@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 {89, title = {Using Neuronal Latency to Determine Sensory{\textendash}Motor Processing Pathways in Reaction Time Tasks}, journal = {Journal of Neurophysiology}, volume = {93}, year = {2004}, month = {11/2004}, pages = {2974 - 2986}, abstract = {

We describe a new technique that uses the timing of neuronal and behavioral responses to explore the contributions of individual neurons to specific behaviors. The approach uses both the mean neuronal latency and the trial-by-trial covariance between neuronal latency and behavioral response. Reliable measurements of these values were obtained from single-unit recordings made from anterior inferotemporal (AIT) cortex and the frontal eye fields (FEF) in monkeys while they performed a choice reaction time task. These neurophysiological data show that the responses of AIT neurons and some FEF neurons have little covariance with behavioral response, consistent with a largely \"sensory\" response. The responses of another group of FEF neurons with longer mean latency covary tightly with behavioral response, consistent with a largely \"motor\" response. A very small fraction of FEF neurons had responses consistent with an intermediate position in the sensory-motor pathway. These results suggest that this technique is a valuable tool for exploring the functional organization of neuronal circuits that underlie specific behaviors.

}, keywords = {Action Potentials, Afferent, Animal, Animals, Behavior, Macaca mulatta, Male, Models, Motor Neurons, Neural Pathways, Neurological, Neurons, Photic Stimulation, Psychomotor Performance, Reaction Time, Task Performance and Analysis, Temporal Lobe, Time Factors, Visual Fields}, issn = {0022-3077}, doi = {10.1152/jn.00508.2004}, url = {https://www.physiology.org/doi/10.1152/jn.00508.2004}, author = {DiCarlo, James J. and Maunsell, John H. R.} } @article {99, title = {Anterior Inferotemporal Neurons of Monkeys Engaged in Object Recognition Can be Highly Sensitive to Object Retinal Position}, journal = {Journal of Neurophysiology}, volume = {89}, year = {2003}, month = {01/2003}, pages = {3264 - 3278}, abstract = {

Visual object recognition is computationally difficult because changes in an object\&$\#$39;s position, distance, pose, or setting may cause it to produce a different retinal image on each encounter. To robustly recognize objects, the primate brain must have mechanisms to compensate for these variations. Although these mechanisms are poorly understood, it is thought that they elaborate neuronal representations in the inferotemporal cortex that are sensitive to object form but substantially invariant to other image variations. This study examines this hypothesis for image variation resulting from changes in object position. We studied the effect of small differences (+/-1.5 degrees ) in the retinal position of small (0.6 degrees wide) visual forms on both the behavior of monkeys trained to identify those forms and the responses of 146 anterior IT (AIT) neurons collected during that behavior. Behavioral accuracy and speed were largely unaffected by these small changes in position. Consistent with previous studies, many AIT responses were highly selective for the forms. However, AIT responses showed far greater sensitivity to retinal position than predicted from their reported receptive field (RF) sizes. The median AIT neuron showed a approximately 60\% response decrease between positions within +/-1.5 degrees of the center of gaze, and 52\% of neurons were unresponsive to one or more of these positions. Consistent with previous studies, each neuron\&$\#$39;s rank order of target preferences was largely unaffected across position changes. Although we have not yet determined the conditions necessary to observe this marked position sensitivity in AIT responses, we rule out effects of spatial-frequency content, eye movements, and failures to include the RF center. To reconcile this observation with previous studies, we hypothesize that either AIT position sensitivity strongly depends on object size or that position sensitivity is sharpened by extensive visual experience at fixed retinal positions or by the presence of flanking distractors.

