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Haberecht MF, Menon V, Warsofsky IS, White CD, Dyer-Friedman J, Glover GH, Neely EK, Reiss AL. Functional neuroanatomy of visuo-spatial working memory in Turner syndrome. Hum Brain Mapp 2001; 14:96-107. [PMID: 11500993 PMCID: PMC6872011 DOI: 10.1002/hbm.1044] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Turner syndrome (TS), a genetic disorder characterized by the absence of an X chromosome in females, has been associated with cognitive and visuo-spatial processing impairments. We utilized functional MRI (fMRI) to investigate the neural substrates that underlie observed deficits in executive functioning and visuo-spatial processing. Eleven females with TS and 14 typically developing females (ages 7-20) underwent fMRI scanning while performing 1-back and 2-back versions of a standard visuo-spatial working memory (WM) task. On both tasks, TS subjects performed worse than control subjects. Compared with controls, TS subjects showed increased activation in the left and right supramarginal gyrus (SMG) during the 1-back task and decreased activation in these regions during the 2-back task. In addition, decreased activation in the left and right dorsolateral prefrontal cortex (DLPFC) and caudate nucleus was observed during the 2-back task in TS subjects. Activation differences localized to the SMG, in the inferior parietal lobe, may reflect deficits in visuo-spatial encoding and WM storage mechanisms in TS. In addition, deficits in the DLPFC and caudate may be related to deficits in executive function during WM performance. Together these findings point to deficits in frontal-striatal and frontal-parietal circuits subserving multiple WM functions in TS.
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Affiliation(s)
- M F Haberecht
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California 94305, USA.
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Abstract
Williams syndrome (WMS) is a rare genetic disorder characterized by relative preservations of language ability and facial processing despite deficits in overall intelligence, problem solving, and visuospatial processing. Subjects with WMS also display hypersocial behavior and excessive linguistic affect during conversations and when giving narratives. Neuroimaging studies have shown global reductions in the brain volumes of subjects with WMS compared with normal controls, but with preservations in cerebellar volume. This study examines the neuroanatomic structure of the cerebellar vermis in 20 subjects with WMS and 20 age- and gender-matched controls via high-resolution magnetic resonance imaging. The vermis was divided into lobules I-V, VI-VII, and VIII-X. Lobules VI-VII and VIII-X were both relatively enlarged in the WMS group, and after adjusting for the smaller size of the WMS brain, the posterior vermis was significantly larger in WMS (Mann-Whitney z-value=4.27; P<0.001). Given that reductions in posterior vermis size have been implicated in flattened affect and autistic features, increased vermis size in subjects with WMS may be related to the hypersociality and heightened affective expression characteristic of individuals with this genetic condition.
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Affiliation(s)
- J E Schmitt
- Stanford Psychiatry Neuroimaging Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Road, Stanford, CA 94305-5719, USA
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Kwon H, Menon V, Eliez S, Warsofsky IS, White CD, Dyer-Friedman J, Taylor AK, Glover GH, Reiss AL. Functional neuroanatomy of visuospatial working memory in fragile X syndrome: relation to behavioral and molecular measures. Am J Psychiatry 2001; 158:1040-51. [PMID: 11431225 DOI: 10.1176/appi.ajp.158.7.1040] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Fragile X syndrome is a neurogenetic disorder that is the most common known heritable cause of neurodevelopmental disability. This study examined the neural substrates of working memory in female subjects with fragile X syndrome. Possible correlations among behavioral measures, brain activation, and the FMR1 gene product (FMRP expression), as well as between IQ and behavioral measures, were investigated. METHOD Functional magnetic resonance imaging was used to examine visuospatial working memory in 10 female subjects with fragile X syndrome and 15 typically developing female subjects (ages 10-23 years). Subjects performed standard 1-back and 2-back visuospatial working memory tasks. Brain activation was examined in four regions of the cortex known to play a critical role in visuospatial working memory. Correlations between behavioral, neuroimaging, and molecular measures were examined. RESULTS Relative to the comparison group, subjects with fragile X syndrome performed significantly worse on the 2-back task but not on the 1-back task. In a region-of-interest analysis focused on the inferior frontal gyrus, middle frontal gyrus, superior parietal lobule, and supramarginal gyrus, comparison subjects showed significantly increased brain activation between the 1-back and 2-back tasks, but subjects with fragile X syndrome showed no change in activation between the two tasks. Significant correlations were found in comparison subjects between activation in the frontal and parietal regions and the rate of correct responses on the 2-back task, but not on the 1-back task. In subjects with fragile X syndrome, significant correlations were found during the 2-back task between FMRP expression and activation in the right inferior and bilateral middle frontal gyri and the bilateral supramarginal gyri. CONCLUSIONS Subjects with fragile X syndrome are unable to modulate activation in the prefrontal and parietal cortex in response to an increasing working memory load, and these deficits are related to a lower level of FMRP expression in fragile X syndrome subjects than in normal comparison subjects. The observed correlations between biological markers and brain activation provide new evidence for links between gene expression and cognition.
