Figure 6. Attention gates orientation encoding in the pulvinar.

a) Stimuli for the orientation decoding control experiment. Gabor patches were presented in the four visual quadrants; the Gabors could be oriented at −45 or +45 deg. with respect to vertical, and the orientations in the upper and lower visual fields varied independently (left and right Gabors within the upper or lower visual field were always oriented orthogonally). Subjects attended for brief orientation changes in the cued Gabors, ignoring the others. b) Classification of attended and ignored orientations within the pulvinar. ±1sd of chance classification, estimated by classifying with shuffled labels, is shown by the shaded region (Supplementary Methods). There was reliable classification of attended orientations (red bar; 54.7% correct; 7.8 standard deviations above the mean of the bootstrapped chance distribution; p < 0.001), but chance classification of ignored orientations (blue bar; 49.9% correct; 0.34 standard deviations below bootstrapped chance; p = 0.62) in the pulvinar (n = 192 training blocks and 48 test blocks per subject for both tests; data shown are collapsed across three subjects). Classification of attended orientations was significantly better than classification of ignored orientation (p < 0.001; nonparametric bootstrap test for whether the attended-chance difference was larger than the ignored-chance difference; n = 192 training blocks and 48 test blocks per subject in each condition). c) In early visual areas (V1 through MT+), orientation classification was significantly above chance for both attended and ignored Gabors (56.3% correct for attended and 54.3% correct for ignored, 10.1 and 6.8 standard deviations above bootstrapped chance, respectively; both p < 0.001; n = 192 training blocks and 48 test blocks per subject for both tests). Attended orientations were classified significantly better than ignored orientations in early visual areas (p = 0.016; bootstrap test for [attended-chance] > [ignored-chance]), but the modulation of orientation coding by attention was significantly stronger in the pulvinar than in early visual areas (p = 0.012; bootstrap test for [pulvinar_attended-pulvinar_ignored] > [early vis_attended-early vis_ignored]; n = 192 training blocks and 48 test blocks per subject per condition for both tests).