EVOKED-POTENTIALS AND SIMPLE MOTOR REACTION-TIMES TO LOCALIZED VISUAL-PATTERNS

Spatially localized, contrast modulated visual stimuli evoke a monopha sic, inion negative scalp potential (VEP) which can be recorded simult aneously with motor responses in simple reaction time experiments. VEP response time and median motor response latency are linearly related over a wide range of stimuli. We interpret our results to suggest that VEPs and motor response latencies arise from a common sensory system with different thresholds for detection and reaction. A model is intro duced to predict detection thresholds from VEP response times which ar e usually more robust measures than VEP amplitudes.