Multistable representation of speech forms: a functional MRI study of verbal transformations.
We used functional magnetic resonance imaging (fMRI) to localize the brain areas involved in the imagery analogue of the verbal transformation effect, that is, the perceptual changes that occur when a speech form is cycled in rapid and continuous mental repetition. Two conditions were contrasted: a baseline condition involving the simple mental repetition of speech sequences, and a verbal transformation condition involving the mental repetition of the same items with an active search for verbal transformation. Our results reveal a predominantly left-lateralized network of cerebral regions activated by the verbal transformation task, similar to the neural network involved in verbal working memory: the left inferior frontal gyrus, the left supramarginal gyrus, the left superior temporal gyrus, the anterior part of the right cingulate cortex, and the cerebellar cortex, bilaterally. Our results strongly suggest that the imagery analogue of the verbal transformation effect, which requires percept analysis, form interpretation, and attentional maintenance of verbal material, relies on a working memory module sharing common components of speech perception and speech production systems.
Sato
Marc
M
Institut de la Communication Parlée, CNRS UMR 5009, Institut National Polytechnique de Grenoble, Université Stendhal 46, Avenue Félix Viallet, 38031 Grenoble Cedex 01-France. sato@icp.inpg.fr
Baciu
Monica
M
Loevenbruck
Hélène
H
Schwartz
Jean-Luc
JL
Cathiard
Marie-Agnès
MA
Segebarth
Christoph
C
Abry
Christian
C
D000328:Adult; D001921:Brain / Q000502:physiology*; D017352:Echo-Planar Imaging; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D015233:Models, Statistical; D011597:Psychomotor Performance / Q000502:physiology; D013060:Speech / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology*