Abstract #2844

Wilkinson I, Hunter M, Eickhoff S, Miller T, Farrow T, Woodruff P

Auditory hallucinations occur in health and disease implying the existence of neuronal activity in the absence of external stimuli. This work sought to characterise human auditory BOLD signal during silence. Baseline activity was examined in 12 normal subjects using a SPARSE-EPI protocol. Data show that functionally defined auditory cortex is characterised, during silence, by intermittent episodes of significantly increased signal in up to 30% of its volume. Significant contrast was detected in left primary/association auditory cortices and anterior cingulate. The findings support the presence of a vascular response-mechanism that may underpin spontaneous auditory hallucinations.