Spectral Analysis of Cortical EEG Activity During Simultaneous Auditory and Visual Stimulation

摘要

Cortical EEG activity was recorded from six chronically implanted cats when auditory click stimuli were presented before, during, and after simultaneous accessory photic stimulation at seven different intensities. Sample epochs of auditory-cortex EEG activity from the three recording sessions, in the absence of bodily movement, were subjected to the fast-Fourier transform, and the average power spectra were determined for several frequency bands. The amount of power within the theta frequency range was not significantly different during simultaneous visual and auditory stimulation when compared with the pretest and posttest control periods of auditory stimulation, except at the most intense level of light stimulation (323 1x). Simultaneous auditory and visual stimulation had no systematic effect on the amount of power occurring in the alpha, beta 1, and beta 2 frequency bands. The results indicate that sensory stimulation does not produce hippocampal RSA (rhythmic slow activity) during behavioral immobility when both the auditory and visual are irrelevant, except at very intense levels of stimulation.