Do changes in cerebral blood flow modulate the amplitudes of P300 during cognitive task?

A single session of aerobic or resistance training transiently enhances cognitive function, making it a valuable strategy for dementia prevention in the older people. Despite its acknowledged benefits, the precise mechanism behind exercise-induced cognitive improvement remains controversial. In the present study, we investigated the impact of altered cerebral blood flow (CBF) on brain neural activity originating from motor executive and inhibitory processing using electroencephalographic event-related potentials (EEG-ERPs). Sixteen healthy subjects participated in four sessions, with EEG-ERPs measured during somatosensory Go/No-go tasks. The sessions were conducted under four distinct respiratory conditions presented in random order: normal breathing (NB) and rapid breathing (RB) with room air, normal breathing with hypercapnic gas (5% CO₂, 21% O₂, and balanced N₂) (NB + Gas), and rapid breathing with the same gas (RB + Gas). Changes in CBF were evaluated based on the middle cerebral artery mean blood velocity (MCA V_mean) using transcranial Doppler. [Formula: see text] was decreased under the RB condition but increased under the NB + Gas condition, thereby decreasing and increasing MCA V_mean, respectively. Under the NB + Gas condition, MCA V_mean significantly increased, but it had no effect on either the executive or inhibitory function. In contrast, the reduction in MCA V_mean induced by RB decreased the peak amplitudes of Go-P300 and No-go-P300. However, even under the RB + Gas condition while MCA V_mean increased, the peak amplitudes of both also decreased. These findings suggest that neither increases nor decreases in CBF affected cognitive function.<b>NEW & NOTEWORTHY</b> A single session of aerobic or resistance training transiently enhances cognitive function, but the precise mechanism behind this exercise-induced cognitive improvement remains unknown. We investigated the effect of altered cerebral blood flow (CBF) on brain neural activity originating from motor executive and inhibitory processing using electroencephalographic event-related potentials. Exercise-induced improvement in cognitive function could not be explained by an increase in CBF, whereas a decrease in CBF did not affect cognitive function.