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Sample records for optimal stimulus eliciting

  1. Stimulus Duration Preference at Electrode Sites Yielding Elicited Behavior

    NASA Technical Reports Server (NTRS)

    Cox, V. C.

    1970-01-01

    The latency to display eating or drinking during hypothalamic stimulation was compared with the preferred duration of the same stimulus intensity in a self-stimulation situation. All the animals preferred longer stimulus durations than those required to elicit eating or drinking

  2. Optimizing Stimulus Repetition Rate for Recording Ocular Vestibular Evoked Myogenic Potential Elicited by Air-Conduction Tone Bursts of 500 Hz

    PubMed Central

    Singh, Niraj Kumar; Kadisonga, Peter; Ashitha, Palliyath

    2014-01-01

    Amidst several publications reporting the effects of stimulus-related parameters on ocular vestibular evoked myogenic potential (oVEMP), the effect of the repetition rate on oVEMP responses has largely gone unexplored. Studies have used a repetition rate of ~5.1 Hz mainly due to a presumption that oVEMP, like cervical VEMP, should produce best responses for ~5 Hz, although there is paucity of experimental evidence to support this hypothesis. 52 healthy individuals in the age range of 17-35 years underwent air-conduction oVEMP elicited by 500 Hz tone-bursts using seven different repetition rates (3.1, 5.1, 10.1, 15.1, 20.1, 25.1 and 30.1 Hz). The results revealed a tendency for prolongation of latencies and reduction in amplitude with increasing repetition rate. However, significantly longer latencies were observed only for 20.1 Hz and larger amplitudes for 3.1 and 5.1 Hz (P<0.05). There was no significant difference between the rates of 3.1 Hz and 5.1 Hz. However 3.1 Hz produced poorer signal-to-noise ratio and required considerably longer time and thereby had lesser efficiency than 5.1 Hz (P<0.05). This would also result in higher fatigue and irritation levels considering the physical act of maintaining a supero-medial gaze. Thus the use of 5.1 Hz is recommended for clinical recording of oVEMP. PMID:26557349

  3. Optimal Stimulus Shapes for Neuronal Excitation

    PubMed Central

    Forger, Daniel B.; Paydarfar, David; Clay, John R.

    2011-01-01

    An important problem in neuronal computation is to discern how features of stimuli control the timing of action potentials. One aspect of this problem is to determine how an action potential, or spike, can be elicited with the least energy cost, e.g., a minimal amount of applied current. Here we show in the Hodgkin & Huxley model of the action potential and in experiments on squid giant axons that: 1) spike generation in a neuron can be highly discriminatory for stimulus shape and 2) the optimal stimulus shape is dependent upon inputs to the neuron. We show how polarity and time course of post-synaptic currents determine which of these optimal stimulus shapes best excites the neuron. These results are obtained mathematically using the calculus of variations and experimentally using a stochastic search methodology. Our findings reveal a surprising complexity of computation at the single cell level that may be relevant for understanding optimization of signaling in neurons and neuronal networks. PMID:21760759

  4. Adaptive stimulus optimization for sensory systems neuroscience.

    PubMed

    DiMattina, Christopher; Zhang, Kechen

    2013-01-01

    In this paper, we review several lines of recent work aimed at developing practical methods for adaptive on-line stimulus generation for sensory neurophysiology. We consider various experimental paradigms where on-line stimulus optimization is utilized, including the classical optimal stimulus paradigm where the goal of experiments is to identify a stimulus which maximizes neural responses, the iso-response paradigm which finds sets of stimuli giving rise to constant responses, and the system identification paradigm where the experimental goal is to estimate and possibly compare sensory processing models. We discuss various theoretical and practical aspects of adaptive firing rate optimization, including optimization with stimulus space constraints, firing rate adaptation, and possible network constraints on the optimal stimulus. We consider the problem of system identification, and show how accurate estimation of non-linear models can be highly dependent on the stimulus set used to probe the network. We suggest that optimizing stimuli for accurate model estimation may make it possible to successfully identify non-linear models which are otherwise intractable, and summarize several recent studies of this type. Finally, we present a two-stage stimulus design procedure which combines the dual goals of model estimation and model comparison and may be especially useful for system identification experiments where the appropriate model is unknown beforehand. We propose that fast, on-line stimulus optimization enabled by increasing computer power can make it practical to move sensory neuroscience away from a descriptive paradigm and toward a new paradigm of real-time model estimation and comparison.

  5. Adaptive stimulus optimization for sensory systems neuroscience

    PubMed Central

    DiMattina, Christopher; Zhang, Kechen

    2013-01-01

    In this paper, we review several lines of recent work aimed at developing practical methods for adaptive on-line stimulus generation for sensory neurophysiology. We consider various experimental paradigms where on-line stimulus optimization is utilized, including the classical optimal stimulus paradigm where the goal of experiments is to identify a stimulus which maximizes neural responses, the iso-response paradigm which finds sets of stimuli giving rise to constant responses, and the system identification paradigm where the experimental goal is to estimate and possibly compare sensory processing models. We discuss various theoretical and practical aspects of adaptive firing rate optimization, including optimization with stimulus space constraints, firing rate adaptation, and possible network constraints on the optimal stimulus. We consider the problem of system identification, and show how accurate estimation of non-linear models can be highly dependent on the stimulus set used to probe the network. We suggest that optimizing stimuli for accurate model estimation may make it possible to successfully identify non-linear models which are otherwise intractable, and summarize several recent studies of this type. Finally, we present a two-stage stimulus design procedure which combines the dual goals of model estimation and model comparison and may be especially useful for system identification experiments where the appropriate model is unknown beforehand. We propose that fast, on-line stimulus optimization enabled by increasing computer power can make it practical to move sensory neuroscience away from a descriptive paradigm and toward a new paradigm of real-time model estimation and comparison. PMID:23761737

  6. Stimulus-Elicited Connectivity Influences Resting-State Connectivity Years Later in Human Development: A Prospective Study

    PubMed Central

    Gee, Dylan Grace; Goff, Bonnie; Flannery, Jessica; Telzer, Eva; Humphreys, Kathryn Leigh; Lumian, Daniel Stephen; Fareri, Dominic Stephen; Caldera, Christina; Tottenham, Nim

    2016-01-01

    Although the functional architecture of the brain is indexed by resting-state connectivity networks, little is currently known about the mechanisms through which these networks assemble into stable mature patterns. The current study posits and tests the long-term phasic molding hypothesis that resting-state networks are gradually shaped by recurring stimulus-elicited connectivity across development by examining how both stimulus-elicited and resting-state functional connections of the human brain emerge over development at the systems level. Using a sequential design following 4- to 18-year-olds over a 2 year period, we examined the predictive associations between stimulus-elicited and resting-state connectivity in amygdala-cortical circuitry as an exemplar case (given this network's protracted development across these ages). Age-related changes in amygdala functional connectivity converged on the same regions of medial prefrontal cortex (mPFC) and inferior frontal gyrus when elicited by emotional stimuli and when measured at rest. Consistent with the long-term phasic molding hypothesis, prospective analyses for both connections showed that the magnitude of an individual's stimulus-elicited connectivity unidirectionally predicted resting-state functional connectivity 2 years later. For the amygdala-mPFC connection, only stimulus-elicited connectivity during childhood and the transition to adolescence shaped future resting-state connectivity, consistent with a sensitive period ending with adolescence for the amygdala-mPFC circuit. Together, these findings suggest that resting-state functional architecture may arise from phasic patterns of functional connectivity elicited by environmental stimuli over the course of development on the order of years. SIGNIFICANCE STATEMENT A fundamental issue in understanding the ontogeny of brain function is how resting-state (intrinsic) functional networks emerge and relate to stimulus-elicited functional connectivity. Here, we

  7. Neural Basis of Stimulus-Angle-Dependent Motor Control of Wind-Elicited Walking Behavior in the Cricket Gryllus bimaculatus

    PubMed Central

    Oe, Momoko; Ogawa, Hiroto

    2013-01-01

    Crickets exhibit oriented walking behavior in response to air-current stimuli. Because crickets move in the opposite direction from the stimulus source, this behavior is considered to represent ‘escape behavior’ from an approaching predator. However, details of the stimulus-angle-dependent control of locomotion during the immediate phase, and the neural basis underlying the directional motor control of this behavior remain unclear. In this study, we used a spherical-treadmill system to measure locomotory parameters including trajectory, turn angle and velocity during the immediate phase of responses to air-puff stimuli applied from various angles. Both walking direction and turn angle were correlated with stimulus angle, but their relationships followed different rules. A shorter stimulus also induced directionally-controlled walking, but reduced the yaw rotation in stimulus-angle-dependent turning. These results suggest that neural control of the turn angle requires different sensory information than that required for oriented walking. Hemi-severance of the ventral nerve cords containing descending axons from the cephalic to the prothoracic ganglion abolished stimulus-angle-dependent control, indicating that this control required descending signals from the brain. Furthermore, we selectively ablated identified ascending giant interneurons (GIs) in vivo to examine their functional roles in wind-elicited walking. Ablation of GI8-1 diminished control of the turn angle and decreased walking distance in the initial response. Meanwhile, GI9-1b ablation had no discernible effect on stimulus-angle-dependent control or walking distance, but delayed the reaction time. These results suggest that the ascending signals conveyed by GI8-1 are required for turn-angle control and maintenance of walking behavior, and that GI9-1b is responsible for rapid initiation of walking. It is possible that individual types of GIs separately supply the sensory signals required to control

  8. Improving balance function using vestibular stochastic resonance: optimizing stimulus characteristics.

    PubMed

    Mulavara, Ajitkumar P; Fiedler, Matthew J; Kofman, Igor S; Wood, Scott J; Serrador, Jorge M; Peters, Brian; Cohen, Helen S; Reschke, Millard F; Bloomberg, Jacob J

    2011-04-01

    Stochastic resonance (SR) is a phenomenon whereby the response of a non-linear system to a weak periodic input signal is optimized by the presence of a particular non-zero level of noise. Stochastic resonance using imperceptible stochastic vestibular electrical stimulation, when applied to normal young and elderly subjects, has been shown to significantly improve ocular stabilization reflexes in response to whole-body tilt; improved balance performance during postural disturbances and optimize covariance between the weak input periodic signals introduced via venous blood pressure receptors and the heart rate responses. In our study, 15 subjects stood on a compliant surface with their eyes closed. They were given low-amplitude binaural bipolar stochastic electrical stimulation of the vestibular organs in two frequency ranges of 1-2 and 0-30 Hz over the amplitude range of 0 to ±700 μA. Subjects were instructed to maintain an upright stance during 43-s trials, which consisted of baseline (zero amplitude) and stimulation (non-zero amplitude) periods. Measures of stability of the head and trunk using inertial motion unit sensors attached to these segments and the whole body using a force plate were measured and quantified in the mediolateral plane. Using a multivariate optimization criterion, our results show that the low levels of vestibular stimulation given to the vestibular organs improved balance performance in normal healthy subjects in the range of 5-26% consistent with the stochastic resonance phenomenon. In our study, 8 of 15 and 10 of 15 subjects were responsive for the 1-2- and 0-30-Hz stimulus signals, respectively. The improvement in balance performance did not differ significantly between the stimulations in the two frequency ranges. The amplitude of optimal stimulus for improving balance performance was predominantly in the range of ±100 to ±400 μA. A device based on SR stimulation of the vestibular system might be useful as either a training

  9. Optimal stimulus scheduling for active estimation of evoked brain networks

    NASA Astrophysics Data System (ADS)

    Kafashan, MohammadMehdi; Ching, ShiNung

    2015-12-01

    Objective. We consider the problem of optimal probing to learn connections in an evoked dynamic network. Such a network, in which each edge measures an input-output relationship between sites in sensor/actuator-space, is relevant to emerging applications in neural mapping and neural connectivity estimation. Approach. We show that the problem of scheduling nodes to a probe (i.e., stimulate) amounts to a problem of optimal sensor scheduling. Main results. By formulating the evoked network in state-space, we show that the solution to the greedy probing strategy has a convenient form and, under certain conditions, is optimal over a finite horizon. We adopt an expectation maximization technique to update the state-space parameters in an online fashion and demonstrate the efficacy of the overall approach in a series of detailed numerical examples. Significance. The proposed method provides a principled means to actively probe time-varying connections in neuronal networks. The overall method can be implemented in real time and is particularly well-suited to applications in stimulation-based cortical mapping in which the underlying network dynamics are changing over time.

  10. Visual stimulus characteristics that elicit tracking and striking in the praying mantises Parasphendale affinis, Popa spurca and Sphodromantis lineola.

    PubMed

    Prete, Frederick R; Theis, Robert; Dominguez, Salina; Bogue, Wil

    2013-12-01

    We tested three species of praying mantis, Parasphendale affinis, Popa spurca and Sphodromantis lineola, with computer-generated stimuli that differed in size, contrast, configuration and movement pattern to determine the effects of these parameters on visual tracking and striking behavior. Overall, black disks moving erratically against a white background were strong releasers of both behaviors. When stimulus presentation order was randomized by size, P. affinis and P. spurca struck at progressively higher rates as the stimuli enlarged up to 44 deg; S. lineola struck most at intermediate sized (10-20 deg) disks. When disks were size-ordered from small to large, P. affinis and S. lineola struck at the smaller disks at higher rates; however, when the order was reversed, the early appearance of large disks suppressed subsequent responses to the smaller disks. Stimulus order did not differentially affect the responses of P. spurca. All species responded at higher rates to black disks moving against a white background versus the reverse. However, only P. spurca and S. lineola responded at higher rates to relatively darker grey disks, only P. affinis responded to mottled grey disks moving against an identically patterned background, and only P. spurca struck more frequently in response to rectangular stimuli oriented parallel (versus orthogonal) to their direction of movement. In conjunction with data on other species, these results support the hypothesis that praying mantises recognize prey based on assessment of several category-specific, spatiotemporal features, e.g. size, contrast, speed, movement pattern and leading edge length. PMID:24031054

  11. Eliciting naturalistic cortical responses with a sensory prosthesis via optimized microstimulation

    NASA Astrophysics Data System (ADS)

    Choi, John S.; Brockmeier, Austin J.; McNiel, David B.; von Kraus, Lee M.; Príncipe, José C.; Francis, Joseph T.

    2016-10-01

    Objective. Lost sensations, such as touch, could one day be restored by electrical stimulation along the sensory neural pathways. Such stimulation, when informed by electronic sensors, could provide naturalistic cutaneous and proprioceptive feedback to the user. Perceptually, microstimulation of somatosensory brain regions produces localized, modality-specific sensations, and several spatiotemporal parameters have been studied for their discernibility. However, systematic methods for encoding a wide array of naturally occurring stimuli into biomimetic percepts via multi-channel microstimulation are lacking. More specifically, generating spatiotemporal patterns for explicitly evoking naturalistic neural activation has not yet been explored. Approach. We address this problem by first modeling the dynamical input-output relationship between multichannel microstimulation and downstream neural responses, and then optimizing the input pattern to reproduce naturally occurring touch responses as closely as possible. Main results. Here we show that such optimization produces responses in the S1 cortex of the anesthetized rat that are highly similar to natural, tactile-stimulus-evoked counterparts. Furthermore, information on both pressure and location of the touch stimulus was found to be highly preserved. Significance. Our results suggest that the currently presented stimulus optimization approach holds great promise for restoring naturalistic levels of sensation.

  12. Online stimulus optimization rapidly reveals multidimensional selectivity in auditory cortical neurons.

    PubMed

    Chambers, Anna R; Hancock, Kenneth E; Sen, Kamal; Polley, Daniel B

    2014-07-01

    Neurons in sensory brain regions shape our perception of the surrounding environment through two parallel operations: decomposition and integration. For example, auditory neurons decompose sounds by separately encoding their frequency, temporal modulation, intensity, and spatial location. Neurons also integrate across these various features to support a unified perceptual gestalt of an auditory object. At higher levels of a sensory pathway, neurons may select for a restricted region of feature space defined by the intersection of multiple, independent stimulus dimensions. To further characterize how auditory cortical neurons decompose and integrate multiple facets of an isolated sound, we developed an automated procedure that manipulated five fundamental acoustic properties in real time based on single-unit feedback in awake mice. Within several minutes, the online approach converged on regions of the multidimensional stimulus manifold that reliably drove neurons at significantly higher rates than predefined stimuli. Optimized stimuli were cross-validated against pure tone receptive fields and spectrotemporal receptive field estimates in the inferior colliculus and primary auditory cortex. We observed, from midbrain to cortex, increases in both level invariance and frequency selectivity, which may underlie equivalent sparseness of responses in the two areas. We found that onset and steady-state spike rates increased proportionately as the stimulus was tailored to the multidimensional receptive field. By separately evaluating the amount of leverage each sound feature exerted on the overall firing rate, these findings reveal interdependencies between stimulus features as well as hierarchical shifts in selectivity and invariance that may go unnoticed with traditional approaches. PMID:24990917

  13. Extracellular voltage threshold settings can be tuned for optimal encoding of movement and stimulus parameters

    NASA Astrophysics Data System (ADS)

    Oby, Emily R.; Perel, Sagi; Sadtler, Patrick T.; Ruff, Douglas A.; Mischel, Jessica L.; Montez, David F.; Cohen, Marlene R.; Batista, Aaron P.; Chase, Steven M.

    2016-06-01

    Objective. A traditional goal of neural recording with extracellular electrodes is to isolate action potential waveforms of an individual neuron. Recently, in brain–computer interfaces (BCIs), it has been recognized that threshold crossing events of the voltage waveform also convey rich information. To date, the threshold for detecting threshold crossings has been selected to preserve single-neuron isolation. However, the optimal threshold for single-neuron identification is not necessarily the optimal threshold for information extraction. Here we introduce a procedure to determine the best threshold for extracting information from extracellular recordings. We apply this procedure in two distinct contexts: the encoding of kinematic parameters from neural activity in primary motor cortex (M1), and visual stimulus parameters from neural activity in primary visual cortex (V1). Approach. We record extracellularly from multi-electrode arrays implanted in M1 or V1 in monkeys. Then, we systematically sweep the voltage detection threshold and quantify the information conveyed by the corresponding threshold crossings. Main Results. The optimal threshold depends on the desired information. In M1, velocity is optimally encoded at higher thresholds than speed; in both cases the optimal thresholds are lower than are typically used in BCI applications. In V1, information about the orientation of a visual stimulus is optimally encoded at higher thresholds than is visual contrast. A conceptual model explains these results as a consequence of cortical topography. Significance. How neural signals are processed impacts the information that can be extracted from them. Both the type and quality of information contained in threshold crossings depend on the threshold setting. There is more information available in these signals than is typically extracted. Adjusting the detection threshold to the parameter of interest in a BCI context should improve our ability to decode motor intent

  14. Extracellular voltage threshold settings can be tuned for optimal encoding of movement and stimulus parameters

    NASA Astrophysics Data System (ADS)

    Oby, Emily R.; Perel, Sagi; Sadtler, Patrick T.; Ruff, Douglas A.; Mischel, Jessica L.; Montez, David F.; Cohen, Marlene R.; Batista, Aaron P.; Chase, Steven M.

    2016-06-01

    Objective. A traditional goal of neural recording with extracellular electrodes is to isolate action potential waveforms of an individual neuron. Recently, in brain-computer interfaces (BCIs), it has been recognized that threshold crossing events of the voltage waveform also convey rich information. To date, the threshold for detecting threshold crossings has been selected to preserve single-neuron isolation. However, the optimal threshold for single-neuron identification is not necessarily the optimal threshold for information extraction. Here we introduce a procedure to determine the best threshold for extracting information from extracellular recordings. We apply this procedure in two distinct contexts: the encoding of kinematic parameters from neural activity in primary motor cortex (M1), and visual stimulus parameters from neural activity in primary visual cortex (V1). Approach. We record extracellularly from multi-electrode arrays implanted in M1 or V1 in monkeys. Then, we systematically sweep the voltage detection threshold and quantify the information conveyed by the corresponding threshold crossings. Main Results. The optimal threshold depends on the desired information. In M1, velocity is optimally encoded at higher thresholds than speed; in both cases the optimal thresholds are lower than are typically used in BCI applications. In V1, information about the orientation of a visual stimulus is optimally encoded at higher thresholds than is visual contrast. A conceptual model explains these results as a consequence of cortical topography. Significance. How neural signals are processed impacts the information that can be extracted from them. Both the type and quality of information contained in threshold crossings depend on the threshold setting. There is more information available in these signals than is typically extracted. Adjusting the detection threshold to the parameter of interest in a BCI context should improve our ability to decode motor intent

  15. Determine Optimal Stimulus Amplitude for Using Vestibular Stochastic Stimulation to Improve Balance Function

    NASA Technical Reports Server (NTRS)

    Goel, R.; Kofman, I.; DeDios, Y. E.; Jeevarajan, J.; Stepanyan, V.; Nair, M.; Congdon, S.; Fregia, M.; Cohen, H.; Bloomberg, J.J.; Mulavara, A.P.

    2015-01-01

    Sensorimotor changes such as postural and gait instabilities can affect the functional performance of astronauts when they transition across different gravity environments. We are developing a method, based on stochastic resonance (SR), to enhance information transfer by applying non-zero levels of external noise on the vestibular system (vestibular stochastic resonance, VSR). Our previous work has shown the advantageous effects of VSR in a balance task of standing on an unstable surface [1]. This technique to improve detection of vestibular signals uses a stimulus delivery system that provides imperceptibly low levels of white noise-based binaural bipolar electrical stimulation of the vestibular system. The goal of this project is to determine optimal levels of stimulation for SR applications by using a defined vestibular threshold of motion detection. A series of experiments were carried out to determine a robust paradigm to identify a vestibular threshold that can then be used to recommend optimal stimulation levels for sensorimotor adaptability (SA) training applications customized to each crewmember. The amplitude of stimulation to be used in the VSR application has varied across studies in the literature such as 60% of nociceptive stimulus thresholds [2]. We compared subjects' perceptual threshold with that obtained from two measures of body sway. Each test session was 463s long and consisted of several 15s long sinusoidal stimuli, at different current amplitudes (0-2 mA), interspersed with 20-20.5s periods of no stimulation. Subjects sat on a chair with their eyes closed and had to report their perception of motion through a joystick. A force plate underneath the chair recorded medio-lateral shear forces and roll moments. Comparison of threshold of motion detection obtained from joystick data versus body sway suggests that perceptual thresholds were significantly lower. In the balance task, subjects stood on an unstable surface and had to maintain balance

  16. Optimal Stimulus Amplitude for Vestibular Stochastic Stimulation to Improve Sensorimotor Function

    NASA Technical Reports Server (NTRS)

    Goel, R.; Kofman, I.; DeDios, Y. E.; Jeevarajan, J.; Stepanyan, V.; Nair, M.; Congdon, S.; Fregia, M.; Cohen, H.; Bloomberg, J. J.; Mulavara, A. P.

    2014-01-01

    Sensorimotor changes such as postural and gait instabilities can affect the functional performance of astronauts when they transition across different gravity environments. We are developing a method, based on stochastic resonance (SR), to enhance information transfer by applying non-zero levels of external noise on the vestibular system (vestibular stochastic resonance, VSR). Our previous work has shown the advantageous effects of VSR in a balance task of standing on an unstable surface. This technique to improve detection of vestibular signals uses a stimulus delivery system that is wearable or portable and provides imperceptibly low levels of white noise-based binaural bipolar electrical stimulation of the vestibular system. The goal of this project is to determine optimal levels of stimulation for SR applications by using a defined vestibular threshold of motion detection. A series of experiments were carried out to determine a robust paradigm to identify a vestibular threshold that can then be used to recommend optimal stimulation levels for SR training applications customized to each crewmember. Customizing stimulus intensity can maximize treatment effects. The amplitude of stimulation to be used in the VSR application has varied across studies in the literature such as 60% of nociceptive stimulus thresholds. We compared subjects' perceptual threshold with that obtained from two measures of body sway. Each test session was 463s long and consisted of several 15s sinusoidal stimuli, at different current amplitudes (0-2 mA), interspersed with 20-20.5s periods of no stimulation. Subjects sat on a chair with their eyes closed and had to report their perception of motion through a joystick. A force plate underneath the chair recorded medio-lateral shear forces and roll moments. First we determined the percent time during stimulation periods for which perception of motion (activity above a pre-defined threshold) was reported using the joystick, and body sway (two

  17. Optimizing elicitation and seed priming to enrich broccoli and radish sprouts in glucosinolates.

    PubMed

    Baenas, Nieves; Villaño, Debora; García-Viguera, Cristina; Moreno, Diego A

    2016-08-01

    Elicitation is a cheaper and socially acceptable tool for improving plant food functionality. Our objective was to optimize the treatment doses of the elicitors: methyl jasmonate (MeJA), jasmonic acid (JA) and DL-methionine (MET), in order to find a successful and feasible treatment to produce broccoli and radish sprouts with enhanced levels of health-promoting glucosinolates. Also a priming of seeds as a novel strategy to trigger the glucosinolates content was carried out with water (control), MeJA (250μM), JA (250μM) and MET (10mM) before the elicitor exogenous treatment. The results showed that almost all treatments could enhance effectively the total glucosinolates content in the sprouts, achieving the most significant increases from 34% to 100% of increase in broccoli and from 45% to 118% of increase in radish sprouts after MeJA priming and treatments. Consequently, our work demonstrates the feasibility of using elicitors, such as plant stress hormones, by priming and exogenously, as a way of increase the phytochemical profile of these sprouts to enhance their consumption in the diet. PMID:26988507

  18. Optimizing elicitation and seed priming to enrich broccoli and radish sprouts in glucosinolates.

    PubMed

    Baenas, Nieves; Villaño, Debora; García-Viguera, Cristina; Moreno, Diego A

    2016-08-01

    Elicitation is a cheaper and socially acceptable tool for improving plant food functionality. Our objective was to optimize the treatment doses of the elicitors: methyl jasmonate (MeJA), jasmonic acid (JA) and DL-methionine (MET), in order to find a successful and feasible treatment to produce broccoli and radish sprouts with enhanced levels of health-promoting glucosinolates. Also a priming of seeds as a novel strategy to trigger the glucosinolates content was carried out with water (control), MeJA (250μM), JA (250μM) and MET (10mM) before the elicitor exogenous treatment. The results showed that almost all treatments could enhance effectively the total glucosinolates content in the sprouts, achieving the most significant increases from 34% to 100% of increase in broccoli and from 45% to 118% of increase in radish sprouts after MeJA priming and treatments. Consequently, our work demonstrates the feasibility of using elicitors, such as plant stress hormones, by priming and exogenously, as a way of increase the phytochemical profile of these sprouts to enhance their consumption in the diet.

  19. Vestibular Stochastic Resonance as a Method to Improve Balance Function: Optimization of Stimulus Characteristics

    NASA Technical Reports Server (NTRS)

    Mulavara, Ajitkumar; Fiedler, Matthew; Kofman, Igor; Peters, Brian; Wood, Scott; Serrador, Jorge; Cohen, Helen; Reschke, Millard; Bloomberg, Jacob

    2010-01-01

    Stochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant sensory signals. Application of imperceptible SR noise coupled with sensory input through the proprioceptive, visual, or vestibular sensory systems has been shown to improve motor function. Specifically, studies have shown that that vestibular electrical stimulation by imperceptible stochastic noise, when applied to normal young and elderly subjects, significantly improved their ocular stabilization reflexes in response to whole-body tilt as well as balance performance during postural disturbances. The goal of this study was to optimize the characteristics of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standardized balance task of standing on a block of 10 cm thick medium density foam with their eyes closed for a total of 40 seconds. Stochastic electrical stimulation was applied to the vestibular system through electrodes placed over the mastoid process behind the ears during the last 20 seconds of the test period. A custom built constant current stimulator with subject isolation delivered the stimulus. Stimulation signals were generated with frequencies in the bandwidth of 1-2 Hz and 0.01-30 Hz. Amplitude of the signals were varied in the range of 0- +/-700 micro amperes with the RMS of the signal increased by 30 micro amperes for each 100 micro amperes increase in the current range. Balance performance was measured using a force plate under the foam block and inertial motion sensors placed on the torso and head segments. Preliminary results indicate that balance performance is improved in the range of 10-25% compared to no stimulation conditions. Subjects improved their performance consistently across the blocks of stimulation. Further the signal amplitude at which the performance was maximized was different in the two frequency ranges. Optimization of the frequency and

  20. Towards an Optimization of Stimulus Parameters for Brain-Computer Interfaces Based on Steady State Visual Evoked Potentials

    PubMed Central

    Radzikowska, Zofia; Milanowski, Piotr; Kuś, Rafał; Suffczyński, Piotr; Michalska, Magdalena; Łabęcki, Maciej; Zwoliński, Piotr; Durka, Piotr

    2014-01-01

    Efforts to construct an effective brain-computer interface (BCI) system based on Steady State Visual Evoked Potentials (SSVEP) commonly focus on sophisticated mathematical methods for data analysis. The role of different stimulus features in evoking strong SSVEP is less often considered and the knowledge on the optimal stimulus properties is still fragmentary. The goal of this study was to provide insight into the influence of stimulus characteristics on the magnitude of SSVEP response. Five stimuli parameters were tested: size, distance, colour, shape, and presence of a fixation point in the middle of each flickering field. The stimuli were presented on four squares on LCD screen, with each square highlighted by LEDs flickering with different frequencies. Brighter colours and larger dimensions of flickering fields resulted in a significantly stronger SSVEP response. The distance between stimulation fields and the presence or absence of the fixation point had no significant effect on the response. Contrary to a popular belief, these results suggest that absence of the fixation point does not reduce the magnitude of SSVEP response. However, some parameters of the stimuli such as colour and the size of the flickering field play an important role in evoking SSVEP response, which indicates that stimuli rendering is an important factor in building effective SSVEP based BCI systems. PMID:25398134

  1. Towards an optimization of stimulus parameters for brain-computer interfaces based on steady state visual evoked potentials.

    PubMed

    Duszyk, Anna; Bierzyńska, Maria; Radzikowska, Zofia; Milanowski, Piotr; Kuś, Rafał; Suffczyński, Piotr; Michalska, Magdalena; Łabęcki, Maciej; Zwoliński, Piotr; Durka, Piotr

    2014-01-01

    Efforts to construct an effective brain-computer interface (BCI) system based on Steady State Visual Evoked Potentials (SSVEP) commonly focus on sophisticated mathematical methods for data analysis. The role of different stimulus features in evoking strong SSVEP is less often considered and the knowledge on the optimal stimulus properties is still fragmentary. The goal of this study was to provide insight into the influence of stimulus characteristics on the magnitude of SSVEP response. Five stimuli parameters were tested: size, distance, colour, shape, and presence of a fixation point in the middle of each flickering field. The stimuli were presented on four squares on LCD screen, with each square highlighted by LEDs flickering with different frequencies. Brighter colours and larger dimensions of flickering fields resulted in a significantly stronger SSVEP response. The distance between stimulation fields and the presence or absence of the fixation point had no significant effect on the response. Contrary to a popular belief, these results suggest that absence of the fixation point does not reduce the magnitude of SSVEP response. However, some parameters of the stimuli such as colour and the size of the flickering field play an important role in evoking SSVEP response, which indicates that stimuli rendering is an important factor in building effective SSVEP based BCI systems.

  2. Stimulus control: Part I

    PubMed Central

    Dinsmoor, James A.

    1995-01-01

    In his effort to distinguish operant from respondent conditioning, Skinner stressed the lack of an eliciting stimulus and rejected the prevailing stereotype of Pavlovian “stimulus—response” psychology. But control by antecedent stimuli, whether classified as conditional or discriminative, is ubiquitous in the natural setting. With both respondent and operant behavior, symmetrical gradients of generalization along unrelated dimensions may be obtained following differential reinforcement in the presence and the absence of the stimulus. The slopes of these gradients serve as measures of stimulus control, and they can be steepened without applying differential reinforcement to any two points along the test dimension. Increases and decreases in stimulus control occur under the same conditions as those leading to increases and decreases in observing responses, indicating that it is the increasing frequency and duration of observation (and perhaps also of attention) that produces the separation in performances during discrimination learning. PMID:22478204

  3. A stimulus-dependent spike threshold is an optimal neural coder

    PubMed Central

    Jones, Douglas L.; Johnson, Erik C.; Ratnam, Rama

    2015-01-01

    A neural code based on sequences of spikes can consume a significant portion of the brain's energy budget. Thus, energy considerations would dictate that spiking activity be kept as low as possible. However, a high spike-rate improves the coding and representation of signals in spike trains, particularly in sensory systems. These are competing demands, and selective pressure has presumably worked to optimize coding by apportioning a minimum number of spikes so as to maximize coding fidelity. The mechanisms by which a neuron generates spikes while maintaining a fidelity criterion are not known. Here, we show that a signal-dependent neural threshold, similar to a dynamic or adapting threshold, optimizes the trade-off between spike generation (encoding) and fidelity (decoding). The threshold mimics a post-synaptic membrane (a low-pass filter) and serves as an internal decoder. Further, it sets the average firing rate (the energy constraint). The decoding process provides an internal copy of the coding error to the spike-generator which emits a spike when the error equals or exceeds a spike threshold. When optimized, the trade-off leads to a deterministic spike firing-rule that generates optimally timed spikes so as to maximize fidelity. The optimal coder is derived in closed-form in the limit of high spike-rates, when the signal can be approximated as a piece-wise constant signal. The predicted spike-times are close to those obtained experimentally in the primary electrosensory afferent neurons of weakly electric fish (Apteronotus leptorhynchus) and pyramidal neurons from the somatosensory cortex of the rat. We suggest that KCNQ/Kv7 channels (underlying the M-current) are good candidates for the decoder. They are widely coupled to metabolic processes and do not inactivate. We conclude that the neural threshold is optimized to generate an energy-efficient and high-fidelity neural code. PMID:26082710

  4. Estimation of an Optimal Stimulus Amplitude for Using Vestibular Stochastic Stimulation to Improve Balance Function

    NASA Technical Reports Server (NTRS)

    Goel, R.; Kofman, I.; DeDios, Y. E.; Jeevarajan, J.; Stepanyan, V.; Nair, M.; Congdon, S.; Fregia, M.; Peters, B.; Cohen, H.; Wood, S.; Bloomberg, J. J.; Mulavara, A. P.

    2015-01-01

    Sensorimotor changes such as postural and gait instabilities can affect the functional performance of astronauts when they transition across different gravity environments. We are developing a method, based on stochastic resonance (SR), to enhance information transfer by applying non-zero levels of external noise on the vestibular system (vestibular stochastic resonance, VSR). The goal of this project was to determine optimal levels of stimulation for SR applications by using a defined vestibular threshold of motion detection.

  5. Sub-Optimal Choice in Pigeons Does Not Depend on Avoidance of the Stimulus Associated with the Absence of Reinforcement

    ERIC Educational Resources Information Center

    Stagner, Jessica P.; Laude, Jennifer R.; Zentall, Thomas R.

    2011-01-01

    When pigeons are given a choice between two alternatives, one leading to a stimulus 20% of the time that always signals reinforcement (S+) or another stimulus 80% of the time that signals no reinforcement (S-), and the other alternative leading to one of two stimuli each signaling reinforcement 50% of the time, they show a strong preference for…

  6. Optimization of the culture medium composition to improve the production of hyoscyamine in elicited Datura stramonium L. hairy roots using the Response Surface Methodology (RSM).

    PubMed

    Ryad, Amdoun; Lakhdar, Khelifi; Majda, Khelifi-Slaoui; Samia, Amroune; Mark, Asch; Corinne, Assaf-Ducrocq; Eric, Gontier

    2010-11-18

    Traditionally, optimization in biological analyses has been carried out by monitoring the influence of one factor at a time; this technique is called one-variable-at-a-time. The disadvantage of this technique is that it does not include any interactive effects among the variables studied and requires a large number of experiments. Therefore, in recent years, the Response Surface Methodology (RSM) has become the most popular optimization method. It is an effective mathematical and statistical technique which has been widely used in optimization studies with minimal experimental trials where interactive factors may be involved. This present study follows on from our previous work, where RSM was used to optimize the B5 medium composition in [NO(3-)], [Ca(2+)] and sucrose to attain the best production of hyoscyamine (HS) from the hairy roots (HRs) of Datura stramonium elicited by Jasmonic Acid (JA). The present paper focuses on the use of the RSM in biological studies, such as plant material, to establish a predictive model with the planning of experiments, analysis of the model, diagnostics and adjustment for the accuracy of the model. With the RSM, only 20 experiments were necessary to determine optimal concentrations. The model could be employed to carry out interpolations and predict the response to elicitation. Applying this model, the optimization of the HS level was 212.7% for the elicited HRs of Datura stramonium, cultured in B5-OP medium (optimized), in comparison with elicited HRs cultured in B5 medium (control). The optimal concentrations, under experimental conditions, were determined to be: 79.1 mM [NO(3-)], 11.4 mM [Ca(2+)] and 42.9 mg/L of sucrose.

  7. Stimulus Response

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2010-01-01

    Stimulus funds unquestionably have helped many schools keep going through tough times, but for many institutions, the tough times aren't going away anytime soon. That is why, a little more than a year after Congress passed the American Recovery and Reinvestment Act and began allocating billions of dollars in aid across the nation, the so-called…

  8. Non-linear stimulus-response behavior of the human stance control system is predicted by optimization of a system with sensory and motor noise.

    PubMed

    van der Kooij, Herman; Peterka, Robert J

    2011-06-01

    We developed a theory of human stance control that predicted (1) how subjects re-weight their utilization of proprioceptive and graviceptive orientation information in experiments where eyes closed stance was perturbed by surface-tilt stimuli with different amplitudes, (2) the experimentally observed increase in body sway variability (i.e. the "remnant" body sway that could not be attributed to the stimulus) with increasing surface-tilt amplitude, (3) neural controller feedback gains that determine the amount of corrective torque generated in relation to sensory cues signaling body orientation, and (4) the magnitude and structure of spontaneous body sway. Responses to surface-tilt perturbations with different amplitudes were interpreted using a feedback control model to determine control parameters and changes in these parameters with stimulus amplitude. Different combinations of internal sensory and/or motor noise sources were added to the model to identify the properties of noise sources that were able to account for the experimental remnant sway characteristics. Various behavioral criteria were investigated to determine if optimization of these criteria could predict the identified model parameters and amplitude-dependent parameter changes. Robust findings were that remnant sway characteristics were best predicted by models that included both sensory and motor noise, the graviceptive noise magnitude was about ten times larger than the proprioceptive noise, and noise sources with signal-dependent properties provided better explanations of remnant sway. Overall results indicate that humans dynamically weight sensory system contributions to stance control and tune their corrective responses to minimize the energetic effects of sensory noise and external stimuli.

  9. Partially supervised P300 speller adaptation for eventual stimulus timing optimization: target confidence is superior to error-related potential score as an uncertain label

    NASA Astrophysics Data System (ADS)

    Zeyl, Timothy; Yin, Erwei; Keightley, Michelle; Chau, Tom

    2016-04-01

    Objective. Error-related potentials (ErrPs) have the potential to guide classifier adaptation in BCI spellers, for addressing non-stationary performance as well as for online optimization of system parameters, by providing imperfect or partial labels. However, the usefulness of ErrP-based labels for BCI adaptation has not been established in comparison to other partially supervised methods. Our objective is to make this comparison by retraining a two-step P300 speller on a subset of confident online trials using naïve labels taken from speller output, where confidence is determined either by (i) ErrP scores, (ii) posterior target scores derived from the P300 potential, or (iii) a hybrid of these scores. We further wish to evaluate the ability of partially supervised adaptation and retraining methods to adjust to a new stimulus-onset asynchrony (SOA), a necessary step towards online SOA optimization. Approach. Eleven consenting able-bodied adults attended three online spelling sessions on separate days with feedback in which SOAs were set at 160 ms (sessions 1 and 2) and 80 ms (session 3). A post hoc offline analysis and a simulated online analysis were performed on sessions two and three to compare multiple adaptation methods. Area under the curve (AUC) and symbols spelled per minute (SPM) were the primary outcome measures. Main results. Retraining using supervised labels confirmed improvements of 0.9 percentage points (session 2, p < 0.01) and 1.9 percentage points (session 3, p < 0.05) in AUC using same-day training data over using data from a previous day, which supports classifier adaptation in general. Significance. Using posterior target score alone as a confidence measure resulted in the highest SPM of the partially supervised methods, indicating that ErrPs are not necessary to boost the performance of partially supervised adaptive classification. Partial supervision significantly improved SPM at a novel SOA, showing promise for eventual online SOA

  10. Stimulus Reporting Advances

    ERIC Educational Resources Information Center

    McNeil, Michele

    2009-01-01

    Faced with their first reporting deadlines for economic-stimulus aid to education, school districts are toiling over how every stimulus penny has been spent so far and how many jobs have been saved--numbers that will be scrutinized not just by the public, but by government auditors as well. The American Recovery and Reinvestment Act, passed by…

  11. Stimulus-parity synaesthesia versus stimulus-dichotomy synaesthesia: Odd, even or something else?

    PubMed Central

    White, Rebekah C.; Plassart, Anna

    2015-01-01

    In stimulus-parity synaesthesia, a range of stimuli—for example, letters, numbers, weekdays, months, and colours (the inducers)—elicit an automatic feeling of oddness or evenness (the concurrent). This phenomenon was first described by Théodore Flournoy in 1893, and has only recently been “rediscovered.” Here, we describe an individual who experiences a comparable phenomenon, but uses the labels negative and positive rather than odd and even. Stimulus-parity synaesthesia may be broader than first supposed, and it is important that assessments are sensitive to this breadth. PMID:26034572

  12. Ludic Elicitation: Using Games for Knowledge Elicitation

    ERIC Educational Resources Information Center

    Cao, Yan

    2014-01-01

    Knowledge elicitation from human beings is important for many fields, such as decision support systems, risk communication, and customer preference studying. Traditional approaches include observations, questionnaires, structured and semi-structured interviews, and group discussions. Many publications have been studying different techniques for a…

  13. Asymmetrical Stimulus Generalization following Differential Fear Conditioning

    PubMed Central

    Bang, Sun Jung; Allen, Timothy A.; Jones, Lauren K.; Boguszewski, Pawel; Brown, Thomas H.

    2008-01-01

    Rodent ultrasonic vocalizations (USVs) are ethologically critical social signals. Rats emit 22 kHz USVs and 50 kHz USVs, respectively, in conjunction with negative and positive affective states. Little is known about what controls emotional reactivity to these social signals. Using male Sprague-Dawley rats, we examined unconditional and conditional freezing behavior in response to the following auditory stimuli: three 22 kHz USVs, a discontinuous tone whose frequency and on-off pattern matched one of the USVs, a continuous tone with the same or lower frequencies, a 4 kHz discontinuous tone with an on-off pattern matched to one of the USVs, and a 50 kHz USV. There were no differences among these stimuli in terms of the unconditional elicitation of freezing behavior. Thus, the stimuli were equally neutral before conditioning. During differential fear conditioning, one of these stimuli (the CS+) always co-terminated with a footshock unconditional stimulus (US) and another stimulus (the CS−) was explicitly unpaired with the US. There were no significant differences among these cues in CS+-elicited freezing behavior. Thus, the stimuli were equally salient or effective as cues in supporting fear conditioning. When the CS+ was a 22 kHz USV or a similar stimulus, rats discriminated based on the principal frequency and/or the temporal pattern of the stimulus. However, when these same stimuli served as the CS−, discrimination failed due to generalization from the CS+. Thus, the stimuli differed markedly in the specificity of conditioning. This strikingly asymmetrical stimulus generalization is a novel bias in discrimination. PMID:18434217

  14. Patients’ values and preferences of the expected efficacy of hip arthroscopy for osteoarthritis: a protocol for a multinational structured interview-based study combined with a randomised survey on the optimal amount of information to elicit preferences

    PubMed Central

    Zhang, Yuqing; Tikkinen, Kari A O; Agoritsas, Thomas; Ayeni, Olufemi R; Alexander, Paul; Imam, Maha; Yoo, Daniel; Tsalatsanis, Athanasios; Djulbegovic, Benjamin; Thabane, Lehana; Schünemann, Holger; Guyatt, Gordon H

    2014-01-01

    Introduction Symptomatic hip osteoarthritis (OA) is a disabling condition with up to a 25% cumulative lifetime risk. Total hip arthroplasty (THA) is effective in relieving patients’ symptoms and improving function. It is, however, associated with substantial risk of complications, pain and major functional limitation before patients can return to full function. In contrast, hip arthroscopy (HA) is less invasive and can postpone THA. However, there is no evidence regarding the delay in the need for THA that patients would find acceptable to undergoing HA. Knowing patients’ values and preferences (VP) on this expected delay is critical when making recommendations regarding the advisability of HA. Furthermore, little is known on the optimal amount of information regarding interventions and outcomes needed to present in order to optimally elicit patients’ VP. Methods and analysis We will perform a multinational, structured interview-based survey of preference in delay time for THA among patients with non-advanced OA who failed to respond to conservative therapy. We will combine these interviews with a randomised trial addressing the optimal amount of information regarding the interventions and outcomes required to elicit preferences. Eligible patients will be randomly assigned (1 : 1) to either a short or a long format of health scenarios of THA and HA. We will determine each patient's VP using a trade-off and anticipated regret exercises. Our primary outcomes for the combined surveys will be: (1) the minimal delay time in the need for THA surgery that patients would find acceptable to undertaking HA, (2) patients’ satisfaction with the amount of information provided in the health scenarios used to elicit their VPs. Ethics and dissemination The protocol has been approved by the Hamilton Integrated Research Ethics Board (HIREB13-506). We will disseminate our study findings through peer-reviewed publications and conference presentations, and make them

  15. Stimulus responsive nanoparticles

    NASA Technical Reports Server (NTRS)

    Cairns, Darren Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2013-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  16. Stimulus Responsive Nanoparticles

    NASA Technical Reports Server (NTRS)

    Cairns, Darran Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2015-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  17. Alteration of neural action potential patterns by axonal stimulation: the importance of stimulus location

    NASA Astrophysics Data System (ADS)

    Crago, Patrick E.; Makowski, Nathaniel S.

    2014-10-01

    Objective. Stimulation of peripheral nerves is often superimposed on ongoing motor and sensory activity in the same axons, without a quantitative model of the net action potential train at the axon endpoint. Approach. We develop a model of action potential patterns elicited by superimposing constant frequency axonal stimulation on the action potentials arriving from a physiologically activated neural source. The model includes interactions due to collision block, resetting of the neural impulse generator, and the refractory period of the axon at the point of stimulation. Main results. Both the mean endpoint firing rate and the probability distribution of the action potential firing periods depend strongly on the relative firing rates of the two sources and the intersite conduction time between them. When the stimulus rate exceeds the neural rate, neural action potentials do not reach the endpoint and the rate of endpoint action potentials is the same as the stimulus rate, regardless of the intersite conduction time. However, when the stimulus rate is less than the neural rate, and the intersite conduction time is short, the two rates partially sum. Increases in stimulus rate produce non-monotonic increases in endpoint rate and continuously increasing block of neurally generated action potentials. Rate summation is reduced and more neural action potentials are blocked as the intersite conduction time increases. At long intersite conduction times, the endpoint rate simplifies to being the maximum of either the neural or the stimulus rate. Significance. This study highlights the potential of increasing the endpoint action potential rate and preserving neural information transmission by low rate stimulation with short intersite conduction times. Intersite conduction times can be decreased with proximal stimulation sites for muscles and distal stimulation sites for sensory endings. The model provides a basis for optimizing experiments and designing neuroprosthetic

  18. Alteration of neural action potential patterns by axonal stimulation: the importance of stimulus location

    PubMed Central

    Crago, Patrick E; Makowski, Nathan S

    2014-01-01

    Objective Stimulation of peripheral nerves is often superimposed on ongoing motor and sensory activity in the same axons, without a quantitative model of the net action potential train at the axon endpoint. Approach We develop a model of action potential patterns elicited by superimposing constant frequency axonal stimulation on the action potentials arriving from a physiologically activated neural source. The model includes interactions due to collision block, resetting of the neural impulse generator, and the refractory period of the axon at the point of stimulation. Main Results Both the mean endpoint firing rate and the probability distribution of the action potential firing periods depend strongly on the relative firing rates of the two sources and the intersite conduction time between them. When the stimulus rate exceeds the neural rate, neural action potentials do not reach the endpoint and the rate of endpoint action potentials is the same as the stimulus rate, regardless of the intersite conduction time. However, when the stimulus rate is less than the neural rate, and the intersite conduction time is short, the two rates partially sum. Increases in stimulus rate produce non-monotonic increases in endpoint rate and continuously increasing block of neurally generated action potentials. Rate summation is reduced and more neural action potentials are blocked as the intersite conduction time increases.. At long intersite conduction times, the endpoint rate simplifies to being the maximum of either the neural or the stimulus rate. Significance This study highlights the potential of increasing the endpoint action potential rate and preserving neural information transmission by low rate stimulation with short intersite conduction times. Intersite conduction times can be decreased with proximal stimulation sites for muscles and distal stimulation sites for sensory endings. The model provides a basis for optimizing experiments and designing neuroprosthetic

  19. Adaptation to second order stimulus features by electrosensory neurons causes ambiguity

    PubMed Central

    Zhang, Zhubo D.; Chacron, Maurice J.

    2016-01-01

    Understanding the coding strategies used to process sensory input remains a central problem in neuroscience. Growing evidence suggests that sensory systems process natural stimuli efficiently by ensuring a close match between neural tuning and stimulus statistics through adaptation. However, adaptation causes ambiguity as the same response can be elicited by different stimuli. The mechanisms by which the brain resolves ambiguity remain poorly understood. Here we investigated adaptation in electrosensory pyramidal neurons within different parallel maps in the weakly electric fish Apteronotus leptorhynchus. In response to step increases in stimulus variance, we found that pyramidal neurons within the lateral segment (LS) displayed strong scale invariant adaptation whereas those within the centromedial segment (CMS) instead displayed weaker degrees of scale invariant adaptation. Signal detection analysis revealed that strong adaptation in LS neurons significantly reduced stimulus discriminability. In contrast, weaker adaptation displayed by CMS neurons led to significantly lesser impairment of discriminability. Thus, while LS neurons display adaptation that is matched to natural scene statistics, thereby optimizing information transmission, CMS neurons instead display weaker adaptation and would instead provide information about the context in which these statistics occur. We propose that such a scheme is necessary for decoding by higher brain structures. PMID:27349635

  20. Interests and Stimulus Seeking

    ERIC Educational Resources Information Center

    Kish, George B.; Donnenwerth, Gregory V.

    1969-01-01

    Examines relationships between Sensation-Seeking Scale (SSS) and vocational interests measured by the Kuder and Strong Vocational Interest Blank, among alcoholics and undergraduates. Results support construct validity of the SSS and provide further evidence of modes of expression of stimulus-seeking needs in personality. (Author/CJ)

  1. Using independent component analysis to remove artifacts in visual cortex responses elicited by electrical stimulation of the optic nerve

    NASA Astrophysics Data System (ADS)

    Lu, Yiliang; Cao, Pengjia; Sun, Jingjing; Wang, Jing; Li, Liming; Ren, Qiushi; Chen, Yao; Chai, Xinyu

    2012-04-01

    In visual prosthesis research, electrically evoked potentials (EEPs) can be elicited by one or more biphasic current pulses delivered to the optic nerve (ON) through penetrating electrodes. Multi-channel EEPs recorded from the visual cortex usually contain large stimulus artifacts caused by instantaneous electrotonic current spread through the brain tissue. These stimulus artifacts contaminate the EEP waveform and often make subsequent analysis of the underlying neural responses difficult. This is particularly serious when investigating EEPs in response to electrical stimulation with long duration and multi-pulses. We applied independent component analysis (ICA) to remove these electrical stimulation-induced artifacts during the development of a visual prosthesis. Multi-channel signals were recorded from visual cortices of five rabbits in response to ON electrical stimulation with various stimulus parameters. ON action potentials were then blocked by lidocaine in order to acquire cortical potentials only including stimulus artifacts. Correlation analysis of reconstructed artifacts by ICA and artifacts recorded after blocking the ON indicates successful removal of artifacts from electrical stimulation by the ICA method. This technique has potential applications in studies designed to optimize the electrical stimulation parameters used by visual prostheses.

  2. Eliciting Sound Memories.

    PubMed

    Harris, Anna

    2015-11-01

    Sensory experiences are often considered triggers of memory, most famously a little French cake dipped in lime blossom tea. Sense memory can also be evoked in public history research through techniques of elicitation. In this article I reflect on different social science methods for eliciting sound memories such as the use of sonic prompts, emplaced interviewing, and sound walks. I include examples from my research on medical listening. The article considers the relevance of this work for the conduct of oral histories, arguing that such methods "break the frame," allowing room for collaborative research connections and insights into the otherwise unarticulatable.

  3. Disentangling sequential effects of stimulus- and response-related conflict and stimulus-response repetition using brain potentials.

    PubMed

    Wendt, Mike; Heldmann, Marcus; Münte, Thomas F; Kluwe, Rainer H

    2007-07-01

    Conflict monitoring theory holds that detection of conflicts in information processing by the anterior cingulate cortex (ACC) results in processing adaptation that minimizes subsequent conflict. Applying an Eriksen f lanker task with four stimuli mapped onto two responses, we investigated whether such modulation occurs only after response-related or also after stimulus-related conflict, focusing on the N2 component of the event-related potential. Contrasting with previous findings, both stimulus- and response-related conflict elicited enhancement of the N2, suggesting that the ACC is sensitive to conflict at both the stimulus and the response level. However, neither type of conflict resulted in reduced conflict effects on the following trial when stimulus-response (S-R) sequence effects were controlled by excluding identical S-R repetition trials. Identical S-R repetitions were associated with facilitated processing, thus demonstrating that inclusion of these trials in the analysis may mimic results predicted by the conflict adaptation hypothesis.

  4. Contextual task difficulty modulates stimulus discrimination: electrophysiological evidence for interaction between sensory and executive processes.

    PubMed

    Fedota, John R; McDonald, Craig G; Roberts, Daniel M; Parasuraman, Raja

    2012-10-01

    The occipital-temporal N1 component of the event-related potential (ERP) has previously been shown to index a stimulus discrimination process. However, the N1 has not consistently been shown to be sensitive to the difficulty of stimulus discrimination. Here, we manipulated the difficulty of stimulus discrimination by modulating the similarity between serially presented targets and nontargets. The same target stimulus was employed in both easy and difficult discrimination contexts, and these physically identical target stimuli elicited a larger N1 and smaller P3b in the difficult task context. Moreover, when targets were incorrectly categorized, N1 amplitude was diminished and a P3b was not elicited. These findings provide evidence that the N1 component reflects a sensory discrimination process that is modulated by executive control, and that this component can index discrimination errors when stimulus discrimination is difficult.

  5. Contextual task difficulty modulates stimulus discrimination: Electrophysiological evidence for interaction between sensory and executive processes

    PubMed Central

    Fedota, John R.; McDonald, Craig G.; Roberts, Daniel M.; Parasuraman, Raja

    2012-01-01

    The occipital-temporal N1 component of the event-related potential (ERP) has previously been shown to index a stimulus discrimination process. However, the N1 has not consistently been shown to be sensitive to the difficulty of stimulus discrimination. Here we manipulated the difficulty of stimulus discrimination by modulating the similarity between serially presented targets and non-targets. The same target stimulus was employed in both easy and difficult discrimination contexts, and these physically identical target stimuli elicited a larger N1 and smaller P3b in the difficult task context. Moreover, when targets were incorrectly categorized, N1 amplitude was diminished and a P3b was not elicited. These findings provide evidence that the N1 component reflects a sensory discrimination process that is modulated by executive control, and that this component can index discrimination errors when stimulus discrimination is difficult. PMID:22906001

  6. Understanding smell--the olfactory stimulus problem.

    PubMed

    Auffarth, Benjamin

    2013-09-01

    The main problem with sensory processing is the difficulty in relating sensory input to physiological responses and perception. This is especially problematic at higher levels of processing, where complex cues elicit highly specific responses. In olfaction, this relationship is particularly obfuscated by the difficulty of characterizing stimulus statistics and perception. The core questions in olfaction are hence the so-called stimulus problem, which refers to the understanding of the stimulus, and the structure-activity and structure-odor relationships, which refer to the molecular basis of smell. It is widely accepted that the recognition of odorants by receptors is governed by the detection of physico-chemical properties and that the physical space is highly complex. Not surprisingly, ideas differ about how odor stimuli should be classified and about the very nature of information that the brain extracts from odors. Even though there are many measures for smell, there is none that accurately describes all aspects of it. Here, we summarize recent developments in the understanding of olfaction. We argue that an approach to olfactory function where information processing is emphasized could contribute to a high degree to our understanding of smell as a perceptual phenomenon emerging from neural computations. Further, we argue that combined analysis of the stimulus, biology, physiology, and behavior and perception can provide new insights into olfactory function. We hope that the reader can use this review as a competent guide and overview of research activities in olfactory physiology, psychophysics, computation, and psychology. We propose avenues for research, particularly in the systematic characterization of receptive fields and of perception.

  7. Biologically inspired robots elicit a robust fear response in zebrafish

    NASA Astrophysics Data System (ADS)

    Ladu, Fabrizio; Bartolini, Tiziana; Panitz, Sarah G.; Butail, Sachit; Macrı, Simone; Porfiri, Maurizio

    2015-03-01

    We investigate the behavioral response of zebrafish to three fear-evoking stimuli. In a binary choice test, zebrafish are exposed to a live allopatric predator, a biologically-inspired robot, and a computer-animated image of the live predator. A target tracking algorithm is developed to score zebrafish behavior. Unlike computer-animated images, the robotic and live predator elicit a robust avoidance response. Importantly, the robotic stimulus elicits more consistent inter-individual responses than the live predator. Results from this effort are expected to aid in hypothesis-driven studies on zebrafish fear response, by offering a valuable approach to maximize data-throughput and minimize animal subjects.

  8. Punishment of elicited aggression.

    PubMed

    Azrin, N H

    1970-07-01

    Aversive shocks are known to produce aggression when the shocks are not dependent on behavior and to suppress behavior when the shocks are arranged as a dependent punisher. These two processes were studied by presenting non-dependent shock to monkeys at regular intervals, thereby producing biting attacks on a pneumatic tube. Immediate shock punishment was stimultaneously delivered for each biting attack. The attacks were found to decrease as a function of increasing punishment intensity. These results show that aggression is eliminated by direct punishment of the aggression even when the stimulus that is used as a punisher otherwise causes the aggression. PMID:4988590

  9. Novelty is not enough: laser-evoked potentials are determined by stimulus saliency, not absolute novelty.

    PubMed

    Ronga, I; Valentini, E; Mouraux, A; Iannetti, G D

    2013-02-01

    Event-related potentials (ERPs) elicited by transient nociceptive stimuli in humans are largely sensitive to bottom-up novelty induced, for example, by changes in stimulus attributes (e.g., modality or spatial location) within a stream of repeated stimuli. Here we aimed 1) to test the contribution of a selective change of the intensity of a repeated stimulus in determining the magnitude of nociceptive ERPs, and 2) to dissect the effect of this change of intensity in terms of "novelty" and "saliency" (an increase of stimulus intensity is more salient than a decrease of stimulus intensity). Nociceptive ERPs were elicited by trains of three consecutive laser stimuli (S1-S2-S3) delivered to the hand dorsum at a constant 1-s interstimulus interval. Three, equally spaced intensities were used: low (L), medium (M), and high (H). While the intensities of S1 and S2 were always identical (L, M, or H), the intensity of S3 was either identical (e.g., HHH) or different (e.g., MMH) from the intensity of S1 and S2. Introducing a selective change in stimulus intensity elicited significantly larger N1 and N2 waves of the S3-ERP but only when the change consisted in an increase in stimulus intensity. This observation indicates that nociceptive ERPs do not simply reflect processes involved in the detection of novelty but, instead, are mainly determined by stimulus saliency. PMID:23136349

  10. Variability of stimulus effect in the course of phallometric testing.

    PubMed

    Kolárský, A; Madlafousek, J

    1977-03-01

    To study the serial effect in phallometric experiments, several sexual stimuli (film scenes) were presented in different orders to 56 subjects in four groups. All stimuli were presented at a relatively constant basal level of penile volume after the subjects' engagement in a nonsexual cognitive task. Serial effects occurred. At the beginning of the session, the magnitude of penile response did not depend on the content of sexual stimuli, the second stimulus eliciting a higher effect than the first. The differential effect of stimuli occurred only when they were shown in the third or fourth position. Finally, it was demonstrated that the effect of the stimulus depends to some extent on the effect of the preceding stimulus.

  11. Reward positivity elicited by predictive cues.

    PubMed

    Holroyd, Clay B; Krigolson, Olav E; Lee, Seung

    2011-03-30

    A recent theory holds that a component of the human event-related brain potential called the reward positivity reflects a reward prediction error signal. We investigated this idea in gambling-like task in which, on each trial, a visual stimulus predicted a subsequent rewarding or nonrewarding outcome with 80% probability. Consistent with earlier results, we found that the reward positivity was larger to unexpected than to expected outcomes. In addition, we found that the predictive cues also elicited a reward positivity, as proposed by the theory. These results indicate that the reward positivity reflects the initial assessment of whether a trial will end in success or failure and the reappraisal of that information once the outcome actually occurs.

  12. Correlations among stimuli affect stimulus matching and stimulus liking.

    PubMed

    Pimenta, Dióghenes; Tonneau, François

    2016-09-01

    Human subjects were exposed to AB, AC stimulus pairs and then to matching-to-sample tests of stimulus equivalence (B-A, C-A, B-C, C-B) or to a task in which stimulus compounds (BA, CA, BC, CB) were rated for attractiveness. Matching-to-sample tests revealed emergent B-A, C-A, B-C, and C-B choices, replicating previous results in the literature. The mean proportion of correct, emergent choices increased as a function of exposure to the AB, AC pairs. On the rating task, the liking scores of all stimulus compounds also increased as a function of exposure to the AB, AC pairs. After limited exposure to these pairs, however, the liking scores of the BC and CB compounds were negative. These findings are discussed in relation to perceptual and associative perspectives on the behavioral effects of stimulus correlations.

  13. Correlations among stimuli affect stimulus matching and stimulus liking.

    PubMed

    Pimenta, Dióghenes; Tonneau, François

    2016-09-01

    Human subjects were exposed to AB, AC stimulus pairs and then to matching-to-sample tests of stimulus equivalence (B-A, C-A, B-C, C-B) or to a task in which stimulus compounds (BA, CA, BC, CB) were rated for attractiveness. Matching-to-sample tests revealed emergent B-A, C-A, B-C, and C-B choices, replicating previous results in the literature. The mean proportion of correct, emergent choices increased as a function of exposure to the AB, AC pairs. On the rating task, the liking scores of all stimulus compounds also increased as a function of exposure to the AB, AC pairs. After limited exposure to these pairs, however, the liking scores of the BC and CB compounds were negative. These findings are discussed in relation to perceptual and associative perspectives on the behavioral effects of stimulus correlations. PMID:27397574

  14. High voltage with little current as an unconditional stimulus for taste avoidance conditioning in Lymnaea stagnalis.

    PubMed

    Takigami, Satoshi; Sunada, Hiroshi; Lukowiak, Ken; Sakakibara, Manabu

    2013-10-25

    A new and better taste avoidance conditioning paradigm for Lymnaea has been developed that replaces the previously used tactile unconditional stimulus (US) with an brief electrical stimulus (1000V, 80μA), while continuing to use a sucrose application to the lips as the conditional stimulus (CS). With 15 paired CS-US presentations on a single day, we were able to elicit both short-term memory (STM) and long-term memory (LTM). The LTM persisted for at least one week. While STM was elicited with 5, 8, or 10 paired presentations of the CS-US on a single day, LTM was not. The new US used here was more consistent than the previously used US, and this stimulus consistency may explain why 15 paired CS-US presentations now result in LTM formation.

  15. Age Trends in Stimulus Overselectivity

    ERIC Educational Resources Information Center

    McHugh, Louise; Reed, Phil

    2007-01-01

    Stimulus overselectivity refers to the phenomenon whereby stimulus control over behavior is exerted only by a limited subset of the total number of stimuli present during discrimination learning. It often is displayed by individuals with autistic spectrum disorders or learning disabilities, but is not exclusive to those groups. The present studies…

  16. Stimulus control and associative learning.

    PubMed Central

    Williams, B A

    1984-01-01

    Interest in operant research on stimulus control has declined at the same time that much interest has burgeoned in nonoperant areas. Several examples of this shift toward traditional learning theory are considered, all of which have sponsored theoretical approaches that attempt to characterize the underlying associative units. These theoretical approaches are defended on the grounds that they have generated a deeper understanding of a variety of often puzzling phenomena. My projection is that future research will be determined even more strongly by theories about the structure of associations. Particular issues for which such discussion will have major impact include (1) whether conditional stimulus control is qualitatively different than simpler forms of stimulus control, (2) whether stimulus control is organized hierarchically, and (3) the origin of categories of stimulus equivalence. PMID:6520579

  17. Web-based tool for expert elicitation of the variogram

    NASA Astrophysics Data System (ADS)

    Truong, Phuong N.; Heuvelink, Gerard B. M.; Gosling, John Paul

    2013-02-01

    The variogram is the keystone of geostatistics. Estimation of the variogram is deficient and difficult when there are no or too few observations available due to budget constraints or physical and temporal obstacles. In such cases, expert knowledge can be an important source of information. Expert knowledge can also fulfil the increasing demand for an a priori variogram in Bayesian geostatistics and spatial sampling optimization. Formal expert elicitation provides a sound scientific basis to reliably and consistently extract knowledge from experts. In this study, we aimed at applying existing statistical expert elicitation techniques to extract the variogram of a regionalized variable that is assumed to have either a multivariate normal or lognormal spatial probability distribution from expert knowledge. To achieve this, we developed an elicitation protocol and implemented it as a web-based tool to facilitate the elicitation of beliefs from multiple experts. Our protocol has two main rounds: elicitation of the marginal probability distribution and elicitation of the variogram. The web-based tool has three main components: a web interface for expert elicitation and feedback; a component for statistical computation and mathematical pooling of multiple experts' knowledge; and a database management component. Results from a test case study show that the protocol is adequate and that the online elicitation tool functions satisfactorily. The web-based tool is free to use and supports scientists to conveniently elicit the variogram of spatial random variables from experts. The source code is available from the journal FTP site under the GNU General Public License.

  18. Temporal characteristics of gustatory responses in rat parabrachial neurons vary by stimulus and chemosensitive neuron type.

    PubMed

    Geran, Laura; Travers, Susan

    2013-01-01

    It has been demonstrated that temporal features of spike trains can increase the amount of information available for gustatory processing. However, the nature of these temporal characteristics and their relationship to different taste qualities and neuron types are not well-defined. The present study analyzed the time course of taste responses from parabrachial (PBN) neurons elicited by multiple applications of "sweet" (sucrose), "salty" (NaCl), "sour" (citric acid), and "bitter" (quinine and cycloheximide) stimuli in an acute preparation. Time course varied significantly by taste stimulus and best-stimulus classification. Across neurons, the ensemble code for the three electrolytes was similar initially but quinine diverged from NaCl and acid during the second 500 ms of stimulation and all four qualities became distinct just after 1s. This temporal evolution was reflected in significantly broader tuning during the initial response. Metric space analyses of quality discrimination by individual neurons showed that increases in information (H) afforded by temporal factors was usually explained by differences in rate envelope, which had a greater impact during the initial 2s (22.5% increase in H) compared to the later response (9.5%). Moreover, timing had a differential impact according to cell type, with between-quality discrimination in neurons activated maximally by NaCl or citric acid most affected. Timing was also found to dramatically improve within-quality discrimination (80% increase in H) in neurons that responded optimally to bitter stimuli (B-best). Spikes from B-best neurons were also more likely to occur in bursts. These findings suggest that among PBN taste neurons, time-dependent increases in mutual information can arise from stimulus- and neuron-specific differences in response envelope during the initial dynamic period. A stable rate code predominates in later epochs.

