scholarly journals Relationship Between the Activities of Gloss-Selective Neurons in the Macaque Inferior Temporal Cortex and the Gloss Discrimination Behavior of the Monkey

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Mika Baba ◽  
Akiko Nishio ◽  
Hidehiko Komatsu
Keyword(s):  
Causal Relationship ◽  
Discrimination Task ◽  
Temporal Cortex ◽  
Discrimination Performance ◽  
Macaque Monkey ◽  
Inferior Temporal Cortex ◽  
Population Activity ◽  
Electrical Microstimulation ◽  
Neural Activities ◽  
Restricted Region

Abstract In the macaque monkey, neurons that selectively respond to specific gloss are present in a restricted region of the central part of the inferior temporal (IT) cortex. Although the population activity of these neurons is known to represent the perceptual gloss space, the involvement of their activity in gloss perception has not been directly tested. In the present study, we examined the causal relationship between the activities of gloss-selective neurons and gloss perception by applying electrical microstimulation or injection of small amounts of muscimol (GABAA agonist) to manipulate neural activities while monkeys performed a gloss discrimination task. We found that microstimulation within or in the vicinity of the region where gloss-selective neurons were recorded induced bias toward higher gloss judgment. With muscimol injection, gloss discrimination performance was degraded in one monkey after the first injection into the region where gloss-selective neurons were recorded. These results suggest that gloss discrimination behavior is mediated by the activities of a gloss-selective network that includes the gloss-selective region in the central IT cortex examined here.

Enhancement of inferior temporal neurons during visual discrimination

1987 ◽  
Vol 58 (6) ◽  
pp. 1292-1306 ◽  
Author(s):  
B. J. Richmond ◽  
T. Sato
Keyword(s):  
Spatial Attention ◽  
Trial Type ◽  
Discrimination Task ◽  
Temporal Cortex ◽  
Pattern Discrimination ◽  
Response Strength ◽  
The Other ◽  
Inferior Temporal Cortex ◽  
Attention Task ◽  
Type Pattern

1. Previous results have shown that spatially directed attention enhances the stimulus-elicited responses of neurons in some areas of the brain. In the inferior temporal (IT) cortex, however, directing attention toward a stimulus mildly inhibits the responses of the neurons. Inferior temporal cortex is involved in pattern discrimination, but not spatial localization. If enhancement signifies that a neuron is participating in the function for which that part of cortex is responsible, then pattern discrimination, not spatial attention, should enhance responses of IT neurons. The influence of pattern discrimination behavior on the responses of IT neurons was therefore compared with previously reported suppressive influences of both spatial attention and the fixation point. 2. Single IT neurons were recorded from two monkeys while they performed each of five tasks. One task required the monkey to make a pattern discrimination between a bar and a square of light. In the other four tasks the same bar of light appeared, but the focus of spatial attention could differ, and the fixation point could be present or absent. Either attention to (without discrimination of) the bar stimulus or the presence of the fixation point attenuated responses slightly. These two suppressive influences produced a greater attenuation when both were present. 3. The visual conditions and motor requirements when the bar stimulus appeared in the discrimination task were identical to those of the trials in the stimulus attention task. However, one-half of the responsive neurons showed significantly stronger responses to the bar stimulus when it appeared in the discrimination task than when it appeared in the stimulus attention task. For most of these neurons, discrimination just overcame the combined effect of the two suppressive influences. For six other neurons, the response strength was significantly greater during the discrimination task than during any other task. 4. The monkeys achieved an overall correct performance rate of 90% in both the discrimination and stimulus attention tasks. To achieve this performance in the discrimination task they adopted a strategy in which they performed one trial type, bar stimulus attention trials, perfectly (100%) and the other trial type, pattern trials, relatively poorly (84% correct).(ABSTRACT TRUNCATED AT 400 WORDS)

Functional mapping of the inferior temporal cortex (IT) of the macaque monkey

1988 ◽  
Vol 7 ◽  
pp. S212
Author(s):  
Keiji Tanaka ◽  
Hide-Aki Saito ◽  
Yoshiro Fukada ◽  
Madoka Fukumoto
Keyword(s):  
Temporal Cortex ◽  
Macaque Monkey ◽  
Functional Mapping ◽  
Inferior Temporal Cortex

scholarly journals Color tuning of neurons in face patches of macaque inferior temporal cortex

2019 ◽  
Author(s):  
Marianne Duyck ◽  
Tessa J. Gruen ◽  
Lawrence Y. Tello ◽  
Serena Eastman ◽  
Joshua Fuller-Deets ◽  
...  
Keyword(s):  
Second Harmonic ◽  
Temporal Cortex ◽  
Luminance Contrast ◽  
Macaque Monkey ◽  
Inferior Temporal Cortex ◽  
Color Tuning ◽  
Quantitative Measurements ◽  
Cone Activity ◽  
Insight Into

Previous work has shown that under viewing conditions that break retinal mechanisms for color, one class of objects appears paradoxically colored: faces, and they look green. Interpreted within a Bayesian-observer framework, this observation makes the surprising prediction that face-selective neurons are sensitive to color and weakly biased for colors that elicit L>M cone activity (warm colors). We tested this hypothesis by measuring color-tuning responses of face-selective cells in alert macaque monkey, using fMRI-guided microelectrode recording of the middle and anterior face patches and carefully color-calibrated stimuli. The population of face-selective neurons showed significant color tuning when assessed using images that preserved the luminance contrast relationships of the original face photographs. A Fourier analysis of the color-tuning responses uncovered two components. The first harmonic was biased towards the L>M colors, consistent with the prediction. Interestingly, the second harmonic aligned with the S-cone cardinal axis, which may relate to the computation of animacy by IT cells.SignificanceThe results provide the first quantitative measurements of the color tuning properties of face-selective neurons. The results provide insight into the neural mechanisms that could support the role of color in face perception.

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