NEGATIVE CORRELATION OF P50 PEAK LATENCIES AND REACTION-TIMES IN A SIMPLE REACTION TASK

We investigated the influence of stimulus characteristics and tasks (c ount and simple reaction tasks) on auditory P50. Ten normal volunteers served as subjects. EEGs and auditory evoked potentials were obtained from Fz, Ct, Pt, C3, C4, T3 and T4 referred to linked earlobes (LE) a nd balanced non-cephalic (BN) electrodes. In the recordings using a BN reference there were significant negative correlations between the re action times and P50 peak latencies at Fz, Ct, Pt, C3 and C4. In the L E reference recordings there were negative correlations but these did not reach statistical significance. The results are discussed with ref erence to the activation of the LE reference and the neural sources of P50. The findings suggest the possibility that reaction times are det ermined at the very early stage of auditory information processing.