VEP-interhemispheric transfer time in 20-32 Hz band in man

This research aimed to investigate callosal transfer in the different frequency bands of VEP to lateralized reversal of checkerboard pattern as stimuli. The chosen band pass filters (4-8 Hz, 8-15 Hz, 15-20 Hz, 20-32 Hz) were applied to the VEPs of subjects, and four different components for each VEP were obtained. Latency differences between hemispheres for digitally unfiltered and filtered VEPs were computed to estimate IHTT. Different IHTTs in the theta (17 ms), alpha (9 ms) and beta1 (7 ms) bands from right to left and from left to right were estimated, supporting the previous report. Furthermore, a transfer within 4.5 ms from right to left in the 20-32 Hz band for the occipital lobe was found. In conclusion, our findings suggest that the frequency analysis of VEP to lateralized stimuli give us additional information, relating to the types of callosal fibers.