the basal forebrain to the primary visual cortex play a key role in visual attention and cortical plasticity. These afferent fibers modulate acute and long-term responses of visual neurons to specific stimuli. The present study evaluates whether this cholinergic modulation of visual neurons results in cortical activity and visual perception changes. Awake adult rats were exposed repeatedly for 2 weeks to an orientation-specific grating with or without coupling this visual stimulation to an electrical stimulation of the basal forebrain. The visual acuity, as measured using a visual water maze before and after the exposure to the orientation-specific grating, was increased in the group of trained rats with simultaneous basal forebrain/visual stimulation. The increase in visual acuity was not observed when visual training or basal forebrain stimulation was performed separately or when cholinergic fibers were selectively lesioned prior to the visual stimulation. The visual evoked potentials show a long-lasting increase in cortical reactivity of the primary visual cortex after coupled visual/cholinergic stimulation, as well as c-Fos immunoreactivity of both pyramidal and GABAergic interneuron. These findings demonstrate that when coupled with visual training, the cholinergic system improves visual performance for the trained orientation probably through enhancement of attentional processes and cortical plasticity in V1 related to the ratio of excitatory/inhibitory inputs. This study opens the possibility of establishing efficient rehabilitation strategies for facilitating visual capacity.

Reducing Problems in Fine Motor Development among Primary Children through the Use of Multi-Sensory Techniques.

ERIC Educational Resources Information Center

Wessel, Dorothy

A 10-week classroom intervention program was implemented to facilitate the fine-motor development of eight first-grade children assessed as being deficient in motor skills. The program was divided according to five deficits to be remediated: visual motor, visual discrimination, visual sequencing, visual figure-ground, and visual memory. Each area…

Robotic Attention Processing And Its Application To Visual Guidance

NASA Astrophysics Data System (ADS)

Barth, Matthew; Inoue, Hirochika

1988-03-01

This paper describes a method of real-time visual attention processing for robots performing visual guidance. This robot attention processing is based on a novel vision processor, the multi-window vision system that was developed at the University of Tokyo. The multi-window vision system is unique in that it only processes visual information inside local area windows. These local area windows are quite flexible in their ability to move anywhere on the visual screen, change their size and shape, and alter their pixel sampling rate. By using these windows for specific attention tasks, it is possible to perform high speed attention processing. The primary attention skills of detecting motion, tracking an object, and interpreting an image are all performed at high speed on the multi-window vision system. A basic robotic attention scheme using the attention skills was developed. The attention skills involved detection and tracking of salient visual features. The tracking and motion information thus obtained was utilized in producing the response to the visual stimulus. The response of the attention scheme was quick enough to be applicable to the real-time vision processing tasks of playing a video 'pong' game, and later using an automobile driving simulator. By detecting the motion of a 'ball' on a video screen and then tracking the movement, the attention scheme was able to control a 'paddle' in order to keep the ball in play. The response was faster than that of a human's, allowing the attention scheme to play the video game at higher speeds. Further, in the application to the driving simulator, the attention scheme was able to control both direction and velocity of a simulated vehicle following a lead car. These two applications show the potential of local visual processing in its use for robotic attention processing.

Local activity determines functional connectivity in the resting human brain: a simultaneous FDG-PET/fMRI study.

PubMed

Riedl, Valentin; Bienkowska, Katarzyna; Strobel, Carola; Tahmasian, Masoud; Grimmer, Timo; Förster, Stefan; Friston, Karl J; Sorg, Christian; Drzezga, Alexander

2014-04-30

Over the last decade, synchronized resting-state fluctuations of blood oxygenation level-dependent (BOLD) signals between remote brain areas [so-called BOLD resting-state functional connectivity (rs-FC)] have gained enormous relevance in systems and clinical neuroscience. However, the neural underpinnings of rs-FC are still incompletely understood. Using simultaneous positron emission tomography/magnetic resonance imaging we here directly investigated the relationship between rs-FC and local neuronal activity in humans. Computational models suggest a mechanistic link between the dynamics of local neuronal activity and the functional coupling among distributed brain regions. Therefore, we hypothesized that the local activity (LA) of a region at rest determines its rs-FC. To test this hypothesis, we simultaneously measured both LA (glucose metabolism) and rs-FC (via synchronized BOLD fluctuations) during conditions of eyes closed or eyes open. During eyes open, LA increased in the visual system, and the salience network (i.e., cingulate and insular cortices) and the pattern of elevated LA coincided almost exactly with the spatial pattern of increased rs-FC. Specifically, the voxelwise regional profile of LA in these areas strongly correlated with the regional pattern of rs-FC among the same regions (e.g., LA in primary visual cortex accounts for ∼ 50%, and LA in anterior cingulate accounts for ∼ 20% of rs-FC with the visual system). These data provide the first direct evidence in humans that local neuronal activity determines BOLD FC at rest. Beyond its relevance for the neuronal basis of coherent BOLD signal fluctuations, our procedure may translate into clinical research particularly to investigate potentially aberrant links between local dynamics and remote functional coupling in patients with neuropsychiatric disorders.

Outcome of in-the-bag implanted square-edge polymethyl methacrylate intraocular lenses with and without primary posterior capsulotomy in pediatric traumatic cataract

PubMed Central

Verma, Neelam; Ram, Jagat; Sukhija, Jaspreet; Pandav, Surinder S.; Gupta, Amit

2011-01-01

Purpose: To study the outcome of in-the-bag implanted square-edge polymethyl methacrylate (PMMA) intraocular lenses (IOL) with and without primary posterior capsulotomy in pediatric traumatic cataract. Materials and Methods: The study was undertaken in a tertiary care center. Thirty eyes of 30 children ranging in age from 4 to 16 years with traumatic cataract which underwent cataract extraction with capsular bag implantation of IOL were prospectively evaluated. Group A included 15 eyes of 15 children where primary posterior capsulotomy (PPC) and anterior vitrectomy with capsular bag implantation of square-edge PMMA IOL (Aurolab SQ3602, Madurai, Tamil Nadu, India) was performed. Group B comprised 15 eyes of 15 children in which the posterior capsule was left intact. Postoperative visual acuity, visual axis opacification (VAO) and possible complications were analyzed. Results: Best corrected visual acuity (BCVA) of 20/40 or better was achieved in 12 of 15 eyes in both groups. Amblyopia was the cause of no improvement in visual acuity in the remaining eyes. Visual axis opacification was significantly high in Group B as compared to Group A (P=0.001). Postoperative fibrinous uveitis occurred in most of the eyes in both groups. Pupillary capture was observed in one eye in each group. Conclusion: Primary posterior capsulotomy and anterior vitrectomy with capsular bag implantation of square-edge PMMA significantly helps to maintain a clear visual axis in children with traumatic cataract. PMID:21836338

Non-cultural methods of human microflora evaluation for the benefit of crew medical control in confined habitat

NASA Astrophysics Data System (ADS)

Viacheslav, Ilyin; Lana, Moukhamedieva; Georgy, Osipov; Aleksey, Batov; Zoya, Soloviova; Robert, Mardanov; Yana, Panina; Anna, Gegenava

2011-05-01

Current control of human microflora is a great problem not only for the space medicine but also for practical health care. Due to many reasons its realization by classical bacteriological method is difficult in practical application or cannot be done. To evaluate non-cultural methods of microbial control of crews in a confined habitat we evaluated two different methods. The first method is based on digital treatment of microbial visual images, appearing after gram staining of microbial material from natural sample. This way the rate between gram-positive and gram-negative microbe could be gained as well as differentiation of rods and cocci could be attained, which is necessary for primary evaluation of human microbial cenosis in remote confined habitats. The other non-culture method of human microflora evaluation is gas chromatomass spectrometry (gcms) analysis of swabs gathered from different body sites. Gc-ms testing of swabs allows one to validate quantitative and special microflora based on specific lipid markers analysis.

Active and passive spatial learning in human navigation: acquisition of graph knowledge.

PubMed

Chrastil, Elizabeth R; Warren, William H

2015-07-01

It is known that active exploration of a new environment leads to better spatial learning than does passive visual exposure. We ask whether specific components of active learning differentially contribute to particular forms of spatial knowledge-the exploration-specific learning hypothesis. Previously, we found that idiothetic information during walking is the primary active contributor to metric survey knowledge (Chrastil & Warren, 2013). In this study, we test the contributions of 3 components to topological graph and route knowledge: visual information, idiothetic information, and cognitive decision making. Four groups of participants learned the locations of 8 objects in a virtual hedge maze by (a) walking or (b) watching a video, crossed with (1) either making decisions about their path or (2) being guided through the maze. Route and graph knowledge were assessed by walking in the maze corridors from a starting object to the remembered location of a test object, with frequent detours. Decision making during exploration significantly contributed to subsequent route finding in the walking condition, whereas idiothetic information did not. Participants took novel routes and the metrically shortest routes on the majority of both direct and barrier trials, indicating that labeled graph knowledge-not merely route knowledge-was acquired. We conclude that, consistent with the exploration-specific learning hypothesis, decision making is the primary component of active learning for the acquisition of topological graph knowledge, whereas idiothetic information is the primary component for metric survey knowledge. (c) 2015 APA, all rights reserved.

Entry Pathways of Herpes Simplex Virus Type 1 into Human Keratinocytes Are Dynamin- and Cholesterol-Dependent

PubMed Central

Hsu, Mei-Ju; Rixon, Frazer J.; Knebel-Mörsdorf, Dagmar

2011-01-01

Herpes simplex virus type 1 (HSV-1) can enter cells via endocytic pathways or direct fusion at the plasma membrane depending on the cell line and receptor(s). Most studies into virus entry have used cultured fibroblasts but since keratinocytes represent the primary entry site for HSV-1 infection in its human host, we initiated studies to characterize the entry pathway of HSV-1 into human keratinocytes. Electron microscopy studies visualized free capsids in the cytoplasm and enveloped virus particles in vesicles suggesting viral uptake both by direct fusion at the plasma membrane and by endocytic vesicles. The ratio of the two entry modes differed in primary human keratinocytes and in the keratinocyte cell line HaCaT. Inhibitor studies further support a role for endocytosis during HSV-1 entry. Infection was inhibited by the cholesterol-sequestering drug methyl-β-cyclodextrin, which demonstrates the requirement for host cholesterol during virus entry. Since the dynamin-specific inhibitor dynasore and overexpression of a dominant-negative dynamin mutant blocked infection, we conclude that the entry pathways into keratinocytes are dynamin-mediated. Electron microscopy studies confirmed that virus uptake is completely blocked when the GTPase activity of dynamin is inhibited. Ex vivo infection of murine epidermis that was treated with dynasore further supports the essential role of dynamin during entry into the epithelium. Thus, we conclude that HSV-1 can enter human keratinocytes by alternative entry pathways that require dynamin and host cholesterol. PMID:22022400

An eye movement analysis of the effect of interruption modality on primary task resumption.

PubMed

Ratwani, Raj; Trafton, J Gregory

2010-06-01

We examined the effect of interruption modality (visual or auditory) on primary task (visual) resumption to determine which modality was the least disruptive. Theories examining interruption modality have focused on specific periods of the interruption timeline. Preemption theory has focused on the switch from the primary task to the interrupting task. Multiple resource theory has focused on interrupting tasks that are to be performed concurrently with the primary task. Our focus was on examining how interruption modality influences task resumption.We leverage the memory-for-goals theory, which suggests that maintaining an associative link between environmental cues and the suspended primary task goal is important for resumption. Three interruption modality conditions were examined: auditory interruption with the primary task visible, auditory interruption with a blank screen occluding the primary task, and a visual interruption occluding the primary task. Reaction time and eye movement data were collected. The auditory condition with the primary task visible was the least disruptive. Eye movement data suggest that participants in this condition were actively maintaining an associative link between relevant environmental cues on the primary task interface and the suspended primary task goal during the interruption. These data suggest that maintaining cue association is the important factor for reducing the disruptiveness of interruptions, not interruption modality. Interruption-prone computing environments should be designed to allow for the user to have access to relevant primary task cues during an interruption to minimize disruptiveness.

Suggested Activities to Use With Children Who Present Symptoms of Visual Perception Problems, Elementary Level.

ERIC Educational Resources Information Center

Washington County Public Schools, Washington, PA.

Symptoms displayed by primary age children with learning disabilities are listed; perceptual handicaps are explained. Activities are suggested for developing visual perception and perception involving motor activities. Also suggested are activities to develop body concept, visual discrimination and attentiveness, visual memory, and figure ground…

Relationship between BOLD amplitude and pattern classification of orientation-selective activity in the human visual cortex.

PubMed

Tong, Frank; Harrison, Stephenie A; Dewey, John A; Kamitani, Yukiyasu

2012-11-15

Orientation-selective responses can be decoded from fMRI activity patterns in the human visual cortex, using multivariate pattern analysis (MVPA). To what extent do these feature-selective activity patterns depend on the strength and quality of the sensory input, and might the reliability of these activity patterns be predicted by the gross amplitude of the stimulus-driven BOLD response? Observers viewed oriented gratings that varied in luminance contrast (4, 20 or 100%) or spatial frequency (0.25, 1.0 or 4.0 cpd). As predicted, activity patterns in early visual areas led to better discrimination of orientations presented at high than low contrast, with greater effects of contrast found in area V1 than in V3. A second experiment revealed generally better decoding of orientations at low or moderate as compared to high spatial frequencies. Interestingly however, V1 exhibited a relative advantage at discriminating high spatial frequency orientations, consistent with the finer scale of representation in the primary visual cortex. In both experiments, the reliability of these orientation-selective activity patterns was well predicted by the average BOLD amplitude in each region of interest, as indicated by correlation analyses, as well as decoding applied to a simple model of voxel responses to simulated orientation columns. Moreover, individual differences in decoding accuracy could be predicted by the signal-to-noise ratio of an individual's BOLD response. Our results indicate that decoding accuracy can be well predicted by incorporating the amplitude of the BOLD response into simple simulation models of cortical selectivity; such models could prove useful in future applications of fMRI pattern classification. Copyright © 2012 Elsevier Inc. All rights reserved.

Relationship between BOLD amplitude and pattern classification of orientation-selective activity in the human visual cortex

PubMed Central

Tong, Frank; Harrison, Stephenie A.; Dewey, John A.; Kamitani, Yukiyasu

2012-01-01

Orientation-selective responses can be decoded from fMRI activity patterns in the human visual cortex, using multivariate pattern analysis (MVPA). To what extent do these feature-selective activity patterns depend on the strength and quality of the sensory input, and might the reliability of these activity patterns be predicted by the gross amplitude of the stimulus-driven BOLD response? Observers viewed oriented gratings that varied in luminance contrast (4, 20 or 100%) or spatial frequency (0.25, 1.0 or 4.0 cpd). As predicted, activity patterns in early visual areas led to better discrimination of orientations presented at high than low contrast, with greater effects of contrast found in area V1 than in V3. A second experiment revealed generally better decoding of orientations at low or moderate as compared to high spatial frequencies. Interestingly however, V1 exhibited a relative advantage at discriminating high spatial frequency orientations, consistent with the finer scale of representation in the primary visual cortex. In both experiments, the reliability of these orientation-selective activity patterns was well predicted by the average BOLD amplitude in each region of interest, as indicated by correlation analyses, as well as decoding applied to a simple model of voxel responses to simulated orientation columns. Moreover, individual differences in decoding accuracy could be predicted by the signal-to-noise ratio of an individual's BOLD response. Our results indicate that decoding accuracy can be well predicted by incorporating the amplitude of the BOLD response into simple simulation models of cortical selectivity; such models could prove useful in future applications of fMRI pattern classification. PMID:22917989

Spatial updating in human parietal cortex

NASA Technical Reports Server (NTRS)

Merriam, Elisha P.; Genovese, Christopher R.; Colby, Carol L.

2003-01-01

Single neurons in monkey parietal cortex update visual information in conjunction with eye movements. This remapping of stimulus representations is thought to contribute to spatial constancy. We hypothesized that a similar process occurs in human parietal cortex and that we could visualize it with functional MRI. We scanned subjects during a task that involved remapping of visual signals across hemifields. We observed an initial response in the hemisphere contralateral to the visual stimulus, followed by a remapped response in the hemisphere ipsilateral to the stimulus. We ruled out the possibility that this remapped response resulted from either eye movements or visual stimuli alone. Our results demonstrate that updating of visual information occurs in human parietal cortex.

Cognitive tunneling: use of visual information under stress.

PubMed

Dirkin, G R

1983-02-01

References to "tunnel vision" under stress are considered to describe a process of attentional, rather than visual, narrowing. The hypothesis of Easterbrook that the range of cue utilization is reduced under stress was tested with a primary task located in the visual periphery. High school volunteers performed a visual discrimination task with choice reaction time (RT) as the dependent variable. A 2 X 3 order of presentation by practice design, with repeated measures on the last factor, was employed. Two levels of stress, high and low, were operationalized by the subject's performing in the presence of an evaluative audience or alone. Pulse rate was employed as a manipulation check on arousal. The results partially supported the hypothesis that a peripherally visual primary task could be attended to under stress without decrement in performance.

Advances in understanding the molecular basis of the first steps in color vision

PubMed Central

Hofmann, Lukas; Palczewski, Krzysztof

2015-01-01

Serving as one of our primary environmental inputs, vision is the most sophisticated sensory system in humans. Here, we present recent findings derived from energetics, genetics and physiology that provide a more advanced understanding of color perception in mammals. Energetics of cis–trans isomerization of 11-cis-retinal accounts for color perception in the narrow region of the electromagnetic spectrum and how human eyes can absorb light in the near infrared (IR) range. Structural homology models of visual pigments reveal complex interactions of the protein moieties with the light sensitive chromophore 11-cis-retinal and that certain color blinding mutations impair secondary structural elements of these G protein-coupled receptors (GPCRs). Finally, we identify unsolved critical aspects of color tuning that require future investigation. PMID:26187035

Identification of a pathway for intelligible speech in the left temporal lobe

PubMed Central

Scott, Sophie K.; Blank, C. Catrin; Rosen, Stuart; Wise, Richard J. S.

2017-01-01

Summary It has been proposed that the identification of sounds, including species-specific vocalizations, by primates depends on anterior projections from the primary auditory cortex, an auditory pathway analogous to the ventral route proposed for the visual identification of objects. We have identified a similar route in the human for understanding intelligible speech. Using PET imaging to identify separable neural subsystems within the human auditory cortex, we used a variety of speech and speech-like stimuli with equivalent acoustic complexity but varying intelligibility. We have demonstrated that the left superior temporal sulcus responds to the presence of phonetic information, but its anterior part only responds if the stimulus is also intelligible. This novel observation demonstrates a left anterior temporal pathway for speech comprehension. PMID:11099443

Anatomical connections of the visual word form area.

PubMed

Bouhali, Florence; Thiebaut de Schotten, Michel; Pinel, Philippe; Poupon, Cyril; Mangin, Jean-François; Dehaene, Stanislas; Cohen, Laurent

2014-11-12

The visual word form area (VWFA), a region systematically involved in the identification of written words, occupies a reproducible location in the left occipitotemporal sulcus in expert readers of all cultures. Such a reproducible localization is paradoxical, given that reading is a recent invention that could not have influenced the genetic evolution of the cortex. Here, we test the hypothesis that the VWFA recycles a region of the ventral visual cortex that shows a high degree of anatomical connectivity to perisylvian language areas, thus providing an efficient circuit for both grapheme-phoneme conversion and lexical access. In two distinct experiments, using high-resolution diffusion-weighted data from 75 human subjects, we show that (1) the VWFA, compared with the fusiform face area, shows higher connectivity to left-hemispheric perisylvian superior temporal, anterior temporal and inferior frontal areas; (2) on a posterior-to-anterior axis, its localization within the left occipitotemporal sulcus maps onto a peak of connectivity with language areas, with slightly distinct subregions showing preferential projections to areas respectively involved in grapheme-phoneme conversion and lexical access. In agreement with functional data on the VWFA in blind subjects, the results suggest that connectivity to language areas, over and above visual factors, may be the primary determinant of VWFA localization. Copyright © 2014 the authors 0270-6474/14/3415402-13$15.00/0.

Deconstructing Immigrant Girls' Identities through the Production of Visual Narratives in a Catalan Urban Primary School

ERIC Educational Resources Information Center

Rifa-Valls, Montserrat

2009-01-01

In this article, the research findings of a deconstructive visual ethnography focused on the production of immigrant girls' identities will be analysed. This collaborative research project involved experimentation with a dialogic curriculum aimed at creating diverse identity narratives with immigrant girls at an urban primary school in Barcelona.…

The Analysis of Reading Skills and Visual Perception Levels of First Grade Turkish Students

ERIC Educational Resources Information Center

Memis, Aysel; Sivri, Diler Ayvaz

2016-01-01

In this study, primary school first grade students' reading skills and visual perception levels were investigated. Sample of the study, which was designed with relational scanning model, consisted of 168 first grade students studying at three public primary schools in Kozlu, Zonguldak, in 2013-2014 education year. Students' reading level, reading…

Optical images of visible and invisible percepts in the primary visual cortex of primates

PubMed Central

Macknik, Stephen L.; Haglund, Michael M.

1999-01-01

We optically imaged a visual masking illusion in primary visual cortex (area V-1) of rhesus monkeys to ask whether activity in the early visual system more closely reflects the physical stimulus or the generated percept. Visual illusions can be a powerful way to address this question because they have the benefit of dissociating the stimulus from perception. We used an illusion in which a flickering target (a bar oriented in visual space) is rendered invisible by two counter-phase flickering bars, called masks, which flank and abut the target. The target and masks, when shown separately, each generated correlated activity on the surface of the cortex. During the illusory condition, however, optical signals generated in the cortex by the target disappeared although the image of the masks persisted. The optical image thus was correlated with perception but not with the physical stimulus. PMID:10611363

Neuronal Representation of Ultraviolet Visual Stimuli in Mouse Primary Visual Cortex

PubMed Central

Tan, Zhongchao; Sun, Wenzhi; Chen, Tsai-Wen; Kim, Douglas; Ji, Na

2015-01-01

The mouse has become an important model for understanding the neural basis of visual perception. Although it has long been known that mouse lens transmits ultraviolet (UV) light and mouse opsins have absorption in the UV band, little is known about how UV visual information is processed in the mouse brain. Using a custom UV stimulation system and in vivo calcium imaging, we characterized the feature selectivity of layer 2/3 neurons in mouse primary visual cortex (V1). In adult mice, a comparable percentage of the neuronal population responds to UV and visible stimuli, with similar pattern selectivity and receptive field properties. In young mice, the orientation selectivity for UV stimuli increased steadily during development, but not direction selectivity. Our results suggest that, by expanding the spectral window through which the mouse can acquire visual information, UV sensitivity provides an important component for mouse vision. PMID:26219604

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

Human infrared vision is triggered by two-photon chromophore isomerization

PubMed Central

Palczewska, Grazyna; Vinberg, Frans; Stremplewski, Patrycjusz; Bircher, Martin P.; Salom, David; Komar, Katarzyna; Zhang, Jianye; Cascella, Michele; Wojtkowski, Maciej; Kefalov, Vladimir J.; Palczewski, Krzysztof

2014-01-01

Vision relies on photoactivation of visual pigments in rod and cone photoreceptor cells of the retina. The human eye structure and the absorption spectra of pigments limit our visual perception of light. Our visual perception is most responsive to stimulating light in the 400- to 720-nm (visible) range. First, we demonstrate by psychophysical experiments that humans can perceive infrared laser emission as visible light. Moreover, we show that mammalian photoreceptors can be directly activated by near infrared light with a sensitivity that paradoxically increases at wavelengths above 900 nm, and display quadratic dependence on laser power, indicating a nonlinear optical process. Biochemical experiments with rhodopsin, cone visual pigments, and a chromophore model compound 11-cis-retinyl-propylamine Schiff base demonstrate the direct isomerization of visual chromophore by a two-photon chromophore isomerization. Indeed, quantum mechanics modeling indicates the feasibility of this mechanism. Together, these findings clearly show that human visual perception of near infrared light occurs by two-photon isomerization of visual pigments. PMID:25453064

Modulation of visually evoked movement responses in moving virtual environments.

PubMed

Reed-Jones, Rebecca J; Vallis, Lori Ann

2009-01-01

Virtual-reality technology is being increasingly used to understand how humans perceive and act in the moving world around them. What is currently not clear is how virtual reality technology is perceived by human participants and what virtual scenes are effective in evoking movement responses to visual stimuli. We investigated the effect of virtual-scene context on human responses to a virtual visual perturbation. We hypothesised that exposure to a natural scene that matched the visual expectancies of the natural world would create a perceptual set towards presence, and thus visual guidance of body movement in a subsequently presented virtual scene. Results supported this hypothesis; responses to a virtual visual perturbation presented in an ambiguous virtual scene were increased when participants first viewed a scene that consisted of natural landmarks which provided 'real-world' visual motion cues. Further research in this area will provide a basis of knowledge for the effective use of this technology in the study of human movement responses.

The Role of the Human Extrastriate Visual Cortex in Mirror Symmetry Discrimination: A TMS-Adaptation Study

ERIC Educational Resources Information Center

Cattaneo, Zaira; Mattavelli, Giulia; Papagno, Costanza; Herbert, Andrew; Silvanto, Juha

2011-01-01

The human visual system is able to efficiently extract symmetry information from the visual environment. Prior neuroimaging evidence has revealed symmetry-preferring neuronal representations in the dorsolateral extrastriate visual cortex; the objective of the present study was to investigate the necessity of these representations in symmetry…

Visual Graphics for Human Rights, Social Justice, Democracy and the Public Good

ERIC Educational Resources Information Center

Nanackchand, Vedant; Berman, Kim

2012-01-01

The value of human rights in a democratic South Africa is constantly threatened and often waived for nefarious reasons. We contend that the use of visual graphics among incoming university visual art students provides a mode of engagement that helps to inculcate awareness of human rights, social responsibility, and the public good in South African…

Do you see what I see? The difference between dog and human visual perception may affect the outcome of experiments.