  19. Effect of white noise "masking" on vestibular evoked potentials recorded using different stimulus modalities.

    PubMed

    Freeman, S; Plotnik, M; Elidan, J; Rosen, L J; Sohmer, H

    1999-01-01

    Short latency vestibular evoked potentials (VsEPs) to linear acceleration impulses (L-VsEPs) are initiated in the otolith organs (saccule and utricle). Some of the saccule afferents have been reported to respond not only to linear acceleration, but also to high intensity acoustic stimuli. If so, the L-VsEP recorded from the saccule (elicited with the stimulus orientated relative to the head so as to optimally activate the saccule, i.e. stimulus in the vertical plane, Z-VsEP) should be reduced during high intensity broad band noise (BBN) "masking". Conversely, the utricular afferents have been reported to be less auditory-sensitive. Therefore, an L-VsEP which is mainly utricular in origin (stimulus in the horizontal plane, X-VsEP) should be less affected by this noise "masking". This was investigated in rats by recording X-VsEPs and Z-VsEPs and angular VsEPs (A-VsEPs), originating in the lateral semi-circular canals, before, during and after exposure to short duration, high intensity (113 dB SPL) BBN. This intensity completely masked auditory nerve evoked responses. The Z-VsEP did appear to be slightly more affected by the noise "masking" than the X-VsEP, implying the presence of more auditory-sensitive elements in the saccule. The A-VsEP was also affected by the BBN. The overall effect was relatively small (on average, 10-25% depression of the first wave of the different VsEPs). The responses showed recovery 5 min later. PMID:10380734

  20. Unconsciously elicited perceptual prior

    PubMed Central

    Chang, Raymond; Baria, Alexis T.; Flounders, Matthew W.; He, Biyu J.

    2016-01-01

    Increasing evidence over the past decade suggests that vision is not simply a passive, feed-forward process in which cortical areas relay progressively more abstract information to those higher up in the visual hierarchy, but rather an inferential process with top-down processes actively guiding and shaping perception. However, one major question that persists is whether such processes can be influenced by unconsciously perceived stimuli. Recent psychophysics and neuroimaging studies have revealed that while consciously perceived stimuli elicit stronger responses in higher visual and frontoparietal areas than those that fail to reach conscious awareness, the latter can still drive high-level brain and behavioral responses. We investigated whether unconscious processing of a masked natural image could facilitate subsequent conscious recognition of its degraded counterpart (a black-and-white “Mooney” image) presented many seconds later. We found that this is indeed the case, suggesting that conscious vision may be influenced by priors established by unconscious processing of a fleeting image. PMID:27595010

  1. Nociceptive-Evoked Potentials Are Sensitive to Behaviorally Relevant Stimulus Displacements in Egocentric Coordinates

    PubMed Central

    Di Stefano, G.; Stubbs, M. T.; Djeugam, B.; Liang, M.

    2016-01-01

    Abstract Feature selection has been extensively studied in the context of goal-directed behavior, where it is heavily driven by top-down factors. A more primitive version of this function is the detection of bottom-up changes in stimulus features in the environment. Indeed, the nervous system is tuned to detect fast-rising, intense stimuli that are likely to reflect threats, such as nociceptive somatosensory stimuli. These stimuli elicit large brain potentials maximal at the scalp vertex. When elicited by nociceptive laser stimuli, these responses are labeled laser-evoked potentials (LEPs). Although it has been shown that changes in stimulus modality and increases in stimulus intensity evoke large LEPs, it has yet to be determined whether stimulus displacements affect the amplitude of the main LEP waves (N1, N2, and P2). Here, in three experiments, we identified a set of rules that the human nervous system obeys to identify changes in the spatial location of a nociceptive stimulus. We showed that the N2 wave is sensitive to: (1) large displacements between consecutive stimuli in egocentric, but not somatotopic coordinates; and (2) displacements that entail a behaviorally relevant change in the stimulus location. These findings indicate that nociceptive-evoked vertex potentials are sensitive to behaviorally relevant changes in the location of a nociceptive stimulus with respect to the body, and that the hand is a particularly behaviorally important site. PMID:27419217

  2. Nociceptive-Evoked Potentials Are Sensitive to Behaviorally Relevant Stimulus Displacements in Egocentric Coordinates.

    PubMed

    Moayedi, M; Di Stefano, G; Stubbs, M T; Djeugam, B; Liang, M; Iannetti, G D

    2016-01-01

    Feature selection has been extensively studied in the context of goal-directed behavior, where it is heavily driven by top-down factors. A more primitive version of this function is the detection of bottom-up changes in stimulus features in the environment. Indeed, the nervous system is tuned to detect fast-rising, intense stimuli that are likely to reflect threats, such as nociceptive somatosensory stimuli. These stimuli elicit large brain potentials maximal at the scalp vertex. When elicited by nociceptive laser stimuli, these responses are labeled laser-evoked potentials (LEPs). Although it has been shown that changes in stimulus modality and increases in stimulus intensity evoke large LEPs, it has yet to be determined whether stimulus displacements affect the amplitude of the main LEP waves (N1, N2, and P2). Here, in three experiments, we identified a set of rules that the human nervous system obeys to identify changes in the spatial location of a nociceptive stimulus. We showed that the N2 wave is sensitive to: (1) large displacements between consecutive stimuli in egocentric, but not somatotopic coordinates; and (2) displacements that entail a behaviorally relevant change in the stimulus location. These findings indicate that nociceptive-evoked vertex potentials are sensitive to behaviorally relevant changes in the location of a nociceptive stimulus with respect to the body, and that the hand is a particularly behaviorally important site. PMID:27419217

  3. Stimulus Structure, Discrimination, and Interference

    ERIC Educational Resources Information Center

    Runquist, Willard N.

    1975-01-01

    The general purpose of this experiment was to determine whether differences in stimulus discrimination, as determined by the MIR (missing-item recognition) test, are correlated with interference in recall, as demanded by the discriminative coding hypothesis. (Author/RK)

  4. Auditory modulation of wind-elicited walking behavior in the cricket Gryllus bimaculatus.

    PubMed

    Fukutomi, Matasaburo; Someya, Makoto; Ogawa, Hiroto

    2015-12-01

    Animals flexibly change their locomotion triggered by an identical stimulus depending on the environmental context and behavioral state. This indicates that additional sensory inputs in different modality from the stimulus triggering the escape response affect the neuronal circuit governing that behavior. However, how the spatio-temporal relationships between these two stimuli effect a behavioral change remains unknown. We studied this question, using crickets, which respond to a short air-puff by oriented walking activity mediated by the cercal sensory system. In addition, an acoustic stimulus, such as conspecific 'song' received by the tympanal organ, elicits a distinct oriented locomotion termed phonotaxis. In this study, we examined the cross-modal effects on wind-elicited walking when an acoustic stimulus was preceded by an air-puff and tested whether the auditory modulation depends on the coincidence of the direction of both stimuli. A preceding 10 kHz pure tone biased the wind-elicited walking in a backward direction and elevated a threshold of the wind-elicited response, whereas other movement parameters, including turn angle, reaction time, walking speed and distance were unaffected. The auditory modulations, however, did not depend on the coincidence of the stimulus directions. A preceding sound consistently altered the wind-elicited walking direction and response probability throughout the experimental sessions, meaning that the auditory modulation did not result from previous experience or associative learning. These results suggest that the cricket nervous system is able to integrate auditory and air-puff stimuli, and modulate the wind-elicited escape behavior depending on the acoustic context. PMID:26519512

  5. Effect of stimulus size and luminance on the rod-, cone-, and melanopsin-mediated pupillary light reflex.

    PubMed

    Park, Jason C; McAnany, J Jason

    2015-01-01

    This study determined if the pupillary light reflex (PLR) driven by brief stimulus presentations can be accounted for by the product of stimulus luminance and area (i.e., corneal flux density, CFD) under conditions biased toward the rod, cone, and melanopsin pathways. Five visually normal subjects participated in the study. Stimuli consisted of 1-s short- and long-wavelength flashes that spanned a large range of luminance and angular subtense. The stimuli were presented in the central visual field in the dark (rod and melanopsin conditions) and against a rod-suppressing short-wavelength background (cone condition). Rod- and cone-mediated PLRs were measured at the maximum constriction after stimulus onset whereas the melanopsin-mediated PLR was measured 5-7 s after stimulus offset. The rod- and melanopsin-mediated PLRs were well accounted for by CFD, such that doubling the stimulus luminance had the same effect on the PLR as doubling the stimulus area. Melanopsin-mediated PLRs were elicited only by short-wavelength, large (>16°) stimuli with luminance greater than 10 cd/m(2), but when present, the melanopsin-mediated PLR was well accounted for by CFD. In contrast, CFD could not account for the cone-mediated PLR because the PLR was approximately independent of stimulus size but strongly dependent on stimulus luminance. These findings highlight important differences in how stimulus luminance and size combine to govern the PLR elicited by brief flashes under rod-, cone-, and melanopsin-mediated conditions.

  6. Carving Executive Control at Its Joints: Working Memory Capacity Predicts Stimulus-Stimulus, but Not Stimulus-Response, Conflict

    ERIC Educational Resources Information Center

    Meier, Matt E.; Kane, Michael J.

    2015-01-01

    Three experiments examined the relation between working memory capacity (WMC) and 2 different forms of cognitive conflict: stimulus-stimulus (S-S) and stimulus-response (S-R) interference. Our goal was to test whether WMC's relation to conflict-task performance is mediated by stimulus-identification processes (captured by S-S conflict),…

  7. Stimulus-specific contrast effects during operant discrimination learning1

    PubMed Central

    Malone, John C.

    1975-01-01

    In two experiments, pigeons' responding was equally reinforced in the presence of four line-orientation stimuli. Responding was then reinforced when only two of the four orientation stimuli were present; the remaining two orientations appeared during extinction. Response rates were often highest in the stimulus adjacent to the orientations presented during extinction and often lowest in that orientation adjacent to the orientations presented with reinforcement. These effects were stronger and more persistent when the stimuli were separated by a smaller angle, rendering the discrimination more difficult. These and other data suggest that discrimination training may not be accurately explained in terms of the simple effects of reinforcement and nonreinforcement associated with isolated stimuli, nor by accounts that depend upon stimulus generalization. Recent accounts of contrast that depend upon “emotionality” produced by nonreinforced responding or upon reinforcement-elicited responses are also difficult to apply to these data. PMID:16811879

  8. What monitor can replace the cathode-ray tube for visual stimulation to elicit multifocal electroretinograms?

    PubMed

    Matsumoto, Celso Soiti; Shinoda, Kei; Matsumoto, Harue; Seki, Keisuke; Nagasaka, Eiichiro; Iwata, Takeshi; Mizota, Atsushi

    2014-01-01

    To compare a conventional cathode-ray tube (CRT) screen to organic light-emitting diode (OLED) and liquid crystal display (LCD) screens as visual stimulators to elicit multifocal electroretinograms (mfERGs), mfERGs were recorded from seven eyes of seven healthy volunteers (21 ± 2 years). The mfERGs elicited by a conventional CRT screen (S710, Compaq Computer Co.) were compared to those elicited by a studio-grade master OLED monitor (PVM-1741, Sony, Japan) and a conventional LCD (S1721, Flexscan, Eizo Nanao Corp., Japan). The luminance changes of each monitor were measured with a photodiode. CRT, OLED, and LCD screens with a frame frequency of 60 Hz were studied. A hexagonal stimulus array with 61 stimulus elements was created on each monitor. The serial white stimuli of the OLED screen at 60 Hz did not fuse, and that of the LCD screens fused. The amplitudes of P1 and P2 of the first-order kernels of the mfERGs were not significantly different from those elicited by the CRT and OLED screens, and the P1 amplitude of the first-order kernel elicited by the LCD stimuli was significantly smaller than that elicited by the CRT in all the groups of the averaged hexagonal elements. The implicit times were approximately 10 ms longer in almost all components elicited by the LCD screen compared to those elicited by the CRT screen. The mfERGs elicited by monitors other than the CRT should be carefully interpreted, especially those elicited by LCD screens. The OLED had good performance, and we conclude that it can replace the CRT as a stimulator for mfERGs; however, a collection of normative data is recommended.

  9. Strategic allocation of attention reduces temporally predictable stimulus conflict

    PubMed Central

    Appelbaum, L. Gregory; Boehler, Carsten N.; Won, Robert; Davis, Lauren; Woldorff, Marty G.

    2013-01-01

    Humans are able to continuously monitor environmental situations and adjust their behavioral strategies to optimize performance. Here we investigate the behavioral and brain adjustments that occur when conflicting stimulus elements are, or are not, temporally predictable. Event-related potentials (ERPs) were collected while manual-response variants of the Stroop task were performed in which the stimulus onset asynchronies (SOAs) between the relevant-color and irrelevant-word stimulus components were either randomly intermixed, or held constant, within each experimental run. Results indicated that the size of both the neural and behavioral effects of stimulus incongruency varied with the temporal arrangement of the stimulus components, such that the random-SOA arrangements produced the greatest incongruency effects at the earliest irrelevant-first SOA (−200 ms) and the constant-SOA arrangements produced the greatest effects with simultaneous presentation. These differences in conflict processing were accompanied by rapid (~150 ms) modulations of the sensory ERPs to the irrelevant distracter components when they occurred consistently first. These effects suggest that individuals are able to strategically allocate attention in time to mitigate the influence of a temporally predictable distracter. As these adjustments are instantiated by the subjects without instruction, they reveal a form of rapid strategic learning for dealing with temporally predictable stimulus incongruency. PMID:22360623

  10. Stimulus-response compatibility with body parts: a study with hands.

    PubMed

    Lameira, Allan Pablo; Pereira, Antônio; Fraga-Filho, Roberto Sena; Gawryszewski, Luiz G

    2015-07-01

    Stimulus-response compatibility (SRC) effects are classified depending on the way that the elements of the stimulus and response sets interact, influencing both the speed and accuracy of the motor response. This is particularly important for social stimuli, such as hands. However, the stimuli used in most SRC studies are often simple or abstract figures. Our main goal in the present work was to investigate how task ensembles containing body parts (hands) as stimuli fit into Kornblum's taxonomy expressed in the dimensional overlap model. Specifically, we test whether hand stimuli elicit Simon or spatial Stroop effects in a SRC task. We set up two experiments using either hands or arrows as stimuli. Our results demonstrate that hands elicit a Simon effect in a SRC task. However, different from arrows, which constitute Type 8 Kornblum's ensembles, hands do not elicit a spatial Stroop effect and form Type 3 ensembles.

  11. Conditioned craving cues elicit an automatic approach tendency.

    PubMed

    Van Gucht, Dinska; Vansteenwegen, Debora; Van den Bergh, Omer; Beckers, Tom

    2008-10-01

    In two experiments, we used a Pavlovian differential conditioning procedure to induce craving for chocolate. As a result of repeated pairing with chocolate intake, initially neutral cues came to elicit an automatic approach tendency in a speeded stimulus-response compatibility reaction time task. This automatic approach tendency, moreover, seemed to be sensitive to manipulations of extinction and renewal in the Pavlovian conditioning procedure. These findings corroborate and extend previous reports of automatic approach tendencies elicited by substance-relevant cues in addiction, while controlling for alternative accounts for such observations. Moreover, our data lend support to and extend learning models of cue-induced craving and addiction. Finally, we argue that the procedure we present here provides an ecologically valid behavioural tool that allows studying processes involved in cue-induced craving, addiction and relapse without relying on verbal report. PMID:18684435

  12. N2pc is modulated by stimulus-stimulus, but not by stimulus-response incompatibilities.

    PubMed

    Cespón, J; Galdo-Álvarez, S; Díaz, F

    2013-04-01

    Studies of the N2pc in Simon-type tasks have revealed inconsistent results. That is, N2pc was only modulated when a stimulus-stimulus (S-S) overlap covaries with the stimulus-response (S-R) overlap. The present study aimed to establish whether N2pc is modulated by the S-R or by the S-S overlap. Therefore, we designed a Simon task requiring response to a colour stimulus (an arrow) with two irrelevant dimensions (position and direction). The following conditions were thus generated: compatible direction-compatible position (CDCP); incompatible direction-compatible position (IDCP); compatible direction-incompatible position (CDIP); and incompatible direction-incompatible position (IDIP). In IDCP and CDIP, both irrelevant dimensions conveyed contradictory spatial information (S-S incompatibility), while compatibility between both irrelevant dimensions occurred in CDCP and IDIP (the direction indicated was compatible with stimulus position). The N2pc amplitude was smaller in IDCP and CDIP than in CDCP and IDIP, what suggests that N2pc was modulated by S-S incompatibility and not by S-R incompatibilities. PMID:23380335

  13. Independent processing of stimulus-stimulus and stimulus-response conflicts.

    PubMed

    Li, Qi; Nan, Weizhi; Wang, Kai; Liu, Xun

    2014-01-01

    The dimensional overlap (DO) model proposes distinct mechanisms for stimulus-stimulus (S-S) and stimulus-response (S-R) conflict effects. Many studies have examined the independence of S-S and S-R conflict effects in the color-word Stroop and Simon tasks. However, confounds exist between the distinction of DO (i.e., S-S dimensional overlap compared with S-R dimensional overlap) and the distinction of stimulus attributes (e.g., color compared with spatial location; semantic compared with nonsemantic information), which may hinder interpretation of the independence of S-S and S-R conflicts. A spatial Stroop (word) task and a spatial Stroop (arrow) task were combined with a Simon task in Experiments 1 and 2, respectively to eliminate these confounds of stimulus attributes. The results showed that S-S and S-R conflicts affected performance additively. There was no significant correlation across participants. These findings lend further support to independent processing of S-S and S-R conflicts as it is outlined in the taxonomy of DO.

  14. "Turning back the clock" on serial-stimulus sign tracking.

    PubMed Central

    Allan, R W; Matthews, T J

    1991-01-01

    Two experiments examined the effects of a negative (setback) response contingency on key pecking engendered by a changing light-intensity stimulus clock (ramp stimulus) signaling fixed-time 30-s food deliveries. The response contingency specified that responses would immediately decrease the light-intensity value, and, because food was delivered only after the highest intensity value was presented, would delay food delivery by 1 s for each response. The first experiment examined the acquisition and maintenance of responding for a group trained with the contingency in effect and for a group trained on a response-independent schedule with the ramp stimulus prior to introduction of the contingency. The first group acquired low rates of key pecking, and, after considerable exposure to the contingency, those rates were reduced to low levels. The rates of responding for the second group were reduced very rapidly (within four to five trials) after introduction of the setback contingency. For both groups, rates of responding increased for all but 1 bird when the contingency was removed. A second experiment compared the separate effects of each part of the response contingency. One group was exposed only to the stimulus setback (stimulus only), and a second group was exposed only to the delay of the reinforcer (delay only). The stimulus-only group's rates of responding were immediately reduced to moderate levels, but for most of the birds, these rates recovered quickly when the contingency was removed. The delay-only groups's rates decreased after several trials, to very low levels, and recovery of responding took several sessions once the contingency was removed. The results suggest that (a) sign-tracking behavior elicited by an added clock stimulus may be reduced rapidly and persistently when a setback contingency is imposed, and (b) the success of the contingency is due both to response-dependent stimulus change and response-dependent alterations in the frequency of food

  15. Stimulus Effects on Local Preference: Stimulus-Response Contingencies, Stimulus-Food Pairing, and Stimulus-Food Correlation

    ERIC Educational Resources Information Center

    Davison, Michael; Baum, William M.

    2010-01-01

    Four pigeons were trained in a procedure in which concurrent-schedule food ratios changed unpredictably across seven unsignaled components after 10 food deliveries. Additional green-key stimulus presentations also occurred on the two alternatives, sometimes in the same ratio as the component food ratio, and sometimes in the inverse ratio. In eight…

  16. Defining the Stimulus - A Memoir

    PubMed Central

    Terrace, Herbert

    2010-01-01

    The eminent psychophysicist, S. S. Stevens, once remarked that, “the basic problem of psychology was the definition of the stimulus” (Stevens, 1951, p. 46). By expanding the traditional definition of the stimulus, the study of animal learning has metamorphosed into animal cognition. The main impetus for that change was the recognition that it is often necessary to postulate a representation between the traditional S and R of learning theory. Representations allow a subject to re-present a stimulus it learned previously that is currently absent. Thus, in delayed-matching-to-sample, one has to assume that a subject responds to a representation of the sample during test if it responds correctly. Other examples, to name but a few, include concept formation, spatial memory, serial memory, learning a numerical rule, imitation and metacognition. Whereas a representation used to be regarded as a mentalistic phenomenon that was unworthy of scientific inquiry, it can now be operationally defined. To accommodate representations, the traditional discriminative stimulus has to be expanded to allow for the role of representations. The resulting composite can account for a significantly larger portion of the variance of performance measures than the exteroceptive stimulus could by itself. PMID:19969047

  17. Age trends in stimulus overselectivity.

    PubMed

    McHugh, Louise; Reed, Phil

    2007-11-01

    Stimulus overselectivity refers to the phenomenon whereby stimulus control over behavior is exerted only by a limited subset of the total number of stimuli present during discrimination learning. It often is displayed by individuals with autistic spectrum disorders or learning disabilities, but is not exclusive to those groups. The present studies investigated the impact of aging on stimulus control and overselectivity. Three age groups--18-22, 47-55, and 70-80 year olds-were studied in two experiments. All participants were trained on a simple discrimination task, randomly assigned to one of two conditions (either with or without a distractor task), and then tested for the emergence of overselectivity (Experiment 1). In Experiment 2 responding controlled by the overselected stimulus elements was reduced by introducing a verbal punisher. In subsequent tests, control of behavior by the previously underselected elements from Experiment 1 was enhanced across the two younger age groups but not the oldest group of participants. The results are discussed in relation to the attention-deficit and overshadowing accounts of overselectivity. PMID:18047227

  18. Acquired Equivalence Changes Stimulus Representations

    ERIC Educational Resources Information Center

    Meeter, M.; Shohamy, D.; Myers, C. E.

    2009-01-01

    Acquired equivalence is a paradigm in which generalization is increased between two superficially dissimilar stimuli (or antecedents) that have previously been associated with similar outcomes (or consequents). Several possible mechanisms have been proposed, including changes in stimulus representations, either in the form of added associations or…

  19. Benefits of Stimulus Exposure: Developmental Learning Independent of Task Performance

    PubMed Central

    Green, David B.; Ohlemacher, Jocelyn; Rosen, Merri J.

    2016-01-01

    Perceptual learning (training-induced performance improvement) can be elicited by task-irrelevant stimulus exposure in humans. In contrast, task-irrelevant stimulus exposure in animals typically disrupts perception in juveniles while causing little to no effect in adults. This may be due to the extent of exposure, which is brief in humans while chronic in animals. Here we assessed the effects of short bouts of passive stimulus exposure on learning during development in gerbils, compared with non-passive stimulus exposure (i.e., during testing). We used prepulse inhibition of the acoustic startle response, a method that can be applied at any age, to measure gap detection thresholds across four age groups, spanning development. First, we showed that both gap detection thresholds and gap detection learning across sessions displayed a long developmental trajectory, improving throughout the juvenile period. Additionally, we demonstrated larger within- and across-animal performance variability in younger animals. These results are generally consistent with results in humans, where there are extended developmental trajectories for both the perception of temporally-varying signals, and the effects of perceptual training, as well as increased variability and poorer performance consistency in children. We then chose an age (mid-juveniles) that displayed clear learning over sessions in order to assess effects of brief passive stimulus exposure on this learning. We compared learning in mid-juveniles exposed to either gap detection testing (gaps paired with startles) or equivalent gap exposure without testing (gaps alone) for three sessions. Learning was equivalent in both these groups and better than both naïve age-matched animals and controls receiving no gap exposure but only startle testing. Thus, short bouts of exposure to gaps independent of task performance is sufficient to induce learning at this age, and is as effective as gap detection testing. PMID:27378837

  20. Benefits of Stimulus Exposure: Developmental Learning Independent of Task Performance.

    PubMed

    Green, David B; Ohlemacher, Jocelyn; Rosen, Merri J

    2016-01-01

    Perceptual learning (training-induced performance improvement) can be elicited by task-irrelevant stimulus exposure in humans. In contrast, task-irrelevant stimulus exposure in animals typically disrupts perception in juveniles while causing little to no effect in adults. This may be due to the extent of exposure, which is brief in humans while chronic in animals. Here we assessed the effects of short bouts of passive stimulus exposure on learning during development in gerbils, compared with non-passive stimulus exposure (i.e., during testing). We used prepulse inhibition of the acoustic startle response, a method that can be applied at any age, to measure gap detection thresholds across four age groups, spanning development. First, we showed that both gap detection thresholds and gap detection learning across sessions displayed a long developmental trajectory, improving throughout the juvenile period. Additionally, we demonstrated larger within- and across-animal performance variability in younger animals. These results are generally consistent with results in humans, where there are extended developmental trajectories for both the perception of temporally-varying signals, and the effects of perceptual training, as well as increased variability and poorer performance consistency in children. We then chose an age (mid-juveniles) that displayed clear learning over sessions in order to assess effects of brief passive stimulus exposure on this learning. We compared learning in mid-juveniles exposed to either gap detection testing (gaps paired with startles) or equivalent gap exposure without testing (gaps alone) for three sessions. Learning was equivalent in both these groups and better than both naïve age-matched animals and controls receiving no gap exposure but only startle testing. Thus, short bouts of exposure to gaps independent of task performance is sufficient to induce learning at this age, and is as effective as gap detection testing.

  1. Benefits of Stimulus Exposure: Developmental Learning Independent of Task Performance.

    PubMed

    Green, David B; Ohlemacher, Jocelyn; Rosen, Merri J

    2016-01-01

    Perceptual learning (training-induced performance improvement) can be elicited by task-irrelevant stimulus exposure in humans. In contrast, task-irrelevant stimulus exposure in animals typically disrupts perception in juveniles while causing little to no effect in adults. This may be due to the extent of exposure, which is brief in humans while chronic in animals. Here we assessed the effects of short bouts of passive stimulus exposure on learning during development in gerbils, compared with non-passive stimulus exposure (i.e., during testing). We used prepulse inhibition of the acoustic startle response, a method that can be applied at any age, to measure gap detection thresholds across four age groups, spanning development. First, we showed that both gap detection thresholds and gap detection learning across sessions displayed a long developmental trajectory, improving throughout the juvenile period. Additionally, we demonstrated larger within- and across-animal performance variability in younger animals. These results are generally consistent with results in humans, where there are extended developmental trajectories for both the perception of temporally-varying signals, and the effects of perceptual training, as well as increased variability and poorer performance consistency in children. We then chose an age (mid-juveniles) that displayed clear learning over sessions in order to assess effects of brief passive stimulus exposure on this learning. We compared learning in mid-juveniles exposed to either gap detection testing (gaps paired with startles) or equivalent gap exposure without testing (gaps alone) for three sessions. Learning was equivalent in both these groups and better than both naïve age-matched animals and controls receiving no gap exposure but only startle testing. Thus, short bouts of exposure to gaps independent of task performance is sufficient to induce learning at this age, and is as effective as gap detection testing. PMID:27378837

  2. Perceived stimulus complexity and food preference development.

    PubMed

    Lévy, C M; MacRae, A; Köster, E P

    2006-11-01

    The importance of perceived complexity, a "collative property" as defined by [Berlyne, D. E. (1967). Arousal and reinforcement. In Nebraska symposium on motivation (pp. 1-110). University of Nebraska Press], to the dynamic development of preference was investigated. Eighty-six female and 82 male subjects rated their liking for and various collative properties of seven very similar orange drinks that differed only in perceived complexity as a result of adding small quantities of other flavours. This was done before and after giving each subject extended experience of one of the drinks, each being used equally often for this purpose. As predicted by the theory of [Dember, W. N., & Earl, R. W. (1957). Analysis of exploratory, manipulatory and curiosity behavior. Psychological Review, 64 (2), 91-96] exposure to a stimulus with a slightly higher complexity than an individual subject's optimally preferred level of perceived complexity, caused an upwards shift in that level, whereas exposure to a less complex stimulus had no such effect. Changes in the appreciation of the drinks predicted by the theory were also observed.

  3. Stimulus factors in motion perception and spatial orientation

    NASA Technical Reports Server (NTRS)

    Post, R. B.; Johnson, C. A.

    1984-01-01

    The Malcolm horizon utilizes a large projected light stimulus Peripheral Vision Horizon Device (PVHD) as an attitude indicator in order to achieve a more compelling sense of roll than is obtained with smaller devices. The basic principle is that the larger stimulus is more similar to visibility of a real horizon during roll, and does not require fixation and attention to the degree that smaller displays do. Successful implementation of such a device requires adjustment of the parameters of the visual stimulus so that its effects on motion perception and spatial orientation are optimized. With this purpose in mind, the effects of relevant image variables on the perception of object motion, self motion and spatial orientation are reviewed.

  4. Encoding of Stimulus Probability in Macaque Inferior Temporal Cortex.

    PubMed

    Bell, Andrew H; Summerfield, Christopher; Morin, Elyse L; Malecek, Nicholas J; Ungerleider, Leslie G

    2016-09-12

    Optimal perceptual decisions require sensory signals to be combined with prior information about stimulus probability. Although several theories propose that probabilistic information about stimulus occurrence is encoded in sensory cortex, evidence from neuronal recordings has not yet fully supported this view. We recorded activity from single neurons in inferior temporal cortex (IT) while monkeys performed a task that involved discriminating degraded images of faces and fruit. The relative probability of the cue being a face versus a fruit was manipulated by a latent variable that was not revealed to the monkeys and that changed unpredictably over the course of each recording session. In addition to responding to stimulus identity (face or fruit), population responses in IT encoded the long-term stimulus probability of whether a face or a fruit stimulus was more likely to occur. Face-responsive neurons showed reduced firing rates to expected faces, an effect consistent with "expectation suppression," but expected stimuli were decoded from multivariate population signals with greater accuracy. These findings support "predictive coding" theories, whereby neural signals in the mammalian visual system actively encode and update predictions about the local sensory environment.

  5. Interactions across Multiple Stimulus Dimensions in Primary Auditory Cortex

    PubMed Central

    Zhuo, Ran; Xue, Hongbo; Chambers, Anna R.; Kolaczyk, Eric; Polley, Daniel B.

    2016-01-01

    Although sensory cortex is thought to be important for the perception of complex objects, its specific role in representing complex stimuli remains unknown. Complex objects are rich in information along multiple stimulus dimensions. The position of cortex in the sensory hierarchy suggests that cortical neurons may integrate across these dimensions to form a more gestalt representation of auditory objects. Yet, studies of cortical neurons typically explore single or few dimensions due to the difficulty of determining optimal stimuli in a high dimensional stimulus space. Evolutionary algorithms (EAs) provide a potentially powerful approach for exploring multidimensional stimulus spaces based on real-time spike feedback, but two important issues arise in their application. First, it is unclear whether it is necessary to characterize cortical responses to multidimensional stimuli or whether it suffices to characterize cortical responses to a single dimension at a time. Second, quantitative methods for analyzing complex multidimensional data from an EA are lacking. Here, we apply a statistical method for nonlinear regression, the generalized additive model (GAM), to address these issues. The GAM quantitatively describes the dependence between neural response and all stimulus dimensions. We find that auditory cortical neurons in mice are sensitive to interactions across dimensions. These interactions are diverse across the population, indicating significant integration across stimulus dimensions in auditory cortex. This result strongly motivates using multidimensional stimuli in auditory cortex. Together, the EA and the GAM provide a novel quantitative paradigm for investigating neural coding of complex multidimensional stimuli in auditory and other sensory cortices.

  6. Interactions across Multiple Stimulus Dimensions in Primary Auditory Cortex.

    PubMed

    Sloas, David C; Zhuo, Ran; Xue, Hongbo; Chambers, Anna R; Kolaczyk, Eric; Polley, Daniel B; Sen, Kamal

    2016-01-01

    Although sensory cortex is thought to be important for the perception of complex objects, its specific role in representing complex stimuli remains unknown. Complex objects are rich in information along multiple stimulus dimensions. The position of cortex in the sensory hierarchy suggests that cortical neurons may integrate across these dimensions to form a more gestalt representation of auditory objects. Yet, studies of cortical neurons typically explore single or few dimensions due to the difficulty of determining optimal stimuli in a high dimensional stimulus space. Evolutionary algorithms (EAs) provide a potentially powerful approach for exploring multidimensional stimulus spaces based on real-time spike feedback, but two important issues arise in their application. First, it is unclear whether it is necessary to characterize cortical responses to multidimensional stimuli or whether it suffices to characterize cortical responses to a single dimension at a time. Second, quantitative methods for analyzing complex multidimensional data from an EA are lacking. Here, we apply a statistical method for nonlinear regression, the generalized additive model (GAM), to address these issues. The GAM quantitatively describes the dependence between neural response and all stimulus dimensions. We find that auditory cortical neurons in mice are sensitive to interactions across dimensions. These interactions are diverse across the population, indicating significant integration across stimulus dimensions in auditory cortex. This result strongly motivates using multidimensional stimuli in auditory cortex. Together, the EA and the GAM provide a novel quantitative paradigm for investigating neural coding of complex multidimensional stimuli in auditory and other sensory cortices.

  7. Interactions across Multiple Stimulus Dimensions in Primary Auditory Cortex

    PubMed Central

    Zhuo, Ran; Xue, Hongbo; Chambers, Anna R.; Kolaczyk, Eric; Polley, Daniel B.

    2016-01-01

    Although sensory cortex is thought to be important for the perception of complex objects, its specific role in representing complex stimuli remains unknown. Complex objects are rich in information along multiple stimulus dimensions. The position of cortex in the sensory hierarchy suggests that cortical neurons may integrate across these dimensions to form a more gestalt representation of auditory objects. Yet, studies of cortical neurons typically explore single or few dimensions due to the difficulty of determining optimal stimuli in a high dimensional stimulus space. Evolutionary algorithms (EAs) provide a potentially powerful approach for exploring multidimensional stimulus spaces based on real-time spike feedback, but two important issues arise in their application. First, it is unclear whether it is necessary to characterize cortical responses to multidimensional stimuli or whether it suffices to characterize cortical responses to a single dimension at a time. Second, quantitative methods for analyzing complex multidimensional data from an EA are lacking. Here, we apply a statistical method for nonlinear regression, the generalized additive model (GAM), to address these issues. The GAM quantitatively describes the dependence between neural response and all stimulus dimensions. We find that auditory cortical neurons in mice are sensitive to interactions across dimensions. These interactions are diverse across the population, indicating significant integration across stimulus dimensions in auditory cortex. This result strongly motivates using multidimensional stimuli in auditory cortex. Together, the EA and the GAM provide a novel quantitative paradigm for investigating neural coding of complex multidimensional stimuli in auditory and other sensory cortices. PMID:27622211

  8. Interactions across Multiple Stimulus Dimensions in Primary Auditory Cortex.

    PubMed

    Sloas, David C; Zhuo, Ran; Xue, Hongbo; Chambers, Anna R; Kolaczyk, Eric; Polley, Daniel B; Sen, Kamal

    2016-01-01

    Although sensory cortex is thought to be important for the perception of complex objects, its specific role in representing complex stimuli remains unknown. Complex objects are rich in information along multiple stimulus dimensions. The position of cortex in the sensory hierarchy suggests that cortical neurons may integrate across these dimensions to form a more gestalt representation of auditory objects. Yet, studies of cortical neurons typically explore single or few dimensions due to the difficulty of determining optimal stimuli in a high dimensional stimulus space. Evolutionary algorithms (EAs) provide a potentially powerful approach for exploring multidimensional stimulus spaces based on real-time spike feedback, but two important issues arise in their application. First, it is unclear whether it is necessary to characterize cortical responses to multidimensional stimuli or whether it suffices to characterize cortical responses to a single dimension at a time. Second, quantitative methods for analyzing complex multidimensional data from an EA are lacking. Here, we apply a statistical method for nonlinear regression, the generalized additive model (GAM), to address these issues. The GAM quantitatively describes the dependence between neural response and all stimulus dimensions. We find that auditory cortical neurons in mice are sensitive to interactions across dimensions. These interactions are diverse across the population, indicating significant integration across stimulus dimensions in auditory cortex. This result strongly motivates using multidimensional stimuli in auditory cortex. Together, the EA and the GAM provide a novel quantitative paradigm for investigating neural coding of complex multidimensional stimuli in auditory and other sensory cortices. PMID:27622211

  9. Stimulus Statistics Change Sounds from Near-Indiscriminable to Hyperdiscriminable.

    PubMed

    Stilp, Christian E; Kluender, Keith R

    2016-01-01

    Objects and events in the sensory environment are generally predictable, making most of the energy impinging upon sensory transducers redundant. Given this fact, efficient sensory systems should detect, extract, and exploit predictability in order to optimize sensitivity to less predictable inputs that are, by definition, more informative. Not only are perceptual systems sensitive to changes in physical stimulus properties, but growing evidence reveals sensitivity both to relative predictability of stimuli and to co-occurrence of stimulus attributes within stimuli. Recent results revealed that auditory perception rapidly reorganizes to efficiently capture covariance among stimulus attributes. Acoustic properties per se were perceptually abandoned, and sounds were instead processed relative to patterns of co-occurrence. Here, we show that listeners' ability to distinguish sounds from one another is driven primarily by the extent to which they are consistent or inconsistent with patterns of covariation among stimulus attributes and, to a lesser extent, whether they are heard frequently or infrequently. When sounds were heard frequently and deviated minimally from the prevailing pattern of covariance among attributes, they were poorly discriminated from one another. In stark contrast, when sounds were heard rarely and markedly violated the pattern of covariance, they became hyperdiscriminable with discrimination performance beyond apparent limits of the auditory system. Plausible cortical candidates underlying these dramatic changes in perceptual organization are discussed. These findings support efficient coding of stimulus statistical structure as a model for both perceptual and neural organization. PMID:27508391

  10. Stimulus Statistics Change Sounds from Near-Indiscriminable to Hyperdiscriminable

    PubMed Central

    Stilp, Christian E.

    2016-01-01

    Objects and events in the sensory environment are generally predictable, making most of the energy impinging upon sensory transducers redundant. Given this fact, efficient sensory systems should detect, extract, and exploit predictability in order to optimize sensitivity to less predictable inputs that are, by definition, more informative. Not only are perceptual systems sensitive to changes in physical stimulus properties, but growing evidence reveals sensitivity both to relative predictability of stimuli and to co-occurrence of stimulus attributes within stimuli. Recent results revealed that auditory perception rapidly reorganizes to efficiently capture covariance among stimulus attributes. Acoustic properties per se were perceptually abandoned, and sounds were instead processed relative to patterns of co-occurrence. Here, we show that listeners’ ability to distinguish sounds from one another is driven primarily by the extent to which they are consistent or inconsistent with patterns of covariation among stimulus attributes and, to a lesser extent, whether they are heard frequently or infrequently. When sounds were heard frequently and deviated minimally from the prevailing pattern of covariance among attributes, they were poorly discriminated from one another. In stark contrast, when sounds were heard rarely and markedly violated the pattern of covariance, they became hyperdiscriminable with discrimination performance beyond apparent limits of the auditory system. Plausible cortical candidates underlying these dramatic changes in perceptual organization are discussed. These findings support efficient coding of stimulus statistical structure as a model for both perceptual and neural organization. PMID:27508391

  11. The Adaptation of the Moth Pheromone Receptor Neuron to its Natural Stimulus

    NASA Astrophysics Data System (ADS)

    Kostal, Lubomir; Lansky, Petr; Rospars, Jean-Pierre

    2008-07-01

    We analyze the first phase of information transduction in the model of the olfactory receptor neuron of the male moth Antheraea polyphemus. We predict such stimulus characteristics that enable the system to perform optimally, i.e., to transfer as much information as possible. Few a priori constraints on the nature of stimulus and stimulus-to-signal transduction are assumed. The results are given in terms of stimulus distributions and intermittency factors which makes direct comparison with experimental data possible. Optimal stimulus is approximatelly described by exponential or log-normal probability density function which is in agreement with experiment and the predicted intermittency factors fall within the lowest range of observed values. The results are discussed with respect to electroantennogram measurements and behavioral observations.

  12. Observing Behavior and Atypically Restricted Stimulus Control

    ERIC Educational Resources Information Center

    Dube, William V.; Dickson, Chata A.; Balsamo, Lyn M.; O'Donnell, Kristin Lombard; Tomanari, Gerson Y.; Farren, Kevin M.; Wheeler, Emily E.; McIlvane, William J.

    2010-01-01

    Restricted stimulus control refers to discrimination learning with atypical limitations in the range of controlling stimuli or stimulus features. In the study reported here, 4 normally capable individuals and 10 individuals with intellectual disabilities (ID) performed two-sample delayed matching to sample. Sample-stimulus observing was recorded…

  13. Temporal and spectral profiles of stimulus-stimulus and stimulus-response conflict processing.

    PubMed

    Wang, Kai; Li, Qi; Zheng, Ya; Wang, Hongbin; Liu, Xun

    2014-04-01

    The ability to detect and resolve conflict is an essential function of cognitive control. Laboratory studies often use stimulus-response-compatibility (SRC) tasks to examine conflict processing in order to elucidate the mechanism and modular organization of cognitive control. Inspired by two influential theories regarding cognitive control, the conflict monitoring theory (Botvinick, Braver, Barch, Carter, & Cohen, 2001) and dimensional overlap taxonomy (Kornblum, Hasbroucq, & Osman, 1990), we explored the temporal and spectral similarities and differences between processing of stimulus-stimulus (S-S) and stimulus-response (S-R) conflicts with event related potential (ERP) and time-frequency measures. We predicted that processing of S-S conflict starts earlier than that of S-R conflict and that the two types of conflict may involve different frequency bands. Participants were asked to perform two parallel SRC tasks, both combining the Stroop task (involving S-S conflict) and Simon task (involving S-R conflict). ERP results showed pronounced SRC effects (incongruent vs. congruent) on N2 and P3 components for both S-S and S-R conflicts. In both tasks, SRC effects of S-S conflict took place earlier than those of S-R conflict. Time-frequency analysis revealed that both types of SRC effects modulated theta and alpha bands, while S-R conflict effects additionally modulated power in the beta band. These results indicated that although S-S and S-R conflict processing shared considerable ERP and time-frequency properties, they differed in temporal and spectral dynamics. We suggest that the modular organization of cognitive control should take both commonality and distinction of S-S and S-R conflict processing into consideration.

  14. The adequate stimulus for avian short latency vestibular responses to linear translation

    NASA Technical Reports Server (NTRS)

    Jones, T. A.; Jones, S. M.; Colbert, S.

    1998-01-01

    Transient linear acceleration stimuli have been shown to elicit eighth nerve vestibular compound action potentials in birds and mammals. The present study was undertaken to better define the nature of the adequate stimulus for neurons generating the response in the chicken (Gallus domesticus). In particular, the study evaluated the question of whether the neurons studied are most sensitive to the maximum level of linear acceleration achieved or to the rate of change in acceleration (da/dt, or jerk). To do this, vestibular response thresholds were measured as a function of stimulus onset slope. Traditional computer signal averaging was used to record responses to pulsed linear acceleration stimuli. Stimulus onset slope was systematically varied. Acceleration thresholds decreased with increasing stimulus onset slope (decreasing stimulus rise time). When stimuli were expressed in units of jerk (g/ms), thresholds were virtually constant for all stimulus rise times. Moreover, stimuli having identical jerk magnitudes but widely varying peak acceleration levels produced virtually identical responses. Vestibular response thresholds, latencies and amplitudes appear to be determined strictly by stimulus jerk magnitudes. Stimulus attributes such as peak acceleration or rise time alone do not provide sufficient information to predict response parameter quantities. Indeed, the major response parameters were shown to be virtually independent of peak acceleration levels or rise time when these stimulus features were isolated and considered separately. It is concluded that the neurons generating short latency vestibular evoked potentials do so as "jerk encoders" in the chicken. Primary afferents classified as "irregular", and which traditionally fall into the broad category of "dynamic" or "phasic" neurons, would seem to be the most likely candidates for the neural generators of short latency vestibular compound action potentials.

  15. The influence of stimulus deviance and novelty on the P300 and novelty P3.

    PubMed

    Goldstein, Abraham; Spencer, Kevin M; Donchin, Emanuel

    2002-11-01

    This study examined the relationship between ERP components elicited by deviant stimuli by disentangling the P300 and Novelty P3 components, using spatiotemporal principal components analysis and a dense electrode array. The three-tone paradigm was used and the pitch attributes of the tones were systematically manipulated so as to map the amplitude of the ERP components on the stimulus context. A comparison was made between the components elicited by events in the three-stimulus, classical oddball, and novelty oddball paradigms. Responses to deviant stimuli consisted of independent and dissociable ERP components in the 400-600-ms time range: A parietal component (P300) that was larger for targets than rare nontargets and was affected by the difficulty of discrimination, a fronto-central component (Novelty P3) that was larger for novel tones and for rare nontargets in the difficult discrimination condition, and an additional anterior negative component responded similarly to all types of deviant stimuli.

  16. Using Stimulus Pairing to Enhance Observational Learning of Peer Initiations for a Child with Autism in a Community Play Group

    ERIC Educational Resources Information Center

    Silla, Vanessa A.; Vesloski, Mary J.

    2008-01-01

    The importance of play in child development and the barriers that individuals with autism face regarding play skills requires us to identify specific interventions which can assist in the development of such skills. Stimulus pairing, which has been documented as a procedure by which an event comes to elicit a response by being paired with an event…

  17. Stimulus conflict triggers behavioral avoidance.

    PubMed

    Dignath, David; Eder, Andreas B

    2015-12-01

    According to a recent extension of the conflict-monitoring theory, conflict between two competing response tendencies is registered as an aversive event and triggers a motivation to avoid the source of conflict. In the present study, we tested this assumption. Over five experiments, we examined whether conflict is associated with an avoidance motivation and whether stimulus conflict or response conflict triggers an avoidance tendency. Participants first performed a color Stroop task. In a subsequent motivation test, participants responded to Stroop stimuli with approach- and avoidance-related lever movements. These results showed that Stroop-conflict stimuli increased the frequency of avoidance responses in a free-choice motivation test, and also increased the speed of avoidance relative to approach responses in a forced-choice test. High and low proportions of response conflict in the Stroop task had no effect on avoidance in the motivation test. Avoidance of conflict was, however, obtained even with new conflict stimuli that had not been presented before in a Stroop task, and when the Stroop task was replaced with an unrelated filler task. Taken together, these results suggest that stimulus conflict is sufficient to trigger avoidance.

  18. Stimulus conflict triggers behavioral avoidance.

    PubMed

    Dignath, David; Eder, Andreas B

    2015-12-01

    According to a recent extension of the conflict-monitoring theory, conflict between two competing response tendencies is registered as an aversive event and triggers a motivation to avoid the source of conflict. In the present study, we tested this assumption. Over five experiments, we examined whether conflict is associated with an avoidance motivation and whether stimulus conflict or response conflict triggers an avoidance tendency. Participants first performed a color Stroop task. In a subsequent motivation test, participants responded to Stroop stimuli with approach- and avoidance-related lever movements. These results showed that Stroop-conflict stimuli increased the frequency of avoidance responses in a free-choice motivation test, and also increased the speed of avoidance relative to approach responses in a forced-choice test. High and low proportions of response conflict in the Stroop task had no effect on avoidance in the motivation test. Avoidance of conflict was, however, obtained even with new conflict stimuli that had not been presented before in a Stroop task, and when the Stroop task was replaced with an unrelated filler task. Taken together, these results suggest that stimulus conflict is sufficient to trigger avoidance. PMID:25931151

  19. Stimulus properties of conspecific behavior

    PubMed Central

    Millard, W. J.

    1979-01-01

    Two experiments identified the conditions in which the behavior of one bird acquired discriminative control of the behavior of a second bird. The schedule-controlled behaviors of the “stimulus” bird were differentially correlated with the components of a multiple schedule according to which the pecking of an “experimental” bird produced food. In Experiment 1, three pairs of pigeons acquired a successive discrimination and two reversals with the conspecific stimuli. Experiment 2 included a control condition in which no systematic relationship existed between the conspecific stimuli and the component schedules. While differential responding during the components of the multiple schedule was again found when the conspecific stimuli were available, differential responding did not occur in the control condition. Test conditions included in the experiments indicated that (a) the differential responding was not dependent on the discriminative properties of reinforcement, (b) the pecking of the stimulus and experimental birds was temporally interrelated, (c) the visual conspecific stimuli were critical to the maintenance of the discrimination, and (d) the observed stimulus control immediately generalized to an unfamiliar conspecific. PMID:16812151

  20. Conditioned suppression of an avoidance response by a stimulus paired with food.

    PubMed

    Davis, H; Kreuter, C

    1972-03-01

    Three food-deprived Long-Evans rats were exposed to a non-discriminated shock avoidance procedure. Superimposed upon this operant avoidance baseline were periodic presentations of a conditioned stimulus that was paired with food, the unconditioned stimulus. These pairings resulted in increases in the rate of shock over that recorded when the conditioned stimulus was not present. A traditional suppression ratio failed to reveal any differential effect of the conditioned stimulus on the overall rate of avoidance responding, although all subjects showed a consistent pattern of pausing and postshock response bursts during presentations of the conditioned stimulus. When food was withheld during a final extinction phase, the conditioned stimulus ceased to occasion increases in shock rates and disruptive postshock response bursts were eliminated. An analysis of conditioned suppression procedures is proposed that stresses not only operant-Pavlovian or appetitive-aversive incompatibility, but also the manner in which the baseline schedule of reinforcement affects operant behavior changes that are elicited by the superimposed Pavlovian procedure.

  1. Do People Take Stimulus Correlations into Account in Visual Search?

    PubMed

    Bhardwaj, Manisha; van den Berg, Ronald; Ma, Wei Ji; Josić, Krešimir

    2016-01-01

    In laboratory visual search experiments, distractors are often statistically independent of each other. However, stimuli in more naturalistic settings are often correlated and rarely independent. Here, we examine whether human observers take stimulus correlations into account in orientation target detection. We find that they do, although probably not optimally. In particular, it seems that low distractor correlations are overestimated. Our results might contribute to bridging the gap between artificial and natural visual search tasks.

  2. Gustatory neural coding in the monkey cortex: stimulus quality.

    PubMed

    Smith-Swintosky, V L; Plata-Salaman, C R; Scott, T R

    1991-10-01

    1. Extracellular action potentials were recorded from 50 single neurons in the insular-opercular cortex of two alert cynomolgus monkeys during gustatory stimulation of the tongue and palate. 2. Sixteen stimuli, including salts, sugars, acids, alkaloids, monosodium glutamate, and aspartame, were chosen to represent a wide range of taste qualities. Concentrations were selected to elicit a moderate gustatory response, as determined by reference to previous electrophysiological data or to the human psychophysical literature. 3. The cortical region over which taste-evoked activity could be recorded included the frontal operculum and anterior insula, an area of approximately 75 mm3. Taste-responsive cells constituted 50 (2.7%) of the 1,863 neurons tested. Nongustatory cells responded to mouth movement (20.7%), somatosensory stimulation of the tongue (9.6%), stimulus approach or anticipation (1.7%), and tongue extension (0.6%). The sensitivities of 64.6% of these cortical neurons could not be identified by our stimulation techniques. 4. Taste cells had low spontaneous activity levels (3.7 +/- 3.0 spikes/s, mean +/- SD) and showed little inhibition. They were moderately broadly tuned, with a mean entropy coefficient of 0.76 +/- 0.17. Excitatory responses were typically not robust. 5. Hierarchical cluster analysis was used to determine whether neurons could be divided into discrete types, as defined by their response profiles to the entire stimulus array. There was an apparent division of response profiles into four general categories, with primary sensitivities to sodium (n = 18), glucose (n = 15), quinine (n = 12), and acid (n = 5). However, these categories were not statistically independent. Therefore the notion of functionally distinct neuron types was not supported by an analysis of the distribution of response profiles. It was the case, however, that neurons in the sodium category could be distinguished from other neurons by their relative specificity. 6. The

  3. Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Squires, N.; Galambos, R.

    1975-01-01

    Short latency (under 10 msec) responses elicited by bursts of white noise were recorded from the scalps of human subjects. Response alterations produced by changes in the noise burst duration (on-time), inter-burst interval (off-time), and onset and offset shapes were analyzed. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise time but was unaffected by changes in fall time. Increases in stimulus duration, and therefore in loudness, resulted in a systematic increase in latency. This was probably due to response recovery processes, since the effect was eliminated with increases in stimulus off-time. The amplitude of wave V was insensitive to changes in signal rise and fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It was concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

  4. Duration discrimination: effects of probability of stimulus presentation.

    PubMed

    Elsmore, T F

    1972-11-01

    Monkeys initiated a stimulus by pressing on the center of three levers and the stimulus terminated independently of behavior 60, 80, 90, or 100 sec later. Presses on the right lever were reinforced with food following the three briefer durations, and presses on the left lever, following the 100-sec duration. Incorrect responses produced a 10-sec timeout. Probability of presenting the 100-sec duration was manipulated in the range from 0.25 to 0.75, with the probabilities of the briefer durations remaining equal and summing to one minus the probability of the 100-sec duration. Percentage of responses on either side lever was functionally related to both the probability of presenting the 100-sec stimulus and to stimulus duration. An analysis of the data based on the theory of signal detection resulted in operating characteristics that were linear when plotted on normal-normal coordinates. The percentage of responses on either lever approximated the optimal values for maximizing reinforcement probability in each condition of the experiment.

  5. Pupillary responses to chromatic stimulus

    NASA Astrophysics Data System (ADS)

    Suaste-Gomez, Ernesto; Rodriguez Guzman, M. C. Ma. Dolores A.; Druzgalski, Christopher

    2000-06-01

    Pupillary responses of the subjects under chromatic visual stimulation were filmed with video-oculography systems (VOG). Specifically, programmable chromatic visual stimuli were displayed on the monitor of a personal computer (PC) and responses tested in several normal subjects and those with ophthalmic pathologic conditions. Visual excitation utilized a reversal stimulus checkerboard pattern. Image processing techniques were applied in order to evaluate the pupil variations due to chromatic stimulation. In particular, the studies determined a relationship between pupillary response (PR) and steady-state retinal sensitivity (photopic vision). Finally, the retinal illuminance in trolands (td), as a product of the pupil area in mm2 and luminance in cd/m2 to full-field chromatic stimulation (FFCS) and checkerboard pattern reversal chromatic stimulation (CPRCS) was determined.

  6. Poverty of the stimulus revisited.

    PubMed

    Berwick, Robert C; Pietroski, Paul; Yankama, Beracah; Chomsky, Noam

    2011-01-01

    A central goal of modern generative grammar has been to discover invariant properties of human languages that reflect "the innate schematism of mind that is applied to the data of experience" and that "might reasonably be attributed to the organism itself as its contribution to the task of the acquisition of knowledge" (Chomsky, 1971). Candidates for such invariances include the structure dependence of grammatical rules, and in particular, certain constraints on question formation. Various "poverty of stimulus" (POS) arguments suggest that these invariances reflect an innate human endowment, as opposed to common experience: Such experience warrants selection of the grammars acquired only if humans assume, a priori, that selectable grammars respect substantive constraints. Recently, several researchers have tried to rebut these POS arguments. In response, we illustrate why POS arguments remain an important source of support for appeal to a priori structure-dependent constraints on the grammars that humans naturally acquire.

  7. Stimulus-evoked outer segment changes in rod photoreceptors

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaohui; Thapa, Damber; Wang, Benquan; Lu, Yiming; Gai, Shaoyan; Yao, Xincheng

    2016-06-01

    Rod-dominated transient retinal phototropism (TRP) has been recently observed in freshly isolated mouse and frog retinas. Comparative confocal microscopy and optical coherence tomography revealed that the TRP was predominantly elicited from the rod outer segment (OS). However, the biophysical mechanism of rod OS dynamics is still unknown. Mouse and frog retinal slices, which displayed a cross-section of retinal photoreceptors and other functional layers, were used to test the effect of light stimulation on rod OSs. Time-lapse microscopy revealed stimulus-evoked conformational changes of rod OSs. In the center of the stimulated region, the length of the rod OS shrunk, while in the peripheral region, the rod OS swung toward the center region. Our experimental observation and theoretical analysis suggest that the TRP may reflect unbalanced rod disc-shape changes due to localized visible light stimulation.

  8. Stimulus Coding Rules for Perceptual Learning

    PubMed Central

    Klein, Stanley A; Levi, Dennis M; Yu, Cong

    2008-01-01

    Perceptual learning of visual features occurs when multiple stimuli are presented in a fixed sequence (temporal patterning), but not when they are presented in random order (roving). This points to the need for proper stimulus coding in order for learning of multiple stimuli to occur. We examined the stimulus coding rules for learning with multiple stimuli. Our results demonstrate that: (1) stimulus rhythm is necessary for temporal patterning to take effect during practice; (2) learning consolidation is subject to disruption by roving up to 4 h after each practice session; (3) importantly, after completion of temporal-patterned learning, performance is undisrupted by extended roving training; (4) roving is ineffective if each stimulus is presented for five or more consecutive trials; and (5) roving is also ineffective if each stimulus has a distinct identity. We propose that for multi-stimulus learning to occur, the brain needs to conceptually “tag” each stimulus, in order to switch attention to the appropriate perceptual template. Stimulus temporal patterning assists in tagging stimuli and switching attention through its rhythmic stimulus sequence. PMID:18707195

  9. Optimism

    PubMed Central

    Carver, Charles S.; Scheier, Michael F.; Segerstrom, Suzanne C.

    2010-01-01

    Optimism is an individual difference variable that reflects the extent to which people hold generalized favorable expectancies for their future. Higher levels of optimism have been related prospectively to better subjective well-being in times of adversity or difficulty (i.e., controlling for previous well-being). Consistent with such findings, optimism has been linked to higher levels of engagement coping and lower levels of avoidance, or disengagement, coping. There is evidence that optimism is associated with taking proactive steps to protect one's health, whereas pessimism is associated with health-damaging behaviors. Consistent with such findings, optimism is also related to indicators of better physical health. The energetic, task-focused approach that optimists take to goals also relates to benefits in the socioeconomic world. Some evidence suggests that optimism relates to more persistence in educational efforts and to higher later income. Optimists also appear to fare better than pessimists in relationships. Although there are instances in which optimism fails to convey an advantage, and instances in which it may convey a disadvantage, those instances are relatively rare. In sum, the behavioral patterns of optimists appear to provide models of living for others to learn from. PMID:20170998

  10. Optimization of retinotopy constrained source estimation constrained by prior

    PubMed Central

    Hagler, Donald J.

    2015-01-01

    Studying how the timing and amplitude of visual evoked responses (VERs) vary between visual areas is important for understanding visual processing but is complicated by difficulties in reliably estimating VERs in individual visual areas using non-invasive brain measurements. Retinotopy constrained source estimation (RCSE) addresses this challenge by using multiple, retinotopically-mapped stimulus locations to simultaneously constrain estimates of VERs in visual areas V1, V2, and V3, taking advantage of the spatial precision of fMRI retinotopy and the temporal resolution of magnetoencephalography (MEG) or electroencephalography (EEG). Nonlinear optimization of dipole locations, guided by a group-constrained RCSE solution as a prior, improved the robustness of RCSE. This approach facilitated the analysis of differences in timing and amplitude of VERs between V1, V2, and V3, elicited by stimuli with varying luminance contrast in a sample of eight adult humans. The V1 peak response was 37% larger than that of V2 and 74% larger than that of V3, and also ~10–20 msec earlier. Normalized contrast response functions were nearly identical for the three areas. Results without dipole optimization, or with other nonlinear methods not constrained by prior estimates were similar but suffered from greater between-subject variability. The increased reliability of estimates offered by this approach may be particularly valuable when using a smaller number of stimulus locations, enabling a greater variety of stimulus and task manipulations. PMID:23868690

  11. Utility-based early modulation of processing distracting stimulus information.

    PubMed

    Wendt, Mike; Luna-Rodriguez, Aquiles; Jacobsen, Thomas

    2014-12-10

    Humans are selective information processors who efficiently prevent goal-inappropriate stimulus information to gain control over their actions. Nonetheless, stimuli, which are both unnecessary for solving a current task and liable to cue an incorrect response (i.e., "distractors"), frequently modulate task performance, even when consistently paired with a physical feature that makes them easily discernible from target stimuli. Current models of cognitive control assume adjustment of the processing of distractor information based on the overall distractor utility (e.g., predictive value regarding the appropriate response, likelihood to elicit conflict with target processing). Although studies on distractor interference have supported the notion of utility-based processing adjustment, previous evidence is inconclusive regarding the specificity of this adjustment for distractor information and the stage(s) of processing affected. To assess the processing of distractors during sensory-perceptual phases we applied EEG recording in a stimulus identification task, involving successive distractor-target presentation, and manipulated the overall distractor utility. Behavioral measures replicated previously found utility modulations of distractor interference. Crucially, distractor-evoked visual potentials (i.e., posterior N1) were more pronounced in high-utility than low-utility conditions. This effect generalized to distractors unrelated to the utility manipulation, providing evidence for item-unspecific adjustment of early distractor processing to the experienced utility of distractor information.

  12. Stimulus appraisal modulates cardiac reactivity to briefly presented mutilation pictures.

    PubMed

    Mocaiber, Izabela; Perakakis, Pandelis; Pereira, Mirtes Garcia; Pinheiro, Walter Machado; Volchan, Eliane; de Oliveira, Letícia; Vila, Jaime

    2011-09-01

    Emotional reactions to threatening situations can be either advantageous for human adaptation or unfavorable for physical and mental health if sustained over prolonged periods of time. These contrasting effects mostly depend on the individual's capacity for emotion regulation. It has been shown, for example, that changing appraisal can alter the course of emotional processing. In the present study, the influence of stimulus appraisal over cardiac reactivity to briefly presented (200ms) mutilation pictures was tested in the context of an affective classification task. Heart rate and reaction time of twenty-four undergraduate students were monitored during the presentation of pictures (neutral or mutilated bodies) in successive blocks. In one condition (real), participants were told that the pictures depicted real events. In the other condition (fictitious), they were told that the pictures were taken from movie scenes. As expected, the results showed a more pronounced bradycardia to mutilation pictures, in comparison to neural pictures, in the real context. In the fictitious context, a significant attenuation of the emotional modulation (defensive bradycardia) was observed. However, this attenuation seemed to be transient because it was only observed in the first presentation block of the fictitious context. Reaction time to classify mutilation pictures, compared to neutral pictures, was slower in both contexts, reflecting the privileged processing of emotionally laden material. The present findings show that even briefly presented mutilation pictures elicit a differential cardiac reactivity and modulate behavioral performance. Importantly, changing stimulus appraisal attenuates the emotional modulation of cardiac reactivity (defensive bradycardia).

  13. Neural correlates of stimulus spatial frequency-dependent contrast detection

    PubMed Central

    Meng, Jianjun; Liu, Ruilong; Wang, Ke; Hua, Tianmiao; Lu, Zhong-Lin; Xi, Minmin

    2016-01-01

    Psychophysical studies on human and non-human vertebrate species have shown that visual contrast sensitivity function (CSF) peaks at a certain stimulus spatial frequency and declines in both lower and higher spatial frequencies. The underlying neural substrate and mechanisms remain in debate. Here, we investigated the role of primary visual cortex (V1: area 17) in spatial frequency-dependent contrast detection in cats. Perceptual CSFs of three cats were measured using a two-alternative forced choice task. The responses of V1 neurons to their optimal visual stimuli in a range of luminance contrast levels (from 0 to 1.0) were recorded subsequently using in vivo extracellular single-unit recording techniques. The contrast sensitivity of each neuron was determined. The neuronal CSF for each cat was constructed from the mean contrast sensitivity of neurons with different preferred stimulus spatial frequencies. Results (1) The perceptual and neuronal CSFs of each of the three cats exhibited a similar shape with peak amplitude near 0.4 c/deg. (2) The neuronal CSF of each cat was highly correlated with its perceptual CSF. (3) V1 neurons with different preferred stimulus spatial frequencies had different contrast gains. Conclusion (1) Contrast detection of visual stimuli with different spatial frequencies may likely involve population coding of V1 neurons with different preferred stimulus spatial frequencies. (2) Difference in contrast-gain may underlie the observed contrast sensitivity variation of V1 neurons with different preferred stimulus spatial frequencies, possibly from either evolution or postnatal visual experiences. PMID:23314692

  14. Investigation of Stimulus-Response Compatibility Using a Startling Acoustic Stimulus

    ERIC Educational Resources Information Center

    Maslovat, Dana; Carlsen, Anthony N.; Franks, Ian M.

    2012-01-01

    We investigated the processes underlying stimulus-response compatibility by using a lateralized auditory stimulus in a simple and choice reaction time (RT) paradigm. Participants were asked to make either a left or right key lift in response to either a control (80dB) or startling (124dB) stimulus presented to either the left ear, right ear, or…

  15. An Evaluation of the Number of Presentations of Target Sounds during Stimulus-Stimulus Pairing Trials

    ERIC Educational Resources Information Center

    Miliotis, Adriane; Sidener, Tina M.; Reeve, Kenneth F.; Carbone, Vincent; Sidener, David W.; Rader, Lisa; Delmolino, Lara

    2012-01-01

    Stimulus-stimulus pairing (SSP) of vocalizations pairs the speech of others with the delivery of highly preferred items. The goal of this procedure is to produce a temporary increase in vocalizations, thus creating a larger variety of sounds that can subsequently be brought under appropriate stimulus control (Esch, Carr, & Grow, 2009). In this…

  16. Neural heterogeneities and stimulus properties affect burst coding in vivo.

    PubMed

    Avila-Akerberg, O; Krahe, R; Chacron, M J

    2010-06-16

    Many neurons tend to fire clusters of action potentials called bursts followed by quiescence in response to sensory input. While the mechanisms that underlie burst firing are generally well understood in vitro, the functional role of these bursts in generating behavioral responses to sensory input in vivo are less clear. Pyramidal cells within the electrosensory lateral line lobe (ELL) of weakly electric fish offer an attractive model system for studying the coding properties of burst firing, because the anatomy and physiology of the electrosensory circuitry are well understood, and the burst mechanism of ELL pyramidal cells has been thoroughly characterized in vitro. We investigated the coding properties of bursts generated by these cells in vivo in response to mimics of behaviorally relevant sensory input. We found that heterogeneities within the pyramidal cell population had quantitative but not qualitative effects on burst coding for the low frequency components of broadband time varying input. Moreover, spatially localized stimuli mimicking, for example, prey tended to elicit more bursts than spatially global stimuli mimicking conspecific-related stimuli. We also found small but significant correlations between burst attributes such as the number of spikes per burst or the interspike interval during the burst and stimulus attributes such as stimulus amplitude or slope. These correlations were much weaker in magnitude than those observed in vitro. More surprisingly, our results show that correlations between burst and stimulus attributes actually decreased in magnitude when we used low frequency stimuli that are expected to promote burst firing. We propose that this discrepancy is attributable to differences between ELL pyramidal cell burst firing under in vivo and in vitro conditions.

  17. Stimulus Probability Effects in Absolute Identification

    ERIC Educational Resources Information Center

    Kent, Christopher; Lamberts, Koen

    2016-01-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of…

  18. Some determinants of inhibitory stimulus control.

    PubMed

    Weisman, R G

    1969-05-01

    Interspersed reinforcement and extinction during discrimination learning generate a U-shaped gradient of inhibition about the stimulus correlated with extinction. The present work showed that extinction is not a necessary determinant of inhibitory stimulus control. In Exp. I, a reduction in the rate of reinforcement, through a shift from a multiple variable-interval 1-min variable-interval 1-min schedule to a multiple variable-interval 1-min variable-interval 5-min schedule, resulted in a post-discrimination line orientation gradient of inhibition about the stimulus correlated with the variable-interval 5-min schedule. In Exp. II, the rates of reinforcement, correlated with a pair of stimuli, were held constant during a shift from a multiple variable-interval 1-min variable-interval 1-min schedule to a multiple variable-interval 1-min differential-reinforcement-of-low-rate schedule. Inhibitory stimulus control about the stimulus correlated with the differential reinforcement of low rate was obtained. In both experiments, a reduction in the rate of responding during one stimulus and behavioral contrast during the other stimulus preceded the observation of inhibitory stimulus control.

  19. Stimulus Intensity and the Perception of Duration

    ERIC Educational Resources Information Center

    Matthews, William J.; Stewart, Neil; Wearden, John H.

    2011-01-01

    This article explores the widely reported finding that the subjective duration of a stimulus is positively related to its magnitude. In Experiments 1 and 2 we show that, for both auditory and visual stimuli, the effect of stimulus magnitude on the perception of duration depends upon the background: Against a high intensity background, weak stimuli…

  20. Why Additional Presentations Help Identify a Stimulus

    ERIC Educational Resources Information Center

    Guest, Duncan; Kent, Christopher; Adelman, James S.

