EFFECT OF TARGET DURATION ON SACCADES TO DOUBLE TARGETS

Title EFFECT OF TARGET DURATION ON SACCADES TO DOUBLE TARGETS
Author, Co-Author A. Aitsebaomo, Harold Bedell
Topic
Year
1994
Day
Tuesday
Program Number
3:00 pm
Room
San Diego Ballroom A
Affiliation
Abstract Saccades to similar targets that are presented simultaneously have been reported to land somewhere between the targets -- saccadic averaging. We evaluated the amplitudes of saccades to single and double targets (separated by 2 or 4 deg) when the processing of target position information was interrupted by a masking stimulus presented immediately after the target(s). The targets were bright vertical lines presented on a Commodore VIC computer for durations ranging from 33 to 100 ms; single and double targets were interleaved in each run. Each presentation was preceded by an auditory cue that signalled the subject (N=2) to saccade to the nearer or the farther target, if two targets were shown. As we reported previously, the saccades to double targets showed little or no averaging when the targets were presented for 100 ms. Averaging increased as the duration of the targets decreased, primarily because of a reduction in the amplitude of saccades to the farther target. Psychophysical results from the same subjects indicated that the spatial separation required to discriminate between single and double lines also increased as the duration of the targets decreased. Unlike the previously reported saccadic averaging for long-duration targets, the averaging we observed for targets of short duration is likely to result from poor spatial resolution when the saccadic system is not afforded sufficient processing time.
Affiliation of Co-Authors
Outline