PubMed

Pongrácz, Péter; Ujvári, Vera; Faragó, Tamás; Miklósi, Ádám; Péter, András

2017-07-01

The visual sense of dogs is in many aspects different than that of humans. Unfortunately, authors do not explicitly take into consideration dog-human differences in visual perception when designing their experiments. With an image manipulation program we altered stationary images, according to the present knowledge about dog-vision. Besides the effect of dogs' dichromatic vision, the software shows the effect of the lower visual acuity and brightness discrimination, too. Fifty adult humans were tested with pictures showing a female experimenter pointing, gazing or glancing to the left or right side. Half of the pictures were shown after they were altered to a setting that approximated dog vision. Participants had difficulty to find out the direction of glancing when the pictures were in dog-vision mode. Glances in dog-vision setting were followed less correctly and with a slower response time than other cues. Our results are the first that show the visual performance of humans under circumstances that model how dogs' weaker vision would affect their responses in an ethological experiment. We urge researchers to take into consideration the differences between perceptual abilities of dogs and humans, by developing visual stimuli that fit more appropriately to dogs' visual capabilities. Copyright © 2017 Elsevier B.V. All rights reserved.

[Retinotopic mapping of the human visual cortex with functional magnetic resonance imaging - basic principles, current developments and ophthalmological perspectives].

PubMed

Hoffmann, M B; Kaule, F; Grzeschik, R; Behrens-Baumann, W; Wolynski, B

2011-07-01

Since its initial introduction in the mid-1990 s, retinotopic mapping of the human visual cortex, based on functional magnetic resonance imaging (fMRI), has contributed greatly to our understanding of the human visual system. Multiple cortical visual field representations have been demonstrated and thus numerous visual areas identified. The organisation of specific areas has been detailed and the impact of pathophysiologies of the visual system on the cortical organisation uncovered. These results are based on investigations at a magnetic field strength of 3 Tesla or less. In a field-strength comparison between 3 and 7 Tesla, it was demonstrated that retinotopic mapping benefits from a magnetic field strength of 7 Tesla. Specifically, the visual areas can be mapped with high spatial resolution for a detailed analysis of the visual field maps. Applications of fMRI-based retinotopic mapping in ophthalmological research hold promise to further our understanding of plasticity in the human visual cortex. This is highlighted by pioneering studies in patients with macular dysfunction or misrouted optic nerves. © Georg Thieme Verlag KG Stuttgart · New York.

Modeling human comprehension of data visualizations

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

Matzen, Laura E.; Haass, Michael Joseph; Divis, Kristin Marie

This project was inspired by two needs. The first is a need for tools to help scientists and engineers to design effective data visualizations for communicating information, whether to the user of a system, an analyst who must make decisions based on complex data, or in the context of a technical report or publication. Most scientists and engineers are not trained in visualization design, and they could benefit from simple metrics to assess how well their visualization's design conveys the intended message. In other words, will the most important information draw the viewer's attention? The second is the need formore » cognition-based metrics for evaluating new types of visualizations created by researchers in the information visualization and visual analytics communities. Evaluating visualizations is difficult even for experts. However, all visualization methods and techniques are intended to exploit the properties of the human visual system to convey information efficiently to a viewer. Thus, developing evaluation methods that are rooted in the scientific knowledge of the human visual system could be a useful approach. In this project, we conducted fundamental research on how humans make sense of abstract data visualizations, and how this process is influenced by their goals and prior experience. We then used that research to develop a new model, the Data Visualization Saliency Model, that can make accurate predictions about which features in an abstract visualization will draw a viewer's attention. The model is an evaluation tool that can address both of the needs described above, supporting both visualization research and Sandia mission needs.« less

Hybridization between Media Education and Visual Arts Education. Miyazaki's Cinema as a Revulsive

ERIC Educational Resources Information Center

Huerta, Ricard

2011-01-01

In this article we suggest an approximation between media education and visual arts education. Teachers of Primary School interpret the media as a visual artefacts. But these visual artifacts can be analyzed from the education in visual arts. We can offer a suitable formation in the moment on training teachers (Clarembeaux, 2010; Huerta, 2005),…

Exploring human disease using the Rat Genome Database.

PubMed

Shimoyama, Mary; Laulederkind, Stanley J F; De Pons, Jeff; Nigam, Rajni; Smith, Jennifer R; Tutaj, Marek; Petri, Victoria; Hayman, G Thomas; Wang, Shur-Jen; Ghiasvand, Omid; Thota, Jyothi; Dwinell, Melinda R

2016-10-01

Rattus norvegicus, the laboratory rat, has been a crucial model for studies of the environmental and genetic factors associated with human diseases for over 150 years. It is the primary model organism for toxicology and pharmacology studies, and has features that make it the model of choice in many complex-disease studies. Since 1999, the Rat Genome Database (RGD; http://rgd.mcw.edu) has been the premier resource for genomic, genetic, phenotype and strain data for the laboratory rat. The primary role of RGD is to curate rat data and validate orthologous relationships with human and mouse genes, and make these data available for incorporation into other major databases such as NCBI, Ensembl and UniProt. RGD also provides official nomenclature for rat genes, quantitative trait loci, strains and genetic markers, as well as unique identifiers. The RGD team adds enormous value to these basic data elements through functional and disease annotations, the analysis and visual presentation of pathways, and the integration of phenotype measurement data for strains used as disease models. Because much of the rat research community focuses on understanding human diseases, RGD provides a number of datasets and software tools that allow users to easily explore and make disease-related connections among these datasets. RGD also provides comprehensive human and mouse data for comparative purposes, illustrating the value of the rat in translational research. This article introduces RGD and its suite of tools and datasets to researchers - within and beyond the rat community - who are particularly interested in leveraging rat-based insights to understand human diseases. © 2016. Published by The Company of Biologists Ltd.

Therapeutic Options for Controlling Fluids in the Visual System

NASA Technical Reports Server (NTRS)

Curry, Kristina M.; Wotring, Virginia E.

2014-01-01

Visual Impairment/Intracranial Pressure (VIIP) is a newly recognized risk at NASA. The VIIP project examines the effect of long-term exposure to microgravity on vision of crewmembers before and after they return to Earth. Diamox (acetazolamide) is a medication which is used to decrease intraocular pressure; however, it carries a 3% risk of kidney stones. Astronauts are at a higher risk of kidney stones during spaceflight and the use Diamox would only increase the risk; therefore alternative therapies were investigated. Histamine 2 (H2) antagonist acid blockers such as cimetidine, ranitidine, famotidine and nizatidine are typically used to relieve the symptoms of gastroesophageal reflux disease (GERD). H2 receptors have been found in the human visual system, which has led to research on the use of H2 antagonist blockers to control fluid production in the human eye. Another potential therapeutic strategy is targeted at aquaporins, which are water channels that help maintain fluid homeostasis. Aquaporin antagonists are also known to affect intracranial pressure which can in turn alter intraocular pressure. Studies on aquaporin antagonists suggest high potential for effective treatment. The primary objective of this investigation is to review existing research on alternate medications or therapy to significantly reduce intracranial and intraocular pressure. A literature review was conducted. Even though we do not have all the answers quite yet, a considerable amount of information was discovered, and findings were narrowed, which should allow for more conclusive answers to be found in the near future.

Plasticity and stability of visual field maps in adult primary visual cortex

PubMed Central

Wandell, Brian A.; Smirnakis, Stelios M.

2010-01-01

Preface It is important to understand the balance between cortical plasticity and stability in various systems and spatial scales in the adult brain. We review measurements of adult plasticity in primary visual cortex (V1), a structure that has a key role in distributing visual information. There are claims of plasticity at multiple spatial scales in adult V1, but many inconsistencies in the data raise questions about the extent and nature of such plasticity. Understanding is further limited by a lack of quantitative models to guide the interpretation of the data. These problems limit efforts to translate research findings about adult cortical plasticity into significant clinical, educational and policy applications. PMID:19904279

Mouth and Voice: A Relationship between Visual and Auditory Preference in the Human Superior Temporal Sulcus

PubMed Central

2017-01-01

Cortex in and around the human posterior superior temporal sulcus (pSTS) is known to be critical for speech perception. The pSTS responds to both the visual modality (especially biological motion) and the auditory modality (especially human voices). Using fMRI in single subjects with no spatial smoothing, we show that visual and auditory selectivity are linked. Regions of the pSTS were identified that preferred visually presented moving mouths (presented in isolation or as part of a whole face) or moving eyes. Mouth-preferring regions responded strongly to voices and showed a significant preference for vocal compared with nonvocal sounds. In contrast, eye-preferring regions did not respond to either vocal or nonvocal sounds. The converse was also true: regions of the pSTS that showed a significant response to speech or preferred vocal to nonvocal sounds responded more strongly to visually presented mouths than eyes. These findings can be explained by environmental statistics. In natural environments, humans see visual mouth movements at the same time as they hear voices, while there is no auditory accompaniment to visual eye movements. The strength of a voxel's preference for visual mouth movements was strongly correlated with the magnitude of its auditory speech response and its preference for vocal sounds, suggesting that visual and auditory speech features are coded together in small populations of neurons within the pSTS. SIGNIFICANCE STATEMENT Humans interacting face to face make use of auditory cues from the talker's voice and visual cues from the talker's mouth to understand speech. The human posterior superior temporal sulcus (pSTS), a brain region known to be important for speech perception, is complex, with some regions responding to specific visual stimuli and others to specific auditory stimuli. Using BOLD fMRI, we show that the natural statistics of human speech, in which voices co-occur with mouth movements, are reflected in the neural architecture of the pSTS. Different pSTS regions prefer visually presented faces containing either a moving mouth or moving eyes, but only mouth-preferring regions respond strongly to voices. PMID:28179553

Mouth and Voice: A Relationship between Visual and Auditory Preference in the Human Superior Temporal Sulcus.

PubMed

Zhu, Lin L; Beauchamp, Michael S

2017-03-08

Cortex in and around the human posterior superior temporal sulcus (pSTS) is known to be critical for speech perception. The pSTS responds to both the visual modality (especially biological motion) and the auditory modality (especially human voices). Using fMRI in single subjects with no spatial smoothing, we show that visual and auditory selectivity are linked. Regions of the pSTS were identified that preferred visually presented moving mouths (presented in isolation or as part of a whole face) or moving eyes. Mouth-preferring regions responded strongly to voices and showed a significant preference for vocal compared with nonvocal sounds. In contrast, eye-preferring regions did not respond to either vocal or nonvocal sounds. The converse was also true: regions of the pSTS that showed a significant response to speech or preferred vocal to nonvocal sounds responded more strongly to visually presented mouths than eyes. These findings can be explained by environmental statistics. In natural environments, humans see visual mouth movements at the same time as they hear voices, while there is no auditory accompaniment to visual eye movements. The strength of a voxel's preference for visual mouth movements was strongly correlated with the magnitude of its auditory speech response and its preference for vocal sounds, suggesting that visual and auditory speech features are coded together in small populations of neurons within the pSTS. SIGNIFICANCE STATEMENT Humans interacting face to face make use of auditory cues from the talker's voice and visual cues from the talker's mouth to understand speech. The human posterior superior temporal sulcus (pSTS), a brain region known to be important for speech perception, is complex, with some regions responding to specific visual stimuli and others to specific auditory stimuli. Using BOLD fMRI, we show that the natural statistics of human speech, in which voices co-occur with mouth movements, are reflected in the neural architecture of the pSTS. Different pSTS regions prefer visually presented faces containing either a moving mouth or moving eyes, but only mouth-preferring regions respond strongly to voices. Copyright © 2017 the authors 0270-6474/17/372697-12$15.00/0.

Validation of the Preverbal Visual Assessment (PreViAs) questionnaire.

PubMed

García-Ormaechea, Inés; González, Inmaculada; Duplá, María; Andres, Eva; Pueyo, Victoria

2014-10-01

Visual cognitive integrative functions need to be evaluated by a behavioral assessment, which requires an experienced evaluator. The Preverbal Visual Assessment (PreViAs) questionnaire was designed to evaluate these functions, both in general pediatric population or in children with high risk of visual cognitive problems, through primary caregivers' answers. We aimed to validate the PreViAs questionnaire by comparing caregiver reports with results from a comprehensive clinical protocol. A total of 220 infants (<2 years old) were divided into two groups according to visual development, as determined by the clinical protocol. Their primary caregivers completed the PreViAs questionnaire, which consists of 30 questions related to one or more visual domains: visual attention, visual communication, visual-motor coordination, and visual processing. Questionnaire answers were compared with results of behavioral assessments performed by three pediatric ophthalmologists. Results of the clinical protocol classified 128 infants as having normal visual maturation, and 92 as having abnormal visual maturation. The specificity of PreViAs questionnaire was >80%, and sensitivity was 64%-79%. More than 80% of the infants were correctly classified, and test-retest reliability exceeded 0.9 for all domains. The PreViAs questionnaire is useful to detect abnormal visual maturation in infants from birth to 24months of age. It improves the anamnesis process in infants at risk of visual dysfunctions. Copyright © 2014. Published by Elsevier Ireland Ltd.

Audiovisual Modulation in Mouse Primary Visual Cortex Depends on Cross-Modal Stimulus Configuration and Congruency.

PubMed

Meijer, Guido T; Montijn, Jorrit S; Pennartz, Cyriel M A; Lansink, Carien S

2017-09-06

The sensory neocortex is a highly connected associative network that integrates information from multiple senses, even at the level of the primary sensory areas. Although a growing body of empirical evidence supports this view, the neural mechanisms of cross-modal integration in primary sensory areas, such as the primary visual cortex (V1), are still largely unknown. Using two-photon calcium imaging in awake mice, we show that the encoding of audiovisual stimuli in V1 neuronal populations is highly dependent on the features of the stimulus constituents. When the visual and auditory stimulus features were modulated at the same rate (i.e., temporally congruent), neurons responded with either an enhancement or suppression compared with unisensory visual stimuli, and their prevalence was balanced. Temporally incongruent tones or white-noise bursts included in audiovisual stimulus pairs resulted in predominant response suppression across the neuronal population. Visual contrast did not influence multisensory processing when the audiovisual stimulus pairs were congruent; however, when white-noise bursts were used, neurons generally showed response suppression when the visual stimulus contrast was high whereas this effect was absent when the visual contrast was low. Furthermore, a small fraction of V1 neurons, predominantly those located near the lateral border of V1, responded to sound alone. These results show that V1 is involved in the encoding of cross-modal interactions in a more versatile way than previously thought. SIGNIFICANCE STATEMENT The neural substrate of cross-modal integration is not limited to specialized cortical association areas but extends to primary sensory areas. Using two-photon imaging of large groups of neurons, we show that multisensory modulation of V1 populations is strongly determined by the individual and shared features of cross-modal stimulus constituents, such as contrast, frequency, congruency, and temporal structure. Congruent audiovisual stimulation resulted in a balanced pattern of response enhancement and suppression compared with unisensory visual stimuli, whereas incongruent or dissimilar stimuli at full contrast gave rise to a population dominated by response-suppressing neurons. Our results indicate that V1 dynamically integrates nonvisual sources of information while still attributing most of its resources to coding visual information. Copyright © 2017 the authors 0270-6474/17/378783-14$15.00/0.

Investigating Visually Disabled Students' Attitudes about Physical Education and Sport

ERIC Educational Resources Information Center

Dalbudak, Ibrahim; Gürkan, Alper C.; Yigit, Sih Mehmet; Kargun, Mehmet; Hazar, Gürkan; Dorak, Feridun

2016-01-01

This study aims to investigate visually disabled students', who study in the level of primary education, high school, university, attitudes about physical education and sport in terms of different variables. Totally 100 visually disabled students who are individual and team athletes and study in Izmir, (8 visually disabled athletes study in…

Figure-ground representation and its decay in primary visual cortex.

PubMed

Strother, Lars; Lavell, Cheryl; Vilis, Tutis

2012-04-01

We used fMRI to study figure-ground representation and its decay in primary visual cortex (V1). Human observers viewed a motion-defined figure that gradually became camouflaged by a cluttered background after it stopped moving. V1 showed positive fMRI responses corresponding to the moving figure and negative fMRI responses corresponding to the static background. This positive-negative delineation of V1 "figure" and "background" fMRI responses defined a retinotopically organized figure-ground representation that persisted after the figure stopped moving but eventually decayed. The temporal dynamics of V1 "figure" and "background" fMRI responses differed substantially. Positive "figure" responses continued to increase for several seconds after the figure stopped moving and remained elevated after the figure had disappeared. We propose that the sustained positive V1 "figure" fMRI responses reflected both persistent figure-ground representation and sustained attention to the location of the figure after its disappearance, as did subjects' reports of persistence. The decreasing "background" fMRI responses were relatively shorter-lived and less biased by spatial attention. Our results show that the transition from a vivid figure-ground percept to its disappearance corresponds to the concurrent decay of figure enhancement and background suppression in V1, both of which play a role in form-based perceptual memory.

Immersive viewing engine

NASA Astrophysics Data System (ADS)

Schonlau, William J.

2006-05-01

An immersive viewing engine providing basic telepresence functionality for a variety of application types is presented. Augmented reality, teleoperation and virtual reality applications all benefit from the use of head mounted display devices that present imagery appropriate to the user's head orientation at full frame rates. Our primary application is the viewing of remote environments, as with a camera equipped teleoperated vehicle. The conventional approach where imagery from a narrow field camera onboard the vehicle is presented to the user on a small rectangular screen is contrasted with an immersive viewing system where a cylindrical or spherical format image is received from a panoramic camera on the vehicle, resampled in response to sensed user head orientation and presented via wide field eyewear display, approaching 180 degrees of horizontal field. Of primary interest is the user's enhanced ability to perceive and understand image content, even when image resolution parameters are poor, due to the innate visual integration and 3-D model generation capabilities of the human visual system. A mathematical model for tracking user head position and resampling the panoramic image to attain distortion free viewing of the region appropriate to the user's current head pose is presented and consideration is given to providing the user with stereo viewing generated from depth map information derived using stereo from motion algorithms.

Functionally Specific Oscillatory Activity Correlates between Visual and Auditory Cortex in the Blind

ERIC Educational Resources Information Center

Schepers, Inga M.; Hipp, Joerg F.; Schneider, Till R.; Roder, Brigitte; Engel, Andreas K.

2012-01-01

Many studies have shown that the visual cortex of blind humans is activated in non-visual tasks. However, the electrophysiological signals underlying this cross-modal plasticity are largely unknown. Here, we characterize the neuronal population activity in the visual and auditory cortex of congenitally blind humans and sighted controls in a…

Interference Effects Demonstrate Distinct Roles for Visual and Motor Imagery during the Mental Representation of Human Action

ERIC Educational Resources Information Center

Stevens, J.A.

2005-01-01

Four experiments were completed to characterize the utilization of visual imagery and motor imagery during the mental representation of human action. In Experiment 1, movement time functions for a motor imagery human locomotion task conformed to a speed-accuracy trade-off similar to Fitts' Law, whereas those for a visual imagery object motion task…

Comparison of visual sensitivity to human and object motion in autism spectrum disorder.

PubMed

Kaiser, Martha D; Delmolino, Lara; Tanaka, James W; Shiffrar, Maggie

2010-08-01

Successful social behavior requires the accurate detection of other people's movements. Consistent with this, typical observers demonstrate enhanced visual sensitivity to human movement relative to equally complex, nonhuman movement [e.g., Pinto & Shiffrar, 2009]. A psychophysical study investigated visual sensitivity to human motion relative to object motion in observers with autism spectrum disorder (ASD). Participants viewed point-light depictions of a moving person and, for comparison, a moving tractor and discriminated between coherent and scrambled versions of these stimuli in unmasked and masked displays. There were three groups of participants: young adults with ASD, typically developing young adults, and typically developing children. Across masking conditions, typical observers showed enhanced visual sensitivity to human movement while observers in the ASD group did not. Because the human body is an inherently social stimulus, this result is consistent with social brain theories [e.g., Pelphrey & Carter, 2008; Schultz, 2005] and suggests that the visual systems of individuals with ASD may not be tuned for the detection of socially relevant information such as the presence of another person. Reduced visual sensitivity to human movements could compromise important social behaviors including, for example, gesture comprehension.

Role of feedforward geniculate inputs in the generation of orientation selectivity in the cat's primary visual cortex

PubMed Central

Viswanathan, Sivaram; Jayakumar, Jaikishan; Vidyasagar, Trichur R

2011-01-01

Abstract Neurones of the mammalian primary visual cortex have the remarkable property of being selective for the orientation of visual contours. It has been controversial whether the selectivity arises from intracortical mechanisms, from the pattern of afferent connectivity from lateral geniculate nucleus (LGN) to cortical cells or from the sharpening of a bias that is already present in the responses of many geniculate cells. To investigate this, we employed a variation of an electrical stimulation protocol in the LGN that has been claimed to suppress intracortical inputs and isolate the raw geniculocortical input to a striate cortical cell. Such stimulation led to a sharpening of the orientation sensitivity of geniculate cells themselves and some broadening of cortical orientation selectivity. These findings are consistent with the idea that non-specific inhibition of the signals from LGN cells which exhibit an orientation bias can generate the sharp orientation selectivity of primary visual cortical cells. This obviates the need for an excitatory convergence from geniculate cells whose receptive fields are arranged along a row in visual space as in the classical model and provides a framework for orientation sensitivity originating in the retina and getting sharpened through inhibition at higher levels of the visual pathway. PMID:21486788

How the mechanisms of long-term synaptic potentiation and depression serve experience-dependent plasticity in primary visual cortex

PubMed Central

Cooke, Sam F.; Bear, Mark F.

2014-01-01

Donald Hebb chose visual learning in primary visual cortex (V1) of the rodent to exemplify his theories of how the brain stores information through long-lasting homosynaptic plasticity. Here, we revisit V1 to consider roles for bidirectional ‘Hebbian’ plasticity in the modification of vision through experience. First, we discuss the consequences of monocular deprivation (MD) in the mouse, which have been studied by many laboratories over many years, and the evidence that synaptic depression of excitatory input from the thalamus is a primary contributor to the loss of visual cortical responsiveness to stimuli viewed through the deprived eye. Second, we describe a less studied, but no less interesting form of plasticity in the visual cortex known as stimulus-selective response potentiation (SRP). SRP results in increases in the response of V1 to a visual stimulus through repeated viewing and bears all the hallmarks of perceptual learning. We describe evidence implicating an important role for potentiation of thalamo-cortical synapses in SRP. In addition, we present new data indicating that there are some features of this form of plasticity that cannot be fully accounted for by such feed-forward Hebbian plasticity, suggesting contributions from intra-cortical circuit components. PMID:24298166

The primary visual cortex in the neural circuit for visual orienting

NASA Astrophysics Data System (ADS)

Zhaoping, Li

The primary visual cortex (V1) is traditionally viewed as remote from influencing brain's motor outputs. However, V1 provides the most abundant cortical inputs directly to the sensory layers of superior colliculus (SC), a midbrain structure to command visual orienting such as shifting gaze and turning heads. I will show physiological, anatomical, and behavioral data suggesting that V1 transforms visual input into a saliency map to guide a class of visual orienting that is reflexive or involuntary. In particular, V1 receives a retinotopic map of visual features, such as orientation, color, and motion direction of local visual inputs; local interactions between V1 neurons perform a local-to-global computation to arrive at a saliency map that highlights conspicuous visual locations by higher V1 responses. The conspicuous location are usually, but not always, where visual input statistics changes. The population V1 outputs to SC, which is also retinotopic, enables SC to locate, by lateral inhibition between SC neurons, the most salient location as the saccadic target. Experimental tests of this hypothesis will be shown. Variations of the neural circuit for visual orienting across animal species, with more or less V1 involvement, will be discussed. Supported by the Gatsby Charitable Foundation.

Progressive Decrease of Peripapillary Angioflow Vessel Density During Structural and Visual Field Progression in Early Primary Open-angle Glaucoma.

PubMed

Holló, Gábor

2017-07-01

To present a case of early primary open-angle glaucoma in which retinal nerve fiber layer thickness (RNFLT), ganglion cell complex (GCC), and visual field progression were accompanied with significant progression of peripapillary angioflow vessel density (PAFD) measured with optical coherence tomographic angiography. A 68-year-old female patient who was under topical intraocular pressure (IOP) lowering medication for 20 years for ocular hypertension of the right and preperimetric primary open-angle glaucoma of the left eye (with reproducible inferotemporal and superotemporal neuroretinal rim and RNFL loss) was prospectively imaged with the AngioVue OCT for RNFLT, GCC thickness, and PAFD, and investigated with the Octopus Normal G2 visual field test on the same days at 6-month intervals for 18 months, while the IOP of the left eye escaped from control. IOP of the left eye fluctuated between 14 and 30 mm Hg in the study period. RNFLT, GCC thickness, and peripapillary PAFD all decreased significantly (linear regression analysis, P=0.030, 0.040, and 0.020, respectively), and a significant 2.1 dB/y progression was seen for a superior visual field cluster. The RNFLT, peripapillary PAFD, and visual field of the right eye remained normal and unchanged. In our case IOP elevation, glaucomatous visual field conversion, and structural progression were accompanied with significant progressive decrease of peripapillary PAFD. The simultaneous thinning of RNFLT and GCC and decrease of peripapillary PAFD suggest that PAFD may potentially be an additional indicator of early progression in primary open-angle glaucoma.

Assessment of Visual Status of the Aeta, a Hunter-Gatherer Population of the Philippines (An AOS Thesis)

PubMed Central

Allingham, R. Rand

2008-01-01

Purpose A screening study was performed to assess levels of visual impairment and blindness among a representative sample of older members of the Aeta, an indigenous hunter-gatherer population living on the island of Luzon in the Philippines. Methods Unrelated older Aeta couples were randomly invited to participate in a visual screening study. All consented individuals had ocular history, medical history, complete ophthalmic examination, height, weight, and blood pressure taken. Results A total of 225 individuals were screened from 4 villages. Visual acuity, both uncorrected and pinhole corrected, was significantly worse among older vs younger age-groups for women, men, and when combined (P < .001). Visual impairment was present in 48% of uncorrected and 43% of pinhole corrected eyes in the oldest age-group. Six percent of the screened population was bilaterally blind. The major causes of blindness were readily treatable. The most common etiologies as a proportion of blind eyes were cataract (66%), refractive error (20%), and trauma (7%). No cases of primary open-angle, primary angle-closure, or exfoliation glaucoma were observed in this population. Discussion Visual impairment and blindness were common in the Aeta population. Primary forms of glaucoma, a major cause of blindness found in most population-based studies, were not observed. The absence of primary glaucoma in this population may reflect random sampling error. However, based on similar findings in the Australian Aborigine, this raises the possibility that these two similar populations may share genetic and/or environmental factors that are protective for glaucoma.. PMID:19277240

Is attentional prioritisation of infant faces unique in humans?: Comparative demonstrations by modified dot-probe task in monkeys.

