Cortical Evoked Response during Dynamic Visual Stimulation on Sitting and Orthostatic Positions

摘要

The Coherent Average of the multi-channel EEG signals of 14 healthy volunteers was used to estimate the motion-related visual evoked potential (M-VEP) in order to investigate the cortical processing elicited by dynamic visual stimulation (backward motion) applied during distinct postural positions: orthostatic (O) and sitting (S). For both positions, the grand averaged M-VEPs presented the P1, N2 (dominant peak) and P3 components with higher values for parietal leads, during O position. The results also revealed a right temporal shift on the M-VEP pattern during S position in central EEG leads, when compared with O (p<0.10). In addition, the running t-test results (α = 0.10) showed that the waveform for the O position statistically differs from that for S, 600 ms after the onset of backward motion, with a time delay in a spatial-temporal order from the parietal and frontal to central leads, which may be related with higher order of the cognitive, planning and motor brain processing linked to perception-action cycle. The running t-test also presented a short time lag for S position, suggesting that the early cortical response for O posture could probably be related with brain supplies to recovery balance after visual perturbation.