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Affiliation(s)
- H Kwon
- Department of Psychiatry, Stanford University School of Medicine, CA 94305-5719, USA.
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Patwardhan AJ, Eliez S, Warsofsky IS, Glover GH, White CD, Giedd JN, Peterson BS, Rojas DC, Reiss AL. Effects of image orientation on the comparability of pediatric brain volumes using three-dimensional MR data. J Comput Assist Tomogr 2001; 25:452-7. [PMID: 11351198 DOI: 10.1097/00004728-200105000-00020] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of this study was to examine the comparability of morphometric measurements made on pediatric data sets collected at five scanner locations, each using variations on a 3D spoiled gradient-recalled echo (SPGR) pulse sequence. METHOD Archived MR data from 60 typically developing children were collected and separated into seven groups based on the pulse sequence used. A highly automated image-processing procedure was used to segment the brain data into white tissue, gray tissue, and CSF compartments and into various neuroanatomic regions of interest. RESULTS Volumetric comparisons between groups revealed differences in areas of the temporal and occipital lobes. These differences were observed when comparing data sets with different image orientations and appeared to be due to partial volume averaging (PVA) and susceptibility-induced geometric distortions. CONCLUSION Our results indicate that slice selection and image resolution should be controlled in volumetric studies using aggregated data from multiple centers to minimize the effects of PVA and susceptibility-induced geometric distortions.
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Affiliation(s)
- A J Patwardhan
- Stanford Psychiatry Neuroimaging Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, CA 94305-5719, USA
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Schmitt JE, Eliez S, Warsofsky IS, Bellugi U, Reiss AL. Corpus callosum morphology of Williams syndrome: relation to genetics and behavior. Dev Med Child Neurol 2001; 43:155-9. [PMID: 11263684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
As the largest interhemispheric commissure in the brain, the corpus callosum is of particular interest in disorders that may preferentially affect white matter development such as Williams syndrome (WS). Individuals with WS possess a remarkable array of neurobehavioral peaks and valleys, including deficits in visuospatial ability, mathematics, and attention, but with relative preservation of language and affect. Our study measured the corpus callosum and its primary subdivisions using high-resolution MRI in 20 individuals with WS (13 females and seven males; mean age 28.5, SD 8.3 years; range 19 to 44 years) and 20 age- and sex-matched control participants (mean age 28.5, SD 8.2 years; range 19 to 48 years). Total midsagittal corpus callosum area was reduced (F=4.5, p=0.04, df=36) in the WS population. The area of the splenium (F=12.4, p=0.001, df=36) and isthmus (F=9.4, p=0.004, df=36) were disproportionately reduced in WS beyond the absolute reduction of the entire corpus callosum. These reductions are in concordance with other neuroanatomical findings of decreased parietooccipital volumes as well as the observed visuospatial problems associated with WS.