PubMed

Koda, Hiroki; Sato, Anna; Kato, Akemi

2013-09-01

Humans innately perceive infantile features as cute. The ethologist Konrad Lorenz proposed that the infantile features of mammals and birds, known as the baby schema (kindchenschema), motivate caretaking behaviour. As biologically relevant stimuli, newborns are likely to be processed specially in terms of visual attention, perception, and cognition. Recent demonstrations on human participants have shown visual attentional prioritisation to newborn faces (i.e., newborn faces capture visual attention). Although characteristics equivalent to those found in the faces of human infants are found in nonhuman primates, attentional capture by newborn faces has not been tested in nonhuman primates. We examined whether conspecific newborn faces captured the visual attention of two Japanese monkeys using a target-detection task based on dot-probe tasks commonly used in human visual attention studies. Although visual cues enhanced target detection in subject monkeys, our results, unlike those for humans, showed no evidence of an attentional prioritisation for newborn faces by monkeys. Our demonstrations showed the validity of dot-probe task for visual attention studies in monkeys and propose a novel approach to bridge the gap between human and nonhuman primate social cognition research. This suggests that attentional capture by newborn faces is not common to macaques, but it is unclear if nursing experiences influence their perception and recognition of infantile appraisal stimuli. We need additional comparative studies to reveal the evolutionary origins of baby-schema perception and recognition. Copyright © 2013 Elsevier B.V. All rights reserved.

Estimation of bio-signal based on human motion for integrated visualization of daily-life.

PubMed

Umetani, Tomohiro; Matsukawa, Tsuyoshi; Yokoyama, Kiyoko

2007-01-01

This paper describes a method for the estimation of bio-signals based on human motion in daily life for an integrated visualization system. The recent advancement of computers and measurement technology has facilitated the integrated visualization of bio-signals and human motion data. It is desirable to obtain a method to understand the activities of muscles based on human motion data and evaluate the change in physiological parameters according to human motion for visualization applications. We suppose that human motion is generated by the activities of muscles reflected from the brain to bio-signals such as electromyograms. This paper introduces a method for the estimation of bio-signals based on neural networks. This method can estimate the other physiological parameters based on the same procedure. The experimental results show the feasibility of the proposed method.

Neural correlates of the LSD experience revealed by multimodal neuroimaging.

PubMed

Carhart-Harris, Robin L; Muthukumaraswamy, Suresh; Roseman, Leor; Kaelen, Mendel; Droog, Wouter; Murphy, Kevin; Tagliazucchi, Enzo; Schenberg, Eduardo E; Nest, Timothy; Orban, Csaba; Leech, Robert; Williams, Luke T; Williams, Tim M; Bolstridge, Mark; Sessa, Ben; McGonigle, John; Sereno, Martin I; Nichols, David; Hellyer, Peter J; Hobden, Peter; Evans, John; Singh, Krish D; Wise, Richard G; Curran, H Valerie; Feilding, Amanda; Nutt, David J

2016-04-26

Lysergic acid diethylamide (LSD) is the prototypical psychedelic drug, but its effects on the human brain have never been studied before with modern neuroimaging. Here, three complementary neuroimaging techniques: arterial spin labeling (ASL), blood oxygen level-dependent (BOLD) measures, and magnetoencephalography (MEG), implemented during resting state conditions, revealed marked changes in brain activity after LSD that correlated strongly with its characteristic psychological effects. Increased visual cortex cerebral blood flow (CBF), decreased visual cortex alpha power, and a greatly expanded primary visual cortex (V1) functional connectivity profile correlated strongly with ratings of visual hallucinations, implying that intrinsic brain activity exerts greater influence on visual processing in the psychedelic state, thereby defining its hallucinatory quality. LSD's marked effects on the visual cortex did not significantly correlate with the drug's other characteristic effects on consciousness, however. Rather, decreased connectivity between the parahippocampus and retrosplenial cortex (RSC) correlated strongly with ratings of "ego-dissolution" and "altered meaning," implying the importance of this particular circuit for the maintenance of "self" or "ego" and its processing of "meaning." Strong relationships were also found between the different imaging metrics, enabling firmer inferences to be made about their functional significance. This uniquely comprehensive examination of the LSD state represents an important advance in scientific research with psychedelic drugs at a time of growing interest in their scientific and therapeutic value. The present results contribute important new insights into the characteristic hallucinatory and consciousness-altering properties of psychedelics that inform on how they can model certain pathological states and potentially treat others.

Neural correlates of the LSD experience revealed by multimodal neuroimaging

PubMed Central

Carhart-Harris, Robin L.; Muthukumaraswamy, Suresh; Roseman, Leor; Kaelen, Mendel; Droog, Wouter; Murphy, Kevin; Tagliazucchi, Enzo; Schenberg, Eduardo E.; Nest, Timothy; Orban, Csaba; Leech, Robert; Williams, Luke T.; Williams, Tim M.; Bolstridge, Mark; Sessa, Ben; McGonigle, John; Sereno, Martin I.; Nichols, David; Hobden, Peter; Evans, John; Singh, Krish D.; Wise, Richard G.; Curran, H. Valerie; Feilding, Amanda; Nutt, David J.

2016-01-01

Lysergic acid diethylamide (LSD) is the prototypical psychedelic drug, but its effects on the human brain have never been studied before with modern neuroimaging. Here, three complementary neuroimaging techniques: arterial spin labeling (ASL), blood oxygen level-dependent (BOLD) measures, and magnetoencephalography (MEG), implemented during resting state conditions, revealed marked changes in brain activity after LSD that correlated strongly with its characteristic psychological effects. Increased visual cortex cerebral blood flow (CBF), decreased visual cortex alpha power, and a greatly expanded primary visual cortex (V1) functional connectivity profile correlated strongly with ratings of visual hallucinations, implying that intrinsic brain activity exerts greater influence on visual processing in the psychedelic state, thereby defining its hallucinatory quality. LSD’s marked effects on the visual cortex did not significantly correlate with the drug’s other characteristic effects on consciousness, however. Rather, decreased connectivity between the parahippocampus and retrosplenial cortex (RSC) correlated strongly with ratings of “ego-dissolution” and “altered meaning,” implying the importance of this particular circuit for the maintenance of “self” or “ego” and its processing of “meaning.” Strong relationships were also found between the different imaging metrics, enabling firmer inferences to be made about their functional significance. This uniquely comprehensive examination of the LSD state represents an important advance in scientific research with psychedelic drugs at a time of growing interest in their scientific and therapeutic value. The present results contribute important new insights into the characteristic hallucinatory and consciousness-altering properties of psychedelics that inform on how they can model certain pathological states and potentially treat others. PMID:27071089

A graph-theoretical analysis algorithm for quantifying the transition from sensory input to motor output by an emotional stimulus.

PubMed

Karmonik, Christof; Fung, Steve H; Dulay, M; Verma, A; Grossman, Robert G

2013-01-01

Graph-theoretical analysis algorithms have been used for identifying subnetworks in the human brain during the Default Mode State. Here, these methods are expanded to determine the interaction of the sensory and the motor subnetworks during the performance of an approach-avoidance paradigm utilizing the correlation strength between the signal intensity time courses as measure of synchrony. From functional magnetic resonance imaging (fMRI) data of 9 healthy volunteers, two signal time courses, one from the primary visual cortex (sensory input) and one from the motor cortex (motor output) were identified and a correlation difference map was calculated. Graph networks were created from this map and visualized with spring-embedded layouts and 3D layouts in the original anatomical space. Functional clusters in these networks were identified with the MCODE clustering algorithm. Interactions between the sensory sub-network and the motor sub-network were quantified through the interaction strengths of these clusters. The percentages of interactions involving the visual cortex ranged from 85 % to 18 % and the motor cortex ranged from 40 % to 9 %. Other regions with high interactions were: frontal cortex (19 ± 18 %), insula (17 ± 22 %), cuneus (16 ± 15 %), supplementary motor area (SMA, 11 ± 18 %) and subcortical regions (11 ± 10 %). Interactions between motor cortex, SMA and visual cortex accounted for 12 %, between visual cortex and cuneus for 8 % and between motor cortex, SMA and cuneus for 6 % of all interactions. These quantitative findings are supported by the visual impressions from the 2D and 3D network layouts.

UAV visual signature suppression via adaptive materials

NASA Astrophysics Data System (ADS)

Barrett, Ron; Melkert, Joris

2005-05-01

Visual signature suppression (VSS) methods for several classes of aircraft from WWII on are examined and historically summarized. This study shows that for some classes of uninhabited aerial vehicles (UAVs), primary mission threats do not stem from infrared or radar signatures, but from the amount that an aircraft visually stands out against the sky. The paper shows that such visual mismatch can often jeopardize mission success and/or induce the destruction of the entire aircraft. A psycho-physioptical study was conducted to establish the definition and benchmarks of a Visual Cross Section (VCS) for airborne objects. This study was centered on combining the effects of size, shape, color and luminosity or effective illumance (EI) of a given aircraft to arrive at a VCS. A series of tests were conducted with a 6.6ft (2m) UAV which was fitted with optically adaptive electroluminescent sheets at altitudes of up to 1000 ft (300m). It was shown that with proper tailoring of the color and luminosity, the VCS of the aircraft dropped from more than 4,200cm2 to less than 1.8cm2 at 100m (the observed lower limit of the 20-20 human eye in this study). In laypersons terms this indicated that the UAV essentially "disappeared". This study concludes with an assessment of the weight and volume impact of such a Visual Suppression System (VSS) on the UAV, showing that VCS levels on this class UAV can be suppressed to below 1.8cm2 for aircraft gross weight penalties of only 9.8%.

Posttraining transcranial magnetic stimulation of striate cortex disrupts consolidation early in visual skill learning.

PubMed

De Weerd, Peter; Reithler, Joel; van de Ven, Vincent; Been, Marin; Jacobs, Christianne; Sack, Alexander T

2012-02-08

Practice-induced improvements in skilled performance reflect "offline " consolidation processes extending beyond daily training sessions. According to visual learning theories, an early, fast learning phase driven by high-level areas is followed by a late, asymptotic learning phase driven by low-level, retinotopic areas when higher resolution is required. Thus, low-level areas would not contribute to learning and offline consolidation until late learning. Recent studies have challenged this notion, demonstrating modified responses to trained stimuli in primary visual cortex (V1) and offline activity after very limited training. However, the behavioral relevance of modified V1 activity for offline consolidation of visual skill memory in V1 after early training sessions remains unclear. Here, we used neuronavigated transcranial magnetic stimulation (TMS) directed to a trained retinotopic V1 location to test for behaviorally relevant consolidation in human low-level visual cortex. Applying TMS to the trained V1 location within 45 min of the first or second training session strongly interfered with learning, as measured by impaired performance the next day. The interference was conditional on task context and occurred only when training in the location targeted by TMS was followed by training in a second location before TMS. In this condition, high-level areas may become coupled to the second location and uncoupled from the previously trained low-level representation, thereby rendering consolidation vulnerable to interference. Our data show that, during the earliest phases of skill learning in the lowest-level visual areas, a behaviorally relevant form of consolidation exists of which the robustness is controlled by high-level, contextual factors.

The direct, not V1-mediated, functional influence between the thalamus and middle temporal complex in the human brain is modulated by the speed of visual motion.

PubMed

Gaglianese, A; Costagli, M; Ueno, K; Ricciardi, E; Bernardi, G; Pietrini, P; Cheng, K

2015-01-22

The main visual pathway that conveys motion information to the middle temporal complex (hMT+) originates from the primary visual cortex (V1), which, in turn, receives spatial and temporal features of the perceived stimuli from the lateral geniculate nucleus (LGN). In addition, visual motion information reaches hMT+ directly from the thalamus, bypassing the V1, through a direct pathway. We aimed at elucidating whether this direct route between LGN and hMT+ represents a 'fast lane' reserved to high-speed motion, as proposed previously, or it is merely involved in processing motion information irrespective of speeds. We evaluated functional magnetic resonance imaging (fMRI) responses elicited by moving visual stimuli and applied connectivity analyses to investigate the effect of motion speed on the causal influence between LGN and hMT+, independent of V1, using the Conditional Granger Causality (CGC) in the presence of slow and fast visual stimuli. Our results showed that at least part of the visual motion information from LGN reaches hMT+, bypassing V1, in response to both slow and fast motion speeds of the perceived stimuli. We also investigated whether motion speeds have different effects on the connections between LGN and functional subdivisions within hMT+: direct connections between LGN and MT-proper carry mainly slow motion information, while connections between LGN and MST carry mainly fast motion information. The existence of a parallel pathway that connects the LGN directly to hMT+ in response to both slow and fast speeds may explain why MT and MST can still respond in the presence of V1 lesions. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Endogenous Sequential Cortical Activity Evoked by Visual Stimuli

PubMed Central

Miller, Jae-eun Kang; Hamm, Jordan P.; Jackson, Jesse; Yuste, Rafael

2015-01-01

Although the functional properties of individual neurons in primary visual cortex have been studied intensely, little is known about how neuronal groups could encode changing visual stimuli using temporal activity patterns. To explore this, we used in vivo two-photon calcium imaging to record the activity of neuronal populations in primary visual cortex of awake mice in the presence and absence of visual stimulation. Multidimensional analysis of the network activity allowed us to identify neuronal ensembles defined as groups of cells firing in synchrony. These synchronous groups of neurons were themselves activated in sequential temporal patterns, which repeated at much higher proportions than chance and were triggered by specific visual stimuli such as natural visual scenes. Interestingly, sequential patterns were also present in recordings of spontaneous activity without any sensory stimulation and were accompanied by precise firing sequences at the single-cell level. Moreover, intrinsic dynamics could be used to predict the occurrence of future neuronal ensembles. Our data demonstrate that visual stimuli recruit similar sequential patterns to the ones observed spontaneously, consistent with the hypothesis that already existing Hebbian cell assemblies firing in predefined temporal sequences could be the microcircuit substrate that encodes visual percepts changing in time. PMID:26063915

Development of the Preverbal Visual Assessment (PreViAs) questionnaire.

PubMed

Pueyo, Victoria; García-Ormaechea, Inés; González, Inmaculada; Ferrer, Concepción; de la Mata, Guillermo; Duplá, María; Orós, Pedro; Andres, Eva

2014-04-01

Visual cognitive functions of preverbal infants are evaluated by means of a behavioral assessment. Parents or primary caregivers may be appropriate to certify the acquisition of certain abilities. To develop the PreViAs (Preverbal Visual Assessment) questionnaire to assess visual behavior of infants under 24 months of age and to assess the normative outcomes for each item at each age. The process was divided into three phases: scale development (items and domains generation), pilot testing, and exploratory analysis. The final version of the PreViAs questionnaire consisted of 30 items, each related to one or more of four domains (visual attention, visual communication, visual-motor coordination, and visual processing). For the exploratory analysis, 298 children (159 boys and 139 girls) were recruited. Their ages ranged from 0.1 to 24 months (mean, 11.2 months). Internal consistency of the questionnaire was high for all domains (Cronbach's α coefficients of 0.85-0.94). The PreViAs questionnaire is a useful scale for assessing visual cognitive abilities of infants under 24 months of age. It is easy and feasible to complete by primary caregivers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Visual Environments for CFD Research

NASA Technical Reports Server (NTRS)

Watson, Val; George, Michael W. (Technical Monitor)

1994-01-01

This viewgraph presentation gives an overview of the visual environments for computational fluid dynamics (CFD) research. It includes details on critical needs from the future computer environment, features needed to attain this environment, prospects for changes in and the impact of the visualization revolution on the human-computer interface, human processing capabilities, limits of personal environment and the extension of that environment with computers. Information is given on the need for more 'visual' thinking (including instances of visual thinking), an evaluation of the alternate approaches for and levels of interactive computer graphics, a visual analysis of computational fluid dynamics, and an analysis of visualization software.

The Effects of Context and Attention on Spiking Activity in Human Early Visual Cortex.

PubMed

Self, Matthew W; Peters, Judith C; Possel, Jessy K; Reithler, Joel; Goebel, Rainer; Ris, Peterjan; Jeurissen, Danique; Reddy, Leila; Claus, Steven; Baayen, Johannes C; Roelfsema, Pieter R

2016-03-01

Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive fields with tunings for contrast, orientation, spatial frequency, and size, similar to those reported in the macaque. We also observed pronounced gamma oscillations in the local-field potential that could be used to estimate the underlying spiking response properties. Spiking responses were modulated by visual context and attention. We observed orientation-tuned surround suppression: responses were suppressed by image regions with a uniform orientation and enhanced by orientation contrast. Additionally, responses were enhanced on regions that perceptually segregated from the background, indicating that neurons in the human visual cortex are sensitive to figure-ground structure. Spiking responses were also modulated by object-based attention. When the patient mentally traced a curve through the neurons' receptive fields, the accompanying shift of attention enhanced neuronal activity. These results demonstrate that the tuning properties of cells in the human early visual cortex are similar to those in the macaque and that responses can be modulated by both contextual factors and behavioral relevance. Our results, therefore, imply that the macaque visual system is an excellent model for the human visual cortex.

A simpler primate brain: the visual system of the marmoset monkey

PubMed Central

Solomon, Samuel G.; Rosa, Marcello G. P.

2014-01-01

Humans are diurnal primates with high visual acuity at the center of gaze. Although primates share many similarities in the organization of their visual centers with other mammals, and even other species of vertebrates, their visual pathways also show unique features, particularly with respect to the organization of the cerebral cortex. Therefore, in order to understand some aspects of human visual function, we need to study non-human primate brains. Which species is the most appropriate model? Macaque monkeys, the most widely used non-human primates, are not an optimal choice in many practical respects. For example, much of the macaque cerebral cortex is buried within sulci, and is therefore inaccessible to many imaging techniques, and the postnatal development and lifespan of macaques are prohibitively long for many studies of brain maturation, plasticity, and aging. In these and several other respects the marmoset, a small New World monkey, represents a more appropriate choice. Here we review the visual pathways of the marmoset, highlighting recent work that brings these advantages into focus, and identify where additional work needs to be done to link marmoset brain organization to that of macaques and humans. We will argue that the marmoset monkey provides a good subject for studies of a complex visual system, which will likely allow an important bridge linking experiments in animal models to humans. PMID:25152716

The Effects of Context and Attention on Spiking Activity in Human Early Visual Cortex

PubMed Central

Reithler, Joel; Goebel, Rainer; Ris, Peterjan; Jeurissen, Danique; Reddy, Leila; Claus, Steven; Baayen, Johannes C.; Roelfsema, Pieter R.

2016-01-01

Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive fields with tunings for contrast, orientation, spatial frequency, and size, similar to those reported in the macaque. We also observed pronounced gamma oscillations in the local-field potential that could be used to estimate the underlying spiking response properties. Spiking responses were modulated by visual context and attention. We observed orientation-tuned surround suppression: responses were suppressed by image regions with a uniform orientation and enhanced by orientation contrast. Additionally, responses were enhanced on regions that perceptually segregated from the background, indicating that neurons in the human visual cortex are sensitive to figure-ground structure. Spiking responses were also modulated by object-based attention. When the patient mentally traced a curve through the neurons’ receptive fields, the accompanying shift of attention enhanced neuronal activity. These results demonstrate that the tuning properties of cells in the human early visual cortex are similar to those in the macaque and that responses can be modulated by both contextual factors and behavioral relevance. Our results, therefore, imply that the macaque visual system is an excellent model for the human visual cortex. PMID:27015604

Human Factors Assessment of Vibration Effects on Visual Performance During Launch

NASA Technical Reports Server (NTRS)

Holden, Kritina

2009-01-01

The Human Factors Assessment of Vibration Effects on Visual Performance During Launch (Visual Performance) investigation will determine visual performance limits during operational vibration and g-loads on the Space Shuttle, specifically through the determination of minimum readable font size during ascent using planned Orion display formats. Research Summary: The aim of the Human Factors Assessment of Vibration Effects on Visual Performance during Launch (Visual Performance) investigation is to provide supplementary data to that collected by the Thrust Oscillation Seat Detailed Technical Objective (DTO) 695 (Crew Seat DTO) which will measure seat acceleration and vibration from one flight deck and two middeck seats during ascent. While the Crew Seat DTO data alone are important in terms of providing a measure of vibration and g-loading, human performance data are required to fully interpret the operational consequences of the vibration values collected during Space Shuttle ascent. During launch, crewmembers will be requested to view placards with varying font sizes and indicate the minimum readable size. In combination with the Crew Seat DTO, the Visual Performance investigation will: Provide flight-validated evidence that will be used to establish vibration limits for visual performance during combined vibration and linear g-loading. o Provide flight data as inputs to ongoing ground-based simulations, which will further validate crew visual performance under vibration loading in a controlled environment. o Provide vibration and performance metrics to help validate procedures for ground tests and analyses of seats, suits, displays and controls, and human-in-the-loop performance.

Overview of Human-Centric Space Situational Awareness Science and Technology

DTIC Science & Technology

2012-09-01

AGI), the developers of Satellite Tool Kit ( STK ), has provided demonstrations of innovative SSA visualization concepts that take advantage of the...needs inherent with SSA. RH has conducted CTAs and developed work-centered human-computer interfaces, visualizations , and collaboration technologies...all end users. RH’s Battlespace Visualization Branch researches methods to exploit the visual channel primarily to improve decision making and

Preliminary Investigation of Visual Attention to Human Figures in Photographs: Potential Considerations for the Design of Aided AAC Visual Scene Displays

ERIC Educational Resources Information Center

Wilkinson, Krista M.; Light, Janice

2011-01-01

Purpose: Many individuals with complex communication needs may benefit from visual aided augmentative and alternative communication systems. In visual scene displays (VSDs), language concepts are embedded into a photograph of a naturalistic event. Humans play a central role in communication development and might be important elements in VSDs.…

Object-Based Visual Attention in 8-Month-Old Infants: Evidence from an Eye-Tracking Study

ERIC Educational Resources Information Center

Bulf, Hermann; Valenza, Eloisa

2013-01-01

Visual attention is one of the infant's primary tools for gathering relevant information from the environment for further processing and learning. The space-based component of visual attention in infants has been widely investigated; however, the object-based component of visual attention has received scarce interest. This scarcity is…

Cortical metabolic activity matches the pattern of visual suppression in strabismus.

PubMed

Adams, Daniel L; Economides, John R; Sincich, Lawrence C; Horton, Jonathan C

2013-02-27

When an eye becomes deviated in early childhood, a person does not experience double vision, although the globes are aimed at different targets. The extra image is prevented from reaching perception in subjects with alternating exotropia by suppression of each eye's peripheral temporal retina. To test the impact of visual suppression on neuronal activity in primary (striate) visual cortex, the pattern of cytochrome oxidase (CO) staining was examined in four macaques raised with exotropia by disinserting the medial rectus muscles shortly following birth. No ocular dominance columns were visible in opercular cortex, where the central visual field is represented, indicating that signals coming from the central retina in each eye were perceived. However, the border strips at the edges of ocular dominance columns appeared pale, reflecting a loss of activity in binocular cells from disruption of fusion. In calcarine cortex, where the peripheral visual field is represented, there were alternating pale and dark bands resembling ocular dominance columns. To interpret the CO staining pattern, [(3)H]proline was injected into the right eye in two monkeys. In the right calcarine cortex, the pale CO columns matched the labeled proline columns of the right eye. In the left calcarine cortex, the pale CO columns overlapped the unlabeled columns of the left eye in the autoradiograph. Therefore, metabolic activity was reduced in the ipsilateral eye's ocular dominance columns which serve peripheral temporal retina, in a fashion consistent with the topographic organization of suppression scotomas in humans with exotropia.

Evolutionary relevance facilitates visual information processing.

PubMed

Jackson, Russell E; Calvillo, Dusti P

2013-11-03

Visual search of the environment is a fundamental human behavior that perceptual load affects powerfully. Previously investigated means for overcoming the inhibitions of high perceptual load, however, generalize poorly to real-world human behavior. We hypothesized that humans would process evolutionarily relevant stimuli more efficiently than evolutionarily novel stimuli, and evolutionary relevance would mitigate the repercussions of high perceptual load during visual search. Animacy is a significant component to evolutionary relevance of visual stimuli because perceiving animate entities is time-sensitive in ways that pose significant evolutionary consequences. Participants completing a visual search task located evolutionarily relevant and animate objects fastest and with the least impact of high perceptual load. Evolutionarily novel and inanimate objects were located slowest and with the highest impact of perceptual load. Evolutionary relevance may importantly affect everyday visual information processing.

Visual Information Present in Infragranular Layers of Mouse Auditory Cortex.

PubMed

Morrill, Ryan J; Hasenstaub, Andrea R

2018-03-14

The cerebral cortex is a major hub for the convergence and integration of signals from across the sensory modalities; sensory cortices, including primary regions, are no exception. Here we show that visual stimuli influence neural firing in the auditory cortex of awake male and female mice, using multisite probes to sample single units across multiple cortical layers. We demonstrate that visual stimuli influence firing in both primary and secondary auditory cortex. We then determine the laminar location of recording sites through electrode track tracing with fluorescent dye and optogenetic identification using layer-specific markers. Spiking responses to visual stimulation occur deep in auditory cortex and are particularly prominent in layer 6. Visual modulation of firing rate occurs more frequently at areas with secondary-like auditory responses than those with primary-like responses. Auditory cortical responses to drifting visual gratings are not orientation-tuned, unlike visual cortex responses. The deepest cortical layers thus appear to be an important locus for cross-modal integration in auditory cortex. SIGNIFICANCE STATEMENT The deepest layers of the auditory cortex are often considered its most enigmatic, possessing a wide range of cell morphologies and atypical sensory responses. Here we show that, in mouse auditory cortex, these layers represent a locus of cross-modal convergence, containing many units responsive to visual stimuli. Our results suggest that this visual signal conveys the presence and timing of a stimulus rather than specifics about that stimulus, such as its orientation. These results shed light on both how and what types of cross-modal information is integrated at the earliest stages of sensory cortical processing. Copyright © 2018 the authors 0270-6474/18/382854-09$15.00/0.

