Fig. 7.

Target motions used to demonstrate a difference in the nasal bias for responses to brief perturbations of target motion, depending on whether the perturbations were presented during fixation (A) or ongoing pursuit (B). Data are for viewing with the right eye by strabismic monkey SY. Dashed traces show target speed and position, and solid traces show eye position and speed. Perturbations were provided by brief pulses of target speed with amplitudes of 5 deg/sec and durations of 150 msec. A, Example of the response to a nasalward perturbation of target motion presented during fixation. B, Example of a response to the same nasalward perturbation presented during pursuit of target motion at 15 deg/sec. Interruptions of the eye speed trace occur where saccades were excised from the record. The arrows inA and B indicate the responses to the pulses. C, The upper traces show averaged eye and target speed records from interleaved sets of trials in which the speed pulses were nasalward (5N), temporalward (5T), or absent. The lower traces show eye speed difference records, obtained by subtracting averaged eye speed during the two types of “pulse” trials from averaged eye speed on “no-pulse” trials. Upward deflections of the traces show rightward or, in this case, temporalward eye and target motion.