Nature Neuroscience
1, 422 - 427 (1998)
doi:10.1038/1637
Analysis of temporal structure in sound by the human brainTimothy D. Griffiths1, 2, 3, Christian Büchel2, Richard S.J. Frackowiak2
& Roy D. Patterson11
Centre for the Neural Basis of Hearing, Physiology
Department, University of Cambridge, Downing Street,
Cambridge, CB2 3EG, UK
2
Wellcome Department of Cognitive Neurology, Institute
of Neurology, 12 Queen Square, London,
WC1N 3BG, UK
3
Department of Physiological Sciences, Newcastle University
Medical School, Newcastle upon Tyne, NE2 4HH,
UK
Correspondence should be addressed to Timothy D. Griffiths t.griffiths@fil.ion.ucl.ac.ukFor over a century, models of pitch perception have been based on
the frequency composition of the sound. Pitch phenomena can also be explained,
however, in terms of the time structure, or temporal regularity, of sounds.
To locate the mechanism for the detection of temporal regularity in humans,
we used functional imaging and a 'delay-and-add' noise, which activates all
frequency regions uniformly, like noise, but which nevertheless produces strong
pitch perceptions and tuneful melodies. This stimulus has temporal regularity
that can be systematically altered. We found that the activity of primary
auditory cortex increased with the regularity of the sound. Moreover, a melody
composed of delay-and-add 'notes' produced a distinct pattern of activation
in two areas of the temporal lobe distinct from primary auditory cortex. These
results suggest a hierarchical analysis of time structure in the human brain.
|
