Fig. 2: Expectation affects orientation-selective responses of individual V1 neurons.

a Time-courses of three example neurons in response to oriented grating stimuli in the expected, Unexpected and Random conditions. Each neuron is illustrated in a separate row, with the rightmost panel showing orientation tuning curves for that neuron. The tuning is measured as the averaged response from 250 to 1000 ms after stimulus onset (grey shading). The solid curve is a fitted Gaussian function with a constant offset. b Same as in A, but shows activity for all orientation-selective neurons (N = 462 neurons) aligned to their preferred orientation (0°) to allow averaging. Right panel: Same as in A but showing the Gaussian tuning function for the population response. c Response to the preferred orientation across the three conditions for all orientation-selective neurons. For presentation the time-courses are smoothed with a Gaussian with a 33.3 ms kernel. Every row represents the response of one neuron. In each panel, neurons are sorted based on their evoked response in the Unexpected condition (most excited on the top). d Comparison of the response in the Unexpected and Random conditions at the preferred orientation. Each dot represents one neuron. Purple dots show neurons significantly modulated by expectation (N = 133 neurons); grey dots are non-modulated neurons (N = 329 neurons). e Time-course of orientation-selectivity (circular mean) for the Random (blue) and Unexpected (green) conditions. Black horizontal lines indicate timepoints with statistically significant difference between conditions, determined using non-parametric cluster-corrected procedures (see Methods). f Summary statistics (n = 462) for fitted Gaussian parameters across the population for the different sequence types. All parameters are shown in Supplementary Fig. 1 for all three conditions. The Gain is the amplitude of the Gaussian. The insert shows the distribution of the difference between the two conditions (random minus unexpected). The purple line shows the zero point. Across all panels error bars and shading represent ± 1 standard error of mean. All statistical tests were two sided.