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Affiliation(s)
- J E Schmitt
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, CA 94305-5719, USA
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Kates WR, Warsofsky IS, Patwardhan A, Abrams MT, Liu AM, Naidu S, Kaufmann WE, Reiss AL. Automated Talairach atlas-based parcellation and measurement of cerebral lobes in children. Psychiatry Res 1999; 91:11-30. [PMID: 10496689 DOI: 10.1016/s0925-4927(99)00011-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study applied a Talairach-based automated parcellation method, originally proposed for adults, to the measurement of lobar brain regions in pediatric study groups. Manual measures of lobar brain regions in a sample of 15 healthy boys, girls and adults were used initially to revise the original Talairach-based grid to increase its applicability to pediatric brains. The applicability of the revised Talairach grid was then tested on an independent sample of five girls with Rett syndrome. As Tables 3 and 4 in the text demonstrate, sensitivity, specificity and positive predictive values either remained unchanged or increased as a result of revising the sectors to fit the brains of children. High levels of sensitivity and specificity were achieved for all revised Talairach-based calculations in relation to the manual measures. Both positive predictive values and intraclass correlations between volumetric measures produced by the revised automated and manual methods varied with the relative size of the brain region. Values were relatively low for smaller structures such as the brainstem and subcortical region, and high for lobar regions. These results suggest that the automated Talairach atlas-based parcellation method can produce sensitive and specific volumetric measures of lobar brain regions in both normal children and children with brain disorders. Accordingly, the method holds much promise for facilitating quantitative pediatric neuroimaging research.
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Affiliation(s)
- W R Kates
- The Kennedy Krieger Institute, Baltimore, MD 21205, USA
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Kates WR, Mostofsky SH, Zimmerman AW, Mazzocco MM, Landa R, Warsofsky IS, Kaufmann WE, Reiss AL. Neuroanatomical and neurocognitive differences in a pair of monozygous twins discordant for strictly defined autism. Ann Neurol 1998; 43:782-91. [PMID: 9629848 DOI: 10.1002/ana.410430613] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study, we investigated the neuroanatomical similarities and differences between a pair of monozygotic, 7.5-year-old twin boys discordant for strictly defined autism, to identify neuroanatomical pathways that are impaired in individuals with autism. Although the unaffected twin did not fulfill the traditional diagnostic criteria for autism, he displayed constrictions in social interaction and play that were consistent with the broader phenotype for autism that has been described in nonautistic co-twins. Magnetic resonance imaging scans were obtained for each brother and compared with the scans of 5 age- and sex-matched unaffected peers. Quantitative analysis of brain anatomy revealed that the affected twin had markedly smaller caudate, amygdaloid, and hippocampal volumes, and smaller cerebellar vermis lobules VI and VII, in comparison with his brother. Both twins evidenced disproportionately reduced volumes of the superior temporal gyrus and the frontal lobe relative to the comparison sample. The results suggest the dysfunction of two separate but overlapping neuroanatomical pathways, ie, one subcortical network differentiating the twins from each other that may underlie the traditional neurobehavioral phenotype for strictly defined autism, and a second cortical network differentiating the twins from the comparison sample that may lead to the broader phenotype for autism.
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Affiliation(s)
- W R Kates
- Kennedy Krieger Institute, and Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Reiss AL, Hennessey JG, Rubin M, Beach L, Abrams MT, Warsofsky IS, Liu AM, Links JM. Reliability and validity of an algorithm for fuzzy tissue segmentation of MRI. J Comput Assist Tomogr 1998; 22:471-9. [PMID: 9606391 DOI: 10.1097/00004728-199805000-00021] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE A new multistep, volumetric-based tissue segmentation algorithm that results in fuzzy (or probabilistic) voxel description is described. This algorithm is designed to accurately segment gray matter, white matter, and CSF and can be applied to both single channel high resolution and multispectral (multiecho) MR images. METHOD The reliability and validity of this method are evaluated by assessing (a) the stability of the algorithm across time, rater, and pulse sequence; (b) the accuracy of the method when applied to both real and synthetic image datasets; and (c) differences in specific tissue volumes between individuals with a specific genetic condition (fragile X syndrome) and normal control subjects. RESULTS The algorithm was found to have high reliability, accuracy, and validity. The finding of increased caudate gray matter volume associated with the fragile X syndrome is replicated in this sample. CONCLUSION Since this segmentation approach incorporates "fuzzy" or probabilistic methods, it has the potential to more accurately address partial volume effects, anatomical variation within "pure" tissue compartments, and more subtle changes in tissue volumes as a result of disease and treatment. The method is a component of software that is available in the public domain and has been implemented on an inexpensive personal computer thus offering an attractive and promising method for determining the status and progression of both normal development and pathology of the CNS.