    2010-01-01

    Nosofsky (1983) reported that additional stimulus presentations within a trial increase discriminability in absolute identification, suggesting that each presentation creates an independent stimulus representation, but it remains unclear whether exposure duration or the formation of independent representations improves discrimination in such…

  1. Quantitative and methodological aspects of stimulus equivalence.

    PubMed

    O'mara, H

    1991-01-01

    The number of different ways of linking stimuli in the training phase of a conditional discrimination procedure designed to teach equivalence relations has hitherto been underestimated. An algorithm from graph theory that produces the correct number of such different ways is given. The establishment of equivalence relations requires transitive stimulus control. A misconception in a previous analysis of the conditions necessary for demonstrating transitive stimulus control is indicated. This misconception concerns responding in an unreinforced test trial to a negative rather than a positive comparison stimulus. Such behavior cannot be attributed to discriminative control by degree of association with reinforcement if the negative comparison stimulus has been less associated with reinforcement than the positive comparison stimulus in an antecedent training phase.

  2. Emotion Elicitation: A Comparison of Pictures and Films

    PubMed Central

    Uhrig, Meike K.; Trautmann, Nadine; Baumgärtner, Ulf; Treede, Rolf-Detlef; Henrich, Florian; Hiller, Wolfgang; Marschall, Susanne

    2016-01-01

    Pictures and film clips are widely used and accepted stimuli to elicit emotions. Based on theoretical arguments it is often assumed that the emotional effects of films exceed those of pictures, but to date this assumption has not been investigated directly. The aim of the present study was to compare pictures and films in terms of their capacity to induce emotions verified by means of explicit measures. Stimuli were (a) single pictures presented for 6 s, (b) a set of three consecutive pictures with emotionally congruent contents presented for 2 s each, (c) short film clips with a duration of 6 s. A total of 144 participants rated their emotion and arousal states following stimulus presentation. Repeated-measures ANOVAs revealed that the film clips and 3-picture version were as effective as the classical 1-picture method to elicit positive emotions, however, modulation toward positive valence was little. Modulation toward negative valence was more effective in general. Film clips were less effective than pictorial stimuli in producing the corresponding emotion states (all p < 0.001) and were less arousing (all p ≤ 0.02). Possible reasons for these unexpected results are discussed. PMID:26925007

  3. The stimulus integration area for horizontal vergence.

    PubMed

    Allison, Robert S; Howard, Ian P; Fang, Xueping

    2004-06-01

    Over what region of space are horizontal disparities integrated to form the stimulus for vergence? The vergence system might be expected to respond to disparities within a small area of interest to bring them into the range of precise stereoscopic processing. However, the literature suggests that disparities are integrated over a fairly large parafoveal area. We report the results of six experiments designed to explore the spatial characteristics of the stimulus for vergence. Binocular eye movements were recorded using magnetic search coils. Each dichoptic display consisted of a central target stimulus that the subject attempted to fuse, and a competing stimulus with conflicting disparity. In some conditions the target was stationary, providing a fixation stimulus. In other conditions, the disparity of the target changed to provide a vergence-tracking stimulus. The target and competing stimulus were combined in a variety of conditions including those in which (1) a transparent textured-disc target was superimposed on a competing textured background, (2) a textured-disc target filled the centre of a competing annular background, and (3) a small target was presented within the centre of a competing annular background of various inner diameters. In some conditions the target and competing stimulus were separated in stereoscopic depth. The results are consistent with a disparity integration area with a diameter of about 5 degrees. Stimuli beyond this integration area can drive vergence in their own right, but they do not appear to be summed or averaged with a central stimulus to form a combined disparity signal. A competing stimulus had less effect on vergence when separated from the target by a disparity pedestal. As a result, we propose that it may be more useful to think in terms of an integration volume for vergence rather than a two-dimensional retinal integration area. PMID:14985895

  4. Stimulus-dependency and mechanisms of surround modulation in cortical area MT

    PubMed Central

    Huang, Xin; Albright, Thomas D.; Stoner, Gene R.

    2009-01-01

    The perceptual interpretation of a given visual feature depends on the surrounding context. To explore the neural mechanisms underlying such contextual interactions in the motion domain, we studied responses of neurons in cortical area MT of macaque monkeys while presenting a variety of center-surround stimuli that stimulated both the classical receptive visual field (CRF) and the receptive field surround. In human psychophysical experiments, the perceptual impact of the surround stimulus on the center stimulus varied from motion capture (“integration”) to motion contrast (“segmentation”). In our neurophysiological experiments, the directional tuning of surround modulation with these stimuli ranged from antagonistic (consistent with motion contrast) to integrative (consistent with motion capture) and agreed qualitatively with perception under some but not all conditions. Most strikingly, for a stimulus that elicited perceptual motion contrast, surround modulation was integrative if the CRF stimulus was ambiguous due to the aperture problem. In addition, we found that surround modulation was linked to response magnitude: stimuli eliciting the largest responses yielded the strongest antagonism and those eliciting the smallest responses yielded the strongest integration. We developed a neural network model that accounts for this finding as well as a previous finding that surround suppression in area MT is contrast-dependent. Our findings suggest that changes in MT surround modulation result from shifts in the balance between directionally-tuned excitation and inhibition mediated by changes in input strength. We speculate that input strength is, in turn, linked with the ambiguity of the motion present within the CRF. PMID:19091978

  5. On the development of stimulus control.

    PubMed

    Heinemann, E G; Avin, E

    1973-09-01

    Pigeons were trained to peck one key when presented with white noise at any of five intensities lower than a reference intensity, and to peck another key when presented with white noise at any of five intensities greater than the reference intensity. The shape of the stimulus control curves (proportion of responses to one key versus stimulus intensity) changed from a horizontal line at the beginning of training to the sigmoid form of typical psychometric functions at the end of training. The development of stimulus control is described in terms of a model based on the theory of signal recognition and a concept of attention.

  6. Continuous- and Discrete-Time Stimulus Sequences for High Stimulus Rate Paradigm in Evoked Potential Studies

    PubMed Central

    Wang, Tao; Huang, Jiang-hua; Lin, Lin

    2013-01-01

    To obtain reliable transient auditory evoked potentials (AEPs) from EEGs recorded using high stimulus rate (HSR) paradigm, it is critical to design the stimulus sequences of appropriate frequency properties. Traditionally, the individual stimulus events in a stimulus sequence occur only at discrete time points dependent on the sampling frequency of the recording system and the duration of stimulus sequence. This dependency likely causes the implementation of suboptimal stimulus sequences, sacrificing the reliability of resulting AEPs. In this paper, we explicate the use of continuous-time stimulus sequence for HSR paradigm, which is independent of the discrete electroencephalogram (EEG) recording system. We employ simulation studies to examine the applicability of the continuous-time stimulus sequences and the impacts of sampling frequency on AEPs in traditional studies using discrete-time design. Results from these studies show that the continuous-time sequences can offer better frequency properties and improve the reliability of recovered AEPs. Furthermore, we find that the errors in the recovered AEPs depend critically on the sampling frequencies of experimental systems, and their relationship can be fitted using a reciprocal function. As such, our study contributes to the literature by demonstrating the applicability and advantages of continuous-time stimulus sequences for HSR paradigm and by revealing the relationship between the reliability of AEPs and sampling frequencies of the experimental systems when discrete-time stimulus sequences are used in traditional manner for the HSR paradigm. PMID:23606900

  7. Cycloheximide: No Ordinary Bitter Stimulus

    PubMed Central

    Hettinger, Thomas P.; Formaker, Bradley K.; Frank, Marion E.

    2007-01-01

    Cycloheximide (CyX), a toxic antibiotic with a unique chemical structure generated by the actinomycete, Streptomyces griseus, has emerged as a primary focus of studies on mammalian bitter taste. Rats and mice avoid it at concentrations well below the thresholds for most bitter stimuli and T2R G-protein-coupled receptors specific for CyX with appropriate sensitivity are identified for those species. Like mouse and rat, golden hamsters, Mesocricetus auratus, also detected and rejected micromolar levels of CyX, although 1 mM CyX failed to activate the hamster chorda tympani nerve. Hamsters showed an initial tolerance for 500 μM CyX, but after that, avoidance of CyX dramatically increased, plasticity not reported for rat or mouse. As the hamster lineage branches well before division of the mouse-rat lineage in evolutionary time, differences between hamster and mouse-rat reactions to CyX are not surprising. Furthermore, unlike hamster LiCl-induced learned aversions, the induced CyX aversion neither specifically nor robustly generalized to other non-ionic bitter stimuli; and unlike adverse reactions to other chemosensory stimuli, aversions to CyX were not mollified by adding a sweetener. Thus, CyX is unlike other bitter stimuli. The gene for the high-affinity CyX receptor is a member of a cluster of 5 orthologous T2R genes that are likely rodent specific; this “CyX clade” is found in the mouse, rat and probably hamster, but not in the human or rabbit genome. The rodent CyX-T2R interaction may be one of multiple lineage-specific stimulus-receptor interactions reflecting a response to a particular environmental toxin. The combination of T2R multiplicity, species divergence and gene duplication results in diverse ligands for multiple species-specific T2R receptors, which confounds definition of ‘bitter’ stimuli across species. PMID:17400304

  8. Stimulus Suffix Effects in Dichotic Memory

    ERIC Educational Resources Information Center

    Parkinson, Stanley R.; Hubbard, Lora L.

    1974-01-01

    in the present dichotic memory research, the addition of either a monaural stimulus suffix on the unattended ear or a binaural suffix was shown to selectively impair unattended-ear performance. (Editor)

  9. The basis of superstitious behavior: chance contingency, stimulus substitution, or appetitive behavior?

    PubMed Central

    Timberlake, W; Lucas, G A

    1985-01-01

    This research examined three explanations for the "superstitious" behavior of pigeons under frequent fixed-time delivery of food: accidental response-reward contingency, stimulus substitution, and elicited species-typical appetitive behavior. The behavior observed in these studies consisted of occasional postfood locomotion away from the food hopper, and a predominant pattern of activity directed toward the hopper wall (wall-directed behavior), including approaching, stepping side to side, scratching with the feet, bumping with the breast, pendulum movements of the extended neck, and head bobbing, though not pecking. The consistency of these behavior patterns argued against explanation by accidental response contingencies, and the complexity of behavior was incompatible with the classic stimulus-substitution account. These studies also showed that: (1) response contingencies and prior stimulus experience can modify wall-directed behavior, but within definable limits; (2) pecking sometimes can be obtained in birds of specific strains, and by providing extended training; (3) placing the hopper in the floor at the center of a large chamber replaces wall-directed behavior with circling in a manner that resembles ground foraging for food. We conclude that superstitious behavior under periodic delivery of food probably develops from components of species-typical patterns of appetitive behavior related to feeding. These patterns are elicited by a combination of frequent food presentations and the supporting stimuli present in the environment. PMID:4086972

  10. Observing behavior and atypically restricted stimulus control.

    PubMed

    Dube, William V; Dickson, Chata A; Balsamo, Lyn M; O'Donnell, Kristin Lombard; Tomanari, Gerson Y; Farren, Kevin M; Wheeler, Emily E; McIlvane, William J

    2010-11-01

    Restricted stimulus control refers to discrimination learning with atypical limitations in the range of controlling stimuli or stimulus features. In the study reported here, 4 normally capable individuals and 10 individuals with intellectual disabilities (ID) performed two-sample delayed matching to sample. Sample-stimulus observing was recorded with an eye-tracking apparatus. High accuracy scores indicated stimulus control by both sample stimuli for the 4 nondisabled participants and 4 participants with ID, and eye tracking data showed reliable observing of all stimuli. Intermediate accuracy scores indicated restricted stimulus control for the remaining 6 participants. Their eye-tracking data showed that errors were related to failures to observe sample stimuli and relatively brief observing durations. Five of these participants were then given interventions designed to improve observing behavior. For 4 participants, the interventions resulted initially in elimination of observing failures, increased observing durations, and increased accuracy. For 2 of these participants, contingencies sufficient to maintain adequate observing were not always sufficient to maintain high accuracy; subsequent procedure modifications restored it, however. For the 5th participant, initial improvements in observing were not accompanied by improved accuracy, an apparent instance of observing without attending; accuracy improved only after an additional intervention that imposed contingencies on observing behavior. Thus, interventions that control observing behavior seem necessary but may not always be sufficient for the remediation of restricted stimulus control.

  11. Extinguished operant responding shows stimulus specificity.

    PubMed

    McSweeney, Frances K; Murphy, Eric S; Kowal, Benjamin P

    2004-03-31

    The experiment tested for stimulus specificity in extinguished operant responding. Eight pigeons pecked keys for food reinforcers delivered by a variable interval (VI) 60-s schedule. The key was illuminated with red light during some sessions and white light during others. Then, responding was placed on extinction. During some sessions of extinction, the color of the key light remained constant throughout the session (red or white). During other sessions the color changed at 30 min into the session (red to white or white to red). Response rate increased after the change of key color in extinction. If it is assumed that key color is part of the stimulus to which subjects habituate, then these results are consistent with McSweeney and Swindell's [J. Gen. Psychol. 129 (2002) 364] suggestion that responding declines in extinction partly because subjects habituate to the stimuli that support conditioned responding. Habituation is relatively specific to the exact nature of the stimulus presented. Therefore, changes in the stimulus violate stimulus specificity and restore habituated responding. The results are also consistent with other theories that attribute extinction to a reduction of stimulus control [e.g., Psychol. Bull. 114 (1993) 80; J. Exp. Psychol.: Anim. Behav. Process. 16 (1990) 235], but considerations such as parsimony and testability favor the habituation hypothesis over these theories.

  12. Occlusion for stimulus deprivation amblyopia

    PubMed Central

    Antonio-Santos, Aileen; Vedula, Satyanarayana S; Hatt, Sarah R; Powell, Christine

    2014-01-01

    Background Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the passage of light secondary to a condition such as cataract. The obstruction prevents formation of a clear image on the retina. SDA can be resistant to treatment, leading to poor visual prognosis. SDA probably constitutes less than 3% of all amblyopia cases, although precise estimates of prevalence are unknown. In developed countries, most patients present under the age of one year; in less developed parts of the world patients are likely to be older at the time of presentation. The mainstay of treatment is removal of the cataract and then occlusion of the better-seeing eye, but regimens vary, can be difficult to execute, and traditionally are believed to lead to disappointing results. Objectives Our objective was to evaluate the effectiveness of occlusion therapy for SDA in an attempt to establish realistic treatment outcomes. Where data were available, we also planned to examine evidence of any dose response effect and to assess the effect of the duration, severity, and causative factor on the size and direction of the treatment effect. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to October 2013), EMBASE (January 1980 to October 2013), the Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2013), PubMed (January 1946 to October 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 October 2013. Selection criteria We planned

  13. Stimulus content and the neural correlates of source memory.

    PubMed

    Duarte, Audrey; Henson, Richard N; Graham, Kim S

    2011-02-10

    It has been suggested that several regions of the brain, including subregions of the medial temporal lobe (MTL) and the posterior parietal cortex, contribute to source memory success in a material-general manner, with most models highlighting the importance of memory process rather than material type. For the MTL in particular, however, increasing evidence suggests that MTL subregions may be specialized for processing different materials, raising the possibility that source memory-related activity may be material-sensitive. Previous fMRI studies have not directly compared source memory activity for different categories of stimuli, and it remains unclear whether source memory effects, in the MTL or elsewhere, are influenced by material. To investigate this issue, young participants were scanned during study while they made semantic judgments about words, pictures of objects and scenes, and during test when they retrieved the context (source) in which these items were studied. Several regions, including the hippocampi, medial and lateral parietal cortex, exhibited source memory effects common to words, objects and scenes, at both study and test. Material-dependent source memory effects were also identified in the left posterior inferior frontal and left perirhinal cortex for words and objects, respectively, at study but not test. These results offer direct support for the hypothesis that the MTL and posterior parietal cortex make material-general contributions to recollection. These results also point to a dissociation between encoding and retrieval with regard to the influence of material on the neural correlates of source memory accuracy, supporting the idea that a relatively small proportion of the activity elicited by a stimulus during encoding is incorporated into an episodic memory representation of the stimulus.

  14. Stimulus-induced and state-dependent sustained gamma activity is tightly coupled to the hemodynamic response in humans.

    PubMed

    Koch, Stefan P; Werner, Peter; Steinbrink, Jens; Fries, Pascal; Obrig, Hellmuth

    2009-11-01

    A prompt behavioral response to a stimulus depends both on the salience of the stimulus as well as the subject's preparedness. Thus, both stimulus properties and cognitive factors, such as attention, may determine the strength of neuronal synchronization in the gamma range. For a comprehensive investigation of stimulus-response processing through noninvasive imaging, it is, however, a crucial issue whether both kinds of gamma modulation elicit a hemodynamic response. Here, we show that, in the human visual cortex, stimulus strength and internal state modulate sustained gamma activity and hemodynamic response in close correspondence. When participants reported velocity changes of gratings varying in contrast, gamma activity (35-70 Hz) increased systematically with contrast. For stimuli of constant contrast, the amplitude of gamma activity before the behaviorally relevant velocity change was inversely correlated to the behavioral response latency. This indicates that gamma activity also reflects an overall attentive state. For both sources of variance, gamma activity was tightly coupled to the hemodynamic response measured through optical topography. Because of the close relationship between high-frequency neuronal activity and the hemodynamic signal, we conclude that both stimulus-induced and state-dependent gamma activity trigger a metabolic demand and are amenable to vascular-based imaging. PMID:19890006

  15. Stimulus-driven reorienting in the ventral frontoparietal attention network: the role of emotional content

    PubMed Central

    Frank, David W.; Sabatinelli, Dean

    2012-01-01

    Activity in the human temporoparietal junction (TPJ) and inferior frontal gyrus (IFG) is hypothesized to underlie stimulus-driven, or “bottom-up” attention reorienting. Demanding tasks require focused attention, and as task difficulty increases, activity suppression in the ventral network correlates positively with task performance, an effect thought to reflect the gating of irrelevant cues. However, activation in these structures is elicited by a range of stimulus features and task demands that vary across multiple characteristics, complicating the interpretation of the functional role of this pathway. Consideration of several current studies suggests that, in addition to task difficulty, the motivational relevance or emotional intensity of distractor stimuli may supersede ongoing task priority, and evoke ventral network activation. Support for this possibility is offered from a review of recent reports, and the import of this perspective for models of attention reorienting is discussed. PMID:22557960

  16. 8-OH-DPAT suppresses vomiting in the cat elicited by motion, cisplatin or xylazine

    NASA Technical Reports Server (NTRS)

    Lucot, James B.; Crampton, George H.

    1989-01-01

    Vomiting was suppressed in cats pretreated with 8-OH-DPAT and then challenged with an emetic stimulus; motion, xylazine or cisplatin. The antiemetic effect is likely due to stimulation of postsynaptic serotonin-1A receptors. The most parsimonious explanation is that it acts at a convergent structure, presumably at or near the vomiting center. If so, 8-OH-DPAT may block emesis elicited by virtually any other stimulus. A supplementary experiment revealed that lorazepam suppressed motion sickness at a dose that produced ataxia, but did not suppress xylazine-induced emesis. These results do not support the possibility that the antiemetic effects of 8-OH-DPAT were the result of anxiolytic activity.

  17. A negative stimulus movement effect in pigeons.

    PubMed

    Daniel, Thomas A; Katz, Jeffrey S

    2016-09-01

    Rhesus monkeys and humans perform more accurately in matching-to-sample tasks when the sample stimulus moves through space (Washburn et al., 1989; Washburn, 1993). This Stimulus Movement Effect (SME) is believed to be due to movement increasing attention toward the sample stimulus, creating an easier discrimination between the sample and choice stimuli. To date, there is no evidence for this phenomenon in a non-mammalian species. In the current study, we investigate the possibility of an SME in an avian species. Across three experiments, pigeons were tested with moving and stationary sample stimuli in a non-matching- to-sample task. The area and velocity by which the sample stimulus traveled was manipulated but no advantage for moving over stationary sample trials was found within or across sessions. Even when a delay condition was implemented, there was no advantage for moving sample trials. Contrary to the results found in humans and monkeys, pigeons performed better when the sample was stationary, a negative SME, and no evidence was found that stimulus movement increases discrimination performance.

  18. Stimulus-Stimulus Pairing and Subsequent Mand Acquisition of Children with Various Levels of Verbal Repertoires

    ERIC Educational Resources Information Center

    Yoon, Soyoung; Feliciano, Gina M.

    2007-01-01

    Effects of a stimulus-stimulus pairing procedure on the subsequent acquisition of mand operants were investigated. An attempt was made to shape novel sounds that emerged through the pairing procedure into a mand. Six children, aged two to five years, with moderate to severe language and communication delays, participated. Two conditions were used…

  19. Sample Stimulus Control Shaping and Restricted Stimulus Control in Capuchin Monkeys: A Methodological Note

    ERIC Educational Resources Information Center

    Brino, Ana Leda F., Barros, Romariz S., Galvao, Ol; Garotti, M.; Da Cruz, Ilara R. N.; Santos, Jose R.; Dube, William V.; McIlvane, William J.

    2011-01-01

    This paper reports use of sample stimulus control shaping procedures to teach arbitrary matching-to-sample to 2 capuchin monkeys ("Cebus apella"). The procedures started with identity matching-to-sample. During shaping, stimulus features of the sample were altered gradually, rendering samples and comparisons increasingly physically dissimilar. The…

  20. Emergent Stimulus Relations Depend on Stimulus Correlation and Not on Reinforcement Contingencies

    ERIC Educational Resources Information Center

    Minster, Sara Tepaeru; Elliffe, Douglas; Muthukumaraswamy, Suresh D.

    2011-01-01

    We aimed to investigate whether novel stimulus relations would emerge from stimulus correlations when those relations explicitly conflicted with reinforced relations. In a symbolic matching-to-sample task using kanji characters as stimuli, we arranged class-specific incorrect comparison stimuli in each of three classes. After presenting either Ax…

  1. Stimulus probability effects in absolute identification.

    PubMed

    Kent, Christopher; Lamberts, Koen

    2016-05-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of presentation probability on both proportion correct and response times. The effects were moderated by the ubiquitous stimulus position effect. The accuracy and response time data were predicted by an exemplar-based model of perceptual cognition (Kent & Lamberts, 2005). The bow in discriminability was also attenuated when presentation probability for middle items was relatively high, an effect that will constrain future model development. The study provides evidence for item-specific learning in absolute identification. Implications for other theories of absolute identification are discussed. (PsycINFO Database Record

  2. Vertical displacement threshold sensitivity along the horizontal meridian as a function of stimulus rate, duration, and length

    NASA Technical Reports Server (NTRS)

    Haines, Richard F.; Kiefel, Steven M.

    1988-01-01

    Four independent variables of visual perception during binocular viewing were studied. In 24 observers, the vertical displacement threshold (DT) sensitivity along the horizontal meridian was determined as a function of the rate, duration, and length of the stimulus. It was found that the DT increases with an increased angular separation of the stimulus image from the fovea (i.e., the stimulus must move farther in order to be correctly discriminated as having moved). In addition, it was found that the sensitivity to the stimulus displacement increases with increasing of the stimulus length, duration, and/or angular rate. These findings are related to the design optimization of dynamic attitude displays and symbology for aircraft.

  3. Learning bundles of stimuli renders stimulus order as a cue, not a confound.

    PubMed

    Qian, Ting; Aslin, Richard N

    2014-10-01

    The order in which stimuli are presented in an experiment has long been recognized to influence behavior. Previous accounts have often attributed the effect of stimulus order to the mechanisms with which people process information. We propose that stimulus order influences cognition because it is an important cue for learning the underlying structure of a task environment. In particular, stimulus order can be used to infer a "stimulus bundle"--a sequence of consecutive stimuli that share the same underlying latent cluster. We describe a clustering model that successfully explains the perception of streak shooting in basketball games, along with two other cognitive phenomena, as the outcome of finding the statistically optimal bundle representation. We argue that the perspective of viewing stimulus order as a cue may hold the key to explaining behaviors that seemingly deviate from normative theories of cognition and that in task domains where the assumption of stimulus bundles is intuitively appropriate, it can improve the explanatory power of existing models.

  4. Contributions to drug abuse research of Steven R. Goldberg's behavioral analysis of stimulus-stimulus contingencies.

    PubMed

    Katz, Jonathan L

    2016-05-01

    By the mid-1960s, the concept that drugs can function as reinforcing stimuli through response-reinforcer contingencies had created a paradigm shift in drug abuse science. Steve Goldberg's first several publications focused instead on stimulus-stimulus contingencies (respondent conditioning) in examining Abraham Wikler's two-factor hypothesis of relapse involving conditioned withdrawal and reinforcing effects of drugs. Goldberg provided a compelling demonstration that histories of contingencies among stimuli could produce lasting withdrawal reactions in primates formerly dependent on opioids. Other studies conducted by Goldberg extended the analysis of effects of stimulus-stimulus contingencies on behavior maintained by opioid reinforcing effects and showed that withdrawal-inducing antagonist administration can produce conditioned increases in self-administration. Subsequent studies of the effects of stimuli associated with cocaine injection under second-order schedules showed that the maintenance of behavior with drug injections was in most important aspects similar to the maintenance of behavior with more conventional reinforcers when the behavior-disrupting pharmacological effects of the drugs were minimized. Studies on second-order schedules demonstrated a wide array of conditions under which behavior could be maintained by drug injection and further influenced by stimulus-stimulus contingencies. These schedules present opportunities to produce in the laboratory complex situations involving response- and stimulus-stimulus contingencies, which go beyond simplistic pairings of stimuli and more closely approximate those found with human drug abusers. A focus on the response- and stimulus-stimulus contingencies, and resulting quantifiable changes in objective and quantifiable behavioral endpoints exemplified by the studies by Steve Goldberg, remains the most promising way forward for studying problems of drug dependence. PMID:26564234

  5. Stimulus equivalence: testing Sidman's (2000) theory.

    PubMed

    Minster, Sara Tepaeru; Jones, Max; Elliffe, Douglas; Muthukumaraswamy, Suresh D

    2006-05-01

    Sidman's (2000) theory regarding the origin of equivalence relations predicts that a reinforcing stimulus common to distinct equivalence classes must drop out of the equivalence relations. This prediction was tested in the present study by arranging class-specific reinforcers, R1 and R2, following correct responding on the prerequisite conditional discriminations (Ax-Bx, Cx-Bx) for two stimulus classes, A1B1C1 and A2B2C2. A class-common reinforcer, R3, was presented following correct responding on the prerequisite conditional discriminations for a further two stimulus classes, A3B3C3 and A4B4C4. Sidman's theory predicts reinforcer inclusion within Classes 1 and 2 only, given this training arrangement. Experiment 1 tested for the emergence of four equivalence classes and of stimulus-reinforcer and reinforcer-stimulus relations in each class. Four of the 6 subjects demonstrated the reinforcer-based relations in all four equivalence classes, rather than in only those classes with a class-specific reinforcer, as Sidman's theory predicts. One of the remaining 2 subjects showed the reinforcer-based relations in three of the four classes. Experiment 2 extended these findings to document the emergence of interclass matching relations based on the common reinforcer R3, in 5 of 6 subjects, such that a Class 3 sample occasioned the selection of a Class 4 sample when the Class 3 comparison was absent, and similarly, a Class 4 sample occasioned the selection of a Class 3 comparison when the Class 4 comparison was absent. These interclass relations emerged despite the simultaneous maintenance of Class 3 and 4 baseline conditional discriminations, so that the Class 3 and 4 stimuli and reinforcer simultaneously were, and were not, part of a single larger equivalence class. These data are irreconcilable with Sidman's theory, and question the utility of the application of the equivalence relation in describing derived stimulus relations.

  6. Temporal encoding of two-dimensional patterns by single units in primate primary visual cortex. I. Stimulus-response relations.

    PubMed

    Richmond, B J; Optican, L M; Spitzer, H

    1990-08-01

    criteria originally used by Hubel and Wiesel. The stimulus set elicited a wide variety of response strengths and patterns from each neuron. The responses from both the bars and the Walsh set could be used to differentiate and classify simple and complex cells. 4. The responses of both simple and complex cells showed striking stimulus-related strength and temporal modulation. For all of the complex cells there were instances where the responses to a stimulus and its contrast-reversed mate were substantially different in response strength or pattern, or both.(ABSTRACT TRUNCATED AT 400 WORDS)

  7. Carving executive control at its joints: Working memory capacity predicts stimulus-stimulus, but not stimulus-response, conflict.

    PubMed

    Meier, Matt E; Kane, Michael J

    2015-11-01

    Three experiments examined the relation between working memory capacity (WMC) and 2 different forms of cognitive conflict: stimulus-stimulus (S-S) and stimulus-response (S-R) interference. Our goal was to test whether WMC's relation to conflict-task performance is mediated by stimulus-identification processes (captured by S-S conflict), response-selection processes (captured by S-R conflict), or both. In Experiment 1, subjects completed a single task presenting both S-S and S-R conflict trials, plus trials that combined the 2 conflict types. We limited ostensible goal-maintenance contributions to performance by requiring the same goal for all trial types and by presenting frequent conflict trials that reinforced the goal. WMC predicted resolution of S-S conflict as expected: Higher WMC subjects showed reduced response time interference. Although WMC also predicted S-R interference, here, higher WMC subjects showed increased error interference. Experiment 2A replicated these results in a version of the conflict task without combined S-S/S-R trials. Experiment 2B increased the proportion of congruent (nonconflict) trials to promote reliance on goal-maintenance processes. Here, higher WMC subjects resolved both S-S and S-R conflict more successfully than did lower WMC subjects. The results were consistent with Kane and Engle's (2003) 2-factor theory of cognitive control, according to which WMC predicts executive-task performance through goal-maintenance and conflict-resolution processes. However, the present results add specificity to the account by suggesting that higher WMC subjects better resolve cognitive conflict because they more efficiently select relevant stimulus features against irrelevant, distracting ones.

  8. Stereoscopy Amplifies Emotions Elicited by Facial Expressions

    PubMed Central

    Kätsyri, Jari; Häkkinen, Jukka

    2015-01-01

    Mediated facial expressions do not elicit emotions as strongly as real-life facial expressions, possibly due to the low fidelity of pictorial presentations in typical mediation technologies. In the present study, we investigated the extent to which stereoscopy amplifies emotions elicited by images of neutral, angry, and happy facial expressions. The emotional self-reports of positive and negative valence (which were evaluated separately) and arousal of 40 participants were recorded. The magnitude of perceived depth in the stereoscopic images was manipulated by varying the camera base at 15, 40, 65, 90, and 115 mm. The analyses controlled for participants’ gender, gender match, emotional empathy, and trait alexithymia. The results indicated that stereoscopy significantly amplified the negative valence and arousal elicited by angry expressions at the most natural (65 mm) camera base, whereas stereoscopy amplified the positive valence elicited by happy expressions in both the narrowed and most natural (15–65 mm) base conditions. Overall, the results indicate that stereoscopy amplifies the emotions elicited by mediated emotional facial expressions when the depth geometry is close to natural. The findings highlight the sensitivity of the visual system to depth and its effect on emotions. PMID:27551358

  9. Stereoscopy Amplifies Emotions Elicited by Facial Expressions.

    PubMed

    Hakala, Jussi; Kätsyri, Jari; Häkkinen, Jukka

    2015-12-01

    Mediated facial expressions do not elicit emotions as strongly as real-life facial expressions, possibly due to the low fidelity of pictorial presentations in typical mediation technologies. In the present study, we investigated the extent to which stereoscopy amplifies emotions elicited by images of neutral, angry, and happy facial expressions. The emotional self-reports of positive and negative valence (which were evaluated separately) and arousal of 40 participants were recorded. The magnitude of perceived depth in the stereoscopic images was manipulated by varying the camera base at 15, 40, 65, 90, and 115 mm. The analyses controlled for participants' gender, gender match, emotional empathy, and trait alexithymia. The results indicated that stereoscopy significantly amplified the negative valence and arousal elicited by angry expressions at the most natural (65 mm) camera base, whereas stereoscopy amplified the positive valence elicited by happy expressions in both the narrowed and most natural (15-65 mm) base conditions. Overall, the results indicate that stereoscopy amplifies the emotions elicited by mediated emotional facial expressions when the depth geometry is close to natural. The findings highlight the sensitivity of the visual system to depth and its effect on emotions. PMID:27551358

  10. Stereoscopy Amplifies Emotions Elicited by Facial Expressions.

    PubMed

    Hakala, Jussi; Kätsyri, Jari; Häkkinen, Jukka

    2015-12-01

    Mediated facial expressions do not elicit emotions as strongly as real-life facial expressions, possibly due to the low fidelity of pictorial presentations in typical mediation technologies. In the present study, we investigated the extent to which stereoscopy amplifies emotions elicited by images of neutral, angry, and happy facial expressions. The emotional self-reports of positive and negative valence (which were evaluated separately) and arousal of 40 participants were recorded. The magnitude of perceived depth in the stereoscopic images was manipulated by varying the camera base at 15, 40, 65, 90, and 115 mm. The analyses controlled for participants' gender, gender match, emotional empathy, and trait alexithymia. The results indicated that stereoscopy significantly amplified the negative valence and arousal elicited by angry expressions at the most natural (65 mm) camera base, whereas stereoscopy amplified the positive valence elicited by happy expressions in both the narrowed and most natural (15-65 mm) base conditions. Overall, the results indicate that stereoscopy amplifies the emotions elicited by mediated emotional facial expressions when the depth geometry is close to natural. The findings highlight the sensitivity of the visual system to depth and its effect on emotions.

  11. Stimulus control of cocaine self-administration.

    PubMed

    Weiss, Stanley J; Kearns, David N; Cohn, Scott I; Schindler, Charles W; Panlilio, Leigh V

    2003-01-01

    Environmental stimuli that set the occasion wherein drugs are acquired can "trigger" drug-related behavior. Investigating the stimulus control of drug self-administration in laboratory animals should help us better understand this aspect of human drug abuse. Stimulus control of cocaine self-administration was generated here for the first time using multiple and chained schedules with short, frequently-alternating components--like those typically used to study food-maintained responding. The procedures and results are presented along with case histories to illustrate the strategies used to produce this stimulus control. All these multicomponent schedules contained variable-interval (VI) components as well as differential-reinforcement-of-other-behavior (DRO) or extinction components. Schedule parameters and unit dose were adjusted for each rat to produce stable, moderate rates in VI components, with minimal postreinforcement (infusion) pausing, and response cessation in extinction and DRO components. Whole-body drug levels on terminal baselines calculated retrospectively revealed that all rats maintained fairly stable drug levels (mean, 2.3 to 3.4 mg/kg) and molar rates of intake (approximately 6.0 mg/kg/hr). Within this range, no relation between local VI response rates and drug level was found. The stimulus control revealed in cumulative records was indistinguishable from that achieved with food under these schedules, suggesting that common mechanisms may underlie the control of cocaine- and food-maintained behavior.

  12. Stimulus Offers Funding Support for Ed. Facilities

    ERIC Educational Resources Information Center

    Ash, Katie

    2009-01-01

    Some two months after enactment of the federal economic-stimulus package, school facilities directors are still trying to piece together how much money will be available under the measure for school construction projects, what it can be used for, and when it can be accessed. Before President Barack Obama signed the $787 billion American Recovery…

  13. Disentangling the nature of the nicotine stimulus.

    PubMed

    Bevins, Rick A; Barrett, Scott T; Polewan, Robert J; Pittenger, Steven T; Swalve, Natashia; Charntikov, Sergios

    2012-05-01

    Learning involving interoceptive stimuli likely plays an important role in many diseases and psychopathologies. Within this area, there has been extensive research investigating the interoceptive stimulus effects of abused drugs. In this pursuit, behavioral pharmacologists have taken advantage of what is known about learning processes and adapted the techniques to investigate the behavioral and receptor mechanisms of drug stimuli. Of particular interest is the nicotine stimulus and the use of the two-lever operant drug discrimination task and the Pavlovian drug discriminated goal-tracking task. There is strong concordance between the two methods when using "standard" testing protocols that minimize learning on test days. For example, ABT-418, nornicotine, and varenicline all fully evoked nicotine-appropriate responding. Notably, research from our laboratory with the discriminated goal-tracking task has used an alternative testing protocol. This protocol assesses stimulus substitution based on how well extinction learning using a non-nicotine ligand transfers back to the nicotine stimulus. These findings challenge conclusions based on more "standard" testing procedures (e.g., ABT-418 is not nicotine-like). As a starting point, we propose Thurstone scaling as a quantitative method for more precisely comparing transfer of extinction across doses, experiments, and investigators. We close with a discussion of future research directions and potential implications of the research for understanding interoceptive stimuli.

  14. Electrophysiological Correlates of Stimulus Equivalence Processes

    ERIC Educational Resources Information Center

    Haimson, Barry; Wilkinson, Krista M.; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J.

    2009-01-01

    Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g.,…

  15. Facilities Bonds Prove Hot Item under Stimulus

    ERIC Educational Resources Information Center

    Klein, Alyson

    2009-01-01

    Construction bonding authority--a technical, and often obscure, source of capital funding for school districts--has emerged as a hot ticket for those looking to finance school facilities work under the federal government's economic-stimulus program. School districts left out of the loop for direct funding are lining up for some of at least $24…

  16. Stimulus Picture Identification in Articulation Testing

    ERIC Educational Resources Information Center

    Mullen, Patricia A.; Whitehead, Robert L.

    1977-01-01

    Compared with 20 normal speaking and 20 articulation defective Ss (7 and 8 years old) was the percent of correct initial identification of stimulus pictures on the Goldman-Fristoe Test of Articulation with the percent correct identification on the Arizona Articulation Proficiency Scale. (Author/IM)

  17. States Hurt as Stimulus Loses Steam

    ERIC Educational Resources Information Center

    Cavanagh, Sean; Hollingsworth, Heather

    2011-01-01

    States are finally arriving at the "funding cliff"--the point where about $100 billion in federal economic-stimulus aid for education runs out. The loss seems certain to compound severe budget woes and could mean thousands of school layoffs and the elimination of popular programs and services in districts across the country. The bulk of that…

  18. Infants' Bimodal Recognition of Human Stimulus Configurations.

    ERIC Educational Resources Information Center

    Francis, Patricia L.; McCroy, George

    The major purpose of this study was to examine bimodal coordination of featural stimuli in infancy. Specifically of interest was infant sensitivity to the auditory and visual combinations that characterize male and female stimulus configurations. A total of 27 male and 27 female subjects of 3, 6, and 9 months of age participated in the study.…

  19. Stimulus control of cocaine self-administration.

    PubMed Central

    Weiss, Stanley J; Kearns, David N; Cohn, Scott I; Schindler, Charles W; Panlilio, Leigh V

    2003-01-01

    Environmental stimuli that set the occasion wherein drugs are acquired can "trigger" drug-related behavior. Investigating the stimulus control of drug self-administration in laboratory animals should help us better understand this aspect of human drug abuse. Stimulus control of cocaine self-administration was generated here for the first time using multiple and chained schedules with short, frequently-alternating components--like those typically used to study food-maintained responding. The procedures and results are presented along with case histories to illustrate the strategies used to produce this stimulus control. All these multicomponent schedules contained variable-interval (VI) components as well as differential-reinforcement-of-other-behavior (DRO) or extinction components. Schedule parameters and unit dose were adjusted for each rat to produce stable, moderate rates in VI components, with minimal postreinforcement (infusion) pausing, and response cessation in extinction and DRO components. Whole-body drug levels on terminal baselines calculated retrospectively revealed that all rats maintained fairly stable drug levels (mean, 2.3 to 3.4 mg/kg) and molar rates of intake (approximately 6.0 mg/kg/hr). Within this range, no relation between local VI response rates and drug level was found. The stimulus control revealed in cumulative records was indistinguishable from that achieved with food under these schedules, suggesting that common mechanisms may underlie the control of cocaine- and food-maintained behavior. PMID:12696744

  20. Stimulus type and the list strength paradigm.

    PubMed

    Osth, Adam F; Dennis, Simon; Kinnell, Angela

    2014-01-01

    In recognition memory, increasing the strength of studied items does not reduce performance on other items, an effect dubbed the null list strength effect (LSE). While this finding has been replicated many times, it has rarely been tested using stimuli other than single words. Kinnell and Dennis ( 2012 ) recently tested for the presence of list length effects using non-word stimulus classes while controlling for the confounds that are present in list length designs. Small list length effects were found for fractal and face images. We adopted the same paradigm and stimuli used by Kinnell and Dennis to test whether these stimuli would be susceptible to list strength effects as well. We found significant LSEs for fractal images, but null LSEs for face images and natural scene photographs. Stimuli other than words do appear to be susceptible to list strength effects, but these effects are small and restricted to particular stimulus classes, as is the case in list length designs. Models of memory may be able to address differences between these stimulus classes by attributing differences in representational overlap between the stimulus classes.

  1. The Poverty of the Mayan Stimulus

    ERIC Educational Resources Information Center

    Pye, Clifton

    2012-01-01

    Poverty of the stimulus (POS) arguments have instigated considerable debate in the recent linguistics literature. This article uses the comparative method to challenge the logic of POS arguments. Rather than question the premises of POS arguments, the article demonstrates how POS arguments for individual languages lead to a "reductio ad absurdum"…

  2. Stimulus Equivalence: Testing Sidman's (2000) Theory

    ERIC Educational Resources Information Center

    Minster, Sara Tepaeru; Jones, Max; Elliffe, Douglas; Muthukumaraswamy, Suresh D.

    2006-01-01

    Sidman's (2000) theory regarding the origin of equivalence relations predicts that a reinforcing stimulus common to distinct equivalence classes must drop out of the equivalence relations. This prediction was tested in the present study by arranging class-specific reinforcers, R1 and R2, following correct responding on the prerequisite conditional…

  3. Stimulus Configuration, Classical Conditioning, and Hippocampal Function.

    ERIC Educational Resources Information Center

    Schmajuk, Nestor A.; DiCarlo, James J.

    1991-01-01

    The participation of the hippocampus in classical conditioning is described in terms of a multilayer network portraying stimulus configuration. A model of hippocampal function is presented, and computer simulations are used to study neural activity in the various brain areas mapped according to the model. (SLD)

  4. Stimulus Over-Selectivity in Rats

    ERIC Educational Resources Information Center

    Gibson, Evelyn; Reed, Phil

    2005-01-01

    The present study explored whether a similar phenomenon to stimulus over-selectivity occurred in rats, in the hope of establishing a non-human model for the autism. Rats were serially presented with two-15 seconds, two-element compound stimuli prior to the delivery of food, in an appetitive classical conditioning procedure. Each compound stimulus…

  5. Bigrams and the Richness of the Stimulus

    ERIC Educational Resources Information Center

    Kam, Xuan-Nga Cao; Stoyneshka, Iglika; Tornyova, Lidiya; Fodor, Janet D.; Sakas, William G.

    2008-01-01

    Recent challenges to Chomsky's "poverty of the stimulus" thesis for language acquisition suggest that children's primary data may carry "indirect evidence" about linguistic constructions despite containing no instances of them. Indirect evidence is claimed to suffice for grammar acquisition, without need for innate knowledge. This article reports…

  6. Evaluation of a Brief Stimulus Preference Assessment.

    ERIC Educational Resources Information Center

    Roane, Henry S.; Vollmer, Timothy R.; Ringdahl, Joel E.; Marcus, Bethany A.

    1998-01-01

    A study evaluated the utility of a five-minute stimulus preference assessment for 20 individuals with developmental disabilities. The brief assessment identified stimuli that functioned as reinforcers for a simple operant response and identified preferred stimuli that were differentially effective as reinforcers. This assessment was associated…

  7. Marginally subcritical dynamics explain enhanced stimulus discriminability under attention

    PubMed Central

    Tomen, Nergis; Rotermund, David; Ernst, Udo

    2014-01-01

    Recent experimental and theoretical work has established the hypothesis that cortical neurons operate close to a critical state which describes a phase transition from chaotic to ordered dynamics. Critical dynamics are suggested to optimize several aspects of neuronal information processing. However, although critical dynamics have been demonstrated in recordings of spontaneously active cortical neurons, little is known about how these dynamics are affected by task-dependent changes in neuronal activity when the cortex is engaged in stimulus processing. Here we explore this question in the context of cortical information processing modulated by selective visual attention. In particular, we focus on recent findings that local field potentials (LFPs) in macaque area V4 demonstrate an increase in γ-band synchrony and a simultaneous enhancement of object representation with attention. We reproduce these results using a model of integrate-and-fire neurons where attention increases synchrony by enhancing the efficacy of recurrent interactions. In the phase space spanned by excitatory and inhibitory coupling strengths, we identify critical points and regions of enhanced discriminability. Furthermore, we quantify encoding capacity using information entropy. We find a rapid enhancement of stimulus discriminability with the emergence of synchrony in the network. Strikingly, only a narrow region in the phase space, at the transition from subcritical to supercritical dynamics, supports the experimentally observed discriminability increase. At the supercritical border of this transition region, information entropy decreases drastically as synchrony sets in. At the subcritical border, entropy is maximized under the assumption of a coarse observation scale. Our results suggest that cortical networks operate at such near-critical states, allowing minimal attentional modulations of network excitability to substantially augment stimulus representation in the LFPs. PMID:25202240

  8. Marginally subcritical dynamics explain enhanced stimulus discriminability under attention.

    PubMed

    Tomen, Nergis; Rotermund, David; Ernst, Udo

    2014-01-01

    Recent experimental and theoretical work has established the hypothesis that cortical neurons operate close to a critical state which describes a phase transition from chaotic to ordered dynamics. Critical dynamics are suggested to optimize several aspects of neuronal information processing. However, although critical dynamics have been demonstrated in recordings of spontaneously active cortical neurons, little is known about how these dynamics are affected by task-dependent changes in neuronal activity when the cortex is engaged in stimulus processing. Here we explore this question in the context of cortical information processing modulated by selective visual attention. In particular, we focus on recent findings that local field potentials (LFPs) in macaque area V4 demonstrate an increase in γ-band synchrony and a simultaneous enhancement of object representation with attention. We reproduce these results using a model of integrate-and-fire neurons where attention increases synchrony by enhancing the efficacy of recurrent interactions. In the phase space spanned by excitatory and inhibitory coupling strengths, we identify critical points and regions of enhanced discriminability. Furthermore, we quantify encoding capacity using information entropy. We find a rapid enhancement of stimulus discriminability with the emergence of synchrony in the network. Strikingly, only a narrow region in the phase space, at the transition from subcritical to supercritical dynamics, supports the experimentally observed discriminability increase. At the supercritical border of this transition region, information entropy decreases drastically as synchrony sets in. At the subcritical border, entropy is maximized under the assumption of a coarse observation scale. Our results suggest that cortical networks operate at such near-critical states, allowing minimal attentional modulations of network excitability to substantially augment stimulus representation in the LFPs.

  9. Tracing the time course of emotion perception: the impact of stimulus physics and semantics on gesture processing.

    PubMed

    Flaisch, Tobias; Schupp, Harald T

    2013-10-01

    Numerous event-related brain potential (ERP) studies reveal the differential processing of emotional and neutral stimuli. Yet, it is an ongoing debate to what extent the ERP components found in previous research are sensitive to physical stimulus characteristics or emotional meaning. This study manipulated emotional meaning and stimulus orientation to disentangle the impact of stimulus physics and semantics on emotional stimulus processing. Negative communicative hand gestures of Insult were contrasted with neutral control gestures of Allusion to manipulate emotional meaning. An elementary physical manipulation of visual processing was implemented by presenting these stimuli vertically and horizontally. The results showed dissociable effects of stimulus meaning and orientation on the sequence of ERP components. Effects of orientation were pronounced in the P1 and N170 time frames and attenuated during later stages. Emotional meaning affected the P1, evincing a distinct topography to orientation effects. Although the N170 was not modulated by emotional meaning, the early posterior negativity and late positive potential components replicated previous findings with larger potentials elicited by the Insult gestures. These data suggest that the brain processes different attributes of an emotional picture in parallel and that a coarse semantic appreciation may already occur during relatively early stages of emotion perception.

  10. Event-related potentials elicited by social commerce and electronic-commerce reviews.

    PubMed

    Bai, Yan; Yao, Zhong; Cong, Fengyu; Zhang, Linlin

    2015-12-01

    There is an increasing interest regarding the use of electroencephalography (EEG) in social commerce and electronic commerce (e-commerce) research. There are several reviews in the field of social commerce or e-commerce; these have great potential value and mining them is fundamental and significant. To our knowledge, EEG is rarely applied to study these. In this study, we examined the neural correlates of social commerce reviews (SCRs) and e-commerce reviews (ECRs) by using them as stimuli to evoke event-related potentials. All SCRs were from friends through a social media platform, whereas ECRs were from strangers through an e-commerce platform. The experimental design was similar to that of a priming paradigm, and included 40 pairs of stimuli consisting of product information (prime stimulus) and reviews (target stimulus). The results showed that the P300 component was successfully evoked by SCR and ECR stimuli. Moreover, the P300 components elicited by SCRs had higher amplitudes than those elicited by ECRs. These findings indicate that participants paid more attention to SCRs than to ECRs. In addition, the associations between neural responses and reviews in social commerce have the potential to assist companies in studying consumer behaviors, thus permitting them to enhance their social commerce strategies.

  11. Event-related potentials elicited by social commerce and electronic-commerce reviews.

    PubMed

    Bai, Yan; Yao, Zhong; Cong, Fengyu; Zhang, Linlin

    2015-12-01

    There is an increasing interest regarding the use of electroencephalography (EEG) in social commerce and electronic commerce (e-commerce) research. There are several reviews in the field of social commerce or e-commerce; these have great potential value and mining them is fundamental and significant. To our knowledge, EEG is rarely applied to study these. In this study, we examined the neural correlates of social commerce reviews (SCRs) and e-commerce reviews (ECRs) by using them as stimuli to evoke event-related potentials. All SCRs were from friends through a social media platform, whereas ECRs were from strangers through an e-commerce platform. The experimental design was similar to that of a priming paradigm, and included 40 pairs of stimuli consisting of product information (prime stimulus) and reviews (target stimulus). The results showed that the P300 component was successfully evoked by SCR and ECR stimuli. Moreover, the P300 components elicited by SCRs had higher amplitudes than those elicited by ECRs. These findings indicate that participants paid more attention to SCRs than to ECRs. In addition, the associations between neural responses and reviews in social commerce have the potential to assist companies in studying consumer behaviors, thus permitting them to enhance their social commerce strategies. PMID:26557933

  12. Distinguishing Between Social Reinforcement and Social Elicitation.

    ERIC Educational Resources Information Center

    Bloom, Kathleen

    1984-01-01

    Discusses the distinction between species-typical (elicitation) and operant reinforcement interpretations of infant/adult social interaction; considers procedural and analytic components of Poulson's 1983 paper (v36 p471-89); and clarifies differences in Poulson's interpretation and the author's interpretation of the vocal conditioning studies of…

  13. Eliciting User Requirements Using Appreciative Inquiry

    ERIC Educational Resources Information Center

    Gonzales, Carol Kernitzki

    2010-01-01

    Many software development projects fail because they do not meet the needs of users, are over-budget, and abandoned. To address this problem, the user requirements elicitation process was modified based on principles of Appreciative Inquiry. Appreciative Inquiry, commonly used in organizational development, aims to build organizations, processes,…

  14. Beyond maximum speed—a novel two-stimulus paradigm for brain-computer interfaces based on event-related potentials (P300-BCI)

    NASA Astrophysics Data System (ADS)

    Kaufmann, Tobias; Kübler, Andrea

    2014-10-01

    Objective. The speed of brain-computer interfaces (BCI), based on event-related potentials (ERP), is inherently limited by the commonly used one-stimulus paradigm. In this paper, we introduce a novel paradigm that can increase the spelling speed by a factor of 2, thereby extending the one-stimulus paradigm to a two-stimulus paradigm. Two different stimuli (a face and a symbol) are presented at the same time, superimposed on different characters and ERPs are classified using a multi-class classifier. Here, we present the proof-of-principle that is achieved with healthy participants. Approach. Eight participants were confronted with the novel two-stimulus paradigm and, for comparison, with two one-stimulus paradigms that used either one of the stimuli. Classification accuracies (percentage of correctly predicted letters) and elicited ERPs from the three paradigms were compared in a comprehensive offline analysis. Main results. The accuracies slightly decreased with the novel system compared to the established one-stimulus face paradigm. However, the use of two stimuli allowed for spelling at twice the maximum speed of the one-stimulus paradigms, and participants still achieved an average accuracy of 81.25%. This study introduced an alternative way of increasing the spelling speed in ERP-BCIs and illustrated that ERP-BCIs may not yet have reached their speed limit. Future research is needed in order to improve the reliability of the novel approach, as some participants displayed reduced accuracies. Furthermore, a comparison to the most recent BCI systems with individually adjusted, rapid stimulus timing is needed to draw conclusions about the practical relevance of the proposed paradigm. Significance. We introduced a novel two-stimulus paradigm that might be of high value for users who have reached the speed limit with the current one-stimulus ERP-BCI systems.

  15. Some stimulus properties of inhalants: preliminary findings.

    PubMed

    Vila, J; Colotla, V A

    1981-01-01

    Water-deprived rats allowed access to 0.1% saccharin during 10 min followed by a 15-min (Exp. 1A) or a 30-min (Exp. 1B) exposure to lacquer thinner (6,360 ppm) failed to show a conditioned aversion to the saccharin solution. However, when the solvent odor was paired with water drinking followed by a 0.6 M LiCl injection (Exp. 2) the rats developed an aversion to water associated to lacquer thinner, drinking less than when water was presented alone. The findings suggest that whereas lacquer thinner does not appear to function as an unconditioned stimulus, it may acquire properties of conditioned stimulus in this paradigm of conditioned aversion. PMID:7335142

  16. Stimulus Contrast and Retinogeniculate Signal Processing.

    PubMed

    Rathbun, Daniel L; Alitto, Henry J; Warland, David K; Usrey, W Martin

    2016-01-01

    Neuronal signals conveying luminance contrast play a key role in nearly all aspects of perception, including depth perception, texture discrimination, and motion perception. Although much is known about the retinal mechanisms responsible for encoding contrast information, relatively little is known about the relationship between stimulus contrast and the processing of neuronal signals between visual structures. Here, we describe simultaneous recordings from monosynaptically connected retinal ganglion cells and lateral geniculate nucleus (LGN) neurons in the cat to determine how stimulus contrast affects the communication of visual signals between the two structures. Our results indicate that: (1) LGN neurons typically reach their half-maximal response at lower contrasts than their individual retinal inputs and (2) LGN neurons exhibit greater contrast-dependent phase advance (CDPA) than their retinal inputs. Further analyses suggests that increased sensitivity relies on spatial convergence of multiple retinal inputs, while increased CDPA is achieved, in part, on temporal summation of arriving signals. PMID:26924964

  17. Stimulus Contrast and Retinogeniculate Signal Processing

    PubMed Central

    Rathbun, Daniel L.; Alitto, Henry J.; Warland, David K.; Usrey, W. Martin

    2016-01-01

    Neuronal signals conveying luminance contrast play a key role in nearly all aspects of perception, including depth perception, texture discrimination, and motion perception. Although much is known about the retinal mechanisms responsible for encoding contrast information, relatively little is known about the relationship between stimulus contrast and the processing of neuronal signals between visual structures. Here, we describe simultaneous recordings from monosynaptically connected retinal ganglion cells and lateral geniculate nucleus (LGN) neurons in the cat to determine how stimulus contrast affects the communication of visual signals between the two structures. Our results indicate that: (1) LGN neurons typically reach their half-maximal response at lower contrasts than their individual retinal inputs and (2) LGN neurons exhibit greater contrast-dependent phase advance (CDPA) than their retinal inputs. Further analyses suggests that increased sensitivity relies on spatial convergence of multiple retinal inputs, while increased CDPA is achieved, in part, on temporal summation of arriving signals. PMID:26924964

  18. Stimulus Contrast and Retinogeniculate Signal Processing.

    PubMed

    Rathbun, Daniel L; Alitto, Henry J; Warland, David K; Usrey, W Martin

    2016-01-01

    Neuronal signals conveying luminance contrast play a key role in nearly all aspects of perception, including depth perception, texture discrimination, and motion perception. Although much is known about the retinal mechanisms responsible for encoding contrast information, relatively little is known about the relationship between stimulus contrast and the processing of neuronal signals between visual structures. Here, we describe simultaneous recordings from monosynaptically connected retinal ganglion cells and lateral geniculate nucleus (LGN) neurons in the cat to determine how stimulus contrast affects the communication of visual signals between the two structures. Our results indicate that: (1) LGN neurons typically reach their half-maximal response at lower contrasts than their individual retinal inputs and (2) LGN neurons exhibit greater contrast-dependent phase advance (CDPA) than their retinal inputs. Further analyses suggests that increased sensitivity relies on spatial convergence of multiple retinal inputs, while increased CDPA is achieved, in part, on temporal summation of arriving signals.

  19. Arrow-Elicited Cueing Effects at Short Intervals: Rapid Attentional Orienting or Cue-Target Stimulus Conflict?

    ERIC Educational Resources Information Center

    Green, Jessica J.; Woldorff, Marty G.

    2012-01-01

    The observation of cueing effects (faster responses for cued than uncued targets) rapidly following centrally-presented arrows has led to the suggestion that arrows trigger rapid automatic shifts of spatial attention. However, these effects have primarily been observed during easy target-detection tasks when both cue and target remain on the…

  20. Stimulus control in a two-choice discrimination procedure

    NASA Technical Reports Server (NTRS)

    Galloway, W. D.

    1973-01-01

    Experimental investigation upon pigeons of the relation between performance during discriminative training and subsequently obtained stimulus control test results. The results obtained support the proposition that bias generated by training dependencies is a major determiner of stimulus control.

  1. Ballistic exercise as a pre-activation stimulus: a review of the literature and practical applications.

    PubMed

    Maloney, Sean J; Turner, Anthony N; Fletcher, Iain M

    2014-10-01

    Post-activation potentiation (PAP) refers to the acute enhancement of muscular function as a direct result of its contractile history. Protocols designed to elicit PAP have commonly employed heavy resistance exercise (HRE) as the pre-activation stimulus; however, a growing body of research suggests that low-load ballistic exercises (BE) may also provide an effective stimulus. The ability to elicit PAP without the need for heavy equipment would make it easier to utilise prior to competition. It is hypothesised that BE can induce PAP given the high recruitment of type II muscle fibres associated with its performance. The literature has reported augmentations in power performance typically ranging from 2 to 5 %. The performance effects of BE are modulated by loading, recovery and physical characteristics. Jumps performed with an additional loading, such as depth jumps or weighted jumps, appear to be the most effective activities for inducing PAP. Whilst the impact of recovery duration on subsequent performance requires further research, durations of 1-6 min have been prescribed successfully in multiple instances. The effect of strength and sex on the PAP response to BE is not yet clear. Direct comparisons of BE and HRE, to date, suggest a tendency for HRE protocols to be more effective; future research should consider that these strategies must be optimised in different ways. The role of acute augmentations in lower limb stiffness is proposed as an additional mechanism that may further explain the PAP response following BE. In summary, BE demonstrates the potential to enhance performance in power tasks such as jumps and sprints. This review provides the reader with some practical recommendations for the application of BE as a pre-activation stimulus.

  2. Stimulus Requirements for Face Perception: An Analysis Based on “Totem Poles”

    PubMed Central

    Paras, Carrie L.; Webster, Michael A.

    2013-01-01

    The stimulus requirements for perceiving a face are not well defined but are presumably simple, for vivid faces can often by seen in random or natural images such as cloud or rock formations. To characterize these requirements, we measured where observers reported the impression of faces in images defined by symmetric 1/f noise. This allowed us to examine the prominence and properties of different features and their necessary configurations. In these stimuli many faces can be perceived along the vertical midline, and appear stacked at multiple scales, reminiscent of “totem poles.” In addition to symmetry, the faces in noise are invariably upright and thus reveal the inversion effects that are thought to be a defining property of configural face processing. To a large extent, seeing a face required seeing eyes, and these were largely restricted to dark regions in the images. Other features were more subordinate and showed relatively little bias in polarity. Moreover, the prominence of eyes depended primarily on their luminance contrast and showed little influence of chromatic contrast. Notably, most faces were rated as clearly defined with highly distinctive attributes, suggesting that once an image area is coded as a face it is perceptually completed consistent with this interpretation. This suggests that the requisite trigger features are sufficient to holistically “capture” the surrounding noise structure to form the facial representation. Yet despite these well articulated percepts, we show in further experiments that while a pair of dark spots added to noise images appears face-like, these impressions fail to elicit other signatures of face processing, and in particular, fail to elicit an N170 or fixation patterns typical for images of actual faces. These results suggest that very simple stimulus configurations are sufficient to invoke many aspects of holistic and configural face perception while nevertheless failing to fully engage the neural machinery

  3. Response entropy changes after noxius stimulus.

    PubMed

    Guerrero, Jose L; Matute, E; Alsina, E; Del Blanco, B; Gilsanz, F

    2012-06-01

    Small changes in the frequency of the electromyography could reflect an inadequate anesthetic or analgesic level, and it could be more specific than the hemodynamic monitors. The Datex-Ohmeda S/5 Entropy Module includes information about the electromyographic activity of the face muscles (response entropy--RE). The aim of our study is compare entropy and BIS ability to detect a nociceptive stimulus during a sevoflurane anesthesia. We designed an observational, prospective and descriptive study that included 20 patients. We performed sevoflurane anaesthesia induction, the end-tidal was kept at 3 and 4 %, during 15 min at each concentration, with no analgesic drug and no neuromuscular blocking agent, and we applied a nociceptive stimulus: tetanus 100 Hz, during 5 s. We set the standard monitorization, BIS, RE, and state entropy (SE) along the study. There was a significant difference between RE and SE post-noxious stimulus values at 3 and 4 % end-tidal sevoflurane (p < 0.05). Only RE changed significantly at the moment of the noxious stimulation at both sevoflurane concentrations studied (p < 0.05). In patients under general anesthesia only carried out with sevoflurane at concentrations that inhibit the movement to painful stimuli, the RE is a single parameter able to detect variations after the nociceptive stimulation.

  4. Stimulus generalization and operant context renewal.

    PubMed

    Podlesnik, Christopher A; Miranda-Dukoski, Ludmila

    2015-10-01

    Context renewal is the relapse of an extinguished response due to changing the stimulus context following extinction. Reinforcing operant responding in Context A and extinguishing in Context B results in relapse when either returning to Context A (ABA renewal) or introducing a novel Context C (ABC renewal). ABA renewal typically is greater than ABC renewal. The present study assessed whether renewal might be conceptualized through excitatory and inhibitory generalization gradients inferred from studies of stimulus generalization. We arranged one keylight-color alternation frequency for pigeons to signal reinforcement in Phase 1 and a different alternation frequency to signal extinction in Phase 2. During a subsequent test in extinction, we presented a range of keylight-alternation frequencies and found renewal to be a function of keylight-alternation frequency. Specifically, Phase-3 responding increased as keylight-alternation frequency differed from that arranged during extinction in Phase 2. Moreover, we observed a shift in the function beyond the originally reinforced keylight-alternation frequency arranged in training (i.e., peak shift). We discuss the relevance of these findings for conceptualizing stimulus-control processes governing generalization gradients for understanding the processes underlying context renewal. PMID:26241660

  5. Stimulus-responsive nanopreparations for tumor targeting.

    PubMed

    Zhu, Lin; Torchilin, Vladimir P

    2013-01-01

    Nanopreparations such as liposomes, micelles, polymeric and inorganic nanoparticles, and small molecule/nucleic acid/protein conjugates have demonstrated various advantages over "naked" therapeutic molecules. These nanopreparations can be further engineered with functional moieties to improve their performance in terms of circulation longevity, targetability, enhanced intracellular penetration, carrier-mediated enhanced visualization, and stimuli-sensitivity. The idea of application of a stimulus-sensitive drug or imaging agent delivery system for tumor targeting is based on the significant abnormalities in the tumor microenvironment and its cells, such as an acidic pH, altered redox potential, up-regulated proteins and hyperthermia. These internal conditions as well as external stimuli, such as magnetic field, ultrasound and light, can be used to modify the behavior of the nanopreparations that control drug release, improve drug internalization, control the intracellular drug fate and even allow for certain physical interactions, resulting in an enhanced tumor targeting and antitumor effect. This article provides a critical view of current stimulus-sensitive drug delivery strategies and possible future directions in tumor targeting with primary focus on the combined use of stimulus-sensitivity with other strategies in the same nanopreparation, including multifunctional nanopreparations and theranostics. PMID:22869005

  6. Stimulus-responsive nanopreparations for tumor targeting

    PubMed Central

    Zhu, Lin; Torchilin, Vladimir P.

    2012-01-01

    Nanopreparations such as liposomes, micelles, polymeric and inorganic nanoparticles, and small molecule/nucleic acid/protein conjugates have demonstrated various advantages versus “naked” therapeutic molecules. These nanopreparations can be further engineered with functional moieties to improve their performance in terms of circulation longevity, targetability, enhanced intracellular penetration; carrier-mediated enhanced visualization, and stimuli-sensitivity. The idea of application of a stimulus-sensitive drug or imaging agent delivery system for tumor targeting is based on the fact of the significant abnormalities in the tumor microenvironment and its cells, such as an acidic pH, altered redox potential, up-regulated proteins and hyperthermia. These internal conditions as well as external stimuli such as magnetic field, ultrasound and light, can be used to modify the behavior of the nanopreparations that control drug release, improve drug internalization, control the intracellular drug fate and even allow for certain physical interactions, resulting in an enhanced tumor targeting and antitumor effect. This article provides a critical view of current stimulus-sensitive drug delivery strategies and possible future directions in tumor targeting with primary focus on the combined use of stimulus-sensitivity with other strategies in the same nanopreparation, including multifunctional nanopreparations and theranostics. PMID:22869005

  7. Impact of stimulus uncanniness on speeded response

    PubMed Central

    Takahashi, Kohske; Fukuda, Haruaki; Samejima, Kazuyuki; Watanabe, Katsumi; Ueda, Kazuhiro

    2015-01-01

    In the uncanny valley phenomenon, the causes of the feeling of uncanniness as well as the impact of the uncanniness on behavioral performances still remain open. The present study investigated the behavioral effects of stimulus uncanniness, particularly with respect to speeded response. Pictures of fish were used as visual stimuli. Participants engaged in direction discrimination, spatial cueing, and dot-probe tasks. The results showed that pictures rated as strongly uncanny delayed speeded response in the discrimination of the direction of the fish. In the cueing experiment, where a fish served as a task-irrelevant and unpredictable cue for a peripheral target, we again observed that the detection of a target was slowed when the cue was an uncanny fish. Conversely, the dot-probe task suggested that uncanny fish, unlike threatening stimulus, did not capture visual spatial attention. These results suggested that stimulus uncanniness resulted in the delayed response, and importantly this modulation was not mediated by the feelings of threat. PMID:26052297

  8. Stimulus-responsive nanopreparations for tumor targeting.

    PubMed

    Zhu, Lin; Torchilin, Vladimir P

    2013-01-01

    Nanopreparations such as liposomes, micelles, polymeric and inorganic nanoparticles, and small molecule/nucleic acid/protein conjugates have demonstrated various advantages over "naked" therapeutic molecules. These nanopreparations can be further engineered with functional moieties to improve their performance in terms of circulation longevity, targetability, enhanced intracellular penetration, carrier-mediated enhanced visualization, and stimuli-sensitivity. The idea of application of a stimulus-sensitive drug or imaging agent delivery system for tumor targeting is based on the significant abnormalities in the tumor microenvironment and its cells, such as an acidic pH, altered redox potential, up-regulated proteins and hyperthermia. These internal conditions as well as external stimuli, such as magnetic field, ultrasound and light, can be used to modify the behavior of the nanopreparations that control drug release, improve drug internalization, control the intracellular drug fate and even allow for certain physical interactions, resulting in an enhanced tumor targeting and antitumor effect. This article provides a critical view of current stimulus-sensitive drug delivery strategies and possible future directions in tumor targeting with primary focus on the combined use of stimulus-sensitivity with other strategies in the same nanopreparation, including multifunctional nanopreparations and theranostics.

  9. Stimulus generalization and operant context renewal.

    PubMed

    Podlesnik, Christopher A; Miranda-Dukoski, Ludmila

    2015-10-01

    Context renewal is the relapse of an extinguished response due to changing the stimulus context following extinction. Reinforcing operant responding in Context A and extinguishing in Context B results in relapse when either returning to Context A (ABA renewal) or introducing a novel Context C (ABC renewal). ABA renewal typically is greater than ABC renewal. The present study assessed whether renewal might be conceptualized through excitatory and inhibitory generalization gradients inferred from studies of stimulus generalization. We arranged one keylight-color alternation frequency for pigeons to signal reinforcement in Phase 1 and a different alternation frequency to signal extinction in Phase 2. During a subsequent test in extinction, we presented a range of keylight-alternation frequencies and found renewal to be a function of keylight-alternation frequency. Specifically, Phase-3 responding increased as keylight-alternation frequency differed from that arranged during extinction in Phase 2. Moreover, we observed a shift in the function beyond the originally reinforced keylight-alternation frequency arranged in training (i.e., peak shift). We discuss the relevance of these findings for conceptualizing stimulus-control processes governing generalization gradients for understanding the processes underlying context renewal.

