A neural substrate for musical hallucinosis

This study used Positron Emission Tomography (PET) to define areas of brain activation during musical hallucinosis in a single subject with deafness but no psychiatric or central neurologic condition. The subject had a history of less than 6 months of continual hallucinosis in the form of hearing one or more singers singing familiar songs with indistinguishable lyrics. A parametric design was used to identify areas where blood flow increased as a function of the intensity of the hallucination, and revealed significant activation in the posterior middle right temporal lobe. A region in the anterior superior right temporal lobe just failed to reach significance. Significant decreases in blood flow with increasing intensity of the hallucination were demonstrated in the occipital cortex, These data implicate right temporal lobe mechanisms beyond the primary auditory cortex in musical imagery.