Activity of neurons in monkey posterior temporal cortex during multidimensional visual discrimination tasks.

Unit activity was recorded from the posterior temporal cortex (PTE) of awake, behaving rhesus monkeys while they performed a series of visual discrimination tasks involving colored checkerboard patterns. The activity of 130 (91%) of 143 PTE units was altered by the presentation of a visual discriminandum; 112 of these cells (86%) exhibited a significant increase in firing after presentation of the stimulus while the remainder gave an inhibitory response. Over half (64%) the PTE units exhibited differential activity between discriminanda, i.e. they were selective for color and/or form. Six of 10 neurons, recorded when the monkey was required to shift attention from one stimulus feature to another, exhibited a difference in poststimulus neural activity even though the discriminandum remained the same. Three neurons were recorded from when the stimuli were altered by changing the check size although the relevant (i.e. rewarded) dimension (color) was left the same; two showed an invariant response to the altered stimuli and one gave the same response to one of the altered stimuli but a different response to the other. These data support the role of posterior temporal cortex in visual discrimination learning and visual attention.