Experimental Brain Research

, Volume 135, Issue 2, pp 222–230

Conscious and preconscious adaptation to rhythmic auditory stimuli: a magnetoencephalographic study of human brain responses

  • F. Tecchio
  • C. Salustri
  • M. H. Thaut
  • P. Pasqualetti
  • P. M. Rossini
Research Article

DOI: 10.1007/s002210000507

Cite this article as:
Tecchio, F., Salustri, C., Thaut, M.H. et al. Exp Brain Res (2000) 135: 222. doi:10.1007/s002210000507
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Abstract

This study was triggered by the experimental evidence that subjects required to tap in synchrony with a heard rhythm spontaneously time their tapping to variations in rhythm frequency even when these variations are so small that they are not consciously detectable. We performed a series of magnetoencephalographic (MEG) measurements, aimed at investigating whether the response of the auditory cortex discriminates randomly administered series of brief tones differing from each other only by their interstimulus intervals (ISI). Moreover, by combining psychophysical measurements, conscious and preconscious adjustments of tapping to rhythm variations were compared with brain cortical responses. The ISIs were varied by 2% or 20% from a “central” value of 500 ms. Subjects always consciously detected the 20% ISI changes and easily adjusted their tapping accordingly, whereas they never consciously detected the 2% ISI changes, even though they always correctly adjusted their tapping to them. Analysis of the auditory evoked fields (AEFs) showed that the intensity of the M100 component decreased with decreasing ISI both for 20% and 2% variations in a statistically significant manner, despite the fact that the 2% variation was not consciously perceived. The M100 behavior indicated that connections between auditory and motor cortexes may exist that are able to use the information on rhythm variations in the stimuli even when these are not consciously identified by the subject. The ability of the auditory cortex to discriminate different time characteristics of the incoming rhythmic stimuli is discussed in this paper in relation to the theories regarding the physiology of time perception and discrimination.

Key words

Rhythm perceptionAuditory evoked fieldsAuditory-motor synchronizationHuman

Copyright information

© Springer-Verlag 2000

Authors and Affiliations

  • F. Tecchio
    • 1
    • 4
  • C. Salustri
    • 1
    • 4
  • M. H. Thaut
    • 2
    • 3
    • 5
  • P. Pasqualetti
    • 4
    • 6
  • P. M. Rossini
    • 4
    • 5
    • 6
  1. 1.IESS-CNRUnita MEG-Ospedale FatebenefratelliRomeItaly
  2. 2.Department of MusicColorado State UniversityUSA
  3. 3.Department Electrical EngineeringColorado State UniversityUSA
  4. 4.FaR-Div. NeuroscienzeOspedale FatebenefratelliRomeItaly
  5. 5.IRCCS “S. Lucia”RomeItaly
  6. 6.IRCCS “S. Giovanni di Dio-F.B.F”BresciaItaly