Psychophysical Results Research Articles

Forward Masking in the Amplitude-Modulation Domain for Tone Carriers: Psychophysical Results and Physiological Correlates

Wojtczak and Viemeister (J Acoust Soc Am 118:3198-3210, 2005) demonstrated forward masking in the amplitude-modulation (AM) domain. The present study examined whether this effect has correlates in physiological responses to AM at the level of the auditory midbrain. The human psychophysical experiment used 40-Hz, 100% AM (masker AM) that was imposed on a 5.5-kHz carrier during the first 150ms of its duration. The masker AM was followed by a 50-ms burst of AM of the same rate (signal AM) imposed on the same (uninterrupted) carrier, either immediately after the masker or with a delay. In the physiological experiment, single-unit extracellular recordings in the awake rabbit inferior colliculus (IC) were obtained for stimuli designed to be similar to the uninterrupted-carrier conditions used in the psychophysics. The masker AM was longer (500ms compared with 150ms in the psychophysical experiment), and the carrier and modulation rate were chosen based on each neuron's audio- and envelope-frequency selectivity. Based on the average discharge rates of the responses or on the temporal correlation between neural responses to masked and unmasked stimuli, only a small subset of the population of IC cells exhibited suppression of signal AM following the masker. In contrast, changes in the discharge rates between the temporal segments of the carrier immediately preceding the signal AM and during the signal AM varied as a function of masker-signal delay with a trend that matched the psychophysical results. Unless the physiological observations were caused by species differences, they suggest that stages of processing higher than the IC must be considered to account for the AM-processing time constants measured perceptually in humans.

Fragment-Based Learning of Visual Object Categories in Non-Human Primates

When we perceive a visual object, we implicitly or explicitly associate it with an object category we know. Recent research has shown that the visual system can use local, informative image fragments of a given object, rather than the whole object, to classify it into a familiar category. We have previously reported, using human psychophysical studies, that when subjects learn new object categories using whole objects, they incidentally learn informative fragments, even when not required to do so. However, the neuronal mechanisms by which we acquire and use informative fragments, as well as category knowledge itself, have remained unclear. Here we describe the methods by which we adapted the relevant human psychophysical methods to awake, behaving monkeys and replicated key previous psychophysical results. This establishes awake, behaving monkeys as a useful system for future neurophysiological studies not only of informative fragments in particular, but also of object categorization and category learning in general.

Macaque ganglion cell responses to probe stimuli on modulated backgrounds.

In the natural environment, visual targets have to be detected and identified on changing backgrounds. Here, responses of parasol (magnocellular) ganglion cells to probes on modulated backgrounds are described. At low frequency, the adaptation level of the background influences the probe response, but with increasing frequency there is a strong interaction with the response to the background per se, so that on- and off-center cell responses are modulated in different phases. Interactions with the background response include both thresholding effects (when the cell's firing is suppressed and no pulse response occurs) and saturation effects (when the background response is vigorous the pulse generates few additional spikes). At 30 Hz, the effect of the pulse is largely a suppression or phase shift of the background response. The data are relevant to the probed-sinewave paradigm, in which pulse detection thresholds are modulated with pulse phase relative to a sinusoidal background. The physiological substrates of the psychophysical results with the probed-sinewave paradigm appear complex, with on- and off-center cells likely to contribute to detection at different pulse phases.