Relating Standardized Visual Perception Measures to Simulator Visual System Performance

NASA Technical Reports Server (NTRS)

Kaiser, Mary K.; Sweet, Barbara T.

2013-01-01

Human vision is quantified through the use of standardized clinical vision measurements. These measurements typically include visual acuity (near and far), contrast sensitivity, color vision, stereopsis (a.k.a. stereo acuity), and visual field periphery. Simulator visual system performance is specified in terms such as brightness, contrast, color depth, color gamut, gamma, resolution, and field-of-view. How do these simulator performance characteristics relate to the perceptual experience of the pilot in the simulator? In this paper, visual acuity and contrast sensitivity will be related to simulator visual system resolution, contrast, and dynamic range; similarly, color vision will be related to color depth/color gamut. Finally, we will consider how some characteristics of human vision not typically included in current clinical assessments could be used to better inform simulator requirements (e.g., relating dynamic characteristics of human vision to update rate and other temporal display characteristics).

Information processing occurs via critical avalanches in a model of the primary visual cortex

NASA Astrophysics Data System (ADS)

Bortolotto, G. S.; Girardi-Schappo, M.; Gonsalves, J. J.; Pinto, L. T.; Tragtenberg, M. H. R.

2016-01-01

We study a new biologically motivated model for the Macaque monkey primary visual cortex which presents power-law avalanches after a visual stimulus. The signal propagates through all the layers of the model via avalanches that depend on network structure and synaptic parameter. We identify four different avalanche profiles as a function of the excitatory postsynaptic potential. The avalanches follow a size-duration scaling relation and present critical exponents that match experiments. The structure of the network gives rise to a regime of two characteristic spatial scales, one of which vanishes in the thermodynamic limit.

Are Males and Females Still Portrayed Stereotypically? Visual Analyses of Gender in Two Hong Kong Primary English Language Textbook Series

ERIC Educational Resources Information Center

Yang, Chi Cheung Ruby

2016-01-01

The present study examines how gender is represented in the visuals (or illustrations) of two English Language textbook series used in most primary schools in Hong Kong. Instead of conducting frequency counts of the occurrence of male and female characters in illustrations, or the spheres of activities they engaged in as in many previous textbook…

Surface-Streamline Flow Visualization

NASA Technical Reports Server (NTRS)

Langston, L.; Boyle, M.

1985-01-01

Matrix of ink dots covers matte surface of polyester drafting film. Film placed against wind-tunnel wall. Layer of methyl salicylate (oil of wintergreen) sprayed over dotted area. Ink dot streaklines show several characteristics of flow, including primary saddle point of separations, primary horseshoe vortex and smaller vortex at cylinder/ endwall junction. Surface streamline flow visualization technique suitable for use in low-speed windtunnels or other low-speed gas flows.

[Effects of nootropic agents on visual functions and lacrimal antioxidative activity in patients with primary open-angle glaucoma].

PubMed

Davydova, N G; Kuznetsova, T P; Borisova, S A; Abdulkadyrova, M Zh

2006-01-01

The paper presents the results of an investigation of the effect of the nootropic agents pantogam and nooclerine on visual functions in patients with primary open-angle glaucoma. These agents have been found to have a beneficial effect on the functional activity of the retina and optic nerve, light sensitivity, hemo- and hydrodynamics of the eye.

Contribution of Visualized Phrases on Word Using Skill

ERIC Educational Resources Information Center

Batur, Zekerya

2013-01-01

In this study it was researched whether visualized proverbs, idioms and epigrams have effect of primary school 3rd, 5th and 7th grade students' speaking skills. The study was executed in spring semester of the academic year of 2010-2011, with 30 students studying at primary school in 3rd, 5th and 7th grade. The students who participated in the…

Art, Illusion and the Visual System.

ERIC Educational Resources Information Center

Livingstone, Margaret S.

1988-01-01

Describes the three part system of human vision. Explores the anatomical arrangement of the vision system from the eyes to the brain. Traces the path of various visual signals to their interpretations by the brain. Discusses human visual perception and its implications in art and design. (CW)

Treatment of Advanced Glaucoma Study: a multicentre randomised controlled trial comparing primary medical treatment with primary trabeculectomy for people with newly diagnosed advanced glaucoma-study protocol.

PubMed

King, Anthony J; Fernie, Gordon; Azuara-Blanco, Augusto; Burr, Jennifer M; Garway-Heath, Ted; Sparrow, John M; Vale, Luke; Hudson, Jemma; MacLennan, Graeme; McDonald, Alison; Barton, Keith; Norrie, John

2017-10-26

Presentation with advanced glaucoma is the major risk factor for lifetime blindness. Effective intervention at diagnosis is expected to minimise risk of further visual loss in this group of patients. To compare clinical and cost-effectiveness of primary medical management compared with primary surgery for people presenting with advanced open-angle glaucoma (OAG). Design : A prospective, pragmatic multicentre randomised controlled trial (RCT). Twenty-seven UK hospital eye services. Four hundred and forty patients presenting with advanced OAG, according to the Hodapp-Parish-Anderson classification of visual field loss. Participants will be randomised to medical treatment or augmented trabeculectomy (1:1 allocation minimised by centre and presence of advanced disease in both eyes). The primary outcome is vision-related quality of life measured by the National Eye Institute-Visual Function Questionnaire-25 at 24 months. Secondary outcomes include generic EQ-5D-5L, Health Utility Index-3 and glaucoma-related health status (Glaucoma Utility Index), patient experience, visual field measured by mean deviation value, logarithm of the mean angle of resolution visual acuity, intraocular pressure, adverse events, standards for driving and eligibility for blind certification. Incremental cost per quality-adjusted life-year (QALY) based on EQ-5D-5L and glaucoma profile instrument will be estimated. The study will report the comparative effectiveness and cost-effectiveness of medical treatment against augmented trabeculectomy in patients presenting with advanced glaucoma in terms of patient-reported health and visual function, clinical outcomes and incremental cost per QALY at 2 years. Treatment of Advanced Glaucoma Study will be the first RCT reporting outcomes from the perspective of those with advanced glaucoma. ISRCTN56878850, Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

A correlative and quantitative imaging approach enabling characterization of primary cell-cell communication: Case of human CD4+ T cell-macrophage immunological synapses.

PubMed

Kasprowicz, Richard; Rand, Emma; O'Toole, Peter J; Signoret, Nathalie

2018-05-22

Cell-to-cell communication engages signaling and spatiotemporal reorganization events driven by highly context-dependent and dynamic intercellular interactions, which are difficult to capture within heterogeneous primary cell cultures. Here, we present a straightforward correlative imaging approach utilizing commonly available instrumentation to sample large numbers of cell-cell interaction events, allowing qualitative and quantitative characterization of rare functioning cell-conjugates based on calcium signals. We applied this approach to examine a previously uncharacterized immunological synapse, investigating autologous human blood CD4 + T cells and monocyte-derived macrophages (MDMs) forming functional conjugates in vitro. Populations of signaling conjugates were visualized, tracked and analyzed by combining live imaging, calcium recording and multivariate statistical analysis. Correlative immunofluorescence was added to quantify endogenous molecular recruitments at the cell-cell junction. By analyzing a large number of rare conjugates, we were able to define calcium signatures associated with different states of CD4 + T cell-MDM interactions. Quantitative image analysis of immunostained conjugates detected the propensity of endogenous T cell surface markers and intracellular organelles to polarize towards cell-cell junctions with high and sustained calcium signaling profiles, hence defining immunological synapses. Overall, we developed a broadly applicable approach enabling detailed single cell- and population-based investigations of rare cell-cell communication events with primary cells.

Early Development of Functional Network Segregation Revealed by Connectomic Analysis of the Preterm Human Brain.

PubMed

Cao, Miao; He, Yong; Dai, Zhengjia; Liao, Xuhong; Jeon, Tina; Ouyang, Minhui; Chalak, Lina; Bi, Yanchao; Rollins, Nancy; Dong, Qi; Huang, Hao

2017-03-01

Human brain functional networks are topologically organized with nontrivial connectivity characteristics such as small-worldness and densely linked hubs to support highly segregated and integrated information processing. However, how they emerge and change at very early developmental phases remains poorly understood. Here, we used resting-state functional MRI and voxel-based graph theory analysis to systematically investigate the topological organization of whole-brain networks in 40 infants aged around 31 to 42 postmenstrual weeks. The functional connectivity strength and heterogeneity increased significantly in primary motor, somatosensory, visual, and auditory regions, but much less in high-order default-mode and executive-control regions. The hub and rich-club structures in primary regions were already present at around 31 postmenstrual weeks and exhibited remarkable expansions with age, accompanied by increased local clustering and shortest path length, indicating a transition from a relatively random to a more organized configuration. Moreover, multivariate pattern analysis using support vector regression revealed that individual brain maturity of preterm babies could be predicted by the network connectivity patterns. Collectively, we highlighted a gradually enhanced functional network segregation manner in the third trimester, which is primarily driven by the rapid increases of functional connectivity of the primary regions, providing crucial insights into the topological development patterns prior to birth. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Global Image Dissimilarity in Macaque Inferotemporal Cortex Predicts Human Visual Search Efficiency

PubMed Central

Sripati, Arun P.; Olson, Carl R.

2010-01-01

Finding a target in a visual scene can be easy or difficult depending on the nature of the distractors. Research in humans has suggested that search is more difficult the more similar the target and distractors are to each other. However, it has not yielded an objective definition of similarity. We hypothesized that visual search performance depends on similarity as determined by the degree to which two images elicit overlapping patterns of neuronal activity in visual cortex. To test this idea, we recorded from neurons in monkey inferotemporal cortex (IT) and assessed visual search performance in humans using pairs of images formed from the same local features in different global arrangements. The ability of IT neurons to discriminate between two images was strongly predictive of the ability of humans to discriminate between them during visual search, accounting overall for 90% of the variance in human performance. A simple physical measure of global similarity – the degree of overlap between the coarse footprints of a pair of images – largely explains both the neuronal and the behavioral results. To explain the relation between population activity and search behavior, we propose a model in which the efficiency of global oddball search depends on contrast-enhancing lateral interactions in high-order visual cortex. PMID:20107054

Human Factors Engineering Program Review Model

DTIC Science & Technology

2004-02-01

Institute, 1993). ANSI HFS-100: American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (American National... American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (ANSI HFS-100-1988). Santa Monica, California

A Mouse Model of Visual Perceptual Learning Reveals Alterations in Neuronal Coding and Dendritic Spine Density in the Visual Cortex.

PubMed

Wang, Yan; Wu, Wei; Zhang, Xian; Hu, Xu; Li, Yue; Lou, Shihao; Ma, Xiao; An, Xu; Liu, Hui; Peng, Jing; Ma, Danyi; Zhou, Yifeng; Yang, Yupeng

2016-01-01

Visual perceptual learning (VPL) can improve spatial vision in normally sighted and visually impaired individuals. Although previous studies of humans and large animals have explored the neural basis of VPL, elucidation of the underlying cellular and molecular mechanisms remains a challenge. Owing to the advantages of molecular genetic and optogenetic manipulations, the mouse is a promising model for providing a mechanistic understanding of VPL. Here, we thoroughly evaluated the effects and properties of VPL on spatial vision in C57BL/6J mice using a two-alternative, forced-choice visual water task. Briefly, the mice underwent prolonged training at near the individual threshold of contrast or spatial frequency (SF) for pattern discrimination or visual detection for 35 consecutive days. Following training, the contrast-threshold trained mice showed an 87% improvement in contrast sensitivity (CS) and a 55% gain in visual acuity (VA). Similarly, the SF-threshold trained mice exhibited comparable and long-lasting improvements in VA and significant gains in CS over a wide range of SFs. Furthermore, learning largely transferred across eyes and stimulus orientations. Interestingly, learning could transfer from a pattern discrimination task to a visual detection task, but not vice versa. We validated that this VPL fully restored VA in adult amblyopic mice and old mice. Taken together, these data indicate that mice, as a species, exhibit reliable VPL. Intrinsic signal optical imaging revealed that mice with perceptual training had higher cut-off SFs in primary visual cortex (V1) than those without perceptual training. Moreover, perceptual training induced an increase in the dendritic spine density in layer 2/3 pyramidal neurons of V1. These results indicated functional and structural alterations in V1 during VPL. Overall, our VPL mouse model will provide a platform for investigating the neurobiological basis of VPL.

Instrument Display Visual Angles for Conventional Aircraft and the MQ-9 Ground Control Station

NASA Technical Reports Server (NTRS)

Bendrick, Gregg A.; Kamine, Tovy Haber

2008-01-01

Aircraft instrument panels should be designed such that primary displays are in optimal viewing location to minimize pilot perception and response time. Human Factors engineers define three zones (i.e. "cones") of visual location: 1) "Easy Eye Movement" (foveal vision); 2) "Maximum Eye Movement" (peripheral vision with saccades), and 3) "Head Movement" (head movement required). Instrument display visual angles were measured to determine how well conventional aircraft (T-34, T-38, F- 15B, F-16XL, F/A-18A, U-2D, ER-2, King Air, G-III, B-52H, DC-10, B747-SCA) and the MQ-9 ground control station (GCS) complied with these standards, and how they compared with each other. Methods: Selected instrument parameters included: attitude, pitch, bank, power, airspeed, altitude, vertical speed, heading, turn rate, slip/skid, AOA, flight path, latitude, longitude, course, bearing, range and time. Vertical and horizontal visual angles for each component were measured from the pilot s eye position in each system. Results: The vertical visual angles of displays in conventional aircraft lay within the cone of "Easy Eye Movement" for all but three of the parameters measured, and almost all of the horizontal visual angles fell within this range. All conventional vertical and horizontal visual angles lay within the cone of "Maximum Eye Movement". However, most instrument vertical visual angles of the MQ-9 GCS lay outside the cone of "Easy Eye Movement", though all were within the cone of "Maximum Eye Movement". All the horizontal visual angles for the MQ-9 GCS were within the cone of "Easy Eye Movement". Discussion: Most instrument displays in conventional aircraft lay within the cone of "Easy Eye Movement", though mission-critical instruments sometimes displaced less important instruments outside this area. Many of the MQ-9 GCS systems lay outside this area. Specific training for MQ-9 pilots may be needed to avoid increased response time and potential error during flight.

The evolution of the complex sensory and motor systems of the human brain

PubMed Central

Kaas, Jon H.

2008-01-01

Inferences about how the complex sensory and motor systems of the human brain evolved are based on the results of comparative studies of brain organization across a range of mammalian species, and evidence from the endocasts of fossil skulls of key extinct species. The endocasts of the skulls of early mammals indicate that they had small brains with little neocortex. Evidence from comparative studies of cortical organization from small-brained mammals of the six major branches of mammalian evolution supports the conclusion that the small neocortex of early mammals was divided into roughly 20–25 cortical areas, including primary and secondary sensory fields. In early primates, vision was the dominant sense, and cortical areas associated with vision in temporal and occipital cortex underwent a significant expansion. Comparative studies indicate that early primates had 10 or more visual areas, and somatosensory areas with expanded representations of the forepaw. Posterior parietal cortex was also expanded, with a caudal half dominated by visual inputs, and a rostral half dominated by somatosensory inputs with outputs to an array of seven or more motor and visuomotor areas of the frontal lobe. Somatosensory areas and posterior parietal cortex became further differentiated in early anthropoid primates. As larger brains evolved in early apes and in our hominin ancestors, the number of cortical areas increased to reach an estimated 200 or so in present day humans, and hemispheric specializations emerged. The large human brain grew primarily by increasing neuron number rather than increasing average neuron size. PMID:18331903

Automated detection of diabetic retinopathy: barriers to translation into clinical practice.

PubMed

Abramoff, Michael D; Niemeijer, Meindert; Russell, Stephen R

2010-03-01

Automated identification of diabetic retinopathy (DR), the primary cause of blindness and visual loss for those aged 18-65 years, from color images of the retina has enormous potential to increase the quality, cost-effectiveness and accessibility of preventative care for people with diabetes. Through advanced image analysis techniques, retinal images are analyzed for abnormalities that define and correlate with the severity of DR. Translating automated DR detection into clinical practice will require surmounting scientific and nonscientific barriers. Scientific concerns, such as DR detection limits compared with human experts, can be studied and measured. Ethical, legal and political issues can be addressed, but are difficult or impossible to measure. The primary objective of this review is to survey the methods, potential benefits and limitations of automated detection in order to better manage translation into clinical practice, based on extensive experience with the systems we have developed.

Digital Images and Human Vision

NASA Technical Reports Server (NTRS)

Watson, Andrew B.; Null, Cynthia H. (Technical Monitor)

1997-01-01

Processing of digital images destined for visual consumption raises many interesting questions regarding human visual sensitivity. This talk will survey some of these questions, including some that have been answered and some that have not. There will be an emphasis upon visual masking, and a distinction will be drawn between masking due to contrast gain control processes, and due to processes such as hypothesis testing, pattern recognition, and visual search.

Advances in understanding the molecular basis of the first steps in color vision.

PubMed

Hofmann, Lukas; Palczewski, Krzysztof

2015-11-01

Serving as one of our primary environmental inputs, vision is the most sophisticated sensory system in humans. Here, we present recent findings derived from energetics, genetics and physiology that provide a more advanced understanding of color perception in mammals. Energetics of cis-trans isomerization of 11-cis-retinal accounts for color perception in the narrow region of the electromagnetic spectrum and how human eyes can absorb light in the near infrared (IR) range. Structural homology models of visual pigments reveal complex interactions of the protein moieties with the light sensitive chromophore 11-cis-retinal and that certain color blinding mutations impair secondary structural elements of these G protein-coupled receptors (GPCRs). Finally, we identify unsolved critical aspects of color tuning that require future investigation. Copyright © 2015. Published by Elsevier Ltd.

The Anatomical and Functional Organization of the Human Visual Pulvinar

PubMed Central

Pinsk, Mark A.; Kastner, Sabine

2015-01-01

The pulvinar is the largest nucleus in the primate thalamus and contains extensive, reciprocal connections with visual cortex. Although the anatomical and functional organization of the pulvinar has been extensively studied in old and new world monkeys, little is known about the organization of the human pulvinar. Using high-resolution functional magnetic resonance imaging at 3 T, we identified two visual field maps within the ventral pulvinar, referred to as vPul1 and vPul2. Both maps contain an inversion of contralateral visual space with the upper visual field represented ventrally and the lower visual field represented dorsally. vPul1 and vPul2 border each other at the vertical meridian and share a representation of foveal space with iso-eccentricity lines extending across areal borders. Additional, coarse representations of contralateral visual space were identified within ventral medial and dorsal lateral portions of the pulvinar. Connectivity analyses on functional and diffusion imaging data revealed a strong distinction in thalamocortical connectivity between the dorsal and ventral pulvinar. The two maps in the ventral pulvinar were most strongly connected with early and extrastriate visual areas. Given the shared eccentricity representation and similarity in cortical connectivity, we propose that these two maps form a distinct visual field map cluster and perform related functions. The dorsal pulvinar was most strongly connected with parietal and frontal areas. The functional and anatomical organization observed within the human pulvinar was similar to the organization of the pulvinar in other primate species. SIGNIFICANCE STATEMENT The anatomical organization and basic response properties of the visual pulvinar have been extensively studied in nonhuman primates. Yet, relatively little is known about the functional and anatomical organization of the human pulvinar. Using neuroimaging, we found multiple representations of visual space within the ventral human pulvinar and extensive topographically organized connectivity with visual cortex. This organization is similar to other nonhuman primates and provides additional support that the general organization of the pulvinar is consistent across the primate phylogenetic tree. These results suggest that the human pulvinar, like other primates, is well positioned to regulate corticocortical communication. PMID:26156987

The effects of acute alcohol exposure on the response properties of neurons in visual cortex area 17 of cats

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

Chen Bo; State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Science, Beijing 100101; Xia Jing

Physiological and behavioral studies have demonstrated that a number of visual functions such as visual acuity, contrast sensitivity, and motion perception can be impaired by acute alcohol exposure. The orientation- and direction-selective responses of cells in primary visual cortex are thought to participate in the perception of form and motion. To investigate how orientation selectivity and direction selectivity of neurons are influenced by acute alcohol exposure in vivo, we used the extracellular single-unit recording technique to examine the response properties of neurons in primary visual cortex (A17) of adult cats. We found that alcohol reduces spontaneous activity, visual evoked unitmore » responses, the signal-to-noise ratio, and orientation selectivity of A17 cells. In addition, small but detectable changes in both the preferred orientation/direction and the bandwidth of the orientation tuning curve of strongly orientation-biased A17 cells were observed after acute alcohol administration. Our findings may provide physiological evidence for some alcohol-related deficits in visual function observed in behavioral studies.« less

A comparative psychophysical approach to visual perception in primates.

PubMed

Matsuno, Toyomi; Fujita, Kazuo

2009-04-01

Studies on the visual processing of primates, which have well developed visual systems, provide essential information about the perceptual bases of their higher-order cognitive abilities. Although the mechanisms underlying visual processing are largely shared between human and nonhuman primates, differences have also been reported. In this article, we review psychophysical investigations comparing the basic visual processing that operates in human and nonhuman species, and discuss the future contributions potentially deriving from such comparative psychophysical approaches to primate minds.

Spinal Cord Injury Disrupts Resting-State Networks in the Human Brain.

PubMed

Hawasli, Ammar H; Rutlin, Jerrel; Roland, Jarod L; Murphy, Rory K J; Song, Sheng-Kwei; Leuthardt, Eric C; Shimony, Joshua S; Ray, Wilson Z

2018-03-15

Despite 253,000 spinal cord injury (SCI) patients in the United States, little is known about how SCI affects brain networks. Spinal MRI provides only structural information with no insight into functional connectivity. Resting-state functional MRI (RS-fMRI) quantifies network connectivity through the identification of resting-state networks (RSNs) and allows detection of functionally relevant changes during disease. Given the robust network of spinal cord afferents to the brain, we hypothesized that SCI produces meaningful changes in brain RSNs. RS-fMRIs and functional assessments were performed on 10 SCI subjects. Blood oxygen-dependent RS-fMRI sequences were acquired. Seed-based correlation mapping was performed using five RSNs: default-mode (DMN), dorsal-attention (DAN), salience (SAL), control (CON), and somatomotor (SMN). RSNs were compared with normal control subjects using false-discovery rate-corrected two way t tests. SCI reduced brain network connectivity within the SAL, SMN, and DMN and disrupted anti-correlated connectivity between CON and SMN. When divided into separate cohorts, complete but not incomplete SCI disrupted connectivity within SAL, DAN, SMN and DMN and between CON and SMN. Finally, connectivity changed over time after SCI: the primary motor cortex decreased connectivity with the primary somatosensory cortex, the visual cortex decreased connectivity with the primary motor cortex, and the visual cortex decreased connectivity with the sensory parietal cortex. These unique findings demonstrate the functional network plasticity that occurs in the brain as a result of injury to the spinal cord. Connectivity changes after SCI may serve as biomarkers to predict functional recovery following an SCI and guide future therapy.

The Effect of a Computerized Visual Perception and Visual-Motor Integration Training Program on Improving Chinese Handwriting of Children with Handwriting Difficulties

ERIC Educational Resources Information Center

Poon, K. W.; Li-Tsang, C. W .P.; Weiss, T. P. L.; Rosenblum, S.

2010-01-01

This study aimed to investigate the effect of a computerized visual perception and visual-motor integration training program to enhance Chinese handwriting performance among children with learning difficulties, particularly those with handwriting problems. Participants were 26 primary-one children who were assessed by educational psychologists and…

The Effect of Visual and Auditory Enhancements on Excitability of the Primary Motor Cortex during Motor Imagery: A Pilot Study

ERIC Educational Resources Information Center

Ikeda, Kohei; Higashi, Toshio; Sugawara, Kenichi; Tomori, Kounosuke; Kinoshita, Hiroshi; Kasai, Tatsuya

2012-01-01

The effect of visual and auditory enhancements of finger movement on corticospinal excitability during motor imagery (MI) was investigated using the transcranial magnetic stimulation technique. Motor-evoked potentials were elicited from the abductor digit minimi muscle during MI with auditory, visual and, auditory and visual information, and no…

Investigation of the Relationship between the Spatial Visualization Success and Visual/Spatial Intelligence Capabilities of Sixth Grade Students

ERIC Educational Resources Information Center

Yenilmez, Kursat; Kakmaci, Ozlem

2015-01-01

The main aim of this research was to examine the relationship between the spatial visualization success and visual/spatial intelligence capabilities of sixth grade students. The sample of the research consists of 1011 sixth grade students who were randomly selected from the primary schools in Eskisehir. In this correlational study, data were…

Paintings, photographs, and computer graphics are calculated appearances

NASA Astrophysics Data System (ADS)

McCann, John

2012-03-01

Painters reproduce the appearances they see, or visualize. The entire human visual system is the first part of that process, providing extensive spatial processing. Painters have used spatial techniques since the Renaissance to render HDR scenes. Silver halide photography responds to the light falling on single film pixels. Film can only mimic the retinal response of the cones at the start of the visual process. Film cannot mimic the spatial processing in humans. Digital image processing can. This talk studies three dramatic visual illusions and uses the spatial mechanisms found in human vision to interpret their appearances.

