Right hemispheric laterality of human 40 Hz auditory steady-state responses
Hemispheric asymmetries during auditory sensory processing were examined using whole-head magnetoencephalographic recordings of auditory evoked responses to monaurally and binaurally presented amplitude-modulated sounds. Laterality indices were calculated for the transient onset responses (P1m and N1m), the transient gamma-band response, the sustained field (SF) and the 40 Hz auditory steady-state response (ASSR). All response components showed laterality toward the hemisphere contralateral to the stimulated ear. In addition, the SF and ASSR showed right hemispheric (RH) dominance. Thus, laterality of sustained response components (SF and ASSR) was distinct from that of transient responses. ASSR and SF are sensitive to stimulus periodicity. Consequently, ASSR and SF likely reflect periodic stimulus attributes and might be relevant for pitch processing based on temporal stimulus regularities. In summary, the results of the present studies demonstrate that asymmetric organization in the cerebral auditory cortex is already established on the level of sensory processing.
Ross B., Herdman A.T. & Pantev C.
online early publication March 16 2005 Author Keywords: amplitude modulation; auditory evoked magnetic fields; hemispheric asymmetry; magnetoencephalography; pitch processing KeyWords Plus: EVOKED MAGNETIC-FIELDS; WHOLE-HEAD MAGNETOENCEPHALOGRAPHY; COMPLEX TONES; HUMAN BRAIN; TONOTOPIC ORGANIZATION; FUNCTIONAL ASYMMETRY; PITCH PERCEPTION; MUSICAL TIMBRE; TEMPORAL-LOBE; CORTEX Publisher: OXFORD UNIV PRESS INC, JOURNALS DEPT, 2001 EVANS RD, CARY, NC 27513 USA Subject Category: Neurosciences IDS Number: 983FS ISSN: 1047-3211 DOI: 10.1093/cercor/bhi078