The course of olfactory deficits in patients with Parkinson's disease—A study based on psychophysical and electrophysiological measures

Objectives Patients with Parkinson's disease (PD) commonly show olfactory deficits in the early stages of the disease. These deficits can be verified psychophysically or electrophysiologically using olfactory event-related potentials (OERP). While psychophysical olfactory function in PD patients can improve over time, the course of OERPs in PD has not yet been investigated. Methods Olfactory function was investigated twice in 19 patients at 5-year intervals. Psychophysical tests included the “Sniffin’ Sticks” test battery. In addition, OERPs were recorded in response to two odors on each side (phenyl-ethyl-alcohol: 40% (v/v), H 2S, 6 ppm). OERPs were evaluated regarding existence (yes/no). Average disease duration at follow-up was 9.0 years and the average Hoehn and Yahr score (disease stage) was 2.2. Results Psychophysically, 1 patient was normosmic, 14 were hyposmic, and 4 were functionally anosmic at the initial visit. Re-examination revealed 1 normosmic, 9 hyposmic, and 8 functionally anosmic patients. Mean olfactory function decreased significantly in all patients. OERPs were initially existent in 3 out of 19 patients. At follow-up, OERPs were no longer present in these patients, but were detectable in 3 other patients. Conclusions Overall, mean olfactory function decreased, although improvements were observed at the individual level. We confirmed previous findings regarding psychophysical follow-up results. Electrophysiological measures showed a pattern of fluctuation in olfactory function comparable to that of the psychophysical results. These fluctuations do not seem to predict the course of the disease.

Ensemble of local and global information for finger–knuckle-print recognition

Biometrics authentication is an effective method for automatically recognizing a person's identity. Recently, it has been found that the finger-knuckle-print (FKP), which refers to the inherent skin patterns of the outer surface around the phalangeal joint of one's finger, has high capability to discriminate different individuals, making it an emerging biometric identifier. In this paper, based on the results of psychophysics and neurophysiology studies that both local and global information is crucial for the image perception, we present an effective FKP recognition scheme by extracting and assembling local and global features of FKP images. Specifically, the orientation information extracted by the Gabor filters is coded as the local feature. By increasing the scale of Gabor filters to infinite, actually we can get the Fourier transform of the image, and hence the Fourier transform coefficients of the image can be taken as the global features. Such kinds of local and global features are naturally linked via the framework of time-frequency analysis. The proposed scheme exploits both local and global information for the FKP verification, where global information is also utilized to refine the alignment of FKP images in matching. The final matching distance of two FKPs is a weighted average of local and global matching distances. The experimental results conducted on our FKP database demonstrate that the proposed local-global information combination scheme could significantly improve the recognition accuracy obtained by either local or global information and lead to promising performance of an FKP-based personal authentication system.

Vision: Keeping the World Still When the Eyes Move

A long-standing problem for visual science is how the world remains so apparently stable in the face of continual rapid eye movements. New experimental evidence, and computational models are helping to solve this mystery.

Horizontal and vertical noise tolerance of binocular correlation in random dot stereograms

Although our eyes are separated horizontally and binocular disparities are therefore mainly horizontal, binocular correlation tolerates substantial vertical disparities. To study the size of the vertical disparity range for binocular correlation, we measured the tolerance for both horizontal and vertical disparity noise, in detecting sinusoidal depth gratings in random dot patterns. We used dense, dynamic random dot stereograms and Gaussian distributed disparity noise. Trials consisted of two 0.8 s intervals, one containing the depth corrugation (stimulus), the other containing the same disparity values randomly distributed across the window (reference). For different grating parameters tolerance for vertical disparity noise was at least as large as for horizontal disparity noise. Moreover, the effects of horizontal and vertical noise added linearly, suggesting a horizontal-vertical isotropy. To find out whether these resultss indeed reflect the size of horizontal and vertical ranges for resolvable disparities, we performed a parametric model analysis for binocular correlation. The model was presented with random dot stereograms of sinusoidal depth gratings, similar to those in the psychophysical measurements, and solved the correspondence problem by determining all possible matches of a pixel in one eye within an ellipsoid correlation area around the corresponding point in the other eye. An arbitrary, but highly efficient algorithm determined whether the stimulus or reference presentation provided the best match to a sinusoidal depth corrugation. A comparison of horizontal and vertical noise tolerance for the human observer and for the model revealed upper and lower limits for the vertical disparity range. However, psychophysical results could be reproduced with different combinations of horizontal and vertical disparity range, and therefore do not reflect a low level horizontal-vertical isotropy for binocular correlation.

