Functional assays of local connectivity in the somatosensory cortex of individuals with autism.
Autism Res
; 6(3): 190-200, 2013 Jun.
Article
em En
| MEDLINE
| ID: mdl-23427110
ABSTRACT
Emerging evidence for differences between individuals with autism spectrum disorder (ASD) and neurotypical (NT) individuals in somatic processing and brain response to touch suggests somatosensory cortex as a promising substrate for elucidating differences in functional brain connectivity between individuals with and without autism. Signals from adjacent digits project to neighboring locations or representations in somatosensory cortex. When a digit is stimulated, i.e. touched, its representation in cortex is directly activated; local intracortical connections indirectly activate nonprimary cortical representations corresponding to adjacent digits. The response of the nonprimary cortical representations is thus a proxy for connection strength. Local overconnectivity in autism implies that the nonprimary/primary response ratios of the ASD group will be higher than those of the NT group. D1 and D2 of the dominant hand of the participant were individually stimulated while we recorded neural responses using magnetoencephalography. The cortical representations of D1 and D2 (somatosensory-evoked fields) were computed from the ensemble-averaged data using (a) dipole model fits and (b) singular value decomposition. Individual adjacent/primary response ratios were measured, and group response ratio data were fitted with straight lines. Local overconnectivity in autism implies steeper ASD vs. NT group slopes. Our findings did not support local overconnectivity. Slopes were found to be significantly shallower for the ASD group than the NT group. Our findings support the idea of local underconnectivity in the somatosensory cortex of the brains of individuals with ASD.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Córtex Somatossensorial
/
Tato
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Transtornos Globais do Desenvolvimento Infantil
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Vias Neurais
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Adolescent
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Female
/
Humans
/
Male
Idioma:
En
Revista:
Autism Res
Assunto da revista:
PSIQUIATRIA
/
TRANSTORNOS MENTAIS
Ano de publicação:
2013
Tipo de documento:
Article