  10. Finding the missing stimulus mismatch negativity (MMN): emitted MMN to violations of an auditory gestalt.

    PubMed

    Salisbury, Dean F

    2012-04-01

    Deviations from repetitive auditory stimuli evoke a mismatch negativity (MMN). Counterintuitively, omissions of repetitive stimuli do not. Violations of patterns reflecting complex rules also evoke MMN. To detect a MMN to missing stimuli, we developed an auditory gestalt task using one stimulus. Groups of six pips (50 ms duration, 330 ms stimulus onset asynchrony [SOA], 400 trials), were presented with an intertrial interval (ITI) of 750 ms while subjects (n=16) watched a silent video. Occasional deviant groups had missing 4th or 6th tones (50 trials each). Missing stimuli evoked a MMN (p<.05). The missing 4th (-0.8 µV, p<.01) and the missing 6th stimuli (-1.1 µV, p<.05) were more negative than standard 6th stimuli (0.3 µV). MMN can be elicited by a missing stimulus at long SOAs by violation of a gestalt grouping rule. Patterned stimuli appear more sensitive to omissions and ITI than homogenous streams. PMID:22221004

  11. Changes in Compensatory Eye Movements Associated with Simulated Stimulus Conditions of Spaceflight

    NASA Technical Reports Server (NTRS)

    Harm, Deborah L.; Zografos, Linda M.; Skinner, Noel C.; Parker, Donald E.

    1993-01-01

    Compensatory vertical eye movement gain (CVEMG) was recorded during pitch oscillation in darkness before, during and immediately after exposures to the stimulus rearrangement produced by the Preflight Adaptation Trainer (PAT) Tilt-Translation Device (TTD). The TTD is designed to elicit adaptive responses that are similar to those observed in microgravity-adapted astronauts. The data from Experiment 1 yielded a statistically significant CVEMG decrease following 15 minutes of exposure to a stimulus rearrangement condition where the phase angle between subject pitch tilt and visual scene translation was 270 degrees; statistically significant gain decreases were not observed following exposures either to a condition where the phase angle between subject pitch and scene translation was 90 degrees or to a no-stimulus-rearrangement condition. Experiment 2 replicated the 270 degree phase condition from Experiment 1 and extended the exposure duration from 30 to 45 minutes. Statistically significant additional changes in CVEMG associated with the increased exposure duration were not observed. The adaptation time constant estimated from the combined data from Experiments 1 and 2 was 29 minutes.

  12. Changes in compensatory eye movements associated with simulated stimulus conditions of spaceflight

    NASA Technical Reports Server (NTRS)

    Harm, Deborah L.; Zografos, Linda M.; Skinner, Noel C.; Parker, Donald E.

    1993-01-01

    Compensatory vertical eye movement gain (CVEMG) was recorded during pitch oscillation in darkness before, during, and immediately after exposures to the stimulus rearrangement produced by the Preflight Adaptation Trainer (PAT) Tilt-Translation Device (TTD). The TTD is designed to elicit adaptive responses that are similar to those observed in microgravity-adapted astronauts. The data from Experiment 1 yielded a statistically significant CVEMG decrease following 15 min of exposure to a stimulus rearrangement condition where the phase angle between subject pitch tilt and visual scene translation was 270 deg; statistically significant gain decreases were not observed following exposures either to a condition where the phase angle between subject pitch and scene translation was 90 deg or to a no-stimulus-rearrangement condition. Experiment 2 replicated the 270-deg-phase condition from Experiment 1 and extended the exposure duration from 30 to 45 min. Statistically significant additional changes in CVEMG associated with the increased exposure duration were not observed. The adaptation time constant estimated fram the combined data from Experiments 1 and 2 was 29 min.

  13. Finding the missing stimulus mismatch negativity (MMN): emitted MMN to violations of an auditory gestalt.

    PubMed

    Salisbury, Dean F

    2012-04-01

    Deviations from repetitive auditory stimuli evoke a mismatch negativity (MMN). Counterintuitively, omissions of repetitive stimuli do not. Violations of patterns reflecting complex rules also evoke MMN. To detect a MMN to missing stimuli, we developed an auditory gestalt task using one stimulus. Groups of six pips (50 ms duration, 330 ms stimulus onset asynchrony [SOA], 400 trials), were presented with an intertrial interval (ITI) of 750 ms while subjects (n=16) watched a silent video. Occasional deviant groups had missing 4th or 6th tones (50 trials each). Missing stimuli evoked a MMN (p<.05). The missing 4th (-0.8 µV, p<.01) and the missing 6th stimuli (-1.1 µV, p<.05) were more negative than standard 6th stimuli (0.3 µV). MMN can be elicited by a missing stimulus at long SOAs by violation of a gestalt grouping rule. Patterned stimuli appear more sensitive to omissions and ITI than homogenous streams.

  14. Dynamic dendritic compartmentalization underlies stimulus-specific adaptation in an insect neuron.

    PubMed

    Prešern, Janez; Triblehorn, Jeffrey D; Schul, Johannes

    2015-06-01

    In many neural systems, repeated stimulation leads to stimulus-specific adaptation (SSA), with responses to repeated signals being reduced while responses to novel stimuli remain unaffected. The underlying mechanisms of SSA remain mostly hypothetical. One hypothesis is that dendritic processes generate SSA. Evidence for such a mechanism was recently described in an insect auditory interneuron (TN-1 in Neoconocephalus triops). Afferents, tuned to different frequencies, connect with different parts of the TN-1 dendrite. The specific adaptation of these inputs relies on calcium and sodium accumulation within the dendrite, with calcium having a transient and sodium a tonic effect. Using imaging techniques, we tested here whether the accumulation of these ions remained limited to the stimulated parts of the dendrite. Stimulation with a fast pulse rate, which results in strong adaptation, elicited a transient dendritic calcium signal. In contrast, the sodium signal was tonic, remaining high during the fast pulse rate stimulus. These time courses followed the predictions from the previous pharmacological experiments. The peak positions of the calcium and sodium signals differed with the carrier frequency of the stimulus; at 15 kHz, peak locations were significantly more rostral than at 40 kHz. This matched the predictions made from neuroanatomical data. Our findings confirm that excitatory postsynaptic potentials rather than spiking cause the increase of dendritic calcium and sodium concentrations and that these increases remain limited to the stimulated parts of the dendrite. This supports the hypothesis of "dynamic dendritic compartmentalization" underlying SSA in this auditory interneuron. PMID:25878158

  15. Comparison of aortic and carotid baroreflex stimulus-response characteristics in humans

    NASA Technical Reports Server (NTRS)

    Smith, S. A.; Querry, R. G.; Fadel, P. J.; Weiss, M. W.; Olivencia-Yurvati, A.; Shi, X.; Raven, P. B.

    2001-01-01

    In order to characterize the stimulus-response relationships of the arterial, aortic, and carotid baroreflexes in mediating cardiac chronotropic function, we measured heart rate (HR) responses elicited by acute changes in mean arterial pressure (MAP) and carotid sinus pressure (CSP) in 11 healthy individuals. Arterial (aortic + carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of phenylephrine (PE) and sodium nitroprusside (SN). To assess aortic-cardiac responses, neck pressure (NP) and suction (NS) were applied during PE and SN administration, respectively, to counter alterations in CSP thereby isolating the aortic baroreflex. Graded levels of NP and NS were delivered to the carotid sinus using a customized neck collar device to assess the carotid-cardiac baroreflex, independent of drug infusion. The operating characteristics of each reflex were determined from the logistic function of the elicited HR response to the induced change in MAP. The arterial pressures at which the threshold was located on the stimulus-response curves determined for the arterial, aortic and carotid baroreflexes were not significantly different (72+/-4, 67+/-3, and 72+/-4 mm Hg, respectively, P > 0.05). Similarly, the MAP at which the saturation of the reflex responses were elicited did not differ among the baroreflex arcs examined (98+/-3, 99+/-2, and 102+/-3 mm Hg, respectively). These data suggest that the baroreceptor populations studied operate over the same range of arterial pressures. This finding indicates each baroreflex functions as both an important anti-hypotensive and anti-hypertensive mechanism. In addition, this investigation describes a model of aortic baroreflex function in normal healthy humans, which may prove useful in identifying the origin of baroreflex dysfunction in disease- and training-induced conditions.

  16. Measuring Joint Stimulus Control by Complex Graph/Description Correspondences

    ERIC Educational Resources Information Center

    Fields, Lanny; Spear, Jack

    2012-01-01

    Joint stimulus control occurs when responding is determined by the correspondence of elements of a complex sample and a complex comparison stimulus. In academic settings, joint stimulus control of behavior would be evidenced by the selection of an accurate description of a complex graph in which each element of a graph corresponded to particular…

  17. Evaluation of Antioxidant and Antibacterial Potentials of Nigella sativa L. Suspension Cultures under Elicitation.

    PubMed

    Chaudhry, Hera; Fatima, Nida; Ahmad, Iffat Zareen

    2015-01-01

    Nigella sativa L. (family Ranunculaceae) is an annual herb of immense medicinal properties because of its major active components (i.e., thymoquinone (TQ), thymohydroquinone (THQ), and thymol (THY)). Plant tissue culture techniques like elicitation, Agrobacterium mediated transformation, hairy root culture, and so on, are applied for substantial metabolite production. This study enumerates the antibacterial and antioxidant potentials of N. sativa epicotyl suspension cultures under biotic and abiotic elicitation along with concentration optimization of the elicitors for enhanced TQ and THY production. Cultures under different concentrations of pectin and manganese chloride (MnCl2) elicitation (i.e., 5 mg/L, 10 mg/L, and 15 mg/L) showed that the control, MnCl2 10 mg/L, and pectin 15 mg/L suspension extracts greatly inhibited the growth of E. coli, S. typhimurium, and S. aureus (MIC against E. coli, i.e., 2.35 ± 0.8, 2.4 ± 0.2, and 2.46 ± 0.5, resp.). Elicitation decreased SOD enzyme activity whereas CAT enzyme activity increased remarkably under MnCl2 elicitation. MnCl2 10 mg/L and pectin 15 mg/L elicitation enhanced the DPPH radical inhibition ability, but ferric scavenging activity was comparable to the control. TQ and THY were quantified by LC-MS/MS in the cultures with high bioactive properties revealing maximum content under MnCl2 10 mg/L elicitation. Therefore, MnCl2 elicitation can be undertaken on large scale for sustainable metabolite production.

  18. Evaluation of Antioxidant and Antibacterial Potentials of Nigella sativa L. Suspension Cultures under Elicitation

    PubMed Central

    Chaudhry, Hera; Fatima, Nida; Ahmad, Iffat Zareen

    2015-01-01

    Nigella sativa L. (family Ranunculaceae) is an annual herb of immense medicinal properties because of its major active components (i.e., thymoquinone (TQ), thymohydroquinone (THQ), and thymol (THY)). Plant tissue culture techniques like elicitation, Agrobacterium mediated transformation, hairy root culture, and so on, are applied for substantial metabolite production. This study enumerates the antibacterial and antioxidant potentials of N. sativa epicotyl suspension cultures under biotic and abiotic elicitation along with concentration optimization of the elicitors for enhanced TQ and THY production. Cultures under different concentrations of pectin and manganese chloride (MnCl2) elicitation (i.e., 5 mg/L, 10 mg/L, and 15 mg/L) showed that the control, MnCl2 10 mg/L, and pectin 15 mg/L suspension extracts greatly inhibited the growth of E. coli, S. typhimurium, and S. aureus (MIC against E. coli, i.e., 2.35 ± 0.8, 2.4 ± 0.2, and 2.46 ± 0.5, resp.). Elicitation decreased SOD enzyme activity whereas CAT enzyme activity increased remarkably under MnCl2 elicitation. MnCl2 10 mg/L and pectin 15 mg/L elicitation enhanced the DPPH radical inhibition ability, but ferric scavenging activity was comparable to the control. TQ and THY were quantified by LC-MS/MS in the cultures with high bioactive properties revealing maximum content under MnCl2 10 mg/L elicitation. Therefore, MnCl2 elicitation can be undertaken on large scale for sustainable metabolite production. PMID:26347883

  19. Failure to observe untested derived stimulus relations in extinction: implications for understanding stimulus-equivalence formation.

    PubMed

    Doughty, Adam H; Leake, Lesley W; Stoudemire, M Lee

    2014-11-01

    Wilson and Hayes (1996) and Doughty, Kastner, and Bismark (2011) observed resurgence of past equivalence relations when newer equivalence relations were punished or extinguished, respectively. Their findings support the notion that deriving stimulus relations is a form of operant behavior. Although there is consensus regarding the operant nature of deriving untrained stimulus relations, the necessary and sufficient conditions that establish these relations remain unclear. For example, in the aforementioned work, the resurgent equivalence relations were tested earlier in each study. The present research investigated whether this resurgence of equivalence relations requires their initial testing. In Experiment 1, college students received arbitrary matching-to-sample training in Phase 1. After these baseline discriminations were established, equivalence testing was omitted. In Phase 2, four 4-member equivalence classes were established that were inconsistent with the Phase-1 training. These Phase-2 relations then were extinguished to test whether the equivalence relations consistent with Phase-1 training would occur. Unlike in earlier research, these untested relations did not occur reliably. This finding was replicated in Experiment 2, and additional tests of stimulus relatedness did not reveal any evidence of derived stimulus relations consistent with the Phase-1 training. The present research extends other findings suggesting that the equivalence-testing context helps establish these stimulus classes.

  20. Failure to observe untested derived stimulus relations in extinction: implications for understanding stimulus-equivalence formation.

    PubMed

    Doughty, Adam H; Leake, Lesley W; Stoudemire, M Lee

    2014-11-01

    Wilson and Hayes (1996) and Doughty, Kastner, and Bismark (2011) observed resurgence of past equivalence relations when newer equivalence relations were punished or extinguished, respectively. Their findings support the notion that deriving stimulus relations is a form of operant behavior. Although there is consensus regarding the operant nature of deriving untrained stimulus relations, the necessary and sufficient conditions that establish these relations remain unclear. For example, in the aforementioned work, the resurgent equivalence relations were tested earlier in each study. The present research investigated whether this resurgence of equivalence relations requires their initial testing. In Experiment 1, college students received arbitrary matching-to-sample training in Phase 1. After these baseline discriminations were established, equivalence testing was omitted. In Phase 2, four 4-member equivalence classes were established that were inconsistent with the Phase-1 training. These Phase-2 relations then were extinguished to test whether the equivalence relations consistent with Phase-1 training would occur. Unlike in earlier research, these untested relations did not occur reliably. This finding was replicated in Experiment 2, and additional tests of stimulus relatedness did not reveal any evidence of derived stimulus relations consistent with the Phase-1 training. The present research extends other findings suggesting that the equivalence-testing context helps establish these stimulus classes. PMID:25306940

  1. Decoding Subjective Intensity of Nociceptive Pain from Pre-stimulus and Post-stimulus Brain Activities.

    PubMed

    Tu, Yiheng; Tan, Ao; Bai, Yanru; Hung, Yeung Sam; Zhang, Zhiguo

    2016-01-01

    Pain is a highly subjective experience. Self-report is the gold standard for pain assessment in clinical practice, but it may not be available or reliable in some populations. Neuroimaging data, such as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), have the potential to be used to provide physiology-based and quantitative nociceptive pain assessment tools that complements self-report. However, existing neuroimaging-based nociceptive pain assessments only rely on the information in pain-evoked brain activities, but neglect the fact that the perceived intensity of pain is also encoded by ongoing brain activities prior to painful stimulation. Here, we proposed to use machine learning algorithms to decode pain intensity from both pre-stimulus ongoing and post-stimulus evoked brain activities. Neural features that were correlated with intensity of laser-evoked nociceptive pain were extracted from high-dimensional pre- and post-stimulus EEG and fMRI activities using partial least-squares regression (PLSR). Further, we used support vector machine (SVM) to predict the intensity of pain from pain-related time-frequency EEG patterns and BOLD-fMRI patterns. Results showed that combining predictive information in pre- and post-stimulus brain activities can achieve significantly better performance in classifying high-pain and low-pain and in predicting the rating of perceived pain than only using post-stimulus brain activities. Therefore, the proposed pain prediction method holds great potential in basic research and clinical applications.

  2. Stimulus specificity of a steady-state visual-evoked potential-based brain-computer interface

    NASA Astrophysics Data System (ADS)

    Ng, Kian B.; Bradley, Andrew P.; Cunnington, Ross

    2012-06-01

    The mechanisms of neural excitation and inhibition when given a visual stimulus are well studied. It has been established that changing stimulus specificity such as luminance contrast or spatial frequency can alter the neuronal activity and thus modulate the visual-evoked response. In this paper, we study the effect that stimulus specificity has on the classification performance of a steady-state visual-evoked potential-based brain-computer interface (SSVEP-BCI). For example, we investigate how closely two visual stimuli can be placed before they compete for neural representation in the cortex and thus influence BCI classification accuracy. We characterize stimulus specificity using the four stimulus parameters commonly encountered in SSVEP-BCI design: temporal frequency, spatial size, number of simultaneously displayed stimuli and their spatial proximity. By varying these quantities and measuring the SSVEP-BCI classification accuracy, we are able to determine the parameters that provide optimal performance. Our results show that superior SSVEP-BCI accuracy is attained when stimuli are placed spatially more than 5° apart, with size that subtends at least 2° of visual angle, when using a tagging frequency of between high alpha and beta band. These findings may assist in deciding the stimulus parameters for optimal SSVEP-BCI design.

  3. Stimulus Specificity of Brain-Computer Interfaces Based on Code Modulation Visual Evoked Potentials

    PubMed Central

    Wei, Qingguo; Feng, Siwei; Lu, Zongwu

    2016-01-01

    A brain-computer interface (BCI) based on code modulated visual evoked potentials (c-VEP) is among the fastest BCIs that have ever been reported, but it has not yet been given a thorough study. In this study, a pseudorandom binary M sequence and its time lag sequences are utilized for modulation of different stimuli and template matching is adopted as the method for target recognition. Five experiments were devised to investigate the effect of stimulus specificity on target recognition and we made an effort to find the optimal stimulus parameters for size, color and proximity of the stimuli, length of modulation sequence and its lag between two adjacent stimuli. By changing the values of these parameters and measuring classification accuracy of the c-VEP BCI, an optimal value of each parameter can be attained. Experimental results of ten subjects showed that stimulus size of visual angle 3.8°, white, spatial proximity of visual angle 4.8° center to center apart, modulation sequence of length 63 bits and the lag of 4 bits between adjacent stimuli yield individually superior performance. These findings provide a basis for determining stimulus presentation of a high-performance c-VEP based BCI system. PMID:27243454

  4. Stimulus Specificity of Brain-Computer Interfaces Based on Code Modulation Visual Evoked Potentials.

    PubMed

    Wei, Qingguo; Feng, Siwei; Lu, Zongwu

    2016-01-01

    A brain-computer interface (BCI) based on code modulated visual evoked potentials (c-VEP) is among the fastest BCIs that have ever been reported, but it has not yet been given a thorough study. In this study, a pseudorandom binary M sequence and its time lag sequences are utilized for modulation of different stimuli and template matching is adopted as the method for target recognition. Five experiments were devised to investigate the effect of stimulus specificity on target recognition and we made an effort to find the optimal stimulus parameters for size, color and proximity of the stimuli, length of modulation sequence and its lag between two adjacent stimuli. By changing the values of these parameters and measuring classification accuracy of the c-VEP BCI, an optimal value of each parameter can be attained. Experimental results of ten subjects showed that stimulus size of visual angle 3.8°, white, spatial proximity of visual angle 4.8° center to center apart, modulation sequence of length 63 bits and the lag of 4 bits between adjacent stimuli yield individually superior performance. These findings provide a basis for determining stimulus presentation of a high-performance c-VEP based BCI system.

  5. Olfactory hallucinations elicited by electrical stimulation via subdural electrodes: effects of direct stimulation of olfactory bulb and tract.

    PubMed

    Kumar, Gogi; Juhász, Csaba; Sood, Sandeep; Asano, Eishi

    2012-06-01

    In 1954, Penfield and Jasper briefly described that percepts of unpleasant odor were elicited by intraoperative electrical stimulation of the olfactory bulb in patients with epilepsy. Since then, few peer-reviewed studies have reported such phenomena elicited by stimulation mapping via subdural electrodes implanted on the ventral surface of the frontal lobe. Here, we determined what types of olfactory hallucinations could be reproduced by such stimulation in children with focal epilepsy. This study included 16 children (age range: 5 to 17 years) who underwent implantation of subdural electrodes to localize the presumed epileptogenic zone and eloquent areas. Pairs of electrodes were electrically stimulated, and clinical responses were observed. In case a patient reported a perception, she/he was asked to describe its nature. We also described the stimulus parameters to elicit a given symptom. Eleven patients reported a perception of smell in response to electrical stimulation while the remaining five did not. Nine patients perceived an unpleasant smell (like bitterness, smoke, or garbage) while two perceived a pleasant smell (like strawberry or good food). Such olfactory hallucinations were induced by stimulation proximal to the olfactory bulb or tract on either hemisphere but not by that of orbitofrontal gyri lateral to the medial orbital sulci. The range of stimulus parameters employed to elicit olfactory hallucinations was comparable to those for other sensorimotor symptoms. Our systematic study of children with epilepsy replicated stimulation-induced olfactory hallucinations. We failed to provide evidence that a positive olfactory perception could be elicited by conventional stimulation of secondary olfactory cortex alone.

  6. The relationship between stimulus equivalence and verbal behavior

    PubMed Central

    Hall, Genae A.; Chase, Philip N.

    1991-01-01

    Despite the apparent similarity between stimulus equivalence and verbal behavior, these phenomena have been described in different terms. With different terminologies for each phenomenon, the precise nature of their relationship is difficult to determine. To explore this relationship, this paper first defines stimulus equivalence using a synthesis of the mathematical definition of the equivalence relation and Sidman and Tailby's (1982) definition. Selected examples of stimulus equivalence are then described as verbal behavior using Skinner's (1957) terminology. The paper then cites instances of verbal behavior that cannot be described as stimulus equivalence and considers whether there are instances of stimulus equivalence that cannot be described as verbal behavior. PMID:22477634

  7. Essays on probability elicitation scoring rules

    NASA Astrophysics Data System (ADS)

    Firmino, Paulo Renato A.; dos Santos Neto, Ademir B.

    2012-10-01

    In probability elicitation exercises it has been usual to considerer scoring rules (SRs) to measure the performance of experts when inferring about a given unknown, Θ, for which the true value, θ*, is (or will shortly be) known to the experimenter. Mathematically, SRs quantify the discrepancy between f(θ) (the distribution reflecting the expert's uncertainty about Θ) and d(θ), a zero-one indicator function of the observation θ*. Thus, a remarkable characteristic of SRs is to contrast expert's beliefs with the observation θ*. The present work aims at extending SRs concepts and formulas for the cases where Θ is aleatory, highlighting advantages of goodness-of-fit and entropy-like measures. Conceptually, it is argued that besides of evaluating the personal performance of the expert, SRs may also play a role when comparing the elicitation processes adopted to obtain f(θ). Mathematically, it is proposed to replace d(θ) by g(θ), the distribution that model the randomness of Θ, and do also considerer goodness-of-fit and entropylike metrics, leading to SRs that measure the adherence of f(θ) to g(θ). The implications of this alternative perspective are discussed and illustrated by means of case studies based on the simulation of controlled experiments. The usefulness of the proposed approach for evaluating the performance of experts and elicitation processes is investigated.

  8. Contrast and stimulus duration dependence of perceptual surround suppression in older adults.

    PubMed

    Karas, Renee; McKendrick, Allison M

    2015-05-01

    Most natural visual tasks involve the extraction of visual features from suprathreshold contrast backgrounds, hence an understanding of how ageing impacts on contrast mechanisms is essential to understand elderly visual function. Previous studies have revealed increased perceptual surround suppression of contrast in older adults. We aimed to determine whether such age-related effects depend on the centre or surround stimulus contrast as the neurophysiological mechanisms underpinning contrast-contrast suppression depend on such contrast relationships. We also measured surround suppression of contrast for longer duration and shorter duration stimuli to explore for effects of surround adaptation Fifteen younger and 15 older adults performed a centre-surround contrast discrimination task for a variety of centre-surround contrast combinations (20%, 40% and 80% contrast). Stimulus duration was 500ms. The 40% centre, 80% surround condition was also presented for 100ms duration. Relative to younger adults, perceptual surround suppression was increased for the older group for low, but clearly suprathreshold, central contrasts (20% contrast), whilst both groups performed similarly for stimuli with high centre contrasts. Data was best fit by a model with both increased inhibitory and excitatory weightings in the older group. Reduced stimulus duration increased perceptual surround suppression for both groups consistent with reduced adaptation to the surround, and did not explain the difference in suppression magnitude between groups. Understanding the stimulus parameters that elicit increased surround suppression in older adults is key to directing future work exploring underlying neural substrates, in addition to potentially being useful for predicting performance on more complicated natural visual tasks such as object and scene perception.

  9. The effect on human salivary flow rate of the temperature of a gustatory stimulus.

    PubMed

    Dawes, C; O'Connor, A M; Aspen, J M

    2000-11-01

    In the first study, whole saliva was collected from ten adults during stimulation with sour, carbonated, sweet and water stimuli in the form of 5-ml of ice at about -10 degrees C or of liquids at 0, 8, 20 or 37 degrees C. Parotid saliva was also collected in response to ice or infusion into the mouth of the liquids at different temperatures. Another group of ten adults also collected whole saliva in response to water at 20 degrees C, with or without the presence in the mouth of an acrylic cube of dimensions similar to those of the ice. In a second study, 20 adults collected whole saliva in response to stimulation with 5 ml of water and of an astringent stimulus at 0, 8, 37 and 70 degrees C. In the first study, flow rates fell in the order sour, carbonated, sweet and water and flow rates in response to stimuli in the form of ice were very significantly higher than in response to the corresponding liquids at the four different temperatures. With the sour stimulus, liquids at 0 and 8 degrees C elicited higher flow rates than liquids at 20 or 37 degrees C. Although the presence in the mouth of the acrylic block increased the flow rate of whole saliva, the increase was only about 30% of that achieved with ice. In the second study, the astringent stimulus was a more effective salivary stimulus than water; flow rates were significantly higher in response to liquids at 0 and 8 degrees C than at the higher temperatures and flow rates in response to liquids at 37 degrees C were significantly lower than with the other temperatures. In summary, stimuli in the form of ice were the most effective and liquids at 37 degrees C were least effective in stimulating salivary flow. PMID:11000382

  10. Stimulus control topography coherence theory: foundations and extensions.

    PubMed

    McIlvane, William J; Dube, William V

    2003-01-01

    Stimulus control topography refers to qualitative differences among members of a functional stimulus class. Stimulus control topography coherence refers to the degree of concordance between the stimulus properties specified as relevant by the individual arranging a reinforcement contingency (behavior analyst, experimenter, teacher, etc.) and the stimulus properties that come to control the behavior of the organism (experimental subject, student, etc.) that experiences those contingencies. This paper summarizes the rationale for analyses of discrimination learning outcomes in terms of stimulus control topography coherence and briefly reviews some of the foundational studies that led to this perspective. We also suggest directions for future research, including pursuit of conceptual and methodological challenges to a complete stimulus control topography coherence analysis of processes involved in discriminated and generalized operants.

  11. Rate dependency of vibrotactile stimulus modulation.

    PubMed

    Francisco, E; Holden, J; Zhang, Z; Favorov, O; Tommerdahl, M

    2011-09-30

    Adaptation has a pronounced impact on the perception of vibrotactile stimuli. Previously, we demonstrated that the duration of vibrotactile conditioning was directly proportional to the impact that adaptation has on sensory perception (Tannan et al., 2007b). Prior reports had proposed that the impact of adaptation on the perceived magnitude of vibrotactile stimuli was specific to the conditioning amplitude (Goble and Hollins, 1993), and this concept led us to hypothesize that if the amplitude of a vibrotactile stimulus was changed continuously, that this modulation would itself impact adaptation. In order to test this idea, two repetitive vibrotactile stimuli were simultaneously delivered to two adjacent finger tips (D2 and D3). In a matching task, a standard stimulus was maintained at constant amplitude (defined as "stationary"), while the amplitude of the test stimuli was increased at a fixed rate (i.e., 10 μm/s; defined as "non-stationary") from a null value up to the level that a subject (n=50) indicated that the two stimuli were perceived to be identical. Changing the standard amplitude yielded results consistent with Weber's Law and changing the modulation rate yielded results that were consistent with our initial hypothesis that faster modulation rates would lead to the non-stationary stimulus as being less adapted. A comparative study, using the above-described method, was conducted with 12 autism subjects who were previously reported to have below normal adaptation metrics (Tannan et al., 2008). The findings of this pilot autism study suggest that rate dependent modulation of vibrotactile stimuli could provide a more sensitive metric of adaptation, as the observations demonstrate a bimodal distribution within the autism spectrum. PMID:21872222

  12. Stimulus devaluation induced by stopping action.

    PubMed

    Wessel, Jan R; O'Doherty, John P; Berkebile, Michael M; Linderman, David; Aron, Adam R

    2014-12-01

    Impulsive behavior in humans partly relates to inappropriate overvaluation of reward-associated stimuli. Hence, it is desirable to develop methods of behavioral modification that can reduce stimulus value. Here, we tested whether one kind of behavioral modification--the rapid stopping of actions in the face of reward-associated stimuli--could lead to subsequent devaluation of those stimuli. We developed a novel paradigm with three consecutive phases: implicit reward learning, a stop-signal task, and an auction procedure. In the learning phase, we associated abstract shapes with different levels of reward. In the stop-signal phase, we paired half those shapes with occasional stop-signals, requiring the rapid stopping of an initiated motor response, while the other half of shapes was not paired with stop signals. In the auction phase, we assessed the subjective value of each shape via willingness-to-pay. In 2 experiments, we found that participants bid less for shapes that were paired with stop-signals compared to shapes that were not. This suggests that the requirement to try to rapidly stop a response decrements stimulus value. Two follow-on control experiments suggested that the result was specifically due to stopping action rather than aversiveness, effort, conflict, or salience associated with stop signals. This study makes a theoretical link between research on inhibitory control and value. It also provides a novel behavioral paradigm with carefully operationalized learning, treatment, and valuation phases. This framework lends itself to both behavioral modification procedures in clinical disorders and research on the neural underpinnings of stimulus devaluation.

  13. Stimulus devaluation induced by stopping action

    PubMed Central

    Wessel, Jan R.; O’Doherty, John P.; Berkebile, Michael M.; Linderman, David; Aron, Adam R.

    2014-01-01

    Impulsive behavior in humans partly relates to inappropriate overvaluation of reward-associated stimuli. Hence, it is desirable to develop methods of behavioral modification that can reduce stimulus value. Here, we tested whether one kind of behavioral modification – the rapid stopping of actions in the face of reward-associated stimuli – could lead to subsequent devaluation of those stimuli. We developed a novel paradigm with three consecutive phases: implicit reward learning, a stop-signal task, and an auction procedure. In the learning phase, we associated abstract shapes with different levels of reward. In the stop-signal phase, we paired half those shapes with occasional stop-signals, requiring the rapid stopping of an initiated motor response, while the other half of shapes was not paired with stop signals. In the auction phase, we assessed the subjective value of each shape via willingness-to-pay. In two experiments, we found that participants bid less for shapes that were paired with stop-signals compared to shapes that were not. This suggests that the requirement to try to rapidly stop a response decrements stimulus value. Two follow-on control experiments suggested that the result was specifically due to stopping action rather than aversiveness, effort, conflict, or salience associated with stop signals. This study makes a theoretical link between research on inhibitory control and value. It also provides a novel behavioral paradigm with carefully operationalized learning, treatment, and valuation phases. This framework lends itself to both behavioral modification procedures in clinical disorders, and research on the neural underpinnings of stimulus devaluation. PMID:25313953

  14. Teaching braille line tracking using stimulus fading.

    PubMed

    Scheithauer, Mindy C; Tiger, Jeffrey H

    2014-01-01

    Line tracking is a prerequisite skill for braille literacy that involves moving one's finger horizontally across a line of braille text and identifying when a line ends so the reader may reset his or her finger on the subsequent line. Current procedures for teaching line tracking are incomplete, because they focus on tracking lines with only small gaps between characters. The current study extended previous line-tracking instruction using stimulus fading to teach tracking across larger gaps. After instruction, all participants showed improvement in line tracking, and 2 of 3 participants met mastery criteria for tracking across extended spaces.

  15. The Elicitation of Vocal Responses from Preschool Children.

    ERIC Educational Resources Information Center

    Champley, Elizabeth Hyne; Andrews, Moya L.

    1993-01-01

    This article discusses the construction of tasks used to elicit vocal responses from preschool children with and without communication disorders. Procedures to elicit valid and reliable responses are proposed, and a sample assessment protocol is presented. (Author/DB)

  16. Effect of multimodal stimulus presentation on recall.

    PubMed

    Kobus, D A; Moses, J D; Bloom, F A

    1994-02-01

    This study was conducted to investigate how the mode of stimulus presentation affects recall in the classroom environment. 289 undergraduates were randomly assigned to one of 7 experimental groups. All subjects were presented the same stimuli in one of 7 possible modes: (1) Printed Word, (2) Spoken Word, (3) Picture, (4) Printed Word + Spoken Word, (5) Picture + Spoken Word, (6) Picture + Printed Word, and (7) Printed Word, Picture + Spoken Word. 30 words, 6 from each of 5 categories, were presented to each group. A new stimulus was presented every 5 sec. Subjects were to recall (in writing) as many stimuli as possible in 5 min. regardless of order. One-way between groups analyses of variance were conducted on recall and cluster index scores. A significant main effect of mode of presentation showed that recall was best for the Picture or multimodal group (Printed Word, Picture + Spoken Word). Groups receiving only the spoken or printed word showed significantly poorer recall than the multimodal groups. No statistically significant differences between groups were found on the cluster index score. It appears that the simultaneous presentation of redundant stimuli in multiple modalities does support the multiple-resource hypothesis by displaying enhanced recall when information is available from multiple attentional resources.

  17. Single stimulus color can modulate vection

    PubMed Central

    Seya, Yasuhiro; Yamaguchi, Megumi; Shinoda, Hiroyuki

    2015-01-01

    In the present study, we investigated the effects of single color on forward and backward vection. The approaching or receding optical flow observed during forward or backward locomotion was simulated by using random dots with changing size, velocity, and disparity. The dots were presented on a black (Experiments 1 and 2) or white background (Experiment 3) in equiluminant colors; namely, white (or gray), red, yellow, green, or blue. The participant's task was to press and hold one of three buttons whenever they felt vection. The three buttons corresponded to the subjective strength of vection: strong, same, and weak relative to vection induced by the standard modulus. In Experiments 1 and 2, the participants were also asked to rate the strength and direction of vection after each trial. In Experiment 3, they rated the visibility and the perceived velocity of dot motion. Experiment 1 showed that the induced vection was stronger for the chromatic than for the achromatic dots. Particularly at low velocity conditions (±10 km/h), the vection induced for red dots was stronger than that for the other colored dots. Experiment 2 showed that the order effects of stimulus presentation could not explain the findings of Experiment 1. Experiment 3's pattern of results was similar to that of Experiment 1, and this suggested that a luminance artifact between color conditions could not account for Experiment 1's findings. These results suggest that a stimulus color can modulate vection even when a single color is added to the optical flow. PMID:25914665

  18. Hospital Clowning as Play Stimulus in Healthcare

    PubMed Central

    Anes, Laura; Obi, Marianne

    2014-01-01

    A serious illness, a chronic medical condition or a hospital bed should not deny any child her/his basic right to play, a right essential for children’s development and general wellbeing. In fact, it is in these frightening and anxious moments that play and the stimulus that it provides can help the most. This article will focus on the impacts and benefits of professional hospital clowning for the wellbeing and recovery process of ill and hospitalized children. Our experience has shown that through interactive play and humor, “clowndoctors” can create an enabling and supportive environment that facilitates children’s adaptation to the hospital setting and improves their acceptance of medical procedures and staff. While moving from bedside to bedside, RED NOSES clowndoctors encourage children’s active participation and support their natural instinct to play, fully including them in the interaction, if the children wish to do so. Therefore, clowndoctor performances offer ill children much needed stimulus, self-confidence and courage, elements fundamental to reducing their vulnerability. In this piece, a special emphasis will be put on the various approaches used by RED NOSES clowndoctors to bond and reach out to children suffering from different medical conditions. PMID:27417485

  19. Quantification of a contact stimulus by diapers

    NASA Astrophysics Data System (ADS)

    Nomata, Takuya; Okuyama, Takeshi; Teraoka, Hiromi; Murakami, Yasuo; Miyazawa, Kiyoshi; Tanaka, Mami

    2009-12-01

    This paper describes a development of a sensor system for measurement of a contact stimulus which diapers give to infants. A polyvinyliden fluoride (PVDF) film and a strain gauge are used as the sensor receptors. The PVDF is a kind of piezoelectric material. The sensor consists of a surface contact layer, a PVDF film, a strain gauge and an aluminum plate. First, in order to investigate the sensor performance, the sensor was located on a silicone plate and the upper part of the sensor was rubbed with an acrylic artificial finger. The finger enabled the measurement to carry out at a constant speed and force. Next, the sensor was attached on an infant dummy and the sensor outputs were measured under conditions with and without diapers. By comparison of the output under two different conditions, it was confirmed that there is a clearly difference between the two conditions. It was found that the developed sensor system has the possibility to quantify a contact stimulus which diapers give infants.

  20. Quantification of a contact stimulus by diapers

    NASA Astrophysics Data System (ADS)

    Nomata, Takuya; Okuyama, Takeshi; Teraoka, Hiromi; Murakami, Yasuo; Miyazawa, Kiyoshi; Tanaka, Mami

    2010-01-01

    This paper describes a development of a sensor system for measurement of a contact stimulus which diapers give to infants. A polyvinyliden fluoride (PVDF) film and a strain gauge are used as the sensor receptors. The PVDF is a kind of piezoelectric material. The sensor consists of a surface contact layer, a PVDF film, a strain gauge and an aluminum plate. First, in order to investigate the sensor performance, the sensor was located on a silicone plate and the upper part of the sensor was rubbed with an acrylic artificial finger. The finger enabled the measurement to carry out at a constant speed and force. Next, the sensor was attached on an infant dummy and the sensor outputs were measured under conditions with and without diapers. By comparison of the output under two different conditions, it was confirmed that there is a clearly difference between the two conditions. It was found that the developed sensor system has the possibility to quantify a contact stimulus which diapers give infants.

  1. Matching-to-Sample and Stimulus-Pairing-Observation Procedures in Stimulus Equivalence: The Effects of Number of Trials and Stimulus Arrangement

    ERIC Educational Resources Information Center

    Kinloch, Jennifer May; McEwan, James Stewart Anderson; Foster, T. Mary

    2013-01-01

    Studies comparing the effectiveness of the stimulus-pairing-observation and matching-to-sample procedures in facilitating equivalence relations have reported conflicting findings. This study compared the effectiveness of these procedures and examined the effect of stimulus arrangement and the number of training trials completed prior to each…

  2. The 3-second auditory conditioned stimulus is a more effective stressor than the 20-second auditory conditioned stimulus in male rats.

    PubMed

    Kiyokawa, Y; Mikami, K; Mikamura, Y; Ishii, A; Takeuchi, Y; Mori, Y

    2015-07-23

    Using fear-conditioning model, we have used a 3-s auditory conditioned stimulus (CS) as a stressor and observed fear and stress responses during a specific experimental period regardless of the presence or absence of the CS. Because the CS was extremely short compared with the experimental period, we observed responses primarily in the absence of the CS. In contrast, most studies in the literature have analyzed responses in the presence of the CS. Therefore, the characteristics of fear and stress responses in the absence of the CS remain to be clarified. To clarify this, we compared the characteristics of fear and stress responses elicited by a 3-s auditory CS with those observed during a 20-s auditory CS. The basolateral complex of the amygdala (BLA), but not the bed nucleus of the stria terminalis (BNST), participated in the fear response elicited by the 3-s CS, whereas both the BLA and BNST were involved in the response observed during the 20-s CS. Additional analyses revealed that the BNST participated in the fear response during the 20-s CS when the CS was paired with a 0.75-mA, but not with a 0.9-mA, foot shock, and to the contextual CS. In addition, the fear response elicited by the 3-s CS was more resistant to extinction than that during the 20-s CS. Finally, the 3-s CS produced more intense freezing and corticosterone secretion than the 20-s CS. On the basis of these characteristics, we conclude that the 3-s auditory CS is a more effective stressor than the 20-s auditory CS. Our findings also suggest that foot shock intensity is an additional determinant in the type of fear response induced by the CS.

  3. Control effects of stimulus paradigms on characteristic firings of parkinsonism

    NASA Astrophysics Data System (ADS)

    Zhang, Honghui; Wang, Qingyun; Chen, Guanrong

    2014-09-01

    Experimental studies have shown that neuron population located in the basal ganglia of parkinsonian primates can exhibit characteristic firings with certain firing rates differing from normal brain activities. Motivated by recent experimental findings, we investigate the effects of various stimulation paradigms on the firing rates of parkinsonism based on the proposed dynamical models. Our results show that the closed-loop deep brain stimulation is superior in ameliorating the firing behaviors of the parkinsonism, and other control strategies have similar effects according to the observation of electrophysiological experiments. In addition, in conformity to physiological experiments, we found that there exists optimal delay of input in the closed-loop GPtrain|M1 paradigm, where more normal behaviors can be obtained. More interestingly, we observed that W-shaped curves of the firing rates always appear as stimulus delay varies. We furthermore verify the robustness of the obtained results by studying three pallidal discharge rates of the parkinsonism based on the conductance-based model, as well as the integrate-and-fire-or-burst model. Finally, we show that short-term plasticity can improve the firing rates and optimize the control effects on parkinsonism. Our conclusions may give more theoretical insight into Parkinson's disease studies.

  4. Electrodermal activity analysis during affective haptic elicitation.

    PubMed

    Greco, Alberto; Valenza, Gaetano; Nardelli, Mimma; Bianchi, Matteo; Lanata, Antonio; Scilingo, Enzo Pasquale

    2015-08-01

    This paper investigates how the autonomic nervous system dynamics, quantified through the analysis of the electrodermal activity (EDA), is modulated according to affective haptic stimuli. Specifically, a haptic display able to convey caress-like stimuli is presented to 32 healthy subjects (16 female). Each stimulus is changed according to six combinations of three velocities and two forces levels of two motors stretching a strip of fabric. Subjects were also asked to score each stimulus in terms of arousal (high/low activation) and valence (pleasant/unpleasant), in agreement with the circumplex model of affect. EDA was processed using a deconvolutive method, separating tonic and phasic components. A statistical analysis was performed in order to identify significant differences in EDA features among force and velocity levels, as well as in their valence and arousal scores. Results show that the simulated caress induced by the haptic display significantly affects the EDA. In detail, the phasic component seems to be inversely related to the valence score. This finding is new and promising, since it can be used, e.g., as an additional cue for haptics design. PMID:26737605

  5. Ensembles of human MTL neurons “jump back in time” in response to a repeated stimulus

    PubMed Central

    Howard, Marc W.; Viskontas, Indre V.; Shankar, Karthik H.; Fried, Itzhak

    2012-01-01

    Episodic memory, which depends critically on the integrity of the medial temporal lobe (MTL), has been described as “mental time travel” in which the rememberer “jumps back in time.” The neural mechanism underlying this ability remains elusive. Mathematical and computational models of performance in episodic memory tasks provide a specific hypothesis regarding the computation that supports such a jump back in time. The models suggest that a representation of temporal context, a representation that changes gradually over macroscopic periods of time, is the cue for episodic recall. According to these models, a jump back in time corresponds to a stimulus recovering a prior state of temporal context. In vivo single-neuron recordings were taken from the human MTL while epilepsy patients distinguished novel from repeated images in a continuous recognition memory task. The firing pattern of the ensemble of MTL neurons showed robust temporal autocorrelation over macroscopic periods of time during performance of the memory task. The gradually-changing part of the ensemble state was causally affected by the visual stimulus being presented. Critically, repetition of a stimulus caused the ensemble to elicit a pattern of activity that resembled the pattern of activity present before the initial presentation of the stimulus. These findings confirm a direct prediction of this class of temporal context models and may be a signature of the mechanism that underlies the experience of episodic memory as mental time travel. PMID:22488671

  6. Viewing Pain and Happy Faces Elicited Similar Changes in Postural Body Sway

    PubMed Central

    Gea, Juan; Muñoz, Miguel A.; Costa, Isis; Ciria, Luís F.; Miranda, José G. V.; Montoya, Pedro

    2014-01-01

    Affective facial expressions are potent social cues that can induce relevant physiological changes, as well as behavioral dispositions in the observer. Previous studies have revealed that angry faces induced significant reductions in body sway as compared with neutral and happy faces, reflecting an avoidance behavioral tendency as freezing. The expression of pain is usually considered an unpleasant stimulus, but also a relevant cue for delivering effective care and social support. Nevertheless, there are few data about behavioral dispositions elicited by the observation of pain expressions in others. The aim of the present research was to evaluate approach–avoidance tendencies by using video recordings of postural body sway when participants were standing and observing facial expressions of pain, happy and neutral. We hypothesized that although pain faces would be rated as more unpleasant than the other faces, they would provoke significant changes in postural body sway as compared to neutral facial expressions. Forty healthy female volunteers (mean age 25) participated in the study. Amplitude of forward movements and backward movements in the anterior-posterior and medial-lateral axes were obtained. Statistical analyses revealed that pain faces were the most unpleasant stimuli, and that both happy and pain faces were more arousing than neutral ones. Happy and pain faces also elicited greater amplitude of body sway in the anterior-posterior axes as compared with neutral faces. In addition, significant positive correlations were found between body sway elicited by pain faces and pleasantness and empathic ratings, suggesting that changes in postural body sway elicited by pain faces might be associated with approach and cooperative behavioral responses. PMID:25093727

  7. Optimal entrainment of heterogeneous noisy neurons

    PubMed Central

    Wilson, Dan; Holt, Abbey B.; Netoff, Theoden I.; Moehlis, Jeff

    2015-01-01

    We develop a methodology to design a stimulus optimized to entrain nonlinear, noisy limit cycle oscillators with uncertain properties. Conditions are derived which guarantee that the stimulus will entrain the oscillators despite these uncertainties. Using these conditions, we develop an energy optimal control strategy to design an efficient entraining stimulus and apply it to numerical models of noisy phase oscillators and to in vitro hippocampal neurons. In both instances, the optimal stimuli outperform other similar but suboptimal entraining stimuli. Because this control strategy explicitly accounts for both noise and inherent uncertainty of model parameters, it could have experimental relevance to neural circuits where robust spike timing plays an important role. PMID:26074762

  8. Antagonist-elicited cannabis withdrawal in humans.

    PubMed

    Gorelick, David A; Goodwin, Robert S; Schwilke, Eugene; Schwope, David M; Darwin, William D; Kelly, Deanna L; McMahon, Robert P; Liu, Fang; Ortemann-Renon, Catherine; Bonnet, Denis; Huestis, Marilyn A

    2011-10-01

    Cannabinoid CB1 receptor antagonists have potential therapeutic benefits, but antagonist-elicited cannabis withdrawal has not been reported in humans. Ten male daily cannabis smokers received 8 days of increasingly frequent 20-mg oral Δ⁹-tetrahydrocannabinol (THC) dosages (40-120 mg/d) around-the-clock to standardize cannabis dependence while residing on a closed research unit. On the ninth day, double-blind placebo or 20- (suggested therapeutic dose) or 40-mg oral rimonabant, a CB1-cannabinoid receptor antagonist, was administered. Cannabis withdrawal signs and symptoms were assessed before and for 23.5 hours after rimonabant. Rimonabant, THC, and 11-hydroxy-THC plasma concentrations were quantified by mass spectrometry. The first 6 subjects received 20-mg rimonabant (1 placebo); the remaining 4 subjects received 40-mg rimonabant (1 placebo). Fourteen subjects enrolled; 10 completed before premature termination because of withdrawal of rimonabant from clinical development. Three of 5 subjects in the 20-mg group, 1 of 3 in the 40-mg group, and none of 2 in the placebo group met the prespecified withdrawal criterion of 150% increase or higher in at least 3 visual analog scales for cannabis withdrawal symptoms within 3 hours of rimonabant dosing. There were no significant associations between visual analog scale, heart rate, or blood pressure changes and peak rimonabant plasma concentration, area-under-the-rimonabant-concentration-by-time curve (0-8 hours), or peak rimonabant/THC or rimonabant/(THC + 11-hydroxy-THC) plasma concentration ratios. In summary, prespecified criteria for antagonist-elicited cannabis withdrawal were not observed at the 20- or 40-mg rimonabant doses. These data do not preclude antagonist-elicited withdrawal at higher rimonabant doses.

  9. Antagonist-elicited cannabis withdrawal in humans.

    PubMed

    Gorelick, David A; Goodwin, Robert S; Schwilke, Eugene; Schwope, David M; Darwin, William D; Kelly, Deanna L; McMahon, Robert P; Liu, Fang; Ortemann-Renon, Catherine; Bonnet, Denis; Huestis, Marilyn A

    2011-10-01

    Cannabinoid CB1 receptor antagonists have potential therapeutic benefits, but antagonist-elicited cannabis withdrawal has not been reported in humans. Ten male daily cannabis smokers received 8 days of increasingly frequent 20-mg oral Δ⁹-tetrahydrocannabinol (THC) dosages (40-120 mg/d) around-the-clock to standardize cannabis dependence while residing on a closed research unit. On the ninth day, double-blind placebo or 20- (suggested therapeutic dose) or 40-mg oral rimonabant, a CB1-cannabinoid receptor antagonist, was administered. Cannabis withdrawal signs and symptoms were assessed before and for 23.5 hours after rimonabant. Rimonabant, THC, and 11-hydroxy-THC plasma concentrations were quantified by mass spectrometry. The first 6 subjects received 20-mg rimonabant (1 placebo); the remaining 4 subjects received 40-mg rimonabant (1 placebo). Fourteen subjects enrolled; 10 completed before premature termination because of withdrawal of rimonabant from clinical development. Three of 5 subjects in the 20-mg group, 1 of 3 in the 40-mg group, and none of 2 in the placebo group met the prespecified withdrawal criterion of 150% increase or higher in at least 3 visual analog scales for cannabis withdrawal symptoms within 3 hours of rimonabant dosing. There were no significant associations between visual analog scale, heart rate, or blood pressure changes and peak rimonabant plasma concentration, area-under-the-rimonabant-concentration-by-time curve (0-8 hours), or peak rimonabant/THC or rimonabant/(THC + 11-hydroxy-THC) plasma concentration ratios. In summary, prespecified criteria for antagonist-elicited cannabis withdrawal were not observed at the 20- or 40-mg rimonabant doses. These data do not preclude antagonist-elicited withdrawal at higher rimonabant doses. PMID:21869692

  10. Decoding Subjective Intensity of Nociceptive Pain from Pre-stimulus and Post-stimulus Brain Activities

    PubMed Central

    Tu, Yiheng; Tan, Ao; Bai, Yanru; Hung, Yeung Sam; Zhang, Zhiguo

    2016-01-01

    Pain is a highly subjective experience. Self-report is the gold standard for pain assessment in clinical practice, but it may not be available or reliable in some populations. Neuroimaging data, such as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), have the potential to be used to provide physiology-based and quantitative nociceptive pain assessment tools that complements self-report. However, existing neuroimaging-based nociceptive pain assessments only rely on the information in pain-evoked brain activities, but neglect the fact that the perceived intensity of pain is also encoded by ongoing brain activities prior to painful stimulation. Here, we proposed to use machine learning algorithms to decode pain intensity from both pre-stimulus ongoing and post-stimulus evoked brain activities. Neural features that were correlated with intensity of laser-evoked nociceptive pain were extracted from high-dimensional pre- and post-stimulus EEG and fMRI activities using partial least-squares regression (PLSR). Further, we used support vector machine (SVM) to predict the intensity of pain from pain-related time-frequency EEG patterns and BOLD-fMRI patterns. Results showed that combining predictive information in pre- and post-stimulus brain activities can achieve significantly better performance in classifying high-pain and low-pain and in predicting the rating of perceived pain than only using post-stimulus brain activities. Therefore, the proposed pain prediction method holds great potential in basic research and clinical applications. PMID:27148029

  11. Decoding Subjective Intensity of Nociceptive Pain from Pre-stimulus and Post-stimulus Brain Activities.

    PubMed

    Tu, Yiheng; Tan, Ao; Bai, Yanru; Hung, Yeung Sam; Zhang, Zhiguo

    2016-01-01

    Pain is a highly subjective experience. Self-report is the gold standard for pain assessment in clinical practice, but it may not be available or reliable in some populations. Neuroimaging data, such as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), have the potential to be used to provide physiology-based and quantitative nociceptive pain assessment tools that complements self-report. However, existing neuroimaging-based nociceptive pain assessments only rely on the information in pain-evoked brain activities, but neglect the fact that the perceived intensity of pain is also encoded by ongoing brain activities prior to painful stimulation. Here, we proposed to use machine learning algorithms to decode pain intensity from both pre-stimulus ongoing and post-stimulus evoked brain activities. Neural features that were correlated with intensity of laser-evoked nociceptive pain were extracted from high-dimensional pre- and post-stimulus EEG and fMRI activities using partial least-squares regression (PLSR). Further, we used support vector machine (SVM) to predict the intensity of pain from pain-related time-frequency EEG patterns and BOLD-fMRI patterns. Results showed that combining predictive information in pre- and post-stimulus brain activities can achieve significantly better performance in classifying high-pain and low-pain and in predicting the rating of perceived pain than only using post-stimulus brain activities. Therefore, the proposed pain prediction method holds great potential in basic research and clinical applications. PMID:27148029

  12. Eliciting promises from children reduces cheating.

    PubMed

    Heyman, Gail D; Fu, Genyue; Lin, Jianyan; Qian, Miao K; Lee, Kang

    2015-11-01

    Widespread cheating can undermine rules that are necessary for maintaining social order. Preventing cheating can be a challenge, especially with regard to children, who as a result of their limited executive function skills may have particular difficulty with resisting temptation to cheat. We examined one approach designed to help children resist this temptation: eliciting a verbal commitment to not cheat. We tested 4- to 7-year-olds (total N = 330) and found that starting at 5 years of age, a verbal commitment to not cheat led to a substantial reduction in cheating. The results suggest that verbal commitments can be used to help children overcome temptations and comply with rules.

  13. Isolated sleep paralysis elicited by sleep interruption.

    PubMed

    Takeuchi, T; Miyasita, A; Sasaki, Y; Inugami, M; Fukuda, K

    1992-06-01

    We elicited isolated sleep paralysis (ISP) from normal subjects by a nocturnal sleep interruption schedule. On four experimental nights, 16 subjects had their sleep interrupted for 60 minutes by forced awakening at the time when 40 minutes of nonrapid eye movement (NREM) sleep had elapsed from the termination of rapid eye movement (REM) sleep in the first or third sleep cycle. This schedule produced a sleep onset REM period (SOREMP) after the interruption at a high rate of 71.9%. We succeeded in eliciting six episodes of ISP in the sleep interruptions performed (9.4%). All episodes of ISP except one occurred from SOREMP, indicating a close correlation between ISP and SOREMP. We recorded verbal reports about ISP experiences and recorded the polysomnogram (PSG) during ISP. All of the subjects with ISP experienced inability to move and were simultaneously aware of lying in the laboratory. All but one reported auditory/visual hallucinations and unpleasant emotions. PSG recordings during ISP were characterized by a REM/W stage dissociated state, i.e. abundant alpha electroencephalographs and persistence of muscle atonia shown by the tonic electromyogram. Judging from the PSG recordings, ISP differs from other dissociated states such as lucid dreaming, nocturnal panic attacks and REM sleep behavior disorders. We compare some of the sleep variables between ISP and non-ISP nights. We also discuss the similarities and differences between ISP and sleep paralysis in narcolepsy. PMID:1621022

  14. Isolated sleep paralysis elicited by sleep interruption.

    PubMed

    Takeuchi, T; Miyasita, A; Sasaki, Y; Inugami, M; Fukuda, K

    1992-06-01

    We elicited isolated sleep paralysis (ISP) from normal subjects by a nocturnal sleep interruption schedule. On four experimental nights, 16 subjects had their sleep interrupted for 60 minutes by forced awakening at the time when 40 minutes of nonrapid eye movement (NREM) sleep had elapsed from the termination of rapid eye movement (REM) sleep in the first or third sleep cycle. This schedule produced a sleep onset REM period (SOREMP) after the interruption at a high rate of 71.9%. We succeeded in eliciting six episodes of ISP in the sleep interruptions performed (9.4%). All episodes of ISP except one occurred from SOREMP, indicating a close correlation between ISP and SOREMP. We recorded verbal reports about ISP experiences and recorded the polysomnogram (PSG) during ISP. All of the subjects with ISP experienced inability to move and were simultaneously aware of lying in the laboratory. All but one reported auditory/visual hallucinations and unpleasant emotions. PSG recordings during ISP were characterized by a REM/W stage dissociated state, i.e. abundant alpha electroencephalographs and persistence of muscle atonia shown by the tonic electromyogram. Judging from the PSG recordings, ISP differs from other dissociated states such as lucid dreaming, nocturnal panic attacks and REM sleep behavior disorders. We compare some of the sleep variables between ISP and non-ISP nights. We also discuss the similarities and differences between ISP and sleep paralysis in narcolepsy.

  15. Novelty, stimulus control, and operant variability

    PubMed Central

    Shahan, Timothy A.; Chase, Philip N.

    2002-01-01

    Although behavior analysis has been criticized for failure to account for response novelty, many common behavior-analytic concepts and processes (e.g., selectionism, the operant, reinforcement, and stimulus control) assume variability both in the environment and in behavior. The importance of the relation between variability and novelty, particularly for verbal behavior, is discussed, and concepts used to account for novel behavior are examined. Experimental findings also are reviewed that suggest that variability in behavior can come under discriminative control, and these findings are applied to describe novel instances of behavior that may arise during problem solving. We conclude that variations provided and selected by the terms of the three-term contingency are powerful means for understanding novel behavior. PMID:22478385

  16. Hippocampal culture stimulus with 4-megahertz ultrasound

    NASA Astrophysics Data System (ADS)

    Muratore, Robert; LaManna, Justine K.; Lamprecht, Michael R.; Morrison, Barclay, III

    2012-10-01

    Among current modalities, ultrasound uniquely offers both millisecond and millimeter accuracy in noninvasively stimulating brain tissue. In addition, by sweeping the ultrasound beam within the refractory period of the neuronal tissue, ultrasonic neuromodulation can be adapted to target extended or multiply connected regions with quasi-simultaneity. Towards the development of this safe brain stimulus technique, the response of rat hippocampal cultures to ultrasound was investigated. Hippocampal slices, 0.4-mm thick, were obtained from 8-day old Sprague Dawley rats and cultured for 6 days. The in vitro cultures were exposed to multiple 100-ms 4.04-MHz ultrasound pulses from a 42-mm diameter, 90-mm spherical cap transducer. Peak pressure ranged from 0 through about 77 kPa. Responses in the form of electrical potentials from a sixty channel electrode array were digitized and recorded. The DG and CA1 regions of the hippocampus exhibited similar ultrasonically-evoked field potentials.

  17. Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Squires, N.; Galambos, R.

    1975-01-01

    Short latency (under 10 msec) evoked responses elicited by bursts of white noise were recorded from the scalp of human subjects. Response alterations produced by changes in the noise burst duration (on-time) inter-burst interval (off-time), and onset and offset shapes are reported and evaluated. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise-time but was unaffected by changes in fall-time. The amplitude of wave V was insensitive to changes in signal rise-and-fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It is concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

  18. Stimulus-induced rhythmic, periodic, or ictal discharges (SIRPIDs): an intriguing EEG phenomenon.

    PubMed

    Silveira, Mariana Ribeiro Marcondes da; Andrade, Joaquina; Garzon, Eliana

    2013-12-01

    SIRPIDs, an acronym for stimulus-induced rhythmic, periodic, or ictal discharges, were first named in 2004. This is a pattern observed in continuous electroencephalogram (CEEG) consistently elicited by stimulation in comatose patients. The pathophysiology of SIRPIDs probably involves dysregulation of subcortico-cortical projections, particularly thalamocortical circuit, in a markedly abnormal brain with hyperexci-table cortex. This may explain some studies found an association of prolonged periodic epileptiform discharges (PEDs) activity and a higher incidence of concurrent electrographic seizures and SIRPIDs. An association of SIRPIDs and poor prognosis has already been described. However, it is not yet possible to assert whether these discharges can cause neuronal injury or if they are simply a marker of severe brain injury. Objective of this paper is to review clinical relevance and pathophysiology of SIRPIDs, as well as its role as a brain response in the critically ill patient.

  19. Minding the PS, queues, and PXQs: Uniformity of semantic processing across multiple stimulus types

    PubMed Central

    Laszlo, Sarah; Federmeier, Kara D.

    2009-01-01

    An assumption in the reading literature is that access to semantics is gated by stimulus properties such as orthographic regularity or familiarity. In the electrophysiological domain, this assumption has led to a debate about the features necessary to initiate semantic processing as indexed by theN400 event-related potential (ERP) component. To examine this, we recorded ERPs to sentences with endings that were familiar and legal (words), familiar and illegal (acronyms), or unfamiliar and illegal (consonant or vowel strings). N400 congruency effects (reduced negativity to expected relative to unexpected endings) were observed for words and acronyms; these were identical in size, timing, and scalp distribution. Notably, clear N400 potentials were also elicited by unfamiliar, illegal strings, suggesting that, at least in a verbal context, semantic access may be attempted for any letter string, regardless of familiarity or regularity. PMID:18221447

  20. Craving, Cue Reactivity, and Stimulus Control Among Early-Stage Young Smokers: Effects of Smoking Intensity and Gender

    PubMed Central

    2014-01-01

    Introduction: Smoking initiation usually begins in adolescence, but how and for whom nicotine dependence emerges during this period is unclear. The cue-reactivity paradigm is well suited to examine one marker of dependence: craving-related stimulus control, i.e., the ability of environmental cues to elicit craving to smoke. This study examined the effects of both level of smoking involvement (daily vs. occasional smoking) and gender on reactivity to both smoking and alcohol cues. Methods: Young (age range 16–20; 42% female) daily (n = 55) and occasional (n = 52) smokers were exposed to each of three counterbalanced cues: (a) in vivo smoking (e.g., sight, smell, lighting of cigarette), (b) alcohol (e.g., opening, pouring, and smell of preferred beverage), and (c) neutral cue. Results: Daily smokers exhibited higher levels of tonic (i.e., noncue-elicited) craving than did occasional smokers. Both groups showed significant increases in craving in response to cues (i.e., cue-elicited craving), with little evidence that cue-elicited craving differed between groups. Females were more cue reactive to both the alcohol and smoking cues than males, particularly for the positively reinforced aspects of smoking (i.e., hedonic craving). There were no gender × group interaction effects in response to either the alcohol or the smoking cue. Conclusions: Findings show the presence of cue-elicited craving even among occasional smokers and are consistent with literature demonstrating heightened sensitivity to environmental cues among females. Cue-elicited craving may be one mechanism that contributes to the maintenance of smoking behavior and perhaps to the development of nicotine dependence within early stage smokers. PMID:24042699

  1. Spatiotemporal Dynamics of Cortical Representations during and after Stimulus Presentation.

    PubMed

    van de Nieuwenhuijzen, Marieke E; van den Borne, Eva W P; Jensen, Ole; van Gerven, Marcel A J

    2016-01-01

    Visual perception is a spatiotemporally complex process. In this study, we investigated cortical dynamics during and after stimulus presentation. We observed that visual category information related to the difference between faces and objects became apparent in the occipital lobe after 63 ms. Within the next 110 ms, activation spread out to include the temporal lobe before returning to residing mainly in the occipital lobe again. After stimulus offset, a peak in information was observed, comparable to the peak after stimulus onset. Moreover, similar processes, albeit not identical, seemed to underlie both peaks. Information about the categorical identity of the stimulus remained present until 677 ms after stimulus offset, during which period the stimulus had to be retained in working memory. Activation patterns initially resembled those observed during stimulus presentation. After about 200 ms, however, this representation changed and class-specific activity became more equally distributed over the four lobes. These results show that, although there are common processes underlying stimulus representation both during and after stimulus presentation, these representations change depending on the specific stage of perception and maintenance. PMID:27242453

  2. Parallel and orthogonal stimulus in ultradiluted neural networks.

    PubMed

    Sobral, G A; Vieira, V M; Lyra, M L; da Silva, C R

    2006-10-01

    Extending a model due to Derrida, Gardner, and Zippelius, we have studied the recognition ability of an extreme and asymmetrically diluted version of the Hopfield model for associative memory by including the effect of a stimulus in the dynamics of the system. We obtain exact results for the dynamic evolution of the average network superposition. The stimulus field was considered as proportional to the overlapping of the state of the system with a particular stimulated pattern. Two situations were analyzed, namely, the external stimulus acting on the initialization pattern (parallel stimulus) and the external stimulus acting on a pattern orthogonal to the initialization one (orthogonal stimulus). In both cases, we obtained the complete phase diagram in the parameter space composed of the stimulus field, thermal noise, and network capacity. Our results show that the system improves its recognition ability for parallel stimulus. For orthogonal stimulus two recognition phases emerge with the system locking at the initialization or stimulated pattern. We confront our analytical results with numerical simulations for the noiseless case T = 0. PMID:17155143

  3. The influence of stimulus duration on odor perception.

    PubMed

    Frasnelli, Johannes; Wohlgemuth, Christiane; Hummel, Thomas

    2006-10-01

    Although different parameters are known to alter the shape of olfactory event related potentials (ERP), ERP parameters are generally thought to be independent from stimulus duration. Evidence from recent studies investigating trigeminal ERP indicates that this may not be true. Aim of the present study was to investigate the relationship of stimulus duration and ERP. A total of 20 young healthy subjects participated. Subjects were investigated on 5 occasions on 5 different days. ERP were recorded to olfactory stimuli of two different concentrations and 3 different durations (100 ms, 200 ms, 300 ms). In two sessions olfactory ERP to PEA were recorded, in another two sessions H2S was applied. During the same sessions, intensity ratings were recorded. In the fifth session, subjects were asked to rate the duration of H2S stimuli and PEA stimuli. Whereas at weak stimulus concentrations no effect of stimulus duration could be observed, there was a clear effect of "duration" in ERP amplitudes following stimuli with higher concentrations: the longer the stimulus duration the larger the ERP amplitudes. No effect was found on ERP latencies. With regard to intensity ratings, strong stimuli and longer lasting stimuli lead to higher ratings. Similarly, ratings of stimulus duration were dependent from stimulus concentration and stimulus duration. Results of the present study showed that similar to trigeminal ERP, information about stimulus duration is encoded in olfactory ERP, mainly in amplitudes.

  4. Spatiotemporal Dynamics of Cortical Representations during and after Stimulus Presentation

    PubMed Central

    van de Nieuwenhuijzen, Marieke E.; van den Borne, Eva W. P.; Jensen, Ole; van Gerven, Marcel A. J.

