Influence of regional cerebral blood flow on event-related potential (P300)

The relationships between event-related potential (P300), higher brain functions, and regional cerebral blood flow (rCBF) were examined in 31 neurosurgical patients. The P300 latency, evaluated by an acoustic "odd-ball" paradigm, was normal in 14 and prolonged in 17 patients. Fourteen of 17 prolonged P300 patients had reduced rCBF in the right cerebral hemisphere, especially the frontal lobe and/or thalamus. There was a significant inverse relationship between P300 latency and laterality index (rt rCBF/lt rCBF) in the frontal lobe. Prolonged P300 patients revealed significant abnormalities in psychological tests compared to normal P300 patients. There were significant inverse relationships between the P300 latency and "orientation" and "memory" test scores. Decreased rCBF in the right cerebral hemisphere, especially the frontal lobe and/or thalamus, is associated with prolonged P300 latency, suggesting that the right cerebral hemisphere is important in human cognitive processes.