Chapter 35 Responses of monkey infero-temporal units in an orientation discrimination task

1993 ◽  
pp. 427-444 ◽  
Author(s):  
Rufin Vogels ◽  
Guy A. Orban
Keyword(s):  
Discrimination Task ◽  
Orientation Discrimination

scholarly journals Investigating the Effects of tDCS on Visual Orientation Discrimination Task Performance: “the Possible Influence of Placebo”

2019 ◽  
Vol 4 (3) ◽  
pp. 235-249
Author(s):  
A. Bin Dawood ◽  
A. Dickinson ◽  
A. Aytemur ◽  
C. Howarth ◽  
E. Milne ◽  
...  
Keyword(s):  
Placebo Effect ◽  
Discrimination Task ◽  
Low Cost ◽  
Cortical Inhibition ◽  
Orientation Discrimination ◽  
Visual Orientation ◽  
Non Invasive ◽  
Clear Link ◽  
Cortical Modulation ◽  
Improved Performance

Abstract The non-invasive neuromodulation technique tDCS offers the promise of a low-cost tool for both research and clinical applications in psychology, psychiatry, and neuroscience. However, findings regarding its efficacy are often equivocal. A key issue is that the clinical and cognitive applications studied are often complex and thus effects of tDCS are difficult to predict given its known effects on the basic underlying neurophysiology, namely alterations in cortical inhibition-excitation balance. As such, it may be beneficial to assess the effects of tDCS in tasks whose performance has a clear link to cortical inhibition-excitation balance such as the visual orientation discrimination task (ODT). In prior studies in our laboratory, no practice effects were found during 2 consecutive runs of the ODT, thus in the current investigation, to examine the effects of tDCS, subjects received 10 min of 2 mA occipital tDCS (sham, anode, cathode) between a first and second run of ODT. Surprisingly, subjects’ performance significantly improved in the second run of ODT compared to the first one regardless of the tDCS stimulation type they received (anodal, cathodal, or sham-tDCS). Possible causes for such an improvement could have been due to either a generic “placebo” effect of tDCS (as all subjects received some form of tDCS) or an increased delay period between the two runs of ODT of the current study compared to our previous work (10-min duration required to administer tDCS as opposed to ~ 2 min in previous studies as a “break”). As such, we tested these two possibilities with a subsequent experiment in which subjects received 2-min or 10-min delay between the 2 runs (with no tDCS) or 10 min of sham-tDCS. Only sham-tDCS resulted in improved performance thus these data add to a growing literature suggesting that tDCS has powerful placebo effect that may occur even in the absence of active cortical modulation.

Responses of monkey inferior temporal neurons to luminance-, motion-, and texture-defined gratings

1995 ◽  
Vol 73 (4) ◽  
pp. 1341-1354 ◽  
Author(s):  
G. Sary ◽  
R. Vogels ◽  
G. Kovacs ◽  
G. A. Orban
Keyword(s):  
Visual Perception ◽  
Relative Motion ◽  
Discrimination Task ◽  
Stimulus Presentation ◽  
Response Strength ◽  
The Other ◽  
Orientation Discrimination ◽  
Macaque Monkeys ◽  
Tuning Width ◽  
Visual Cortical

1. We recorded from neurons responsive to gratings in the inferior temporal (IT) cortices of macaque monkeys. One of the monkeys performed an orientation discrimination task; the other maintained fixation during stimulus presentation. Stimuli consisted of gratings based on discontinuities in luminance, relative motion, and texture. 2. IT cells responded well to gratings defined solely by relative motion, implying either direct or indirect motion input into IT, an area that is part of the ventral visual cortical pathway. 3. Response strength in general did not depend on the cue used to define the gratings. Latency values observed for the two static grating types (luminance- and texture-defined gratings) were similar, but significantly shorter than those measured for the kinetic gratings. 4. Stimulus orientation had a significant effect in 27%, 27%, and 9% of the cells tested with luminance-, kinetic-, and texture-defined gratings, respectively. 5. Only a small proportion of cells were orientation sensitive for more than one defining cue. The average preferred orientation for luminance and kinetic gratings matched; the tuning width was similar for the two cues. 6. Our results indicate that IT cells may contribute to cue-invariant coding of boundaries and edges. We discuss the relevance of these results to visual perception.