    2016-01-01

    Visual perception is a spatiotemporally complex process. In this study, we investigated cortical dynamics during and after stimulus presentation. We observed that visual category information related to the difference between faces and objects became apparent in the occipital lobe after 63 ms. Within the next 110 ms, activation spread out to include the temporal lobe before returning to residing mainly in the occipital lobe again. After stimulus offset, a peak in information was observed, comparable to the peak after stimulus onset. Moreover, similar processes, albeit not identical, seemed to underlie both peaks. Information about the categorical identity of the stimulus remained present until 677 ms after stimulus offset, during which period the stimulus had to be retained in working memory. Activation patterns initially resembled those observed during stimulus presentation. After about 200 ms, however, this representation changed and class-specific activity became more equally distributed over the four lobes. These results show that, although there are common processes underlying stimulus representation both during and after stimulus presentation, these representations change depending on the specific stage of perception and maintenance. PMID:27242453

  5. Chlamydial disease pathogenesis. Ocular hypersensitivity elicited by a genus-specific 57-kD protein

    PubMed Central

    1989-01-01

    Recurrent or persistent infections with Chlamydia trachomatis are thought to provide the antigenic stimulus for the chronic inflammation associated with blinding trachoma. We used the guinea pig model of inclusion conjunctivitis to identify chlamydial antigens that may be involved in this deleterious immune response. We purified from chlamydial elementary bodies a genus-specific 57-kD protein that elicited an ocular hypersensitivity response when placed topically onto the conjunctiva of ocular immune guinea pigs. This response was characterized by a predominantly mononuclear macrophage and lymphocyte cellular infiltrate of the submucosal epithelium. The clinical and histological findings were consistent with those of a delayed hypersensitivity response. These data demonstrated that the 57-kD chlamydial protein was a potent stimulator of ocular delayed hypersensitivity. Our findings may be critical to understanding the pathogenesis of the debilitating chlamydial diseases associated with chronic inflammation, such as trachoma and many urogenital syndromes. PMID:2926323

  6. Classical Conditioning Components of the Orienting Reflex to Words Using Innocuous and Noxious Unconditioned Stimuli Under Different Conditioned Stimulus-Unconditioned Stimulus Intervals

    ERIC Educational Resources Information Center

    Maltzman, Irving; And Others

    1977-01-01

    Concerns the examination of conditioned stimulus--unconditioned stimulus (CS--UCS) intervals of different lengths. Demonstrates the feasibility of using a forewarned reaction time procedure with an innocuous imperative stimulus for the investigation of classical conditioning. (Editor/RK)

  7. Stimulus-Stimulus Pairing to Increase Vocalizations in Children with Language Delays: a Review.

    PubMed

    Shillingsburg, M Alice; Hollander, Diane L; Yosick, Rachel N; Bowen, Crystal; Muskat, Lori R

    2015-10-01

    Stimulus-stimulus pairing (SSP) is a procedure used to increase vocalizations in children with significant language delays. However, results from studies that have examined the effectiveness of SSP have been discrepant. The following review of the literature summarizes the results from 13 experiments published between 1996 and 2014 that used this procedure with children with language delays. Studies were analyzed across various participant and procedural variables, and an effect size estimate (nonoverlap of all pairs) was calculated for a portion of the participants in the studies reviewed. Results indicated an overall moderate intervention effect for SSP of speech sounds. Recommendations are provided for future researchers about information to report and potential avenues for future studies. PMID:27606213

  8. Live predators, robots, and computer-animated images elicit differential avoidance responses in zebrafish.

    PubMed

    Ladu, Fabrizio; Bartolini, Tiziana; Panitz, Sarah G; Chiarotti, Flavia; Butail, Sachit; Macrì, Simone; Porfiri, Maurizio

    2015-06-01

    Emotional disturbances constitute a major health issue affecting a considerable portion of the population in western countries. In this context, animal models offer a relevant tool to address the underlying biological determinants and to screen novel therapeutic strategies. While rodents have traditionally constituted the species of choice, zebrafish are now becoming a viable alternative. As zebrafish gain momentum in biomedical sciences, considerable efforts are being devoted to developing high-throughput behavioral tests. Here, we present a comparative study of zebrafish behavioral response to fear-evoking stimuli offered via three alternative methodologies. Specifically, in a binary-choice test, we exposed zebrafish to an allopatric predator Astronotus ocellatus, presented in the form of a live subject, a robotic replica, and a computer-animated image. The robot's design and operation were inspired by the morphology and tail-beat motion of its live counterpart, thereby offering a consistent three-dimensional stimulus to focal fish. The computer-animated image was also designed after the live subject to replicate its appearance. We observed that differently from computer-animated images, both the live predator and its robotic replica elicited robust avoidance response in zebrafish. In addition, in response to the robot, zebrafish exhibited increased thrashing behavior, which is considered a valid indicator of fear. Finally, inter-individual response to a robotic stimulus is more consistent than that shown in response to live stimuli and animated images, thereby increasing experimental statistical power. Our study supports the view that robotic stimuli can constitute a promising experimental tool to elicit targeted behavioral responses in zebrafish.

  9. Compound stimuli in emergent stimulus relations: Extending the scope of stimulus equivalence

    PubMed Central

    Markham, Michael R.; Dougher, Michael J.

    1993-01-01

    Three experiments were conducted to investigate stimulus relations that might emerge when college students are taught relations between compound sample stimuli and unitary comparison stimuli using match-to-sample procedures. In Experiment 1, subjects were taught nine AB-C stimulus relations, then tested for the emergence of 18 AC-B and BC-A relations. All subjects showed the emergence of all tested relations. Twelve subjects participated in Experiment 2. Six subjects were taught nine AB-C relations and were then tested for symmetrical (C-AB) relations. Six subjects were taught nine AB-C and three C-D relations and were then tested for nine AB-D (transitive) relations. Five of 6 subjects demonstrated the emergence of symmetrical relations, and 6 subjects showed the emergence of transitivity. In Experiment 3, 5 college students were taught nine AB-C and three C-D relations and were then tested for nine equivalence (D-AB) relations and 18 AD-B and BD-A relations. Three subjects demonstrated all tested relations. One subject demonstrated the AD-B and BD-A relations but not the D-AB relations. One subject did not respond systematically during testing. The results of these experiments extend stimulus equivalence research to more complex cases. PMID:16812718

  10. Assessing pragmatic skills in elicited production.

    PubMed

    de Villiers, Peter

    2004-02-01

    In developing a test of pragmatic skills for children ages 4 to 9 years, we focused on a number of functional language skills that are important for children's success in early schooling and for the development of fluent reading and writing. They included (1) wh-question asking, (2) communicative role taking, (3) linking events in a cohesive narrative, and (4) articulating the mental states of the characters in a story. All of the proposed items provide specific referential support and pragmatic motivation for the forms and content to be produced by the child. The pictured materials and elicitation prompts constrain the range of appropriate utterances, so the children's productions are more easily scored than an open-ended spontaneous speech sample. All tasks described show a clear developmental trend, a clear separation between the performance of typically developing and language-impaired children, and no performance differences between African American English- and Mainstream American English-speaking children.

  11. Hindlimb unloading elicits anhedonia and sympathovagal imbalance.

    PubMed

    Moffitt, Julia A; Grippo, Angela J; Beltz, Terry G; Johnson, Alan Kim

    2008-10-01

    The hindlimb-unloaded (HU) rat model elicits cardiovascular deconditioning and simulates the physiological adaptations to microgravity or prolonged bed rest in humans. Although psychological deficits have been documented following bed rest and spaceflight in humans, few studies have explored the psychological effects of cardiovascular deconditioning in animal models. Given the bidirectional link established between cardiac autonomic imbalance and psychological depression in both humans and in animal models, we hypothesized that hindlimb unloading would elicit an alteration in sympathovagal tone and behavioral indexes of psychological depression. Male, Sprague-Dawley rats confined to 14 days of HU displayed anhedonia (a core feature of human depression) compared with casted control (CC) animals evidenced by reduced sucrose preference (CC: 81 +/- 2.9% baseline vs. HU: 58 +/- 4.5% baseline) and reduced (rightward shift) operant responding for rewarding electrical brain stimulation (CC: 4.4 +/- 0.3 muA vs. 7.3 +/- 1.0 muA). Cardiac autonomic blockade revealed elevated sympathetic [CC: -54 +/- 14.1 change in (Delta) beats/min vs. HU: -118 +/- 7.6 Delta beats/min] and reduced parasympathetic (CC: 45 +/- 11.8 Delta beats/min vs. HU: 8 +/- 7.3 Delta beats/min) cardiac tone in HU rats. Heart rate variability was reduced (CC: 10 +/- 1.4 ms vs. HU: 7 +/- 0.7 ms), and spectral analysis of blood pressure indicated loss of total, low-, and high-frequency power, consistent with attenuated baroreflex function. These data indicate that cardiovascular deconditioning results in sympathovagal imbalance and behavioral signs consistent with psychological depression. These findings further elucidate the pathophysiological link between cardiovascular diseases and affective disorders.

  12. Anthropogenic Radio-Frequency Electromagnetic Fields Elicit Neuropathic Pain in an Amputation Model.

    PubMed

    Black, Bryan; Granja-Vazquez, Rafael; Johnston, Benjamin R; Jones, Erick; Romero-Ortega, Mario

    2016-01-01

    Anecdotal and clinical reports have suggested that radio-frequency electromagnetic fields (RF EMFs) may serve as a trigger for neuropathic pain. However, these reports have been widely disregarded, as the epidemiological effects of electromagnetic fields have not been systematically proven, and are highly controversial. Here, we demonstrate that anthropogenic RF EMFs elicit post-neurotomy pain in a tibial neuroma transposition model. Behavioral assays indicate a persistent and significant pain response to RF EMFs when compared to SHAM surgery groups. Laser thermometry revealed a transient skin temperature increase during stimulation. Furthermore, immunofluorescence revealed an increased expression of temperature sensitive cation channels (TRPV4) in the neuroma bulb, suggesting that RF EMF-induced pain may be due to cytokine-mediated channel dysregulation and hypersensitization, leading to thermal allodynia. Additional behavioral assays were performed using an infrared heating lamp in place of the RF stimulus. While thermally-induced pain responses were observed, the response frequency and progression did not recapitulate the RF EMF effects. In vitro calcium imaging experiments demonstrated that our RF EMF stimulus is sufficient to directly contribute to the depolarization of dissociated sensory neurons. Furthermore, the perfusion of inflammatory cytokine TNF-α resulted in a significantly higher percentage of active sensory neurons during RF EMF stimulation. These results substantiate patient reports of RF EMF-pain, in the case of peripheral nerve injury, while confirming the public and scientific consensus that anthropogenic RF EMFs engender no adverse sensory effects in the general population. PMID:26760033

  13. Anthropogenic Radio-Frequency Electromagnetic Fields Elicit Neuropathic Pain in an Amputation Model.

    PubMed

    Black, Bryan; Granja-Vazquez, Rafael; Johnston, Benjamin R; Jones, Erick; Romero-Ortega, Mario

    2016-01-01

    Anecdotal and clinical reports have suggested that radio-frequency electromagnetic fields (RF EMFs) may serve as a trigger for neuropathic pain. However, these reports have been widely disregarded, as the epidemiological effects of electromagnetic fields have not been systematically proven, and are highly controversial. Here, we demonstrate that anthropogenic RF EMFs elicit post-neurotomy pain in a tibial neuroma transposition model. Behavioral assays indicate a persistent and significant pain response to RF EMFs when compared to SHAM surgery groups. Laser thermometry revealed a transient skin temperature increase during stimulation. Furthermore, immunofluorescence revealed an increased expression of temperature sensitive cation channels (TRPV4) in the neuroma bulb, suggesting that RF EMF-induced pain may be due to cytokine-mediated channel dysregulation and hypersensitization, leading to thermal allodynia. Additional behavioral assays were performed using an infrared heating lamp in place of the RF stimulus. While thermally-induced pain responses were observed, the response frequency and progression did not recapitulate the RF EMF effects. In vitro calcium imaging experiments demonstrated that our RF EMF stimulus is sufficient to directly contribute to the depolarization of dissociated sensory neurons. Furthermore, the perfusion of inflammatory cytokine TNF-α resulted in a significantly higher percentage of active sensory neurons during RF EMF stimulation. These results substantiate patient reports of RF EMF-pain, in the case of peripheral nerve injury, while confirming the public and scientific consensus that anthropogenic RF EMFs engender no adverse sensory effects in the general population.

  14. The Elicitation of Audiovisual Steady-State Responses: Multi-Sensory Signal Congruity and Phase Effects

    PubMed Central

    Rhone, Ariane E.; Idsardi, William J.; Simon, Jonathan Z.; Poeppel, David

    2013-01-01

    Most ecologically natural sensory inputs are not limited to a single modality. While it is possible to use real ecological materials as experimental stimuli to investigate the neural basis of multi-sensory experience, parametric control of such tokens is limited. By using artificial bimodal stimuli composed of approximations to ecological signals, we aim to observe the interactions between putatively relevant stimulus attributes. Here we use MEG as an electrophysiological tool and employ as a measure the steady-state response (SSR), an experimental paradigm typically applied to unimodal signals. In this experiment we quantify the responses to a bimodal audio-visual signal with different degrees of temporal (phase) congruity, focusing on stimulus properties critical to audiovisual speech. An amplitude modulated auditory signal (‘pseudo-speech’) is paired with a radius-modulated ellipse (‘pseudo-mouth’), with the envelope of low-frequency modulations occurring in phase or at offset phase values across modalities. We observe (i) that it is possible to elicit an SSR to bimodal signals; (ii) that bimodal signals exhibit greater response power than unimodal signals; and (iii) that the SSR power at specific harmonics and sensors differentially reflects the congruity between signal components. Importantly, we argue that effects found at the modulation frequency and second harmonic reflect differential aspects of neural coding of multisensory signals. The experimental paradigm facilitates a quantitative characterization of properties of multi-sensory speech and other bimodal computations. PMID:21380858

  15. Visual stimuli that elicit appetitive behaviors in three morphologically distinct species of praying mantis.

    PubMed

    Prete, Frederick R; Komito, Justin L; Dominguez, Salina; Svenson, Gavin; López, LeoLin Y; Guillen, Alex; Bogdanivich, Nicole

    2011-09-01

    We assessed the differences in appetitive responses to visual stimuli by three species of praying mantis (Insecta: Mantodea), Tenodera aridifolia sinensis, Mantis religiosa, and Cilnia humeralis. Tethered, adult females watched computer generated stimuli (erratically moving disks or linearly moving rectangles) that varied along predetermined parameters. Three responses were scored: tracking, approaching, and striking. Threshold stimulus size (diameter) for tracking and striking at disks ranged from 3.5 deg (C. humeralis) to 7.8 deg (M. religiosa), and from 3.3 deg (C. humeralis) to 11.7 deg (M. religiosa), respectively. Unlike the other species which struck at disks as large as 44 deg, T. a. sinensis displayed a preference for 14 deg disks. Disks moving at 143 deg/s were preferred by all species. M. religiosa exhibited the most approaching behavior, and with T. a. sinensis distinguished between rectangular stimuli moving parallel versus perpendicular to their long axes. C. humeralis did not make this distinction. Stimulus sizes that elicited the target behaviors were not related to mantis size. However, differences in compound eye morphology may be related to species differences: C. humeralis' eyes are farthest apart, and it has an apparently narrower binocular visual field which may affect retinal inputs to movement-sensitive visual interneurons. PMID:21553126

  16. Anthropogenic Radio-Frequency Electromagnetic Fields Elicit Neuropathic Pain in an Amputation Model

    PubMed Central

    Jones, Erick; Romero-Ortega, Mario

    2016-01-01

    Anecdotal and clinical reports have suggested that radio-frequency electromagnetic fields (RF EMFs) may serve as a trigger for neuropathic pain. However, these reports have been widely disregarded, as the epidemiological effects of electromagnetic fields have not been systematically proven, and are highly controversial. Here, we demonstrate that anthropogenic RF EMFs elicit post-neurotomy pain in a tibial neuroma transposition model. Behavioral assays indicate a persistent and significant pain response to RF EMFs when compared to SHAM surgery groups. Laser thermometry revealed a transient skin temperature increase during stimulation. Furthermore, immunofluorescence revealed an increased expression of temperature sensitive cation channels (TRPV4) in the neuroma bulb, suggesting that RF EMF-induced pain may be due to cytokine-mediated channel dysregulation and hypersensitization, leading to thermal allodynia. Additional behavioral assays were performed using an infrared heating lamp in place of the RF stimulus. While thermally-induced pain responses were observed, the response frequency and progression did not recapitulate the RF EMF effects. In vitro calcium imaging experiments demonstrated that our RF EMF stimulus is sufficient to directly contribute to the depolarization of dissociated sensory neurons. Furthermore, the perfusion of inflammatory cytokine TNF-α resulted in a significantly higher percentage of active sensory neurons during RF EMF stimulation. These results substantiate patient reports of RF EMF-pain, in the case of peripheral nerve injury, while confirming the public and scientific consensus that anthropogenic RF EMFs engender no adverse sensory effects in the general population. PMID:26760033

  17. Effects of Stimulus-Driven and Goal-Directed Attention on Prepulse Inhibition of Brain Oscillations

    PubMed Central

    Annic, Agnès; Bourriez, Jean-Louis; Delval, Arnaud; Bocquillon, Perrine; Trubert, Claire; Derambure, Philippe; Dujardin, Kathy

    2016-01-01

    Objective: Prepulse inhibition (PPI) is an operational measure of sensory gating. PPI of cortical response to a startling pulse is known to be modulated by attention. With a time-frequency analysis, we sought to determine whether goal-directed and stimulus-driven attention differentially modulate inhibition of cortical oscillations elicited by a startling pulse. Methods: An electroencephalogram (EEG) was recorded in 26 healthy controls performing an active acoustic PPI paradigm. Startling stimuli were presented alone or either 400 or 1000 ms after one of three types of visual prepulse: to-be-attended (goal-directed attention), unexpected (stimulus-driven attention) or to-be-ignored (non-focused attention). We calculated the percentage PPI for the auditory event-related spectral perturbation (ERSP) of theta (4–7 Hz), alpha (8–12 Hz), beta1 (13–20 Hz) and beta2 (20–30 Hz) oscillations and changes in inter-trial coherence (ITC), a measure of phase synchronization of electroencephalographic activity. Results: At 400 ms: (i) PPI of the ERSP of alpha, theta and beta1 oscillation was greater after an unexpected and a to-be-attended prepulse than after a to-be-ignored prepulse; and (ii) PPI of beta2 oscillations was greater after a to-be-attended than a to-be-ignored prepulse. At 1000 ms: (i) PPI of alpha oscillations was greater after an unexpected and a to-be-attended prepulse than after a to-be-ignored prepulse; and (ii) PPI of beta1 oscillations was greater after a to-be-attended than a to-be-ignored prepulse. The ITC values did not vary according to the type of prepulse. Conclusions: In an active PPI paradigm, stimulus-driven and goal-directed attention each have differential effects on the modulation of cortical oscillations. PMID:27524966

  18. Cortical pitch response components index stimulus onset/offset and dynamic features of pitch contours

    PubMed Central

    Krishnan, Ananthanarayan; Gandour, Jackson T.; Ananthakrishnan, Saradha; Vijayaraghavan, Venkatakrishnan

    2014-01-01

    Voice pitch is an important information-bearing component of language that is subject to experience dependent plasticity at both early cortical and subcortical stages of processing. We’ve already demonstrated that pitch onset component (Na) of the cortical pitch response (CPR) is sensitive to flat pitch and its salience. In regards to dynamic pitch, we do not yet know whether the multiple pitch-related transient components of the CPR reflect specific temporal attributes of such stimuli. Here we examine the sensitivity of the multiple transient components of CPR to changes in pitch acceleration associated with the Mandarin high rising lexical tone. CPR responses from Chinese listeners were elicited by three citation forms varying in pitch acceleration and duration. Results showed that the pitch onset component (Na) was invariant to changes in acceleration. In contrast, Na-Pb and Pb-Nb showed a systematic increase in the interpeak latency and decrease in amplitude with increase in pitch acceleration that followed the time course of pitch change across the three stimuli. A strong correlation with pitch acceleration was observed for these two components only – a putative index of pitch-relevant neural activity associated with the more rapidly-changing portions of the pitch contour. Pc-Nc marks unambiguously the stimulus offset. We therefore propose that in the early stages of cortical sensory processing, a series of neural markers flag different temporal attributes of a dynamic pitch contour: onset of temporal regularity (Na); changes in temporal regularity between onset and offset (Na-Pb, Pb-Nb); and offset of temporal regularity (Pc-Nc). At the temporal electrode sites, the stimulus with the most gradual change in pitch acceleration evoked a rightward asymmetry. Yet within the left hemisphere, stimuli with more gradual change were indistinguishable. These findings highlight the emergence of early hemispheric preferences and their functional roles as related to

  19. Effective Stimulus Parameters for Directed Locomotion in Madagascar Hissing Cockroach Biobot

    PubMed Central

    Erickson, Jonathan C.; Shingiro, Aristide; Bowen, Thomas

    2015-01-01

    Swarms of insects instrumented with wireless electronic backpacks have previously been proposed for potential use in search and rescue operations. Before deploying such biobot swarms, an effective long-term neural-electric stimulus interface must be established, and the locomotion response to various stimuli quantified. To this end, we studied a variety of pulse types (mono- vs. bipolar; voltage- vs. current-controlled) and shapes (amplitude, frequency, duration) to parameters that are most effective for evoking locomotion along a desired path in the Madagascar hissing cockroach (G. portentosa) in response to antennal and cercal stimulation. We identified bipolar, 2 V, 50 Hz, 0.5 s voltage controlled pulses as being optimal for evoking forward motion and turns in the expected contraversive direction without habituation in ≈50% of test subjects, a substantial increase over ≈10% success rates previously reported. Larger amplitudes for voltage (1–4 V) and current (50–150 μA) pulses generally evoked larger forward walking (15.6–25.6 cm; 3.9–5.6 cm/s) but smaller concomitant turning responses (149 to 80.0 deg; 62.8 to 41.2 deg/s). Thus, the radius of curvature of the initial turn-then-run locomotor response (≈10–25 cm) could be controlled in a graded manner by varying the stimulus amplitude. These findings could be used to help optimize stimulus protocols for swarms of cockroach biobots navigating unknown terrain. PMID:26308337

  20. Effective Stimulus Parameters for Directed Locomotion in Madagascar Hissing Cockroach Biobot.

    PubMed

    Erickson, Jonathan C; Herrera, María; Bustamante, Mauricio; Shingiro, Aristide; Bowen, Thomas

    2015-01-01

    Swarms of insects instrumented with wireless electronic backpacks have previously been proposed for potential use in search and rescue operations. Before deploying such biobot swarms, an effective long-term neural-electric stimulus interface must be established, and the locomotion response to various stimuli quantified. To this end, we studied a variety of pulse types (mono- vs. bipolar; voltage- vs. current-controlled) and shapes (amplitude, frequency, duration) to parameters that are most effective for evoking locomotion along a desired path in the Madagascar hissing cockroach (G. portentosa) in response to antennal and cercal stimulation. We identified bipolar, 2 V, 50 Hz, 0.5 s voltage controlled pulses as being optimal for evoking forward motion and turns in the expected contraversive direction without habituation in ≈50% of test subjects, a substantial increase over ≈10% success rates previously reported. Larger amplitudes for voltage (1-4 V) and current (50-150 μA) pulses generally evoked larger forward walking (15.6-25.6 cm; 3.9-5.6 cm/s) but smaller concomitant turning responses (149 to 80.0 deg; 62.8 to 41.2 deg/s). Thus, the radius of curvature of the initial turn-then-run locomotor response (≈10-25 cm) could be controlled in a graded manner by varying the stimulus amplitude. These findings could be used to help optimize stimulus protocols for swarms of cockroach biobots navigating unknown terrain.

  1. The effects of compound stimulus extinction and inhibition of noradrenaline reuptake on the renewal of alcohol seeking

    PubMed Central

    Furlong, T M; Pan, M J; Corbit, L H

    2015-01-01

    Alcohol-related stimuli can trigger relapse of alcohol-seeking behaviors even after extended periods of abstinence. Extinction of such stimuli can reduce their impact on relapse; however, the expression of extinction can be disrupted when testing occurs outside the context where extinction learning took place, an effect termed renewal. Behavioral and pharmacological methods have recently been shown to augment extinction learning; yet, it is not known whether the improved expression of extinction following these treatments remains context-dependent. Here we examined whether two methods, compound–stimulus extinction and treatment with the noradrenaline reuptake inhibitor atomoxetine, would reduce the vulnerability of extinction to a change in context. Following alcohol self-administration, responding was extinguished in a distinct context. After initial extinction, further extinction was given to a target stimulus presented in compound with another alcohol-predictive stimulus intended to augment prediction error (Experiment 1) or after a systemic injection of atomoxetine (1.0 mg kg−1; Experiment 2). A stimulus extinguished as part of a compound elicited less responding than a stimulus receiving equal extinction alone regardless of whether animals were tested in the training or extinction context; however, reliable renewal was not observed in this paradigm. Importantly, atomoxetine enhanced extinction relative to controls even in the presence of a reliable renewal effect. Thus, extinction of alcohol-seeking behavior can be improved by extinguishing multiple alcohol-predictive stimuli or enhancing noradrenaline neurotransmission during extinction training. Importantly, both methods improve extinction even when the context is changed between extinction training and test, and thus could be utilized to enhance the outcome of extinction-based treatments for alcohol-use disorders. PMID:26327688

  2. The effects of compound stimulus extinction and inhibition of noradrenaline reuptake on the renewal of alcohol seeking.

    PubMed

    Furlong, T M; Pan, M J; Corbit, L H

    2015-09-01

    Alcohol-related stimuli can trigger relapse of alcohol-seeking behaviors even after extended periods of abstinence. Extinction of such stimuli can reduce their impact on relapse; however, the expression of extinction can be disrupted when testing occurs outside the context where extinction learning took place, an effect termed renewal. Behavioral and pharmacological methods have recently been shown to augment extinction learning; yet, it is not known whether the improved expression of extinction following these treatments remains context-dependent. Here we examined whether two methods, compound-stimulus extinction and treatment with the noradrenaline reuptake inhibitor atomoxetine, would reduce the vulnerability of extinction to a change in context. Following alcohol self-administration, responding was extinguished in a distinct context. After initial extinction, further extinction was given to a target stimulus presented in compound with another alcohol-predictive stimulus intended to augment prediction error (Experiment 1) or after a systemic injection of atomoxetine (1.0 mg kg(-1); Experiment 2). A stimulus extinguished as part of a compound elicited less responding than a stimulus receiving equal extinction alone regardless of whether animals were tested in the training or extinction context; however, reliable renewal was not observed in this paradigm. Importantly, atomoxetine enhanced extinction relative to controls even in the presence of a reliable renewal effect. Thus, extinction of alcohol-seeking behavior can be improved by extinguishing multiple alcohol-predictive stimuli or enhancing noradrenaline neurotransmission during extinction training. Importantly, both methods improve extinction even when the context is changed between extinction training and test, and thus could be utilized to enhance the outcome of extinction-based treatments for alcohol-use disorders.

  3. Stimulus Variability and Perceptual Learning of Nonnative Vowel Categories

    ERIC Educational Resources Information Center

    Brosseau-Lapre, Francoise; Rvachew, Susan; Clayards, Meghan; Dickson, Daniel

    2013-01-01

    English-speakers' learning of a French vowel contrast (/schwa/-/slashed o/) was examined under six different stimulus conditions in which contrastive and noncontrastive stimulus dimensions were varied orthogonally to each other. The distribution of contrastive cues was varied across training conditions to create single prototype, variable far…

  4. Motormouth: Mere Exposure Depends on Stimulus-Specific Motor Simulations

    ERIC Educational Resources Information Center

    Topolinski, Sascha; Strack, Fritz

    2009-01-01

    The authors apply an embodied account to mere exposure, arguing that through the repeated exposure of a particular stimulus, motor responses specifically associated to that stimulus are repeatedly simulated, thus trained, and become increasingly fluent. This increased fluency drives preferences for repeated stimuli. This hypothesis was tested by…

  5. Mechanics of Coriolis stimulus and inducing factors of motion sickness.

    PubMed

    Isu, N; Shimizu, T; Sugata, K

    2001-12-01

    To specify inducing factors of motion sickness comprised in Coriolis stimulus, or cross-coupled rotation, the sensation of rotation derived from the semicircular canal system during and after Coriolis stimulus under a variety of stimulus conditions, was estimated by an approach from mechanics with giving minimal hypotheses and simplifications on the semicircular canal system and the sensory nervous system. By solving an equation of motion of the endolymph during Coriolis stimulus, rotating angle of the endolymph was obtained, and the sensation of rotation derived from each semicircular canal was estimated. Then the sensation derived from the whole semicircular canal system was particularly considered in two cases of a single Coriolis stimulus and cyclic Coriolis stimuli. The magnitude and the direction of sensation of rotation were shown to depend on an angular velocity of body rotation and a rotating angle of head movement (amplitude of head oscillation when cyclic Coriolis stimuli) irrespective of initial angle (center angle) of the head relative to the vertical axis. The present mechanical analysis of Coriolis stimulus led a suggestion that the severity of nausea evoked by Coriolis stimulus is proportional to the effective value of the sensation of rotation caused by the Coriolis stimulus.

  6. Visual Decisions in the Presence of Measurement and Stimulus Correlations

    PubMed Central

    Bhardwaj, Manisha; Carroll, Samuel; Ma, Wei Ji; Josić, Krešimir

    2015-01-01

    Humans and other animals base their decisions on noisy sensory input. Much work has been devoted to understanding the computations that underlie such decisions. The problem has been studied in a variety of tasks and with stimuli of differing complexity. However, how the statistical structure of stimuli, along with perceptual measurement noise, affects perceptual judgments is not well understood. Here we examine how correlations between the components of a stimulus—stimulus correlations—together with correlations in sensory noise, affect decision making. As an example, we consider the task of detecting the presence of a single or multiple targets among distractors. We assume that both the distractors and the observer’s measurements of the stimuli are correlated. The computations of an optimal observer in this task are nontrivial yet can be analyzed and understood intuitively. We find that when distractors are strongly correlated, measurement correlations can have a strong impact on performance. When distractor correlations are weak, measurement correlations have little impact unless the number of stimuli is large. Correlations in neural responses to structured stimuli can therefore have a strong impact on perceptual judgments. PMID:26378875

  7. A transformation of respondently conditioned stimulus function in accordance with arbitrarily applicable relations.

    PubMed Central

    Roche, B; Barnes, D

    1997-01-01

    Adult male subjects saw a sexual film clip paired with a nonsense syllable (C1). Similarly, an emotionally neutral film clip was paired with a second nonsense syllable (C3). Responses to the nonsense syllables were recorded as skin resistance responses. Subjects were also trained in a series of related conditional discriminations, using the C1 and C3 stimuli, from which the following equivalence relations were predicted; A1-B1-C1, A2-B2-C2, and A3-B3-C3. Some subjects were given matching-to-sample (equivalence) tests after the conditional discrimination training (Experiment 1), whereas others were not (Experiment 2). Subjects were tested for a transformation of eliciting functions by presenting the A1 and A3 stimuli, which were related through equivalence to C1 and C3, respectively. Five of the 6 subjects who showed significantly greater conditioned responses to C1 than to C3, also showed significantly greater skin resistance responses to A1 than to A3. Two additional subjects demonstrated a transformation of an eliciting stimulus function in accordance with five-member equivalence relations (Experiment 3), and another 5 subjects demonstrated similar effects in accordance with the relations of sameness and opposition (Experiment 4). PMID:9163935

  8. Reward feedback stimuli elicit high-beta EEG oscillations in human dorsolateral prefrontal cortex

    PubMed Central

    Hosseini, Azadeh Haji; Holroyd, Clay B.

    2015-01-01

    Reward-related feedback stimuli have been observed to elicit a burst of power in the beta frequency range over frontal areas of the human scalp. Recent discussions have suggested possible neural sources for this activity but there is a paucity of empirical evidence on the question. Here we recorded EEG from participants while they navigated a virtual T-maze to find monetary rewards. Consistent with previous studies, we found that the reward feedback stimuli elicited an increase in beta power (20–30 Hz) over a right-frontal area of the scalp. Source analysis indicated that this signal was produced in the right dorsolateral prefrontal cortex (DLPFC). These findings align with previous observations of reward-related beta oscillations in the DLPFC in non-human primates. We speculate that increased power in the beta frequency range following reward receipt reflects the activation of task-related neural assemblies that encode the stimulus-response mapping in working memory. PMID:26278335

  9. Effect of spontaneous activity on stimulus detection in a simple neuronal model.

    PubMed

    Levakova, Marie

    2016-06-01

    It is studied what level of a continuous-valued signal is optimally estimable on the basis of first-spike latency neuronal data. When a spontaneous neuronal activity is present, the first spike after the stimulus onset may be caused either by the stimulus itself, or it may be a result of the prevailing spontaneous activity. Under certain regularity conditions, Fisher information is the inverse of the variance of the best estimator. It can be considered as a function of the signal intensity and then indicates accuracy of the estimation for each signal level. The Fisher information is normalized with respect to the time needed to obtain an observation. The accuracy of signal level estimation is investigated in basic discharge patterns modelled by a Poisson and a renewal process and the impact of the complex interaction between spontaneous activity and a delay of the response is shown.

  10. Distinguishing Conjoint and Independent Neural Tuning for Stimulus Features With fMRI Adaptation

    PubMed Central

    Drucker, Daniel M.; Kerr, Wesley Thomas; Aguirre, Geoffrey Karl

    2009-01-01

    A central focus of cognitive neuroscience is identification of the neural codes that represent stimulus dimensions. One common theme is the study of whether dimensions, such as color and shape, are encoded independently by separate pools of neurons or are represented by neurons conjointly tuned for both properties. We describe an application of functional magnetic resonance imaging (fMRI) adaptation to distinguish between independent and conjoint neural representations of dimensions by examining the neural signal evoked by changes in one versus two stimulus dimensions and considering the metric of two-dimension additivity. We describe how a continuous carry-over paradigm may be used to efficiently estimate this metric. The assumptions of the method are examined as are optimizations. Finally, we demonstrate that the method produces the expected result for fMRI data collected from ventral occipitotemporal cortex while subjects viewed sets of shapes predicted to be represented by conjoint or independent neural tuning. PMID:19357342

  11. Effect of spontaneous activity on stimulus detection in a simple neuronal model.

    PubMed

    Levakova, Marie

    2016-06-01

    It is studied what level of a continuous-valued signal is optimally estimable on the basis of first-spike latency neuronal data. When a spontaneous neuronal activity is present, the first spike after the stimulus onset may be caused either by the stimulus itself, or it may be a result of the prevailing spontaneous activity. Under certain regularity conditions, Fisher information is the inverse of the variance of the best estimator. It can be considered as a function of the signal intensity and then indicates accuracy of the estimation for each signal level. The Fisher information is normalized with respect to the time needed to obtain an observation. The accuracy of signal level estimation is investigated in basic discharge patterns modelled by a Poisson and a renewal process and the impact of the complex interaction between spontaneous activity and a delay of the response is shown. PMID:27106186

  12. Stimulus control during conditional discrimination1

    PubMed Central

    Yarczower, Matthew

    1971-01-01

    Pigeons were used to assess stimulus control during the development of a conditional discrimination. The training consisted of three stages. In Stage 1, key pecks were reinforced in the presence of a white line tilted 40° to the right of vertical on a green background and non-reinforced when the same line appeared on a red background. In Stage 2, key pecks were reinforced when a white vertical line appeared on a red background and were non-reinforced in the presence of a 40° slanted line on a red background. In Stage 3, key pecks were reinforced in the presence of the green background regardless of the line tilt, but were differentially reinforced in the presence of the red background (as in Stage 2). Generalization tests were conducted after each stage of training and consisted of five white lines on backgrounds that were green, red, or dark. The effects of the differential reinforcement contingencies on control by line orientation were restricted to the condition in which the red light appeared and resulted in behavioral control that could be characterized as: if red, pay closer attention to line tilt than if not red. PMID:5142389

  13. Stimulus properties of fixed-interval responses.

    PubMed

    Buchman, I B; Zeiler, M D

    1975-11-01

    Responses in the first component of a chained schedule produced a change to the terminal component according to a fixed-interval schedule. The number of responses emitted in the fixed interval determined whether a variable-interval schedule of food presentation or extinction prevailed in the terminal component. In one condition, the variable-interval schedule was in effect only if the number of responses during the fixed interval was less than that specified; in another condition, the number of responses had to exceed that specified. The number of responses emitted in the fixed interval did not shift markedly in the direction required for food presentation. Instead, responding often tended to change in the opposite direction. Such an effect indicated that differential food presentation did not modify the reference behavior in accord with the requirement, but it was consistent with other data on fixed-interval schedule performance. Behavior in the terminal component, however, did reveal sensitivity to the relation between total responses emitted in the fixed interval and the availability of food. Response rate in the terminal component was a function of the proximity of the response number emitted in the fixed interval to that required for food presentation. Thus, response number served as a discriminative stimulus controlling subsequent performance.

  14. Transformation of stimulus correlations by the retina.

    PubMed

    Simmons, Kristina D; Prentice, Jason S; Tkačik, Gašper; Homann, Jan; Yee, Heather K; Palmer, Stephanie E; Nelson, Philip C; Balasubramanian, Vijay

    2013-01-01

    Redundancies and correlations in the responses of sensory neurons may seem to waste neural resources, but they can also carry cues about structured stimuli and may help the brain to correct for response errors. To investigate the effect of stimulus structure on redundancy in retina, we measured simultaneous responses from populations of retinal ganglion cells presented with natural and artificial stimuli that varied greatly in correlation structure; these stimuli and recordings are publicly available online. Responding to spatio-temporally structured stimuli such as natural movies, pairs of ganglion cells were modestly more correlated than in response to white noise checkerboards, but they were much less correlated than predicted by a non-adapting functional model of retinal response. Meanwhile, responding to stimuli with purely spatial correlations, pairs of ganglion cells showed increased correlations consistent with a static, non-adapting receptive field and nonlinearity. We found that in response to spatio-temporally correlated stimuli, ganglion cells had faster temporal kernels and tended to have stronger surrounds. These properties of individual cells, along with gain changes that opposed changes in effective contrast at the ganglion cell input, largely explained the pattern of pairwise correlations across stimuli where receptive field measurements were possible.

  15. Regulatory Fit Effects on Stimulus Identification

    PubMed Central

    Glass, Brian D.; Maddox, W. Todd; Markmana, Arthur B.

    2010-01-01

    This article examines the effects of a fit between a person's global regulatory focus and the local task reward structure on perceptual processing and judgment. On each trial, participants were presented with one of two briefly presented stimuli and were asked to identify it. Participants were placed in a promotion focus (a situationally induced sensitivity to gains) or a prevention focus (a situationally induced sensitivity to losses) and were asked to maximize gains or minimize losses. An asymmetric payoff ratio biased the overall reward toward one identification response over the other. Two experiments tested the role of regulatory fit when internal familiarity and perceptual sensitivity was low or high. When familiarity and sensitivity were low, participants in a regulatory fit (promotion focus with gains or a prevention focus with losses) showed greater perceptual sensitivity, but no response bias differences relative to participants in a regulatory mismatch. When familiarity and sensitivity were high, participants in a regulatory fit showed a response bias toward the high payoff stimulus, but no differences in perceptual sensitivity. Speculation on the neurobiological basis of this effect, as well as implications of this work for clinical disorders, such as depression, is offered. PMID:21264696

  16. Electric stimulus opens intercellular spaces in skin.

    PubMed

    Hama, Susumu; Kimura, Yuki; Mikami, Aya; Shiota, Kanako; Toyoda, Mao; Tamura, Atsushi; Nagasaki, Yukio; Kanamura, Kiyoshi; Kajimoto, Kazuaki; Kogure, Kentaro

    2014-01-24

    Iontophoresis is a technology for transdermal delivery of ionic small medicines by faint electricity. Since iontophoresis can noninvasively deliver charged molecules into the skin, this technology could be a useful administration method that may enhance patient comfort. Previously, we succeeded in the transdermal penetration of positively charged liposomes (diameters: 200-400 nm) encapsulating insulin by iontophoresis (Kajimoto, K., Yamamoto, M., Watanabe, M., Kigasawa, K., Kanamura, K., Harashima, H., and Kogure, K. (2011) Int. J. Pharm. 403, 57-65). However, the mechanism by which these liposomes penetrated the skin was difficult to define based on general knowledge of principles such as electro-repulsion and electro-osmosis. In the present study, we confirmed that rigid nanoparticles could penetrate into the epidermis by iontophoresis. We further found that levels of the gap junction protein connexin 43 protein significantly decreased after faint electric stimulus (ES) treatment, although occludin, CLD-4, and ZO-1 levels were unchanged. Moreover, connexin 43 phosphorylation and filamentous actin depolymerization in vivo and in vitro were observed when permeation of charged liposomes through intercellular spaces was induced by ES. Ca(2+) inflow into cells was promoted by ES with charged liposomes, while a protein kinase C inhibitor prevented ES-induced permeation of macromolecules. Consequently, we demonstrate that ES treatment with charged liposomes induced dissociation of intercellular junctions via cell signaling pathways. These findings suggest that ES could be used to regulate skin physiology.

  17. Evaluation of an Enhanced Stimulus-Stimulus Pairing Procedure to Increase Early Vocalizations of Children with Autism

    ERIC Educational Resources Information Center

    Esch, Barbara E.; Carr, James E.; Grow, Laura L.

    2009-01-01

    Evidence to support stimulus-stimulus pairing (SSP) in speech acquisition is less than robust, calling into question the ability of SSP to reliably establish automatically reinforcing properties of speech and limiting the procedure's clinical utility for increasing vocalizations. We evaluated the effects of a modified SSP procedure on…

  18. The role of the 5-HT2A and 5-HT2C receptors in the stimulus effects of hallucinogenic drugs. I: Antagonist correlation analysis.

    PubMed

    Fiorella, D; Rabin, R A; Winter, J C

    1995-10-01

    Investigations conducted over the past 3 decades have demonstrated that serotonergic receptors, specifically the 5-HT2A and 5-HT2C subtypes, play an important role in the behavioral effects of hallucinogenic compounds. The present study was designed to determine the respective significance of these two receptors in the stimulus effects of LSD and (-)DOM in the rat. Specifically, the interactions of a series of serotonergic antagonists (risperidone, pirenpirone, metergoline, ketanserin, loxapine, LY53857, pizotyline, spiperone, cyprohepatadine, mesulergine, promethazine, and thioridazine) with the LSD stimulus and the (-)DOM stimulus in LSD-trained subjects was defined. From these data, IC50 values were determined for the inhibition of the LSD-appropriate responding elicited by either 0.1 mg/kg LSD (15-min pretreatment time) or 0.4 mg/kg (-)DOM (75-min pretreatment). In addition, the affinities of these antagonists for 5-HT2A and 5-HT2C receptors were determined in radioligand competition studies, 5-HT2A affinity correlated significantly with IC50 values for the blockade of the LSD (r = +0.75, P < 0.05) and (-)DOM (r = +0.95, P < 0.001) stimuli in the LSD trained subjects. 5-HT2C affinity did not correlate significantly with either series of IC50 values. These data indicate that (1) the stimulus effects of LSD, and (2) the substitution of (-)DOM for the LSD stimulus are mediated by agonist activity at 5-HT2A receptors.

  19. Patterns on serpentine shapes elicit visual attention in marmosets (Callithrix jacchus).

    PubMed

    Wombolt, Jessica R; Caine, Nancy G

    2016-09-01

    Given the prevalence of threatening snakes in the evolutionary history, and modern-day environments of human and nonhuman primates, sensory, and perceptual abilities that allow for quick detection of, and appropriate response to snakes are likely to have evolved. Many studies have demonstrated that primates recognize snakes faster than other stimuli, and it is suggested that the unique serpentine shape is responsible for its quick detection. However, there are many nonthreatening serpentine shapes in the environment (e.g., vines) that are not threatening; therefore, other cues must be used to distinguish threatening from benign serpentine objects. In two experiments, we systematically evaluated how common marmosets (Callithrix jacchus) visually attend to specific snake-like features. In the first experiment, we examined if skin pattern is a cue that elicits increased visual inspection of serpentine shapes by measuring the amount of time the marmosets looked into a blind before, during, and after presentation of clay models with and without patterns. The marmosets spent the most time looking at the objects, both serpentine and triangle, that were etched with scales, suggesting that something may be uniquely salient about scales in evoking attention. In contrast, they showed relatively little interest in the unpatterned serpentine and control (a triangle) stimuli. In experiment 2, we replicated and extended the results of experiment 1 by adding additional stimulus conditions. We found that patterns on a serpentine shape generated more inspection than those same patterns on a triangle shape. We were unable to confirm that a scaled pattern is unique in its ability to elicit visual interest; the scaled models elicited similar looking times as line and star patterns. Our data provide a foundation for future research to examine how snakes are detected and identified by primates. Am. J. Primatol. 78:928-936, 2016. © 2016 Wiley Periodicals, Inc. PMID:27225979

  20. Event-related potentials elicited by pre-attentive emotional changes in temporal context.

    PubMed

    Fujimura, Tomomi; Okanoya, Kazuo

    2013-01-01

    The ability to detect emotional change in the environment is essential for adaptive behavior. The current study investigated whether event-related potentials (ERPs) can reflect emotional change in a visual sequence. To assess pre-attentive processing, we examined visual mismatch negativity (vMMN): the negative potentials elicited by a deviant (infrequent) stimulus embedded in a sequence of standard (frequent) stimuli. Participants in two experiments pre-attentively viewed visual sequences of Japanese kanji with different emotional connotations while ERPs were recorded. The visual sequence in Experiment 1 consisted of neutral standards and two types of emotional deviants with a strong and weak intensity. Although the results indicated that strongly emotional deviants elicited more occipital negativity than neutral standards, it was unclear whether these negativities were derived from emotional deviation in the sequence or from the emotional significance of the deviants themselves. In Experiment 2, the two identical emotional deviants were presented against different emotional standards. One type of deviants was emotionally incongruent with the standard and the other type of deviants was emotionally congruent with the standard. The results indicated that occipital negativities elicited by deviants resulted from perceptual changes in a visual sequence at a latency of 100-200 ms and from emotional changes at latencies of 200-260 ms. Contrary to the results of the ERP experiment, reaction times to deviants showed no effect of emotional context; negative stimuli were consistently detected more rapidly than were positive stimuli. Taken together, the results suggest that brain signals can reflect emotional change in a temporal context. PMID:23671693

  1. Patterns on serpentine shapes elicit visual attention in marmosets (Callithrix jacchus).

    PubMed

    Wombolt, Jessica R; Caine, Nancy G

    2016-09-01

    Given the prevalence of threatening snakes in the evolutionary history, and modern-day environments of human and nonhuman primates, sensory, and perceptual abilities that allow for quick detection of, and appropriate response to snakes are likely to have evolved. Many studies have demonstrated that primates recognize snakes faster than other stimuli, and it is suggested that the unique serpentine shape is responsible for its quick detection. However, there are many nonthreatening serpentine shapes in the environment (e.g., vines) that are not threatening; therefore, other cues must be used to distinguish threatening from benign serpentine objects. In two experiments, we systematically evaluated how common marmosets (Callithrix jacchus) visually attend to specific snake-like features. In the first experiment, we examined if skin pattern is a cue that elicits increased visual inspection of serpentine shapes by measuring the amount of time the marmosets looked into a blind before, during, and after presentation of clay models with and without patterns. The marmosets spent the most time looking at the objects, both serpentine and triangle, that were etched with scales, suggesting that something may be uniquely salient about scales in evoking attention. In contrast, they showed relatively little interest in the unpatterned serpentine and control (a triangle) stimuli. In experiment 2, we replicated and extended the results of experiment 1 by adding additional stimulus conditions. We found that patterns on a serpentine shape generated more inspection than those same patterns on a triangle shape. We were unable to confirm that a scaled pattern is unique in its ability to elicit visual interest; the scaled models elicited similar looking times as line and star patterns. Our data provide a foundation for future research to examine how snakes are detected and identified by primates. Am. J. Primatol. 78:928-936, 2016. © 2016 Wiley Periodicals, Inc.

  2. Expert elicitation of population-level effects of disturbance

    USGS Publications Warehouse

    Fleishman, Erica; Burgman, Mark; Runge, Michael C.; Schick, Robert S; Krauss, Scott; Popper, Arthur N.; Hawkins, Anthony

    2016-01-01

    Expert elicitation is a rigorous method for synthesizing expert knowledge to inform decision making and is reliable and practical when field data are limited. We evaluated the feasibility of applying expert elicitation to estimate population-level effects of disturbance on marine mammals. Diverse experts estimated parameters related to mortality and sublethal injury of North Atlantic right whales (Eubalaena glacialis). We are now eliciting expert knowledge on the movement of right whales among geographic regions to parameterize a spatial model of health. Expert elicitation complements methods such as simulation models or extrapolations from other species, sometimes with greater accuracy and less uncertainty.

  3. Expert Elicitation of Population-Level Effects of Disturbance.

    PubMed

    Fleishman, Erica; Burgman, Mark; Runge, Michael C; Schick, Robert S; Kraus, Scott

    2016-01-01

    Expert elicitation is a rigorous method for synthesizing expert knowledge to inform decision making and is reliable and practical when field data are limited. We evaluated the feasibility of applying expert elicitation to estimate population-level effects of disturbance on marine mammals. Diverse experts estimated parameters related to mortality and sublethal injury of North Atlantic right whales (Eubalaena glacialis). We are now eliciting expert knowledge on the movement of right whales among geographic regions to parameterize a spatial model of health. Expert elicitation complements methods such as simulation models or extrapolations from other species, sometimes with greater accuracy and less uncertainty. PMID:26610972

  4. Finding the missing-stimulus mismatch negativity (MMN) in early psychosis: altered MMN to violations of an auditory gestalt.

    PubMed

    Rudolph, Erica D; Ells, Emma M L; Campbell, Debra J; Abriel, Shelagh C; Tibbo, Philip G; Salisbury, Dean F; Fisher, Derek J

    2015-08-01

    The mismatch negativity (MMN) is an EEG-derived event-related potential (ERP) elicited by any violation of a predicted auditory 'rule', regardless of whether one is attending to the stimuli, and is thought to reflect updating of the stimulus context. Chronic schizophrenia patients exhibit robust MMN deficits, while MMN reduction in first-episode and early phase psychosis is significantly less consistent. Traditional two-tone "oddball" MMN measures of sensory information processing may be considered too simple for use in early phase psychosis in which pathology has not progressed fully, and a paradigm that probes higher order processes may be more appropriate for elucidating auditory change detection deficits. This study investigated whether MMN deficits could be detected in early phase psychosis (EP) patients using an abstract 'missing stimulus' pattern paradigm (Salisbury, 2012). The stimuli were 400 groups of six tones (1000Hz, 50ms duration, 330ms stimulus onset asynchrony), which was presented with an inter-trial interval of 750ms. Occasionally a group contained a deviant, meaning that it was missing either the 4th or 6th tone (50 trials each). EEG recordings of 13 EP patients (≤5year duration of illness) and 15 healthy controls (HC) were collected. Patients and controls did not significantly differ on age or years of education. Analyses of MMN amplitudes elicited by missing stimuli revealed amplitude reductions in EP patients, suggesting that these deficits are present very early in the progression of the illness. While there were no correlations between MMN measures and measures such as duration of illness, medication dosage or age, MMN amplitude reductions were correlated with positive symptomatology (i.e. auditory hallucinations). These findings suggest that MMNs elicited by the 'missing stimulus' paradigm are impaired in psychosis patients early in the progression of illness and that previously reported MMN-indexed deficits related to auditory

  5. Finding the missing-stimulus mismatch negativity (MMN) in early psychosis: altered MMN to violations of an auditory gestalt.

    PubMed

    Rudolph, Erica D; Ells, Emma M L; Campbell, Debra J; Abriel, Shelagh C; Tibbo, Philip G; Salisbury, Dean F; Fisher, Derek J

    2015-08-01

    The mismatch negativity (MMN) is an EEG-derived event-related potential (ERP) elicited by any violation of a predicted auditory 'rule', regardless of whether one is attending to the stimuli, and is thought to reflect updating of the stimulus context. Chronic schizophrenia patients exhibit robust MMN deficits, while MMN reduction in first-episode and early phase psychosis is significantly less consistent. Traditional two-tone "oddball" MMN measures of sensory information processing may be considered too simple for use in early phase psychosis in which pathology has not progressed fully, and a paradigm that probes higher order processes may be more appropriate for elucidating auditory change detection deficits. This study investigated whether MMN deficits could be detected in early phase psychosis (EP) patients using an abstract 'missing stimulus' pattern paradigm (Salisbury, 2012). The stimuli were 400 groups of six tones (1000Hz, 50ms duration, 330ms stimulus onset asynchrony), which was presented with an inter-trial interval of 750ms. Occasionally a group contained a deviant, meaning that it was missing either the 4th or 6th tone (50 trials each). EEG recordings of 13 EP patients (≤5year duration of illness) and 15 healthy controls (HC) were collected. Patients and controls did not significantly differ on age or years of education. Analyses of MMN amplitudes elicited by missing stimuli revealed amplitude reductions in EP patients, suggesting that these deficits are present very early in the progression of the illness. While there were no correlations between MMN measures and measures such as duration of illness, medication dosage or age, MMN amplitude reductions were correlated with positive symptomatology (i.e. auditory hallucinations). These findings suggest that MMNs elicited by the 'missing stimulus' paradigm are impaired in psychosis patients early in the progression of illness and that previously reported MMN-indexed deficits related to auditory

  6. Enhanced spatial stimulus-response mapping near the hands: the Simon effect is modulated by hand-stimulus proximity.

    PubMed

    Wang, Xiaotao; Du, Feng; He, Xiaosong; Zhang, Kan

    2014-12-01

    Emerging evidence has revealed that visual processing of objects near the hands is altered. The present study shows that the visuomotor Simon effect when the hands are proximal to stimuli is greater than that observed when the hands are far from stimuli, thereby indicating stronger spatial stimulus-response mapping near the hands. The visuomotor Simon effect is robustly enhanced near the hands even when hand visibility and stimulus-response axis-similarity are controlled. However, the semantic Simon effect with location words is not modulated by hand-stimulus proximity. Thus, consistent with the dimensional overlap model and the known features of the bimodal visuotactile neurons, hand-stimulus proximity enhances spatial stimulus-response mapping but has no effect on semantic processing of location words.

  7. Inseparability of Go and Stop in Inhibitory Control: Go Stimulus Discriminability Affects Stopping Behavior.

    PubMed

    Ma, Ning; Yu, Angela J

    2016-01-01

    Inhibitory control, the ability to stop or modify preplanned actions under changing task conditions, is an important component of cognitive functions. Two lines of models of inhibitory control have previously been proposed for human response in the classical stop-signal task, in which subjects must inhibit a default go response upon presentation of an infrequent stop signal: (1) the race model, which posits two independent go and stop processes that race to determine the behavioral outcome, go or stop; and (2) an optimal decision-making model, which posits that observers decides whether and when to go based on continually (Bayesian) updated information about both the go and stop stimuli. In this work, we probe the relationship between go and stop processing by explicitly manipulating the discrimination difficulty of the go stimulus. While the race model assumes the go and stop processes are independent, and therefore go stimulus discriminability should not affect the stop stimulus processing, we simulate the optimal model to show that it predicts harder go discrimination should result in longer go reaction time (RT), lower stop error rate, as well as faster stop-signal RT. We then present novel behavioral data that validate these model predictions. The results thus favor a fundamentally inseparable account of go and stop processing, in a manner consistent with the optimal model, and contradicting the independence assumption of the race model. More broadly, our findings contribute to the growing evidence that the computations underlying inhibitory control are systematically modulated by cognitive influences in a Bayes-optimal manner, thus opening new avenues for interpreting neural responses underlying inhibitory control.

  8. Inseparability of Go and Stop in Inhibitory Control: Go Stimulus Discriminability Affects Stopping Behavior.

    PubMed

    Ma, Ning; Yu, Angela J

    2016-01-01

    Inhibitory control, the ability to stop or modify preplanned actions under changing task conditions, is an important component of cognitive functions. Two lines of models of inhibitory control have previously been proposed for human response in the classical stop-signal task, in which subjects must inhibit a default go response upon presentation of an infrequent stop signal: (1) the race model, which posits two independent go and stop processes that race to determine the behavioral outcome, go or stop; and (2) an optimal decision-making model, which posits that observers decides whether and when to go based on continually (Bayesian) updated information about both the go and stop stimuli. In this work, we probe the relationship between go and stop processing by explicitly manipulating the discrimination difficulty of the go stimulus. While the race model assumes the go and stop processes are independent, and therefore go stimulus discriminability should not affect the stop stimulus processing, we simulate the optimal model to show that it predicts harder go discrimination should result in longer go reaction time (RT), lower stop error rate, as well as faster stop-signal RT. We then present novel behavioral data that validate these model predictions. The results thus favor a fundamentally inseparable account of go and stop processing, in a manner consistent with the optimal model, and contradicting the independence assumption of the race model. More broadly, our findings contribute to the growing evidence that the computations underlying inhibitory control are systematically modulated by cognitive influences in a Bayes-optimal manner, thus opening new avenues for interpreting neural responses underlying inhibitory control. PMID:27047324

  9. Basic emotions elicited by odors and pictures.

    PubMed

    Croy, Ilona; Olgun, Selda; Joraschky, Peter

    2011-12-01

    The sense of olfaction is often reported to have a special relationship with emotional processing. Memories triggered by olfactory cues often have a very emotional load. On the other hand, basic negative or positive emotional states should be sufficient to cover the most significant functions of the olfactory system including ingestion, hazard avoidance, and social communication. Thus, we investigated whether different basic emotions can be evoked in healthy people through the sense of olfaction. We asked 119 participants which odor evokes one of the six basic emotions (happiness, disgust, anger, anxiety, sadness, and surprise); another 97 participants were asked about pictures evoking those emotions. The results showed that almost every participant could name an olfactory elicitor for happiness or disgust. Olfactory elicitors of anxiety were reported less frequently, but they were still reported by three-quarters of the participants. However, for sadness and anger only about half of the participants reported an olfactory elicitor, whereas significantly more named a visual cue. Olfactory emotion elicitors were mainly related to the classes of culture, plants, and food, and visual emotion elicitors were largely related to humans. This data supports the hypothesis that in the vast majority of people, few differentiated emotions can be elicited through the olfactory channel. These emotions are happiness, disgust, and anxiety.

  10. Acting green elicits a literal warm glow

    NASA Astrophysics Data System (ADS)

    Taufik, Danny; Bolderdijk, Jan Willem; Steg, Linda

    2015-01-01

    Environmental policies are often based on the assumption that people only act environmentally friendly if some extrinsic reward is implicated, usually money. We argue that people might also be motivated by intrinsic rewards: doing the right thing (such as acting environmentally friendly) elicits psychological rewards in the form of positive feelings, a phenomenon known as warm glow. Given the fact that people's psychological state may affect their thermal state, we expected that this warm glow could express itself quite literally: people who act environmentally friendly may perceive the temperature to be higher. In two studies, we found that people who learned they acted environmentally friendly perceived a higher temperature than people who learned they acted environmentally unfriendly. The underlying psychological mechanism pertains to the self-concept: learning you acted environmentally friendly signals to yourself that you are a good person. Together, our studies show that acting environmentally friendly can be psychologically rewarding, suggesting that appealing to intrinsic rewards can be an alternative way to encourage pro-environmental actions.

  11. Stimulus-response coupling in platelets

    SciTech Connect

    Huang, E.M.

    1986-01-01

    To understand the mechanism of stimulus-response coupling in platelets, the potentiating effect of succinate and lithium on platelet activation was examined. The action of succinate was immediate; preincubation with succinate did not lead to desensitization. Succinate was comparable to ADP in lowering cAMP levels previously elevated by PGl/sub 2/. Since inhibition of cAMP is not a prerequisite for platelet activation, the mechanism of potentiation of succinate remains undefined. Lithium has also been shown to inhibit adenylate cyclase in PGl/sub 2/-pretreated platelets. Lithium, however, can also inhibit inositol phosphate (InsP) phosphatase and lead to an accumulation of InsP. In human platelets, lithium also enhanced the thrombin-induced accumulation of (/sup 3/H)inositol-labelled inositol trisphosphate (InsP/sub 3/), and inositol bisphosphate (InsP/sub 2/). One hour after thrombin addition, all 3 inositol phosphates returned to near basal levels. In the presence of lithium, while labelled InsP/sub 2/ and InsP/sub 3/ returned to their respective basal levels, the InsP level remained elevated, consistent with the known inhibitory effect of lithium on InsP phosphatase. In thrombin-stimulated platelets prelabeled with (/sup 32/P)phosphate, lithium led to a decrease in labelled phosphatidylinositol 4-phosphate (PtdIns4P) as well as an enhanced production of labelled lysophosphatidylinositol, suggesting multiple effects of lithium on platelet phosphoinositide metabolism. These observed effects, however, occurred too slowly to be the mechanism by which lithium potentiated agonist-induced platelet activation. To study the agonist-receptor interaction, the effect of the specific, high affinity thrombin inhibitor, hirudin, on thrombin-induced accumulation of (/sup 3/H)inositol-labelled inositol phosphates was studied.

  12. Gender and Stimulus Control of Smoking Behavior

    PubMed Central

    Frandsen, Mai; Dunbar, Michael S.; Shiffman, Saul

    2015-01-01

    Introduction: Gender differences in smoking behavior have been proposed to account for poorer outcomes among women attempting to quit. Specifically, it has been suggested that women’s smoking behavior is less motivated by nicotine-seeking and more driven by environmental cues. To date, however, few real-world studies have examined the hypothesis that women’s smoking is under greater stimulus control. Methods: One hundred and ninety four daily smokers (men = 107; women = 87) completed 3 weeks of ecological momentary assessment (EMA) monitoring that provided data on real-world smoking behavior by reporting on situational contexts shown by previous research to influence smoking behavior (including social setting, cigarette availability, alcohol consumption, and mood). Results: Analyses of particular cues found few gender differences; however, men’s smoking increased to a greater extent compared with women’s when they were with others who were smoking. Idiographic analyses that allow individual subjects to have different directions of linkage to situational cues also were conducted to assess how predictable subjects’ smoking was from a range of contextual characteristics. Compared with women, men’s smoking was significantly more closely tied to food/alcohol consumption and tended to be more closely tied to social context. No other gender differences were found. Conclusions: EMA analyses suggest that men and women are similarly influenced by cues, including mood. Where there were gender differences, it was men rather than women whose smoking behavior was more influenced by cues. The data contradict the hypothesis that women’s smoking is more influenced by cues. PMID:25762752

  13. Ligand-directed trafficking of receptor stimulus.

    PubMed

    Chilmonczyk, Zdzisław; Bojarski, Andrzej J; Sylte, Ingebrigt

    2014-12-01

    GPCRs are seven transmembrane-spanning receptors that convey specific extracellular stimuli to intracellular signalling. They represent the largest family of cell surface proteins that are therapeutically targeted. According to the traditional two-state model of receptor theory, GPCRs were considered as operating in equilibrium between two functional conformations, an active (R*) and inactive (R) state. Thus, it was assumed that a GPCR can exist either in an "off" or "on" conformation causing either no activation or equal activation of all its signalling pathways. Over the past several years it has become evident that this model is too simple and that GPCR signalling is far more complex. Different studies have presented a multistate model of receptor activation in which ligand-specific receptor conformations are able to differentiate between distinct signalling partners. Recent data show that beside G proteins numerous other proteins, such as β-arrestins and kinases, may interact with GPCRs and activate intracellular signalling pathways. GPCR activation may therefore involve receptor desensitization, coupling to multiple G proteins, Gα or Gβγ signalling, and pathway activation that is independent of G proteins. This latter effect leads to agonist "functional selectivity" (also called ligand-directed receptor trafficking, stimulus trafficking, biased agonism, biased signalling), and agonist intervention with functional selectivity may improve the therapy. Many commercially available drugs with beneficial efficacy also show various undesirable side effects. Further studies of biased signalling might facilitate our understanding of the side effects of current drugs and take us to new avenues to efficiently design pathway-specific medications.

  14. A Comparison of Stimulus-Stimulus Pairing, Standard Echoic Training, and Control Procedures on the Vocal Behavior of Children with Autism

    ERIC Educational Resources Information Center

    Stock, Richard A.; Schulze, Kimberly A.; Mirenda, Pat

    2008-01-01

    An alternating treatments design was employed to compare the effect of stimulus-stimulus pairing, standard echoic training, and a control condition on the vocal behavior of 3 preschoolers with autism. Data were recorded during pre- and postsession observations. During the stimulus-stimulus pairing condition, the experimenter's vocal model was…

  15. Resurgence: Response competition, stimulus control, and reinforcer control.

    PubMed

    Podlesnik, Christopher A; Kelley, Michael E

    2014-09-01

    Resurgence is the relapse of a previously reinforced and then extinguished target response when extinguishing a more recently reinforced alternative response. We designed the present study to assess the contribution of stimulus-control and reinforcer-control processes in determining resurgence. In a modified resurgence procedure, we removed the alternative discriminative stimulus signaling alternative reinforcement when extinguishing the alternative response. This produced more abrupt resurgence of target responding than in a typical resurgence procedure maintaining the alternative discriminative stimulus when extinguishing the alternative response. The overall amount of resurgence did not differ. Importantly, a "renewal" control added and removed the alternative stimulus during extinction, identically as in the modified resurgence procedure. However, alternative responding was never reinforced, which produced no relapse of target responding. Therefore, the more abrupt resurgence with the modified procedure than with the typical procedure suggests removing the alternative stimulus reduced the competition between alternative and target responding. These findings revealed the importance of adding and removing alternative reinforcement in producing resurgence (reinforcer control) but little influence of simply adding and removing the alternative stimulus (stimulus control). These data suggest that clinicians should consider the long-term availability of the alternative response option when developing differential-reinforcement interventions.

  16. The formation of visual stimulus equivalences in children.

    PubMed Central

    Lazar, R M; Davis-Lang, D; Sanchez, L

    1984-01-01

    Four normal children were presented a series of matching-to-sample tasks, using five sets of visual stimuli designated A, B, C, D, and E. Stimulus equivalences were established by matching stimuli from one set to those from another set. Each set consisted of three stimuli, so matching set A to set D meant that each stimulus in set A served as a sample with all three stimuli in set D as comparisons. Subjects were first taught AD and DC matching and were then able to perform AC/CA matching without additional training. After ED was taught directly, CE/EC and AE/EA performances emerged. Following CB training, three new equivalences were demonstrated: AB/BA, EB/BE, and DB/BD. Oral naming of each stimulus showed that subjects had not assigned a common label to stimuli in the same class, indicating that naming is not necessary for the formation of stimulus equivalences. The absence of response mediation suggests that matching to sample can form direct stimulus-stimulus associations. The data also provide support for the notion that generative performances are outcomes of existing stimulus-control relationships. PMID:6736856

  17. Resurgence: Response competition, stimulus control, and reinforcer control.

    PubMed

    Podlesnik, Christopher A; Kelley, Michael E

    2014-09-01

    Resurgence is the relapse of a previously reinforced and then extinguished target response when extinguishing a more recently reinforced alternative response. We designed the present study to assess the contribution of stimulus-control and reinforcer-control processes in determining resurgence. In a modified resurgence procedure, we removed the alternative discriminative stimulus signaling alternative reinforcement when extinguishing the alternative response. This produced more abrupt resurgence of target responding than in a typical resurgence procedure maintaining the alternative discriminative stimulus when extinguishing the alternative response. The overall amount of resurgence did not differ. Importantly, a "renewal" control added and removed the alternative stimulus during extinction, identically as in the modified resurgence procedure. However, alternative responding was never reinforced, which produced no relapse of target responding. Therefore, the more abrupt resurgence with the modified procedure than with the typical procedure suggests removing the alternative stimulus reduced the competition between alternative and target responding. These findings revealed the importance of adding and removing alternative reinforcement in producing resurgence (reinforcer control) but little influence of simply adding and removing the alternative stimulus (stimulus control). These data suggest that clinicians should consider the long-term availability of the alternative response option when developing differential-reinforcement interventions. PMID:25125267

  18. Why the "stimulus-error" did not go away.

    PubMed

    Chirimuuta, M

    2016-04-01

    Psychologists in the early years of the discipline were much concerned with the stimulus-error. Roughly, this is the problem encountered in introspective experiments when subjects are liable to frame their perceptual reports in terms of what they know of the stimulus, instead of just drawing on their perceptual experiences as they are supposedly felt. "Introspectionist" psychologist E. B. Titchener and his student E. G. Boring both argued in the early 20th century that the stimulus-error is a serious methodological pit-fall. While many of the theoretical suppositions motivating Titchener and Boring have been unfashionable since the rise of behaviourism, the stimulus-error brings our attention to one matter of perennial importance to psychophysics and the psychology of perception. This is the fact that subjects are liable to give different kinds of perceptual reports in response to the same stimulus. I discuss attempts to control for variable reports in recent experimental work on colour and lightness constancy, and the disputes that have arisen over which kinds of reports are legitimate. Some contemporary psychologists do warn us against a stimulus-error, even though they do not use this terminology. I argue that concern over the stimulus-error is diagnostic of psychologists' deep theoretical commitments, such as their conception of sensation, or their demarcation of perception from cognition. I conclude by discussing the relevance of this debate to current philosophy of perception. PMID:27083082

  19. Stimulus configuration and location in the visual field affect appetitive responses by the praying mantis, Sphodromantis lineola (Burr.).

