@article {88, title = {Fast Readout of Object Identity from Macaque Inferior Temporal Cortex}, journal = {Science}, volume = {310}, year = {2005}, month = {04/2005}, pages = {863 - 866}, abstract = {

Understanding the brain computations leading to object recognition requires quantitative characterization of the information represented in inferior temporal (IT) cortex. We used a biologically plausible, classifier-based readout technique to investigate the neural coding of selectivity and invariance at the IT population level. The activity of small neuronal populations (approximately 100 randomly selected cells) over very short time intervals (as small as 12.5 milliseconds) contained unexpectedly accurate and robust information about both object \"identity\" and \"category.\" This information generalized over a range of object positions and scales, even for novel objects. Coarse information about position and scale could also be read out from the same population.

}, keywords = {Action Potentials, Animals, Brain Mapping, Macaca mulatta, Neurons, Psychology, Psychomotor Performance, Recognition, Temporal Lobe, Time Factors, Visual Perception}, issn = {0036-8075}, doi = {10.1126/science.1117593}, url = {https://www.sciencemag.org/lookup/doi/10.1126/science.1117593}, author = {Hung, Chou P. and Kreiman, Gabriel and Poggio, Tomaso and DiCarlo, James J.} } @article {87, title = {Multiple Object Response Normalization in Monkey Inferotemporal Cortex}, journal = {Journal of Neuroscience}, volume = {25}, year = {2005}, month = {07/2005}, pages = {8150 - 8164}, abstract = {

The highest stages of the visual ventral pathway are commonly assumed to provide robust representation of object identity by disregarding confounding factors such as object position, size, illumination, and the presence of other objects (clutter). However, whereas neuronal responses in monkey inferotemporal cortex (IT) can show robust tolerance to position and size changes, previous work shows that responses to preferred objects are usually reduced by the presence of nonpreferred objects. More broadly, we do not yet understand multiple object representation in IT. In this study, we systematically examined IT responses to pairs and triplets of objects in three passively viewing monkeys across a broad range of object effectiveness. We found that, at least under these limited clutter conditions, a large fraction of the response of each IT neuron to multiple objects is reliably predicted as the average of its responses to the constituent objects in isolation. That is, multiple object responses depend primarily on the relative effectiveness of the constituent objects, regardless of object identity. This average effect becomes virtually perfect when populations of IT neurons are pooled. Furthermore, the average effect cannot simply be explained by attentional shifts but behaves as a primarily feedforward response property. Together, our observations are most consistent with mechanistic models in which IT neuronal outputs are normalized by summed synaptic drive into IT or spiking activity within IT and suggest that normalization mechanisms previously revealed at earlier visual areas are operating throughout the ventral visual stream.

}, keywords = {Animals, Brain Mapping, Macaca mulatta, Male, Photic Stimulation, Posture, Psychology, Recognition, Temporal Lobe, Visual Pathways, Visual Perception}, issn = {0270-6474}, doi = {10.1523/JNEUROSCI.2058-05.2005}, url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.2058-05.2005}, author = {Zoccolan, D. and Cox, David D. and DiCarlo, James J.} } @article {105, title = {Form representation in monkey inferotemporal cortex is virtually unaltered by free viewing}, journal = {Nature Neuroscience}, volume = {3}, year = {2000}, month = {01/2000}, pages = {814 - 821}, abstract = {

How are objects represented in the brain during natural behavior? Visual object recognition in primates is thought to depend on the inferotemporal cortex {(IT).} In most neurophysiological studies of {IT,} monkeys hold their direction of gaze fixed while isolated visual stimuli are presented (controlled viewing). However, during natural behavior, primates visually explore cluttered environments by changing gaze direction several times each second (free viewing). We examined the effect of free viewing on {IT} neuronal responses in monkeys engaged in a form-recognition task. By making small, real-time stimulus adjustments, we produced nearly identically retinal stimulation during controlled and free viewing. Nearly 90\% of neuronal responses were unaffected by free viewing, and average stimulus selectivity was unchanged. Thus, neuronal representations that likely underlie form recognition are virtually unaltered by free viewing.

}, keywords = {Animals, Conditioning, Fixation, Form Perception, Macaca mulatta, Male, Neurons, Ocular, Pattern Recognition, Photic Stimulation, Psychology, Saccades, Temporal Lobe, Visual, Visual Cortex}, issn = {1097-6256}, doi = {10.1038/77722}, url = {http://www.nature.com/articles/nn0800_814}, author = {DiCarlo, James J. and Maunsell, John H. R.} }