Abstract
The timing of VEP responses is a sensitive indicator of visual development. Past work has concentrated on responses to pattern reversal and to the latency of the initial positive peak. Here we compare the timing of VEP responses to pattern-, orientation-, and direction-reversal, and transient peak latencies to those calculated from the gradient of steady-state phase against reversal rate. The three stimuli were tested in 61 adults at 1- 16 r/s and 136 infants (age 3.6- 79.0 weeks) at 2- 8 r/s. Infants showed similar transient peak latencies for orientation and direction reversal, while adults showed similar pattern-reversal and orientation latencies. In both adults and infants calculated latencies for orientation and direction were significantly longer than the respective peak latencies. While transient latencies for the three stimuli converged around 20 weeks of age, calculated latencies of orientation and direction converged at 30 weeks. In summary, transient peak latencies of phase, orientation, and direction VEPs showed similar developmental trends suggesting possible parallel processing routes. Latencies calculated from steady-state phase, however, may reflect the timing of cortical feedback effects. While peak latency indicated that initial detection of motion matured before orientation, calculated latency revealed that the fine-tuning of orientation matured before motion processes.
Meeting abstract presented at VSS 2012