scholarly journals Human-like perceptual masking is difficult to observe in rats performing an orientation discrimination task

PLoS ONE ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. e0207179 ◽  
Author(s):  
Katrina Louise Dell ◽  
Ehsan Arabzadeh ◽  
Nicholas Seow Chiang Price
Keyword(s):  
Discrimination Task ◽  
Orientation Discrimination ◽  
Perceptual Masking

scholarly journals A Sparse Unreliable Distributed Code Underlies the Limits of Behavioral Discrimination

2018 ◽  
Author(s):  
Balaji Sriram ◽  
Alberto Cruz-Martin ◽  
Lillian Li ◽  
Pamela Reinagel ◽  
Anirvan Ghosh
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Single Unit ◽  
Discrimination Task ◽  
Orientation Discrimination ◽  
Behavioral Performance ◽  
High Contrast ◽  
The World ◽  
Mouse Visual Cortex ◽  
Linear Decoding

ABSTRACTThe cortical code that underlies perception must enable subjects to perceive the world at timescales relevant for behavior. We find that mice can integrate visual stimuli very quickly (<100 ms) to reach plateau performance in an orientation discrimination task. To define features of cortical activity that underlie performance at these timescales, we measured single unit responses in the mouse visual cortex at timescales relevant to this task. In contrast to high contrast stimuli of longer duration, which elicit reliable activity in individual neurons, stimuli at the threshold of perception elicit extremely sparse and unreliable responses in V1 such that the activity of individual neurons do not reliably report orientation. Integrating information across neurons, however, quickly improves performance. Using a linear decoding model, we estimate that integrating information over 50-100 neurons is sufficient to account for behavioral performance. Thus, at the limits of perception the visual system is able to integrate information across a relatively small number of highly unreliable single units to generate reliable behavior.

scholarly journals Choice-Related Activity during Visual Slant Discrimination in Macaque CIP but Not V3A

2018 ◽  
Author(s):  
L. Caitlin Elmore ◽  
Ari Rosenberg ◽  
Gregory C. DeAngelis ◽  
Dora E. Angelaki
Keyword(s):  
Visual Processing ◽  
Discrimination Task ◽  
Three Dimensional ◽  
Surface Orientation ◽  
Orientation Discrimination ◽  
Visual Orientation ◽  
Planar Surface ◽  
Related Activity ◽  
Planar Surfaces ◽  
3D Surface

AbstractCreating three-dimensional (3D) representations of the world from two-dimensional retinal images is fundamental to many visual guided behaviors including reaching and grasping. A critical component of this process is determining the 3D orientation of objects. Previous studies have shown that neurons in the caudal intraparietal area (CIP) of the macaque monkey represent 3D planar surface orientation (i.e., slant and tilt). Here we compare the responses of neurons in areas V3A (which is implicated in 3D visual processing and which precedes CIP in the visual hierarchy) and CIP to 3D oriented planar surfaces. We then examine whether activity in these areas correlates with perception during a fine slant discrimination task in which monkeys report if the top of a surface is slanted towards or away from them. Although we find that V3A and CIP neurons show similar sensitivity to planar surface orientation, significant choice-related activity during the slant discrimination task is rare in V3A but prominent in CIP. These results implicate both V3A and CIP in the representation of 3D surface orientation, and suggest a functional dissociation between the areas based on slant-related decision signals.Significance StatementSurface orientation perception is fundamental to visually guided behaviors such as reaching, grasping, and navigation. Previous studies implicate the caudal intraparietal area (CIP) in the representation of 3D surface orientation. Here we show that responses to 3D oriented planar surfaces are similar in CIP and V3A, which precedes CIP in the cortical hierarchy. However, we also find a qualitative distinction between the two areas: only CIP neurons show robust choice-related activity during a fine visual orientation discrimination task.

scholarly journals Interfering with a memory without erasing its trace

2019 ◽  
Author(s):  
Gesa Lange ◽  
Mario Senden ◽  
Alexandra Radermacher ◽  
Peter De Weerd
Keyword(s):  
Discrimination Task ◽  
Orientation Discrimination ◽  
Memory Mechanism ◽  
Open Questions ◽  
Model Predictions ◽  
Task Training ◽  
Human Participants ◽  
Similar Task ◽  
Training Protocol

