Fig. 1.

Characteristics of spontaneous eye movement in the dark. A: mean eye position during silent (red) and stimulus (blue) epochs recorded over the course of a sample session from a single site. Only data from those trials in which movement did not exceed a 2-deg threshold are displayed (see methods). B: average eye positions analyzed during the silent period across all recordings for each monkey. Horizontal eye position (top) was distributed fairly normally, although there was some variation across subjects. Monkeys more often directed gaze at points above the vertical meridian (bottom). C: distributions of the total movement magnitude over all trials during the silent period. The threshold for including trials is indicated. Results for spontaneous eye positions measured during auditory stimuli were the same (data not shown). Horiz., horizontal; vert., vertical; eye pos., eye position.