Electrophysiological studies have revealed a pre-attentive change-detection system in the auditory modality. This system emits a signal termed the mismatch negativity (MMN) when any detectable change in a regular pattern of auditory stimulation occurs. The precise intracranial sources underlying MMN generation, and in particular whether these vary as a function of the acoustic feature that changes, is a matter of some debate. Using functional magnetic resonance imaging, we show that anatomically distinct networks of auditory cortices are activated as a function of the deviating acoustic feature--in this case, tone frequency and tone duration--strongly supporting the hypothesis that MMN generators in auditory cortex are feature dependent. We also detail regions of the frontal and parietal cortices activated by change-detection processes. These regions also show feature dependence and we hypothesize that they reflect recruitment of attention-switching mechanisms.
Pubmed ID: 15342438 RIS Download
Mesh terms: Adult | Auditory Cortex | Biological Clocks | Brain Mapping | Evoked Potentials, Auditory | Female | Humans | Image Interpretation, Computer-Assisted | Magnetic Resonance Imaging | Male | Nerve Net | Pitch Discrimination
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