Amplitude and frequency-modulated stimuli activate common regions of human auditory cortex

Hart, H.C., Palmer, A.R. and Hall, D.A., 2003. Amplitude and frequency-modulated stimuli activate common regions of human auditory cortex. Cerebral Cortex, 13 (7), pp. 773-781.

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Abstract

Hall et al. (Hall et al., 2002, Cerebral Cortex 12:140–149) recently showed that pulsed frequency-modulated tones generate considerably higher activation than their unmodulated counterparts in non-primary auditory regions immediately posterior and lateral to Heschl’s gyrus (HG). Here, we use fMRI to explore the type of modulation necessary to evoke such differential activation. Carrier signals were a single tone and a harmonic-complex tone, with a 300 Hz fundamental, that were modulated at a rate of 5 Hz either in frequency, or in amplitude, to create six stimulus conditions (unmodulated, FM, AM). Relative to the silent baseline, the modulated tones, in particular, activated widespread regions of the auditory cortex bilaterally along the supra-temporal plane. When compared with the unmodulated tones, both AM and FM tones generated significantly greater activation in lateral HG and the planum temporale, replicating the previous findings. These activation patterns were largely overlapping, indicating a common sensitivity to both AM and FM. Direct comparisons between AM and FM revealed a higher magnitude of activation in response to the variation in amplitude than in frequency, plus a small part of the posterolateral region in the right hemisphere whose response was specifically AM-, and not FM-, dependent. The dominant pattern of activation was that of co-localized activation by AM and FM, which is consistent with a common neural code for AM and FM within these brain regions.

Item Type: Journal article
Description: This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Cerebral Cortex following peer review. The definitive publisher-authenticated version: HART, H.C., PALMER, A.R. and HALL, D.A., 2003. Amplitude and frequency-modulated stimuli activate common regions of human auditory cortex. Cerebral Cortex, 13 (7), pp. 773-781, is available online at: http://cercor.oxfordjournals.org/cgi/content/abstract/13/7/773?ijkey=3c21bcdd05c149d0b82585b715913edff3d8a251&keytype2=tf_ipsecsha.
Publication Title: Cerebral Cortex
Creators: Hart, H.C., Palmer, A.R. and Hall, D.A.
Publisher: Oxford University Press
Date: 2003
Volume: 13
Number: 7
Rights: © 2003 Oxford University Press
Divisions: Schools > School of Social Sciences
Depositing User: EPrints Services
Date Added: 09 Oct 2015 10:08
Last Modified: 19 Oct 2015 14:28
URI: http://irep.ntu.ac.uk/id/eprint/8425

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