Changes of Visual Pathway and Brain Connectivity in Glaucoma: A Systematic Review

PubMed Central

Nuzzi, Raffaele; Dallorto, Laura; Rolle, Teresa

2018-01-01

Background: Glaucoma is a leading cause of irreversible blindness worldwide. The increasing interest in the involvement of the cortical visual pathway in glaucomatous patients is due to the implications in recent therapies, such as neuroprotection and neuroregeneration. Objective: In this review, we outline the current understanding of brain structural, functional, and metabolic changes detected with the modern techniques of neuroimaging in glaucomatous subjects. Methods: We screened MEDLINE, EMBASE, CINAHL, CENTRAL, LILACS, Trip Database, and NICE for original contributions published until 31 October 2017. Studies with at least six patients affected by any type of glaucoma were considered. We included studies using the following neuroimaging techniques: functional Magnetic Resonance Imaging (fMRI), resting-state fMRI (rs-fMRI), magnetic resonance spectroscopy (MRS), voxel- based Morphometry (VBM), surface-based Morphometry (SBM), diffusion tensor MRI (DTI). Results: Over a total of 1,901 studies, 56 case series with a total of 2,381 patients were included. Evidence of neurodegenerative process in glaucomatous patients was found both within and beyond the visual system. Structural alterations in visual cortex (mainly reduced cortex thickness and volume) have been demonstrated with SBM and VBM; these changes were not limited to primary visual cortex but also involved association visual areas. Other brain regions, associated with visual function, demonstrated a certain grade of increased or decreased gray matter volume. Functional and metabolic abnormalities resulted within primary visual cortex in all studies with fMRI and MRS. Studies with rs-fMRI found disrupted connectivity between the primary and higher visual cortex and between visual cortex and associative visual areas in the task-free state of glaucomatous patients. Conclusions: This review contributes to the better understanding of brain abnormalities in glaucoma. It may stimulate further speculation about brain plasticity at a later age and therapeutic strategies, such as the prevention of cortical degeneration in patients with glaucoma. Structural, functional, and metabolic neuroimaging methods provided evidence of changes throughout the visual pathway in glaucomatous patients. Other brain areas, not directly involved in the processing of visual information, also showed alterations. PMID:29896087

Spatial Visualization--A Gateway to Computer-Based Technology.

ERIC Educational Resources Information Center

Norman, Kent L.

1994-01-01

A model is proposed for the influence of individual differences on performance when computer-based technology is introduced. The primary cognitive factor driving differences in performance is spatial visualization ability. Four techniques for mitigating the negative impact of low spatial visualization are discussed: spatial metaphors, graphical…

Modification of visual function by early visual experience.

PubMed

Blakemore, C

1976-07-01

Physiological experiments, involving recording from the visual cortex in young kittens and monkeys, have given new insight into human developmental disorders. In the visual cortex of normal cats and monkeys most neurones are selectively sensitive to the orientation of moving edges and they receive very similar signals from both eyes. Even in very young kittens without visual experience, most neurones are binocularly driven and a small proportion of them are genuinely orientation selective. There is no passive maturation of the system in the absence of visual experience, but even very brief exposure to patterned images produces rapid emergence of the adult organization. These results are compared to observations on humans who have "recovered" from early blindness. Covering one eye in a kitten or a monkey, during a sensitive period early in life, produces a virtually complete loss of input from that eye in the cortex. These results can be correlated with the production of "stimulus deprivation amblyopia" in infants who have had one eye patched. Induction of a strabismus causes a loss of binocularity in the visual cortex, and in humans it leads to a loss of stereoscopic vision and binocular fusion. Exposing kittens to lines of one orientation modifies the preferred orientations of cortical cells and there is an analogous "meridional amblyopia" in astigmatic humans. The existence of a sensitive period in human vision is discussed, as well as the possibility of designing remedial and preventive treatments for human developmental disorders.

Interrelations in the Development of Primary School Learners' Creative Imagination and Creative Activity When Depicting a Portrait in Visual Art Lessons

ERIC Educational Resources Information Center

Šlahova, Aleksandra; Volonte, Ilze; Cacka, Maris

2017-01-01

Creative imagination is a psychic process of creating a new original image, idea or art work based on the acquired knowledge, skills, and abilities as well as on the experience of creative activity. The best of all primary school learners' creative imagination develops at the lessons of visual art, aimed at teaching them to understand what is…

[The key parameters of design research and analysis of the Chinese reading visual acuity chart].

PubMed

Wang, Chen-xiao; Liu, Zhi-hui; Gao, Ji-tuo; Guo, Ying-xuan; He, Ji-cang; Qu, Jia; Lü, Fan

2013-06-01

Reading is a visual function human being used to understand environmental events based on writing materials. This study investigated the feasibility of reading visual acuity chart in assessment of reading ability by analysis of the key factors involved in the design of the visual acuity chart. The reading level was determined as grade 3 primary school with Song as the font and 30 characters included in the sentences. Each of the sentences consisted of 27 commonly-used Chinese characters (9 characters between any two punctuations) and 3 punctuations. There were no contextual clues between the 80 sentences selected. The characters had 13 different sizes with an increment of 0.1 log unit (e.g.1.2589) and 2.5 pt was determined as the critical threshold. Readable test for visual target was followed as (1) 29 candidates with a raw or corrected visual acuity (VA)of at least 1.0 were selected to read 80 selected sentences with the size of characters of 2.5 pt at a distance of 40 cm, (2) the time used for reading with the number of characters wrongly read was recorded, (3) 39 sentences were selected as visual targets based on reading speed, effective reading position and total number of character strokes, (4) The 39 selected sentences were then randomly divided into 3 groups with no significant difference among the groups in the 3 factors listed at (3) with paired t-test. This reading visual chart was at level of Grade 3 primary school with a total stroke number of 165-210(Mean 185 ± 10), 13 font sizes a 0.1 log unit increment, a song pattern and 2.5 pt as the critical threshold. All candidates achieved 100% correct in reading test under 2.5 pt with an effective reading speed as 120.65-162 wpm (Mean 142.93 ± 11.80) and effective reading position as 36.03-61.48(Mean 48.85 ± 6.81). The reading test for the 3 groups of sentences showed effective reading speed as (142.49 ± 12.14) wpm,(142.86 ± 12.55) wpm and (143.44 ± 11.63) wpm respectively(t1-2 = -0.899, t2-3 = -1.295, t1-3 = -1.435). The reading position was 48.55 ± 6.69, 48.99 ± 7.49 and 49.00 ± 6.76, respectively(t1-2 = -1.019, t2-3 = -0.019, t1-3 = -0.816). The total number of character strokes was 185.54 ± 7.55, 187.69 ± 13.76 and 182.62 ± 8.17, respectively(t1-2 = 0.191, t2-3 = 1.385, t1-3 = 1.686). A practical design of the Chinese reading visual chart should consider size, increment, legibility in selection of reading sentences. Reading visual acuity, critical threshold and effective reading speed could be used to express the reading visual function.

Using Saliency-Weighted Disparity Statistics for Objective Visual Comfort Assessment of Stereoscopic Images

NASA Astrophysics Data System (ADS)

Zhang, Wenlan; Luo, Ting; Jiang, Gangyi; Jiang, Qiuping; Ying, Hongwei; Lu, Jing

2016-06-01

Visual comfort assessment (VCA) for stereoscopic images is a particularly significant yet challenging task in 3D quality of experience research field. Although the subjective assessment given by human observers is known as the most reliable way to evaluate the experienced visual discomfort, it is time-consuming and non-systematic. Therefore, it is of great importance to develop objective VCA approaches that can faithfully predict the degree of visual discomfort as human beings do. In this paper, a novel two-stage objective VCA framework is proposed. The main contribution of this study is that the important visual attention mechanism of human visual system is incorporated for visual comfort-aware feature extraction. Specifically, in the first stage, we first construct an adaptive 3D visual saliency detection model to derive saliency map of a stereoscopic image, and then a set of saliency-weighted disparity statistics are computed and combined to form a single feature vector to represent a stereoscopic image in terms of visual comfort. In the second stage, a high dimensional feature vector is fused into a single visual comfort score by performing random forest algorithm. Experimental results on two benchmark databases confirm the superior performance of the proposed approach.

Human Factors in Streaming Data Analysis: Challenges and Opportunities for Information Visualization

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

Dasgupta, Aritra; Arendt, Dustin L.; Franklin, Lyndsey

State-of-the-art visual analytics models and frameworks mostly assume a static snapshot of the data, while in many cases it is a stream with constant updates and changes. Exploration of streaming data poses unique challenges as machine-level computations and abstractions need to be synchronized with the visual representation of the data and the temporally evolving human insights. In the visual analytics literature, we lack a thorough characterization of streaming data and analysis of the challenges associated with task abstraction, visualization design, and adaptation of the role of human-in-the-loop for exploration of data streams. We aim to fill this gap by conductingmore » a survey of the state-of-the-art in visual analytics of streaming data for systematically describing the contributions and shortcomings of current techniques and analyzing the research gaps that need to be addressed in the future. Our contributions are: i) problem characterization for identifying challenges that are unique to streaming data analysis tasks, ii) a survey and analysis of the state-of-the-art in streaming data visualization research with a focus on the visualization design space for dynamic data and the role of the human-in-the-loop, and iii) reflections on the design-trade-offs for streaming visual analytics techniques and their practical applicability in real-world application scenarios.« less

Localization of MEG human brain responses to retinotopic visual stimuli with contrasting source reconstruction approaches

PubMed Central

Cicmil, Nela; Bridge, Holly; Parker, Andrew J.; Woolrich, Mark W.; Krug, Kristine

2014-01-01

Magnetoencephalography (MEG) allows the physiological recording of human brain activity at high temporal resolution. However, spatial localization of the source of the MEG signal is an ill-posed problem as the signal alone cannot constrain a unique solution and additional prior assumptions must be enforced. An adequate source reconstruction method for investigating the human visual system should place the sources of early visual activity in known locations in the occipital cortex. We localized sources of retinotopic MEG signals from the human brain with contrasting reconstruction approaches (minimum norm, multiple sparse priors, and beamformer) and compared these to the visual retinotopic map obtained with fMRI in the same individuals. When reconstructing brain responses to visual stimuli that differed by angular position, we found reliable localization to the appropriate retinotopic visual field quadrant by a minimum norm approach and by beamforming. Retinotopic map eccentricity in accordance with the fMRI map could not consistently be localized using an annular stimulus with any reconstruction method, but confining eccentricity stimuli to one visual field quadrant resulted in significant improvement with the minimum norm. These results inform the application of source analysis approaches for future MEG studies of the visual system, and indicate some current limits on localization accuracy of MEG signals. PMID:24904268

Gamma-oscillations modulated by picture naming and word reading: Intracranial recording in epileptic patients

PubMed Central

Wu, Helen C.; Nagasawa, Tetsuro; Brown, Erik C.; Juhasz, Csaba; Rothermel, Robert; Hoechstetter, Karsten; Shah, Aashit; Mittal, Sandeep; Fuerst, Darren; Sood, Sandeep; Asano, Eishi

2011-01-01

Objective We measured cortical gamma-oscillations in response to visual-language tasks consisting of picture naming and word reading in an effort to better understand human visual-language pathways. Methods We studied six patients with focal epilepsy who underwent extraoperative electrocorticography (ECoG) recording. Patients were asked to overtly name images presented sequentially in the picture naming task and to overtly read written words in the reading task. Results Both tasks commonly elicited gamma-augmentation (maximally at 80–100 Hz) on ECoG in the occipital, inferior-occipital-temporal and inferior-Rolandic areas, bilaterally. Picture naming, compared to reading task, elicited greater gamma-augmentation in portions of pre-motor areas as well as occipital and inferior-occipital-temporal areas, bilaterally. In contrast, word reading elicited greater gamma-augmentation in portions of bilateral occipital, left occipital-temporal and left superior-posterior-parietal areas. Gamma-attenuation was elicited by both tasks in portions of posterior cingulate and ventral premotor-prefrontal areas bilaterally. The number of letters in a presented word was positively correlated to the degree of gamma-augmentation in the medial occipital areas. Conclusions Gamma-augmentation measured on ECoG identified cortical areas commonly and differentially involved in picture naming and reading tasks. Longer words may activate the primary visual cortex for the more peripheral field. Significance The present study increases our understanding of the visual-language pathways. PMID:21498109

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

Unravelling Boléro: progressive aphasia, transmodal creativity and the right posterior neocortex.

PubMed

Seeley, William W; Matthews, Brandy R; Crawford, Richard K; Gorno-Tempini, Maria Luisa; Foti, Dean; Mackenzie, Ian R; Miller, Bruce L

2008-01-01

Most neurological lesion studies emphasize performance deficits that result from focal brain injury. Here, we describe striking gains of function in a patient with primary progressive aphasia, a degenerative disease of the human language network. During the decade before her language deficits arose, Anne Adams (AA), a lifelong scientist, developed an intense drive to produce visual art. Paintings from AA's artistic peak revealed her capacity to create expressive transmodal art, such as renderings of music in paint, which may have reflected an increased subjective relatedness among internal perceptual and conceptual images. AA became fascinated with Maurice Ravel, the French composer who also suffered from a progressive aphasia, and painted his best-known work, 'Boléro', by translating its musical elements into visual form. Later paintings, achieved when AA was nearly mute, moved towards increasing photographic realism, perhaps because visual representations came to dominate AA's mental landscape during this phase of her illness. Neuroimaging analyses revealed that, despite severe degeneration of left inferior frontal-insular, temporal and striatal regions, AA showed increased grey matter volume and hyperperfusion in right posterior neocortical areas implicated in heteromodal and polysensory integration. The findings suggest that structural and functional enhancements in non-dominant posterior neocortex may give rise to specific forms of visual creativity that can be liberated by dominant inferior frontal cortex injury.

Eye movement-invariant representations in the human visual system.

PubMed

Nishimoto, Shinji; Huth, Alexander G; Bilenko, Natalia Y; Gallant, Jack L

2017-01-01

During natural vision, humans make frequent eye movements but perceive a stable visual world. It is therefore likely that the human visual system contains representations of the visual world that are invariant to eye movements. Here we present an experiment designed to identify visual areas that might contain eye-movement-invariant representations. We used functional MRI to record brain activity from four human subjects who watched natural movies. In one condition subjects were required to fixate steadily, and in the other they were allowed to freely make voluntary eye movements. The movies used in each condition were identical. We reasoned that the brain activity recorded in a visual area that is invariant to eye movement should be similar under fixation and free viewing conditions. In contrast, activity in a visual area that is sensitive to eye movement should differ between fixation and free viewing. We therefore measured the similarity of brain activity across repeated presentations of the same movie within the fixation condition, and separately between the fixation and free viewing conditions. The ratio of these measures was used to determine which brain areas are most likely to contain eye movement-invariant representations. We found that voxels located in early visual areas are strongly affected by eye movements, while voxels in ventral temporal areas are only weakly affected by eye movements. These results suggest that the ventral temporal visual areas contain a stable representation of the visual world that is invariant to eye movements made during natural vision.

Transcriptional architecture of the primate neocortex.

PubMed

Bernard, Amy; Lubbers, Laura S; Tanis, Keith Q; Luo, Rui; Podtelezhnikov, Alexei A; Finney, Eva M; McWhorter, Mollie M E; Serikawa, Kyle; Lemon, Tracy; Morgan, Rebecca; Copeland, Catherine; Smith, Kimberly; Cullen, Vivian; Davis-Turak, Jeremy; Lee, Chang-Kyu; Sunkin, Susan M; Loboda, Andrey P; Levine, David M; Stone, David J; Hawrylycz, Michael J; Roberts, Christopher J; Jones, Allan R; Geschwind, Daniel H; Lein, Ed S

2012-03-22

Genome-wide transcriptional profiling was used to characterize the molecular underpinnings of neocortical organization in rhesus macaque, including cortical areal specialization and laminar cell-type diversity. Microarray analysis of individual cortical layers across sensorimotor and association cortices identified robust and specific molecular signatures for individual cortical layers and areas, prominently involving genes associated with specialized neuronal function. Overall, transcriptome-based relationships were related to spatial proximity, being strongest between neighboring cortical areas and between proximal layers. Primary visual cortex (V1) displayed the most distinctive gene expression compared to other cortical regions in rhesus and human, both in the specialized layer 4 as well as other layers. Laminar patterns were more similar between macaque and human compared to mouse, as was the unique V1 profile that was not observed in mouse. These data provide a unique resource detailing neocortical transcription patterns in a nonhuman primate with great similarity in gene expression to human. Copyright © 2012 Elsevier Inc. All rights reserved.

Toxoplasma Modulates Signature Pathways of Human Epilepsy, Neurodegeneration & Cancer.

PubMed

Ngô, Huân M; Zhou, Ying; Lorenzi, Hernan; Wang, Kai; Kim, Taek-Kyun; Zhou, Yong; El Bissati, Kamal; Mui, Ernest; Fraczek, Laura; Rajagopala, Seesandra V; Roberts, Craig W; Henriquez, Fiona L; Montpetit, Alexandre; Blackwell, Jenefer M; Jamieson, Sarra E; Wheeler, Kelsey; Begeman, Ian J; Naranjo-Galvis, Carlos; Alliey-Rodriguez, Ney; Davis, Roderick G; Soroceanu, Liliana; Cobbs, Charles; Steindler, Dennis A; Boyer, Kenneth; Noble, A Gwendolyn; Swisher, Charles N; Heydemann, Peter T; Rabiah, Peter; Withers, Shawn; Soteropoulos, Patricia; Hood, Leroy; McLeod, Rima

2017-09-13

One third of humans are infected lifelong with the brain-dwelling, protozoan parasite, Toxoplasma gondii. Approximately fifteen million of these have congenital toxoplasmosis. Although neurobehavioral disease is associated with seropositivity, causality is unproven. To better understand what this parasite does to human brains, we performed a comprehensive systems analysis of the infected brain: We identified susceptibility genes for congenital toxoplasmosis in our cohort of infected humans and found these genes are expressed in human brain. Transcriptomic and quantitative proteomic analyses of infected human, primary, neuronal stem and monocytic cells revealed effects on neurodevelopment and plasticity in neural, immune, and endocrine networks. These findings were supported by identification of protein and miRNA biomarkers in sera of ill children reflecting brain damage and T. gondii infection. These data were deconvoluted using three systems biology approaches: "Orbital-deconvolution" elucidated upstream, regulatory pathways interconnecting human susceptibility genes, biomarkers, proteomes, and transcriptomes. "Cluster-deconvolution" revealed visual protein-protein interaction clusters involved in processes affecting brain functions and circuitry, including lipid metabolism, leukocyte migration and olfaction. Finally, "disease-deconvolution" identified associations between the parasite-brain interactions and epilepsy, movement disorders, Alzheimer's disease, and cancer. This "reconstruction-deconvolution" logic provides templates of progenitor cells' potentiating effects, and components affecting human brain parasitism and diseases.

Three-Dimension Visualization for Primary Wheat Diseases Based on Simulation Model

NASA Astrophysics Data System (ADS)

Shijuan, Li; Yeping, Zhu

Crop simulation model has been becoming the core of agricultural production management and resource optimization management. Displaying crop growth process makes user observe the crop growth and development intuitionisticly. On the basis of understanding and grasping the occurrence condition, popularity season, key impact factors for main wheat diseases of stripe rust, leaf rust, stem rust, head blight and powdery mildew from research material and literature, we designed 3D visualization model for wheat growth and diseases occurrence. The model system will help farmer, technician and decision-maker to use crop growth simulation model better and provide decision-making support. Now 3D visualization model for wheat growth on the basis of simulation model has been developed, and the visualization model for primary wheat diseases is in the process of development.

Crossmodal Connections of Primary Sensory Cortices Largely Vanish During Normal Aging

PubMed Central

Henschke, Julia U.; Ohl, Frank W.; Budinger, Eike

2018-01-01

During aging, human response times (RTs) to unisensory and crossmodal stimuli decrease. However, the elderly benefit more from crossmodal stimulus representations than younger people. The underlying short-latency multisensory integration process is mediated by direct crossmodal connections at the level of primary sensory cortices. We investigate the age-related changes of these connections using a rodent model (Mongolian gerbil), retrograde tracer injections into the primary auditory (A1), somatosensory (S1), and visual cortex (V1), and immunohistochemistry for markers of apoptosis (Caspase-3), axonal plasticity (Growth associated protein 43, GAP 43), and a calcium-binding protein (Parvalbumin, PV). In adult animals, primary sensory cortices receive a substantial number of direct thalamic inputs from nuclei of their matched, but also from nuclei of non-matched sensory modalities. There are also direct intracortical connections among primary sensory cortices and connections with secondary sensory cortices of other modalities. In very old animals, the crossmodal connections strongly decrease in number or vanish entirely. This is likely due to a retraction of the projection neuron axonal branches rather than ongoing programmed cell death. The loss of crossmodal connections is also accompanied by changes in anatomical correlates of inhibition and excitation in the sensory thalamus and cortex. Together, the loss and restructuring of crossmodal connections during aging suggest a shift of multisensory processing from primary cortices towards other sensory brain areas in elderly individuals. PMID:29551970

Crossmodal Connections of Primary Sensory Cortices Largely Vanish During Normal Aging.

PubMed

Henschke, Julia U; Ohl, Frank W; Budinger, Eike

2018-01-01

During aging, human response times (RTs) to unisensory and crossmodal stimuli decrease. However, the elderly benefit more from crossmodal stimulus representations than younger people. The underlying short-latency multisensory integration process is mediated by direct crossmodal connections at the level of primary sensory cortices. We investigate the age-related changes of these connections using a rodent model (Mongolian gerbil), retrograde tracer injections into the primary auditory (A1), somatosensory (S1), and visual cortex (V1), and immunohistochemistry for markers of apoptosis (Caspase-3), axonal plasticity (Growth associated protein 43, GAP 43), and a calcium-binding protein (Parvalbumin, PV). In adult animals, primary sensory cortices receive a substantial number of direct thalamic inputs from nuclei of their matched, but also from nuclei of non-matched sensory modalities. There are also direct intracortical connections among primary sensory cortices and connections with secondary sensory cortices of other modalities. In very old animals, the crossmodal connections strongly decrease in number or vanish entirely. This is likely due to a retraction of the projection neuron axonal branches rather than ongoing programmed cell death. The loss of crossmodal connections is also accompanied by changes in anatomical correlates of inhibition and excitation in the sensory thalamus and cortex. Together, the loss and restructuring of crossmodal connections during aging suggest a shift of multisensory processing from primary cortices towards other sensory brain areas in elderly individuals.

Program Supports Scientific Visualization

NASA Technical Reports Server (NTRS)

Keith, Stephan

1994-01-01

Primary purpose of General Visualization System (GVS) computer program is to support scientific visualization of data generated by panel-method computer program PMARC_12 (inventory number ARC-13362) on Silicon Graphics Iris workstation. Enables user to view PMARC geometries and wakes as wire frames or as light shaded objects. GVS is written in C language.

Through Green Eyes: Complex Visual Culture and Post-Literacy

ERIC Educational Resources Information Center

Dobrin, Sidney I.

2010-01-01

By way of reclamation of the metaphor "green," this paper contends that research regarding the relationships between children's literatures and cultures and environmental experience requires a reinvigorated consideration of the role of the visual. The heightened importance of visual texts is made evident via three primary, contemporary conditions…

Analyzing the Reading Skills and Visual Perception Levels of First Grade Students

ERIC Educational Resources Information Center

Çayir, Aybala

2017-01-01

The purpose of this study was to analyze primary school first grade students' reading levels and correlate their visual perception skills. For this purpose, students' reading speed, reading comprehension and reading errors were determined using The Informal Reading Inventory. Students' visual perception levels were also analyzed using…

Artificial neural network models: A decision support tool for enhancing seedling selection in sugarcane

USDA-ARS?s Scientific Manuscript database

Currently, sugarcane selection begins at the seedling stage with visual selection for cane yield and other yield-related traits. Although subjective and inefficient, visual selection remains the primary method for selection. Visual selection is inefficient because of the confounding effect of genoty...

Action perception in individuals with congenital blindness or deafness: how does the loss of a sensory modality from birth affect perception-induced motor facilitation?

PubMed

Alaerts, Kaat; Swinnen, Stephan P; Wenderoth, Nicole

2011-05-01

Seeing or hearing manual actions activates the mirror neuron system, that is, specialized neurons within motor areas which fire when an action is performed but also when it is passively perceived. Using TMS, it was shown that motor cortex of typically developed subjects becomes facilitated not only from seeing others' actions, but also from merely hearing action-related sounds. In the present study, TMS was used for the first time to explore the "auditory" and "visual" responsiveness of motor cortex in individuals with congenital blindness or deafness. TMS was applied over left primary motor cortex (M1) to measure cortico-motor facilitation while subjects passively perceived manual actions (either visually or aurally). Although largely unexpected, congenitally blind or deaf subjects displayed substantially lower resonant motor facilitation upon action perception compared to seeing/hearing control subjects. Moreover, muscle-specific changes in cortico-motor excitability within M1 appeared to be absent in individuals with profound blindness or deafness. Overall, these findings strongly argue against the hypothesis that an increased reliance on the remaining sensory modality in blind or deaf subjects is accompanied by an increased responsiveness of the "auditory" or "visual" perceptual-motor "mirror" system, respectively. Moreover, the apparent lack of resonant motor facilitation for the blind and deaf subjects may challenge the hypothesis of a unitary mirror system underlying human action recognition and may suggest that action perception in blind and deaf subjects engages a mode of action processing that is different from the human action recognition system recruited in typically developed subjects.

Data Visualization Saliency Model: A Tool for Evaluating Abstract Data Visualizations

DOE PAGES

Matzen, Laura E.; Haass, Michael J.; Divis, Kristin M.; ...

2017-08-29

Evaluating the effectiveness of data visualizations is a challenging undertaking and often relies on one-off studies that test a visualization in the context of one specific task. Researchers across the fields of data science, visualization, and human-computer interaction are calling for foundational tools and principles that could be applied to assessing the effectiveness of data visualizations in a more rapid and generalizable manner. One possibility for such a tool is a model of visual saliency for data visualizations. Visual saliency models are typically based on the properties of the human visual cortex and predict which areas of a scene havemore » visual features (e.g. color, luminance, edges) that are likely to draw a viewer's attention. While these models can accurately predict where viewers will look in a natural scene, they typically do not perform well for abstract data visualizations. In this paper, we discuss the reasons for the poor performance of existing saliency models when applied to data visualizations. We introduce the Data Visualization Saliency (DVS) model, a saliency model tailored to address some of these weaknesses, and we test the performance of the DVS model and existing saliency models by comparing the saliency maps produced by the models to eye tracking data obtained from human viewers. In conclusion, we describe how modified saliency models could be used as general tools for assessing the effectiveness of visualizations, including the strengths and weaknesses of this approach.« less

Data Visualization Saliency Model: A Tool for Evaluating Abstract Data Visualizations

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

Matzen, Laura E.; Haass, Michael J.; Divis, Kristin M.

