Figure 3.

Same unit as in Fig. 2. A, responses to shining a rectangular light spot, 1 deg × 8 deg; centre of slit superimposed on centre of receptive field; successive stimuli rotated clockwise, as shown to left of figure. B, responses to a 1 deg × 5 deg slit oriented in various directions, with one end always covering the centre of the receptive field: note that this central region evoked responses when stimulated alone (Fig. 2a). Stimulus and background intensities as in Fig. 1; stimulus duration 1 s.