Effect of photic stimulation (PS) on energy metabolism in the human
occipital cortex was examined by using phosphorus-31 magnetic resonance
spectroscopy in 9 normal subjects. Phosphocreatine (PCr)/total phosphorus
signal peak area ratio significantly decreased from 12.3% to 10.9% during
the 12 minutes of PS (P < 0.05). PCr once returned to a normal level
after PS (11.9%) but significantly decreased again 12-18 minutes after PS
(10.8%; P < 0.05). Intracellular pH increased from 7.08 to 7.16 during
PS, although this increase was not significant. These results suggest that
functional alteration of energy metabolism in the brain is different from
that in muscles.Abstract Teaser