Pattern-evoked potential latencies from central and peripheral visual fields

Median P100 and N70 latencies for peripheral field (>8 degrees) TV-generate d pattern visual-evoked potentials were 6 and 8 milliseconds less than for central field patterns in subjects with normal pattern visual-evoked potent ials. These differences held for patient subgroups with P100 latency maxima from 140 to 100 milliseconds, and for left and right eye data separately c ompiled. Latencies for central field stimulation exceeded those for periphe ral field stimulation in 233 (85%) of 274 eyes for the N70 potential and in 210 (77%) of 274 eyes for the P100 potential. Such data suggest that the f aster conducting peripheral visual system, conveying location and motion in formation, prepares the occipital cortex for the later arriving central dat a conveying more intricate details.