Accession Number : ADP006083

Title :   Neuromagnetic Evidence of Place Mechanisms for Frequency and Intensity Coding in the Human Auditory Cortex,

Corporate Author : MUENSTER UNIV (GERMANY F R)

Personal Author(s) : Hoke, M. ; Pantew, C. ; Lehnertz, K. ; Luetkenhoener, B.

Report Date : FEB 1988

Pagination or Media Count : 12

Abstract : The influence of two decisive parameters of the acoustic stimulus - frequency and intensity - on the auditory evoked magnetic field in response to tone-burst stimulation was investigated in four normal-hearing subjects. The influence was quantified in terms of changes of the parameters of an equivalent current dipole (spatial coordinates, direction, and strength). The frequency dependence was investigated by varying the carrier frequency of the tone-burst between 250 and 4000 Hz in octave steps with the intensity kept constant at 60 dB HL, while the intensity dependence was investigated by varying the intensity of a 1000 Hz tone-burst between 30 and 80 dB HL in 10 dB steps. The parameters of an equivalent current dipole (ECD) were determined such that a maximum correspondence between observed and calculated field distribution (semi-infinite volume model) was obtained. The main results are as follows: The location of the ECD changes significantly as a function of test frequency and intensity. Especially the depth increases with the logarithm of test frequency which proves that also in humans the tonotopic organization of the cochlea is maintained in the auditory cortex. (js)

Descriptors :   *SPATIAL DISTRIBUTION, ACOUSTICS, CARRIER FREQUENCIES, COCHLEA, CODING, COORDINATES, DEPTH, DISTRIBUTION, FREQUENCY, HEARING, HUMANS, INTENSITY, LOGARITHM FUNCTIONS, MAGNETIC FIELDS, MODELS, ORGANIZATIONS, STIMULI, TEST AND EVALUATION, VOLUME.

Subject Categories : Psychology

Distribution Statement : APPROVED FOR PUBLIC RELEASE