Comparing image quality of print-on-demand books and photobooks from web-based vendors

Because of the emergence of e-commerce and developments in print engines designed for economical output of very short runs, there are increased business opportunities and consumer options for print-on-demand books and photobooks. The current state of these printing modes allows for direct uploading of book files via the web, printing on nonoffset printers, and distributing by standard parcel or mail delivery services. The goal of this research is to assess the image quality of print-on-demand books and photobooks produced by various Web-based vendors and to identify correlations between psychophysical results and objective metrics. Six vendors were identified for one-off (single-copy) print-on-demand books, and seven vendors were identified for photobooks. Participants rank ordered overall quality of a subset of individual pages from each book, where the pages included text, photographs, or a combination of the two. Observers also reported overall quality ratings and price estimates for the bound books. Objective metrics of color gamut, color accuracy, accuracy of International Color Consortium profile usage, eye-weighted root mean square L*, and cascaded modulation transfer acutance were obtained and compared to the observer responses. We introduce some new methods for normalizing data as well as for strengthening the statistical significance of the results. Our approach includes the use of latent mixed-effect models. We found statistically significant correlation with overall image quality and some of the spatial metrics, but correlations between psychophysical results and other objective metrics were weak or nonexistent. Strong correlation was found between psychophysical results of overall quality assessment and estimated price associated with quality. The photobook set of vendors reached higher image-quality ratings than the set of print-on-demand vendors. However, the photobook set had higher image-quality variability.

Motion and reverse-phi stimuli that do not drive standard Fourier or non-Fourier motion mechanisms

Event Abstract Back to Event Motion and reverse-phi stimuli that do not drive standard Fourier or non-Fourier motion mechanisms Qin Hu1* and Jonathan Victor1 1 Weill Cornell Medical College, United States Detection of motion is a crucial component of visual processing, and is generally considered to consist of two stages: an early stage in which local motion is extracted and a later stage at which local motion signals are combined into object motion or flows. Early motion processing is generally considered to be carried out by first-order (Fourier) and second-order (non-Fourier) mechanisms. Fourier motion mechanisms extract motion when the pairwise spatiotemporal correlation of luminance signal is present. Non-Fourier mechanisms are thought to work via local nonlinear pre-processing, such as flicker detection or extraction of unsigned contrast, followed by a spatiotemporal correlation of the resulting signals. To probe the computations underlying motion perception, we created a new class of non-Fourier motion stimuli: binary movies characterized by their 3rd- and 4th-order spatiotemporal correlations. As with other non-Fourier stimuli, they lack second-order correlations, and therefore their motion cannot be detected by standard Fourier mechanisms. Additionally, these stimuli lack pairwise spatiotemporal correlation of edges or flicker - and thus, also cannot be detected by extraction of one of these features, followed by standard motion analysis. Nevertheless, our psychophysical results showed that many of these stimuli produced apparent motion in human observers. The pattern of responses - i.e., which specific spatiotemporal correlations led to a percept of motion - was highly consistent across subjects. Moreover, for many of these stimuli, inverting the overall contrast of the stimulus reversed the direction of apparent motion. This "reverse phi" phenomenon, as well as the high-order-only spatiotemporal correlation of the stimulus, challenge existing models, including models that correlate low-level features (e.g., the Reichardt model and spatiotemporal energy models) and gradient models. Simple augmentations of those models - for example, spatiotemporal filters followed by non-quadratic nonlinearities - can account for some aspects of the percepts, but not for others. This suggests that a full account of motion percepts driven by high-order spatiotemporal correlations will lead to a more complete understanding of the computations underlying early motion processing. Conference: Computational and Systems Neuroscience 2010, Salt Lake City, UT, United States, 25 Feb - 2 Mar, 2010. Presentation Type: Poster Presentation Topic: Poster session III Citation: Hu Q and Victor J (2010). Motion and reverse-phi stimuli that do not drive standard Fourier or non-Fourier motion mechanisms. Front. Neurosci. Conference Abstract: Computational and Systems Neuroscience 2010. doi: 10.3389/conf.fnins.2010.03.00311 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 08 Mar 2010; Published Online: 08 Mar 2010. * Correspondence: Qin Hu, Weill Cornell Medical College, New York, United States, qih2002@med.cornell.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Qin Hu Jonathan Victor Google Qin Hu Jonathan Victor Google Scholar Qin Hu Jonathan Victor PubMed Qin Hu Jonathan Victor Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Plasticity of multisensory dorsal stream functions: Evidence from congenitally blind and sighted adults

