Neural activity in speech-sensitive auditory cortex during silence

Hunter, M. D.; Woodruff, P. W. R.; Farrow, A. E.; Wilkinson, I. D.; Miller, T. W. R.; Eickhoff, S. B.

doi:10.1073/pnas.0506268103

Journal Article

Neural activity in speech-sensitive auditory cortex during silence

Hunter, M. D. ; Eickhoff, S. B.FZJ* ; Miller, T. W. R. ; Farrow, A. E. ; Wilkinson, I. D. ; Woodruff, P. W. R.

2006
Academy Washington, DC

Proceedings of the National Academy of Sciences of the United States of America 103, 189 - 194 (2006) [10.1073/pnas.0506268103]

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Please use a persistent id in citations: http://hdl.handle.net/2128/2690 doi:10.1073/pnas.0506268103

Abstract: That auditory hallucinations are voices heard in the absence of external stimuli implies the existence of endogenous neural activity within the auditory cortex responsible for their perception. Further, auditory hallucinations occur across a range of healthy and disease states that include reduced arousal, hypnosis, drug intoxication, delirium, and psychosis. This suggests that, even in health, the auditory cortex has a propensity to spontaneously "activate" during silence. Here we report the findings of a functional MRI study, designed to examine baseline activity in speech-sensitive auditory regions. During silence, we show that functionally defined speech-sensitive auditory cortex is characterized by intermittent episodes of significantly increased activity in a large proportion (in some cases >30%) of its volume. Bilateral increases in activity are associated with foci of spontaneous activation in the left primary and association auditory cortices and anterior cingulate cortex. We suggest that, within auditory regions, endogenous activity is modulated by anterior cingulate cortex, resulting in spontaneous activation during silence. Hence, an aspect of the brain's "default mode" resembles a (preprepared) substrate for the development of auditory hallucinations. These observations may help explain why such hallucinations are ubiquitous.

Keyword(s): Acoustic Stimulation (MeSH) ; Adult (MeSH) ; Auditory Cortex: physiology (MeSH) ; Auditory Pathways: physiology (MeSH) ; Auditory Perception: physiology (MeSH) ; Hallucinations: diagnosis (MeSH) ; Humans (MeSH) ; Magnetic Resonance Imaging (MeSH) ; Male (MeSH) ; Reference Values (MeSH) ; J ; auditory system (auto) ; baseline activity (auto) ; functional MRI (auto)