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Affiliation(s)
- A L Reiss
- Department of Psychiatry, Stanford University School of Medicine, CA 94305-5719, USA
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Mostofsky SH, Mazzocco MM, Aakalu G, Warsofsky IS, Denckla MB, Reiss AL. Decreased cerebellar posterior vermis size in fragile X syndrome: correlation with neurocognitive performance. Neurology 1998; 50:121-30. [PMID: 9443468 DOI: 10.1212/wnl.50.1.121] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We examined whether posterior vermis size is smaller in individuals with fragile X syndrome (fra X) than in control subjects and whether this decreased size is associated with cognitive performance. Cognitive and behavioral dysfunctions have been identified in fra X; however, underlying neuropathogenic mechanisms remain unclear. MRI was used to investigate the posterior fossa in 32 males with fra X, 28 males with other causes of cognitive disability (CD), and 38 males with normal development (ND) as well as and in 37 females with fra X and 53 female control subjects. Among females with fra X, neurocognitive correlates of posterior vermis size were examined. Posterior vermis size (cross-sectional area) in males with fra X was significantly smaller compared with CD and ND groups, particularly when corrected for intracranial area. Posterior vermis size corrected for intracranial area was significantly smaller in females with fra X compared with control subjects. Compared with males with fra X and non-fra X control subjects, posterior vermis size in females with fra X was intermediate. After statistically removing the effect of mean parental IQ, posterior vermis size predicted a significant proportion of the variance (10 to 23%) of performance on full-scale, verbal, and performance IQ; block design; categories achieved on the Wisconsin Card Sorting Test; and the Rey inventory score. The size of the posterior vermis is significantly decreased in fra X, more so in males than in females. In females with fra X, posterior vermis size predicts performance on selected cognitive measures.
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Affiliation(s)
- S H Mostofsky
- Kennedy Krieger Institute, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Kaplan DM, Liu AM, Abrams MT, Warsofsky IS, Kates WR, White CD, Kaufmann WE, Reiss AL. Application of an automated parcellation method to the analysis of pediatric brain volumes. Psychiatry Res 1997; 76:15-27. [PMID: 9498306 DOI: 10.1016/s0925-4927(97)00055-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
New techniques in quantitative imaging are needed to accelerate understanding of brain development and function in children. In this study we evaluate the reliability and validity of an automated parcellation method for the measurement of large and small brain regions in normal and developmentally disabled children. We utilized an adaptation of the Talairach atlas to semi-automatically quantify brain volumes from 10 children with fragile X syndrome, 10 age- and gender-matched controls and 10 adult controls comparing them to 'gold standard' manually delineated regions. Excellent sensitivity, specificity, intra-class correlation and positive predictive value were achieved for large structures although results were less satisfactory for smaller structures, illustrating the limits of resolution of the method. Statistically significant differences in regional brain volumes were shown between males and females, children and adults, and individuals with fragile X and matched controls. This study demonstrates an automated method which rapidly and accurately quantifies large neuroanatomical structures, but not smaller structures. This method is sufficiently accurate to demonstrate some known anatomical differences in individuals with fragile X; the results suggest that this method could be applied to the assessment of brain volume in other neurodevelopmental disabilities.
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Affiliation(s)
- D M Kaplan
- Neuroimaging Laboratory, Kennedy Krieger Institute, Baltimore, MD 21205, USA
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