HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Correspondence: Submit a response Alert me when this article is cited Alert me when Correspondence are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Green, R. L. Articles by Gazzaniga, M. S. Search for Related Content PubMed PubMed Citation Articles by Green, R. L. Articles by Gazzaniga, M. S.

The caudal infrasylvian surface in dyslexia

Novel magnetic resonance imaging–based findings

From the Departments of Psychiatry (Dr. Green and A.W. Silberfarb) and Pediatrics and Neurology (Dr. Nordgren), Dartmouth Medical School, Lebanon, NH; the Center for Cognitive Neuroscience (Drs. Hutsler, Nordgren, and Gazzaniga, and C.E. Thomas), Dartmouth College, Hanover, NH; the Center for Neuroscience (W.C. Loftus), University of California, Davis, CA; and Department of Neurobiology, Harvard Medical School, Cambridge, and Cognitive/Behavioral Neurology Unit, Massachusetts General Hospital (Dr. Tramo), Boston, MA.

Address correspondence and reprint requests to Dr. Ronald L. Green, Department of Psychiatry, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, NH 03756.

OBJECTIVE: To detect anatomic abnormalities of auditory association cortex in dyslexia by measuring the area of the perisylvian region known as the caudal infrasylvian surface(s) (cIS) in dyslexic and control subjects.

BACKGROUND: Several quantitative morphometric investigations of cortical areas in dyslexia have focused on the cIS, which encompasses the supratemporal plane and the inferior bank of the posterior ascending ramus of the sylvian fissure. Inconsistencies in the results of these studies may be attributable in part to the use of measurement methods that do not account fully for surface undulations of the cIS.

METHODS: The authors used an MRI-based surface reconstruction technique that models the curvature of the cerebral cortex in three dimensions to obtain whole-hemisphere and regional surface area estimates. Measurements were obtained in both hemispheres of eight right-handed male dyslexic subjects and eight right-handed male control subjects.

RESULTS: The cIS area of dyslexic subjects was significantly larger than that of control subjects, and this result was not attributable to a difference in whole-hemisphere surface area. Neither the dyslexic nor control subjects showed a left or right asymmetry in this region, although there was a trend toward less variance of the asymmetry scores in dyslexic subjects.

CONCLUSIONS: The gross anatomic organization of this region is different in dyslexic subjects, and elucidation of the precise nature of these differences may be aided by surface modeling techniques.

Key words: Cerebral hemisphere—Brain morphology—Dyslexia—MRI.

This article has been cited by other articles:

				C. Leonard, M. Eckert, B. Given, B. Virginia, and G. Eden Individual differences in anatomy predict reading and oral language impairments in children Brain, December 1, 2006; 129(12): 3329 - 3342. [Abstract] [Full Text] [PDF]

				M. Eckert Neuroanatomical Markers for Dyslexia: A Review of Dyslexia Structural Imaging Studies Neuroscientist, August 1, 2004; 10(4): 362 - 371. [Abstract] [PDF]

				M. Habib The neurological basis of developmental dyslexia: An overview and working hypothesis Brain, December 1, 2000; 123(12): 2373 - 2399. [Abstract] [Full Text] [PDF]