The dorsal stream has been proposed to compute vision for space perception and for the control of action. However, perceiving space and guiding movements is not only based on vision but also on other sensory modalities such as proprioception and kinesthesia. Blind people who lost vision early in life provide an exceptional example to study the plasticity of dorsal stream functions. Using fMRI and psychophysical methods, action control and space perception was investigated in congenitally blind and sighted adults while performing active and passive hand movements without visual feedback. The functional imaging data showed largely overlapping activation patterns for kinesthetically guided hand movements in congenitally blind and sighted participants covering regions of the dorsal stream. In contrast to the sighted participants, congenitally blind participants additionally activated the extrastriate cortex and the auditory cortex. The psychophysical results revealed a significant correlation between proprioceptive spatial discrimination acuity of the blind and the age when they had attended an orientation and mobility training, i.e., an extensive non-visual spatial training. The earlier the blind acquired such a spatial training the more accurate and the more precise was their space perception in later life. Our findings suggest a multisensory network of movement control that develops on the basis of sensorimotor feedback rather than being under the exclusive control of vision. Thus, visual deprivation seems to result in both cross-modal and compensatory intra-modal plasticity. The present findings further imply that dorsal stream functions are shaped by non-visual spatial information during early development.

画像の極値点情報に基づく誘目領域の推定

Estimating the salient regions of an image plays a key role in scene analysis and image understanding. We can also apply saliency-based image processing techniques to image compression, evaluation, and effective searching methods. One of the most difficult problems is estimating the regions before recognizing what is in the image -- a problem that can be solved by accessing information of the low-level structures of objects in the image. This paper describes a method for estimating salient regions in images based on the distribution stability of local extrema of luminance during image blurring. Under blurring conditions, if an object's region has a more stable structure compared to another area, it must be more salient, so the saliency of these regions must be defined based on their stability for blurring. In the developed method, the local extrema of images are used to describe the complexity of the image's objects and background. Salient regions are estimated based on the stability of the local extrema for the blurring parameter. Experiments were conducted to compare the estimated result of salient regions and the psychophysical result obtained from the analysis of eye movement recordings. Results show that our method successfully extracts salient regions of natural images.

Adaptive gain modulation in V1 explains contextual modifications during bisection learning.

The neuronal processing of visual stimuli in primary visual cortex (V1) can be modified by perceptual training. Training in bisection discrimination, for instance, changes the contextual interactions in V1 elicited by parallel lines. Before training, two parallel lines inhibit their individual V1-responses. After bisection training, inhibition turns into non-symmetric excitation while performing the bisection task. Yet, the receptive field of the V1 neurons evaluated by a single line does not change during task performance. We present a model of recurrent processing in V1 where the neuronal gain can be modulated by a global attentional signal. Perceptual learning mainly consists in strengthening this attentional signal, leading to a more effective gain modulation. The model reproduces both the psychophysical results on bisection learning and the modified contextual interactions observed in V1 during task performance. It makes several predictions, for instance that imagery training should improve the performance, or that a slight stimulus wiggling can strongly affect the representation in V1 while performing the task. We conclude that strengthening a top-down induced gain increase can explain perceptual learning, and that this top-down signal can modify lateral interactions within V1, without significantly changing the classical receptive field of V1 neurons.

