Area PEc Neurons Use a Multiphasic Pattern of Activity to Signal the Spatial Properties of Optic Flow

Figure 1

Stimuli. (a) Temporal sequence of the behavioral task. Monkeys were trained to push a lever when the FP appeared on the screen (A). After one second, 1000 random dots appeared (B). After one second the expansion stimulus started at a speed of about 10°/s (C), followed after one second by the contraction stimulus (D). The monkey had to detect a change in FP orientation (E) and release the lever within a maximum reaction time of 500 ms. (b) Retinotopic condition. The FP was presented in the center of the screen, and FOE in one of nine locations in a grid at 15° distance each. Black circles indicate other FOE peripheral positions. (c) Eye position test. The FOE was presented in the center of the screen, while FP was in one of the nine peripheral locations. Black circles indicate other FP peripheral positions. (d) Angle of gaze condition. FP and FOE were displayed concentrically in one of the nine locations. Black circles indicate other FP/FOE positions. FP: fixation point; FOE: focus of expansion.

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