Fig. 1: Cells in face patches are modulated by familiarity.

a, Two alternative schemes for face representation: a low-dimensional (low-d) continuous feature space (left) and a set of discrete attractors (right). b, Left, view preference test. Pairs of faces (n = 72), one familiar and one unfamiliar, were presented for 10 s and the time spent fixating each was recorded. Right, ratio of time spent fixating personally familiar versus unfamiliar faces for two animals (each dot represents one face pair). Error bar, mean ± s.e.m. c, Responses of cells to stimuli from six stimulus categories (familiar human faces, unfamiliar human faces, familiar monkey faces, unfamiliar monkey faces, familiar objects and unfamiliar objects) across three face patches (AM, PR and TP). Responses were averaged between 50 and 300 ms following stimulus onset (‘full’-response window; AM, n = 152 cells; PR, n = 171 cells; TP, n = 266 cells; Supplementary Methods and Supplementary Table 1 provide additional statistical information). d, Same as c but for the ‘short’-response window (AM, 50–125 ms; PR, 50–150 ms; TP, 50–150 ms). e, Similarity (Pearson correlation coefficient) matrix of population responses for full-response window. f, Same as e but for short-response window. g, Left, average response time course across AM (top), PR (middle) and TP (bottom) populations to each of the screening stimuli. Right, AM, PR and TP response time courses averaged across both cells and category exemplars (normalized for each cell; Supplementary Methods). Left-hand arrow indicates mean time when visual responses to faces became significantly higher than baseline (AM, 85 ms; PR, 105 ms; TP, 75 ms; Supplementary Methods); right-hand arrow indicates mean time when responses to familiar versus unfamiliar faces became significantly different (AM, 105 and 145 ms for human and monkey faces, respectively; PR, 155 and 215 ms, respectively; TP, 145 and 205 ms, respectively). Shaded areas, s.e.m. across neurons.

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