}, keywords = {Action Potentials, Animals, Depth Perception, Electrophysiology, Eye Movements, Form Perception, Macaca mulatta, Male, Neurons, Pattern Recognition, Photic Stimulation, Psychomotor Performance, Retina, Temporal Lobe, Time Factors, Visual, Visual Fields, Visual Perception}, issn = {0022-3077}, doi = {10.1152/jn.00358.2002}, url = {https://www.physiology.org/doi/10.1152/jn.00358.2002}, author = {DiCarlo, James J. and Maunsell, John H. R.} } @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.} } @article {110, title = {Structure of Receptive Fields in Area 3b of Primary Somatosensory Cortex in the Alert Monkey}, journal = {The Journal of Neuroscience}, volume = {18}, year = {1998}, month = {04/1998}, pages = {2626 - 2645}, abstract = {

We investigated the two-dimensional structure of area 3b neuronal receptive fields (RFs) in three alert monkeys. Three hundred thirty neurons with RFs on the distal fingerpads were studied with scanned, random dot stimuli. Each neuron was stimulated continuously for 14 min, yielding 20,000 response data points. Excitatory and inhibitory components of each RF were determined with a modified linear regression algorithm. Analyses assessing goodness-of-fit, repeatability, and generality of the RFs were developed. Two hundred forty-seven neurons yielded highly repeatable RF estimates, and most RFs accounted for a large fraction of the explainable response of each neuron. Although the area 3b RF structures appeared to be continuously distributed, certain structural generalities were apparent. Most RFs (94\%) contained a single, central region of excitation and one or more regions of inhibition located on one, two, three, or all four sides of the excitatory center. The shape, area, and strength of excitatory and inhibitory RF regions ranged widely. Half the RFs contained almost evenly balanced excitation and inhibition. The findings indicate that area 3b neurons act as local spatiotemporal filters that are maximally excited by the presence of particular stimulus features. We believe that form and texture perception are based on high-level representations and that area 3b is an intermediate stage in the processes leading to these representations. Two possibilities are considered: (1) that these high-level representations are basically somatotopic and that area 3b neurons amplify some features and suppress others, or (2) that these representations are highly transformed and that area 3b effects a step in the transformation.

}, keywords = {Afferent, Animals, Data Interpretation, Electrophysiology, Female, Macaca mulatta, Male, Neural Inhibition, Neurons, Reproducibility of Results, Somatosensory Cortex, Statistical, Touch}, issn = {0270-6474}, doi = {10.1523/JNEUROSCI.18-07-02626.1998}, url = {http://www.jneurosci.org/lookup/doi/10.1523/JNEUROSCI.18-07-02626.1998}, author = {DiCarlo, James J. and Johnson, Kenneth O. and Hsiao, Steven S.} } @article {122, title = {A neural network approach to hippocampal function in classical conditioning.}, journal = {Behavioral Neuroscience}, volume = {105}, year = {1991}, month = {01/1991}, pages = {82 - 110}, abstract = {

Hippocampal participation in classical conditioning in terms of S. Grossberg\&$\#$39;s (1975) attentional theory is described. According to the theory, pairing of a conditioned stimulus/stimuli (CS) with an unconditioned stimulus/stimuli (UCS) causes both an association of the sensory representation of the CS with the UCS (conditioned reinforcement learning) and an association of the sensory representation of the CS with the drive representation of the UCS (incentive motivation learning). Sensory representations compete for a limited-capacity short-term memory (STM). The STM regulation hypothesis, which proposes that the hippocampus controls incentive motivation, self-excitation, and competition among sensory representations thereby regulating the contents of a limited capacity STM, is introduced. Under the STM regulation hypothesis, nodes and connections in Grossberg\&$\#$39;s neural network are mapped onto regional hippocampal-cerebellar circuits. The resulting neural model provides (a) a framework for understanding the dynamics of information processing and storage in the hippocampus and cerebellum during classical conditioning of the rabbit\&$\#$39;s nictitating membrane, (b) principles for understanding the effect of different hippocampal manipulations on classical conditioning, and (c) novel and testable predictions.\ 

}, keywords = {Animals, Cerebellum, Classical, Computer Simulation, Conditioning, Extinction, Eyelid, Hippocampus, Models, Nerve Net, Neurological, Neurons, Psychological, Rabbits, Reaction Time}, issn = {0735-7044}, doi = {10.1037/0735-7044.105.1.82}, url = {http://doi.apa.org/getdoi.cfm?doi=10.1037/0735-7044.105.1.82}, author = {Schmajuk, Nestor A. and DiCarlo, James J.} }