@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 {107, title = {Velocity Invariance of Receptive Field Structure in Somatosensory Cortical Area 3b of the Alert Monkey}, journal = {The Journal of Neuroscience}, volume = {19}, year = {1999}, month = {01/1999}, pages = {401 - 419}, abstract = {

This is the second in a series of studies of the neural representation of tactile spatial form in cortical area 3b of the alert monkey. We previously studied the spatial structure of 330 area 3b neuronal receptive fields (RFs) on the fingerpad with random dot patterns scanned at one velocity (40 mm/sec;\ DiCarlo et al., 1998). Here, we analyze the temporal structure of 84 neuronal RFs by studying their spatial structure at three scanning velocities (20, 40, and 80 mm/sec). As in the previous study, most RFs contained a single, central, excitatory region and one or more surrounding or flanking inhibitory regions. The mean time delay between skin stimulation and its excitatory effect was 15.5 msec. Except for differences in mean rate, each neuron\’s response and the spatial structure of its RF were essentially unaffected by scanning velocity. This is the expected outcome when excitatory and inhibitory effects are brief and synchronous. However, that interpretation is consistent neither with the reported timing of excitation and inhibition in somatosensory cortex nor with the third study in this series, which investigates the effect of scanning direction and shows that one component of inhibition lags behind excitation. We reconcile these observations by showing that overlapping (in-field) inhibition delayed relative to excitation can produce RF spatial structure that is unaffected by changes in scanning velocity. Regardless of the mechanisms, the velocity invariance of area 3b RF structure is consistent with the velocity invariance of tactile spatial perception (e.g., roughness estimation and form recognition).

}, keywords = {Adaptation, Animals, Brain Mapping, Cortical Synchronization, Evoked Potentials, Female, Macaca mulatta, Male, Neural Inhibition, Physiological, Somatosensory Cortex, Visual Fields}, issn = {0270-6474}, doi = {10.1523/JNEUROSCI.19-01-00401.1999}, url = {http://www.jneurosci.org/lookup/doi/10.1523/JNEUROSCI.19-01-00401.1999}, author = {DiCarlo, James J. and Johnson, Kenneth O.} }