 |
|
Williams Syndrome
Neuronal Size and Neuronal-Packing Density in Primary Visual Cortex
Albert M. Galaburda, MD;
Dorothy P. Holinger, PhD;
Ursula Bellugi, EdD;
Gordon F. Sherman, PhD
Arch Neurol. 2002;59:1461-1467.
Background Williams syndrome (WMS) is a rare, genetically based syndrome associated
with a hemideletion in chromosome 7 (7q11.22-23) and characterized by a unique
constellation of somatic, brain, and cognitive features. Individuals with
WMS demonstrate an unusual and uneven neuropsychological profile showing cognitive
and visual spatial deficits juxtaposed with relative language preservation
and excellent facial recognition.
Objectives A neuroanatomical hypothesis for these behavioral findings suggests
predominant involvement of the dorsal portions of the hemispheres relative
to the ventral portions, including preferential involvement of peripheral
visual field cortical representations over central representation. Predominant
involvement of magnocellular visual pathways, as opposed to parvocellular
pathways, is also suggested by this hypothesis.
Subjects We examined primary visual cortical area 17 in the right and left hemispheres
in 6 age- and sex-matched autopsy specimens from 3 WMS-affected brains (1
male and 2 females; mean [SD] age, 44 [14] years) and 3 control brains (1
male and 2 females; mean age, 43 [11] years).
Design Neurons in layers II, III, IVA, IVB,
IVC , IVCß,
V, and VI were measured using an optical dissector method to determine possible differences
between WMS-affected and control brains in cell-packing density, neuronal
size, and neuronal size distribution.
Results We found abnormalities in peripheral visual cortex in WMS-affected brains,
but not in magnocellular subdivisions. There was a hemisphere by layer IV
interaction and a layer IV left hemisphere and diagnosis interaction in cell-packing
density. Williams syndrome–affected brains showed increased cell-packing
density in left sublayer IVCß and an excess of small neurons in left
layers IVA, IVC,
IVCß, V, and VI.
Conclusions Cell measurements differ in peripheral visual cortical fields of WMS,
with significantly smaller, more closely packed cells in some layers on the
left side. These cell-packing density and neuronal size differences may be
related to visuospatial deficits in this population.
From the Division of Behavioral Neurology, Departments of Neurology
(Drs Galaburda and Holinger) and Psychiatry (Dr Holinger), Beth Israel Deaconess
Medical Center and Harvard Medical School, Boston, Mass; Laboratory for Cognitive
Neuroscience, The Salk Institute for Biological Studies, La Jolla, Calif (Dr
Bellugi); and The Newgrange School Educational Outreach Center, Princeton,
NJ (Dr Sherman).
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati  Twitter
What's this?
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES
Retinotopically defined primary visual cortex in Williams syndrome
Olsen et al.
Brain 2009;0:awn362v1-awn362.
ABSTRACT
| FULL TEXT
Genetic Contributions to Human Gyrification: Sulcal Morphometry in Williams Syndrome
Kippenhan et al.
J. Neurosci. 2005;25:7840-7846.
ABSTRACT
| FULL TEXT
Evidence for superior parietal impairment in Williams syndrome
Eckert et al.
Neurology 2005;64:152-153.
ABSTRACT
| FULL TEXT
Anomalous brain activation during face and gaze processing in Williams syndrome
Mobbs et al.
Neurology 2004;62:2070-2076.
ABSTRACT
| FULL TEXT
An Experiment of Nature: Brain Anatomy Parallels Cognition and Behavior in Williams Syndrome
Reiss et al.
J. Neurosci. 2004;24:5009-5015.
ABSTRACT
| FULL TEXT
Williams-Beuren syndrome: a challenge for genotype-phenotype correlations
Tassabehji
Hum Mol Genet 2003;12:R229-237.
ABSTRACT
| FULL TEXT
|
