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The functional anatomy of sound intensity discrimination.

Authors
  • Belin, P
  • McAdams, S
  • Smith, B
  • Savel, S
  • Thivard, L
  • Samson, S
  • Samson, Y
Type
Published Article
Journal
The Journal of neuroscience : the official journal of the Society for Neuroscience
Publication Date
Aug 15, 1998
Volume
18
Issue
16
Pages
6388–6394
Identifiers
PMID: 9698330
Source
Medline
License
Unknown

Abstract

The human neuroanatomical substrate of sound intensity discrimination was investigated by combining psychoacoustics and functional neuroimaging. Seven normal subjects were trained to detect deviant sounds presented with a slightly higher intensity than a standard harmonic sound, using a Go/No Go paradigm. Individual psychometric curves were carefully assessed using a three-step psychoacoustic procedure. Subjects were scanned while passively listening to the standard sound and while discriminating changes in sound intensity at four different performance levels (d' = 1.5, 2.5, 3.5, and 4.5). Analysis of regional cerebral blood flow data outlined activation, during the discrimination conditions, of a right hemispheric frontoparietal network already reported in other studies of selective or sustained attention to sensory input, and in which activity appeared inversely proportional to intensity discriminability. Conversely, a right posterior temporal region included in secondary auditory cortex was activated during discrimination of sound intensity independently of performance level. These findings suggest that discrimination of sound intensity involves two different cortical networks: a supramodal right frontoparietal network responsible for allocation of sensory attentional resources, and a region of secondary auditory cortex specifically involved in sensory computation of sound intensity differences.

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