Figure 4.

Visually driven response time courses in cat area 17. A, Fluorescence intensity changes during and after a 6 s visual stimulus (black bar shows the duration of the stimulus). Responses are plotted for a pixel in a horizontal-preferring orientation domain. The visual stimulus consisted of either a horizontal (thick line) or vertical (thin line) square-wave grating drifting through the visual field. The baseline intensity in the first frame of each stimulus presentation was subtracted. B, Reflectance changes at 610 nm (ISI) at a different location than the traces in A, but that had the same orientation preference. Response amplitudes have been inverted such that increases in absorbance are upward deflections. C, Plots of autofluorescence changes from the same point as in A, but after spatial high-pass filtering the images. D, Plots of reflectance changes from the same point as in B after spatial high-pass filtering the images. The traces show the mean response over 15 trials, and error bars are SEM.