Neural and Behavioral Discrimination of Sound Duration by Cats

Sound duration is important for distinguishing auditory object. Previous studies on the neural representation of duration have usually lacked psychophysical data obtained from the same species; hence, the correspondence between neural and behavioral discrimination of duration remains obscure. We addressed this issue in cats by using the signal detection theory to investigate both neural activities in the primary auditory cortex (A1) and the cat's behavioral performance. We found that 320 ms duration can be well discriminated from 10 ms duration by some A1 neurons with specific response patterns: sustained response extended proportionally with the increase of stimulus duration and the On-Off response synchronizing stimulus onset and offset. Neurons with only On response cannot discriminate duration. The discrimination performance of both sustained and On-Off responses deteriorated as the target duration decreased from 320 to 20 ms and the percentage of discriminative neurons (correct rate >0.75) decreased from 40 to 2%. Compared with the psychophysical results, we found that the psychometric functions of cats well matched the neurometric functions of most sustained-response neurons and a small number of On-Off-response neurons. Pooling the spikes of multiple units improved neural discrimination, which may be attributable to the salience (noise reduction) of the responses in pooled data. Our results suggest that the sustained and Off responses of A1 neurons underlie the duration discrimination behavior of cats.

Two Routes to Face Perception: Evidence From Psychophysics and Computational Modeling

The aim of this study was to separately analyze the role of featural and configural face representations. Stimuli containing only featural information were created by cutting the faces into their parts and scrambling them. Stimuli only containing configural information were created by blurring the faces. Employing an old-new recognition task, the aim of Experiments 1 and 2 was to investigate whether unfamiliar faces (Exp. 1) or familiar faces (Exp. 2) can be recognized if only featural or configural information is provided. Both scrambled and blurred faces could be recognized above chance level. A further aim of Experiments 1 and 2 was to investigate whether our method of creating configural and featural stimuli is valid. Pre-activation of one form of representation did not facilitate recognition of the other, neither for unfamiliar faces (Exp. 1) nor for familiar faces (Exp. 2). This indicates a high internal validity of our method for creating configural and featural face stimuli. Experiment 3 examined whether features placed in their correct categorical relational position but with distorted metrical distances facilitated recognition of unfamiliar faces. These faces were recognized no better than the scrambled faces in Experiment 1, providing further evidence that facial features are stored independently of configural information. From these results we conclude that both featural and configural information are important to recognize a face and argue for a dual-mode hypothesis of face processing. Using the psychophysical results as motivation, we propose a computational framework that implements featural and configural processing routes using an appearance-based representation based on local features and their spatial relations. In three computational experiments (Experiments 4-6) using the same sets of stimuli, we show how this framework is able to model the psychophysical data.

A model of encoding and decoding in V1 and MT accounts for motion perception anisotropies in the human visual system

We used the motion aftereffect (MAE) to psychophysically characterize tuning of motion perception in the human visual system. The function relating MAE strength and the range of directions present in the adapter stimulus provides information regarding the width of direction tuning of motion adaptation. We compared the directional anisotropy in MAE tuning width to the well-known oblique effect in motion direction discrimination. In agreement with previous research, we found that subjects had lower motion direction discrimination thresholds for cardinal compared to oblique directions. For each subject, we also estimated MAE tuning width for a cardinal and an oblique direction by measuring the strength of the MAE for adapter stimuli containing different directional variances. The MAE tuning width was smaller for the cardinal direction, suggesting a fundamental similarity between motion direction discrimination and tuning of the MAE. We constructed a model of encoding of motion stimuli by V1 and MT and decoding of stimulus information from the cells in area MT. The model includes an anisotropy in the representation of different directions of motion in area V1. As a consequence of the connections implemented in the model, this anisotropy propagates to cells in MT. Model simulations predicted an oblique effect for both direction discrimination thresholds and MAE tuning width, consistent with our experimental results. The model also concurs with a recent report that the magnitude of the oblique effect for direction discrimination is inversely proportional to the directional variance of the stimulus. The agreement between model predictions and empirical data was obtained only when the model employed a maximum likelihood decoding algorithm. Alternative decoding mechanisms such as vector averaging and winner-take-all failed to account for the psychophysical results.