Evaluating the effectiveness of data visualizations is a challenging undertaking and often relies on one-off studies that test a visualization in the context of one specific task. Researchers across the fields of data science, visualization, and human-computer interaction are calling for foundational tools and principles that could be applied to assessing the effectiveness of data visualizations in a more rapid and generalizable manner. One possibility for such a tool is a model of visual saliency for data visualizations. Visual saliency models are typically based on the properties of the human visual cortex and predict which areas of a scene havemore » visual features (e.g. color, luminance, edges) that are likely to draw a viewer's attention. While these models can accurately predict where viewers will look in a natural scene, they typically do not perform well for abstract data visualizations. In this paper, we discuss the reasons for the poor performance of existing saliency models when applied to data visualizations. We introduce the Data Visualization Saliency (DVS) model, a saliency model tailored to address some of these weaknesses, and we test the performance of the DVS model and existing saliency models by comparing the saliency maps produced by the models to eye tracking data obtained from human viewers. In conclusion, we describe how modified saliency models could be used as general tools for assessing the effectiveness of visualizations, including the strengths and weaknesses of this approach.« less

A Simple Network Architecture Accounts for Diverse Reward Time Responses in Primary Visual Cortex.

PubMed

Huertas, Marco A; Hussain Shuler, Marshall G; Shouval, Harel Z

2015-09-16

Many actions performed by animals and humans depend on an ability to learn, estimate, and produce temporal intervals of behavioral relevance. Exemplifying such learning of cued expectancies is the observation of reward-timing activity in the primary visual cortex (V1) of rodents, wherein neural responses to visual cues come to predict the time of future reward as behaviorally experienced in the past. These reward-timing responses exhibit significant heterogeneity in at least three qualitatively distinct classes: sustained increase or sustained decrease in firing rate until the time of expected reward, and a class of cells that reach a peak in firing at the expected delay. We elaborate upon our existing model by including inhibitory and excitatory units while imposing simple connectivity rules to demonstrate what role these inhibitory elements and the simple architectures play in sculpting the response dynamics of the network. We find that simply adding inhibition is not sufficient for obtaining the different distinct response classes, and that a broad distribution of inhibitory projections is necessary for obtaining peak-type responses. Furthermore, although changes in connection strength that modulate the effects of inhibition onto excitatory units have a strong impact on the firing rate profile of these peaked responses, the network exhibits robustness in its overall ability to predict the expected time of reward. Finally, we demonstrate how the magnitude of expected reward can be encoded at the expected delay in the network and how peaked responses express this reward expectancy. Heterogeneity in single-neuron responses is a common feature of neuronal systems, although sometimes, in theoretical approaches, it is treated as a nuisance and seldom considered as conveying a different aspect of a signal. In this study, we focus on the heterogeneous responses in the primary visual cortex of rodents trained with a predictable delayed reward time. We describe under what conditions this heterogeneity can arise by self-organization, and what information it can convey. This study, while focusing on a specific system, provides insight onto how heterogeneity can arise in general while also shedding light onto mechanisms of reinforcement learning using realistic biological assumptions. Copyright © 2015 the authors 0270-6474/15/3512659-14$15.00/0.

Dissociated emergent-response system and fine-processing system in human neural network and a heuristic neural architecture for autonomous humanoid robots.

PubMed

Yan, Xiaodan

2010-01-01

The current study investigated the functional connectivity of the primary sensory system with resting state fMRI and applied such knowledge into the design of the neural architecture of autonomous humanoid robots. Correlation and Granger causality analyses were utilized to reveal the functional connectivity patterns. Dissociation was within the primary sensory system, in that the olfactory cortex and the somatosensory cortex were strongly connected to the amygdala whereas the visual cortex and the auditory cortex were strongly connected with the frontal cortex. The posterior cingulate cortex (PCC) and the anterior cingulate cortex (ACC) were found to maintain constant communication with the primary sensory system, the frontal cortex, and the amygdala. Such neural architecture inspired the design of dissociated emergent-response system and fine-processing system in autonomous humanoid robots, with separate processing units and another consolidation center to coordinate the two systems. Such design can help autonomous robots to detect and respond quickly to danger, so as to maintain their sustainability and independence.

Multitasking During Degraded Speech Recognition in School-Age Children

PubMed Central

Ward, Kristina M.; Brehm, Laurel

2017-01-01

Multitasking requires individuals to allocate their cognitive resources across different tasks. The purpose of the current study was to assess school-age children’s multitasking abilities during degraded speech recognition. Children (8 to 12 years old) completed a dual-task paradigm including a sentence recognition (primary) task containing speech that was either unprocessed or noise-band vocoded with 8, 6, or 4 spectral channels and a visual monitoring (secondary) task. Children’s accuracy and reaction time on the visual monitoring task was quantified during the dual-task paradigm in each condition of the primary task and compared with single-task performance. Children experienced dual-task costs in the 6- and 4-channel conditions of the primary speech recognition task with decreased accuracy on the visual monitoring task relative to baseline performance. In all conditions, children’s dual-task performance on the visual monitoring task was strongly predicted by their single-task (baseline) performance on the task. Results suggest that children’s proficiency with the secondary task contributes to the magnitude of dual-task costs while multitasking during degraded speech recognition. PMID:28105890

Multitasking During Degraded Speech Recognition in School-Age Children.

PubMed

Grieco-Calub, Tina M; Ward, Kristina M; Brehm, Laurel

2017-01-01

Multitasking requires individuals to allocate their cognitive resources across different tasks. The purpose of the current study was to assess school-age children's multitasking abilities during degraded speech recognition. Children (8 to 12 years old) completed a dual-task paradigm including a sentence recognition (primary) task containing speech that was either unprocessed or noise-band vocoded with 8, 6, or 4 spectral channels and a visual monitoring (secondary) task. Children's accuracy and reaction time on the visual monitoring task was quantified during the dual-task paradigm in each condition of the primary task and compared with single-task performance. Children experienced dual-task costs in the 6- and 4-channel conditions of the primary speech recognition task with decreased accuracy on the visual monitoring task relative to baseline performance. In all conditions, children's dual-task performance on the visual monitoring task was strongly predicted by their single-task (baseline) performance on the task. Results suggest that children's proficiency with the secondary task contributes to the magnitude of dual-task costs while multitasking during degraded speech recognition.

Visualization and quantitative analysis of extrachromosomal telomere-repeat DNA in individual human cells by Halo-FISH

PubMed Central

Komosa, Martin; Root, Heather; Meyn, M. Stephen

2015-01-01

Current methods for characterizing extrachromosomal nuclear DNA in mammalian cells do not permit single-cell analysis, are often semi-quantitative and frequently biased toward the detection of circular species. To overcome these limitations, we developed Halo-FISH to visualize and quantitatively analyze extrachromosomal DNA in single cells. We demonstrate Halo-FISH by using it to analyze extrachromosomal telomere-repeat (ECTR) in human cells that use the Alternative Lengthening of Telomeres (ALT) pathway(s) to maintain telomere lengths. We find that GM847 and VA13 ALT cells average ∼80 detectable G/C-strand ECTR DNA molecules/nucleus, while U2OS ALT cells average ∼18 molecules/nucleus. In comparison, human primary and telomerase-positive cells contain <5 ECTR DNA molecules/nucleus. ECTR DNA in ALT cells exhibit striking cell-to-cell variations in number (<20 to >300), range widely in length (<1 to >200 kb) and are composed of primarily G- or C-strand telomere-repeat DNA. Halo-FISH enables, for the first time, the simultaneous analysis of ECTR DNA and chromosomal telomeres in a single cell. We find that ECTR DNA comprises ∼15% of telomere-repeat DNA in GM847 and VA13 cells, but <4% in U2OS cells. In addition to its use in ALT cell analysis, Halo-FISH can facilitate the study of a wide variety of extrachromosomal DNA in mammalian cells. PMID:25662602

The Effects of Phacoemulsification and Intraocular Lens Implantation on Anatomical and Functional Parameters in Patients with Primary Angle Closure: A Prospective Study. (An American Ophthalmological Society Thesis).

PubMed

Traverso, Carlo Enrico; Cutolo, Carlo Alberto

2017-08-01

To investigate the clinical, anatomical, and patient-reported outcomes of phacoemulsification (PE) with intraocular lens implantation performed to treat primary angle closure (PAC) and primary angle-closure glaucoma (PACG). Patients were evaluated at baseline and at 6 months after PE. The examination included visual acuity, intraocular pressure (IOP), visual field, optic nerve head, endothelial cell count (ECC), aqueous depth, and ocular biometric parameters. Patient-reported visual function and health status were assessed. Coprimary outcome measures were IOP changes, angle widening, and patient-reported visual function; secondary outcome measures were visual acuity changes, use of IOP-lowering medications, and complications. Univariate and multivariate analyses were performed to determine the predictors of IOP change. Thirty-nine cases were identified, and postoperative data were analyzed for 59 eyes, 39 with PACG and 20 with PAC. Globally, PE resulted in a mean reduction in IOP of -6.33 mm Hg (95% CI, -8.64 to -4.01, P <.001). Aqueous depth and angle measurements improved ( P <.01), whereas ECC significantly decreased ( P <.001). Both corrected and uncorrected visual acuity improved ( P <.01). The EQ visual analog scale did not change ( P =.16), but VFQ-25 improved ( P <.01). The IOP-lowering effect of PE was greater in the PACG compared to the PAC group ( P =.04). In both groups, preoperative IOP was the most significant predictor of IOP change ( P <.01). No sight-threatening complications were recorded. Our data support the usefulness of PE in lowering the IOP in patients with PAC and PACG. Although PE resulted in several anatomical and patient-reported visual improvements, we observe that a marked decrease in ECC should be carefully weighed before surgery.

Featural and temporal attention selectively enhance task-appropriate representations in human V1

PubMed Central

Warren, Scott; Yacoub, Essa; Ghose, Geoffrey

2015-01-01

Our perceptions are often shaped by focusing our attention toward specific features or periods of time irrespective of location. We explore the physiological bases of these non-spatial forms of attention by imaging brain activity while subjects perform a challenging change detection task. The task employs a continuously varying visual stimulus that, for any moment in time, selectively activates functionally distinct subpopulations of primary visual cortex (V1) neurons. When subjects are cued to the timing and nature of the change, the mapping of orientation preference across V1 was systematically shifts toward the cued stimulus just prior to its appearance. A simple linear model can explain this shift: attentional changes are selectively targeted toward neural subpopulations representing the attended feature at the times the feature was anticipated. Our results suggest that featural attention is mediated by a linear change in the responses of task-appropriate neurons across cortex during appropriate periods of time. PMID:25501983

Phosphodiesterase Inhibition Increases CREB Phosphorylation and Restores Orientation Selectivity in a Model of Fetal Alcohol Spectrum Disorders

PubMed Central

Krahe, Thomas E.; Wang, Weili; Medina, Alexandre E.

2009-01-01

Background Fetal alcohol spectrum disorders (FASD) are the leading cause of mental retardation in the western world and children with FASD present altered somatosensory, auditory and visual processing. There is growing evidence that some of these sensory processing problems may be related to altered cortical maps caused by impaired developmental neuronal plasticity. Methodology/Principal Findings Here we show that the primary visual cortex of ferrets exposed to alcohol during the third trimester equivalent of human gestation have decreased CREB phosphorylation and poor orientation selectivity revealed by western blotting, optical imaging of intrinsic signals and single-unit extracellular recording techniques. Treating animals several days after the period of alcohol exposure with a phosphodiesterase type 1 inhibitor (Vinpocetine) increased CREB phosphorylation and restored orientation selectivity columns and neuronal orientation tuning. Conclusions/Significance These findings suggest that CREB function is important for the maturation of orientation selectivity and that plasticity enhancement by vinpocetine may play a role in the treatment of sensory problems in FASD. PMID:19680548

Visual scanning behavior and pilot workload

NASA Technical Reports Server (NTRS)

Tole, J. R.; Stephens, A. T.; Vivaudou, M.; Ephrath, A. R.; Young, L. R.

1983-01-01

Sophisticated man machine interaction often requires the human operator to perform a stereotyped scan of various instruments in order to monitor and/or control a system. For situations in which this type of stereotyped behavior exists, such as certain phases of instrument flight, scan pattern was shown to be altered by the imposition of simultaneous verbal tasks. A study designed to examine the relationship between pilot visual scan of instruments and mental workload is described. It was found that a verbal loading task of varying difficulty causes pilots to stare at the primary instrument as the difficulty increases and to shed looks at instruments of less importance. The verbal loading task also affected the rank ordering of scanning sequences. By examining the behavior of pilots with widely varying skill levels, it was suggested that these effects occur most strongly at lower skill levels and are less apparent at high skill levels. A graphical interpretation of the hypothetical relationship between skill, workload, and performance is introduced and modelling results are presented to support this interpretation.

Visual and auditory cue integration for the generation of saccadic eye movements in monkeys and lever pressing in humans.

PubMed

Schiller, Peter H; Kwak, Michelle C; Slocum, Warren M

2012-08-01

This study examined how effectively visual and auditory cues can be integrated in the brain for the generation of motor responses. The latencies with which saccadic eye movements are produced in humans and monkeys form, under certain conditions, a bimodal distribution, the first mode of which has been termed express saccades. In humans, a much higher percentage of express saccades is generated when both visual and auditory cues are provided compared with the single presentation of these cues [H. C. Hughes et al. (1994) J. Exp. Psychol. Hum. Percept. Perform., 20, 131-153]. In this study, we addressed two questions: first, do monkeys also integrate visual and auditory cues for express saccade generation as do humans and second, does such integration take place in humans when, instead of eye movements, the task is to press levers with fingers? Our results show that (i) in monkeys, as in humans, the combined visual and auditory cues generate a much higher percentage of express saccades than do singly presented cues and (ii) the latencies with which levers are pressed by humans are shorter when both visual and auditory cues are provided compared with the presentation of single cues, but the distribution in all cases is unimodal; response latencies in the express range seen in the execution of saccadic eye movements are not obtained with lever pressing. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Objects Classification by Learning-Based Visual Saliency Model and Convolutional Neural Network.

PubMed

Li, Na; Zhao, Xinbo; Yang, Yongjia; Zou, Xiaochun

2016-01-01

Humans can easily classify different kinds of objects whereas it is quite difficult for computers. As a hot and difficult problem, objects classification has been receiving extensive interests with broad prospects. Inspired by neuroscience, deep learning concept is proposed. Convolutional neural network (CNN) as one of the methods of deep learning can be used to solve classification problem. But most of deep learning methods, including CNN, all ignore the human visual information processing mechanism when a person is classifying objects. Therefore, in this paper, inspiring the completed processing that humans classify different kinds of objects, we bring forth a new classification method which combines visual attention model and CNN. Firstly, we use the visual attention model to simulate the processing of human visual selection mechanism. Secondly, we use CNN to simulate the processing of how humans select features and extract the local features of those selected areas. Finally, not only does our classification method depend on those local features, but also it adds the human semantic features to classify objects. Our classification method has apparently advantages in biology. Experimental results demonstrated that our method made the efficiency of classification improve significantly.

Directly visualized glioblastoma-derived extracellular vesicles transfer RNA to microglia/macrophages in the brain

PubMed Central

van der Vos, Kristan E.; Abels, Erik R.; Zhang, Xuan; Lai, Charles; Carrizosa, Esteban; Oakley, Derek; Prabhakar, Shilpa; Mardini, Osama; Crommentuijn, Matheus H. W.; Skog, Johan; Krichevsky, Anna M.; Stemmer-Rachamimov, Anat; Mempel, Thorsten R.; El Khoury, Joseph; Hickman, Suzanne E.; Breakefield, Xandra O.

2016-01-01

Background To understand the ability of gliomas to manipulate their microenvironment, we visualized the transfer of vesicles and the effects of tumor-released extracellular RNA on the phenotype of microglia in culture and in vivo. Methods Extracellular vesicles (EVs) released from primary human glioblastoma (GBM) cells were isolated and microRNAs (miRNAs) were analyzed. Primary mouse microglia were exposed to GBM-EVs, and their uptake and effect on proliferation and levels of specific miRNAs, mRNAs, and proteins were analyzed. For in vivo analysis, mouse glioma cells were implanted in the brains of mice, and EV release and uptake by microglia and monocytes/macrophages were monitored by intravital 2-photon microscopy, immunohistochemistry, and fluorescence activated cell sorting analysis, as well as RNA and protein levels. Results Microglia avidly took up GBM-EVs, leading to increased proliferation and shifting of their cytokine profile toward immune suppression. High levels of miR-451/miR-21 in GBM-EVs were transferred to microglia with a decrease in the miR-451/miR-21 target c-Myc mRNA. In in vivo analysis, we directly visualized release of EVs from glioma cells and their uptake by microglia and monocytes/macrophages in brain. Dissociated microglia and monocytes/macrophages from tumor-bearing brains revealed increased levels of miR-21 and reduced levels of c-Myc mRNA. Conclusions Intravital microscopy confirms the release of EVs from gliomas and their uptake into microglia and monocytes/macrophages within the brain. Our studies also support functional effects of GBM-released EVs following uptake into microglia, associated in part with increased miRNA levels, decreased target mRNAs, and encoded proteins, presumably as a means for the tumor to manipulate its environs. PMID:26433199

Adaptive Optics Analysis of Visual Benefit with Higher-order Aberrations Correction of Human Eye - Poster Paper

NASA Astrophysics Data System (ADS)

Xue, Lixia; Dai, Yun; Rao, Xuejun; Wang, Cheng; Hu, Yiyun; Liu, Qian; Jiang, Wenhan

2008-01-01

Higher-order aberrations correction can improve visual performance of human eye to some extent. To evaluate how much visual benefit can be obtained with higher-order aberrations correction we developed an adaptive optics vision simulator (AOVS). Dynamic real time optimized modal compensation was used to implement various customized higher-order ocular aberrations correction strategies. The experimental results indicate that higher-order aberrations correction can improve visual performance of human eye comparing with only lower-order aberration correction but the improvement degree and higher-order aberration correction strategy are different from each individual. Some subjects can acquire great visual benefit when higher-order aberrations were corrected but some subjects acquire little visual benefit even though all higher-order aberrations were corrected. Therefore, relative to general lower-order aberrations correction strategy, customized higher-order aberrations correction strategy is needed to obtain optimal visual improvement for each individual. AOVS provides an effective tool for higher-order ocular aberrations optometry for customized ocular aberrations correction.

Development of Flexible Visual Recognition Memory in Human Infants

ERIC Educational Resources Information Center

Robinson, Astri J.; Pascalis, Olivier

2004-01-01

Research using the visual paired comparison task has shown that visual recognition memory across changing contexts is dependent on the integrity of the hippocampal formation in human adults and in monkeys. The acquisition of contextual flexibility may contribute to the change in memory performance that occurs late in the first year of life. To…

Bayesian learning of visual chunks by human observers

PubMed Central

Orbán, Gergő; Fiser, József; Aslin, Richard N.; Lengyel, Máté

2008-01-01

Efficient and versatile processing of any hierarchically structured information requires a learning mechanism that combines lower-level features into higher-level chunks. We investigated this chunking mechanism in humans with a visual pattern-learning paradigm. We developed an ideal learner based on Bayesian model comparison that extracts and stores only those chunks of information that are minimally sufficient to encode a set of visual scenes. Our ideal Bayesian chunk learner not only reproduced the results of a large set of previous empirical findings in the domain of human pattern learning but also made a key prediction that we confirmed experimentally. In accordance with Bayesian learning but contrary to associative learning, human performance was well above chance when pair-wise statistics in the exemplars contained no relevant information. Thus, humans extract chunks from complex visual patterns by generating accurate yet economical representations and not by encoding the full correlational structure of the input. PMID:18268353

Mechanisms of migraine aura revealed by functional MRI in human visual cortex

PubMed Central

Hadjikhani, Nouchine; Sanchez del Rio, Margarita; Wu, Ona; Schwartz, Denis; Bakker, Dick; Fischl, Bruce; Kwong, Kenneth K.; Cutrer, F. Michael; Rosen, Bruce R.; Tootell, Roger B. H.; Sorensen, A. Gregory; Moskowitz, Michael A.

2001-01-01

Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. However, it has been challenging to test this hypothesis in human cerebral cortex. Using high-field functional MRI with near-continuous recording during visual aura in three subjects, we observed blood oxygenation level-dependent (BOLD) signal changes that demonstrated at least eight characteristics of CSD, time-locked to percept/onset of the aura. Initially, a focal increase in BOLD signal (possibly reflecting vasodilation), developed within extrastriate cortex (area V3A). This BOLD change progressed contiguously and slowly (3.5 ± 1.1 mm/min) over occipital cortex, congruent with the retinotopy of the visual percept. Following the same retinotopic progression, the BOLD signal then diminished (possibly reflecting vasoconstriction after the initial vasodilation), as did the BOLD response to visual activation. During periods with no visual stimulation, but while the subject was experiencing scintillations, BOLD signal followed the retinotopic progression of the visual percept. These data strongly suggest that an electrophysiological event such as CSD generates the aura in human visual cortex. PMID:11287655

Regional Neural Response Differences in the Determination of Faces or Houses Positioned in a Wide Visual Field

PubMed Central

Wu, Jinglong; Chen, Kewei; Imajyo, Satoshi; Ohno, Seiichiro; Kanazawa, Susumu

2013-01-01

In human visual cortex, the primary visual cortex (V1) is considered to be essential for visual information processing; the fusiform face area (FFA) and parahippocampal place area (PPA) are considered as face-selective region and places-selective region, respectively. Recently, a functional magnetic resonance imaging (fMRI) study showed that the neural activity ratios between V1 and FFA were constant as eccentricities increasing in central visual field. However, in wide visual field, the neural activity relationships between V1 and FFA or V1 and PPA are still unclear. In this work, using fMRI and wide-view present system, we tried to address this issue by measuring neural activities in V1, FFA and PPA for the images of faces and houses aligning in 4 eccentricities and 4 meridians. Then, we further calculated ratio relative to V1 (RRV1) as comparing the neural responses amplitudes in FFA or PPA with those in V1. We found V1, FFA, and PPA showed significant different neural activities to faces and houses in 3 dimensions of eccentricity, meridian, and region. Most importantly, the RRV1s in FFA and PPA also exhibited significant differences in 3 dimensions. In the dimension of eccentricity, both FFA and PPA showed smaller RRV1s at central position than those at peripheral positions. In meridian dimension, both FFA and PPA showed larger RRV1s at upper vertical positions than those at lower vertical positions. In the dimension of region, FFA had larger RRV1s than PPA. We proposed that these differential RRV1s indicated FFA and PPA might have different processing strategies for encoding the wide field visual information from V1. These different processing strategies might depend on the retinal position at which faces or houses are typically observed in daily life. We posited a role of experience in shaping the information processing strategies in the ventral visual cortex. PMID:23991147

The effect of human engagement depicted in contextual photographs on the visual attention patterns of adults with traumatic brain injury.

PubMed

Thiessen, Amber; Brown, Jessica; Beukelman, David; Hux, Karen

2017-09-01

Photographs are a frequently employed tool for the rehabilitation of adults with traumatic brain injury (TBI). Speech-language pathologists (SLPs) working with these individuals must select photos that are easily identifiable and meaningful to their clients. In this investigation, we examined the visual attention response to camera- (i.e., depicted human figure looking toward camera) and task-engaged (i.e., depicted human figure looking at and touching an object) contextual photographs for a group of adults with TBI and a group of adults without neurological conditions. Eye-tracking technology served to accurately and objectively measure visual fixations. Although differences were hypothesized given the cognitive deficits associated with TBI, study results revealed little difference in the visual fixation patterns of adults with and without TBI. Specifically, both groups of participants tended to fixate rapidly on the depicted human figure and fixate more on objects in which a human figure was task-engaged than when a human figure was camera-engaged. These results indicate that strategic placement of human figures in a contextual photograph may modify the way in which individuals with TBI visually attend to and interpret photographs. In addition, task-engagement appears to have a guiding effect on visual attention that may be of benefit to SLPs hoping to select more effective contextual photographs for their clients with TBI. Finally, the limited differences in visual attention patterns between individuals with TBI and their age and gender matched peers without neurological impairments indicates that these two groups find similar photograph regions to be worthy of visual fixation. Readers will gain knowledge regarding the photograph selection process for individuals with TBI. In addition, readers will be able to identify camera- and task-engaged photographs and to explain why task-engagement may be a beneficial component of contextual photographs. Copyright © 2017 Elsevier Inc. All rights reserved.

An Application of Project-Based Learning in an Urban Project Topic in the Visual Arts Course in 8th Classes of Primary Education

ERIC Educational Resources Information Center

Kalyoncu, Raif; Tepecik, Adnan

2010-01-01

The purpose of this study is to measure the effect of project-based learning that is used in visual arts course on students' academic success and permanence. The research was applied to students of Hasan Ali Yucel Primary School in the city of Trabzon during the fall semester of 2007-2008 academic year. Among the sample that had been selected…

Visual salience metrics for image inpainting

NASA Astrophysics Data System (ADS)

Ardis, Paul A.; Singhal, Amit

2009-01-01

Quantitative metrics for successful image inpainting currently do not exist, with researchers instead relying upon qualitative human comparisons to evaluate their methodologies and techniques. In an attempt to rectify this situation, we propose two new metrics to capture the notions of noticeability and visual intent in order to evaluate inpainting results. The proposed metrics use a quantitative measure of visual salience based upon a computational model of human visual attention. We demonstrate how these two metrics repeatably correlate with qualitative opinion in a human observer study, correctly identify the optimum uses for exemplar-based inpainting (as specified in the original publication), and match qualitative opinion in published examples.

Pilot Task Profiles, Human Factors, And Image Realism

NASA Astrophysics Data System (ADS)

McCormick, Dennis

1982-06-01

Computer Image Generation (CIG) visual systems provide real time scenes for state-of-the-art flight training simulators. The visual system reauires a greater understanding of training tasks, human factors, and the concept of image realism to produce an effective and efficient training scene than is required by other types of visual systems. Image realism must be defined in terms of pilot visual information reauirements. Human factors analysis of training and perception is necessary to determine the pilot's information requirements. System analysis then determines how the CIG and display device can best provide essential information to the pilot. This analysis procedure ensures optimum training effectiveness and system performance.

