Fig. 5.

Specificity of FD1b and HS cells for object and background motion. Average response amplitudes during periods in which the ipsilateral background moved in the preferred direction of both cell types in the absence of an object (white columns) and during object motion in the preferred direction (shaded columns). a, Responses of FD1b cells ipsilateral to the object as obtained after subtraction of the spontaneous activity (average, 9 spikes/sec). b, Difference between the responses of the FD1b cells of both optic lobes. c,Responses of the HS cells ipsilateral to the object as obtained after subtraction of the resting potential (average, −44 mV).d, Difference between the responses of the HS cells of both optic lobes. n = 6 cells (a, b); n = 5 cells (c, d). Error bars indicate SEM.