    PubMed

    Prete, F R

    1993-01-01

    Adult female praying mantises, Sphodromantis lineola (Burr.), were presented with computer-generated black rectangular stimuli that moved horizontally or vertically at 82 deg/s against a homogeneous white background. Both stimulus configuration (orientation in relation to direction) and the retinal location of the stimulus image affected the rate at which mantises responded appetitively (approached or struck at the stimulus). Mantises responded most to square stimuli (12.5 deg x 12.5 deg) when they moved horizontally or vertically through, or horizontally at 24.5 deg below the center of their visual field. Mantises also responded most to vertically (vs. horizontally) oriented rectangular stimuli (12.5 deg x 47 deg) that moved through their visual-field center, irrespective of whether the stimuli moved downward or horizontally. Upward moving stimuli elicited intermediate amounts of behavior with no configuration preference. Mantises did not demonstrate a configuration preference when rectangular stimuli moved > or = 24.5 deg outside of the visual-field center. Furthermore, mantises responded very little and demonstrated no configuration preferences to stimuli that moved less than approximately 83 deg through their visual field even if the stimuli moved through the visual-field center. PMID:8257673

  20. Reflex facilitation of the rabbit nictitating membrane response by an auditory stimulus as a function of interstimulus interval.

    PubMed

    Weisz, D J; Walts, C

    1990-02-01

    The ability of an auditory stimulus to facilitate the amplitude and latency of the unconditioned nictitating membrane (NM) response in rabbits was investigated over a wide range of interstimulus intervals (ISIs) for both delay (Experiments 1-4) and trace (Experiments 3 and 4) procedures. The auditory stimulus was a 1000-Hz tone (T) at either 85 or 95 dB, and the reflex-eliciting stimulus was a 2.0 psi (pounds per square inch) corneal air puff (AP). The results indicate that (a) robust facilitation of the NM response, as measured by an increased amplitude and a reduced latency, can be obtained at long ISIs (2,000-32,000 ms); (b) increasing the tone intensity can increase reflex facilitation of the peak amplitude; (c) at comparable ISIs, delay procedures produce more facilitation of both amplitude and latency than do trace procedures; and (d) when trace procedures are used, amplitude and latency facilitation by a 125-ms tone follows an inverted U-shaped ISI function in which facilitation peaks between 125 and 500 ms, rapidly decreases between 1,000 and 2,000 ms, and disappears by 4,000 ms.

  1. Neuronal correlates of the visually elicited escape response of the crab Chasmagnathus upon seasonal variations, stimuli changes and perceptual alterations.

    PubMed

    Sztarker, Julieta; Tomsic, Daniel

    2008-06-01

    When confronted with predators, animals are forced to take crucial decisions such as the timing and manner of escape. In the case of the crab Chasmagnathus, cumulative evidence suggests that the escape response to a visual danger stimulus (VDS) can be accounted for by the response of a group of lobula giant (LG) neurons. To further investigate this hypothesis, we examined the relationship between behavioral and neuronal activities within a variety of experimental conditions that affected the level of escape. The intensity of the escape response to VDS was influenced by seasonal variations, changes in stimulus features, and whether the crab perceived stimuli monocularly or binocularly. These experimental conditions consistently affected the response of LG neurons in a way that closely matched the effects observed at the behavioral level. In other words, the intensity of the stimulus-elicited spike activity of LG neurons faithfully reflected the intensity of the escape response. These results support the idea that the LG neurons from the lobula of crabs are deeply involved in the decision for escaping from VDS.

  2. Introducing Forum Theatre to Elicit and Advocate Children's Views

    ERIC Educational Resources Information Center

    Hammond, Nick

    2013-01-01

    Eliciting and advocating the voice of the child remains at the heart of international political agenda and also remains a central role for educational psychologists (EPs). Previous research indicates that EPs tend to use language-based methods for eliciting and advocating views of children. However, these approaches are often limited. Taking a…

  3. Freeze or Flee? Negative Stimuli Elicit Selective Responding

    ERIC Educational Resources Information Center

    Estes, Zachary; Verges, Michelle

    2008-01-01

    Humans preferentially attend to negative stimuli. A consequence of this automatic vigilance for negative valence is that negative words elicit slower responses than neutral or positive words on a host of cognitive tasks. Some researchers have speculated that negative stimuli elicit a general suppression of motor activity, akin to the freezing…

  4. Science Teachers' Elicitation Practices: Insights for Formative Assessment

    ERIC Educational Resources Information Center

    Ateh, Comfort M.

    2015-01-01

    In evaluating teachers' instructional decisions during instruction, it is clear that the nature of their elicitation is crucial for student learning. When instructional decisions are informed by information about students' conceptual understanding, significant learning is possible. This article examined the elicitation practices of two high school…

  5. Elicited Emotions and Cognitive Functioning in Preschool Children

    ERIC Educational Resources Information Center

    Blau, Rivka; Klein, Pnina S.

    2010-01-01

    In this study, the effects of eliciting positive and negative emotions on various cognitive functions of four- to five-year-old preschool children were examined. Emotions were elicited through presentations of "happy" and "sad" video clips, before the children performed the cognitive tasks. Behavioural (facial expressions) and physiological (heart…

  6. Goal-directed and transfer-cue-elicited drug-seeking are dissociated by pharmacotherapy: evidence for independent additive controllers.

    PubMed

    Hogarth, Lee

    2012-07-01

    According to contemporary learning theory, drug-seeking behavior reflects the summation of 2 dissociable controllers. Whereas goal-directed drug-seeking is determined by the expected current incentive value of the drug, stimulus-elicited drug-seeking is determined by the expected probability of the drug independently of its current incentive value, and these 2 controllers contribute additively to observed drug-seeking. One applied prediction of this model is that smoking cessation pharmacotherapies selectively attenuate tonic but not cue-elicited craving because they downgrade the expected incentive value of the drug but leave expected probability intact. To test this, the current study examined whether nicotine replacement therapy (NRT) nasal spray would modify goal-directed tobacco choice in a human outcome devaluation procedure, but leave cue-elicited tobacco choice in a Pavlovian to instrumental transfer (PIT) procedure intact. Smokers (N= 96) first underwent concurrent choice training in which 2 responses earned tobacco or chocolate points, respectively. Participants then ingested either NRT nasal spray (1 mg) or chocolate (147 g) to devalue 1 outcome. Concurrent choice was then tested again in extinction to measure goal-directed control of choice, and in a PIT test to measure the extent to which tobacco and chocolate stimuli enhanced choice of the same outcome. It was found that NRT modified tobacco choice in the extinction test but not the extent to which the tobacco stimulus enhanced choice of the tobacco outcome in the PIT test. This dissociation suggests that the propensity to engage in drug-seeking is determined independently by the expected value and probability of the drug, and that pharmacotherapy has partial efficacy because it selectively effects expected drug value.

  7. Goal-directed and transfer-cue-elicited drug-seeking are dissociated by pharmacotherapy: evidence for independent additive controllers.

    PubMed

    Hogarth, Lee

    2012-07-01

    According to contemporary learning theory, drug-seeking behavior reflects the summation of 2 dissociable controllers. Whereas goal-directed drug-seeking is determined by the expected current incentive value of the drug, stimulus-elicited drug-seeking is determined by the expected probability of the drug independently of its current incentive value, and these 2 controllers contribute additively to observed drug-seeking. One applied prediction of this model is that smoking cessation pharmacotherapies selectively attenuate tonic but not cue-elicited craving because they downgrade the expected incentive value of the drug but leave expected probability intact. To test this, the current study examined whether nicotine replacement therapy (NRT) nasal spray would modify goal-directed tobacco choice in a human outcome devaluation procedure, but leave cue-elicited tobacco choice in a Pavlovian to instrumental transfer (PIT) procedure intact. Smokers (N= 96) first underwent concurrent choice training in which 2 responses earned tobacco or chocolate points, respectively. Participants then ingested either NRT nasal spray (1 mg) or chocolate (147 g) to devalue 1 outcome. Concurrent choice was then tested again in extinction to measure goal-directed control of choice, and in a PIT test to measure the extent to which tobacco and chocolate stimuli enhanced choice of the same outcome. It was found that NRT modified tobacco choice in the extinction test but not the extent to which the tobacco stimulus enhanced choice of the tobacco outcome in the PIT test. This dissociation suggests that the propensity to engage in drug-seeking is determined independently by the expected value and probability of the drug, and that pharmacotherapy has partial efficacy because it selectively effects expected drug value. PMID:22823420

  8. The specificity of stimulus-specific adaptation in human auditory cortex increases with repeated exposure to the adapting stimulus.

    PubMed

    Briley, Paul M; Krumbholz, Katrin

    2013-12-01

    The neural response to a sensory stimulus tends to be more strongly reduced when the stimulus is preceded by the same, rather than a different, stimulus. This stimulus-specific adaptation (SSA) is ubiquitous across the senses. In hearing, SSA has been suggested to play a role in change detection as indexed by the mismatch negativity. This study sought to test whether SSA, measured in human auditory cortex, is caused by neural fatigue (reduction in neural responsiveness) or by sharpening of neural tuning to the adapting stimulus. For that, we measured event-related cortical potentials to pairs of pure tones with varying frequency separation and stimulus onset asynchrony (SOA). This enabled us to examine the relationship between the degree of specificity of adaptation as a function of frequency separation and the rate of decay of adaptation with increasing SOA. Using simulations of tonotopic neuron populations, we demonstrate that the fatigue model predicts independence of adaptation specificity and decay rate, whereas the sharpening model predicts interdependence. The data showed independence and thus supported the fatigue model. In a second experiment, we measured adaptation specificity after multiple presentations of the adapting stimulus. The multiple adapters produced more adaptation overall, but the effect was more specific to the adapting frequency. Within the context of the fatigue model, the observed increase in adaptation specificity could be explained by assuming a 2.5-fold increase in neural frequency selectivity. We discuss possible bottom-up and top-down mechanisms of this effect.

  9. The shaping of social perception by stimulus and knowledge cues to human animacy

    PubMed Central

    Ramsey, Richard; Liepelt, Roman; Prinz, Wolfgang; Hamilton, Antonia F. de C.

    2016-01-01

    Although robots are becoming an ever-growing presence in society, we do not hold the same expectations for robots as we do for humans, nor do we treat them the same. As such, the ability to recognize cues to human animacy is fundamental for guiding social interactions. We review literature that demonstrates cortical networks associated with person perception, action observation and mentalizing are sensitive to human animacy information. In addition, we show that most prior research has explored stimulus properties of artificial agents (humanness of appearance or motion), with less investigation into knowledge cues (whether an agent is believed to have human or artificial origins). Therefore, currently little is known about the relationship between stimulus and knowledge cues to human animacy in terms of cognitive and brain mechanisms. Using fMRI, an elaborate belief manipulation, and human and robot avatars, we found that knowledge cues to human animacy modulate engagement of person perception and mentalizing networks, while stimulus cues to human animacy had less impact on social brain networks. These findings demonstrate that self–other similarities are not only grounded in physical features but are also shaped by prior knowledge. More broadly, as artificial agents fulfil increasingly social roles, a challenge for roboticists will be to manage the impact of pre-conceived beliefs while optimizing human-like design. PMID:26644594

  10. The shaping of social perception by stimulus and knowledge cues to human animacy.

    PubMed

    Cross, Emily S; Ramsey, Richard; Liepelt, Roman; Prinz, Wolfgang; de C Hamilton, Antonia F

    2016-01-19

    Although robots are becoming an ever-growing presence in society, we do not hold the same expectations for robots as we do for humans, nor do we treat them the same. As such, the ability to recognize cues to human animacy is fundamental for guiding social interactions. We review literature that demonstrates cortical networks associated with person perception, action observation and mentalizing are sensitive to human animacy information. In addition, we show that most prior research has explored stimulus properties of artificial agents (humanness of appearance or motion), with less investigation into knowledge cues (whether an agent is believed to have human or artificial origins). Therefore, currently little is known about the relationship between stimulus and knowledge cues to human animacy in terms of cognitive and brain mechanisms. Using fMRI, an elaborate belief manipulation, and human and robot avatars, we found that knowledge cues to human animacy modulate engagement of person perception and mentalizing networks, while stimulus cues to human animacy had less impact on social brain networks. These findings demonstrate that self-other similarities are not only grounded in physical features but are also shaped by prior knowledge. More broadly, as artificial agents fulfil increasingly social roles, a challenge for roboticists will be to manage the impact of pre-conceived beliefs while optimizing human-like design.

  11. The shaping of social perception by stimulus and knowledge cues to human animacy.

    PubMed

    Cross, Emily S; Ramsey, Richard; Liepelt, Roman; Prinz, Wolfgang; de C Hamilton, Antonia F

    2016-01-19

    Although robots are becoming an ever-growing presence in society, we do not hold the same expectations for robots as we do for humans, nor do we treat them the same. As such, the ability to recognize cues to human animacy is fundamental for guiding social interactions. We review literature that demonstrates cortical networks associated with person perception, action observation and mentalizing are sensitive to human animacy information. In addition, we show that most prior research has explored stimulus properties of artificial agents (humanness of appearance or motion), with less investigation into knowledge cues (whether an agent is believed to have human or artificial origins). Therefore, currently little is known about the relationship between stimulus and knowledge cues to human animacy in terms of cognitive and brain mechanisms. Using fMRI, an elaborate belief manipulation, and human and robot avatars, we found that knowledge cues to human animacy modulate engagement of person perception and mentalizing networks, while stimulus cues to human animacy had less impact on social brain networks. These findings demonstrate that self-other similarities are not only grounded in physical features but are also shaped by prior knowledge. More broadly, as artificial agents fulfil increasingly social roles, a challenge for roboticists will be to manage the impact of pre-conceived beliefs while optimizing human-like design. PMID:26644594

  12. Stimulus information contaminates summation tests of independent neural representations of features

    NASA Technical Reports Server (NTRS)

    Shimozaki, Steven S.; Eckstein, Miguel P.; Abbey, Craig K.

    2002-01-01

    Many models of visual processing assume that visual information is analyzed into separable and independent neural codes, or features. A common psychophysical test of independent features is known as a summation study, which measures performance in a detection, discrimination, or visual search task as the number of proposed features increases. Improvement in human performance with increasing number of available features is typically attributed to the summation, or combination, of information across independent neural coding of the features. In many instances, however, increasing the number of available features also increases the stimulus information in the task, as assessed by an optimal observer that does not include the independent neural codes. In a visual search task with spatial frequency and orientation as the component features, a particular set of stimuli were chosen so that all searches had equivalent stimulus information, regardless of the number of features. In this case, human performance did not improve with increasing number of features, implying that the improvement observed with additional features may be due to stimulus information and not the combination across independent features.

  13. Task-irrelevant stimulus salience affects visual search.

    PubMed

    Lamy, Dominique; Zoaris, Loren

    2009-05-01

    The relative contributions of stimulus salience and task-related goals in guiding attention remain an issue of debate. Several studies have demonstrated that top-down factors play an important role, as they often override capture by salient irrelevant objects. However, Yantis and Egeth [Yantis, S., & Egeth, H. E. (1999). On the distinction between visual salience and stimulus-driven attentional capture. Journal of Experimental Psychology: Human Perception and Performance, 25, 661-676.] have made the more radical claim that salience plays no role in visual search unless the observer adopts an attentional set for singletons or "singleton-detection mode". We reexamine their claim while disentangling effects of stimulus salience from effects of attentional set and inter-trial repetition. The results show that stimulus salience guides attention even when salience is task irrelevant.

  14. Nanoscale theranostics for physical stimulus-responsive cancer therapies.

    PubMed

    Chen, Qian; Ke, Hengte; Dai, Zhifei; Liu, Zhuang

    2015-12-01

    Physical stimulus-responsive therapies often employing multifunctional theranostic agents responsive to external physical stimuli such as light, magnetic field, ultra-sound, radiofrequency, X-ray, etc., have been widely explored as novel cancer therapy strategies, showing encouraging results in many pre-clinical animal experiments. Unlike conventional cancer chemotherapy which often accompanies with severe toxic side effects, physical stimulus-responsive agents usually are non-toxic by themselves and would destruct cancer cells only under specific external stimuli, and thus could offer greatly reduced toxicity and enhanced treatment specificity. In addition, physical stimulus-responsive therapies can also be combined with other traditional therapeutics to achieve synergistic anti-tumor effects via a variety of mechanisms. In this review, we will summarize the latest progress in the development of physical stimulus-responsive therapies, and discuss the important roles of nanoscale theranostic agents involved in those non-conventional therapeutic strategies. PMID:26410788

  15. Signalization and stimulus-substitution in Pavlov's theory of conditioning.

    PubMed

    García-Hoz, Víctor

    2003-11-01

    The concept of conditioning as signalization proposed by Ivan P. Pavlov (1927, 1928) is studied in relation to the theory of stimulus-substitution, which is also attributed to him. In the so-called theory of stimulus-substitution a distinction must be made between an empirical principle of substitution and an actual theory of substitution, which can adopt different forms. The Pavlovian theory of substitution--which conceives substitution as a substitution of the unconditioned stimulus (US) by the conditioned stimulus (CS) in the activation of the representation of the former--can be understood as an explanation or model of signalization. Signalization and substitution are answers to different questions, and the level of analysis to which signalization corresponds, is that which concerns the nature of conditioning as an operation of the animal in the environment.

  16. Probability effects on stimulus evaluation and response processes

    NASA Technical Reports Server (NTRS)

    Gehring, W. J.; Gratton, G.; Coles, M. G.; Donchin, E.

    1992-01-01

    This study investigated the effects of probability information on response preparation and stimulus evaluation. Eight subjects responded with one hand to the target letter H and with the other to the target letter S. The target letter was surrounded by noise letters that were either the same as or different from the target letter. In 2 conditions, the targets were preceded by a warning stimulus unrelated to the target letter. In 2 other conditions, a warning letter predicted that the same letter or the opposite letter would appear as the imperative stimulus with .80 probability. Correct reaction times were faster and error rates were lower when imperative stimuli confirmed the predictions of the warning stimulus. Probability information affected (a) the preparation of motor responses during the foreperiod, (b) the development of expectancies for a particular target letter, and (c) a process sensitive to the identities of letter stimuli but not to their locations.

  17. Resurgence of derived stimulus relations: replication and extensions.

    PubMed

    Doughty, Adam H; Kastner, Rebecca M; Bismark, Bryan D

    2011-01-01

    Resurgence typically refers to the recovery of a previously reinforced response when a more recently reinforced response is extinguished. Under conditions of punishment, Wilson and Hayes (1996) observed the recovery of derived stimulus relations that never had been correlated with differential consequences. The present study systematically replicated the findings of Wilson and Hayes by observing the recovery of derived stimulus relations under extinction conditions and with an additional equivalence class. College students received arbitrary-matching-to-sample training in Phase 1 that resulted in four 4-member stimulus-equivalence classes. These derived relations were not correlated with differential consequences. In Phase 2, with the same stimuli, the students received training that resulted in four different 4-member stimulus-equivalence classes. After the emergence and reinforcement of the latter derived relations, their extinction generated the recurrence of the derived relations from Phase 1. The implications of these findings for conceptualizing resurgence are discussed. PMID:20801199

  18. Combining stimulus fading, reinforcement, and extinction to treat food refusal.

    PubMed

    Freeman, K A; Piazza, C C

    1998-01-01

    The food refusal of a 6-year-old girl with destructive behavior was treated using stimulus fading, reinforcement, and escape extinction. Intake increased and compliance with prompting procedures remained relatively stable despite the increased consumption requirement.

  19. Retinal imaging with virtual reality stimulus for studying Salticidae retinas

    NASA Astrophysics Data System (ADS)

    Schiesser, Eric; Canavesi, Cristina; Long, Skye; Jakob, Elizabeth; Rolland, Jannick P.

    2014-12-01

    We present a 3-path optical system for studying the retinal movement of jumping spiders: a visible OLED virtual reality system presents stimulus, while NIR illumination and imaging systems observe retinal movement.

  20. Signaling of the strongest stimulus in the owl optic tectum.

    PubMed

    Mysore, Shreesh P; Asadollahi, Ali; Knudsen, Eric I

    2011-04-01

    Essential to the selection of the next target for gaze or attention is the ability to compare the strengths of multiple competing stimuli (bottom-up information) and to signal the strongest one. Although the optic tectum (OT) has been causally implicated in stimulus selection, how it computes the strongest stimulus is unknown. Here, we demonstrate that OT neurons in the barn owl systematically encode the relative strengths of simultaneously occurring stimuli independently of sensory modality. Moreover, special "switch-like" responses of a subset of neurons abruptly increase when the stimulus inside their receptive field becomes the strongest one. Such responses are not predicted by responses to single stimuli and, indeed, are eliminated in the absence of competitive interactions. We demonstrate that this sensory transformation substantially boosts the representation of the strongest stimulus by creating a binary discrimination signal, thereby setting the stage for potential winner-take-all target selection for gaze and attention. PMID:21471353

  1. Signalization and stimulus-substitution in Pavlov's theory of conditioning.

    PubMed

    García-Hoz, Víctor

    2003-11-01

    The concept of conditioning as signalization proposed by Ivan P. Pavlov (1927, 1928) is studied in relation to the theory of stimulus-substitution, which is also attributed to him. In the so-called theory of stimulus-substitution a distinction must be made between an empirical principle of substitution and an actual theory of substitution, which can adopt different forms. The Pavlovian theory of substitution--which conceives substitution as a substitution of the unconditioned stimulus (US) by the conditioned stimulus (CS) in the activation of the representation of the former--can be understood as an explanation or model of signalization. Signalization and substitution are answers to different questions, and the level of analysis to which signalization corresponds, is that which concerns the nature of conditioning as an operation of the animal in the environment. PMID:14628703

  2. The Stimulus Movement Effect: Allocation of Attention or Artifact?

    NASA Technical Reports Server (NTRS)

    Washburn, David A.

    1993-01-01

    In previous reports, including one by the author, learning has been shown to benefit by having discriminanda move rather than remain stationary. This stimulus movement effect might be attributed to several theoretical mechanisms, including attention, topological memory, and exposure duration. The series of experiments reported in this article was designed to Contrast these potential explanatory factors. Ten rhesus monkeys (Macaca mulatta) were tested on a variety of computerized tasks in which the stimuli remained stationary, flashed, or moved at systematically varied speeds. Performance was significantly best when the sample stimulus moved quickly and was poorest when the stimulus remained stationary. Further analysis of these data and other previously published data revealed that the distribution of the stimulus movement effect across trials supported an attention allocation interpretation.

  3. A preliminary report on the use of virtual reality technology to elicit craving and cue reactivity in cocaine dependent individuals.

    PubMed

    Saladin, Michael E; Brady, Kathleen T; Graap, Ken; Rothbaum, Barbara Olasov

    2006-10-01

    In the present feasibility study, we developed a 3-dimensional virtual "crack" cocaine environment and evaluated the environment's ability to elicit subjective craving and cue reactivity (i.e., subjective emotional responding, heart rate and skin conductance) in 11 crack cocaine dependent individuals. Each of the seven 3-D crack cocaine scenes in the cocaine environment depicted actors engaging in a range of using-related behaviors (i.e., smoking crack) whereas the neutral environment contained scenes depicted 3-D aquariums with active aquatic life (baseline measures were obtained following immersion in the neutral environment). Results indicated that craving was significantly elevated during the cocaine-related scenes as compared to baseline. Craving varied by scene content, with scenes depicting active cocaine use eliciting the highest levels of craving. Heart rate was significantly higher in four of the scenes with drug use content and positive affect (i.e., happiness) ratings were significantly lower during cocaine scenes as compared to baseline. Overall, the results suggest that a standardized and stimulus rich virtual reality environment effectively elicits craving and physiologic reactivity. Such technology has potential utility in the development and refinement of exposure-based behavioral and pharmacological interventions for substance use disorders.

  4. Roll aftereffects: influence of tilt and inter-stimulus interval.

    PubMed

    Crane, Benjamin T

    2012-11-01

    A theme in sensory perception is that exposure to a stimulus causes perception of subsequent stimuli to be shifted in the opposite direction. Such phenomenon is known as aftereffect and has been extensively described in the visual system as well as recently described for the vestibular system during translation. It is known from aviation studies that after a maneuver in roll, pilots can experience a false perception of roll in the opposite direction. The magnitude and duration of this effect as well as the potential influence of the gravity vector have not previously been defined. In the current paper this roll aftereffect (RAE) is examined in response to whole-body roll about an earth-horizontal axis in eight healthy human subjects. The peak velocity of a 0.5-s-duration roll was varied based on previous responses to find the point where subjects perceived no motion. Without a preceding stimulus, the starting position (upright, 9° left, or 9° right) did not influence roll perception. The RAE was measured in a completely dark room using an adapting (first interval) stimulus consisting of 9° of roll over 1.5 s (peak velocity, 12°/s), delivered 0.5, 3, or 6 s prior to test (second interval) stimulus. A significant RAE was seen in all subjects. Half a second after the adapting stimulus, a test stimulus had to be on average 1.5 ± 0.4°/s in the opposite direction to be perceived as stationary. When the subject remained upright after the adapting stimulus, the RAE diminished with time, although it remained significantly larger at 3 and 6 s when the subject remained tilted after the adapting stimulus. These data demonstrate that roll perception can be influenced by small preceding stimuli and tilt causes a persistence of the RAE.

  5. Overselective stimulus control in residential school students with intellectual disabilities.

    PubMed

    Dickson, Chata A; Wang, Sharon S; Lombard, Kristin M; Dube, William V

    2006-01-01

    Overselective stimulus control was assessed in 29 students at residential schools for individuals with developmental disabilities. Overselectivity testing included three different delayed identity matching-to-sample tasks. Sample stimuli for the Form/Color Test were nine possible combinations of three colors and three forms. On each trial, the S+ stimulus was identical to the sample, one S- was the same color as the sample but a different form, and the other S- was the same form but a different color. Sample stimuli for the Two-Sample Test were two alphanumeric characters. The S+ stimulus was identical to one of the sample stimuli, and two S- stimuli were characters different from both samples. Sample stimuli for the Faces Test were six digital images of adult faces. On each trial, the S+ stimulus was identical to the sample, one S- stimulus was a non-matching face to which one sample feature had been added (e.g., an identical hat or scarf), and the other S- stimulus was an unaltered non-matching face. All participants were also tested with the Peabody Picture Vocabulary Test III (PPVT) and the Autism Diagnostic Observation Schedule (ADOS). Results indicated overselective stimulus control on at least one test for 18 of the 29 participants. Overselectivity (a) was distributed across a range of PPVT mental age equivalent scores from <1.75 to 8.83; (b) was more likely in individuals with higher ADOS scores; (c) was most likely on the Two-Sample Test; and (d) was found in five individuals on more than one of the tests. Thus, overselective stimulus control may occur across a range of characteristics typical for students who attend residential special-education programs.

  6. Using Software to Elicit User Needs for Clinical Research Visit Scheduling

    PubMed Central

    Weng, Chunhua; Boland, Mary Regina; So, Yat; Rusanov, Alexander; Lopez, Carlos; Steinman, Richard; Busacca, Linda; Bakken, Suzanne; Bigger, J Thomas

    2014-01-01

    User needs understanding is critical for developing useful and usable clinical research decision support. Existing methods largely depend on self-reporting and often fail to elicit implicit or fine-grained user needs. We hypothesized that functional software would address this problem by presenting to users existing technology while simultaneously encouraging users to optimize workflow. Using clinical research visit scheduling as an example, we used a piece of software under development that was called IMPACT to reveal user needs iteratively. The identified user needs explained why most clinical research coordinators still rely on paper to schedule clinical research visits. The common user needs themes such as information completeness for software to be useful may generalize to other clinical decision support. This paper contributes valuable firsthand knowledge about user needs for decision support for clinical research visit scheduling among clinical research coordinators and a generalizable methodology for collecting and analyzing software usage data to inform user needs elicitation. PMID:25954586

  7. The role of stimulus uncertainty in speech perception

    NASA Astrophysics Data System (ADS)

    Kewley-Port, Diane

    2001-05-01

    Among the important experimental factors that affect psychophysical measurements of speech perception is stimulus uncertainty. Charles Watson has defined stimulus uncertainty as variation in stimulus parameters from trial to trial and demonstrated its highly degrading effects on a variety of complex auditory signals. Watson, Kelley, and Wroton showed large (×10) elevation of frequency-discrimination thresholds for ``word-length tonal patterns'' under high uncertainty conditions [J. Acoust. Soc. Am. 60, 1176-1186 (1976)]. Investigations of speech, such as the perception of VOT (voice onset time) in stops [Kewley-Port, Watson, and Foyle, J. Acoust. Soc. Am. 83, 1113-1145 (1988)] and discrimination of vowel formants [Kewley-Port, J. Acoust. Soc. Am. 110 (2001)], have also demonstrated the systematic and profound effects of higher levels of stimulus uncertainty. This presentation will discuss extensions of the concept of stimulus uncertainty that demonstrate the degrading effects of the variability in more natural speech (versus synthetic speech) and longer phonetic context (including sentences) on vowel formant discrimination. Results from normal-hearing and hearing-impaired listeners demonstrating similar detrimental effects of high stimulus uncertainty will also be presented. [Research supported by NIH-NIDCD.

  8. FMRI repetition suppression for voices is modulated by stimulus expectations.

    PubMed

    Andics, Attila; Gál, Viktor; Vicsi, Klára; Rudas, Gábor; Vidnyánszky, Zoltán

    2013-04-01

    According to predictive coding models of sensory processing, stimulus expectations have a profound effect on sensory cortical responses. This was supported by experimental results, showing that fMRI repetition suppression (fMRI RS) for face stimuli is strongly modulated by the probability of stimulus repetitions throughout the visual cortical processing hierarchy. To test whether processing of voices is also affected by stimulus expectations, here we investigated the effect of repetition probability on fMRI RS in voice-selective cortical areas. Changing ('alt') and identical ('rep') voice stimulus pairs were presented to the listeners in blocks, with a varying probability of alt and rep trials across blocks. We found auditory fMRI RS in the nonprimary voice-selective cortical regions, including the bilateral posterior STS, the right anterior STG and the right IFC, as well as in the IPL. Importantly, fMRI RS effects in all of these areas were strongly modulated by the probability of stimulus repetition: auditory fMRI RS was reduced or not present in blocks with low repetition probability. Our results revealed that auditory fMRI RS in higher-level voice-selective cortical regions is modulated by repetition probabilities and thus suggest that in audition, similarly to the visual modality, processing of sensory information is shaped by stimulus expectation processes. PMID:23268783

  9. Stimulus probability effects on temporal bisection performance of mice (Mus musculus).

    PubMed

    Akdoğan, Başak; Balcı, Fuat

    2016-01-01

    In the temporal bisection task, participants classify experienced stimulus durations as short or long based on their temporal similarity to previously learned reference durations. Temporal decision making in this task should be influenced by the experienced probabilities of the reference durations for adaptiveness. In this study, we tested the temporal bisection performance of mice (Mus musculus) under different short and long reference duration probability conditions implemented across two experimental phases. In Phase 1, the proportion of reference durations (compared to probe durations) was 0.5, whereas in Phase 2 it was increased to 0.8 to further examine the adjustment of choice behavior with more frequent reference duration presentations (under higher reinforcement rate). Our findings suggest that mice developed adaptive biases in their choice behaviors. These adjustments in choice behavior were nearly optimal as the mice maximized their gain to a great extent which required them to monitor stimulus probabilities as well as the level of variability in their temporal judgments. We further found that short but not long categorization response times were sensitive to stimulus probability manipulations, which in turn suggests an asymmetry between short and long categorizations. Finally, we investigated the latent decision processes underlying the bias manifested in subjects' choice behavior within the diffusion model framework. Our results revealed that probabilistic information influenced the starting point and the rate of evidence accumulation process. Overall, the stimulus probability effects on choice behavior were modulated by the reinforcement rate. Our findings illustrate that mice can adapt their temporal behaviors with respect to the probabilistic contingencies in the environment.

  10. Stimulus probability effects on temporal bisection performance of mice (Mus musculus).

    PubMed

    Akdoğan, Başak; Balcı, Fuat

    2016-01-01

    In the temporal bisection task, participants classify experienced stimulus durations as short or long based on their temporal similarity to previously learned reference durations. Temporal decision making in this task should be influenced by the experienced probabilities of the reference durations for adaptiveness. In this study, we tested the temporal bisection performance of mice (Mus musculus) under different short and long reference duration probability conditions implemented across two experimental phases. In Phase 1, the proportion of reference durations (compared to probe durations) was 0.5, whereas in Phase 2 it was increased to 0.8 to further examine the adjustment of choice behavior with more frequent reference duration presentations (under higher reinforcement rate). Our findings suggest that mice developed adaptive biases in their choice behaviors. These adjustments in choice behavior were nearly optimal as the mice maximized their gain to a great extent which required them to monitor stimulus probabilities as well as the level of variability in their temporal judgments. We further found that short but not long categorization response times were sensitive to stimulus probability manipulations, which in turn suggests an asymmetry between short and long categorizations. Finally, we investigated the latent decision processes underlying the bias manifested in subjects' choice behavior within the diffusion model framework. Our results revealed that probabilistic information influenced the starting point and the rate of evidence accumulation process. Overall, the stimulus probability effects on choice behavior were modulated by the reinforcement rate. Our findings illustrate that mice can adapt their temporal behaviors with respect to the probabilistic contingencies in the environment. PMID:26242608

  11. Does Hearing About Cancer Influence Stimulus Control? An Exploratory Study of Verbal Modulation of Stimulus Generalization.

    PubMed

    Critchfield, Thomas S; Reed, Derek D

    2016-06-01

    Participants first became familiar with an image showing moderate symptoms of the skin cancer melanoma. In a generalization test, they indicated whether images showing more and less pronounced symptoms were "like the original." Some groups (cancer context) were told that the images depicted melanoma and that the disease is deadly unless detected early. Control groups were not told what the images depicted. For control groups, generalization gradients were fairly typical of what is normally reported in the generalization literature, but for cancer context groups, gradients were shifted such that highly symptomatic moles were identified as "like the original" more than normal and subtly symptomatic ones were endorsed less than normal. These results may have implications for melanoma education efforts and, more generally, illustrate the possible importance of studying interactions between verbal behavior and primary stimulus control. PMID:27606221

  12. Assessment of nonlinear interactions in event-related potentials elicited by stimuli presented at short interstimulus intervals using single-trial data.

    PubMed

    Loizides, Charalambos; Achilleos, Achilleas; Iannetti, Gian Domenico; Mitsis, Georgios D

    2015-06-01

    The recording of brain event-related potentials (ERPs) is a widely used technique to investigate the neural basis of sensory perception and cognitive processing in humans. Due to the low magnitude of ERPs, averaging of several consecutive stimuli is typically employed to enhance the signal to noise ratio (SNR) before subsequent analysis. However, when the temporal interval between two consecutive stimuli is smaller than the latency of the main ERP peaks, i.e., when the stimuli are presented at a fast rate, overlaps between the corresponding ERPs may occur. These overlaps are usually dealt with by assuming that there is a simple additive superposition between the elicited ERPs and consequently performing algebraic waveform subtractions. Here, we test this assumption rigorously by providing a statistical framework that examines the presence of nonlinear additive effects between overlapping ERPs elicited by successive stimuli with short interstimulus intervals (ISIs). The results suggest that there are no nonlinear additive effects due to the time overlap per se but that, for the range of ISIs examined, the second ERP is modulated by the presence of the first stimulus irrespective of whether there is time overlap or not. In other words, two ERPs that overlap in time can still be written as an addition of two ERPs but with the second ERP being different from the first. This difference is also present in the case of nonoverlapping ERPs with short ISIs. The modulation effect elicited on the second ERP by the first stimulus is dependent on the ISI value.

  13. Dejittered spike-conditioned stimulus waveforms yield improved estimates of neuronal feature selectivity and spike-timing precision of sensory interneurons.

    PubMed

    Aldworth, Zane N; Miller, John P; Gedeon, Tomás; Cummins, Graham I; Dimitrov, Alexander G

    2005-06-01

    What is the meaning associated with a single action potential in a neural spike train? The answer depends on the way the question is formulated. One general approach toward formulating this question involves estimating the average stimulus waveform preceding spikes in a spike train. Many different algorithms have been used to obtain such estimates, ranging from spike-triggered averaging of stimuli to correlation-based extraction of "stimulus-reconstruction" kernels or spatiotemporal receptive fields. We demonstrate that all of these approaches miscalculate the stimulus feature selectivity of a neuron. Their errors arise from the manner in which the stimulus waveforms are aligned to one another during the calculations. Specifically, the waveform segments are locked to the precise time of spike occurrence, ignoring the intrinsic "jitter" in the stimulus-to-spike latency. We present an algorithm that takes this jitter into account. "Dejittered" estimates of the feature selectivity of a neuron are more accurate (i.e., provide a better estimate of the mean waveform eliciting a spike) and more precise (i.e., have smaller variance around that waveform) than estimates obtained using standard techniques. Moreover, this approach yields an explicit measure of spike-timing precision. We applied this technique to study feature selectivity and spike-timing precision in two types of sensory interneurons in the cricket cercal system. The dejittered estimates of the mean stimulus waveforms preceding spikes were up to three times larger than estimates based on the standard techniques used in previous studies and had power that extended into higher-frequency ranges. Spike timing precision was approximately 5 ms.

  14. Neural representation of stimulus-response associations during task preparation.

    PubMed

    Cookson, Savannah L; Hazeltine, Eliot; Schumacher, Eric H

    2016-10-01

    A partially informative cue presented before a stimulus can facilitate the production of the response. Prior information about an upcoming target can increase brain activity in both stimulus (c.f., Desimone and Duncan, 1995) and response (c.f., Leuthold et al., 1996) processing regions; however, it is unclear how the representation of the task might influence the recruitment of this network of task-relevant regions. In the current experiment, we employed an event-related fMRI design with a response cuing procedure to investigate whether S-R pairings jointly influence activity in stimulus- and response-specific processing areas during the presentation of a cue. Participants learned S-R mappings in which pictures of faces and places were paired with either left or right hand finger responses. On some trials, a cue provided partial information about the upcoming trial (e.g., that the trial would involve a face or place stimuli or a left or right hand response). Importantly, because different stimulus types were associated with each hand, any informative cue implicitly indicated both a stimulus type and response hand, allowing participants to represent the task as two distinct subtasks. Region-of-interest analyses at the cue event demonstrated a biasing of response processing regions for both stimulus- and response-related cues, as well as increased connectivity with the associated stimulus-processing regions. The results suggest that the cue results in the recruitment of just the task-relevant subnetwork on each trial. PMID:27527267

  15. Stimulus-evoked high frequency oscillations are present in neuronal networks on microelectrode arrays

    PubMed Central

    Hales, Chadwick M.; Zeller-Townson, Riley; Newman, Jonathan P.; Shoemaker, James T.; Killian, Nathan J.; Potter, Steve M.

    2012-01-01

    Pathological high frequency oscillations (250–600 Hz) are present in the brains of epileptic animals and humans. The etiology of these oscillations and how they contribute to the diseased state remains unclear. This work identifies the presence of microstimulation-evoked high frequency oscillations (250–400 Hz) in dissociated neuronal networks cultured on microelectrode arrays (MEAs). Oscillations are more apparent with higher stimulus voltages. As with in vivo studies, activity is isolated to a single electrode, however, the MEA provides improved spatial resolution with no spread of the oscillation to adjacent electrodes 200 μm away. Oscillations develop across four weeks in vitro. Oscillations still occur in the presence of tetrodotoxin and synaptic blockers, and they cause no apparent disruption in the ability of oscillation-presenting electrodes to elicit directly evoked action potentials (dAPs) or promote the spread of synaptic activity throughout the culture. Chelating calcium with ethylene glycol tetraacetic acid (EGTA) causes a temporal prolongation of the oscillation. Finally, carbenoxolone significantly reduces or eliminates the high frequency oscillations. Gap junctions may play a significant role in maintaining the oscillation given the inhibitory effect of carbenoxolone, the propagating effect of reduced calcium conditions and the isolated nature of the activity as demonstrated in previous studies. This is the first demonstration of stimulus-evoked high frequency oscillations in dissociated cultures. Unlike current models that rely on complex in vivo recording conditions, this work presents a simple controllable model in neuronal cultures on MEAs to further investigate how the oscillations occur at the molecular level and how they may contribute to the pathophysiology of disease. PMID:22615686

  16. Phenotypic assessment of THC discriminative stimulus properties in fatty acid amide hydrolase knockout and wildtype mice.

    PubMed

    Walentiny, D Matthew; Vann, Robert E; Wiley, Jenny L

    2015-06-01

    A number of studies have examined the ability of the endogenous cannabinoid anandamide to elicit Δ(9)-tetrahydrocannabinol (THC)-like subjective effects, as modeled through the THC discrimination paradigm. In the present study, we compared transgenic mice lacking fatty acid amide hydrolase (FAAH), the enzyme primarily responsible for anandamide catabolism, to wildtype counterparts in a THC discrimination procedure. THC (5.6 mg/kg) served as a discriminative stimulus in both genotypes, with similar THC dose-response curves between groups. Anandamide fully substituted for THC in FAAH knockout, but not wildtype, mice. Conversely, the metabolically stable anandamide analog O-1812 fully substituted in both groups, but was more potent in knockouts. The CB1 receptor antagonist rimonabant dose-dependently attenuated THC generalization in both groups and anandamide substitution in FAAH knockouts. Pharmacological inhibition of monoacylglycerol lipase (MAGL), the primary catabolic enzyme for the endocannabinoid 2-arachidonoylglycerol (2-AG), with JZL184 resulted in full substitution for THC in FAAH knockout mice and nearly full substitution in wildtypes. Quantification of brain endocannabinoid levels revealed expected elevations in anandamide in FAAH knockout mice compared to wildtypes and equipotent dose-dependent elevations in 2-AG following JZL184 administration. Dual inhibition of FAAH and MAGL with JZL195 resulted in roughly equipotent increases in THC-appropriate responding in both groups. While the notable similarity in THC's discriminative stimulus effects across genotype suggests that the increased baseline brain anandamide levels (as seen in FAAH knockout mice) do not alter THC's subjective effects, FAAH knockout mice are more sensitive to the THC-like effects of pharmacologically induced increases in anandamide and MAGL inhibition (e.g., JZL184).

  17. Electrically Elicited Visual Evoked Potentials in Argus II Retinal Implant Wearers

    PubMed Central

    Stronks, H. Christiaan; Barry, Michael P.; Dagnelie, Gislin

    2013-01-01

    Purpose. We characterized electrically elicited visual evoked potentials (eVEPs) in Argus II retinal implant wearers. Methods. eVEPs were recorded in four subjects, and analyzed by determining amplitude and latency of the first two positive peaks (P1 and P2). Subjects provided subjective feedback by rating the brightness and size of the phosphenes. We established eVEP input–output relationships, eVEP variability between and within subjects, the effect of stimulating different areas of the retina, and the maximal pulse rate to record eVEPs reliably. Results. eVEP waveforms had low signal-to-noise ratios, requiring long recording times and substantial signal processing. Waveforms varied between subjects, but showed good reproducibility and consistent parameter dependence within subjects. P2 amplitude overall was the most robust outcome measure and proved an accurate indicator of subjective threshold. Peak latencies showed small within-subject variability, yet their correlation with stimulus level and subjective rating were more variable than that of peak amplitudes. Pulse rates of up to 2/3 Hz resulted in reliable eVEP recordings. Perceived phosphene brightness declined over time, as reflected in P1 amplitude, but not in P2 amplitude or peak latencies. Stimulating-electrode location significantly affected P1 and P2 amplitude and latency, but not subjective percepts. Conclusions. While recording times and signal processing are more demanding than for standard visually evoked potential (VEP) recordings, the eVEP has proven to be a reliable tool to verify retinal implant functionality. eVEPs correlated with various stimulus parameters and with perceptual ratings. In view of these findings, eVEPs may become an important tool in functional investigations of retinal prostheses. (ClinicalTrials.gov number NCT00407602.) Dutch Abstract PMID:23611993

  18. Duration of the unconditioned stimulus in appetitive conditioning of honeybees differentially impacts learning, long-term memory strength, and the underlying protein synthesis

    PubMed Central

    Marter, Kathrin; Grauel, M. Katharina; Lewa, Carmen; Morgenstern, Laura; Buckemüller, Christina; Heufelder, Karin; Ganz, Marion

    2014-01-01

    This study examines the role of stimulus duration in learning and memory formation of honeybees (Apis mellifera). In classical appetitive conditioning honeybees learn the association between an initially neutral, conditioned stimulus (CS) and the occurrence of a meaningful stimulus, the unconditioned stimulus (US). Thereby the CS becomes a predictor for the US eliciting a conditioned response (CR). Here we study the role of US duration in classical conditioning by examining honeybees conditioned with different US durations. We quantify the CR during acquisition, memory retention, and extinction of the early long-term memory (eLTM), and examine the molecular mechanisms of eLTM by interfering with protein synthesis. We find that the US duration affects neither the probability nor the strength of the CR during acquisition, eLTM retention, and extinction 24 h after conditioning. However, we find that the resistance to extinction 24 h after conditioning is susceptible to protein synthesis inhibition depending on the US duration. We conclude that the US duration does not affect the predictability of the US but modulates the protein synthesis underlying the eLTM's strength. Thus, the US duration differentially impacts learning, eLTM strength, and its underlying protein synthesis. PMID:25403456

  19. Duration of the unconditioned stimulus in appetitive conditioning of honeybees differentially impacts learning, long-term memory strength, and the underlying protein synthesis.

    PubMed

    Marter, Kathrin; Grauel, M Katharina; Lewa, Carmen; Morgenstern, Laura; Buckemüller, Christina; Heufelder, Karin; Ganz, Marion; Eisenhardt, Dorothea

    2014-12-01

    This study examines the role of stimulus duration in learning and memory formation of honeybees (Apis mellifera). In classical appetitive conditioning honeybees learn the association between an initially neutral, conditioned stimulus (CS) and the occurrence of a meaningful stimulus, the unconditioned stimulus (US). Thereby the CS becomes a predictor for the US eliciting a conditioned response (CR). Here we study the role of US duration in classical conditioning by examining honeybees conditioned with different US durations. We quantify the CR during acquisition, memory retention, and extinction of the early long-term memory (eLTM), and examine the molecular mechanisms of eLTM by interfering with protein synthesis. We find that the US duration affects neither the probability nor the strength of the CR during acquisition, eLTM retention, and extinction 24 h after conditioning. However, we find that the resistance to extinction 24 h after conditioning is susceptible to protein synthesis inhibition depending on the US duration. We conclude that the US duration does not affect the predictability of the US but modulates the protein synthesis underlying the eLTM's strength. Thus, the US duration differentially impacts learning, eLTM strength, and its underlying protein synthesis.

  20. CCSI Risk Estimation: An Application of Expert Elicitation

    SciTech Connect

    Engel, David W.; Dalton, Angela C.

    2012-10-01

    The Carbon Capture Simulation Initiative (CCSI) is a multi-laboratory simulation-driven effort to develop carbon capture technologies with the goal of accelerating commercialization and adoption in the near future. One of the key CCSI technical challenges is representing and quantifying the inherent uncertainty and risks associated with developing, testing, and deploying the technology in simulated and real operational settings. To address this challenge, the CCSI Element 7 team developed a holistic risk analysis and decision-making framework. The purpose of this report is to document the CCSI Element 7 structured systematic expert elicitation to identify additional risk factors. We review the significance of and established approaches to expert elicitation, describe the CCSI risk elicitation plan and implementation strategies, and conclude by discussing the next steps and highlighting the contribution of risk elicitation toward the achievement of the overarching CCSI objectives.

  1. Spoonerisms as Sequencer Conflicts: Evidence from Artifically Elicited Errors

    ERIC Educational Resources Information Center

    Baars, Bernard J.; Motley, Michael T.

    1976-01-01

    Presents evidence that spoonerisms result from a conflict in word sequencing that carries through to phoneme sequencing, and in the process illustrates the use of some techniques for the experimental elicitation of spoonerisms. (Author/RK)

  2. The new vaccines: building viruses that elicit antitumor immunity

    PubMed Central

    Restifo, Nicholas P

    2007-01-01

    Whereas cancer cells are poor immunogens, some viruses are capable of eliciting powerful and lifelong immunity. Recombinant viruses and plasmid DNA encoding tumor-associated antigens can elicit powerful and specific immune responses that can be enhanced by the use of cytokines and costimulatory molecules. These immune responses have destroyed growing tumor cells in experimental animal models. For the first time, immunotherapeutic strategies that employ recombinant viruses are being tested in clinical trials with cancer patients. PMID:8902391

  3. Stimulus representation in SOP: I. Theoretical rationalization and some implications.

    PubMed

    Brandon, Susan E.; Vogel, Edgar H.; Wagner, Allan R.

    2003-04-28

    THE SOP MODEL [INFORMATION PROCESSING IN ANIMALS: Memory Mechanisms, Erlbaum, Hillsdale, NJ, 1981, p. 5] is described in terms of its assumed stimulus representation, network characteristics, and rules for learning and performance. It is shown how several Pavlovian conditioning phenomena can be accounted on the basis of the model's presumed stimulus representation. Challenges to the SOP model prompted the adoption of a componential stimulus representation in: AESOP [Contemporary Learning Theories: Pavlovian Conditioning and the Status of Traditional Learning Theory, Erlbaum, Hillsdale, NJ, 1989, p. 149], this was a dual representation of the unconditioned stimulus (US), and C-SOP [Contemporary Learning: Theory and Application, Erlbaum, Mahwah, NJ, 2001, p. 23], this was a multi-component representation of the conditioned stimulus (CS). The assumption of a componential CS representation, where large numbers of elements can be separately learned about, necessitated a modification of the learning rule. The modified, "constrained" rule was found useful to explain timing characteristics of Pavlovian conditioned responses, as well as data offered by Rescorla [J. Exp. Psychol. Anim. Behav. Process. 26 (2000) 428; Q. J. Exp. Psychol. 54B (2001) 53; J. Exp. Psychol. Anim. Behav. Process. 28 (2002) 163] showing that stimuli trained in compound do not share the same quantitative fate.

  4. Stimulus-specific oscillations in a retinal model.

    PubMed

    Kenyon, Garrett T; Travis, Bryan J; Theiler, James; George, John S; Stephens, Gregory J; Marshak, David W

    2004-09-01

    High-frequency oscillatory potentials (HFOPs) in the vertebrate retina are stimulus specific. The phases of HFOPs recorded at any given retinal location drift randomly over time, but regions activated by the same stimulus tend to remain phase locked with approximately zero lag, whereas regions activated by spatially separate stimuli are typically uncorrelated. Based on retinal anatomy, we previously postulated that HFOPs are mediated by feedback from a class of axon-bearing amacrine cells that receive excitation from neighboring ganglion cells-via gap junctions-and make inhibitory synapses back onto the surrounding ganglion cells. Using a computer model, we show here that such circuitry can account for the stimulus specificity of HFOPs in response to both high- and low-contrast features. Phase locking between pairs of model ganglion cells did not depend critically on their separation distance, but on whether the applied stimulus created a continuous path between them. The degree of phase locking between spatially separate stimuli was reduced by lateral inhibition, which created a buffer zone around strongly activated regions. Stimulating the inhibited region between spatially separate stimuli increased their degree of phase locking proportionately. Our results suggest several experimental strategies for testing the hypothesis that stimulus-specific HFOPs arise from axon-mediated feedback in the inner retina.

  5. Conditioned reinforcement as a function of duration of stimulus

    PubMed Central

    Dinsmoor, James A.; Mulvaney, Dallas E.; Jwaideh, Alice R.

    1981-01-01

    Pigeons were provided with three keys. Pecking the center key produced grain on a schedule that alternated at unpredictable times between a variable-interval component and extinction. On concurrent variable-interval schedules, pecking either side key produced a stimulus associated with the variable-interval component on the center key provided that said schedule was currently in effect. The independent variable was the length of time this stimulus remained on the keys. Pecking one side key produced the stimulus for 27 seconds, whereas the duration produced by pecking the other key varied for successive blocks of sessions. For the first four birds, the values tested were 3, 9, 27, and 81 seconds. For the second group, numbering three birds, the values tested were 1, 3, 9, and 27 seconds. The dependent variable was the proportion of total side key pecks that occurred on the variable key. For all birds, the function was positive in slope and negative in acceleration. This finding supports a formulation that ascribes the maintenance of observing responses in a normal setting to the fact that the subject exposes itself to the positive discriminative stimulus for a longer mean duration than it does to the negative stimulus. PMID:16812230

  6. Stimulus sensitive gel with radioisotope and methods of making

    DOEpatents

    Weller, Richard E.; Lind, Michael A.; Fisher, Darrell R.; Gutowska, Anna; Campbell, Allison A.

    2005-03-22

    The present invention is a thermally reversible stimulus-sensitive gel or gelling copolymer radioisotope carrier that is a linear random copolymer of an [meth-]acrylamide derivative and a hydrophilic comonomer, wherein the linear random copolymer is in the form of a plurality of linear chains having a plurality of molecular weights greater than or equal to a minimum gelling molecular weight cutoff. Addition of a biodegradable backbone and/or a therapeutic agent imparts further utility. The method of the present invention for making a thermally reversible stimulus-sensitive gelling copolymer radionuclcide carrier has the steps of: (a) mixing a stimulus-sensitive reversible gelling copolymer with an aqueous solvent as a stimulus-sensitive reversible gelling solution; and (b) mixing a radioisotope with said stimulus-sensitive reversible gelling solution as said radioisotope carrier. The gel is enhanced by either combining it with a biodegradable backbone and/or a therapeutic agent in a gelling solution made by mixing the copolymer with an aqueous solvent.

  7. Stimulus sensitive gel with radioisotope and methods of making

    DOEpatents

    Weller, Richard E [Selah, WA; Lind, Michael A [Kent, WA; Fisher, Darrell R [Richland, WA; Gutowska, Anna [Richland, WA; Campbell, Allison A [Kennewick, WA

    2001-10-02

    The present invention is a thermally reversible stimulus-sensitive gel or gelling copolymer radioisotope carrier that is a linear random copolymer of an [meth]acrylamide derivative and a hydrophilic comonomer, wherein the linear random copolymer is in the form of a plurality of linear chains having a plurality of molecular weights greater than or equal to a minimum gelling molecular weight cutoff. Addition of a biodegradable backbone and/or a therapeutic agent imparts further utility. The method of the present invention for making a thermally reversible stimulus-sensitive gelling copolymer radionuclcide carrier has the steps of: (a) mixing a stimulus-sensitive reversible gelling copolymer with an aqueous solvent as a stimulus-sensitive reversible gelling solution; and (b) mixing a radioisotope with said stimulus-sensitive reversible gelling solution as said radioisotope carrier. The gel is enhanced by either combining it with a biodegradable backbone and/or a therapeutic agent in a gelling solution made by mixing the copolymer with an aqueous solvent.

  8. Elicitation of natural language representations of uncertainty using computer technology

    SciTech Connect

    Tonn, B.; Goeltz, R.; Travis, C.; Tennessee Univ., Knoxville, TN )

    1989-01-01

    Knowledge elicitation is an important aspect of risk analysis. Knowledge about risks must be accurately elicited from experts for use in risk assessments. Knowledge and perceptions of risks must also be accurately elicited from the public in order to intelligently perform policy analysis and develop and implement programs. Oak Ridge National Laboratory is developing computer technology to effectively and efficiently elicit knowledge from experts and the public. This paper discusses software developed to elicit natural language representations of uncertainty. The software is written in Common Lisp and resides on VAX Computers System and Symbolics Lisp machines. The software has three goals, to determine preferences for using natural language terms for representing uncertainty; likelihood rankings of the terms; and how likelihood estimates are combined to form new terms. The first two goals relate to providing useful results for those interested in risk communication. The third relates to providing cognitive data to further our understanding of people's decision making under uncertainty. The software is used to elicit natural language terms used to express the likelihood of various agents causing cancer in humans and cancer resulting in various maladies, and the likelihood of everyday events. 6 refs., 4 figs., 4 tabs.

  9. Evaluation of Multiple-Stimulus Preference Assessment with Adults with Developmental Disabilities

    ERIC Educational Resources Information Center

    Davies, Gareth; Chand, Carly; Yu, C. T.; Martin, Toby L.; Martin, Garry L.

    2013-01-01

    We compared multiple-stimulus without replacement (MSWO) and paired-stimulus (PS) procedures to assess stimulus preferences of adults with developmental disabilities. Stimulus preference rankings for six food items obtained by the two procedures were positively correlated for all participants (M = 0.72, range 0.41 to 1). However, four participants…

  10. Effects of Multimodal Presentation and Stimulus Familiarity on Auditory and Visual Processing

    ERIC Educational Resources Information Center

    Robinson, Christopher W.; Sloutsky, Vladimir M.

    2010-01-01

    Two experiments examined the effects of multimodal presentation and stimulus familiarity on auditory and visual processing. In Experiment 1, 10-month-olds were habituated to either an auditory stimulus, a visual stimulus, or an auditory-visual multimodal stimulus. Processing time was assessed during the habituation phase, and discrimination of…

  11. Evidence that potential fish predators elicit the production of carapace vibrations by the American lobster.

    PubMed

    Ward, Daniel; Morison, Françoise; Morrissey, Elizabeth; Jenks, Kyle; Watson, Winsor H

    2011-08-01

    American lobsters (Homarus americanus) will on rare occasions produce sounds by vibrating their dorsal carapace. Although this behavior can be elicited in the laboratory by handling lobsters, the stimulus that triggers the production of sounds in the lobster's natural habitat is not known. We investigated the influence of two fish that are known to prey on lobsters, cod (Gadus morhua) and striped bass (Morone saxatilis), on the production of sounds by American lobsters. In addition, we examined the response of the same fish to the sounds the lobsters produced. Although solitary lobsters spontaneously produced sounds at a low rate of 1.2 ± 0.23 sound events per 30 min, the presence of a single cod or striped bass led to an increase in the rate of sound production (cod: 51.1 ± 13.1 events per 30 min; striped bass: 17.0 ± 7.0 events per 30 min). Most (74.6 ± 6.6%) of the 292 sound events recorded occurred when a fish came within 0.5 m of a lobster, but a fish did not have to come into contact with a lobster to elicit sounds. Immediately following the production of a sound by a lobster, fish turned and swam away significantly faster than when they encountered a lobster that did not make a sound. Moreover, after striped bass (but not cod) experienced a number of these sound events, they subsequently tended to avoid swimming close to the lobsters. These data, taken together, suggest that sound production by American lobsters may serve to deter potential fish predators. PMID:21753058

  12. Evidence that potential fish predators elicit the production of carapace vibrations by the American lobster.

    PubMed

    Ward, Daniel; Morison, Françoise; Morrissey, Elizabeth; Jenks, Kyle; Watson, Winsor H

    2011-08-01

    American lobsters (Homarus americanus) will on rare occasions produce sounds by vibrating their dorsal carapace. Although this behavior can be elicited in the laboratory by handling lobsters, the stimulus that triggers the production of sounds in the lobster's natural habitat is not known. We investigated the influence of two fish that are known to prey on lobsters, cod (Gadus morhua) and striped bass (Morone saxatilis), on the production of sounds by American lobsters. In addition, we examined the response of the same fish to the sounds the lobsters produced. Although solitary lobsters spontaneously produced sounds at a low rate of 1.2 ± 0.23 sound events per 30 min, the presence of a single cod or striped bass led to an increase in the rate of sound production (cod: 51.1 ± 13.1 events per 30 min; striped bass: 17.0 ± 7.0 events per 30 min). Most (74.6 ± 6.6%) of the 292 sound events recorded occurred when a fish came within 0.5 m of a lobster, but a fish did not have to come into contact with a lobster to elicit sounds. Immediately following the production of a sound by a lobster, fish turned and swam away significantly faster than when they encountered a lobster that did not make a sound. Moreover, after striped bass (but not cod) experienced a number of these sound events, they subsequently tended to avoid swimming close to the lobsters. These data, taken together, suggest that sound production by American lobsters may serve to deter potential fish predators.

  13. Objective visual field determination in forensic ophthalmology with an optimized 4-channel multifocal VEP perimetry system: a case report of a patient with retinitis pigmentosa.

    PubMed

    Kaltwasser, C; Horn, F K; Kremers, J; Juenemann, A; Bergua, A

    2011-10-01

    We present the case of a 59-year-old male patient with progressive vision impairment and consecutive visual field narrowing ("tunnel view") for 7 years and a known retinitis pigmentosa for 5 years. The remaining Goldmann perimetric visual field at time reported was less than 5°. A request for blindness-related social benefits was rejected because an ophthalmologic expert assessment suggested malingering. This prompted us to assess an objective determination of the visual field using multifocal VEPs. Objective visual field recordings were performed with a four-channel multifocal VEP-perimeter using 58 stimulus fields (pattern reversal dartboard stimulus configuration). The correlated signal data were processed using an off-line method. At each field, the recording from the channel with the maximal signal-to-noise ratio (SNR) was retained, thus resulting in an SNR optimized virtual recording. Analysis of VEP signals was performed for each single field and concentric rings and compared to an average response measured in five healthy subjects. Substantial VEP responses could be identified in three fields within the innermost ring (eccentricity, 1.7°) for both eyes, although SNR was generally low. More eccentric stimuli did not elicit reliable VEP responses. The mfVEP recording was correlated with perimetric visual field data. The current SNR optimization by using the channel with the largest SNR provides a good method to extract useful data from recordings and may be appropriate for the use in forensic ophthalmology.

  14. Contingency and stimulus change in chained schedules of reinforcement.

    PubMed

    Catania, A C; Yohalem, R; Silverman, P J

    1980-03-01

    Higher rates of pecking were maintained by pigeons in the middle component of three-component chained fixed-interval schedules than in that component of corresponding multiple schedules (two extinction components followed by a fixed-interval component). This rate difference did not occur in equivalent tandem and mixed schedules, in which a single stimulus was correlated with the three components. The higher rates in components of chained schedules demonstrate a reinforcing effect of the stimulus correlated with the next component; the acquired functions of this stimulus make the vocabulary of conditioned reinforcement appropriate. Problems in defining conditioned reinforcement arise not from difficulties in demonstrating reinforcing effects but from disagreements about which experimental operations allow such reinforcing effects to be called conditioned.

  15. The Development of Stimulus and Response Interference Control in Midchildhood

    PubMed Central

    2015-01-01

    Interference control, the ability to overcome distraction from irrelevant information, undergoes considerable improvement during childhood, yet the mechanisms driving these changes remain unclear. The present study investigated the relative influence of interference at the level of the stimulus or the response. Seven-, 10-, and 20-year-olds completed a flanker paradigm in which stimulus and response interference was experimentally manipulated. The influence of stimulus interference decreased from 7 to 10 years, whereas there was no difference in response interference across age groups. The findings demonstrate that a range of processes contribute to the development of interference control and may influence performance to a greater or lesser extent depending on the task requirements and the age of the child. PMID:26595353

  16. Multidimensional vector model of stimulus-response compatibility.

    PubMed

    Yamaguchi, Motonori; Proctor, Robert W

    2012-04-01

    The present study proposes and examines the multidimensional vector (MDV) model framework as a modeling schema for choice response times. MDV extends the Thurstonian model, as well as signal detection theory, to classification tasks by taking into account the influence of response properties on stimulus discrimination. It is capable of accounting for stimulus-response compatibility, which is known to be an influential task variable determining choice-reaction performance but has not been considered in previous mathematical modeling efforts. Specific MDV models were developed for 5 experiments using the Simon task, for which stimulus location is task irrelevant, to examine the validity of model assumptions and illustrate characteristic behaviors of model parameters. The MDV models accounted for the experimental data to a remarkable degree, demonstrating the adequacy of the framework as a general schema for modeling the latency of choice performance. Some modeling issues involved in the MDV model framework are discussed.

  17. Reinforcing and discriminative stimulus properties of music in goldfish.

    PubMed

    Shinozuka, Kazutaka; Ono, Haruka; Watanabe, Shigeru

    2013-10-01

    This paper investigated whether music has reinforcing and discriminative stimulus properties in goldfish. Experiment 1 examined the discriminative stimulus properties of music. The subjects were successfully trained to discriminate between two pieces of music--Toccata and Fugue in D minor (BWV 565) by J. S. Bach and The Rite of Spring by I. Stravinsky. Experiment 2 examined the reinforcing properties of sounds, including BWV 565 and The Rite of Spring. We developed an apparatus for measuring spontaneous sound preference in goldfish. Music or noise stimuli were presented depending on the subject's position in the aquarium, and the time spent in each area was measured. The results indicated that the goldfish did not show consistent preferences for music, although they showed significant avoidance of noise stimuli. These results suggest that music has discriminative but not reinforcing stimulus properties in goldfish. PMID:23796771

  18. Cognitive control in bilinguals: Advantages in Stimulus–Stimulus inhibition*

    PubMed Central

    BLUMENFELD, HENRIKE K.; MARIAN, VIORICA

    2014-01-01

    Bilinguals have been shown to outperform monolinguals at suppressing task-irrelevant information and on overall speed during cognitive control tasks. Here, monolinguals’ and bilinguals’ performance was compared on two nonlinguistic tasks: a Stroop task (with perceptual Stimulus–Stimulus conflict among stimulus features) and a Simon task (with Stimulus–Response conflict). Across two experiments testing bilinguals with different language profiles, bilinguals showed more efficient Stroop than Simon performance, relative to monolinguals, who showed fewer differences across the two tasks. Findings suggest that bilingualism may engage Stroop-type cognitive control mechanisms more than Simon-type mechanisms, likely due to increased Stimulus–Stimulus conflict during bilingual language processing. Findings are discussed in light of previous research on bilingual Stroop and Simon performance. PMID:25093009

  19. Implicit sequence learning is represented by stimulus-response rules.

    PubMed

    Schwarb, Hillary; Schumacher, Eric H

    2010-09-01

    For nearly two decades, researchers have investigated spatial sequence learning in an attempt to identify what specifically is learned during sequential tasks (e.g., stimulus order, response order, etc.). Despite extensive research, controversy remains concerning the information-processing locus of this learning effect. There are three main theories concerning the nature of spatial sequence learning, corresponding to the perceptual, motor, or response selection (i.e., central mechanisms underlying the association between stimulus and response pairs) processes required for successful task performance. The present data investigate this controversy and support the theory that stimulus-response (S-R) rules are critical for sequence learning. The results from two experiments demonstrate that sequence learning is disrupted only when the S-R rules for the task are altered. When the S-R rules remain constant or involve only a minor transformation, significant sequence learning occurs. These data implicate spatial response selection as a likely mechanism mediating spatial sequential learning.

  20. Transduction of the gravity stimulus in the root statocyte.

    PubMed

    Perbal, G; Driss-Ecole, D

    1994-01-01

    The amyloplasts of root statocytes are considered to be the perceptors of gravity. However, their displacement and the starch they contain are not required for gravisensing. The mechanism of the transduction of gravistimulus remains therefore controversial. It is well known that the amplitude of the stimulus is dependent upon the intensity of the acceleration and the inclination of the root with respect to gravity. This strongly supports the hypothesis that the stimulus results in a mechanical effect (pressure or tension) on a cellular structure. Three cellular components are proposed as possible candidates for the role of transducer: the actin filaments, the endoplasmic reticulum and the plasma membrane with its ion channels. Recent results obtained in the frame of the IML 1 Mission of Spacelab show that the endoplasmic reticulum should rather be responsible for the termination of the stimulus. The contacts of amyloplasts with the distal ER could therefore be involved in the regulation of root growth. PMID:11537906

  1. Adaptation to stimulus contrast and correlations during natural visual stimulation

    PubMed Central

    Lesica, Nicholas A.; Jin, Jianzhong; Weng, Chong; Yeh, Chun-I; Butts, Daniel A.; Stanley, Garrett B.; Alonso, Jose-Manuel

    2008-01-01

    Summary In this study, we characterize the adaptation of neurons in the cat lateral geniculate nucleus to changes in stimulus contrast and correlations. By comparing responses to high and low contrast natural scene movie and white noise stimuli, we show that an increase in contrast or correlations results in receptive fields with faster temporal dynamics and stronger antagonistic surrounds, as well as decreases in gain and selectivity. We also observe contrast- and correlation-induced changes in the reliability and sparseness of neural responses. We find that reliability is determined primarily by processing in the receptive field (the effective contrast of the stimulus), while sparseness is determined by the interactions between several functional properties. These results reveal a number of novel adaptive phenomena and suggest that adaptation to stimulus contrast and correlations may play an important role in visual coding in a dynamic natural environment. PMID:17678859

  2. Cognitive versus stimulus-response theories of learning.

    PubMed

    Holland, Peter C

    2008-08-01

    In his 1948 address to the Division of Theoretical-Experimental Psychology of the American Psychological Association, Kenneth W. Spence discussed six distinctions between cognitive and stimulus-response (S-R) theories of learning. In this article, I first review these six distinctions and then focus on two of them in the context of my own research. This research concerns the specification of stimulus-stimulus associations in associative learning and the characterization of the neural systems underlying those associations. In the course of describing Spence's views and my research, I hope to communicate some of the richness of Spence's S-R psychology and its currency within modern scientific analyses of behavior.

