Dynamic diaschisis: anatomically remote and context-sensitive human brain lesions.

Details

Serval ID
serval:BIB_0507C48BAAFC
Type
Article: article from journal or magazin.
Collection
Publications
Title
Dynamic diaschisis: anatomically remote and context-sensitive human brain lesions.
Journal
Journal of Cognitive Neuroscience
Author(s)
Price C.J., Warburton E.A., Moore C.J., Frackowiak R.S., Friston K.J.
ISSN
0898-929X (Print)
ISSN-L
0898-929X
Publication state
Published
Issued date
2001
Volume
13
Number
4
Pages
419-429
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov'tPublication Status: ppublish
Abstract
Functional neuroimaging was used to investigate how lesions to the Broca's area impair neuronal responses in remote undamaged cortical regions. Four patients with speech output problems, but relatively preserved comprehension, were scanned while viewing words relative to consonant letter strings. In normal subjects, this results in left lateralized activation in the posterior inferior frontal, middle temporal, and posterior inferior temporal cortices. Each patient activated normally in the middle temporal region but abnormally in the damaged posterior inferior frontal cortex and the undamaged posterior inferior temporal cortex. In the damaged frontal region, activity was insensitive to the presence of words but in the undamaged posterior inferior temporal region, activity decreased in the presence of words rather than increasing as it did in the normal individuals. The reversal of responses in the left posterior inferior temporal region illustrate the context-sensitive nature of the abnormality and that failure to activate the left posterior temporal region could not simply be accounted for by insufficient demands on the underlying function. We propose that, in normal individuals, visual word presentation changes the effective connectivity among reading areas and, in patients, posterior temporal responses are abnormal when they depend upon inputs from the damaged inferior frontal cortex. Our results serve to introduce the concept of dynamic diaschisis; the anatomically remote and context-sensitive effects of focal brain lesions. Dynamic diaschisis reveals abnormalities of functional integration that may have profound implications for neuropsychological inference, functional anatomy and, vicariously, cognitive rehabilitation.
Keywords
Aphasia, Broca/diagnosis, Aphasia, Broca/physiopathology, Behavior, Evoked Potentials, Frontal Lobe/pathology, Frontal Lobe/physiopathology, Humans, Language, Magnetic Resonance Imaging, Neuropsychological Tests, Phonetics, Reading, Reference Values, Temporal Lobe/pathology, Temporal Lobe/physiopathology, Tomography, Emission-Computed
Pubmed
Web of science
Create date
12/09/2011 19:33
Last modification date
20/08/2019 12:26
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