AbstractPrevious research has shown that performance of a novice skill can be easily interfered with by subsequent training of another skill. We address the open questions whether extensively trained skills show the same vulnerability to interference as novice skills and which memory mechanism regulates interference between expert skills. We developed a recurrent neural network model of V1 able to learn from feedback experienced over the course of a long-term orientation discrimination experiment. After first exposing the model to one discrimination task for 3480 consecutive trials, we assessed how its performance was affected by subsequent training in a second, similar task. Training the second task strongly interfered with the first (highly trained) discrimination skill. The magnitude of interference depended on the relative amounts of training devoted to the different tasks. We used these and other model outcomes as predictions for a perceptual learning experiment in which human participants underwent the same training protocol as our model. Specifically, over the course of three months participants underwent baseline training in one orientation discrimination task for 15 sessions before being trained for 15 sessions on a similar task and finally undergoing another 15 sessions of training on the first task (to assess interference). Across all conditions, the pattern of interference observed empirically closely matched model predictions. According to our model, behavioral interference can be explained by antagonistic changes in neuronal tuning induced by the two tasks. Remarkably, this did not stem from erasing connections due to earlier learning but rather from a reweighting of lateral inhibition.

Surface Orientation Discrimination Activates Caudal and Anterior Intraparietal Sulcus in Humans: An Event-Related fMRI Study

2001 ◽  
Vol 85 (3) ◽  
pp. 1309-1314 ◽  
Author(s):  
Elisa Shikata ◽  
Farsin Hamzei ◽  
Volkmar Glauche ◽  
René Knab ◽  
Christian Dettmers ◽  
...  
Keyword(s):  
Discrimination Task ◽  
Parietal Lobe ◽  
Functional Neuroimaging ◽  
3D Structure ◽  
Color Discrimination ◽  
Surface Orientation ◽  
Linear Perspective ◽  
Orientation Discrimination ◽  
Intraparietal Sulcus ◽  
Functional Neuroanatomy

Perception of surface orientation is an essential step for the reconstruction of the three-dimensional (3D) structure of an object. Human lesion and functional neuroimaging studies have demonstrated the importance of the parietal lobe in this task. In primate single-unit studies, neurons in the caudal part of the intraparietal sulcus (CIP) were found to be active during the extraction of surface orientation through monocular (two-dimensional) cues such as texture gradients and linear perspective as well as binocular (3D) cues such as disparity gradient and orientation disparity. We used event-related fMRI to study the functional neuroanatomy of surface orientation discrimination using stimuli with monocular depth cues in six volunteers. Both posterior (CIP) and anterior (AIP) areas within the intraparietal sulcus showed a stronger activation during surface orientation as compared with a control (color discrimination) task using identical stimuli. Furthermore, the signal changes in CIP showed a greater performance effect than those in AIP, suggesting that CIP is tightly linked to the discrimination task.

Bayesian Computation in Recurrent Neural Circuits

2004 ◽  
Vol 16 (1) ◽  
pp. 1-38 ◽  
Author(s):  
Rajesh P. N. Rao
Keyword(s):  
Motion Detection ◽  
Network Architecture ◽  
Discrimination Task ◽  
Visual Motion ◽  
Natural World ◽  
Direction Selectivity ◽  
Orientation Discrimination ◽  
Posterior Probabilities ◽  
Motion Direction ◽  
Model Network

A large number of human psychophysical results have been successfully explained in recent years using Bayesian models. However, the neural implementation of such models remains largely unclear. In this article, we show that a network architecture commonly used to model the cerebral cortex can implement Bayesian inference for an arbitrary hidden Markov model. We illustrate the approach using an orientation discrimination task and a visual motion detection task. In the case of orientation discrimination, we show that the model network can infer the posterior distribution over orientations and correctly estimate stimulus orientation in the presence of significant noise. In the case of motion detection, we show that the resulting model network exhibits direction selectivity and correctly computes the posterior probabilities over motion direction and position. When used to solve the well-known random dots motion discrimination task, the model generates responses that mimic the activities of evidence-accumulating neurons in cortical areas LIP and FEF. The framework we introduce posits a new interpretation of cortical activities in terms of log posterior probabilities of stimuli occurring in the natural world.

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