  3. Operant discrimination of an interoceptive stimulus in rhesus monkeys1

    PubMed Central

    Slucki, Henry; Adam, Gyorgi; Porter, Robert W.

    1965-01-01

    Five rhesus macaques monkeys surgically prepared with Thiry small intestinal (jejunum) loops and implanted brain electrodes were restrained in primate chairs and kept on 23-hr deprivation-feeding cycle. After being trained to press a lever for sugar pills on an FR 25 schedule of reinforcement, a discrimination training procedure was established. Lever presses were reinforced during the SD—a non-aversive mechanical stimulus applied to the internal walls of the Thiry loop by rhythmic inflation-deflation of a small latex balloon by air at the rate of one cycle per sec at 100 mm Hg pressure. The SΔ was the absence of the visceral stimulation. The monkeys successfully discriminated between presence and absence of the internal stimulus. A discrimination reversal was attempted and completed on one monkey. The results clearly show operant discrimination based on an interoceptive stimulus. Cortical and subcortical EEG records reflected the onset but not termination of the visceral stimulation. PMID:4954822

  4. Naming, the formation of stimulus classes, and applied behavior analysis.

    PubMed Central

    Stromer, R; Mackay, H A; Remington, B

    1996-01-01

    The methods used in Sidman's original studies on equivalence classes provide a framework for analyzing functional verbal behavior. Sidman and others have shown how teaching receptive, name-referent matching may produce rudimentary oral reading and word comprehension skills. Eikeseth and Smith (1992) have extended these findings by showing that children with autism may acquire equivalence classes after learning to supply a common oral name to each stimulus in a potential class. A stimulus class analysis suggests ways to examine (a) the problem of programming generalization from teaching situations to other environments, (b) the expansion of the repertoires that occur in those settings, and (c) the use of naming to facilitate these forms of generalization. Such research will help to clarify and extend Horne and Lowe's recent (1996) account of the role of verbal behavior in the formation of stimulus classes. PMID:8810064

  5. [Discriminative stimulus properties of ephedra herb (Ephedra sinica) in rats].

    PubMed

    Furuya, I; Watanabe, S

    1993-02-01

    The stimulus properties of ephedra herb (drug of Chinese medicine) were demonstrated in rats trained to discriminate between 2.5 ml/kg extract of ephedra herb and same volume of distilled water (p.o.). On the discrimination training, animals were shaped on an FR20 schedule to respond to one of two levers for food reinforcement when they were administrated ephedra herb extract, and to respond to the other lever when they were treated with distilled water. Cumulative dosing tests for the discriminative stimulus properties consisted of two to five trials of FR20 schedule; responses for both levers were reinforced. d-Methamphetamine 1.43 mg/kg p.o. indicated complete generalization to the ephedra herb. Nicotine and caffeine indicated modest generalization, but some animals generalized completely. These results suggest that the ephedra herb has d-methamphetamine-like, but unique discriminative stimulus properties.

  6. Reinforcing and discriminative stimulus properties of music in goldfish.

    PubMed

    Shinozuka, Kazutaka; Ono, Haruka; Watanabe, Shigeru

    2013-10-01

    This paper investigated whether music has reinforcing and discriminative stimulus properties in goldfish. Experiment 1 examined the discriminative stimulus properties of music. The subjects were successfully trained to discriminate between two pieces of music--Toccata and Fugue in D minor (BWV 565) by J. S. Bach and The Rite of Spring by I. Stravinsky. Experiment 2 examined the reinforcing properties of sounds, including BWV 565 and The Rite of Spring. We developed an apparatus for measuring spontaneous sound preference in goldfish. Music or noise stimuli were presented depending on the subject's position in the aquarium, and the time spent in each area was measured. The results indicated that the goldfish did not show consistent preferences for music, although they showed significant avoidance of noise stimuli. These results suggest that music has discriminative but not reinforcing stimulus properties in goldfish.

  7. Human perceptual decision making: disentangling task onset and stimulus onset.

    PubMed

    Cardoso-Leite, Pedro; Waszak, Florian; Lepsien, Jöran

    2014-07-01

    The left dorsolateral prefrontal cortex (ldlPFC) has been highlighted as a key actor in human perceptual decision-making (PDM): It is theorized to support decision-formation independently of stimulus type or motor response. PDM studies however generally confound stimulus onset and task onset: when the to-be-recognized stimulus is presented, subjects know that a stimulus is shown and can set up processing resources-even when they do not know which stimulus is shown. We hypothesized that the ldlPFC might be involved in task preparation rather than decision-formation. To test this, we asked participants to report whether sequences of noisy images contained a face or a house within an experimental design that decorrelates stimulus and task onset. Decision-related processes should yield a sustained response during the task, whereas preparation-related areas should yield transient responses at its beginning. The results show that the brain activation pattern at task onset is strikingly similar to that observed in previous PDM studies. In particular, they contradict the idea that ldlPFC forms an abstract decision and suggest instead that its activation reflects preparation for the upcoming task. We further investigated the role of the fusiform face areas and parahippocampal place areas which are thought to be face and house detectors, respectively, that feed their signals to higher level decision areas. The response patterns within these areas suggest that this interpretation is unlikely and that the decisions about the presence of a face or a house in a noisy image might instead already be computed within these areas without requiring higher-order areas.

  8. Pre-stimulus thalamic theta power predicts human memory formation.

    PubMed

    Sweeney-Reed, Catherine M; Zaehle, Tino; Voges, Jürgen; Schmitt, Friedhelm C; Buentjen, Lars; Kopitzki, Klaus; Richardson-Klavehn, Alan; Hinrichs, Hermann; Heinze, Hans-Jochen; Knight, Robert T; Rugg, Michael D

    2016-09-01

    Pre-stimulus theta (4-8Hz) power in the hippocampus and neocortex predicts whether a memory for a subsequent event will be formed. Anatomical studies reveal thalamus-hippocampal connectivity, and lesion, neuroimaging, and electrophysiological studies show that memory processing involves the dorsomedial (DMTN) and anterior thalamic nuclei (ATN). The small size and deep location of these nuclei have limited real-time study of their activity, however, and it is unknown whether pre-stimulus theta power predictive of successful memory formation is also found in these subcortical structures. We recorded human electrophysiological data from the DMTN and ATN of 7 patients receiving deep brain stimulation for refractory epilepsy. We found that greater pre-stimulus theta power in the right DMTN was associated with successful memory encoding, predicting both behavioral outcome and post-stimulus correlates of successful memory formation. In particular, significant correlations were observed between right DMTN theta power and both frontal theta and right ATN gamma (32-50Hz) phase alignment, and frontal-ATN theta-gamma cross-frequency coupling. We draw the following primary conclusions. Our results provide direct electrophysiological evidence in humans of a role for the DMTN as well as the ATN in memory formation. Furthermore, prediction of subsequent memory performance by pre-stimulus thalamic oscillations provides evidence that post-stimulus differences in thalamic activity that index successful and unsuccessful encoding reflect brain processes specifically underpinning memory formation. Finally, the findings broaden the understanding of brain states that facilitate memory encoding to include subcortical as well as cortical structures. PMID:27208861

  9. Calibration of ipsilateral stimulus transducer for acoustic reflex measurements.

    PubMed

    Olsen, S; Osterhammel, P A; Rasmussen, A N; Nielsen, L H

    1995-01-01

    Pure-tone Reference Equivalent Threshold Sound Pressure Level (RETSPL) of the ipsilateral stimulus receiver for acoustic reflex measurements on Madsen Electronics type Zodiac 901 impedance audiometer is provided. The results, obtained from 20 normal-hearing subjects, are achieved by comparing hearing threshold levels measured using a TDH 39 telephone (calibrated to ISO 389) with thresholds recorded using the ipsilateral stimulus insert phone. The calibration is referenced to an IEC-711 ear simulator and comprises the following frequencies: 125, 250, 500, 750, 1000, 1500, 2000, 3000, 4000, 6000, 8000 Hz.

  10. Simple 3-D stimulus for motion parallax and its simulation.

    PubMed

    Ono, Hiroshi; Chornenkyy, Yevgen; D'Amour, Sarah

    2013-01-01

    Simulation of a given stimulus situation should produce the same perception as the original. Rogers et al (2009 Perception 38 907-911) simulated Wheeler's (1982, PhD thesis, Rutgers University, NJ) motion parallax stimulus and obtained quite different perceptions. Wheeler's observers were unable to reliably report the correct direction of depth, whereas Rogers's were. With three experiments we explored the possible reasons for the discrepancy. Our results suggest that Rogers was able to see depth from the simulation partly due to his experience seeing depth with random dot surfaces. PMID:23964382

  11. Evaluation of an enhanced stimulus-stimulus pairing procedure to increase early vocalizations of children with autism.

    PubMed

    Esch, Barbara E; Carr, James E; Grow, Laura L

    2009-01-01

    Evidence to support stimulus-stimulus pairing (SSP) in speech acquisition is less than robust, calling into question the ability of SSP to reliably establish automatically reinforcing properties of speech and limiting the procedure's clinical utility for increasing vocalizations. We evaluated the effects of a modified SSP procedure on low-frequency within-session vocalizations that were further strengthened through programmed reinforcement. Procedural modifications (e.g., interspersed paired and unpaired trials) were designed to increase stimulus salience during SSP. All 3 participants, preschoolers with autism, showed differential increases of target over nontarget vocal responses during SSP. Results suggested an automatic reinforcement effect of SSP, although alternative interpretations are discussed, and suggestions are made for future research to determine the utility of SSP as a clinical intervention for speech-delayed children. PMID:19949511

  12. Evaluation of an enhanced stimulus-stimulus pairing procedure to increase early vocalizations of children with autism.

    PubMed

    Esch, Barbara E; Carr, James E; Grow, Laura L

    2009-01-01

    Evidence to support stimulus-stimulus pairing (SSP) in speech acquisition is less than robust, calling into question the ability of SSP to reliably establish automatically reinforcing properties of speech and limiting the procedure's clinical utility for increasing vocalizations. We evaluated the effects of a modified SSP procedure on low-frequency within-session vocalizations that were further strengthened through programmed reinforcement. Procedural modifications (e.g., interspersed paired and unpaired trials) were designed to increase stimulus salience during SSP. All 3 participants, preschoolers with autism, showed differential increases of target over nontarget vocal responses during SSP. Results suggested an automatic reinforcement effect of SSP, although alternative interpretations are discussed, and suggestions are made for future research to determine the utility of SSP as a clinical intervention for speech-delayed children.

  13. Pre-stimulus alpha and post-stimulus N2 foreshadow imminent errors in a single task.

    PubMed

    Shou, Guofa; Dasari, Deepika; Ding, Lei

    2015-10-01

    Performance errors have been attributed to distinct neural mechanisms in different tasks. Two temporally and physiologically dissociable neural patterns prior to errors, i.e., pre-stimulus alpha (8-13 Hz) power indicative of sustained attention and post-stimulus N2 amplitude indicative of cognitive control, have been widely (but independently) reported in many studies. However, it is still largely unknown whether these two neural mechanisms for error commission exist in a single task at the same time and, if so, whether they can be probed simultaneously and how they lead to response accuracy (collectively or separately). To this end, we measured high-density electroencephalography (EEG) signals in a color-word matching Stroop task. We quantified both patterns on EEG data from individual stimulus condition (congruent or incongruent), as well as on pooled data from both conditions. Enhanced pre-stimulus alpha power for errors was identified over the parieto-occipital area in the congruent condition and the pooled data. Reduced post-stimulus N2 amplitude was only revealed in the incongruent condition. More importantly, for the first time, a balanced interaction between these two EEG patterns was revealed in correct trials, but not in error trials. These findings suggest that errors in one task could occur due to distinct neural mechanisms, e.g., poor sustained attention, poor cognitive control, or missed balance between these two. The present results further suggest that the detection of neural patterns related to different neural mechanisms could be complicated by other modulation factors, such as stimulus condition. Therefore, more than one neural marker should be simultaneously monitored to effectively predict imminent errors. PMID:26362494

  14. Protoplasmic streaming of an internodal cell of Nitella flexilis; its correlation with electric stimulus.

    PubMed

    KISHIMOTO, U; AKABORI, H

    1959-07-20

    The sudden cessation or sudden decrease in velocity of the protoplasmic streaming of Nitella flexilis is observed whenever an action potential is elicited. The action potential can be generated by an electric stimulus after its refractory period, whether the flow is at a complete standstill or on the way to recovery. The membrane potential is generally decreased more or less when the rate of flow is decreased on application of salts or other agents. There is, however, no parallelism between these two. The membrane potential decreases proportionally with applied voltage of subthreshold intensity, while the rate of flow does not change appreciably. Only on application of a superthreshold voltage does the flow stop suddenly. In one case the rate of flow decreased to half without appreciable decrease in membrane potential. In another case it continued flowing at about one-half rate, although the membrane potential was almost zero. The Q(10) of the rate of flow is about 2, while it is 1.1 to 1.5 for the membrane potential. The sudden cessation of the protoplasmic streaming is supposed to be caused by the temporary formation of certain interlinkages among contractile protein networks in the endoplasm during excitation at the cathodal half of Nitella.

  15. Effects of Posture and Stimulus Spectral Composition on Peripheral Physiological Responses to Loud Sounds

    PubMed Central

    Koch, Jennifer; Flemming, Jan; Zeffiro, Thomas; Rufer, Michael; Orr, Scott P.; Mueller-Pfeiffer, Christoph

    2016-01-01

    In the “loud-tone” procedure, a series of brief, loud, pure-tone stimuli are presented in a task-free situation. It is an established paradigm for measuring autonomic sensitization in posttraumatic stress disorder (PTSD). Successful use of this procedure during fMRI requires elicitation of brain responses that have sufficient signal-noise ratios when recorded in a supine, rather than sitting, position. We investigated the modulating effects of posture and stimulus spectral composition on peripheral psychophysiological responses to loud sounds. Healthy subjects (N = 24) weekly engaged in a loud-tone-like procedure that presented 500 msec, 95 dB sound pressure level, pure-tone or white-noise stimuli, either while sitting or supine and while peripheral physiological responses were recorded. Heart rate, skin conductance, and eye blink electromyographic responses were larger to white-noise than pure-tone stimuli (p’s < 0.001, generalized eta squared 0.073–0.076). Psychophysiological responses to the stimuli were similar in the sitting and supine position (p’s ≥ 0.082). Presenting white noise, rather than pure-tone, stimuli may improve the detection sensitivity of the neural concomitants of heightened autonomic responses by generating larger responses. Recording in the supine position appears to have little or no impact on psychophysiological response magnitudes to the auditory stimuli. PMID:27583659

  16. Effects of Posture and Stimulus Spectral Composition on Peripheral Physiological Responses to Loud Sounds.

    PubMed

    Koch, Jennifer; Flemming, Jan; Zeffiro, Thomas; Rufer, Michael; Orr, Scott P; Mueller-Pfeiffer, Christoph

    2016-01-01

    In the "loud-tone" procedure, a series of brief, loud, pure-tone stimuli are presented in a task-free situation. It is an established paradigm for measuring autonomic sensitization in posttraumatic stress disorder (PTSD). Successful use of this procedure during fMRI requires elicitation of brain responses that have sufficient signal-noise ratios when recorded in a supine, rather than sitting, position. We investigated the modulating effects of posture and stimulus spectral composition on peripheral psychophysiological responses to loud sounds. Healthy subjects (N = 24) weekly engaged in a loud-tone-like procedure that presented 500 msec, 95 dB sound pressure level, pure-tone or white-noise stimuli, either while sitting or supine and while peripheral physiological responses were recorded. Heart rate, skin conductance, and eye blink electromyographic responses were larger to white-noise than pure-tone stimuli (p's < 0.001, generalized eta squared 0.073-0.076). Psychophysiological responses to the stimuli were similar in the sitting and supine position (p's ≥ 0.082). Presenting white noise, rather than pure-tone, stimuli may improve the detection sensitivity of the neural concomitants of heightened autonomic responses by generating larger responses. Recording in the supine position appears to have little or no impact on psychophysiological response magnitudes to the auditory stimuli. PMID:27583659

  17. Neurotrophins: peripherally and centrally acting modulators of tactile stimulus-induced inflammatory pain hypersensitivity.

    PubMed

    Mannion, R J; Costigan, M; Decosterd, I; Amaya, F; Ma, Q P; Holstege, J C; Ji, R R; Acheson, A; Lindsay, R M; Wilkinson, G A; Woolf, C J

    1999-08-01

    Brain-derived neurotrophic factor (BDNF) is expressed in nociceptive sensory neurons and transported anterogradely to the dorsal horn of the spinal cord where it is located in dense core vesicles in C-fiber terminals. Peripheral inflammation substantially up-regulates BDNF mRNA and protein in the dorsal root ganglion (DRG) in a nerve growth factor-dependent fashion and results in novel expression of BDNF by DRG neurons with myelinated axons. C-fiber electrical activity also increases BDNF expression in the DRG, and both inflammation and activity increase full-length TrkB receptor levels in the dorsal horn. Sequestration of endogenous BDNF/neurotrophin 4 by intraspinal TrkB-Fc fusion protein administration does not, in noninflamed animals, change basal pain sensitivity nor the mechanical hypersensitivity induced by peripheral capsaicin administration, a measure of C fiber-mediated central sensitization. TrkB-Fc administration also does not modify basal inflammatory pain hypersensitivity, but does block the progressive hypersensitivity elicited by low-intensity tactile stimulation of inflamed tissue. BDNF, by virtue of its nerve growth factor regulation in sensory neurons including novel expression in A fibers, has a role as a central modulator of tactile stimulus-induced inflammatory pain hypersensitivity.

  18. Haze, clouds and limited sky visibility: polarotactic orientation of crickets under difficult stimulus conditions.

    PubMed

    Henze, Miriam J; Labhart, Thomas

    2007-09-01

    Field crickets (Gryllus campestris L.) are able to detect the orientation of the electric vector (e-vector) of linearly polarized light. They presumably use this sense to exploit the celestial polarization pattern for course control or navigation. Polarization vision in crickets can be tested by eliciting a spontaneous polarotactic response. Previously, wide and 100% polarized stimuli were employed to induce this behavior. However, field crickets live on meadows where the observation of the sky is strongly limited by surrounding vegetation. Moreover, degrees of polarization (d) in the natural sky are much lower than 100%. We have therefore investigated thresholds for the behavioral response to polarized light under conditions mimicking those experienced by the insects in the field. We show that crickets are able to rely on polarized stimuli of just 1 degrees diameter. We also provide evidence that they exploit polarization down to an (average) polarization level of less than 7%, irrespective of whether the stimulus is homogeneous, such as under haze, or patched, such as a sky spotted by clouds. Our data demonstrate that crickets can rely on skylight polarization even under unfavorable celestial conditions, emphasizing the significance of polarized skylight orientation for insects.

  19. Quantitative analysis of naloxone antagonism of the discriminative stimulus properties of morphine in the pigeon.

    PubMed

    Wessinger, W D; McMillan, D E

    1986-07-01

    Pigeons were trained to discriminate morphine (5.0 mg/kg) from saline under a second-order fixed ratio 10 (fixed-ratio 5) color-tracking schedule for food reinforcement. After reliable stimulus control was established, cumulative graded doses of morphine (0.3-30.0 mg/kg) were tested and resulted in dose-dependent increases in morphine-appropriate key pecking and decreases in response rate. Cumulative doses of naloxone (0.1-10.0 mg/kg) or consecutive injections of saline did not elicit morphine-appropriate responding or affect response rate. Pre-treatment with naloxone (0.1-1.0 mg/kg) before determination of cumulative dose-effect curves for morphine caused the morphine generalization curves to be shifted, in a parallel manner, rightward. Dose-ratio analysis of naloxone antagonism of morphine generalization, using a Schild plot with the slope constrained to -1, gave an apparent pA2 value (95% confidence limits) of 6.53 (6.18-6.89).

  20. Topographic Distribution of Stimulus-Specific Adaptation across Auditory Cortical Fields in the Anesthetized Rat

    PubMed Central

    Nieto-Diego, Javier; Malmierca, Manuel S.

    2016-01-01

    Stimulus-specific adaptation (SSA) in single neurons of the auditory cortex was suggested to be a potential neural correlate of the mismatch negativity (MMN), a widely studied component of the auditory event-related potentials (ERP) that is elicited by changes in the auditory environment. However, several aspects on this SSA/MMN relation remain unresolved. SSA occurs in the primary auditory cortex (A1), but detailed studies on SSA beyond A1 are lacking. To study the topographic organization of SSA, we mapped the whole rat auditory cortex with multiunit activity recordings, using an oddball paradigm. We demonstrate that SSA occurs outside A1 and differs between primary and nonprimary cortical fields. In particular, SSA is much stronger and develops faster in the nonprimary than in the primary fields, paralleling the organization of subcortical SSA. Importantly, strong SSA is present in the nonprimary auditory cortex within the latency range of the MMN in the rat and correlates with an MMN-like difference wave in the simultaneously recorded local field potentials (LFP). We present new and strong evidence linking SSA at the cellular level to the MMN, a central tool in cognitive and clinical neuroscience. PMID:26950883

  1. The discriminative stimulus properties of ethanol and acute ethanol withdrawal states in rats.

    PubMed

    Gauvin, D V; Harland, R D; Criado, J R; Michaelis, R C; Holloway, F A

    1989-10-01

    Twelve male Sprague-Dawley rats were trained in a standard two-choice Drug 1-Drug 2 discrimination task utilizing 3.0 mg/kg chlordiazepoxide (CDP, an anxiolytic drug) and 20 mg/kg pentylenetetrazol (PTZ, an anxiogenic drug) as discriminative stimuli under a VR 5-15 schedule of food reinforcement. Saline tests conducted at specific time points after acute high doses of ethanol (3.0 and 4.0 g/kg) indicated a delayed rebound effect, evidenced by a shift to PTZ-appropriate responding. Insofar as such a shift in lever selection indexes a delayed anxiety-like state, this acute 'withdrawal' reaction can be said to induce an affective state similar to that seen with chronic ethanol withdrawal states. Ethanol generalization tests: (1) resulted in a dose- and time-dependent biphasic generalization to CDP, (2) failed to block the PTZ stimulus and (3) failed to block the time- and dose-dependent elicitation of an ethanol-rebound effect. These data suggest that ethanol's anxiolytic effects are tenuous. PMID:2791886

  2. Metabotropic glutamate receptor subtype 5: molecular pharmacology, allosteric modulation and stimulus bias.

    PubMed

    Sengmany, K; Gregory, K J

    2016-10-01

    The metabotropic glutamate receptor subtype 5 (mGlu5 ) is a family C GPCR that has been implicated in various neuronal processes and, consequently, in several CNS disorders. Over the past few decades, GPCR-based drug discovery, including that for mGlu5 receptors, has turned considerable attention to targeting allosteric binding sites. Modulation of endogenous agonists by allosteric ligands offers the advantages of spatial and temporal fine-tuning of receptor activity, increased selectivity and reduced adverse effects with the potential to elicit improved clinical outcomes. Further, with greater appreciation of the multifaceted nature of the transduction of mGlu5 receptor signalling, it is increasingly apparent that drug discovery must take into consideration unique receptor conformations and the potential for stimulus-bias. This novel paradigm proposes that different ligands may differentially modulate distinct signalling pathways arising from the same receptor. We review our current understanding of the complexities of mGlu5 receptor signalling and regulation, and how these relate to allosteric ligands. Ultimately, a deeper appreciation of these relationships will provide the foundation for targeted drug design of compounds with increased selectivity, not only for the desired receptor but also for the desired signalling outcome from the receptor. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.

  3. Interoceptive fear conditioning and panic disorder: the role of conditioned stimulus-unconditioned stimulus predictability.

    PubMed

    Acheson, Dean T; Forsyth, John P; Moses, Erica

    2012-03-01

    Interoceptive fear conditioning is at the core of contemporary behavioral accounts of panic disorder. Yet, to date only one study has attempted to evaluate interoceptive fear conditioning in humans (see Acheson, Forsyth, Prenoveau, & Bouton, 2007). That study used brief (physiologically inert) and longer-duration (panicogenic) inhalations of 20% CO(2)-enriched air as an interoceptive conditioned (CS) and unconditioned (US) stimulus and evaluated fear learning in three conditions: CS only, CS-US paired, and CS-US unpaired. Results showed fear conditioning in the paired condition, and fearful responding and resistance to extinction in an unpaired condition. The authors speculated that such effects may be due to difficulty discriminating between the CS and the US. The aims of the present study are to (a) replicate and expand this line of work using an improved methodology, and (b) clarify the role of CS-US discrimination difficulties in either potentiating or depotentiating fear learning. Healthy participants (N=104) were randomly assigned to one of four conditions: (a) CS only, (b) contingent CS-US pairings, (c) unpaired CS and US presentations, or (d) an unpaired "discrimination" contingency, which included an exteroceptive discrimination cue concurrently with CS onset. Electrodermal and self-report ratings served as indices of conditioned responding. Consistent with expectation, the paired contingency and unpaired contingencies yielded elevated fearful responding to the CS alone. Moreover, adding a discrimination cue to the unpaired contingency effectively attenuated fearful responding. Overall, findings are consistent with modern learning theory accounts of panic and highlight the role of interoceptive conditioning and unpredictability in the etiology of panic disorder.

  4. Interoceptive fear conditioning and panic disorder: the role of conditioned stimulus-unconditioned stimulus predictability.

    PubMed

    Acheson, Dean T; Forsyth, John P; Moses, Erica

    2012-03-01

    Interoceptive fear conditioning is at the core of contemporary behavioral accounts of panic disorder. Yet, to date only one study has attempted to evaluate interoceptive fear conditioning in humans (see Acheson, Forsyth, Prenoveau, & Bouton, 2007). That study used brief (physiologically inert) and longer-duration (panicogenic) inhalations of 20% CO(2)-enriched air as an interoceptive conditioned (CS) and unconditioned (US) stimulus and evaluated fear learning in three conditions: CS only, CS-US paired, and CS-US unpaired. Results showed fear conditioning in the paired condition, and fearful responding and resistance to extinction in an unpaired condition. The authors speculated that such effects may be due to difficulty discriminating between the CS and the US. The aims of the present study are to (a) replicate and expand this line of work using an improved methodology, and (b) clarify the role of CS-US discrimination difficulties in either potentiating or depotentiating fear learning. Healthy participants (N=104) were randomly assigned to one of four conditions: (a) CS only, (b) contingent CS-US pairings, (c) unpaired CS and US presentations, or (d) an unpaired "discrimination" contingency, which included an exteroceptive discrimination cue concurrently with CS onset. Electrodermal and self-report ratings served as indices of conditioned responding. Consistent with expectation, the paired contingency and unpaired contingencies yielded elevated fearful responding to the CS alone. Moreover, adding a discrimination cue to the unpaired contingency effectively attenuated fearful responding. Overall, findings are consistent with modern learning theory accounts of panic and highlight the role of interoceptive conditioning and unpredictability in the etiology of panic disorder. PMID:22304889

  5. Where is the ball? Behavioral and neural responses elicited by a magic trick.

    PubMed

    Caffaratti, Hugo; Navajas, Joaquin; Rey, Hernan G; Quian Quiroga, Rodrigo

    2016-09-01

    We present results from two experiments, in which subjects watched continuous videos of a professional magician repeatedly performing a maneuver in which a ball could "magically" appear under a cup. In all cases, subjects were asked to predict whether the ball would appear under the cup or not, while scalp EEG recordings were performed. Both experiments elicited strong and consistent behavioral and neural responses. In the first experiment, we used two blocks of videos with different probabilities of the ball appearing in the cup and found that, first, based on the behavioral responses, the subjects could track this probability change; and second, the different probabilities modulated the neural responses. In the second experiment, we introduced a control condition in which the magician performed the maneuver under the table, out of subjects' view. Comparing the two conditions (i.e., performing the maneuver within or out of the subjects' view), we found that, first, the magic trick dramatically biased the subjects' behavioral responses; and second, the two conditions led to differential neural responses, in spite of the fact that the stimulus triggering the evoked responses (seeing the ball in the cup) was exactly the same. Altogether, our results show how new insights into sensory and cognitive processing can be obtained using adapted magic tricks. Moreover, the approach of analyzing responses to continuous video presentations offers a more ecological setting compared to classic evoked potential paradigms, which are typically based on presenting static images flashed at the center of the screen. PMID:27356507

  6. Where is the ball? Behavioral and neural responses elicited by a magic trick.

    PubMed

    Caffaratti, Hugo; Navajas, Joaquin; Rey, Hernan G; Quian Quiroga, Rodrigo

    2016-09-01

    We present results from two experiments, in which subjects watched continuous videos of a professional magician repeatedly performing a maneuver in which a ball could "magically" appear under a cup. In all cases, subjects were asked to predict whether the ball would appear under the cup or not, while scalp EEG recordings were performed. Both experiments elicited strong and consistent behavioral and neural responses. In the first experiment, we used two blocks of videos with different probabilities of the ball appearing in the cup and found that, first, based on the behavioral responses, the subjects could track this probability change; and second, the different probabilities modulated the neural responses. In the second experiment, we introduced a control condition in which the magician performed the maneuver under the table, out of subjects' view. Comparing the two conditions (i.e., performing the maneuver within or out of the subjects' view), we found that, first, the magic trick dramatically biased the subjects' behavioral responses; and second, the two conditions led to differential neural responses, in spite of the fact that the stimulus triggering the evoked responses (seeing the ball in the cup) was exactly the same. Altogether, our results show how new insights into sensory and cognitive processing can be obtained using adapted magic tricks. Moreover, the approach of analyzing responses to continuous video presentations offers a more ecological setting compared to classic evoked potential paradigms, which are typically based on presenting static images flashed at the center of the screen.

  7. Event Related Potential Analysis of Stimulus Over-Selectivity

    ERIC Educational Resources Information Center

    Reed, Phil; Savile, Amy; Truzoli, Roberto

    2012-01-01

    Stimulus over-selectivity is a phenomenon often displayed by individuals with many forms of developmental and intellectual disabilities, and also by individuals lacking such disabilities who are under cognitive strain. It occurs when only one of potentially many aspects of the environment controls behavior. Adult participants were trained and…

  8. Stimulus Similarity as a Determinant of Pavlovian Conditioning

    ERIC Educational Resources Information Center

    Rescorla, Robert A.; Furrow, David R.

    1977-01-01

    Three experiments carried out second-order Pavlovian conditioning using either similar or dissimilar first-and second-order stimuli. All three experiments were designed to identify the effects of similarity upon conditioning as distinct from its effects upon sensitization or stimulus generalization. (Editor/RK)

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

    ERIC Educational Resources Information Center

    Leung, Jin-Pang

    1988-01-01

    The study assessed transfer of visual training for myopia using two different training stimuli and a single subject A-B-C-A design with a male student volunteer. A procedure including stimulus fading and reinforcement (positive verbal feedback) was used to effectively improve performance on both behavioral acuity tests during the training phases…

  10. Salivary conditioning with antennal gustatory unconditioned stimulus in an insect.

    PubMed

    Watanabe, Hidehiro; Sato, Chihiro; Kuramochi, Tomokazu; Nishino, Hiroshi; Mizunami, Makoto

    2008-07-01

    Classical conditioning of olfactory conditioning stimulus (CS) with gustatory unconditioned stimulus (US) in insects has been used as a pertinent model for elucidation of neural mechanisms underlying learning and memory. However, a conditioning system in which stable intracellular recordings from brain neurons are feasibly obtained while monitoring the conditioning effect has remained to be established. Recently, we found classical conditioning of salivation in cockroaches Periplaneta americana, in which an odor was associated with sucrose solution applied to the mouth, and this conditioning could be monitored by activities of salivary neurons. Application of gustatory US to the mouth, however, leads to feeding movement accompanying a movement of the brain that prevents stable recordings from brain neurons. Here we investigated whether a gustatory stimulus presented to an antenna could serve as an effective US for producing salivary conditioning. Presentation of sucrose or sodium chloride solution to an antenna induced salivation and also increased activities of salivary neurons. A single pairing trial of an odor with antennal presentation of sucrose or sodium chloride solution produced conditioning of salivation or of activities of salivary neurons. Five pairing trials led to a conditioning effect that lasted for one day. Water or tactile stimulus presented to an antenna was not effective for producing conditioning. The results demonstrate that gustatory US presented to an antenna is as effective as that presented to the mouth for producing salivary conditioning. This conditioning system provides a useful model for studying the neural basis of learning at the level of singly identifiable neurons.

  11. Suboptimal Choice in Pigeons: Stimulus Value Predicts Choice over Frequencies.

    PubMed

    Smith, Aaron P; Bailey, Alexandria R; Chow, Jonathan J; Beckmann, Joshua S; Zentall, Thomas R

    2016-01-01

    Pigeons have shown suboptimal gambling-like behavior when preferring a stimulus that infrequently signals reliable reinforcement over alternatives that provide greater reinforcement overall. As a mechanism for this behavior, recent research proposed that the stimulus value of alternatives with more reliable signals for reinforcement will be preferred relatively independently of their frequencies. The present study tested this hypothesis using a simplified design of a Discriminative alternative that, 50% of the time, led to either a signal for 100% reinforcement or a blackout period indicative of 0% reinforcement against a Nondiscriminative alternative that always led to a signal that predicted 50% reinforcement. Pigeons showed a strong preference for the Discriminative alternative that remained despite reducing the frequency of the signal for reinforcement in subsequent phases to 25% and then 12.5%. In Experiment 2, using the original design of Experiment 1, the stimulus following choice of the Nondiscriminative alternative was increased to 75% and then to 100%. Results showed that preference for the Discriminative alternative decreased only when the signals for reinforcement for the two alternatives predicted the same probability of reinforcement. The ability of several models to predict this behavior are discussed, but the terminal link stimulus value offers the most parsimonious account of this suboptimal behavior. PMID:27441394

  12. Businesses Angle for Share of School Stimulus Aid

    ERIC Educational Resources Information Center

    McNeil, Michele

    2009-01-01

    The prospect of sharing in the $100 billion in federal economic-stimulus aid has companies unleashing their sales pitches. Pittsburgh-based Apangea Learning, which offers online one-on-one tutoring, is offering school districts three years' worth of services for the price of two, to "help schools win new federal funding that is part of the Obama…

  13. Global inhibition and stimulus competition in the owl optic tectum

    PubMed Central

    Mysore, Shreesh P.; Asadollahi, Ali; Knudsen, Eric I.

    2010-01-01

    Stimulus selection for gaze and spatial attention involves competition among stimuli across sensory modalities and across all of space. We demonstrate that such cross-modal, global competition takes place in the intermediate and deep layers of the optic tectum, a structure known to be involved in gaze control and attention. A variety of either visual or auditory stimuli located anywhere outside of a neuron's receptive field (RF) were shown to suppress or completely eliminate responses to a visual stimulus located inside the RF in nitrous oxide sedated owls. The essential mechanism underlying this stimulus competition is global, divisive inhibition. Unlike the effect of the classical inhibitory surround, which decreases with distance from the RF center and shapes neuronal responses to individual stimuli, global inhibition acts across the entirety of space and modulates responses primarily in the context of multiple stimuli. Whereas the source of this global inhibition is as yet unknown, our data indicate that different networks mediate the classical surround and global inhibition. We hypothesize that this global, cross-modal inhibition, which acts automatically in a bottom-up fashion even in sedated animals, is critical to the creation of a map of stimulus salience in the optic tectum. PMID:20130182

  14. Nonautomated Procedures in Derived Stimulus Relations Research: A Methodological Note

    ERIC Educational Resources Information Center

    Dymond, Simon; Rehfeldt, Ruth Anne; Schenk, Jacqueline

    2005-01-01

    Nonautomated or tabletop procedures are widely used in derived stimulus relations research. These procedures offer several advantages to the researcher, not least of which is the interactive format of the task. However, this feature is often criticized because of the possibility of experimenter cuing and imprecise experimental control over task…

  15. Stimulus-based similarity and the recognition of spoken words

    NASA Astrophysics Data System (ADS)

    Auer, Edward T.

    2003-10-01

    Spoken word recognition has been hypothesized to be achieved via a competitive process amongst perceptually similar lexical candidates in the mental lexicon. In this process, lexical candidates are activated as a function of their perceived similarity to the spoken stimulus. The evidence supporting this hypothesis has largely come from studies of auditory word recognition. In this talk, evidence from our studies of visual spoken word recognition will be reviewed. Visual speech provides the opportunity to highlight the importance of stimulus-driven perceptual similarity because it presents a different pattern of segmental similarity than is afforded by auditory speech degraded by noise. Our results are consistent with stimulus-driven activation followed by competition as general spoken word recognition mechanism. In addition, results will be presented from recent investigations of the direct prediction of perceptual similarity from measurements of spoken stimuli. High levels of correlation have been observed between the predicted and perceptually obtained distances for a large set of spoken consonants. These results support the hypothesis that the perceptual structure of English consonants and vowels is predicted by stimulus structure without the need for an intervening level of abstract linguistic representation. [Research supported by NSF IIS 9996088 and NIH DC04856.

  16. A Dynamic Stimulus-Driven Model of Signal Detection

    ERIC Educational Resources Information Center

    Turner, Brandon M.; Van Zandt, Trisha; Brown, Scott

    2011-01-01

    Signal detection theory forms the core of many current models of cognition, including memory, choice, and categorization. However, the classic signal detection model presumes the a priori existence of fixed stimulus representations--usually Gaussian distributions--even when the observer has no experience with the task. Furthermore, the classic…

  17. Multidimensional Vector Model of Stimulus-Response Compatibility

    ERIC Educational Resources Information Center

    Yamaguchi, Motonori; Proctor, Robert W.

    2012-01-01

    The present study proposes and examines the multidimensional vector (MDV) model framework as a modeling schema for choice response times. MDV extends the Thurstonian model, as well as signal detection theory, to classification tasks by taking into account the influence of response properties on stimulus discrimination. It is capable of accounting…

  18. Stimulus-driven attentional capture by subliminal onset cues.

    PubMed

    Schoeberl, Tobias; Fuchs, Isabella; Theeuwes, Jan; Ansorge, Ulrich

    2015-04-01

    In two experiments, we tested whether subliminal abrupt onset cues capture attention in a stimulus-driven way. An onset cue was presented 16 ms prior to the stimulus display that consisted of clearly visible color targets. The onset cue was presented either at the same side as the target (the valid cue condition) or on the opposite side of the target (the invalid cue condition). Because the onset cue was presented 16 ms before other placeholders were presented, the cue was subliminal to the participant. To ensure that this subliminal cue captured attention in a stimulus-driven way, the cue's features did not match the top-down attentional control settings of the participants: (1) The color of the cue was always different than the color of the non-singleton targets ensuring that a top-down set for a specific color or for a singleton would not match the cue, and (2) colored targets and distractors had the same objective luminance (measured by the colorimeter) and subjective lightness (measured by flicker photometry), preventing a match between the top-down set for target and cue contrast. Even though a match between the cues and top-down settings was prevented, in both experiments, the cues captured attention, with faster response times in valid than invalid cue conditions (Experiments 1 and 2) and faster response times in valid than the neutral conditions (Experiment 2). The results support the conclusion that subliminal cues capture attention in a stimulus-driven way. PMID:25520044

  19. Generalization of Adult's Stimulus Control of Children's Behavior

    ERIC Educational Resources Information Center

    Redd, William H.

    1970-01-01

    Generalization of stimulus control in different situations and with novel adults occurred with those children who were trained by contingent reinforcement, but not with those trained by both contingent and noncontingent reinforcement. This research was submitted as part of the author's dissertation. (MH)

  20. Large Districts to Use Stimulus for ELL Support

    ERIC Educational Resources Information Center

    Zehr, Mary Ann

    2009-01-01

    At least four large urban school districts plan to spend a significant amount of their federal economic-stimulus money to support or improve programs for English-language learners, a fast-growing group in U.S. schools. The districts--Boston, New York City, St. Paul, Minnesota, and Seattle--have had varying degrees of success serving such students.…

  1. Effects of Compound Configuration on Stimulus Selection in the Pigeon

    ERIC Educational Resources Information Center

    Leith, Charles R.; Maki, William S., Jr.

    1977-01-01

    Whether a stimulus compound is separable or integral has predictable consequences for several human information processing tasks. The purpose of these experiments was to explore the implications of this distinction for research in animal learning and the development of learning theory. (Author/RK)

  2. Teaching Brain-Behavior Relations Economically with Stimulus Equivalence Technology

    ERIC Educational Resources Information Center

    Fienup, Daniel M.; Covey, Daniel P.; Critchfield, Thomas S.

    2010-01-01

    Instructional interventions based on stimulus equivalence provide learners with the opportunity to acquire skills that are not directly taught, thereby improving the efficiency of instructional efforts. The present report describes a study in which equivalence-based instruction was used to teach college students facts regarding brain anatomy and…

  3. Stimulus Overselectivity in Autism, Down Syndrome, and Typical Development

    ERIC Educational Resources Information Center

    Dube, William V.; Farber, Rachel S.; Mueller, Marlana R.; Grant, Eileen; Lorin, Lucy; Deutsch, Curtis K.

    2016-01-01

    Stimulus overselectivity refers to maladaptive narrow attending that is a common learning problem among children with intellectual disabilities and frequently associated with autism. The present study contrasted overselectivity among groups of children with autism, Down syndrome, and typical development. The groups with autism and Down syndrome…

  4. A selective role for dopamine in stimulus-reward learning.

    PubMed

    Flagel, Shelly B; Clark, Jeremy J; Robinson, Terry E; Mayo, Leah; Czuj, Alayna; Willuhn, Ingo; Akers, Christina A; Clinton, Sarah M; Phillips, Paul E M; Akil, Huda

    2011-01-01

    Individuals make choices and prioritize goals using complex processes that assign value to rewards and associated stimuli. During Pavlovian learning, previously neutral stimuli that predict rewards can acquire motivational properties, becoming attractive and desirable incentive stimuli. However, whether a cue acts solely as a predictor of reward, or also serves as an incentive stimulus, differs between individuals. Thus, individuals vary in the degree to which cues bias choice and potentially promote maladaptive behaviour. Here we use rats that differ in the incentive motivational properties they attribute to food cues to probe the role of the neurotransmitter dopamine in stimulus-reward learning. We show that intact dopamine transmission is not required for all forms of learning in which reward cues become effective predictors. Rather, dopamine acts selectively in a form of stimulus-reward learning in which incentive salience is assigned to reward cues. In individuals with a propensity for this form of learning, reward cues come to powerfully motivate and control behaviour. This work provides insight into the neurobiology of a form of stimulus-reward learning that confers increased susceptibility to disorders of impulse control.

  5. Stimulus characteristics within directives: effects on accuracy of task completion.

    PubMed Central

    Richman, D M; Wacker, D P; Cooper-Brown, L J; Kayser, K; Crosland, K; Stephens, T J; Asmus, J

    2001-01-01

    Three experiments were conducted in an outpatient setting with young children who had been referred for treatment of noncompliant behavior and who had coexisting receptive language or receptive vocabulary difficulties. Experiment 1 studied differential responding of the participants to a brief hierarchical directive analysis (least-to-most complex stimulus prompts) to identify directives that functioned as discriminative stimuli for accurate responding. Experiment 1 identified distinct patterns of accurate responding relative to manipulation of directive stimulus characteristics. Experiment 2 demonstrated that directives identified as effective or ineffective in obtaining stimulus control of accurate responding during Experiment 1 continued to control accurate responding across play activities and academic tasks. Experiment 3 probed effects of the interaction between the type of directive (effective vs. ineffective) and the reinforcement contingency (differential reinforcement for attempts vs. differential reinforcement for accurate responses) on accurate task completion and disruptive behavior. Results suggested that behavioral escalation from inaccurate responding to disruptive behavior occurred only when ineffective directives were combined with differential reinforcement for accurate task completion. The overall results are discussed in terms of developing a methodology for identifying stimulus characteristics of directives that affect accurate responding. PMID:11678525

  6. Anticipating Stimulus Money for Campus Projects, Colleges Get "Shovel Ready"

    ERIC Educational Resources Information Center

    Carlson, Scott

    2009-01-01

    Help for colleges may be on the way in the $825-billion stimulus package being pressed by Congressional leaders. The bill that House Democrats introduced this month includes $7-billion for higher-education modernization, renovation, and repair that could kick-start projects like upgrading heating and cooling systems, fixing roofs, and doing…

  7. Left neglect dyslexia and the effect of stimulus duration.

    PubMed

    Arduino, Lisa S; Vallar, Giuseppe; Burani, Cristina

    2006-01-01

    The present study investigated the effects of the duration of the stimulus on the reading performance of right-brain-damaged patients with left neglect dyslexia. Three Italian patients read aloud words and nonwords, under conditions of unlimited time of stimulus exposure and of timed presentation. In the untimed condition, the majority of the patients' errors involved the left side of the letter string (i.e., neglect dyslexia errors). Conversely, in the timed condition, although the overall level of performance decreased, errors were more evenly distributed across the whole letter string (i.e., visual - nonlateralized - errors). This reduction of neglect errors with a reduced time of presentation of the stimulus may reflect the read out of elements of the letter string from a preserved visual storage component, such as iconic memory. Conversely, a time-unlimited presentation of the stimulus may bring about the rightward bias that characterizes the performance of neglect patients, possibly by a capture of the patients' attention by the final (rightward) letters of the string.

  8. Promoting Response Variability and Stimulus Generalization in Martial Arts Training

    ERIC Educational Resources Information Center

    Harding, Jay W.; Wacker, David P.; Berg, Wendy K.; Rick, Gary; Lee, John F.

    2004-01-01

    The effects of reinforcement and extinction on response variability and stimulus generalization in the punching and kicking techniques of 2 martial arts students were evaluated across drill and sparring conditions. During both conditions, the students were asked to demonstrate different techniques in response to an instructor's punching attack.…

  9. Stimulus Characteristics Affect Humor Processing in Individuals with Asperger Syndrome

    ERIC Educational Resources Information Center

    Samson, Andrea C.; Hegenloh, Michael

    2010-01-01

    The present paper aims to investigate whether individuals with Asperger syndrome (AS) show global humor processing deficits or whether humor comprehension and appreciation depends on stimulus characteristics. Non-verbal visual puns, semantic and Theory of Mind cartoons were rated on comprehension, funniness and the punchlines were explained. AS…

  10. Crafting an Education Reform Agenda through Economic Stimulus Policy

    ERIC Educational Resources Information Center

    McDonnell, Lorraine M.; Weatherford, M. Stephen

    2011-01-01

    The economic stimulus enacted during President Obama's initial weeks included a down payment on his ambitious education reform agenda. By combining short-term policy with reform, the strategy gained his administration three advantages: a discretionary funding source with little Congressional scrutiny; flexibility in pursuing education reform goals…

  11. Stimulus Modality and Smoking Behavior: Moderating Role of Implicit Attitudes.

    PubMed

    Ezeh, Valentine C; Mefoh, Philip

    2015-07-20

    This study investigated whether stimulus modality influences smoking behavior among smokers in South Eastern Nigeria and also whether implicit attitudes moderate the relationship between stimulus modality and smoking behavior. 60 undergraduate students of University of Nigeria, Nsukka were used. Participants were individually administered the IAT task as a measure of implicit attitude toward smoking and randomly assigned into either image condition that paired images of cigarette with aversive images of potential health consequences or text condition that paired images of cigarette with aversive texts of potential health consequences. A one- predictor and one-moderator binary logistic analysis indicates that stimulus modality significantly predicts smoking behavior (p = < .05) with those in the image condition choosing not to smoke with greater probability than the text condition. The interaction between stimulus modality and IAT scores was also significant (p = < .05). Specifically, the modality effect was larger for participants in the image group who held more negative implicit attitudes towards smoking. The finding shows the urgent need to introduce the use of aversive images of potential health consequences on cigarette packs in Nigeria.

  12. Global inhibition and stimulus competition in the owl optic tectum.

    PubMed

    Mysore, Shreesh P; Asadollahi, Ali; Knudsen, Eric I

    2010-02-01

    Stimulus selection for gaze and spatial attention involves competition among stimuli across sensory modalities and across all of space. We demonstrate that such cross-modal, global competition takes place in the intermediate and deep layers of the optic tectum, a structure known to be involved in gaze control and attention. A variety of either visual or auditory stimuli located anywhere outside of a neuron's receptive field (RF) were shown to suppress or completely eliminate responses to a visual stimulus located inside the RF in nitrous oxide sedated owls. The essential mechanism underlying this stimulus competition is global, divisive inhibition. Unlike the effect of the classical inhibitory surround, which decreases with distance from the RF center and shapes neuronal responses to individual stimuli, global inhibition acts across the entirety of space and modulates responses primarily in the context of multiple stimuli. Whereas the source of this global inhibition is as yet unknown, our data indicate that different networks mediate the classical surround and global inhibition. We hypothesize that this global, cross-modal inhibition, which acts automatically in a bottom-up manner even in sedated animals, is critical to the creation of a map of stimulus salience in the optic tectum. PMID:20130182

  13. Compound Stimulus Extinction Reduces Spontaneous Recovery in Humans

    ERIC Educational Resources Information Center

    Coelho, Cesar A. O.; Dunsmoor, Joseph E.; Phelps, Elizabeth A.

    2015-01-01

    Fear-related behaviors are prone to relapse following extinction. We tested in humans a compound extinction design ("deepened extinction") shown in animal studies to reduce post-extinction fear recovery. Adult subjects underwent fear conditioning to a visual and an auditory conditioned stimulus (CSA and CSB, respectively) separately…

  14. Psilocybin-induced stimulus control in the rat.

    PubMed

    Winter, J C; Rice, K C; Amorosi, D J; Rabin, R A

    2007-10-01

    Although psilocybin has been trained in the rat as a discriminative stimulus, little is known of the pharmacological receptors essential for stimulus control. In the present investigation rats were trained with psilocybin and tests were then conducted employing a series of other hallucinogens and presumed antagonists. An intermediate degree of antagonism of psilocybin was observed following treatment with the 5-HT(2A) receptor antagonist, M100907. In contrast, no significant antagonism was observed following treatment with the 5-HT(1A/7) receptor antagonist, WAY-100635, or the DA D(2) antagonist, remoxipride. Psilocybin generalized fully to DOM, LSD, psilocin, and, in the presence of WAY-100635, DMT while partial generalization was seen to 2C-T-7 and mescaline. LSD and MDMA partially generalized to psilocybin and these effects were completely blocked by M-100907; no generalization of PCP to psilocybin was seen. The present data suggest that psilocybin induces a compound stimulus in which activity at the 5-HT(2A) receptor plays a prominent but incomplete role. In addition, psilocybin differs from closely related hallucinogens such as 5-MeO-DMT in that agonism at 5-HT(1A) receptors appears to play no role in psilocybin-induced stimulus control.

  15. Simon Effect with and without Awareness of the Accessory Stimulus

    ERIC Educational Resources Information Center

    Treccani, Barbara; Umilta, Carlo; Tagliabue, Mariaelena

    2006-01-01

    The authors investigated whether a Simon effect could be observed in an accessory-stimulus Simon task when participants were unaware of the task-irrelevant accessory cue. In Experiment 1A a central visual target was accompanied by a suprathreshold visual lateral cue. A regular Simon effect (i.e., faster cue-response corresponding reaction times…

  16. Suboptimal Choice in Pigeons: Stimulus Value Predicts Choice over Frequencies

    PubMed Central

    Bailey, Alexandria R.; Chow, Jonathan J.; Beckmann, Joshua S.; Zentall, Thomas R.

    2016-01-01

    Pigeons have shown suboptimal gambling-like behavior when preferring a stimulus that infrequently signals reliable reinforcement over alternatives that provide greater reinforcement overall. As a mechanism for this behavior, recent research proposed that the stimulus value of alternatives with more reliable signals for reinforcement will be preferred relatively independently of their frequencies. The present study tested this hypothesis using a simplified design of a Discriminative alternative that, 50% of the time, led to either a signal for 100% reinforcement or a blackout period indicative of 0% reinforcement against a Nondiscriminative alternative that always led to a signal that predicted 50% reinforcement. Pigeons showed a strong preference for the Discriminative alternative that remained despite reducing the frequency of the signal for reinforcement in subsequent phases to 25% and then 12.5%. In Experiment 2, using the original design of Experiment 1, the stimulus following choice of the Nondiscriminative alternative was increased to 75% and then to 100%. Results showed that preference for the Discriminative alternative decreased only when the signals for reinforcement for the two alternatives predicted the same probability of reinforcement. The ability of several models to predict this behavior are discussed, but the terminal link stimulus value offers the most parsimonious account of this suboptimal behavior. PMID:27441394

  17. The Effect of Stimulus Salience on Over-Selectivity

    ERIC Educational Resources Information Center

    Leader, Geraldine; Loughnane, Ann; McMoreland, Claire; Reed, Phil

    2009-01-01

    The influence of stimulus salience on over-selective responding was investigated in the context of a comparator theory of over-selectivity. In Experiments 1 and 2, participants were presented with two cards, each displaying two colors. In comparison to matched control participants, participants with Autistic Spectrum Disorder (ASD) demonstrated…

  18. Functional Fractionation of the Stimulus-Driven Attention Network

    PubMed Central

    2014-01-01

    A novel, salient event in the environment powerfully captures attention. This stimulus-driven attentional capture not only includes orienting of attention toward the event, but also an evaluative process to determine the behavioral significance and appropriate response to the event. Whereas a network of human brain regions composed of prefrontal and temporoparietal regions have been associated with stimulus-driven attention, the neural substrates of orienting have never been teased apart from those of evaluative processes. Here we used fMRI to measure the human brain's response to the temporally extended presentations of salient, task-irrelevant stimuli, and found a clear functional dissociation in the stimulus-driven attention network; the anterior insula and cingulate cortex showed transient orienting responses to the onsets and offsets of the stimuli, whereas the temporoparietal cortex exhibited sustained activity throughout event evaluation. The lateral prefrontal cortex was implicated in both attentional and evaluative processes, pointing to its central, integrative role in stimulus-driven attention. PMID:24828649

  19. Stimulus characteristics within directives: effects on accuracy of task completion.

    PubMed

    Richman, D M; Wacker, D P; Cooper-Brown, L J; Kayser, K; Crosland, K; Stephens, T J; Asmus, J

    2001-01-01

    Three experiments were conducted in an outpatient setting with young children who had been referred for treatment of noncompliant behavior and who had coexisting receptive language or receptive vocabulary difficulties. Experiment 1 studied differential responding of the participants to a brief hierarchical directive analysis (least-to-most complex stimulus prompts) to identify directives that functioned as discriminative stimuli for accurate responding. Experiment 1 identified distinct patterns of accurate responding relative to manipulation of directive stimulus characteristics. Experiment 2 demonstrated that directives identified as effective or ineffective in obtaining stimulus control of accurate responding during Experiment 1 continued to control accurate responding across play activities and academic tasks. Experiment 3 probed effects of the interaction between the type of directive (effective vs. ineffective) and the reinforcement contingency (differential reinforcement for attempts vs. differential reinforcement for accurate responses) on accurate task completion and disruptive behavior. Results suggested that behavioral escalation from inaccurate responding to disruptive behavior occurred only when ineffective directives were combined with differential reinforcement for accurate task completion. The overall results are discussed in terms of developing a methodology for identifying stimulus characteristics of directives that affect accurate responding.

  20. School Districts' Expenditure Responses to Federal Stimulus Funds

    ERIC Educational Resources Information Center

    Bourdeaux, Carolyn; Warner, Nicholas

    2015-01-01

    Between 2009 and 2011, school districts across the country received federal stimulus funds to shore up their budgets during the recession. The hope was that this support would serve as bridge funding during the recession, and that jurisdictions would then replace the federal funds as state and local tax bases grew stronger. However, the research…

  1. Common and differential electrophysiological mechanisms underlying semantic object memory retrieval probed by features presented in different stimulus types.

    PubMed

    Chiang, Hsueh-Sheng; Eroh, Justin; Spence, Jeffrey S; Motes, Michael A; Maguire, Mandy J; Krawczyk, Daniel C; Brier, Matthew R; Hart, John; Kraut, Michael A

    2016-08-01

    How the brain combines the neural representations of features that comprise an object in order to activate a coherent object memory is poorly understood, especially when the features are presented in different modalities (visual vs. auditory) and domains (verbal vs. nonverbal). We examined this question using three versions of a modified Semantic Object Retrieval Test, where object memory was probed by a feature presented as a written word, a spoken word, or a picture, followed by a second feature always presented as a visual word. Participants indicated whether each feature pair elicited retrieval of the memory of a particular object. Sixteen subjects completed one of the three versions (N=48 in total) while their EEG were recorded simultaneously. We analyzed EEG data in four separate frequency bands (delta: 1-4Hz, theta: 4-7Hz; alpha: 8-12Hz; beta: 13-19Hz) using a multivariate data-driven approach. We found that alpha power time-locked to response was modulated by both cross-modality (visual vs. auditory) and cross-domain (verbal vs. nonverbal) probing of semantic object memory. In addition, retrieval trials showed greater changes in all frequency bands compared to non-retrieval trials across all stimulus types in both response-locked and stimulus-locked analyses, suggesting dissociable neural subcomponents involved in binding object features to retrieve a memory. We conclude that these findings support both modality/domain-dependent and modality/domain-independent mechanisms during semantic object memory retrieval. PMID:27329353

  2. The influence of interaural stimulus uncertainty on binaural signal detection.

    PubMed

    Breebaart, J; Kohlrausch, A

    2001-01-01

    This paper investigated the influence of stimulus uncertainty in binaural detection experiments and the predictions of several binaural models for such conditions. Masked thresholds of a 500-Hz sinusoid were measured in an NrhoSpi condition for both running and frozen-noise maskers using a three interval, forced-choice (3IFC) procedure. The nominal masker correlation varied between 0.64 and 1, and the bandwidth of the masker was either 10, 100, or 1,000 Hz. The running-noise thresholds were expected to be higher than the frozen-noise thresholds because of stimulus uncertainty in the running-noise conditions. For an interaural correlation close to +1, no difference between frozen-noise and running-noise thresholds was expected for all values of the masker bandwidth. These expectations were supported by the experimental data: for interaural correlations less than 1.0, substantial differences between frozen and running-noise conditions were observed for bandwidths of 10 and 100 Hz. Two additional conditions were tested to further investigate the influence of stimulus uncertainty. In the first condition a different masker sample was chosen on each trial, but the correlation of the masker was forced to a fixed value. In the second condition one of two independent frozen-noise maskers was randomly chosen on each trial. Results from these experiments emphasized the influence of stimulus uncertainty in binaural detection tasks: if the degree of uncertainty in binaural cues was reduced, thresholds decreased towards thresholds in the conditions without any stimulus uncertainty. In the analysis of the data, stimulus uncertainty was expressed in terms of three theories of binaural processing: the interaural correlation, the EC theory, and a model based on the processing of interaural intensity differences (IIDs) and interaural time differences (ITDs). This analysis revealed that none of the theories tested could quantitatively account for the observed thresholds. In addition

  3. Contingent negative variation elicited before jaw and tongue movements.

    PubMed

    Yoshida, K; Iizuka, T

    2005-12-01

    Contingent negative variation (CNV) is a negative brain potential occurring between two successive stimuli when the first stimulus is a warning and the second stimulus requires a motor response. The CNV is interpreted as an expression of the cognitive processes in preparation for a response directed to a purpose. Using 19 electrodes we recorded CNVs for mouth opening, closing and lateral movements, tongue protrusion and hand extension in 10 healthy subjects. The aim of the study was to examine the motor control mechanism underlying jaw and tongue movements in a cognitive paradigm. The first stimulus (S1) served as a preparatory warning signal for the imperative stimulus (S2) 2 s after the S1. The subject performed the experimental tasks after the S2. The grand average CNVs for jaw and tongue movements showed a bilaterally widespread negativity with the maximum in the vertex region (Cz). The early CNV was identified about 400 ms after the S1 and its amplitude was highest at the midline-frontal area. The late CNV started approximately 1000 ms after the S1 with the maximum at Cz. The mean amplitude was significantly lower for hand extension than for the other tasks, and significantly higher for lateral movement than for mouth closing, suggesting that the CNV amplitude can be affected by the complexity of the task. The CNV recording may provide a means to study the neuronal activity necessary for the sensorimotor integration of jaw and tongue movements.

  4. Effect of telencephalon ablation on the reinforcing and eliciting properties of species-specific events in Betta splendens.

    PubMed

    Hollis, K L; Overmier, J B

    1982-08-01

    In male Betta splendens, aggressive behavior is drastically attenuated following telencephalon ablation. Because instrumental training and Pavlovian conditioning experiments with intact fish have suggested that associative factors may play an important role in the performance of agonistic behaviors, the effect of ablation on instrumental learning and Pavlovian conditioning was studied. In Experiment 1, ablation had no effect on the learning of the instrumental tunnel-swimming response reinforced by mirror presentation (i.e., viewing a conspecific), although the mirror presentations in yoked-control groups elicited fewer responses in ablates than in normal and sham-operated control fish. Yoked controls further established that instrumental responding was maintained by the reinforcement contingency and was not merely the result of increased motor activity. Experiment 2 studied Pavlovian conditioning of the components of the agonistic display. Unconditioned fin erection, gill erection, and tail beating (i.e., unconditioned responses, URs) to the mirror US all were less frequent in ablates than in normals or shams. Of these, only gill cover erection showed evidence of true conditioning (i.e., conditioned responses; CRs) in which responses to the conditioned stimulus (CS) are due to the pairings of CS and US (unconditioned stimulus). However, ablates suffered no impairment of conditioned gill erections. Ablates performed fewer fin erections to the CS; however, fin erection responses were not due to CS-US pairings but were attributable to pseudoconditioning. These results are related to hypotheses postulating the involvement of learning mechanisms in ablation-produced deficits and normal aggressive behavior.

  5. Recording evoked potentials during deep brain stimulation: development and validation of instrumentation to suppress the stimulus artefact

    NASA Astrophysics Data System (ADS)

    Kent, A. R.; Grill, W. M.

    2012-06-01

    The clinical efficacy of deep brain stimulation (DBS) for the treatment of movement disorders depends on the identification of appropriate stimulation parameters. Since the mechanisms of action of DBS remain unclear, programming sessions can be time consuming, costly and result in sub-optimal outcomes. Measurement of electrically evoked compound action potentials (ECAPs) during DBS, generated by activated neurons in the vicinity of the stimulating electrode, could offer insight into the type and spatial extent of neural element activation and provide a potential feedback signal for the rational selection of stimulation parameters and closed-loop DBS. However, recording ECAPs presents a significant technical challenge due to the large stimulus artefact, which can saturate recording amplifiers and distort short latency ECAP signals. We developed DBS-ECAP recording instrumentation combining commercial amplifiers and circuit elements in a serial configuration to reduce the stimulus artefact and enable high fidelity recording. We used an electrical circuit equivalent model of the instrumentation to understand better the sources of the stimulus artefact and the mechanisms of artefact reduction by the circuit elements. In vitro testing validated the capability of the instrumentation to suppress the stimulus artefact and increase gain by a factor of 1000 to 5000 compared to a conventional biopotential amplifier. The distortion of mock ECAP (mECAP) signals was measured across stimulation parameters, and the instrumentation enabled high fidelity recording of mECAPs with latencies of only 0.5 ms for DBS pulse widths of 50 to 100 µs/phase. Subsequently, the instrumentation was used to record in vivo ECAPs, without contamination by the stimulus artefact, during thalamic DBS in an anesthetized cat. The characteristics of the physiological ECAP were dependent on stimulation parameters. The novel instrumentation enables high fidelity ECAP recording and advances the potential use

  6. Representational similarity encoding for fMRI: Pattern-based synthesis to predict brain activity using stimulus-model-similarities.

    PubMed

    Anderson, Andrew James; Zinszer, Benjamin D; Raizada, Rajeev D S

    2016-03-01

    Patterns of neural activity are systematically elicited as the brain experiences categorical stimuli and a major challenge is to understand what these patterns represent. Two influential approaches, hitherto treated as separate analyses, have targeted this problem by using model-representations of stimuli to interpret the corresponding neural activity patterns. Stimulus-model-based-encoding synthesizes neural activity patterns by first training weights to map between stimulus-model features and voxels. This allows novel model-stimuli to be mapped into voxel space, and hence the strength of the model to be assessed by comparing predicted against observed neural activity. Representational Similarity Analysis (RSA) assesses models by testing how well the grand structure of pattern-similarities measured between all pairs of model-stimuli aligns with the same structure computed from neural activity patterns. RSA does not require model fitting, but also does not allow synthesis of neural activity patterns, thereby limiting its applicability. We introduce a new approach, representational similarity-encoding, that builds on the strengths of RSA and robustly enables stimulus-model-based neural encoding without model fitting. The approach therefore sidesteps problems associated with overfitting that notoriously confront any approach requiring parameter estimation (and is consequently low cost computationally), and importantly enables encoding analyses to be incorporated within the wider Representational Similarity Analysis framework. We illustrate this new approach by using it to synthesize and decode fMRI patterns representing the meanings of words, and discuss its potential biological relevance to encoding in semantic memory. Our new similarity-based encoding approach unites the two previously disparate methods of encoding models and RSA, capturing the strengths of both, and enabling similarity-based synthesis of predicted fMRI patterns.

  7. Expert elicitation on the uncertainties associated with chronic wasting disease.

    PubMed

    Tyshenko, Michael G; Oraby, Tamer; Darshan, Shalu; Westphal, Margit; Croteau, Maxine C; Aspinall, Willy; Elsaadany, Susie; Krewski, Daniel; Cashman, Neil

    2016-01-01

    A high degree of uncertainty exists for chronic wasting disease (CWD) transmission factors in farmed and wild cervids. Evaluating the factors is important as it helps to inform future risk management strategies. Expert opinion is often used to assist decision making in a number of health, science, and technology domains where data may be sparse or missing. Using the "Classical Model" of elicitation, a group of experts was asked to estimate the most likely values for several risk factors affecting CWD transmission. The formalized expert elicitation helped structure the issues and hence provide a rational basis for estimating some transmission risk factors for which evidence is lacking. Considered judgments regarding environmental transmission, latency of CWD transmission, management, and species barrier were provided by the experts. Uncertainties for many items were determined to be large, highlighting areas requiring more research. The elicited values may be used as surrogate values until research evidence becomes available. PMID:27556566

  8. Expert elicitation on the uncertainties associated with chronic wasting disease.

    PubMed

    Tyshenko, Michael G; Oraby, Tamer; Darshan, Shalu; Westphal, Margit; Croteau, Maxine C; Aspinall, Willy; Elsaadany, Susie; Krewski, Daniel; Cashman, Neil

    2016-01-01

    A high degree of uncertainty exists for chronic wasting disease (CWD) transmission factors in farmed and wild cervids. Evaluating the factors is important as it helps to inform future risk management strategies. Expert opinion is often used to assist decision making in a number of health, science, and technology domains where data may be sparse or missing. Using the "Classical Model" of elicitation, a group of experts was asked to estimate the most likely values for several risk factors affecting CWD transmission. The formalized expert elicitation helped structure the issues and hence provide a rational basis for estimating some transmission risk factors for which evidence is lacking. Considered judgments regarding environmental transmission, latency of CWD transmission, management, and species barrier were provided by the experts. Uncertainties for many items were determined to be large, highlighting areas requiring more research. The elicited values may be used as surrogate values until research evidence becomes available.

