a: Stimuli were sequences of gratings with random orientation.
b: Layout of a 10×10 electrode array aligned with a map of preferred orientation (replotted from Ref. ).
c: Tuning curves of neurons grouped by preferred orientation, measured with a uniform stimulus. Responses are scaled to the values of 1 at the preferred orientation and 0 at the orthogonal orientation.
d: Tuning curves measured with a biased stimulus, where the orientation of 0 deg was presented more often than the others. Thicker curves in c and d are tuning curves of neurons selective for -15 deg and +15 deg.
e: A segment of the stimulus sequence in the uniform ensemble. Each dot symbolizes a grating. In the whole sequence, the probability of presentation across orientations is flat (bottom panel).
f: Responses to the sequence in e. Each orientation bin is normalized to its own time average (bottom panel).
g: Fitted responses using the homogeneous tuning curves. Time averages are in bottom panel, blue line.
h: Simulation made using the adapted tuning curves. Time averages are in bottom panel, red line.
i-j: Same as e-f, but for a biased stimulus ensemble. Responses have the same scaling factor as those in f.
k: Simulation made using the homogeneous tuning curves.
l: Fitted responses using the adapted tuning curves.
Data in this figure are from experiments 75-6-2+3, with adaptor probability of 35%. Error bars in J-l bottom panels, ± 1 s.d.