Energetics of 3.5 s Neural activation in humans: A 31P MR spectroscopy study

No direct information on brain energetics and energy-related compounds in the first seconds of physiological activation has been reported to date. In this study visual cortex high energy phosphate changes were monitored in 11 normal subjects during 3.5 s activation and the following 23.5 s by a simple ³¹P magnetic resonance spectroscopic method. An intraactivation decrease of phosphocreatine (PCr) was observed in all subjects, with changes in pH in three, one of them also presenting a change in adenosine triphosphate (ATP). In the subgroup of eight subjects without changes in pH, the mean rate of mean PCr decrease (D(pcr)) was 7.24 ± 0.78 %/s, and the postactivation mean rate of mean PCr recovery was