Papers by Eric Courchesne
Research Square (Research Square), Sep 8, 2020
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Neurology, Feb 1, 1994
Magnetic resonance imaging (MRI) is a powerful tool for investigating neurologic disorders for wh... more Magnetic resonance imaging (MRI) is a powerful tool for investigating neurologic disorders for which etiology is not yet resolved. Macroscopic neuroanatomic differences detectable by MRI complement microscopic findings from autopsy. One disorder for which this is true is infantile autism. Several researchers have used MRI to investigate the neuroanatomy of autistic subjects in search of abnormalities that may underlie the social, language, and cognitive dysfunction characteristic of the disorder. To date, substantial evidence from MRI and autopsy shows abnormalities in the cerebellum.l-ll However, a few studies have reported negative r e s ~ l t s . l ~ ~ ~ In this issue of Neurology, we present a metaanalysis of MRI measurements of the cerebellar vermis in autism from recent studies, including those reporting negative findings.’6J7 This meta-analysis combines data from separate laboratories to reveal a bimodal distribution in cerebellar vermis measures, which supports the hypothesis that there are at least two distinct subtypes of abnormality and provides a possible explanation for the conflicting results. The process of reconciling discrepancies among studies forced us to carefully consider the methodologic features employed in MRI studies of autism. In part to explain the contradictory results, and, more importantly, to offer guidelines for future studies, we have identified several critical issues that must enter decisions when planning research designs to accomplish specific goals in any MRI studies of neurologic disorders. Shrewdly made design choices greatly increase the probability of obtaining results consistent with these goals.
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Pediatrics, Apr 1, 2001
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Brain Research, Aug 1, 2007
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Biological Psychiatry, Sep 1, 2004
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Journal of Cognitive Neuroscience, 1994
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Cognitive Brain Research, Aug 1, 2002
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Cerebral Cortex, 1992
ABSTRACT
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Biological Psychiatry, Aug 1, 2004
The cerebellum is one of the most consistent sites of neuroanatomic abnormality in autism, yet it... more The cerebellum is one of the most consistent sites of neuroanatomic abnormality in autism, yet it is still unclear how such pathology impacts cerebellar function. In normal subjects, we previously demonstrated with functional magnetic resonance imaging (fMRI) a dissociation between cerebellar regions involved in attention and those involved in a simple motor task, with motor activation localized to the anterior cerebellum ipsilateral to the moving hand. The purpose of the present investigation was to examine activation in the cerebella of autistic patients and normal control subjects performing this motor task. We studied eight autistic patients and eight matched normal subjects, using fMRI. An anatomic region-of-interest approach was used, allowing a detailed examination of cerebellar function. Autistic individuals showed significantly increased motor activation in the ipsilateral anterior cerebellar hemisphere relative to normal subjects, in addition to atypical activation in contralateral and posterior cerebellar regions. Moreover, increased activation was correlated with the degree of cerebellar structural abnormality. These findings strongly suggest dysfunction of the autistic cerebellum that is a reflection of cerebellar anatomic abnormality. This neurofunctional deficit might be a key contributor to the development of certain diagnostic features of autism (e.g., impaired communication and social interaction, restricted interests, and stereotyped behaviors).
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Current Opinion in Neurology, Aug 1, 2004
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International Journal of Developmental Neuroscience, Feb 21, 2005
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Proceedings of the National Academy of Sciences of the United States of America, May 23, 2006
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Molecular Autism, Jun 21, 2017
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The Journal of Pediatrics, Sep 1, 2016
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Development and Psychopathology, Aug 20, 2002
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Brain Research, May 1, 2012
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The Journal of Neuroscience, Jul 1, 1999
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NeuroImage, Dec 1, 2013
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Pediatrics, May 1, 1991
In the last decade, neuroimaging research has established that neuroanatomical abnormalities ofte... more In the last decade, neuroimaging research has established that neuroanatomical abnormalities often occur in autistic individuals, but no single type of reported abnormality is ubiquitous in autism. Abnormalities in cerebral cortex, thalamus, basal ganglia, and brainstem have been inconsistently found or infrequently reported, but definitive studies remain to be done. Enlargement of cerebrospinal fluid spaces is present in some autistic people.1-10 One of the most frequently found abnormalities in autism with and without mental retardation is a reduction of cerebellar tissue.1,2,4,5,11-22 The reduction in cerebellar tissue appears to be greatest in neocerebellar regions within the vermis and hemispheres.4,11,12,15,16,18-22 The reduction appears to be the result of developmental hypoplasia rather than damage following full development, and so it may serve as a temporal marker to identify the events that damage the developing brain in autism, including other neural structures that may be concomitantly damaged.11 CEREBRAL HEMISPHERES, THALMUS, BASAL GANGLIA, AND LATERAL AND THIRD VENTRICLES Quantitative Imaging Studies Early quantitative computed tomography (CT) studies reported unusual parietooccipital and frontal asymmetries in autistic patients.23 Fourteen recent CT and magnetic resonance (MR) studies involving 283 autistic subjects have quantitated the size, volume, night-left asymmetry, and radio density on signal intensity of either the cerebral hemispheres, thalamus, basal ganglia, limbic structures, lateral ventricles, or third ventricle (Tables 1 and 2). In addition, these structures have been microscopically examined at autopsy in several cases of autism (Table 1). As seen in Tables 1 and 2, in quantitative neuroimaging studies there is no substantial evidence of abnormality in the cerebral hemispheres, corpus callosum, thalamus, basal ganglia, brain volume, lateral ventricles, and third ventricles.
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International Review of Neurobiology, 1997
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Papers by Eric Courchesne