The loss of asymmetry and reduced interhemispheric connectivity in adolescents with autism: A study using diffusion spectrum imaging tractography

Lo, Yu Chun; Soong, Wei Tsuen; Gau, Susan Shur‐Fen; Wu, Yu Yu; Lai, Meng‐Chuan; Yeh, Fang‐Cheng; Chiang, Wen Yang; Kuo, Li Wei; Jaw, Fu Shan; Tseng, Wen‐Yih Isaac

doi:10.1016/j.pscychresns.2010.09.008

Cited by 112 publications

(102 citation statements)

References 57 publications

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“…This role for Tbr1 in callosal development is also intriguing in the context of autism. Autistic patients seem to have callosal abnormalities (19)(20)(21)(22)(23)(24)(25)(26), and in this context it is relevant that Auts2, a gene associated with autism, is regulated by Tbr1, which in turn is regulated by Satb2, a callosal fate specification gene. Recent studies suggest that a mutation in CAv1/2 (an L-type calcium channel) that is associated with Timothy syndrome, a form of autism, results in lower numbers of Satb2-expressing cells and an increase in Ctip2-expressing cells (31).…”

Section: Discussionmentioning

confidence: 99%

“…The functional significance of this relationship has been puzzling because Tbr1 regulates corticothalamic identity, and there have been no reports of defects in corticothalamic tracts in autistic patients. However, imaging studies in patients with autism have revealed defects in callosal tracts (2,(19)(20)(21)(22)(23)(24)(25)(26). A recent publication highlights a deficit in long-range connections (such as callosal connections) and excess of short-range cortical connections in patients with autism spectrum disorder (27).…”

Section: Loss Of Tbr1 Expression In Satb2 Mutants Coincides With a Lomentioning

confidence: 99%

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A network of genetic repression and derepression specifies projection fates in the developing neocortex

Srinivasan

Leone

Bateson

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

159

171

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Neurons within each layer in the mammalian cortex have stereotypic projections. Four genes-Fezf2, Ctip2, Tbr1, and Satb2-regulate these projection identities. These genes also interact with each other, and it is unclear how these interactions shape the final projection identity. Here we show, by generating double mutants of Fezf2, Ctip2, and Satb2, that cortical neurons deploy a complex genetic switch that uses mutual repression to produce subcortical or callosal projections. We discovered that Tbr1, EphA4, and Unc5H3 are critical downstream targets of Satb2 in callosal fate specification. This represents a unique role for Tbr1, implicated previously in specifying corticothalamic projections. We further show that Tbr1 expression is dually regulated by Satb2 and Ctip2 in layers 2-5. Finally, we show that Satb2 and Fezf2 regulate two disease-related genes, Auts2 (Autistic Susceptibility Gene2) and Bhlhb5 (mutated in Hereditary Spastic Paraplegia), providing a molecular handle to investigate circuit disorders in neurodevelopmental diseases.cell fate | cerebral cortex | axon guidance | transcription factor

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Section: Discussionmentioning

confidence: 99%

Section: Loss Of Tbr1 Expression In Satb2 Mutants Coincides With a Lomentioning

confidence: 99%

A network of genetic repression and derepression specifies projection fates in the developing neocortex

Srinivasan

Leone

Bateson

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

159

171

View full text Add to dashboard Cite

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“…8,9 DSI tractography has been successfully applied to examine the microstructural integrity of major fiber pathways such as the CC, arcuate fasciculus, cingulum bundle, and CST in various neurologic or mental diseases. [10][11][12][13] With the advantage of DSI, our study performed a tractography-based analysis for reliable tract-to-tract comparisons and aimed to establish the pattern of white matter degeneration of ARHSP-TCC.…”

mentioning

confidence: 99%

“…To perform tractography reconstruction objectively, we used an expert-monitored multiple region-of-interest strategy with whole-brain seeding. 12 To do this, we coregistered each individual's DSI dataset to his or her own T2-weighted MR images by 3D affine transform. T2-weighted images of each subject were mapped to a standard Montreal Neurological Institute template by 3D nonlinear transform.…”

mentioning

confidence: 99%

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Microstructural Integrity of Cerebral Fiber Tracts in Hereditary Spastic Paraparesis withSPG11Mutation

Pan¹,

Huang

et al. 2012

AJNR Am J Neuroradiol

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Pervasive Rightward Asymmetry Shifts of Functional Networks in Autism Spectrum Disorder

Cardinale¹,

Shih²,

Fishman³

et al. 2013

JAMA Psychiatry

124

107

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utism spectrum disorder (ASD) is characterized by sociocommunicative impairments, repetitive behaviors, and restricted interests. 1 While viewed as a neurological disorder, its precise neural bases are not well understood. Growing evidence suggests that sociocommunicative, cognitive, and sensorimotor impairments are related to abnormalities of distributed networks, rather than of single brain loci. [2][3][4] Reports of atypical hemispheric asymmetries in ASD come from anatomical [5][6][7] and functional imaging studies. [8][9][10][11][12] Eyler and colleagues 13 observed atypical rightward asymmetry of receptive language activations during natural sleep in infants down to age 12.5 months, indicating that abnormal lateralization may predate language acquisition. However, all of the studies cited above focused on brain regions or stimuli specifically related to language. A recent study on gene expression in post mortem frontal cortex showed abnormalities in patterning pathways affecting lateralization in ASD, 14 possibly suggesting a broader impact on asymmetries even outside the language domain. While far from conclusive, these intriguing findings prompt the question whether atypical asymmetry could be a fundamental feature of brain organization in ASD. Indeed, theoretical considerations about possible left-hemisphere dysfunction 15,16 or, alternatively, predominant righthemisphere impairment 17,18 have a long history in autism research. However, these conjectures were largely based on limited behavioral findings, and conclusive imaging evidence beyond the language domain is lacking. Functional asymmetries related to nonverbal processing in ASD have received little attention, with only 2 studies reporting atypical left-hemisphere processing for motor tasks. 19,20 Moreover, functional studies have typically applied a priori models of task-driven activation effects. Since ASD is a pervasive developmental disorder whose neurofunctional bases are not well understood, hypothesis-driven approaches targeting single domains may, however, fail to provide comprehensive evidence because unexpected abnormalities may be missed.IMPORTANCE Autism spectrum disorder (ASD) is a brain-based pervasive developmental disorder, which-by growing consensus-is associated with abnormal organization of functional networks. Several previous studies of ASD have indicated atypical hemispheric asymmetries for language.OBJECTIVE To examine the asymmetry of functional networks using a data-driven approach for a comprehensive investigation of hemispheric asymmetry in ASD. DESIGN, SETTING, AND PARTICIPANTSThis cross-sectional study involved 24 children with ASD and 26 matched typically developing children at

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The loss of asymmetry and reduced interhemispheric connectivity in adolescents with autism: A study using diffusion spectrum imaging tractography

Cited by 112 publications

References 57 publications

A network of genetic repression and derepression specifies projection fates in the developing neocortex

A network of genetic repression and derepression specifies projection fates in the developing neocortex

Microstructural Integrity of Cerebral Fiber Tracts in Hereditary Spastic Paraparesis withSPG11Mutation

Pervasive Rightward Asymmetry Shifts of Functional Networks in Autism Spectrum Disorder

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