  9. Gender differences in preschoolers' help-eliciting communication.

    PubMed

    Thompson, R B

    1999-09-01

    Gender differences in help-eliciting communication and the relationship of such utterances with ability were explored. A sample of 71 preschoolers (38 boys, 33 girls; mean age 4 years 3 months) were videotaped as they solved a difficult puzzle. Spontaneous talk was analyzed for orientation (to whom or to what an utterance referred) and for the frequency of utterances coded as help eliciting. Significant main effects for gender were observed, with more frequent help-eliciting utterances (HEUs) made by the girls than by the boys, particularly HEUs about themselves (self-disclosing). Although the girls' HEUs were not predictive of ability on the puzzle, the boys' were. No gender differences in puzzle-solving ability were observed. Findings are discussed with regard to problem solving and social/linguistic development. PMID:10515069

  10. RESISTANCE TO EXTINCTION AND RELAPSE IN COMBINED STIMULUS CONTEXTS

    PubMed Central

    Podlesnik, Christopher A; Bai, John Y. H; Elliffe, Douglas

    2012-01-01

    Reinforcing an alternative response in the same context as a target response reduces the rate of occurrence but increases the persistence of that target response. Applied researchers who use such techniques to decrease the rate of a target problem behavior risk inadvertently increasing the persistence of the same problem behavior. Behavioral momentum theory asserts that the increased persistence is a function of the alternative reinforcement enhancing the Pavlovian relation between the target stimulus context and reinforcement. A method showing promise for reducing the persistence-enhancing effects of alternative reinforcement is to train the alternative response in a separate stimulus context before combining with the target stimulus in extinction. The present study replicated previous findings using pigeons by showing that combining an “alternative” richer VI schedule (96 reinforcers/hr) with a “target” leaner VI schedule (24 reinforcers/hr) reduced resistance to extinction of target responding compared with concurrent training of the alternative and target responses (totaling 120 reinforcers/hr). We also found less relapse with a reinstatement procedure following extinction with separate-context training, supporting previous findings that training conditions similarly influence both resistance to extinction and relapse. Finally, combining the alternative stimulus context was less disruptive to target responding previously trained in the concurrent schedule, relative to combining with the target response trained alone. Overall, the present findings suggest the technique of combining stimulus contexts associated with alternative responses with those associated with target responses disrupts target responding. Furthermore, the effectiveness of this disruption is a function of training context of reinforcement for target responding, consistent with assertions of behavioral momentum theory. PMID:23008521

  11. Adventitious Reinforcement of Maladaptive Stimulus Control Interferes with Learning.

    PubMed

    Saunders, Kathryn J; Hine, Kathleen; Hayashi, Yusuke; Williams, Dean C

    2016-09-01

    Persistent error patterns sometimes develop when teaching new discriminations. These patterns can be adventitiously reinforced, especially during long periods of chance-level responding (including baseline). Such behaviors can interfere with learning a new discrimination. They can also disrupt already learned discriminations, if they re-emerge during teaching procedures that generate errors. We present an example of this process. Our goal was to teach a boy with intellectual disabilities to touch one of two shapes on a computer screen (in technical terms, a simple simultaneous discrimination). We used a size-fading procedure. The correct stimulus was at full size, and the incorrect-stimulus size increased in increments of 10 %. Performance was nearly error free up to and including 60 % of full size. In a probe session with the incorrect stimulus at full size, however, accuracy plummeted. Also, a pattern of switching between choices, which apparently had been established in classroom instruction, re-emerged. The switching pattern interfered with already-learned discriminations. Despite having previously mastered a fading step with the incorrect stimulus up to 60 %, we were unable to maintain consistently high accuracy beyond 20 % of full size. We refined the teaching program such that fading was done in smaller steps (5 %), and decisions to "step back" to a smaller incorrect stimulus were made after every 5-instead of 20-trials. Errors were rare, switching behavior stopped, and he mastered the discrimination. This is a practical example of the importance of designing instruction that prevents adventitious reinforcement of maladaptive discriminated response patterns by reducing errors during acquisition. PMID:27622128

  12. Resistance to extinction and relapse in combined stimulus contexts.

    PubMed

    Podlesnik, Christopher A; Bai, John Y H; Elliffe, Douglas

    2012-09-01

    Reinforcing an alternative response in the same context as a target response reduces the rate of occurrence but increases the persistence of that target response. Applied researchers who use such techniques to decrease the rate of a target problem behavior risk inadvertently increasing the persistence of the same problem behavior. Behavioral momentum theory asserts that the increased persistence is a function of the alternative reinforcement enhancing the Pavlovian relation between the target stimulus context and reinforcement. A method showing promise for reducing the persistence-enhancing effects of alternative reinforcement is to train the alternative response in a separate stimulus context before combining with the target stimulus in extinction. The present study replicated previous findings using pigeons by showing that combining an "alternative" richer VI schedule (96 reinforcers/hr) with a "target" leaner VI schedule (24 reinforcers/hr) reduced resistance to extinction of target responding compared with concurrent training of the alternative and target responses (totaling 120 reinforcers/hr). We also found less relapse with a reinstatement procedure following extinction with separate-context training, supporting previous findings that training conditions similarly influence both resistance to extinction and relapse. Finally, combining the alternative stimulus context was less disruptive to target responding previously trained in the concurrent schedule, relative to combining with the target response trained alone. Overall, the present findings suggest the technique of combining stimulus contexts associated with alternative responses with those associated with target responses disrupts target responding. Furthermore, the effectiveness of this disruption is a function of training context of reinforcement for target responding, consistent with assertions of behavioral momentum theory.

  13. Dynamic stability of sequential stimulus representations in adapting neuronal networks

    PubMed Central

    Duarte, Renato C. F.; Morrison, Abigail

    2014-01-01

    The ability to acquire and maintain appropriate representations of time-varying, sequential stimulus events is a fundamental feature of neocortical circuits and a necessary first step toward more specialized information processing. The dynamical properties of such representations depend on the current state of the circuit, which is determined primarily by the ongoing, internally generated activity, setting the ground state from which input-specific transformations emerge. Here, we begin by demonstrating that timing-dependent synaptic plasticity mechanisms have an important role to play in the active maintenance of an ongoing dynamics characterized by asynchronous and irregular firing, closely resembling cortical activity in vivo. Incoming stimuli, acting as perturbations of the local balance of excitation and inhibition, require fast adaptive responses to prevent the development of unstable activity regimes, such as those characterized by a high degree of population-wide synchrony. We establish a link between such pathological network activity, which is circumvented by the action of plasticity, and a reduced computational capacity. Additionally, we demonstrate that the action of plasticity shapes and stabilizes the transient network states exhibited in the presence of sequentially presented stimulus events, allowing the development of adequate and discernible stimulus representations. The main feature responsible for the increased discriminability of stimulus-driven population responses in plastic networks is shown to be the decorrelating action of inhibitory plasticity and the consequent maintenance of the asynchronous irregular dynamic regime both for ongoing activity and stimulus-driven responses, whereas excitatory plasticity is shown to play only a marginal role. PMID:25374534

  14. Effect of target probability on pre-stimulus brain activity.

    PubMed

    Lucci, G; Berchicci, M; Perri, R L; Spinelli, D; Di Russo, F

    2016-05-13

    Studies on perceptual decision-making showed that manipulating the proportion of target and non-target stimuli affects the behavioral performance. Tasks with high frequency of targets are associated to faster response times (RTs) conjunctively to higher number of errors (reflecting a response bias characterized by speed/accuracy trade-off) when compared to conditions with low frequency of targets. Electroencephalographic studies well described modulations of post-stimulus event-related potentials as effect of the stimulus probability; in contrast, in the present study we focused on the pre-stimulus preparatory activities subtending the response bias. Two versions of a Go/No-go task characterized by different proportion of Go stimuli (88% vs. 12%) were adopted. In the task with frequent go trials, we observed a strong enhancement in the motor preparation as indexed by the Bereitschaftspotential (BP, previously associated with activity within the supplementary motor area), faster RTs, and larger commission error rate than in the task with rare go trials. Contemporarily with the BP, a right lateralized prefrontal negativity (lateral pN, previously associated with activity within the dorsolateral prefrontal cortex) was larger in the task with rare go trial. In the post-stimulus processing stage, we confirmed that the N2 and the P3 components were larger for rare trials, irrespective of the Go/No-go stimulus category. The increase of activities recorded in the preparatory phase related to frequency of targets is consistent with the view proposed in accumulation models of perceptual decision for which target frequency affects the subjective baseline, reducing the distance between the starting-point and the response boundary, which determines the response speed. PMID:26912279

  15. Resistance to extinction and relapse in combined stimulus contexts.

    PubMed

    Podlesnik, Christopher A; Bai, John Y H; Elliffe, Douglas

    2012-09-01

    Reinforcing an alternative response in the same context as a target response reduces the rate of occurrence but increases the persistence of that target response. Applied researchers who use such techniques to decrease the rate of a target problem behavior risk inadvertently increasing the persistence of the same problem behavior. Behavioral momentum theory asserts that the increased persistence is a function of the alternative reinforcement enhancing the Pavlovian relation between the target stimulus context and reinforcement. A method showing promise for reducing the persistence-enhancing effects of alternative reinforcement is to train the alternative response in a separate stimulus context before combining with the target stimulus in extinction. The present study replicated previous findings using pigeons by showing that combining an "alternative" richer VI schedule (96 reinforcers/hr) with a "target" leaner VI schedule (24 reinforcers/hr) reduced resistance to extinction of target responding compared with concurrent training of the alternative and target responses (totaling 120 reinforcers/hr). We also found less relapse with a reinstatement procedure following extinction with separate-context training, supporting previous findings that training conditions similarly influence both resistance to extinction and relapse. Finally, combining the alternative stimulus context was less disruptive to target responding previously trained in the concurrent schedule, relative to combining with the target response trained alone. Overall, the present findings suggest the technique of combining stimulus contexts associated with alternative responses with those associated with target responses disrupts target responding. Furthermore, the effectiveness of this disruption is a function of training context of reinforcement for target responding, consistent with assertions of behavioral momentum theory. PMID:23008521

  16. Role of 5-HT2A and 5-HT2C receptors in the stimulus effects of hallucinogenic drugs. II: Reassessment of LSD false positives.

    PubMed

    Fiorella, D; Rabin, R A; Winter, J C

    1995-10-01

    In the context of animal studies of hallucinogens, an LSD-false positive is defined as a drug known to be devoid of hallucinogenic activity in humans but which nonetheless fully mimics LSD in animals. Quipazine, MK-212, lisuride, and yohimbine have all been reported to be LSD false positives. The present study was designed to determine whether these compounds also substitute for the stimulus effects of the more pharmacologically selective hallucinogen (-)DOM (0.56 mg/kg, 75-min pretreatment time). The LSD and (-)DOM stimuli fully generalized to quipazine (3.0 mg/kg) and lisuride (0.2 mg/kg), but only partially generalized to MK-212 (0.1-1.0 mg/kg) and yohimbine (2-20 mg/kg). In combination tests, pirenpirone (0.08 mg/kg), a compound with both D2 and 5-HT2A affinity, blocked the substitution of quipazine and lisuride for the (-)DOM stimulus. Ketanserin (2.5 mg/kg), an antagonist with greater than 1 order of magnitude higher affinity for 5-HT2A receptors than either 5-HT2C or D2 receptors, also fully blocked the substitution of these compounds for the (-)DOM stimulus, while the selective D2 antagonist thiothixene (0.1-1.0 mg/kg) failed to block the substitution of lisuride for the (-)DOM stimulus. These results suggest that quipazine and lisuride substitute for the stimulus properties of the phenylalkglamine hallucinogen (-)DOM via agonist activity at 5-HT2A receptors. In addition, these results suggest that 5-HT2A agonist activity may be required, but is not in itself sufficient, for indolamine and phenylalkglamine compounds to elicit hallucinations in humans. Finally, it is concluded that MK-212 and yohimbine are neither LSD nor (-)DOM false positives.

  17. Reductions in central venous pressure by lower body negative pressure or blood loss elicit similar hemodynamic responses

    PubMed Central

    Johnson, Blair D.; van Helmond, Noud; Curry, Timothy B.; van Buskirk, Camille M.; Convertino, Victor A.

    2014-01-01

    The purpose of this study was to compare hemodynamic and blood analyte responses to reduced central venous pressure (CVP) and pulse pressure (PP) elicited during graded lower body negative pressure (LBNP) to those observed during graded blood loss (BL) in conscious humans. We hypothesized that the stimulus-response relationships of CVP and PP to hemodynamic responses during LBNP would mimic those observed during BL. We assessed CVP, PP, heart rate, mean arterial pressure (MAP), and other hemodynamic markers in 12 men during LBNP and BL. Blood samples were obtained for analysis of catecholamines, hematocrit, hemoglobin, arginine vasopressin, and blood gases. LBNP consisted of 5-min stages at 0, 15, 30, and 45 mmHg of suction. BL consisted of 5 min at baseline and following three stages of 333 ml of hemorrhage (1,000 ml total). Individual r2 values and linear regression slopes were calculated to determine whether the stimulus (CVP and PP)-hemodynamic response trajectories were similar between protocols. The CVP-MAP trajectory was the only CVP-response slope that was statistically different during LBNP compared with BL (0.93 ± 0.27 vs. 0.13 ± 0.26; P = 0.037). The PP-heart rate trajectory was the only PP-response slope that was statistically different during LBNP compared with BL (−1.85 ± 0.45 vs. −0.46 ± 0.27; P = 0.024). Norepinephrine, hematocrit, and hemoglobin were all lower at termination in the BL protocol compared with LBNP (P < 0.05). Consistent with our hypothesis, LBNP mimics the hemodynamic stimulus-response trajectories observed during BL across a significant range of CVP in humans. PMID:24876357

  18. Regulation of Pancreatic Beta Cell Stimulus-Secretion Coupling by microRNAs

    PubMed Central

    Esguerra, Jonathan L. S.; Mollet, Inês G.; Salunkhe, Vishal A.; Wendt, Anna; Eliasson, Lena

    2014-01-01

    Increased blood glucose after a meal is countered by the subsequent increased release of the hypoglycemic hormone insulin from the pancreatic beta cells. The cascade of molecular events encompassing the initial sensing and transport of glucose into the beta cell, culminating with the exocytosis of the insulin large dense core granules (LDCVs) is termed “stimulus-secretion coupling.” Impairment in any of the relevant processes leads to insufficient insulin release, which contributes to the development of type 2 diabetes (T2D). The fate of the beta cell, when exposed to environmental triggers of the disease, is determined by the possibility to adapt to the new situation by regulation of gene expression. As established factors of post-transcriptional regulation, microRNAs (miRNAs) are well-recognized mediators of beta cell plasticity and adaptation. Here, we put focus on the importance of comprehending the transcriptional regulation of miRNAs, and how miRNAs are implicated in stimulus-secretion coupling, specifically those influencing the late stages of insulin secretion. We suggest that efficient beta cell adaptation requires an optimal balance between transcriptional regulation of miRNAs themselves, and miRNA-dependent gene regulation. The increased knowledge of the beta cell transcriptional network inclusive of non-coding RNAs such as miRNAs is essential in identifying novel targets for the treatment of T2D. PMID:25383562

  19. Integration of auditory and vibrotactile stimuli: Effects of phase and stimulus-onset asynchrony

    PubMed Central

    Wilson, E. Courtenay; Reed, Charlotte M.; Braida, Louis D.

    2009-01-01

    The perceptual integration of 250 Hz, 500 ms vibrotactile and auditory tones was studied in detection experiments as a function of (1) relative phase and (2) temporal asynchrony of the tone pulses. Vibrotactile stimuli were delivered through a single-channel vibrator to the left middle fingertip and auditory stimuli were presented diotically through headphones in a background of 50 dB sound pressure level broadband noise. The vibrotactile and auditory stimulus levels used each yielded 63%–77%-correct unimodal detection performance in a 2-I, 2-AFC task. Results for combined vibrotactile and auditory detection indicated that (1) performance improved for synchronous presentation, (2) performance was not affected by the relative phase of the auditory and tactile sinusoidal stimuli, and (3) performance for non-overlapping stimuli improved only if the tactile stimulus preceded the auditory. The results are generally more consistent with a “Pythagorean Sum” model than with either an “Algebraic Sum” or an “Optimal Single-Channel” Model of perceptual integration. Thus, certain combinations of auditory and tactile signals result in significant integrative effects. The lack of phase effect suggests an envelope rather than fine-structure operation for integration. The effects of asynchronous presentation of the auditory and tactile stimuli are consistent with time constants deduced from single-modality masking experiments. PMID:19813808

  20. Effects of contrast, spatial frequency, and stimulus duration on reaction time in rats.

    PubMed

    Kurylo, Daniel D; Chung, Caroline; Yeturo, Sowmya; Lanza, Joseph; Gorskaya, Arina; Bukhari, Farhan

    2015-01-01

    Early visual processing in rats is mediated by several pre-cortical pathways as well as multiple retinal ganglion cell types that vary in response characteristics. Discrete processing is thereby optimized for select ranges of stimulus parameters. In order to explore variation in response characteristics at a perceptual level, visual detection in rats was measured across a range of contrasts, spatial frequencies, and durations. Rats responded to the onset of Gabor patches. Onset time occurred after a random delay, and reaction time (RT) frequency distribution served to index target visibility. It was found that lower spatial frequency produced shorter RTs, as well as increased RT equivalent of contrast gain. Brief stimulus presentation reduced target visibility, slowed RTs, and reduced contrast gain at higher spatial frequencies. However, brief stimuli shortened RTs at low contrasts and low spatial frequencies, suggesting transient stimuli are more efficiently processed under these conditions. Collectively, perceptual characteristics appear to reflect distinctions in neural responses at early stages of processing. The RT characteristics found here may thereby reflect the contribution of multiple channels, and suggest a progressive shift in relative involvement across parameter levels.

  1. Robust preprocessing for stimulus-based functional MRI of the moving fetus.

    PubMed

    You, Wonsang; Evangelou, Iordanis E; Zun, Zungho; Andescavage, Nickie; Limperopoulos, Catherine

    2016-04-01

    Fetal motion manifests as signal degradation and image artifact in the acquired time series of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) studies. We present a robust preprocessing pipeline to specifically address fetal and placental motion-induced artifacts in stimulus-based fMRI with slowly cycled block design in the living fetus. In the proposed pipeline, motion correction is optimized to the experimental paradigm, and it is performed separately in each phase as well as in each region of interest (ROI), recognizing that each phase and organ experiences different types of motion. To obtain the averaged BOLD signals for each ROI, both misaligned volumes and noisy voxels are automatically detected and excluded, and the missing data are then imputed by statistical estimation based on local polynomial smoothing. Our experimental results demonstrate that the proposed pipeline was effective in mitigating the motion-induced artifacts in stimulus-based fMRI data of the fetal brain and placenta. PMID:27081665

  2. Robust preprocessing for stimulus-based functional MRI of the moving fetus.

    PubMed

    You, Wonsang; Evangelou, Iordanis E; Zun, Zungho; Andescavage, Nickie; Limperopoulos, Catherine

    2016-04-01

    Fetal motion manifests as signal degradation and image artifact in the acquired time series of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) studies. We present a robust preprocessing pipeline to specifically address fetal and placental motion-induced artifacts in stimulus-based fMRI with slowly cycled block design in the living fetus. In the proposed pipeline, motion correction is optimized to the experimental paradigm, and it is performed separately in each phase as well as in each region of interest (ROI), recognizing that each phase and organ experiences different types of motion. To obtain the averaged BOLD signals for each ROI, both misaligned volumes and noisy voxels are automatically detected and excluded, and the missing data are then imputed by statistical estimation based on local polynomial smoothing. Our experimental results demonstrate that the proposed pipeline was effective in mitigating the motion-induced artifacts in stimulus-based fMRI data of the fetal brain and placenta.

  3. The blink reflex magnitude is continuously adjusted according to both current and predicted stimulus position with respect to the face.

    PubMed

    Wallwork, Sarah B; Talbot, Kerwin; Camfferman, Danny; Moseley, G L; Iannetti, G D

    2016-08-01

    The magnitude of the hand-blink reflex (HBR), a subcortical defensive reflex elicited by the electrical stimulation of the median nerve, is increased when the stimulated hand is close to the face ('far-near effect'). This enhancement occurs through a cortico-bulbar facilitation of the polysynaptic medullary pathways subserving the reflex. Here, in two experiments, we investigated the temporal characteristics of this facilitation, and its adjustment during voluntary movement of the stimulated hand. Given that individuals navigate in a fast changing environment, one would expect the cortico-bulbar modulation of this response to adjust rapidly, and as a function of the predicted spatial position of external threats. We observed two main results. First, the HBR modulation occurs without a temporal delay between when the hand has reached the stimulation position and when the stimulus happens (Experiments 1 and 2). Second, the voluntary movement of the hand interacts with the 'far-near effect': stimuli delivered when the hand is far from the face elicit an enhanced HBR if the hand is being moved towards the face, whereas stimuli delivered when the hand is near the face elicit an enhanced HBR regardless of the direction of the hand movement (Experiment 2). These results indicate that the top-down modulation of this subcortical defensive reflex occurs continuously, and takes into account both the current and the predicted position of potential threats with respect to the body. The continuous control of the excitability of subcortical reflex circuits ensures appropriate adjustment of defensive responses in a rapidly-changing sensory environment. PMID:27236372

  4. The Elicited Language Inventory and the Influence of Contextual Cues.

    ERIC Educational Resources Information Center

    Nelson, Lauren K.; Weber-Olsen, Marcia

    1980-01-01

    The Elicited Language Inventory (ELI) was administered in standardized fashion and in a modified procedure with contextually supported cues and grammatical morpheme use under the two ELI presentation conditions was compared with use of the same morphemes in spontaneous speech. Results favored modified use of the ELI with contextually cued items…

  5. Clinicians as Communication Partners: Developing a Mediated Discourse Elicitation Protocol

    ERIC Educational Resources Information Center

    Hengst, Julie A.; Duff, Melissa C.

    2007-01-01

    This article presents the development and piloting of a mediated discourse elicitation protocol. Grounded in situated theories of communication and informed by mediated discourse analysis, this protocol selectively samples familiar discourse types in a manner designed to preserve interactional aspects of communication. Critically, the mediated…

  6. Eliciting Students' Beliefs about Who Is Good at Mathematics

    ERIC Educational Resources Information Center

    Morge, Shelby P.

    2007-01-01

    This article highlights a series of activities designed to elicit students' mathematics-related beliefs, particularly those related to gender. As a result of the activities, females in upper-level classes rated themselves as having less confidence than males, and viewing a movie clip was sufficient for some students to modify their descriptions of…

  7. Modification of commercially available simulators to elicit decision making behavior.

    PubMed

    Salud, Jonathan; Ononye, Chiagozie; Salud, Lawrence; Pugh, Carla

    2012-01-01

    In recent years, simulation training has emerged as an innovative method for decreasing error and teaching complex procedures. Simulation has also been a valuable tool for evaluating investigatory and analytic thinking. By adding a specific, clinically oriented modification to a commercially available simulator, we were able to elicit first-year emergency medicine resident perceptions, actions, and decisions.

  8. Eliciting Design Patterns for E-Learning Systems

    ERIC Educational Resources Information Center

    Retalis, Symeon; Georgiakakis, Petros; Dimitriadis, Yannis

    2006-01-01

    Design pattern creation, especially in the e-learning domain, is a highly complex process that has not been sufficiently studied and formalized. In this paper, we propose a systematic pattern development cycle, whose most important aspects focus on reverse engineering of existing systems in order to elicit features that are cross-validated through…

  9. Eliciting Production of L2 Target Structures through Priming Activities

    ERIC Educational Resources Information Center

    McDonough, Kim; Trofimovich, Pavel; Neumann, Heike

    2015-01-01

    This study focuses on the pedagogical applications of structural priming research in an English for academic purposes (EAP) context, investigating whether priming activities are an effective tool for eliciting production of target grammatical structures. University students across four EAP classes carried out a total of 6 information-exchange…

  10. Computational Support for Early Elicitation and Classification of Tone

    ERIC Educational Resources Information Center

    Bird, Steven; Lee, Haejoong

    2014-01-01

    Investigating a tone language involves careful transcription of tone on words and phrases. This is challenging when the phonological categories--the tones or melodies--have not been identified. Effects such as coarticulation, sandhi, and phrase-level prosody appear as obstacles to early elicitation and classification of tone. This article presents…

  11. Photo-Elicitation: Reflexivity on Method, Analysis, and Graphic Portraits

    ERIC Educational Resources Information Center

    Richard, Veronica M.; Lahman, Maria K. E.

    2015-01-01

    In this methodological discussion, the authors detail and reflect on the processes of using photo-elicitation interviewing as a way to align with positive qualitative methodologies, to gain access to participant beliefs and values, and to highlight participant voices through their choices of words and visuals. A review of the literature and an…

  12. Engaging Young Children in Research through Photo Elicitation

    ERIC Educational Resources Information Center

    Pyle, Angela

    2013-01-01

    Embracing the new sociology of childhood, this paper describes a participatory research method built on a belief in the competency of young children. The paper begins with a critical review of the photo elicitation literature exploring the varied levels of children's participation. Drawing on the strengths of the previous research, a…

  13. Creating a Framework: Art Therapy Elicits the Narrative

    ERIC Educational Resources Information Center

    Harber, Karen

    2011-01-01

    A case study illustrates how art therapy was used to elicit the narrative of an adolescent male student in transition from incarceration to a transfer school setting. Childhood trauma was addressed in individual sessions and within a literacy group co-led by a reading specialist. The art therapist responded to the client's needs by broadening the…

  14. The Role of Elicited Verbal Imitation in Toddlers' Word Learning

    ERIC Educational Resources Information Center

    Hodges, Rosemary; Munro, Natalie; Baker, Elise; McGregor, Karla; Docking, Kimberley; Arciuli, Joanne

    2016-01-01

    This study is about the role of elicited verbal imitation in toddler word learning. Forty-eight toddlers were taught eight nonwords linked to referents. During training, they were asked to imitate the nonwords. Naming of the referents was tested at three intervals (one minute later [uncued], five minutes, and 1-7 days later [cued]) and recognition…

  15. A Study of the Affective Responses Elicited by Occupational Stimuli

    ERIC Educational Resources Information Center

    Schoon, Craig G.

    1976-01-01

    The semantic differential was used to assess the properties of affect elicited by occupational stimuli. Vocationally committed men studying medicine, business, and engineering responded to a semantic differential containing occupational concepts. Results show a semantic space for all three groups composed of three orthogonal dimensions of affect…

  16. Elicited Role-Play of Commands and Requests.

    ERIC Educational Resources Information Center

    Strage, Amy; And Others

    Children's ability to understand the implied messages in indirect speech was investigated using a role play elicitation task. Subjects were asked to complete story endings using puppets for several scenerios involving a mother and her four children. In each of the stories the mother gives an indirect directive which is supposed to get the children…

  17. Elicited Production of Relative Clauses in Children with Williams Syndrome

    ERIC Educational Resources Information Center

    Zukowski, Andrea

    2009-01-01

    Relative clauses have been implicated alternately as a strength and a weakness in the language of people with Williams Syndrome (WS). To clarify the facts, an elicited production test was administered to 10 people with WS (age 10-16 years), 10 typically developing children (age 4-7 years), and 12 typically developing adults. Nearly every WS…

  18. Using Automatic Speech Recognition Technology with Elicited Oral Response Testing

    ERIC Educational Resources Information Center

    Cox, Troy L.; Davies, Randall S.

    2012-01-01

    This study examined the use of automatic speech recognition (ASR) scored elicited oral response (EOR) tests to assess the speaking ability of English language learners. It also examined the relationship between ASR-scored EOR and other language proficiency measures and the ability of the ASR to rate speakers without bias to gender or native…

  19. Elicitation Support Requirements of Multi-Expertise Teams

    ERIC Educational Resources Information Center

    Bitter-Rijpkema, Marlies; Martens, Rob; Jochems, Wim

    2005-01-01

    Tools to support knowledge elicitation are used more and more in situations where employees or students collaborate using the computer. Studies indicate that differences exist between experts and novices regarding their methods of work and reasoning. However, the commonly preferred approach tends to deal with team members as a single system with…

  20. A Task that Elicits Reasoning: A Dual Analysis

    ERIC Educational Resources Information Center

    Yankelewitz, Dina; Mueller, Mary; Maher, Carolyn A.

    2010-01-01

    This paper reports on the forms of reasoning elicited as fourth grade students in a suburban district and sixth grade students in an urban district worked on similar tasks involving reasoning with the use of Cuisenaire rods. Analysis of the two data sets shows similarities in the reasoning used by both groups of students on specific tasks, and the…

  1. Teacher Burnout and Self-Efficacy in Eliciting Social Support.

    ERIC Educational Resources Information Center

    Brouwers, Andre; Evers, Will J. G.; Tomic, Welko

    This study examined the relationship between perceived lack of social support, perceived self-efficacy in eliciting support at the workplace, and the three successive burnout symptoms (emotional exhaustion, depersonalization, and personal accomplishment) in a sample of 277 Dutch secondary school teachers. The study hypothesized that teachers'…

  2. Preparing Beginning Teachers to Elicit and Interpret Students' Mathematical Thinking

    ERIC Educational Resources Information Center

    Sleep, Laurie; Boerst, Timothy A.

    2012-01-01

    This study investigated how teacher education assignments can be designed to support beginning teachers in learning to do the work of teaching. We examined beginners' formative assessment practices--in particular, their eliciting and interpreting of students' mathematical thinking--in the context of an elementary mathematics methods assignment,…

  3. Stimulus specificity and dishabituation of operant responding in humans.

    PubMed

    Kenzer, Amy L; Ghezzi, Patrick M; Fuller, Timothy

    2013-07-01

    Habituation has recently been addressed within the operant conditioning paradigm. While the literature on this topic is growing, the examination of dishabituation, a fundamental characteristic of habituation, remains limited. This study expanded research on habituation of operant responding in non-human animals to research involving humans. Specifically, dishabituation and stimulus specificity were examined under a variety of conditions involving changes in the reinforcer type, reinforcement schedule, reinforcer amount, and selected properties of the antecedent stimuli for a computerized task with 46 undergraduate students. An additional 3 participants were exposed to a control condition. Evaluation of within session patterns of responding indicates that the introduction of stimulus changes into the operant context reliably produced dishabituation of operant responding in humans.

  4. The effect of stimulus bandwidth on binaural loudness summation.

    PubMed

    Shao, Zhiyue; Mo, Fangshuo; Mao, Dongxing

    2015-09-01

    Binaural loudness summation is an important property of the human auditory system. This paper presents an experimental investigation of how binaural loudness summation varies with stimulus bandwidth. Loudness matches were obtained between dichotic stimuli, with interaural level differences (ILDs) of 2-12 dB, and diotic stimuli. The stimuli were noise bands with seven center frequencies and four bandwidths. Results showed that the loudness of dichotic stimuli increased nonlinearly with ILD, the increase being slightly less with broader bandwidths. There was a bandwidth-dependent difference between the listening tests results and the predictions of Moore and Glasberg's [(2007) J. Acoust. Soc. Am. 121, 1604-1612] loudness model. The size of the difference was, however, small. A characteristic function was derived describing how overall loudness depends on stimulus bandwidth and ILD. PMID:26428788

  5. Gambling with stimulus payments: feeding gaming machines with federal dollars.

    PubMed

    Lye, Jenny; Hirschberg, Joe

    2014-09-01

    In late 2008 and early 2009 the Australian Federal Government introduced a series of economic stimulus packages designed to maintain consumer spending in the early days of the Great Recession. When these packages were initiated the media suggested that the wide-spread availability of electronic gaming machines (EGMs, e.g. slot machines, poker machines, video lottery terminals) in Australia would result in stimulating the EGMs. Using state level monthly data we estimate that the stimulus packages led to an increase of 26 % in EGM revenues. This also resulted in over $60 million in additional tax revenue for State Governments. We also estimate a short-run aggregate income demand elasticity for EGMs to be approximately 2.

  6. How odgcrnwi becomes crowding: stimulus-specific learning reduces crowding.

    PubMed

    Huckauf, Anke; Nazir, Tatjana A

    2007-08-16

    Processes underlying crowding in visual letter recognition were examined by investigating effects of training. Experiment 1 revealed that training reduces crowding mainly for trained strings. This was corroborated in Experiment 2, where no training effects were obvious after 3 days of training when strings changed from trial to trial. Experiment 3 specified that after a short amount of training, learning effects remained specific to trained strings and also to the trained retinal eccentricity and the interletter spacing used in training. Transfer to other than trained conditions was observed only after further training. Experiment 4 showed that transfer occurred earlier when words were used as stimuli. These results thus demonstrate that part of crowding results from the absence of higher level representations of the stimulus. Such representations can be acquired through learning visual properties of the stimulus.

  7. Reduction of stimulus overselectivity with nonverbal differential observing responses.

    PubMed

    Dube, W V; McIlvane, W J

    1999-01-01

    Three individuals with mental retardation exhibited stimulus overselectivity in a delayed matching-to-sample task in which two sample stimuli were displayed on each trial. Intermediate accuracy scores indicated that participants could match one of the samples but not both of them. Accuracy in a baseline condition was compared to accuracy with a differential observing response procedure. This procedure prompted participants to make simultaneous identity-matching responses that required observation and discrimination of both sample stimuli. These observing responses were never followed by differential consequences. When observing responses were prompted, participants' accuracy scores improved. In a return to the baseline condition, when differential observing responses were no longer prompted, accuracy returned to intermediate levels. The results show that stimulus overselectivity can be greatly reduced by a behavioral intervention that controls observing behavior and verifies discrimination, but that exposure to such procedures alone may be insufficient for lasting benefits.

  8. NMDA receptor antagonist MK-801 blocks learning of conditioned stimulus-unconditioned stimulus contiguity but not fear of conditioned stimulus in goldfish (Carassius auratus L.).

    PubMed

    Davis, R E; Klinger, P D

    1994-10-01

    The blockade of learning of Pavlovian fear conditioning by the N-methyl-D-aspartic acid (NMDA)-receptor antagonist MK-801 was examined in 166 goldfish. In previously untrained fish, MK-801 blocked learning of a light-off or a tone conditioned stimulus (CS) paired with an electrical shock unconditioned stimulus (US). Pretraining on the light-off CS did not affect the rate of learning of the tone CS but protected the tone learning from disruption by MK-801. Switching from the light-off to the tone CS changed the identity of the CS but not its temporal contiguity with the US. Pretraining consisting of pseudoconditioning of the light-off CS did not protect subsequent tone learning from blockade by MK-801. Thus, the NMDA receptor functions are necessary for learning related to the temporal contiguity of the CS and US but not to the identity of the CS as a cue to the occurrence of the fearful effects of the US.

  9. Effect of eye position on the projected stimulus distance in a binocular head-mounted display

    NASA Astrophysics Data System (ADS)

    McCandless, Jeffrey W.; Ellis, Stephen R.

    2000-05-01

    During vergence eye movements, the effective separation between the two eyes varies because the nodal point of each eye is offset from the center of rotation. As a result, the projected distance of a binocularly presented virtual object changes as the observer converges and diverges. A model of eye and stimulus position illustrates that if an observer converges toward a binocular virtual stimulus that is fixed on the display, the projected stimulus will shift outward away from the observer. Conversely, if the observer diverges toward a binocular virtual stimulus that is fixed on the display, the projected stimulus will shift inward. For example, if an observer diverges from 25 cm to 300 cm, a binocular virtual stimulus projected at 300 cm will shift inward to 241 cm. Accurate depiction of a fixed stimulus distance in a binocular display requires that the stimulus position on the display surface should be adjusted in real- time to compensate for the observer's eye movements.

  10. Stimulus-dependent refractoriness in the Frankenhaeuser-Huxley model.

    PubMed

    Morse, R P; Allingham, D; Stocks, N G

    2015-10-01

    Phenomenological neural models, such as the leaky integrate-and-fire model, normally have a fixed refractory time-course that is independent of the stimulus. The recovery of threshold following an action potential is typically based on physiological experiments that use a two-pulse paradigm in which the first pulse is suprathreshold and causes excitation and the second pulse is used to determine the threshold at various intervals following the first. In such experiments, the nerve is completely unstimulated between the two pulses. This contrasts the receptor stimuli in normal physiological systems and the electrical stimuli used by cochlear implants and other neural prostheses. A numerical study of the Frankenhaeuser-Huxley conductance-based model of nerve fibre was therefore undertaken to investigate the effect of stimulation on refractoriness. We found that the application of a depolarizing stimulus during the later part of what is classically regarded as the absolute refractory period could effectively prolong the absolute refractory period, while leaving the refractory time-constants and other refractory parameters largely unaffected. Indeed, long depolarizing pulses, which would have been suprathreshold if presented to a resting nerve fibre, appeared to block excitation indefinitely. Stimulation during what is classically regarded as the absolute refractory period can therefore greatly affect the temporal response of a nerve. We conclude that the classical definition of absolute refractory period should be refined to include only the initial period following an action potential when an ongoing stimulus would not affect threshold; this period was found to be about half as long as the classical absolute refractory period. We further conclude that the stimulus-dependent nature of the relative refractory period must be considered when developing a phenomenological nerve model for complex stimuli.

  11. Posthypnotic use of olfactory stimulus for pain management.

    PubMed

    Bubenzer, Theresa; Huang, Hsiang

    2014-01-01

    Chronic pain due to disease or injury persists even after interventions to alleviate these conditions. Opiates are not always effective for the patient and have undesirable side effects. Hypnosis has been shown to be an effective treatment and may be enhanced by the use of olfactory stimulation as a posthypnotic cue. The article details 2 case reports that demonstrate the possible benefits of olfactory stimulus as an adjunct to hypnosis for pain relief. PMID:24568325

  12. Stimulus-dependent refractoriness in the Frankenhaeuser-Huxley model.

    PubMed

    Morse, R P; Allingham, D; Stocks, N G

    2015-10-01

    Phenomenological neural models, such as the leaky integrate-and-fire model, normally have a fixed refractory time-course that is independent of the stimulus. The recovery of threshold following an action potential is typically based on physiological experiments that use a two-pulse paradigm in which the first pulse is suprathreshold and causes excitation and the second pulse is used to determine the threshold at various intervals following the first. In such experiments, the nerve is completely unstimulated between the two pulses. This contrasts the receptor stimuli in normal physiological systems and the electrical stimuli used by cochlear implants and other neural prostheses. A numerical study of the Frankenhaeuser-Huxley conductance-based model of nerve fibre was therefore undertaken to investigate the effect of stimulation on refractoriness. We found that the application of a depolarizing stimulus during the later part of what is classically regarded as the absolute refractory period could effectively prolong the absolute refractory period, while leaving the refractory time-constants and other refractory parameters largely unaffected. Indeed, long depolarizing pulses, which would have been suprathreshold if presented to a resting nerve fibre, appeared to block excitation indefinitely. Stimulation during what is classically regarded as the absolute refractory period can therefore greatly affect the temporal response of a nerve. We conclude that the classical definition of absolute refractory period should be refined to include only the initial period following an action potential when an ongoing stimulus would not affect threshold; this period was found to be about half as long as the classical absolute refractory period. We further conclude that the stimulus-dependent nature of the relative refractory period must be considered when developing a phenomenological nerve model for complex stimuli. PMID:26187096

  13. Benzodiazepine-like discriminative stimulus effects of toluene vapor

    PubMed Central

    Shelton, Keith L.; Nicholson, Katherine L.

    2013-01-01

    In vitro studies show that the abused inhalant toluene affects a number of ligand-gated ion channels. The two most consistently implicated of these are γ-aminobutyric acid type A (GABAA) receptors which are positively modulated by toluene and N-methyl-D-aspartate (NMDA) receptors which are negatively modulated by toluene. Behavioral studies also suggest an interaction of toluene with GABAA and/or NMDA receptors but it is unclear if these receptors underlie the abuse-related intoxicating effects of toluene. Seventeen B6SJLF1/J mice were trained using a two-choice operant drug discrimination procedure to discriminate 10 min of exposure to 2000 ppm toluene vapor from 10 min of exposure to air. The discrimination was acquired in a mean of 65 training sessions. The stimulus effects of 2000 ppm toluene vapor were exposure concentration-dependent but rapidly diminished following the cessation of vapor exposure. The stimulus effects of toluene generalized to the chlorinated hydrocarbon vapor perchloroethylene but not 1,1,2-trichloroethane nor the volatile anesthetic isoflurane. The competitive NMDA antagonist CGS-17955, the uncompetitive antagonist dizocilpine and the glycine-site antagonist L701,324 all failed to substitute for toluene. The classical nonselective benzodiazepines midazolam and chlordiazepoxide produced toluene-like stimulus effects but the alpha 1 subunit preferring positive GABAA modulator zaleplon failed to substitute for toluene. The barbiturates pentobarbital and methohexital and the GABAA-positive modulator neurosteroid allopregnanolone did not substitute for toluene. These data suggest that the stimulus effects of toluene may be at least partially mediated by benzodiazepine-like positive allosteric modulation of GABAA receptors containing alpha 2, 3 or 5 subunits. PMID:24436974

  14. The Physiological Stimulus for the BarA Sensor Kinase▿

    PubMed Central

    Gonzalez Chavez, Ricardo; Alvarez, Adrian F.; Romeo, Tony; Georgellis, Dimitris

    2010-01-01

    The two-component signal transduction system (TCS) BarA/UvrY activates transcription of CsrB and CsrC noncoding RNAs, which act by sequestering the RNA-binding global regulatory protein CsrA. Here, we show that the metabolic end products formate and acetate provide a physiological stimulus for this TCS and thus link posttranscriptional regulation by the Csr system to the metabolic state of the cell. PMID:20118252

  15. High Stimulus-Related Information in Barrel Cortex Inhibitory Interneurons.

    PubMed

    Reyes-Puerta, Vicente; Kim, Suam; Sun, Jyh-Jang; Imbrosci, Barbara; Kilb, Werner; Luhmann, Heiko J

    2015-06-01

    The manner in which populations of inhibitory (INH) and excitatory (EXC) neocortical neurons collectively encode stimulus-related information is a fundamental, yet still unresolved question. Here we address this question by simultaneously recording with large-scale multi-electrode arrays (of up to 128 channels) the activity of cell ensembles (of up to 74 neurons) distributed along all layers of 3-4 neighboring cortical columns in the anesthetized adult rat somatosensory barrel cortex in vivo. Using two different whisker stimulus modalities (location and frequency) we show that individual INH neurons--classified as such according to their distinct extracellular spike waveforms--discriminate better between restricted sets of stimuli (≤6 stimulus classes) than EXC neurons in granular and infra-granular layers. We also demonstrate that ensembles of INH cells jointly provide as much information about such stimuli as comparable ensembles containing the ~20% most informative EXC neurons, however presenting less information redundancy - a result which was consistent when applying both theoretical information measurements and linear discriminant analysis classifiers. These results suggest that a consortium of INH neurons dominates the information conveyed to the neocortical network, thereby efficiently processing incoming sensory activity. This conclusion extends our view on the role of the inhibitory system to orchestrate cortical activity.

  16. High Stimulus-Related Information in Barrel Cortex Inhibitory Interneurons

    PubMed Central

    Reyes-Puerta, Vicente; Kim, Suam; Sun, Jyh-Jang; Imbrosci, Barbara; Kilb, Werner; Luhmann, Heiko J.

    2015-01-01

    The manner in which populations of inhibitory (INH) and excitatory (EXC) neocortical neurons collectively encode stimulus-related information is a fundamental, yet still unresolved question. Here we address this question by simultaneously recording with large-scale multi-electrode arrays (of up to 128 channels) the activity of cell ensembles (of up to 74 neurons) distributed along all layers of 3–4 neighboring cortical columns in the anesthetized adult rat somatosensory barrel cortex in vivo. Using two different whisker stimulus modalities (location and frequency) we show that individual INH neurons – classified as such according to their distinct extracellular spike waveforms – discriminate better between restricted sets of stimuli (≤6 stimulus classes) than EXC neurons in granular and infra-granular layers. We also demonstrate that ensembles of INH cells jointly provide as much information about such stimuli as comparable ensembles containing the ~20% most informative EXC neurons, however presenting less information redundancy – a result which was consistent when applying both theoretical information measurements and linear discriminant analysis classifiers. These results suggest that a consortium of INH neurons dominates the information conveyed to the neocortical network, thereby efficiently processing incoming sensory activity. This conclusion extends our view on the role of the inhibitory system to orchestrate cortical activity. PMID:26098109

  17. Selectivity for multiple stimulus features in retinal ganglion cells.

    PubMed

    Fairhall, Adrienne L; Burlingame, C Andrew; Narasimhan, Ramesh; Harris, Robert A; Puchalla, Jason L; Berry, Michael J

    2006-11-01

    Under normal viewing conditions, retinal ganglion cells transmit to the brain an encoded version of the visual world. The retina parcels the visual scene into an array of spatiotemporal features, and each ganglion cell conveys information about a small set of these features. We study the temporal features represented by salamander retinal ganglion cells by stimulating with dynamic spatially uniform flicker and recording responses using a multi-electrode array. While standard reverse correlation methods determine a single stimulus feature--the spike-triggered average--multiple features can be relevant to spike generation. We apply covariance analysis to determine the set of features to which each ganglion cell is sensitive. Using this approach, we found that salamander ganglion cells represent a rich vocabulary of different features of a temporally modulated visual stimulus. Individual ganglion cells were sensitive to at least two and sometimes as many as six features in the stimulus. While a fraction of the cells can be described by a filter-and-fire cascade model, many cells have feature selectivity that has not previously been reported. These reverse models were able to account for 80-100% of the information encoded by ganglion cells. PMID:16914609

  18. Stimulus factors affecting the categorisation of faces and scrambled faces.

    PubMed

    Donnelly, N; Humphreys, G W; Sawyer, J

    1994-05-01

    Three experiments are reported which investigate the categorisation of faces and scrambled faces in a face/scrambled face decision task. Three kinds of stimuli were presented in upright and inverted orientations; faces, highly scrambled faces (all features out of position) and moderately scrambled faces (two features out of position). Experiment 1 demonstrated that faces and highly scrambled faces are categorised equally quickly and both types of stimulus were categorised faster than moderately scrambled faces. These results held for both upright and inverted presentations. It is argued that for both upright and inverted presentations, faces are categorised by being matched in parallel to a stored mental representation of a face. In contrast scrambled faces are categorised following a serial search of facial features which is probably self-terminating. Experiment 2 demonstrates that the results of Experiment 1 hold when facial features are replaced by other objects which retain the same global shape as facial features and suggest that faces are categorised using a coarsely coded visual description. Experiment 3 demonstrates the importance of stimulus outline on the categorisation of both moderately and highly scrambled faces but not real faces. The results are discussed in terms of the stimulus information used, and the effect of inversion, on face categorisation.

  19. Stimulus-Response-Outcome Coding in the Pigeon Nidopallium Caudolaterale

    PubMed Central

    Starosta, Sarah; Güntürkün, Onur; Stüttgen, Maik C.

    2013-01-01

    A prerequisite for adaptive goal-directed behavior is that animals constantly evaluate action outcomes and relate them to both their antecedent behavior and to stimuli predictive of reward or non-reward. Here, we investigate whether single neurons in the avian nidopallium caudolaterale (NCL), a multimodal associative forebrain structure and a presumed analogue of mammalian prefrontal cortex, represent information useful for goal-directed behavior. We subjected pigeons to a go-nogo task, in which responding to one visual stimulus (S+) was partially reinforced, responding to another stimulus (S–) was punished, and responding to test stimuli from the same physical dimension (spatial frequency) was inconsequential. The birds responded most intensely to S+, and their response rates decreased monotonically as stimuli became progressively dissimilar to S+; thereby, response rates provided a behavioral index of reward expectancy. We found that many NCL neurons' responses were modulated in the stimulus discrimination phase, the outcome phase, or both. A substantial fraction of neurons increased firing for cues predicting non-reward or decreased firing for cues predicting reward. Interestingly, the same neurons also responded when reward was expected but not delivered, and could thus provide a negative reward prediction error or, alternatively, signal negative value. In addition, many cells showed motor-related response modulation. In summary, NCL neurons represent information about the reward value of specific stimuli, instrumental actions as well as action outcomes, and therefore provide signals useful for adaptive behavior in dynamically changing environments. PMID:23437383

  20. Evidence for response membership in stimulus classes by pigeons.

    PubMed

    Urcuioli, Peter J; Jones, B Max; Lionello-DeNolf, Karen M

    2013-03-01

    Response membership in pigeons' stimulus-class formation was evaluated using associative symmetry and class expansion tests. In Experiment 1, pigeons learned hue-hue (AA) and form-form (BB) successive matching plus a modified hue-form (AB) task in which reinforcement was contingent upon a left versus right side-key response after the positive AB sequences. On subsequent BA (symmetry) probe trials, pigeons responded more often to the comparisons on the reverse of the positive than negative AB sequences and, more importantly, preferentially pecked the side key consistent with symmetry after the reversed positive sequences. In Experiment 2, the original three baseline tasks were supplemented by dot-white (CC) successive matching in which reinforcement was contingent upon a left versus right side-key response after the positive CC sequences. Class expansion was then tested by presenting nonreinforced CA and CB successive matching probes. Comparison response rates were mostly nondifferential on CA probes but were uniformly higher on CB probes that consisted of the C samples and B comparisons from the same, hypothesized class. Together, these results provide evidence that responses can become members of stimulus classes, as predicted by Urcuioli's (2008) theory of pigeons' stimulus-class formation and Sidman's (2000) theory of equivalence.

  1. Two different mechanisms for the detection of stimulus omission

    PubMed Central

    Ohmae, Shogo; Tanaka, Masaki

    2016-01-01

    Although we can detect slight changes in musical rhythm, the underlying neural mechanism remains elusive. Here we show that two distinct mechanisms are automatically selected depending on the speed of the rhythm. When human subjects detected a single omission of isochronous repetitive auditory stimuli, reaction time strongly depended on the stimulus onset asynchrony (SOA) for shorter SOAs (<250 ms), but was almost constant for longer SOAs. For shorter SOAs, subjects were unable to detect stimulus omission when either monaural stimuli or those in different frequencies were randomly presented. In contrast, for longer SOAs, reaction time increased when different tempos were presented simultaneously to different ears. These results suggest that depending on the speed of rhythms, the brain may use either temporal grouping of discrete sounds or temporal prediction of upcoming stimuli to detect the absence of a regular stimulus. Because we also found a similar relationship between reaction time and SOA for both visual and tactile stimuli, dual detection strategies could be generalized to other sensory modalities. PMID:26847381

  2. Evidence for response membership in stimulus classes by pigeons.

    PubMed

    Urcuioli, Peter J; Jones, B Max; Lionello-DeNolf, Karen M

    2013-03-01

    Response membership in pigeons' stimulus-class formation was evaluated using associative symmetry and class expansion tests. In Experiment 1, pigeons learned hue-hue (AA) and form-form (BB) successive matching plus a modified hue-form (AB) task in which reinforcement was contingent upon a left versus right side-key response after the positive AB sequences. On subsequent BA (symmetry) probe trials, pigeons responded more often to the comparisons on the reverse of the positive than negative AB sequences and, more importantly, preferentially pecked the side key consistent with symmetry after the reversed positive sequences. In Experiment 2, the original three baseline tasks were supplemented by dot-white (CC) successive matching in which reinforcement was contingent upon a left versus right side-key response after the positive CC sequences. Class expansion was then tested by presenting nonreinforced CA and CB successive matching probes. Comparison response rates were mostly nondifferential on CA probes but were uniformly higher on CB probes that consisted of the C samples and B comparisons from the same, hypothesized class. Together, these results provide evidence that responses can become members of stimulus classes, as predicted by Urcuioli's (2008) theory of pigeons' stimulus-class formation and Sidman's (2000) theory of equivalence. PMID:23413094

  3. The role of stimulus cross-splicing in an event-related potentials study. Misleading formant transitions hinder automatic phonological processing.

    PubMed

    Steinberg, Johanna; Truckenbrodt, Hubert; Jacobsen, Thomas

    2012-04-01

    The mental organization of linguistic knowledge and its involvement in speech processing can be investigated using the mismatch negativity (MMN) component of the auditory event-related potential. A contradiction arises, however, between the technical need for strict control of acoustic stimulus properties and the quest for naturalness and acoustic variability of the stimuli. Here, two methods of preparing speech stimulus material were compared. Focussing on the automatic processing of a phonotactic restriction in German, two corresponding sets of various vowel-fricative syllables were used as stimuli. The former syllables were naturally spoken while the latter ones were created by means of cross-splicing. Phonetically, natural and spliced syllables differed with respect to the appropriateness of coarticulatory information about the forthcoming fricative within the vowels. Spliced syllables containing clearly misleading phonetic information were found to elicit larger N2 responses compared to their natural counterparts. Furthermore, MMN results found for the natural syllables could not be replicated with these spliced stimuli. These findings indicate that the automatic processing of the stimuli was considerably affected by the stimulus preparation method. Thus, in spite of its unquestioned benefits for MMN experiments, the splicing technique may lead to interference effects on the linguistic factors under investigation. PMID:22501085

  4. Direction of an approaching stimulus on coincident timing performance of a ballistic striking task.

    PubMed

    Coker, Cheryl A

    2005-06-01

    The purpose of this study was to explore the influence of stimulus direction and velocity on the coincident timing performance of a ballistic striking task. 26 subjects randomly performed 20 trials at each of two stimulus velocities (4 and 8 mph) and two striking variations (moving with an approaching stimulus or in opposition to it). Analysis indicated the direction of an approaching stimulus does not appear to influence the coincident timing of a ballistic striking action.

  5. Spatial stimulus-response compatibility and affordance effects are not ruled by the same mechanisms

    PubMed Central

    Ambrosecchia, Marianna; Marino, Barbara F. M.; Gawryszewski, Luiz G.; Riggio, Lucia

    2015-01-01

    Stimulus position is coded even if it is task-irrelevant, leading to faster response times when the stimulus and the response locations are compatible (spatial Stimulus–Response Compatibility–spatial SRC). Faster responses are also found when the handle of a visual object and the response hand are located on the same side; this is known as affordance effect (AE). Two contrasting accounts for AE have been classically proposed. One is focused on the recruitment of appropriate grasping actions on the object handle, and the other on the asymmetry in the object shape, which in turn would cause a handle-hand correspondence effect (CE). In order to disentangle these two accounts, we investigated the possible transfer of practice in a spatial SRC task executed with a S–R incompatible mapping to a subsequent affordance task in which objects with either their intact handle or a broken one were used. The idea was that using objects with broken handles should prevent the recruitment of motor information relative to object grasping, whereas practice transfer should prevent object asymmetry in driving handle-hand CE. A total of three experiments were carried out. In Experiment 1 participants underwent an affordance task in which common graspable objects with their intact or broken handle were used. In Experiments 2 and 3, the affordance task was preceded by a spatial SRC task in which an incompatible S–R mapping was used. Inter-task delays of 5 or 30 min were employed to assess the duration of transfer effect. In Experiment 2 objects with their intact handle were presented, whereas in Experiment 3 the same objects had their handle broken. Although objects with intact and broken handles elicited a handle-hand CE in Experiment 1, practice transfer from an incompatible spatial SRC to the affordance task was found in Experiment 3 (broken-handle objects), but not in Experiment 2 (intact-handle objects). Overall, this pattern of results indicate that both object asymmetry and

  6. Bi-directional changes in affective state elicited by manipulation of medullary pain-modulatory circuitry.

    PubMed

    Hirakawa, N; Tershner, S A; Fields, H L; Manning, B H

    2000-01-01

    The rostral ventromedial medulla contains three physiologically defined classes of pain-modulating neuron that project to the spinal and trigeminal dorsal horns. OFF cells contribute to anti-nociceptive processes, ON cells contribute to pro-nociceptive processes (i.e. hyperalgesia) and neutral cells tonically modulate spinal nociceptive responsiveness. In the setting of noxious peripheral input, the different cell classes in this region permit bi-directional modulation of pain perception (analgesia vs hyperalgesia). It is unclear, however, whether changes in the activity of these neurons are relevant to the behaving animal in the absence of a painful stimulus. Here, we pharmacologically manipulated neurons in the rostral ventromedial medulla and used the place-conditioning paradigm to assess changes in the affective state of the animal. Local microinjection of the alpha(1)-adrenoceptor agonist methoxamine (50.0 microg in 0.5 microl; to activate ON cells, primarily), combined with local microinjection of the kappa-opioid receptor agonist U69,593 (0.178 microg in 0.5 microl; to inhibit OFF cells), produced an increase in spinal nociceptive reactivity (i.e. hyperalgesia on the tail flick assay) and a negative affective state (as inferred from the production of conditioned place avoidance) in the conscious, freely moving rat. Additional microinjection experiments using various concentrations of methoxamine alone or U69, 593 alone revealed that the rostral ventromedial medulla is capable of eliciting a range of affective changes resulting in conditioned place avoidance, no place-conditioning effect or conditioned place preference (reflecting production of a positive affective state). Overall, however, there was no consistent relationship between place-conditioning effects and changes in spinal nociceptive reactivity. This is the first report of bi-directional changes in affective state (i.e. reward or aversion production) associated with pharmacological manipulation of

  7. Bi-directional changes in affective state elicited by manipulation of medullary pain-modulatory circuitry.

    PubMed

    Hirakawa, N; Tershner, S A; Fields, H L; Manning, B H

    2000-01-01

    The rostral ventromedial medulla contains three physiologically defined classes of pain-modulating neuron that project to the spinal and trigeminal dorsal horns. OFF cells contribute to anti-nociceptive processes, ON cells contribute to pro-nociceptive processes (i.e. hyperalgesia) and neutral cells tonically modulate spinal nociceptive responsiveness. In the setting of noxious peripheral input, the different cell classes in this region permit bi-directional modulation of pain perception (analgesia vs hyperalgesia). It is unclear, however, whether changes in the activity of these neurons are relevant to the behaving animal in the absence of a painful stimulus. Here, we pharmacologically manipulated neurons in the rostral ventromedial medulla and used the place-conditioning paradigm to assess changes in the affective state of the animal. Local microinjection of the alpha(1)-adrenoceptor agonist methoxamine (50.0 microg in 0.5 microl; to activate ON cells, primarily), combined with local microinjection of the kappa-opioid receptor agonist U69,593 (0.178 microg in 0.5 microl; to inhibit OFF cells), produced an increase in spinal nociceptive reactivity (i.e. hyperalgesia on the tail flick assay) and a negative affective state (as inferred from the production of conditioned place avoidance) in the conscious, freely moving rat. Additional microinjection experiments using various concentrations of methoxamine alone or U69, 593 alone revealed that the rostral ventromedial medulla is capable of eliciting a range of affective changes resulting in conditioned place avoidance, no place-conditioning effect or conditioned place preference (reflecting production of a positive affective state). Overall, however, there was no consistent relationship between place-conditioning effects and changes in spinal nociceptive reactivity. This is the first report of bi-directional changes in affective state (i.e. reward or aversion production) associated with pharmacological manipulation of

  8. 75 FR 36063 - Expansion and Extension of the Patent Application Backlog Reduction Stimulus Plan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-24

    ... Stimulus Plan, 74 FR 62285 (Nov. 27, 2009), 1349 Off. Gaz. Pat. Off. 304 (Dec. 22, 2009) (hereinafter.... See Patent Application Backlog Reduction Stimulus Plan, 74 FR at 62287, 1349 Off. Gaz. Pat. Off. at.... See Extension of the Patent Application Backlog Reduction Stimulus Plan, 75 FR 5041 (Feb. 1,...

  9. Stimulus-Seeking, Extraversion, and Neuroticism in Regular, Occasional, and Non-Exercisers.

    ERIC Educational Resources Information Center

    Burgess, Sharon S.; Pargman, David

    To test the hypothesis that stimulus-seeking and extraversion underlie "exercise addiction" and sport involvement, the relationships among stimulus-seeking, extraversion, and exercise frequency were examined in ninety males matched on age and educational level. The Stimulus Variation Seeking Scale, Sensation-Seeking Scale (SSS) and Eysenck…

  10. Examination of the Prevalence of Stimulus Overselectivity in Children with ASD

    ERIC Educational Resources Information Center

    Rieth, Sarah R.; Stahmer, Aubyn C.; Suhrheinrich, Jessica; Schreibman, Laura

    2015-01-01

    Many individuals with autism spectrum disorders (ASD) display stimulus overselectivity, wherein a subset of relevant components in a compound stimulus controls responding, which impairs discrimination learning. The original experimental research on stimulus overselectivity in ASD was conducted several decades ago; however, interventions for…

  11. Temporary Activation of Perceptual-Motor Associations: A Stimulus-Response Interpretation of Automaticity

    ERIC Educational Resources Information Center

    Klapp, Stuart T.; Greenberg, Lisa A.

    2009-01-01

    Some types of automaticity can be attributed to simple stimulus-response associations (G. D. Logan, 1988). This can be studied with paradigms in which associations to an irrelevant stimulus automatically influence responding to a relevant stimulus. In 1 example, the irrelevant and relevant stimuli were presented successively with the 1st,…

  12. Duration Discrimination in Listeners with Cochlear Hearing Loss: Effects of Stimulus Type and Frequency

    ERIC Educational Resources Information Center

    Grose, John H.; Hall, Joseph W., III; Buss, Emily

    2004-01-01

    This study examined the effects of cochlear hearing loss on the ability to discriminate increments in the duration of a stimulus under conditions where the frequency and/or amplitude of the stimulus change dynamically. Three stimulus types were used: pure tones, frequency-modulated tones, and narrow bands of noise. The carrier/center frequency of…

  13. Additive Effects of Stimulus Quality and Word Frequency on Eye Movements during Chinese Reading

    ERIC Educational Resources Information Center

    Liu, Pingping; Li, Xingshan; Han, Buxin

    2015-01-01

    Eye movements of Chinese readers were recorded for sentences in which high- and low-frequency target words were presented normally or with reduced stimulus quality in two experiments. We found stimulus quality and word frequency produced strong additive effects on fixation durations for target words. The results demonstrate that stimulus quality…

  14. Stimulus Fading and Differential Reinforcement for the Treatment of Needle Phobia in a Youth with Autism

    ERIC Educational Resources Information Center

    Shabani, Daniel B.; Fisher, Wayne W.

    2006-01-01

    Stimulus fading in the form of gradually increased exposure to a fear-evoking stimulus, often combined with differential reinforcement, has been used to treat phobias in children who are otherwise normal and in children with autism. In this investigation, we applied stimulus fading plus differential reinforcement with an adolescent with autism and…

  15. Within-Subject Reversibility of Discriminative Function in the Composite-Stimulus Control of Behavior

    ERIC Educational Resources Information Center

    Weiss, Stanley J.; Kearns, David N.; Antoshina, Maria

    2009-01-01

    According to the composite-stimulus control model (Weiss, 1969, 1972b), an individual discriminative stimulus (S[superscript D]) is composed of that S[superscript D]'s on-state plus the off-states of all other relevant S[superscript D]s. The present experiment investigated the reversibility of composite-stimulus control. Separate groups of rats…

  16. Discriminative stimulus properties of indorenate, a serotonin agonist.

    PubMed Central

    Velázquez-Martínez, D N; López Cabrera, M; Sánchez, H; Ramírez, J I; Hong, E

    1999-01-01

    OBJECTIVE: To determine whether indorenate, a serotonin-receptor agonist, can exert discriminative control over operant responses, to establish the temporal course of discriminative control and to compare its stimulus properties to a (5-HT)IA receptor agonist. [3H]-8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT). DESIGN: Prospective animal study. ANIMALS: Ten male Wistar rats. INTERVENTIONS: Rats were trained to press either of 2 levers for sucrose solution according to a fixed ratio schedule, which was gradually increased. Rats were given injections of either indorenate or saline solution during discrimination training. Once they had achieved an 83% accuracy rate, rats underwent generalization tests after having received a different dose of indorenate, the training dose of indorenate at various intervals before the test, various doses of 8-OH-DPT, or NAN-190 administered before indorenate or 8-OH-DPAT. OUTCOME MEASURES: Distribution of responses between the 2 levers before the first reinforcer of the session, response rate for all the responses in the session, and a discrimination index that expressed the drug-appropriate responses as a proportion of the total responses. RESULTS: Indorenate administration resulted in discriminative control over operant responses, maintained at fixed ratio 10, at a dose of 10.0 mg/kg (but not 3.0 mg/kg). When the interval between the administration of indorenate and the start of the session was varied, the time course of its cue properties followed that of its described effects on 5-HT turnover. In generalization tests, the discrimination index was a function of the dose of indorenate employed; moreover, administration of 8-OH-DPAT (from 0.1 to 1.0 mg/kg) fully mimicked the stimulus properties of indorenate in a dose-dependent way. The (5-HT)IA antagonist NAN-190 prevented the stimulus generalization from indorenate to 8-OH-DPAT. Also, NAN-190 antagonized the stimulus control of indorenate when administered 45 minutes before

  17. Nonlinear Analyses of Elicited Modal, Raised, and Pressed Rabbit Phonation

    PubMed Central

    Awan, Shaheen N.; Novaleski, Carolyn K.; Rousseau, Bernard

    2014-01-01

    Objectives/Hypothesis The purpose of this study was to use nonlinear dynamic analysis methods such as phase space portraits and correlation dimension (D2) as well as descriptive spectrographic analyses to characterize acoustic signals produced during evoked rabbit phonation. Methods Seventeen New Zealand white breeder rabbits were used to perform the study. A Grass S-88 stimulator (SA Instrumentation, Encinitas, CA) and constant current isolation unit (Grass Telefactor, model PSIU6; West Warwick, RI) were used to provide electrical stimulation to laryngeal musculature, and transglottal airflow rate and stimulation current (mA) were manipulated to elicit modal, raised intensity, and pressed phonations. Central 1 second portions of the most stable portion of the acoustic waveform for modal, raised intensity, and pressed phonations were edited, and then analyzed via phase space portraits, Poincaré sections, and the estimation of the correlation dimension (D2). In an attempt to limit the effects of the highly variable and nonstationary characteristics of some of the signals being analyzed, D2 analysis was also performed on the most stable central 200 ms portion of the acoustic waveform. Descriptive analysis of each phonation was also conducted using sound spectrograms. Results Results showed that the complexity of phonation and the subsequent acoustic waveform is increased as transglottal airflow rate and degree of glottal adduction is manipulated in the evoked rabbit phonation model. In particular, phonatory complexity, as quantified via correlation dimension analyses and demonstrated via spectrographic characteristics, increases from “modal” (i.e., phonation elicited at just above the phonation threshold pressure) to raised intensity (phonation elicited by increasing transglottal airflow rate) to pressed (phonation elicited by increasing the stimulation current delivered to the larynx). Variations in a single dynamic dimension (airflow rate or adductory force

  18. Simplified Expert Elicitation Procedure for Risk Assessment of Operating Events

    SciTech Connect

    Ronald L. Boring; David Gertman; Jeffrey Joe; Julie Marble; William Galyean; Larry Blackwood; Harold Blackman

    2005-06-01

    This report describes a simplified, tractable, and usable procedure within the US Nuclear Regulator Commission (NRC) for seeking expert opinion and judgment. The NRC has increased efforts to document the reliability and risk of nuclear power plants (NPPs) through Probabilistic Risk Assessment (PRA) and Human Reliability Analysis (HRA) models. The Significance Determination Process (SDP) and Accident Sequence Precursor (ASP) programs at the NRC utilize expert judgment on the probability of failure, human error, and the operability of equipment in cases where otherwise insufficient operational data exist to make meaningful estimates. In the past, the SDP and ASP programs informally sought the opinion of experts inside and outside the NRC. This document represents a formal, documented procedure to take the place of informal expert elicitation. The procedures outlined in this report follow existing formal expert elicitation methodologies, but are streamlined as appropriate to the degree of accuracy required and the schedule for producing SDP and ASP analyses.

  19. Expert elicitation for a national-level volcano hazard model

    NASA Astrophysics Data System (ADS)

    Bebbington, Mark; Stirling, Mark; Cronin, Shane; Wang, Ting; Jolly, Gill

    2016-04-01

    The quantification of volcanic hazard at national level is a vital pre-requisite to placing volcanic risk on a platform that permits meaningful comparison with other hazards such as earthquakes. New Zealand has up to a dozen dangerous volcanoes, with the usual mixed degrees of knowledge concerning their temporal and spatial eruptive history. Information on the 'size' of the eruptions, be it in terms of VEI, volume or duration, is sketchy at best. These limitations and the need for a uniform approach lend themselves to a subjective hazard analysis via expert elicitation. Approximately 20 New Zealand volcanologists provided estimates for the size of the next eruption from each volcano and, conditional on this, its location, timing and duration. Opinions were likewise elicited from a control group of statisticians, seismologists and (geo)chemists, all of whom had at least heard the term 'volcano'. The opinions were combined via the Cooke classical method. We will report on the preliminary results from the exercise.

  20. Voltage transients elicited by sudden step-up of auxin

    NASA Technical Reports Server (NTRS)

    Pickard, B. G.

    1984-01-01

    It is hypothesized (i) that the molecular mechanism for the reception of friction and flexure and the mechanism by which auxin enhances ethylene production have in common a release of free calcium into the cytosol, (ii) that elevated cytosolic calcium initiates vesicle exocytosis, and (iii) that the vesicles release a factor or set of factors which depolarizes the plasmalemma and promotes ethylene synthesis. One consequence of such exocytosis should be small, extracellularly observable voltage transients. Transients, ranging in size up to 600 microvolts and possessing risetimes (10-90%) of approximately 200 ms, are known to be elicited in etiolated stems of Pisum sativum L. by friction and are here shown to be elicited by sudden increase of auxin concentration and also by a Ca2+ ionophore.