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White matter impairment in the speech network of individuals with autism spectrum disorder.

Peeva MG, Tourville JA, Agam Y, Holland B, Manoach DS, Guenther FH - Neuroimage Clin (2013)

Bottom Line: We found a weaker connection between the left vPMC and the supplementary motor area in the ASD group.This pathway has been hypothesized to underlie the initiation of speech motor programs.Therapies that result in normalization of this pathway may hold particular promise for improving speech output in ASD.

View Article: PubMed Central - PubMed

Affiliation: Center for Computational Neuroscience and Neural Technology, Boston University, 677 Beacon Street, Boston, MA 02215, USA.

ABSTRACT
Impairments in language and communication are core features of Autism Spectrum Disorder (ASD), and a substantial percentage of children with ASD do not develop speech. ASD is often characterized as a disorder of brain connectivity, and a number of studies have identified white matter impairments in affected individuals. The current study investigated white matter integrity in the speech network of high-functioning adults with ASD. Diffusion tensor imaging (DTI) scans were collected from 18 participants with ASD and 18 neurotypical participants. Probabilistic tractography was used to estimate the connection strength between ventral premotor cortex (vPMC), a cortical region responsible for speech motor planning, and five other cortical regions in the network of areas involved in speech production. We found a weaker connection between the left vPMC and the supplementary motor area in the ASD group. This pathway has been hypothesized to underlie the initiation of speech motor programs. Our results indicate that a key pathway in the speech production network is impaired in ASD, and that this impairment can occur even in the presence of normal language abilities. Therapies that result in normalization of this pathway may hold particular promise for improving speech output in ASD.

No MeSH data available.


Related in: MedlinePlus

Canonical tracts for the ASD and NT groups. Canonical tracts indicate voxels that contain the tract in at least 12 of 18 participants from the subject group. Coronal (left), sagittal (middle), and transverse (right) slices are provided for each group and tract; lighter shades represent voxels with higher numbers of subjects containing the tract. The bottom right panel provides a 3D view of the left SMA–vPMC tract that is impaired in ASD. L: left hemisphere. R: right hemisphere. X,Y,Z: location of the slice in the Montreal Neurological Institute coordinate frame.
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f0015: Canonical tracts for the ASD and NT groups. Canonical tracts indicate voxels that contain the tract in at least 12 of 18 participants from the subject group. Coronal (left), sagittal (middle), and transverse (right) slices are provided for each group and tract; lighter shades represent voxels with higher numbers of subjects containing the tract. The bottom right panel provides a 3D view of the left SMA–vPMC tract that is impaired in ASD. L: left hemisphere. R: right hemisphere. X,Y,Z: location of the slice in the Montreal Neurological Institute coordinate frame.

Mentions: Fig. 3 illustrates canonical tracts for each subject group formed by including only voxels that contain the tract in at least 12 of 18 subjects from that group. For the most part, the canonical tracts appear to follow the same routes in the ASD and NT groups. However, the left hemisphere SMA–vPMC canonical tract for the ASD group is visibly smaller in the 2D cross-sections (upper left panel) and 3D rendering (bottom right panel). This canonical tract had over 50% fewer voxels in the ASD group than in the NT group. This finding, combined with the finding of no significant volume differences between the individual participant's tracts in the two groups, suggests that in addition to a weaker left vPMC–SMA tract strength, ASD participants also showed more variation in the spatial location of the tract than NT participants.


White matter impairment in the speech network of individuals with autism spectrum disorder.

Peeva MG, Tourville JA, Agam Y, Holland B, Manoach DS, Guenther FH - Neuroimage Clin (2013)

Canonical tracts for the ASD and NT groups. Canonical tracts indicate voxels that contain the tract in at least 12 of 18 participants from the subject group. Coronal (left), sagittal (middle), and transverse (right) slices are provided for each group and tract; lighter shades represent voxels with higher numbers of subjects containing the tract. The bottom right panel provides a 3D view of the left SMA–vPMC tract that is impaired in ASD. L: left hemisphere. R: right hemisphere. X,Y,Z: location of the slice in the Montreal Neurological Institute coordinate frame.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3815014&req=5

f0015: Canonical tracts for the ASD and NT groups. Canonical tracts indicate voxels that contain the tract in at least 12 of 18 participants from the subject group. Coronal (left), sagittal (middle), and transverse (right) slices are provided for each group and tract; lighter shades represent voxels with higher numbers of subjects containing the tract. The bottom right panel provides a 3D view of the left SMA–vPMC tract that is impaired in ASD. L: left hemisphere. R: right hemisphere. X,Y,Z: location of the slice in the Montreal Neurological Institute coordinate frame.
Mentions: Fig. 3 illustrates canonical tracts for each subject group formed by including only voxels that contain the tract in at least 12 of 18 subjects from that group. For the most part, the canonical tracts appear to follow the same routes in the ASD and NT groups. However, the left hemisphere SMA–vPMC canonical tract for the ASD group is visibly smaller in the 2D cross-sections (upper left panel) and 3D rendering (bottom right panel). This canonical tract had over 50% fewer voxels in the ASD group than in the NT group. This finding, combined with the finding of no significant volume differences between the individual participant's tracts in the two groups, suggests that in addition to a weaker left vPMC–SMA tract strength, ASD participants also showed more variation in the spatial location of the tract than NT participants.

Bottom Line: We found a weaker connection between the left vPMC and the supplementary motor area in the ASD group.This pathway has been hypothesized to underlie the initiation of speech motor programs.Therapies that result in normalization of this pathway may hold particular promise for improving speech output in ASD.

View Article: PubMed Central - PubMed

Affiliation: Center for Computational Neuroscience and Neural Technology, Boston University, 677 Beacon Street, Boston, MA 02215, USA.

ABSTRACT
Impairments in language and communication are core features of Autism Spectrum Disorder (ASD), and a substantial percentage of children with ASD do not develop speech. ASD is often characterized as a disorder of brain connectivity, and a number of studies have identified white matter impairments in affected individuals. The current study investigated white matter integrity in the speech network of high-functioning adults with ASD. Diffusion tensor imaging (DTI) scans were collected from 18 participants with ASD and 18 neurotypical participants. Probabilistic tractography was used to estimate the connection strength between ventral premotor cortex (vPMC), a cortical region responsible for speech motor planning, and five other cortical regions in the network of areas involved in speech production. We found a weaker connection between the left vPMC and the supplementary motor area in the ASD group. This pathway has been hypothesized to underlie the initiation of speech motor programs. Our results indicate that a key pathway in the speech production network is impaired in ASD, and that this impairment can occur even in the presence of normal language abilities. Therapies that result in normalization of this pathway may hold particular promise for improving speech output in ASD.

No MeSH data available.


Related in: MedlinePlus