Abstract #0405

Henry P, van de Moortele P, Gruetter R, Seaquist E, Oz G

Utilization of brain glycogen during brain activation was investigated after pre-labeling glycogen with i.v. infusions of [1-13C]glucose over extended periods (13-50 h) in five healthy volunteers. No difference in [1-13C]glycogen signal localized to the visual cortex was observed after 20 minutes of visual stimulation with a checkerboard pattern. This observation supports the hypothesis that bulk brain glycogen is mobilized when glucose supply becomes rate-limiting for metabolism. A small fraction of glycogen may still be highly active under normal physiology.