REDUCTION OF VISUAL P300 DURING TRANSIENT GLOBAL AMNESIA

Transient global amnesia (TGA) is a syndrome of selective loss of rece nt memory without other neurological deficits. Auditory and visual P30 0s were recorded during and after TGA to investigate the contribution of the short-term memory system to P300 generation. The auditory P300 during TGA was comparable to that recorded 1 week and 9 months after T GA. In contrast to the auditory modality, the visual target P300 was r educed in amplitude during TGA and at 1 week after the attack. The P30 0 to novel visual stimuli was also reduced during TGA. Both target and novelty visual P300 recovered by 9 months after TGA. The results supp ort the notion that the neuronal networks responsible for P300 generat ion are modality dependent and that brain structures perfused by the p osterior circulation are involved in visual P300 generation.