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Processing of novel sounds and frequency changes in the human auditory cortex: Magnetoencephalographic recordings |
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| Authors: | Kimmo Alho István Winkler Carles Escera Minna Huotilainen Juha Virtanen Iiro P Jääskeläinen Eero Pekkonen Risto J Ilmoniemi |
| Institution: | Cognitive Brain Research Unit, Department of Psychology, University of Helsinki, Finland;Neurodynamics Laboratory, Department of Psychiatry and Clinical Psychobiology, University of Barcelona, Spain;Institute for Psychology, Hungarian Academy of Sciences, Budapest, Hungary;BioMag Laboratory, Medical Engineering Centre, Helsinki University Central Hospital, Finland;Department of Radiology, Helsinki University Central Hospital, Finland;Department of Neurology, University of Helsinki, Finland |
| Abstract: | Whole-head magnetoencephalographic (MEG) responses to repeating standard tones and to infrequent slightly higher deviant tones and complex novel sounds were recorded together with event-related brain potentials (ERPs). Deviant tones and novel sounds elicited the mismatch negativity (MMN) component of the ERP and its MEG counterpart (MMNm) both when the auditory stimuli were attended to and when they were ignored. MMNm generators were located bilateral to the superior planes of the temporal lobes where preattentive auditory discrimination appears to occur. A subsequent positive P3a component was elicited by deviant tones and with a larger amplitude by novel sounds even when the sounds were to be ignored. Source localization for the MEG counterpart of P3a (P3am) suggested that the auditory cortex in the superior temporal plane is involved in the neural network of involuntary attention switching to changes in the acoustic environment. |
| Keywords: | Auditory cortex Attention MEG Novel sounds Mismatch negativity P3a |