IngentaConnect Localization of Primary Auditory Cortex in Humans by Magnetoencep...

Authors: Lütkenhöner B.¹; Krumbholz K.¹; Lammertmann C.¹; Seither-Preisler A.¹; Steinsträter O.¹; Patterson R.D.²

Source: NeuroImage, Volume 18, Number 1, January 2003 , pp. 58-66(9)

Abstract:

Brief auditory stimuli activate the primary auditory cortex (PAC) earlier than any other cortical area so, within a certain latency range, the PAC is the only cortical source contributing to the auditory evoked field (AEF). Nevertheless, there is no AEF component specific to PAC that can be reliably detected in all individuals. The present study suggests that a peak in the first temporal derivative of the magnetic field at about 20 ms (dP20m) is a genuine correlate of PAC activity. AEFs in response to clicks presented to the right ear were recorded with a 37-channel axial gradiometer system positioned over the left hemisphere in nine normal-hearing subjects. More than 8500 stimuli were presented in each of two independent sessions at a rate of approximately 3/s. The dipole coordinates for the dP20m derived from the two sessions typically differed by only a few millimeters. Coregistration of the dipoles with structural magnetic resonance images suggests that dP20m arises from an area close to the retroinsular origin of Heschl's gyrus. Although the dP20m is simply the point of steepest slope on the well-known middle-latency peak, P30m or Pam, it would appear that dP20m and P30m do not have the same cortical origin. Evidence is provided that P30m receives major contributions from at least two distinct cortical areas, only one of which is PAC. © 2002 Elsevier Science (USA)

Language: English

Document Type: Research article

DOI: 10.1006/nimg.2002.1325

Affiliations: 1: Institute of Experimental Audiology, University Clinic Münster, Münster, 48129, Germany 2: Department of Physiology, University of Cambridge, Cambridge, United Kingdom

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Localization of Primary Auditory Cortex in Humans by Magnetoencephalography