The visual perception of human and animal motion in point-light displays

Mounting neurophysiological evidence indicates that the visual analysis of human movement differs from the visual analysis of other categories of complex movement. If different patterns of neural activity underlie visual percepts of human and nonhuman movement, then psychophysical measures should elucidate different patterns of visual sensitivity to human movement and similarly complex, but nonhuman movement. To test this prediction, two psychophysical studies compared visual sensitivity to human and animal motions. Using a simultaneous masking paradigm, observers performed a coherent motion detection task with point-light displays of human and horse gait, presented upright and inverted. While task performance indicated the use of configural processing during the detection of both human and horse motion, observers demonstrated greater visual sensitivity to coherent human motion than coherent horse motion. Recent experience influenced orientation dependence for both types of motion. Together with previous neurophysiological findings, these psychophysical results suggest that the visual perception of human movement is both distinct from and shares commonalities with the visual perception of similarly complex, nonhuman movement.

Two contrast adaptation processes: Contrast normalization and shifting, rectifying contrast comparison

We present psychophysical results demonstrating the interaction of two contrast adaptation processes in human vision: (1) A contrast-gain-control process of the normalization type and (2) a recently-discovered shifting, rectifying contrast-comparison process. Observers adapted (for 1 s) to a grid of Gabor patches at one contrast, then a brief (94 ms) test pattern was shown, and then the adapt pattern was shown again (1 s). The test pattern was the same as the adapt pattern except that the Gabor patches had two different contrasts arranged to create vertical or horizontal contrast-defined stripes. Observers identified the orientation of the test pattern's stripes. Performance is a complicated ("butterfly shaped") function of the average test contrast, centered at the adapt contrast. This shape is a consequence of the interaction of the two contrast adaptation processes. At the ends of the function are "Weber zones" in which the contrast-gain-control process dominates, and at the center of the function is a "Buffy zone" in which the recently-discovered contrast-comparison process dominates.

Perceptual Incongruence Influences Bistability and Cortical Activation

We employed a parametric psychophysical design in combination with functional imaging to examine the influence of metric changes in perceptual incongruence on perceptual alternation rates and cortical responses. Subjects viewed a bistable stimulus defined by incongruent depth cues; bistability resulted from incongruence between binocular disparity and monocular perspective cues that specify different slants (slant rivalry). Psychophysical results revealed that perceptual alternation rates were positively correlated with the degree of perceived incongruence. Functional imaging revealed systematic increases in activity that paralleled the psychophysical results within anterior intraparietal sulcus, prior to the onset of perceptual alternations. We suggest that this cortical activity predicts the frequency of subsequent alternations, implying a putative causal role for these areas in initiating bistable perception. In contrast, areas implicated in form and depth processing (LOC and V3A) were sensitive to the degree of slant, but failed to show increases in activity when these cues were in conflict.