Implied motion because of instability in Hokusai Manga activates the human motion-sensitive extrastriate visual cortex: an fMRI study of the impact of visual art.

PubMed

Osaka, Naoyuki; Matsuyoshi, Daisuke; Ikeda, Takashi; Osaka, Mariko

2010-03-10

The recent development of cognitive neuroscience has invited inference about the neurosensory events underlying the experience of visual arts involving implied motion. We report functional magnetic resonance imaging study demonstrating activation of the human extrastriate motion-sensitive cortex by static images showing implied motion because of instability. We used static line-drawing cartoons of humans by Hokusai Katsushika (called 'Hokusai Manga'), an outstanding Japanese cartoonist as well as famous Ukiyoe artist. We found 'Hokusai Manga' with implied motion by depicting human bodies that are engaged in challenging tonic posture significantly activated the motion-sensitive visual cortex including MT+ in the human extrastriate cortex, while an illustration that does not imply motion, for either humans or objects, did not activate these areas under the same tasks. We conclude that motion-sensitive extrastriate cortex would be a critical region for perception of implied motion in instability.

Evaluation of stereoscopic display with visual function and interview

NASA Astrophysics Data System (ADS)

Okuyama, Fumio

1999-05-01

The influence of binocular stereoscopic (3D) television display on the human eye were compared with one of a 2D display, using human visual function testing and interviews. A 40- inch double lenticular display was used for 2D/3D comparison experiments. Subjects observed the display for 30 minutes at a distance 1.0 m, with a combination of 2D material and one of 3D material. The participants were twelve young adults. Main optometric test with visual function measured were visual acuity, refraction, phoria, near vision point, accommodation etc. The interview consisted of 17 questions. Testing procedures were performed just before watching, just after watching, and forty-five minutes after watching. Changes in visual function are characterized as prolongation of near vision point, decrease of accommodation and increase in phoria. 3D viewing interview results show much more visual fatigue in comparison with 2D results. The conclusions are: 1) change in visual function is larger and visual fatigue is more intense when viewing 3D images. 2) The evaluation method with visual function and interview proved to be very satisfactory for analyzing the influence of stereoscopic display on human eye.

Qualitative similarities in the visual short-term memory of pigeons and people.

PubMed

Gibson, Brett; Wasserman, Edward; Luck, Steven J

2011-10-01

Visual short-term memory plays a key role in guiding behavior, and individual differences in visual short-term memory capacity are strongly predictive of higher cognitive abilities. To provide a broader evolutionary context for understanding this memory system, we directly compared the behavior of pigeons and humans on a change detection task. Although pigeons had a lower storage capacity and a higher lapse rate than humans, both species stored multiple items in short-term memory and conformed to the same basic performance model. Thus, despite their very different evolutionary histories and neural architectures, pigeons and humans have functionally similar visual short-term memory systems, suggesting that the functional properties of visual short-term memory are subject to similar selective pressures across these distant species.

Cognitive Consilience: Primate Non-Primary Neuroanatomical Circuits Underlying Cognition

PubMed Central

Solari, Soren Van Hout; Stoner, Rich

2011-01-01

Interactions between the cerebral cortex, thalamus, and basal ganglia form the basis of cognitive information processing in the mammalian brain. Understanding the principles of neuroanatomical organization in these structures is critical to understanding the functions they perform and ultimately how the human brain works. We have manually distilled and synthesized hundreds of primate neuroanatomy facts into a single interactive visualization. The resulting picture represents the fundamental neuroanatomical blueprint upon which cognitive functions must be implemented. Within this framework we hypothesize and detail 7 functional circuits corresponding to psychological perspectives on the brain: consolidated long-term declarative memory, short-term declarative memory, working memory/information processing, behavioral memory selection, behavioral memory output, cognitive control, and cortical information flow regulation. Each circuit is described in terms of distinguishable neuronal groups including the cerebral isocortex (9 pyramidal neuronal groups), parahippocampal gyrus and hippocampus, thalamus (4 neuronal groups), basal ganglia (7 neuronal groups), metencephalon, basal forebrain, and other subcortical nuclei. We focus on neuroanatomy related to primate non-primary cortical systems to elucidate the basis underlying the distinct homotypical cognitive architecture. To display the breadth of this review, we introduce a novel method of integrating and presenting data in multiple independent visualizations: an interactive website (http://www.frontiersin.org/files/cognitiveconsilience/index.html) and standalone iPhone and iPad applications. With these tools we present a unique, annotated view of neuroanatomical consilience (integration of knowledge). PMID:22194717

Cooperative processing in primary somatosensory cortex and posterior parietal cortex during tactile working memory.

PubMed

Ku, Yixuan; Zhao, Di; Bodner, Mark; Zhou, Yong-Di

2015-08-01

In the present study, causal roles of both the primary somatosensory cortex (SI) and the posterior parietal cortex (PPC) were investigated in a tactile unimodal working memory (WM) task. Individual magnetic resonance imaging-based single-pulse transcranial magnetic stimulation (spTMS) was applied, respectively, to the left SI (ipsilateral to tactile stimuli), right SI (contralateral to tactile stimuli) and right PPC (contralateral to tactile stimuli), while human participants were performing a tactile-tactile unimodal delayed matching-to-sample task. The time points of spTMS were 300, 600 and 900 ms after the onset of the tactile sample stimulus (duration: 200 ms). Compared with ipsilateral SI, application of spTMS over either contralateral SI or contralateral PPC at those time points significantly impaired the accuracy of task performance. Meanwhile, the deterioration in accuracy did not vary with the stimulating time points. Together, these results indicate that the tactile information is processed cooperatively by SI and PPC in the same hemisphere, starting from the early delay of the tactile unimodal WM task. This pattern of processing of tactile information is different from the pattern in tactile-visual cross-modal WM. In a tactile-visual cross-modal WM task, SI and PPC contribute to the processing sequentially, suggesting a process of sensory information transfer during the early delay between modalities. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Breaking Snake Camouflage: Humans Detect Snakes More Accurately than Other Animals under Less Discernible Visual Conditions.

PubMed

Kawai, Nobuyuki; He, Hongshen

2016-01-01

Humans and non-human primates are extremely sensitive to snakes as exemplified by their ability to detect pictures of snakes more quickly than those of other animals. These findings are consistent with the Snake Detection Theory, which hypothesizes that as predators, snakes were a major source of evolutionary selection that favored expansion of the visual system of primates for rapid snake detection. Many snakes use camouflage to conceal themselves from both prey and their own predators, making it very challenging to detect them. If snakes have acted as a selective pressure on primate visual systems, they should be more easily detected than other animals under difficult visual conditions. Here we tested whether humans discerned images of snakes more accurately than those of non-threatening animals (e.g., birds, cats, or fish) under conditions of less perceptual information by presenting a series of degraded images with the Random Image Structure Evolution technique (interpolation of random noise). We find that participants recognize mosaic images of snakes, which were regarded as functionally equivalent to camouflage, more accurately than those of other animals under dissolved conditions. The present study supports the Snake Detection Theory by showing that humans have a visual system that accurately recognizes snakes under less discernible visual conditions.

Breaking Snake Camouflage: Humans Detect Snakes More Accurately than Other Animals under Less Discernible Visual Conditions

PubMed Central

He, Hongshen

2016-01-01

Humans and non-human primates are extremely sensitive to snakes as exemplified by their ability to detect pictures of snakes more quickly than those of other animals. These findings are consistent with the Snake Detection Theory, which hypothesizes that as predators, snakes were a major source of evolutionary selection that favored expansion of the visual system of primates for rapid snake detection. Many snakes use camouflage to conceal themselves from both prey and their own predators, making it very challenging to detect them. If snakes have acted as a selective pressure on primate visual systems, they should be more easily detected than other animals under difficult visual conditions. Here we tested whether humans discerned images of snakes more accurately than those of non-threatening animals (e.g., birds, cats, or fish) under conditions of less perceptual information by presenting a series of degraded images with the Random Image Structure Evolution technique (interpolation of random noise). We find that participants recognize mosaic images of snakes, which were regarded as functionally equivalent to camouflage, more accurately than those of other animals under dissolved conditions. The present study supports the Snake Detection Theory by showing that humans have a visual system that accurately recognizes snakes under less discernible visual conditions. PMID:27783686

A Visual Analysis of the 1980 Houston Republican Presidential Primary Debate.

ERIC Educational Resources Information Center

Hellweg, Susan A.; Phillips, Steven L.

In partial replication of an analysis of the 1976 presidential campaign debates, two researchers analyzed the debate between Republican presidential candidates Ronald Reagan and George Bush (Houston, April 23, 1980) for its visual features, (amount and type of camera shots). The visual categories by which camera shots were coded included…

The Visual Differences of the Classroom Walls in Chilean Primary Schools

ERIC Educational Resources Information Center

Errázuriz, Luis; Portales, Carlos

2018-01-01

In a world increasingly saturated with images, the visual aesthetic dimension should play a more important role in the educational processes. Furthermore, classroom walls could be considered valuable resources to introduce visual literacy among children and teachers. However, Chilean educational policies tend not to pay much attention to visual…

Consistent Visual Analyses of Intrasubject Data

ERIC Educational Resources Information Center

Kahng, SungWoo; Chung, Kyong-Mee; Gutshall, Katharine; Pitts, Steven C.; Kao, Joyce; Girolami, Kelli

2010-01-01

Visual inspection of single-case data is the primary method of interpretation of the effects of an independent variable on a dependent variable in applied behavior analysis. The purpose of the current study was to replicate and extend the results of DeProspero and Cohen (1979) by reexamining the consistency of visual analysis across raters. We…

Correlation of pattern reversal visual evoked potential parameters with the pattern standard deviation in primary open angle glaucoma.

PubMed

Kothari, Ruchi; Bokariya, Pradeep; Singh, Ramji; Singh, Smita; Narang, Purvasha

2014-01-01

To evaluate whether glaucomatous visual field defect particularly the pattern standard deviation (PSD) of Humphrey visual field could be associated with visual evoked potential (VEP) parameters of patients having primary open angle glaucoma (POAG). Visual field by Humphrey perimetry and simultaneous recordings of pattern reversal visual evoked potential (PRVEP) were assessed in 100 patients with POAG. The stimulus configuration for VEP recordings consisted of the transient pattern reversal method in which a black and white checker board pattern was generated (full field) and displayed on VEP monitor (colour 14″) by an electronic pattern regenerator inbuilt in an evoked potential recorder (RMS EMG EP MARK II). The results of our study indicate that there is a highly significant (P<0.001) negative correlation of P100 amplitude and a statistically significant (P<0.05) positive correlation of N70 latency, P100 latency and N155 latency with the PSD of Humphrey visual field in the subjects of POAG in various age groups as evaluated by Student's t-test. Prolongation of VEP latencies were mirrored by a corresponding increase of PSD values. Conversely, as PSD increases the magnitude of VEP excursions were found to be diminished.

The stimulus-evoked population response in visual cortex of awake monkey is a propagating wave

PubMed Central

Muller, Lyle; Reynaud, Alexandre; Chavane, Frédéric; Destexhe, Alain

2014-01-01

Propagating waves occur in many excitable media and were recently found in neural systems from retina to neocortex. While propagating waves are clearly present under anaesthesia, whether they also appear during awake and conscious states remains unclear. One possibility is that these waves are systematically missed in trial-averaged data, due to variability. Here we present a method for detecting propagating waves in noisy multichannel recordings. Applying this method to single-trial voltage-sensitive dye imaging data, we show that the stimulus-evoked population response in primary visual cortex of the awake monkey propagates as a travelling wave, with consistent dynamics across trials. A network model suggests that this reliability is the hallmark of the horizontal fibre network of superficial cortical layers. Propagating waves with similar properties occur independently in secondary visual cortex, but maintain precise phase relations with the waves in primary visual cortex. These results show that, in response to a visual stimulus, propagating waves are systematically evoked in several visual areas, generating a consistent spatiotemporal frame for further neuronal interactions. PMID:24770473

Loss of Neurofilament Labeling in the Primary Visual Cortex of Monocularly Deprived Monkeys

PubMed Central

Duffy, Kevin R.; Livingstone, Margaret S.

2009-01-01

Visual experience during early life is important for the development of neural organizations that support visual function. Closing one eye (monocular deprivation) during this sensitive period can cause a reorganization of neural connections within the visual system that leaves the deprived eye functionally disconnected. We have assessed the pattern of neurofilament labeling in monocularly deprived macaque monkeys to examine the possibility that a cytoskeleton change contributes to deprivation-induced reorganization of neural connections within the primary visual cortex (V-1). Monocular deprivation for three months starting around the time of birth caused a significant loss of neurofilament labeling within deprived-eye ocular dominance columns. Three months of monocular deprivation initiated in adulthood did not produce a loss of neurofilament labeling. The evidence that neurofilament loss was found only when deprivation occurred during the sensitive period supports the notion that the loss permits restructuring of deprived-eye neural connections within the visual system. These results provide evidence that, in addition to reorganization of LGN inputs, the intrinsic circuitry of V-1 neurons is altered when monocular deprivation occurs early in development. PMID:15563721

Rural and urban Ugandan primary school children's alternative ideas about animals

NASA Astrophysics Data System (ADS)

Otaala, Justine

This study examined rural and urban Ugandan primary children's alternative ideas about animals through the use of qualitative research methods. Thirty-six children were selected from lower, middle, and upper primary grades in two primary schools (rural and urban). Data were collected using interview-about-instance technique. Children were shown 18 color photographs of instances and non-instances of familiar animals and asked to say if the photographed objects were animals or not. They were then asked to give reasons to justify their answers. The interviews were audiotaped and transcribed. The results indicate that children tended to apply the label "animal" to large mammals, usually found at home, on the farm, in the zoo, and in the wild. Humans were not categorized as animals, particularly by children in the lower grades. Although the children in upper grades correctly identified humans as animals, they used reasons that were irrelevant to animal attributes and improperly derived from the biological concept of evolution. Many attributes children used to categorize instances of animals were scientifically unacceptable and included superficial features, such as body outline, anatomical features (body parts), external features (visual cues), presence or absence and number of appendages. Movement and eating (nutrition) were the most popular attributes children used to identify instances of animals. The main differences in children's ideas emanated from the reasons used to identify animals. Older rural children drew upon their cultural and traditional practices more often than urban children. Anthropomorphic thinking was predominant among younger children in both settings, but diminished with progression in children's grade levels. Some of the implications of this study are: (1) teachers, teacher educators and curriculum developers should consider learners' ideas in planning and developing teaching materials and interventions. (2) Teachers should relate humans to other animals during instruction. (3) Textbooks and teaching materials need careful scrutiny to insure they include humans and other small animals as part of the animal kingdom. (4) Teaching interventions should begin with the basic attributes of animals and insure children understand the relationship between the attributes and concepts. (5) Encourage the use of examples and non-examples of the concept "animal" during instruction.

Investigation Of Integrating Three-Dimensional (3-D) Geometry Into The Visual Anatomical Injury Descriptor (Visual AID) Using WebGL

DTIC Science & Technology

2011-08-01

generated using the Zygote Human Anatomy 3-D model (3). Use of a reference anatomy independent of personal identification, such as Zygote, allows Visual...Zygote Human Anatomy 3D Model, 2010. http://www.zygote.com/ (accessed July 26, 2011). 4. Khronos Group Web site. Khronos to Create New Open Standard for...understanding of the information at hand. In order to fulfill the medical illustration track, I completed a concentration in science, focusing on human

Association of common genetic variants in GPCPD1 with scaling of visual cortical surface area in humans.

PubMed

Bakken, Trygve E; Roddey, J Cooper; Djurovic, Srdjan; Akshoomoff, Natacha; Amaral, David G; Bloss, Cinnamon S; Casey, B J; Chang, Linda; Ernst, Thomas M; Gruen, Jeffrey R; Jernigan, Terry L; Kaufmann, Walter E; Kenet, Tal; Kennedy, David N; Kuperman, Joshua M; Murray, Sarah S; Sowell, Elizabeth R; Rimol, Lars M; Mattingsdal, Morten; Melle, Ingrid; Agartz, Ingrid; Andreassen, Ole A; Schork, Nicholas J; Dale, Anders M; Weiner, Michael; Aisen, Paul; Petersen, Ronald; Jack, Clifford R; Jagust, William; Trojanowki, John Q; Toga, Arthur W; Beckett, Laurel; Green, Robert C; Saykin, Andrew J; Morris, John; Liu, Enchi; Montine, Tom; Gamst, Anthony; Thomas, Ronald G; Donohue, Michael; Walter, Sarah; Gessert, Devon; Sather, Tamie; Harvey, Danielle; Kornak, John; Dale, Anders; Bernstein, Matthew; Felmlee, Joel; Fox, Nick; Thompson, Paul; Schuff, Norbert; Alexander, Gene; DeCarli, Charles; Bandy, Dan; Koeppe, Robert A; Foster, Norm; Reiman, Eric M; Chen, Kewei; Mathis, Chet; Cairns, Nigel J; Taylor-Reinwald, Lisa; Trojanowki, J Q; Shaw, Les; Lee, Virginia M Y; Korecka, Magdalena; Crawford, Karen; Neu, Scott; Foroud, Tatiana M; Potkin, Steven; Shen, Li; Kachaturian, Zaven; Frank, Richard; Snyder, Peter J; Molchan, Susan; Kaye, Jeffrey; Quinn, Joseph; Lind, Betty; Dolen, Sara; Schneider, Lon S; Pawluczyk, Sonia; Spann, Bryan M; Brewer, James; Vanderswag, Helen; Heidebrink, Judith L; Lord, Joanne L; Johnson, Kris; Doody, Rachelle S; Villanueva-Meyer, Javier; Chowdhury, Munir; Stern, Yaakov; Honig, Lawrence S; Bell, Karen L; Morris, John C; Ances, Beau; Carroll, Maria; Leon, Sue; Mintun, Mark A; Schneider, Stacy; Marson, Daniel; Griffith, Randall; Clark, David; Grossman, Hillel; Mitsis, Effie; Romirowsky, Aliza; deToledo-Morrell, Leyla; Shah, Raj C; Duara, Ranjan; Varon, Daniel; Roberts, Peggy; Albert, Marilyn; Onyike, Chiadi; Kielb, Stephanie; Rusinek, Henry; de Leon, Mony J; Glodzik, Lidia; De Santi, Susan; Doraiswamy, P Murali; Petrella, Jeffrey R; Coleman, R Edward; Arnold, Steven E; Karlawish, Jason H; Wolk, David; Smith, Charles D; Jicha, Greg; Hardy, Peter; Lopez, Oscar L; Oakley, MaryAnn; Simpson, Donna M; Porsteinsson, Anton P; Goldstein, Bonnie S; Martin, Kim; Makino, Kelly M; Ismail, M Saleem; Brand, Connie; Mulnard, Ruth A; Thai, Gaby; Mc-Adams-Ortiz, Catherine; Womack, Kyle; Mathews, Dana; Quiceno, Mary; Diaz-Arrastia, Ramon; King, Richard; Weiner, Myron; Martin-Cook, Kristen; DeVous, Michael; Levey, Allan I; Lah, James J; Cellar, Janet S; Burns, Jeffrey M; Anderson, Heather S; Swerdlow, Russell H; Apostolova, Liana; Lu, Po H; Bartzokis, George; Silverman, Daniel H S; Graff-Radford, Neill R; Parfitt, Francine; Johnson, Heather; Farlow, Martin R; Hake, Ann Marie; Matthews, Brandy R; Herring, Scott; van Dyck, Christopher H; Carson, Richard E; MacAvoy, Martha G; Chertkow, Howard; Bergman, Howard; Hosein, Chris; Black, Sandra; Stefanovic, Bojana; Caldwell, Curtis; Ging-Yuek; Hsiung, Robin; Feldman, Howard; Mudge, Benita; Assaly, Michele; Kertesz, Andrew; Rogers, John; Trost, Dick; Bernick, Charles; Munic, Donna; Kerwin, Diana; Mesulam, Marek-Marsel; Lipowski, Kristina; Wu, Chuang-Kuo; Johnson, Nancy; Sadowsky, Carl; Martinez, Walter; Villena, Teresa; Turner, Raymond Scott; Johnson, Kathleen; Reynolds, Brigid; Sperling, Reisa A; Johnson, Keith A; Marshall, Gad; Frey, Meghan; Yesavage, Jerome; Taylor, Joy L; Lane, Barton; Rosen, Allyson; Tinklenberg, Jared; Sabbagh, Marwan; Belden, Christine; Jacobson, Sandra; Kowall, Neil; Killiany, Ronald; Budson, Andrew E; Norbash, Alexander; Johnson, Patricia Lynn; Obisesan, Thomas O; Wolday, Saba; Bwayo, Salome K; Lerner, Alan; Hudson, Leon; Ogrocki, Paula; Fletcher, Evan; Carmichael, Owen; Olichney, John; Kittur, Smita; Borrie, Michael; Lee, T-Y; Bartha, Rob; Johnson, Sterling; Asthana, Sanjay; Carlsson, Cynthia M; Potkin, Steven G; Preda, Adrian; Nguyen, Dana; Tariot, Pierre; Fleisher, Adam; Reeder, Stephanie; Bates, Vernice; Capote, Horacio; Rainka, Michelle; Scharre, Douglas W; Kataki, Maria; Zimmerman, Earl A; Celmins, Dzintra; Brown, Alice D; Pearlson, Godfrey D; Blank, Karen; Anderson, Karen; Santulli, Robert B; Schwartz, Eben S; Sink, Kaycee M; Williamson, Jeff D; Garg, Pradeep; Watkins, Franklin; Ott, Brian R; Querfurth, Henry; Tremont, Geoffrey; Salloway, Stephen; Malloy, Paul; Correia, Stephen; Rosen, Howard J; Miller, Bruce L; Mintzer, Jacobo; Longmire, Crystal Flynn; Spicer, Kenneth; Finger, Elizabether; Rachinsky, Irina; Drost, Dick; Jernigan, Terry; McCabe, Connor; Grant, Ellen; Ernst, Thomas; Kuperman, Josh; Chung, Yoon; Murray, Sarah; Bloss, Cinnamon; Darst, Burcu; Pritchett, Lexi; Saito, Ashley; Amaral, David; DiNino, Mishaela; Eyngorina, Bella; Sowell, Elizabeth; Houston, Suzanne; Soderberg, Lindsay; Kaufmann, Walter; van Zijl, Peter; Rizzo-Busack, Hilda; Javid, Mohsin; Mehta, Natasha; Ruberry, Erika; Powers, Alisa; Rosen, Bruce; Gebhard, Nitzah; Manigan, Holly; Frazier, Jean; Kennedy, David; Yakutis, Lauren; Hill, Michael; Gruen, Jeffrey; Bosson-Heenan, Joan; Carlson, Heatherly

2012-03-06

Visual cortical surface area varies two- to threefold between human individuals, is highly heritable, and has been correlated with visual acuity and visual perception. However, it is still largely unknown what specific genetic and environmental factors contribute to normal variation in the area of visual cortex. To identify SNPs associated with the proportional surface area of visual cortex, we performed a genome-wide association study followed by replication in two independent cohorts. We identified one SNP (rs6116869) that replicated in both cohorts and had genome-wide significant association (P(combined) = 3.2 × 10(-8)). Furthermore, a metaanalysis of imputed SNPs in this genomic region identified a more significantly associated SNP (rs238295; P = 6.5 × 10(-9)) that was in strong linkage disequilibrium with rs6116869. These SNPs are located within 4 kb of the 5' UTR of GPCPD1, glycerophosphocholine phosphodiesterase GDE1 homolog (Saccharomyces cerevisiae), which in humans, is more highly expressed in occipital cortex compared with the remainder of cortex than 99.9% of genes genome-wide. Based on these findings, we conclude that this common genetic variation contributes to the proportional area of human visual cortex. We suggest that identifying genes that contribute to normal cortical architecture provides a first step to understanding genetic mechanisms that underlie visual perception.

JavaScript: Data Visualizations

EPA Pesticide Factsheets

D3 is a JavaScript library that, in a manner similar to jQuery library, allows direct inspection and manipulation of the Document Object Model, but is intended for the primary purpose of data visualization.

MeRy-B, a metabolomic database and knowledge base for exploring plant primary metabolism.

PubMed

Deborde, Catherine; Jacob, Daniel

2014-01-01

Plant primary metabolites are organic compounds that are common to all or most plant species and are essential for plant growth, development, and reproduction. They are intermediates and products of metabolism involved in photosynthesis and other biosynthetic processes. Primary metabolites belong to different compound families, mainly carbohydrates, organic acids, amino acids, nucleotides, fatty acids, steroids, or lipids. Until recently, unlike the Human Metabolome Database ( http://www.hmdb.ca ) dedicated to human metabolism, there was no centralized database or repository dedicated exclusively to the plant kingdom that contained information on metabolites and their concentrations in a detailed experimental context. MeRy-B is the first platform for plant (1)H-NMR metabolomic profiles (MeRy-B, http://bit.ly/meryb ), designed to provide a knowledge base of curated plant profiles and metabolites obtained by NMR, together with the corresponding experimental and analytical metadata. MeRy-B contains lists of plant metabolites, mostly primary metabolites and unknown compounds, with information about experimental conditions, the factors studied, and metabolite concentrations for 19 different plant species (Arabidopsis, broccoli, daphne, grape, maize, barrel clover, melon, Ostreococcus tauri, palm date, palm tree, peach, pine tree, eucalyptus, plantain rice, strawberry, sugar beet, tomato, vanilla), compiled from more than 2,300 annotated NMR profiles for various organs or tissues deposited by 30 different private or public contributors in September 2013. Currently, about half of the data deposited in MeRy-B is publicly available. In this chapter, readers will be shown how to (1) navigate through and retrieve data of publicly available projects on MeRy-B website; (2) visualize lists of experimentally identified metabolites and their concentrations in all plant species present in MeRy-B; (3) get primary metabolite list for a particular plant species in MeRy-B; and for a particular tissue (4) find information on a primary metabolite regardless of the species.

