Abstract #0372

Fukunaga M, Duyn J, Fulton S, Balkin T, van Gelderen P, de Zwart J, Horovitz S

Recent BOLD fMRI studies have demonstrated the existence of ongoing activity in the absence of stimuli. However, the origin of this activity remains unknown, and might be purely vascular. In order to investigate this, we performed concurrent BOLD and perfusion-based fMRI and used the ratio of their fluctuation levels to establish metabolic involvement. We found that this ratio was similar between rest, sleep, and a visual task and significantly lower compared to a breatholding task. These results suggest that the phenomenon of resting state BOLD activity represents a metabolic process and continues during sleep