Fig. 4.

Responses of two representative MT cells, shown as PSTHs. Each small axis shows the response to the stimuli presented in the corresponding spatial location. Each is only 150 msec in duration; the responses of each cell were individually normalized, and the vertical calibration is indicated in the bottom left PSTH. The locations of each stimulus grid are indicated in degrees relative to the center of gaze. The vertical calibration bars express firing rate in impulses/sec. The ratios of the size of the sampling grid to the derived RF size (see Fig. 5) were 1.84 for the cell in A and 0.84 for the cell in B. The geometric mean of this ratio was 1.33 for our sample of cells.