Screening for Impaired Visual Acuity in Older Adults: US Preventive Services Task Force Recommendation Statement.

PubMed

Siu, Albert L; Bibbins-Domingo, Kirsten; Grossman, David C; Baumann, Linda Ciofu; Davidson, Karina W; Ebell, Mark; García, Francisco A R; Gillman, Matthew; Herzstein, Jessica; Kemper, Alex R; Krist, Alex H; Kurth, Ann E; Owens, Douglas K; Phillips, William R; Phipps, Maureen G; Pignone, Michael P

2016-03-01

Update of the US Preventive Services Task Force (USPSTF) recommendation on screening for impaired visual acuity in older adults. The USPSTF reviewed the evidence on screening for visual acuity impairment associated with uncorrected refractive error, cataracts, and age-related macular degeneration among adults 65 years or older in the primary care setting; the benefits and harms of screening; the accuracy of screening; and the benefits and harms of treatment of early vision impairment due to uncorrected refractive error, cataracts, and age-related macular degeneration. This recommendation applies to asymptomatic adults 65 years or older who do not present to their primary care clinician with vision problems. The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for impaired visual acuity in older adults. (I statement).

Gender-specific effects of prenatal and adolescent exposure to tobacco smoke on auditory and visual attention.

PubMed

Jacobsen, Leslie K; Slotkin, Theodore A; Mencl, W Einar; Frost, Stephen J; Pugh, Kenneth R

2007-12-01

Prenatal exposure to active maternal tobacco smoking elevates risk of cognitive and auditory processing deficits, and of smoking in offspring. Recent preclinical work has demonstrated a sex-specific pattern of reduction in cortical cholinergic markers following prenatal, adolescent, or combined prenatal and adolescent exposure to nicotine, the primary psychoactive component of tobacco smoke. Given the importance of cortical cholinergic neurotransmission to attentional function, we examined auditory and visual selective and divided attention in 181 male and female adolescent smokers and nonsmokers with and without prenatal exposure to maternal smoking. Groups did not differ in age, educational attainment, symptoms of inattention, or years of parent education. A subset of 63 subjects also underwent functional magnetic resonance imaging while performing an auditory and visual selective and divided attention task. Among females, exposure to tobacco smoke during prenatal or adolescent development was associated with reductions in auditory and visual attention performance accuracy that were greatest in female smokers with prenatal exposure (combined exposure). Among males, combined exposure was associated with marked deficits in auditory attention, suggesting greater vulnerability of neurocircuitry supporting auditory attention to insult stemming from developmental exposure to tobacco smoke in males. Activation of brain regions that support auditory attention was greater in adolescents with prenatal or adolescent exposure to tobacco smoke relative to adolescents with neither prenatal nor adolescent exposure to tobacco smoke. These findings extend earlier preclinical work and suggest that, in humans, prenatal and adolescent exposure to nicotine exerts gender-specific deleterious effects on auditory and visual attention, with concomitant alterations in the efficiency of neurocircuitry supporting auditory attention.

Drawing enhances cross-modal memory plasticity in the human brain: a case study in a totally blind adult

PubMed Central

Likova, Lora T.

2012-01-01

In a memory-guided drawing task under blindfolded conditions, we have recently used functional Magnetic Resonance Imaging (fMRI) to demonstrate that the primary visual cortex (V1) may operate as the visuo-spatial buffer, or “sketchpad,” for working memory. The results implied, however, a modality-independent or amodal form of its operation. In the present study, to validate the role of V1 in non-visual memory, we eliminated not only the visual input but all levels of visual processing by replicating the paradigm in a congenitally blind individual. Our novel Cognitive-Kinesthetic method was used to train this totally blind subject to draw complex images guided solely by tactile memory. Control tasks of tactile exploration and memorization of the image to be drawn, and memory-free scribbling were also included. FMRI was run before training and after training. Remarkably, V1 of this congenitally blind individual, which before training exhibited noisy, immature, and non-specific responses, after training produced full-fledged response time-courses specific to the tactile-memory drawing task. The results reveal the operation of a rapid training-based plasticity mechanism that recruits the resources of V1 in the process of learning to draw. The learning paradigm allowed us to investigate for the first time the evolution of plastic re-assignment in V1 in a congenitally blind subject. These findings are consistent with a non-visual memory involvement of V1, and specifically imply that the observed cortical reorganization can be empowered by the process of learning to draw. PMID:22593738

Drawing enhances cross-modal memory plasticity in the human brain: a case study in a totally blind adult.

PubMed

Likova, Lora T

2012-01-01

In a memory-guided drawing task under blindfolded conditions, we have recently used functional Magnetic Resonance Imaging (fMRI) to demonstrate that the primary visual cortex (V1) may operate as the visuo-spatial buffer, or "sketchpad," for working memory. The results implied, however, a modality-independent or amodal form of its operation. In the present study, to validate the role of V1 in non-visual memory, we eliminated not only the visual input but all levels of visual processing by replicating the paradigm in a congenitally blind individual. Our novel Cognitive-Kinesthetic method was used to train this totally blind subject to draw complex images guided solely by tactile memory. Control tasks of tactile exploration and memorization of the image to be drawn, and memory-free scribbling were also included. FMRI was run before training and after training. Remarkably, V1 of this congenitally blind individual, which before training exhibited noisy, immature, and non-specific responses, after training produced full-fledged response time-courses specific to the tactile-memory drawing task. The results reveal the operation of a rapid training-based plasticity mechanism that recruits the resources of V1 in the process of learning to draw. The learning paradigm allowed us to investigate for the first time the evolution of plastic re-assignment in V1 in a congenitally blind subject. These findings are consistent with a non-visual memory involvement of V1, and specifically imply that the observed cortical reorganization can be empowered by the process of learning to draw.

Processing of form stimuli presented unilaterally in humans, chimpanzees (Pan troglodytes), and monkeys (Macaca mulatta)

NASA Technical Reports Server (NTRS)

Hopkins, William D.; Washburn, David A.; Rumbaugh, Duane M.

1990-01-01

Visual forms were unilaterally presented using a video-task paradigm to ten humans, chimpanzees, and two rhesus monkeys to determine whether hemispheric advantages existed in the processing of these stimuli. Both accuracy and reaction time served as dependent measures. For the chimpanzees, a significant right hemisphere advantage was found within the first three test sessions. The humans and monkeys failed to show a hemispheric advantage as determined by accuracy scores. Analysis of reaction time data revealed a significant left hemisphere advantage for the monkeys. A visual half-field x block interaction was found for the chimpanzees, with a significant left visual field advantage in block two, whereas a right visual field advantage was found in block four. In the human subjects, a left visual field advantage was found in block three when they used their right hands to respond. The results are discussed in relation to recent reports of hemispheric advantages for nonhuman primates.

The Prevalence of Visual Acuity Impairment among School Children at Arada Subcity Primary Schools in Addis Ababa, Ethiopia.

PubMed

Darge, Haile Fentahun; Shibru, Getahun; Mulugeta, Abiy; Dagnachew, Yinebeb Mezgebu

2017-01-01

Visual impairment and blindness are major public health problems in developing countries where there is no enough health-care service. To determine the prevalence of visual impairment among school children. A school-based cross-sectional study was conducted between 15 June 2015 and 30 November 2015 at Arada subcity primary schools, Addis Ababa, Ethiopia. Two schools were selected randomly, and 378 students were screened from grades 1 to 8 using systematic random sampling method. Snellen chart was used for visual acuity test. Students who had visual acuity of ≤6/12 were further examined by an ophthalmologist to diagnose the reason for low vision. Data was analyzed using SPSS version 20. A total of 378 students were screened, and 192 (50.8%) were females and the remaining 186 (49.2%) were males. The prevalence of visual impairment (VA) of ≤6/12 on either eye was 5.8%, VA < 6/18 on either eye was 1.1%, and VA < 6/18 on the better eye was 0.53%. In this study, color blindness [OR: 19.65, 95% CI (6.01-64.33)] was significantly associated with visual acuity impairment. The prevalence of visual impairment among school children in the study area was 5.8% and school screening is recommended.

The Notch/Hes1 pathway sustains NF-κB activation through CYLD repression in T cell leukemia

PubMed Central

Espinosa, Lluis; Cathelin, Severine; D’Altri, Teresa; Trimarchi, Thomas; Statnikov, Alexander; Guiu, Jordi; Rodilla, Veronica; Inglés-Esteve, Julia; Nomdedeu, Josep; Bellosillo, Beatriz; Besses, Carles; Abdel-Wahab, Omar; Kucine, Nicole; Sun, Shao-Cong; Song, Guangchan; Mullighan, Charles C.; Levine, Ross L.; Rajewsky, Klaus; Aifantis, Iannis; Bigas, Anna

2010-01-01

SUMMARY It was previously shown that the NF-κB pathway is downstream of oncogenic Notch1 in T cell acute lymphoblastic leukemia (T-ALL). Here we visualize Notch-induced NF-κB activation using both human T-ALL cell lines and animal models. We demonstrate that Hes1, a canonical Notch target and transcriptional repressor, is responsible for sustaining IKK activation in T-ALL. Hes1 exerts its effects by repressing the deubiquitinase CYLD, a negative IKK complex regulator. CYLD expression was found to be significantly suppressed in primary T-ALL. Finally, we demonstrate that IKK inhibition is a promising option for the targeted therapy of T-ALL as specific suppression of IKK expression and function affected both the survival of human T-ALL cells and the maintenance of the disease in vivo. PMID:20832754

The Notch/Hes1 pathway sustains NF-κB activation through CYLD repression in T cell leukemia.

PubMed

Espinosa, Lluis; Cathelin, Severine; D'Altri, Teresa; Trimarchi, Thomas; Statnikov, Alexander; Guiu, Jordi; Rodilla, Veronica; Inglés-Esteve, Julia; Nomdedeu, Josep; Bellosillo, Beatriz; Besses, Carles; Abdel-Wahab, Omar; Kucine, Nicole; Sun, Shao-Cong; Song, Guangchan; Mullighan, Charles C; Levine, Ross L; Rajewsky, Klaus; Aifantis, Iannis; Bigas, Anna

2010-09-14

It was previously shown that the NF-κB pathway is downstream of oncogenic Notch1 in T cell acute lymphoblastic leukemia (T-ALL). Here, we visualize Notch-induced NF-κB activation using both human T-ALL cell lines and animal models. We demonstrate that Hes1, a canonical Notch target and transcriptional repressor, is responsible for sustaining IKK activation in T-ALL. Hes1 exerts its effects by repressing the deubiquitinase CYLD, a negative IKK complex regulator. CYLD expression was found to be significantly suppressed in primary T-ALL. Finally, we demonstrate that IKK inhibition is a promising option for the targeted therapy of T-ALL as specific suppression of IKK expression and function affected both the survival of human T-ALL cells and the maintenance of the disease in vivo. Copyright © 2010 Elsevier Inc. All rights reserved.

Phonological Processing in Human Auditory Cortical Fields

PubMed Central

Woods, David L.; Herron, Timothy J.; Cate, Anthony D.; Kang, Xiaojian; Yund, E. W.

2011-01-01

We used population-based cortical-surface analysis of functional magnetic imaging data to characterize the processing of consonant–vowel–consonant syllables (CVCs) and spectrally matched amplitude-modulated noise bursts (AMNBs) in human auditory cortex as subjects attended to auditory or visual stimuli in an intermodal selective attention paradigm. Average auditory cortical field (ACF) locations were defined using tonotopic mapping in a previous study. Activations in auditory cortex were defined by two stimulus-preference gradients: (1) Medial belt ACFs preferred AMNBs and lateral belt and parabelt fields preferred CVCs. This preference extended into core ACFs with medial regions of primary auditory cortex (A1) and the rostral field preferring AMNBs and lateral regions preferring CVCs. (2) Anterior ACFs showed smaller activations but more clearly defined stimulus preferences than did posterior ACFs. Stimulus preference gradients were unaffected by auditory attention suggesting that ACF preferences reflect the automatic processing of different spectrotemporal sound features. PMID:21541252

Simulator of human visual perception

NASA Astrophysics Data System (ADS)

Bezzubik, Vitalii V.; Belashenkov, Nickolai R.

2016-04-01

Difference of Circs (DoC) model allowing to simulate the response of neurons - ganglion cells as a reaction to stimuli is represented and studied in relation with representation of receptive fields of human retina. According to this model the response of neurons is reduced to execution of simple arithmetic operations and the results of these calculations well correlate with experimental data in wide range of stimuli parameters. The simplicity of the model and reliability of reproducing of responses allow to propose the conception of a device which can simulate the signals generated by ganglion cells as a reaction to presented stimuli. The signals produced according to DoC model are considered as a result of primary processing of information received from receptors independently of their type and may be sent to higher levels of nervous system of living creatures for subsequent processing. Such device may be used as a prosthesis for disabled organ.

Utilizing Primary Sources as Building Blocks for Literacy.

ERIC Educational Resources Information Center

Massich, Mary; Munoz, Eric

1996-01-01

Describes instructional strategies using primary sources in middle school history instruction. Maintains that students need to make critical, personal connections to material before they understand it. The strategies examined use visual aids, living history presentations, realia, music, and primary documents. (MJP)

Synaptic Mechanisms Generating Orientation Selectivity in the ON Pathway of the Rabbit Retina

PubMed Central

Venkataramani, Sowmya

2016-01-01

Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input. SIGNIFICANCE STATEMENT A core goal for visual neuroscientists is to understand how neural circuits at each stage of the visual system extract and encode features from the visual scene. This study documents a novel type of orientation-selective ganglion cell in the retina and shows that the receptive field structure is remarkably similar to that of simple cells in primary visual cortex. However, the data indicate that, unlike in the cortex, orientation selectivity in the retina depends on the activity of inhibitory interneurons. The results further reveal the physiological basis for feature detection in the visual system, elucidate the synaptic mechanisms that generate orientation selectivity at an early stage of visual processing, and illustrate a novel role for NMDA receptors in retinal processing. PMID:26985041

Synaptic Mechanisms Generating Orientation Selectivity in the ON Pathway of the Rabbit Retina.

PubMed

Venkataramani, Sowmya; Taylor, W Rowland

2016-03-16

Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input. A core goal for visual neuroscientists is to understand how neural circuits at each stage of the visual system extract and encode features from the visual scene. This study documents a novel type of orientation-selective ganglion cell in the retina and shows that the receptive field structure is remarkably similar to that of simple cells in primary visual cortex. However, the data indicate that, unlike in the cortex, orientation selectivity in the retina depends on the activity of inhibitory interneurons. The results further reveal the physiological basis for feature detection in the visual system, elucidate the synaptic mechanisms that generate orientation selectivity at an early stage of visual processing, and illustrate a novel role for NMDA receptors in retinal processing. Copyright © 2016 the authors 0270-6474/16/363336-14$15.00/0.

Learning Enhances Sensory and Multiple Non-sensory Representations in Primary Visual Cortex

PubMed Central

Poort, Jasper; Khan, Adil G.; Pachitariu, Marius; Nemri, Abdellatif; Orsolic, Ivana; Krupic, Julija; Bauza, Marius; Sahani, Maneesh; Keller, Georg B.; Mrsic-Flogel, Thomas D.; Hofer, Sonja B.

2015-01-01

Summary We determined how learning modifies neural representations in primary visual cortex (V1) during acquisition of a visually guided behavioral task. We imaged the activity of the same layer 2/3 neuronal populations as mice learned to discriminate two visual patterns while running through a virtual corridor, where one pattern was rewarded. Improvements in behavioral performance were closely associated with increasingly distinguishable population-level representations of task-relevant stimuli, as a result of stabilization of existing and recruitment of new neurons selective for these stimuli. These effects correlated with the appearance of multiple task-dependent signals during learning: those that increased neuronal selectivity across the population when expert animals engaged in the task, and those reflecting anticipation or behavioral choices specifically in neuronal subsets preferring the rewarded stimulus. Therefore, learning engages diverse mechanisms that modify sensory and non-sensory representations in V1 to adjust its processing to task requirements and the behavioral relevance of visual stimuli. PMID:26051421

Effects of internal limiting membrane peeling during vitrectomy for macula-off primary rhegmatogenous retinal detachment.

PubMed

Blanco-Teijeiro, María José; Bande Rodriguez, Manuel; Mansilla Cuñarro, Raquel; Paniagua Fernández, Laura; Ruiz-Oliva Ruiz, Francisco; Piñeiro Ces, Antonio

2018-03-01

To determine the effectiveness of internal limiting membrane peeling during vitrectomy for macula-off primary rhegmatogenous retinal detachment in the prevention of postoperative epiretinal membrane formation and achievement of good visual outcomes and to identify preoperative and intraoperative risk factors for epiretinal membrane formation. We retrospectively analyzed data from 62 eyes of 62 consecutive patients with macula-off primary rhegmatogenous retinal detachment who underwent vitrectomy with (n = 30) or without (n = 32) internal limiting membrane peeling between January 2014 and March 2016 and were followed up for at least 12 months. The effects of internal limiting membrane peeling on visual outcomes and postoperative recovery of the macular structure were determined. We subsequently divided patients into an epiretinal membrane group and a non-epiretinal membrane group and assessed the effects of various preoperative and intraoperative factors on postoperative epiretinal membrane formation. Postoperative epiretinal membrane developed in 10 patients in the no internal limiting membrane peeling group and three patients in the internal limiting membrane peeling group. Postoperative visual acuity significantly improved in both groups. Epiretinal membrane formation was found to be correlated with a higher number of retinal breaks. Our results suggest that internal limiting membrane peeling during macula-off primary rhegmatogenous retinal detachment surgery can reduce the occurrence of postoperative epiretinal membrane, is safe, and results in favorable visual outcomes.

Oscillatory encoding of visual stimulus familiarity.

PubMed

Kissinger, Samuel T; Pak, Alexandr; Tang, Yu; Masmanidis, Sotiris C; Chubykin, Alexander A

2018-06-18

Familiarity of the environment changes the way we perceive and encode incoming information. However, the neural substrates underlying this phenomenon are poorly understood. Here we describe a new form of experience-dependent low frequency oscillations in the primary visual cortex (V1) of awake adult male mice. The oscillations emerged in visually evoked potentials (VEPs) and single-unit activity following repeated visual stimulation. The oscillations were sensitive to the spatial frequency content of a visual stimulus and required the muscarinic acetylcholine receptors (mAChRs) for their induction and expression. Finally, ongoing visually evoked theta (4-6 Hz) oscillations boost the VEP amplitude of incoming visual stimuli if the stimuli are presented at the high excitability phase of the oscillations. Our results demonstrate that an oscillatory code can be used to encode familiarity and serves as a gate for oncoming sensory inputs. Significance Statement. Previous experience can influence the processing of incoming sensory information by the brain and alter perception. However, the mechanistic understanding of how this process takes place is lacking. We have discovered that persistent low frequency oscillations in the primary visual cortex encode information about familiarity and the spatial frequency of the stimulus. These familiarity evoked oscillations influence neuronal responses to the oncoming stimuli in a way that depends on the oscillation phase. Our work demonstrates a new mechanism of visual stimulus feature detection and learning. Copyright © 2018 the authors.

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.

Monocular and binocular visual impairment in the UK Biobank study: prevalence, associations and diagnoses.

PubMed

McKibbin, Martin; Farragher, Tracey M; Shickle, Darren

2018-01-01

To determine the prevalence of, associations with and diagnoses leading to mild visual impairment or worse (logMAR >0.3) in middle-aged adults in the UK Biobank study. Prevalence estimates for monocular and binocular visual impairment were determined for the UK Biobank participants with fundus photographs and spectral domain optical coherence tomography images. Associations with socioeconomic, biometric, lifestyle and medical variables were investigated for cases with visual impairment and matched controls, using multinomial logistic regression models. Self-reported eye history and image grading results were used to identify the primary diagnoses leading to visual impairment for a sample of 25% of cases. For the 65 033 UK Biobank participants, aged 40-69 years and with fundus images, 6682 (10.3%) and 1677 (2.6%) had mild visual impairment or worse in one or both eyes, respectively. Increasing deprivation, age and ethnicity were independently associated with both monocular and binocular visual impairment. No primary diagnosis for the recorded level of visual impairment could be identified for 49.8% of eyes. The most common identifiable diagnoses leading to visual impairment were cataract, amblyopia, uncorrected refractive error and vitreoretinal interface abnormalities. The prevalence of visual impairment in the UK Biobank study cohort is lower than for population-based studies from other industrialised countries. Monocular and binocular visual impairment are associated with increasing deprivation, age and ethnicity. The UK Biobank dataset does not allow confident identification of the causes of visual impairment, and the results may not be applicable to the wider UK population.

Monocular and binocular visual impairment in the UK Biobank study: prevalence, associations and diagnoses

PubMed Central

Farragher, Tracey M; Shickle, Darren

2018-01-01

Objective To determine the prevalence of, associations with and diagnoses leading to mild visual impairment or worse (logMAR >0.3) in middle-aged adults in the UK Biobank study. Methods and analysis Prevalence estimates for monocular and binocular visual impairment were determined for the UK Biobank participants with fundus photographs and spectral domain optical coherence tomography images. Associations with socioeconomic, biometric, lifestyle and medical variables were investigated for cases with visual impairment and matched controls, using multinomial logistic regression models. Self-reported eye history and image grading results were used to identify the primary diagnoses leading to visual impairment for a sample of 25% of cases. Results For the 65 033 UK Biobank participants, aged 40–69 years and with fundus images, 6682 (10.3%) and 1677 (2.6%) had mild visual impairment or worse in one or both eyes, respectively. Increasing deprivation, age and ethnicity were independently associated with both monocular and binocular visual impairment. No primary diagnosis for the recorded level of visual impairment could be identified for 49.8% of eyes. The most common identifiable diagnoses leading to visual impairment were cataract, amblyopia, uncorrected refractive error and vitreoretinal interface abnormalities. Conclusions The prevalence of visual impairment in the UK Biobank study cohort is lower than for population-based studies from other industrialised countries. Monocular and binocular visual impairment are associated with increasing deprivation, age and ethnicity. The UK Biobank dataset does not allow confident identification of the causes of visual impairment, and the results may not be applicable to the wider UK population. PMID:29657974

Efficacy of human papillomavirus-based screen-and-treat for cervical cancer prevention among HIV-infected women.

PubMed

Kuhn, Louise; Wang, Chunhui; Tsai, Wei-Yann; Wright, Thomas C; Denny, Lynette

2010-10-23

Cervical cancer prevention should be provided as part of primary healthcare services for HIV-infected women but conventional screening programs are difficult to implement in low-resource settings. Here, we evaluate the efficacy among HIV-infected women of a simpler, screen-and-treat strategy in which all women with a positive screening test are treated with cryotherapy. We conducted a randomized clinical trial of two screen-and-treat strategies among 6555 women in Cape Town, South Africa, among whom 956 were HIV-positive. Women were randomized to screen-and-treat utilizing either human papillomavirus DNA testing or visual inspection with acetic acid as the screening method or to a control group. Women were followed for up to 36 months after randomization with colposcopy and biopsy to determine the study endpoint of cervical intraepithelial neoplasia grade 2 or higher. In the control group, HIV-positive women had higher rates of cervical intraepithelial neoplasia grade 2 or higher detected by 36 months (14.9%) than HIV-negative women (4.6%) (P = 0.0006). Screen-and-treat utilizing human papillomavirus DNA testing significantly reduced cervical intraepithelial neoplasia grade 2 or higher through 36 months in both HIV-positive (relative risk = 0.20, 95% confidence interval 0.06-0.69) and HIV-negative women (relative risk = 0.31, 95% confidence interval 0.20-0.50). Reductions in the visual inspection with acetic acid-and-treat group were less marked. Complications of cryotherapy were mostly minor and did not differ in frequency between HIV-positive and HIV-negative women. Screen-and-treat using human papillomavirus testing is a simple and effective method to reduce high-grade cervical cancer precursors in HIV-infected women.

Effet de l'encombrement visuel de l'ecran primaire de vol sur la performance du pilote, la charge de travail et le parcours visuel

NASA Astrophysics Data System (ADS)

Doyon-Poulin, Philippe

Flight deck of 21st century commercial aircrafts does not look like the one the Wright brothers used for their first flight. The rapid growth of civilian aviation resulted in an increase in the number of flight deck instruments and of their complexity, in order to complete a safe and ontime flight. However, presenting an abundance of visual information using visually cluttered flight instruments might reduce the pilot's flight performance. Visual clutter has received an increased interest by the aerospace community to understand the effects of visual density and information overload on pilots' performance. Aerospace regulations demand to minimize visual clutter of flight deck displays. Past studies found a mixed effect of visual clutter of the primary flight display on pilots' technical flight performance. More research is needed to better understand this subject. In this thesis, we did an experimental study in a flight simulator to test the effects of visual clutter of the primary flight display on the pilot's technical flight performance, mental workload and gaze pattern. First, we identified a gap in existing definitions of visual clutter and we proposed a new definition relevant to the aerospace community that takes into account the context of use of the display. Then, we showed that past research on the effects of visual clutter of the primary flight display on pilots' performance did not manipulate the variable of visual clutter in a similar manner. Past research changed visual clutter at the same time than the flight guidance function. Using a different flight guidance function between displays might have masked the effect of visual clutter on pilots' performance. To solve this issue, we proposed three requirements that all tested displays must satisfy to assure that only the variable of visual clutter is changed during study while leaving other variables unaffected. Then, we designed three primary flight displays with a different visual clutter level (low, medium, high) but with the same flight guidance function, by respecting the previous requirements. Twelve pilots, with a mean experience of over 4000 total flight hours, completed an instrument landing in a flight simulator using all three displays for a total of nine repetitions. Our results showed that pilots reported lower workload level and had better lateral precision during the approach using the medium-clutter display compared to the low- and high-clutter displays. Also, pilots reported that the medium-clutter display was the most useful for the flight task compared to the two other displays. Eye tracker results showed that pilots' gaze pattern was less efficient for the high-clutter display compared to the low- and medium-clutter displays. Overall, these new experimental results emphasize the importance of optimizing visual clutter of flight displays as it affects both objective and subjective performance of experienced pilots in their flying task. This thesis ends with practical recommendations to help designers optimize visual clutter of displays used for man-machine interface.