Paper Info
Title
Neural correlates of switching from auditory to speech perception.
Abstract
Many people exposed to sinewave analogues of speech first report hearing them as electronic glissando and, later, when they switch into a ‘speech mode’, hearing them as syllables. This perceptual switch modifies their discrimination abilities, enhancing perception of differences that cross phonemic boundaries while diminishing perception of differences within phonemic categories. Using high-density evoked potentials and fMRI in a discrimination paradigm, we studied the changes in brain activity that are related to this change in perception. With ERPs, we observed that phonemic coding is faster than acoustic coding: The electrophysiological mismatch response (MMR) occurred earlier for a phonemic change than for an equivalent acoustic change. The MMR topography was also more asymmetric for a phonemic change than for an acoustic change. In fMRI, activations were also significantly asymmetric, favoring the left hemisphere in both perception modes. Furthermore, switching to the speech mode significantly enhanced activation in the posterior parts of the left superior gyrus and sulcus relative to the non-speech mode. When responses to a change of stimulus were studied, a cluster of voxels in the supramarginal gyrus was activated significantly more by a phonemic change than by an acoustic change. These results demonstrate that phoneme perception in adults relies on a specific and highly efficient left-hemispheric network, which can be activated in top-down fashion when processing ambiguous speech/non-speech stimuli.
Year
DOI
Venue
2005
10.1016/j.neuroimage.2004.09.039
NeuroImage
Keywords
DocType
Volume
Speech perception,Auditory,Non-speech stimuli,ERP,MRI
Journal
24
Issue
ISSN
Citations 
1
1053-8119
36
PageRank 
References 
Authors
2.97
3
6
Name
Order
Citations
PageRank
Ghislaine Dehaene-Lambertz163364.77
Christophe Pallier218618.82
W Serniclaes3488.02
L Sprenger-Charolles4444.38
Antoinette Jobert513511.69
S Dehaene6484.58