Computational Neuroscience Approach to Attention, Memory, and Decision-Making

Event Abstract Back to Event Computational Neuroscience Approach to Attention, Memory, and Decision-Making Gustavo Deco1* 1 Universitat Pompeu Fabra, Institucio Catalana de Recerca i Estudis Avançats (ICREA), Spain Cognitive behaviour requires complex context-dependent processing of information that emerges from the links between attentional perceptual processes, working memory and reward-based evaluation of the performed actions. We describe a computational neuroscience theoretical framework, which shows how an attentional state held in a short-term memory in the prefrontal cortex can by top-down processing influence ventral and dorsal stream cortical areas using biased competition to account for many aspects of visual attention. We also show how within the prefrontal cortex an attentional bias can influence the mapping of sensory inputs to motor outputs, and thus play an important role in decision-making. We also show how the absence of expected rewards can switch the attentional bias signal, and thus rapidly and flexibly alter cognitive performance. This theoretical framework incorporates spiking and synaptic dynamics, which enable single neuron responses, fMRI activations, psychophysical results, the effects of pharmacological agents, and the effects of damage to parts of the system, to be explicitly simulated and predicted. This computational neuroscience framework provides an approach for integrating different levels of investigation of brain function, and for and top-down processes interact in visual cognition, and show how some apparently serial processes reflect the operation of interacting parallel distributed systems. Conference: 3rd Mediterranean Conference of Neuroscience , Alexandria, Egypt, 13 Dec - 16 Dec, 2009. Presentation Type: Oral Presentation Topic: Symposium 01 – Neural dynamics, learning and functional recovery Citation: Deco G (2009). Computational Neuroscience Approach to Attention, Memory, and Decision-Making. Front. Neurosci. Conference Abstract: 3rd Mediterranean Conference of Neuroscience . doi: 10.3389/conf.neuro.01.2009.16.006 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Nov 2009; Published Online: 18 Nov 2009. * Correspondence: Gustavo Deco, Universitat Pompeu Fabra, Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain, gustavo.deco@upf.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gustavo Deco Google Gustavo Deco Google Scholar Gustavo Deco PubMed Gustavo Deco Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

A Computational Neuroscience Approach to Attention, Memory, and Decision – Making

Event Abstract Back to Event A Computational Neuroscience Approach to Attention, Memory, and Decision – Making Gustavo Deco1* 1 Universitat Pompeu Fabra; Passeig de Circumval.lacio, Institucio Catalana de Recerca i Estudis Avançats (ICREA), Spain Cognitive behaviour requires complex context-dependent processing of information that emerges from the links between attentional perceptual processes, working memory and reward-based evaluation of the performed actions. We describe a computational neuroscience theoretical framework, which shows how an attentional state held in a short-term memory in the prefrontal cortex can by top-down processing influence ventral and dorsal stream cortical areas using biased competition to account for many aspects of visual attention. We also show how within the prefrontal cortex an attentional bias can influence the mapping of sensory inputs to motor outputs, and thus play an important role in decision-making. We also show how the absence of expected rewards can switch the attentional bias signal, and thus rapidly and flexibly alter cognitive performance. This theoretical framework incorporates spiking and synaptic dynamics, which enable single neuron responses, fMRI activations, psychophysical results, the effects of pharmacological agents, and the effects of damage to parts of the system, to be explicitly simulated and predicted. This computational neuroscience framework provides an approach for integrating different levels of investigation of brain function, and for and top-down processes interact in visual cognition, and show how some apparently serial processes reflect the operation of interacting parallel distributed systems. Conference: 3rd Mediterranean Conference of Neuroscience , Alexandria, Egypt, 13 Dec - 16 Dec, 2009. Presentation Type: Oral Presentation Topic: Plenary lectures Citation: Deco G (2009). A Computational Neuroscience Approach to Attention, Memory, and Decision – Making. Front. Neurosci. Conference Abstract: 3rd Mediterranean Conference of Neuroscience . doi: 10.3389/conf.neuro.01.2009.16.004 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Nov 2009; Published Online: 18 Nov 2009. * Correspondence: Gustavo Deco, Universitat Pompeu Fabra; Passeig de Circumval.lacio, Institucio Catalana de Recerca i Estudis Avançats (ICREA), 8 – 08003 Barcelona, Spain, gustavo.deco@upf.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gustavo Deco Google Gustavo Deco Google Scholar Gustavo Deco PubMed Gustavo Deco Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.