Task and recording sites.

(A) Illustration of the behavioral tasks. A central cue was presented first to indicate the category of the searched-for target, then a search array with eleven stimuli including two target stimuli and nine distractors appeared on the screen. The cue and the two targets belonged to the same category, but the targets were always different from the cue. Monkeys were rewarded for fixating on either one of the targets for ⩾800 ms. (B) Stimuli of Face category and House category. (C) MRI images showing the typical recording regions of V4, IT and LPFC. Red arrows indicated the electrode trace directions.

Foveal feature attentional modulation in V4 and IT.

(A) Normalized firing rates averaged across the IT foveal Face-selective cells during Face Target, Face Distractor, House Target, and House Distractor fixations (see methods). All firing rates were normalized to the maximum rates of the attended responses of preferred category. Shading around average firing rates indicates the SEM (±). (B)-(F) show the normalized population responses in V4 Face-selective cells, IT House-selective cells, V4 House-selective cells, IT Non-selective cells and V4 Non-selective cells, respectively. For non-selective cells, Face Target and House Target fixations were combined into “Target” fixations, and Face Distractor and House Distractor fixations were combined into “Distractor” fixations. Firing rates were normalized to the maximum rates of the “Target” responses.

Peripheral feature and spatial attentional modulation in V4, IT and LPFC.

(A)-(C) show population responses of peripheral Non-selective cells to target stimuli (“Target”) and to matched distractor stimuli (“Distractor”) in V4, IT and LPFC, respectively. (D)-(F) show population responses of these cells to stimuli followed by saccades into their RF (Attention In) and out of their RF (Attention Out) in V4, IT and LPFC, respectively.

Temporal relationship of attentional modulation in the foveal and the peripheral.

(A) Cumulative distribution of feature attention effect latencies in V4 and IT, computed from individual foveal Face-, House- and Non-selective units and represented as proportions of the total units. (B)-(C) show cumulative distributions of feature attention effect latencies of the foveal and peripheral units in IT and V4, respectively.

Influence of foveal feature attention state on the peripheral feature attentional modulation.

(A), (D), (G) show population responses of peripheral Non-selective cells to target stimuli (“Target”) and to matched distractor stimuli (“Distractor”) without considering central fixations in V4 (N = 396), IT (N = 123), and LPFC (N = 350), respectively. (B), (E), (H) show responses of these cells to target stimuli and to matched distractor stimuli during distractor fixations. The Target and Distractor conditions during distractor fixations are illustrated above (B). (C), (F), (I) show responses of these cells to target stimuli and to matched distractor stimuli during target fixations. The Target and Distractor conditions during target fixations are illustrated above (C).

Influence of foveal feature attention state on the peripheral spatial attentional modulation.

(A), (D), (G) show spatial attention effects of V4 peripheral Non-selective cells (N = 651), IT peripheral Non-selective cells (N = 191), and LPFC peripheral Non-selective cells (N = 425), respectively. (B), (E), (H) show spatial attention effects of these cells when the features of foveal stimulus were not attended. The Attention In and Attention Out conditions during distractor fixations are illustrated above (B). (C), (F), (I) show spatial attention effects of these cells when the features of foveal stimulus were attended. The Attention In and Attention Out conditions during target fixations are illustrated above (C).

Feature and spatial attention distribution during search.

(A)-(C) show feature and spatial attention effects of Non-selective units during D-D fixations in V4 (N = 727), IT (N = 216), and LPFC (N = 464), respectively. Illustration of feature and spatial attention distribution during D-D fixations is on the right of (C). (D)-(F) show feature and spatial attention effects of these units during D-T fixations in V4 (N = 730), IT (N = 216), and LPFC (N = 465), respectively. Illustration of feature and spatial attention distributions during D-T fixations is on the right of (F). (G)-(I) show feature and spatial attention effects of these units during T-D fixations in V4 (N = 600), IT (N = 212), and LPFC (N = 423), respectively. Illustration of feature and spatial attention distributions during T-D fixations is on the right of (I). (J)-(L) show feature and spatial attention effects of these units during T-T fixations in V4 (N = 676), IT (N = 200), and LPFC (N = 436), respectively. Illustration of feature and spatial attention distributions during T-T fixations is on the right of (L).

Influence of stimulus category on the attentional modulation.

(A)-(D) show the feature attentional effects on responses from low to high to 4 subsets of House stimuli in IT House-selective cells (N = 339), respectively. The rectangle shading indicates the time window (150 - 225 ms after fixation onset) used for analyzing the attentional effects. (E)-(H) show the feature attentional effects on responses from low to high to 4 subsets of Face stimuli in IT House-selective cells (N = 339), respectively. (I) The attention effects on responses to subsets of Face stimuli and House stimuli in IT House-selective cells. X axis: the amplitude of normalized visual response to subsets of House and Face stimuli; Y axis: the amplitude of attentional effects (Attended – Unattended) on response to these stimulus subsets. Visual response was calculated in a window of 50 - 225 ms after fixation onset, while the subsets of stimuli were not attended. (J)-(L) show the attention effects on responses to stimulus subsets in IT foveal Face-selective cells (N = 480), V4 foveal House-selective cells (N = 301), and V4 foveal Face-selective cells (N = 266), respectively.