Limits...
Atypical right hemisphere specialization for object representations in an adolescent with specific language impairment.

Brown TT, Erhart M, Avesar D, Dale AM, Halgren E, Evans JL - Front Hum Neurosci (2014)

Bottom Line: Using single-subject statistical maps of cortical activity, we compared this patient to a sibling and to a cohort of typically developing subjects during the performance of tasks designed to evoke semantic representations of concrete objects.Functional neuroanatomical differences were evident at early sensoriperceptual processing stages and continued through later cognitive stages, observed specifically at latencies typically associated with semantic encoding operations.More broadly, our results demonstrate the feasibility and potential utility of using aMEG to characterize individual patient differences in the dynamic functional organization of the brain.

View Article: PubMed Central - PubMed

Affiliation: Multimodal Imaging Laboratory, University of California San Diego , La Jolla, CA , USA ; Department of Neurosciences, School of Medicine, University of California San Diego , La Jolla, CA , USA ; Center for Human Development, University of California San Diego , La Jolla, CA , USA.

ABSTRACT
Individuals with a diagnosis of specific language impairment (SLI) show abnormal spoken language occurring alongside normal non-verbal abilities. Behaviorally, people with SLI exhibit diverse profiles of impairment involving phonological, grammatical, syntactic, and semantic aspects of language. In this study, we used a multimodal neuroimaging technique called anatomically constrained magnetoencephalography (aMEG) to measure the dynamic functional brain organization of an adolescent with SLI. Using single-subject statistical maps of cortical activity, we compared this patient to a sibling and to a cohort of typically developing subjects during the performance of tasks designed to evoke semantic representations of concrete objects. Localized patterns of brain activity within the language impaired patient showed marked differences from the typical functional organization, with significant engagement of right hemisphere heteromodal cortical regions generally homotopic to the left hemisphere areas that usually show the greatest activity for such tasks. Functional neuroanatomical differences were evident at early sensoriperceptual processing stages and continued through later cognitive stages, observed specifically at latencies typically associated with semantic encoding operations. Our findings show with real-time temporal specificity evidence for an atypical right hemisphere specialization for the representation of concrete entities, independent of verbal motor demands. More broadly, our results demonstrate the feasibility and potential utility of using aMEG to characterize individual patient differences in the dynamic functional organization of the brain.

No MeSH data available.


Related in: MedlinePlus

Group and single-subject dSPMs of mean cortical activity during the semantic processing of words. In comparison to the functional organization of both the control group and sibling, SLI-1 showed strongly right-lateralized activity, from early sensoriperceptual to later cognitive stages. His early lateral occipital response was on the opposite side and somewhat delayed in time (blue arrow) in relation to his sister (pink arrow). During latencies typically associated with semantic encoding, he showed sustained activity within right temporal, perisylvian, and frontal opercular regions (orange arrows). Color scale represents square root of F values, which are a measure of signal-to-noise.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3924145&req=5

Figure 1: Group and single-subject dSPMs of mean cortical activity during the semantic processing of words. In comparison to the functional organization of both the control group and sibling, SLI-1 showed strongly right-lateralized activity, from early sensoriperceptual to later cognitive stages. His early lateral occipital response was on the opposite side and somewhat delayed in time (blue arrow) in relation to his sister (pink arrow). During latencies typically associated with semantic encoding, he showed sustained activity within right temporal, perisylvian, and frontal opercular regions (orange arrows). Color scale represents square root of F values, which are a measure of signal-to-noise.

Mentions: Noise-normalized dSPMs for the typically developing control group were strongly consistent with the results of previous aMEG and fMRI studies of the semantic processing of words and pictures (Dale et al., 2000; Dale and Halgren, 2001; Martin and Chao, 2001; Marinkovic et al., 2003; Vigneau et al., 2006; Leonard et al., 2010, 2011; Binder and Desai, 2011). During the processing of words, early lateral visual responses occurred between 120 and 170 ms in bilateral occipitotemporal regions and were stronger on the left (Figure 1). Within 50 ms, activity spread across multiple regions bilaterally, including intraparietal and transverse occipital sulci, lateral occipitotemporal and temporal cortex, and anteriorly along perisylvian regions. By 300 ms, cortical activity became more strongly left lateralized and included left frontal operculum after about 400 ms. Qualitatively, Sib-1 showed a dynamic functional brain organization for processing words that was similar to the typically developing group. Her earliest lateral visual response occurred during 120–170 ms and was located in left middle occipital sulcus (pink arrow). Activity then spread bilaterally and anteriorly along occipitotemporal and perisylvian regions and, similar to the group, became more strongly left lateralized at 300 ms. Sustained left lateralized activity was apparent through 600 ms and at 500 ms included bilateral anterior insula and temporal poles.


Atypical right hemisphere specialization for object representations in an adolescent with specific language impairment.

Brown TT, Erhart M, Avesar D, Dale AM, Halgren E, Evans JL - Front Hum Neurosci (2014)

Group and single-subject dSPMs of mean cortical activity during the semantic processing of words. In comparison to the functional organization of both the control group and sibling, SLI-1 showed strongly right-lateralized activity, from early sensoriperceptual to later cognitive stages. His early lateral occipital response was on the opposite side and somewhat delayed in time (blue arrow) in relation to his sister (pink arrow). During latencies typically associated with semantic encoding, he showed sustained activity within right temporal, perisylvian, and frontal opercular regions (orange arrows). Color scale represents square root of F values, which are a measure of signal-to-noise.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3924145&req=5

Figure 1: Group and single-subject dSPMs of mean cortical activity during the semantic processing of words. In comparison to the functional organization of both the control group and sibling, SLI-1 showed strongly right-lateralized activity, from early sensoriperceptual to later cognitive stages. His early lateral occipital response was on the opposite side and somewhat delayed in time (blue arrow) in relation to his sister (pink arrow). During latencies typically associated with semantic encoding, he showed sustained activity within right temporal, perisylvian, and frontal opercular regions (orange arrows). Color scale represents square root of F values, which are a measure of signal-to-noise.
Mentions: Noise-normalized dSPMs for the typically developing control group were strongly consistent with the results of previous aMEG and fMRI studies of the semantic processing of words and pictures (Dale et al., 2000; Dale and Halgren, 2001; Martin and Chao, 2001; Marinkovic et al., 2003; Vigneau et al., 2006; Leonard et al., 2010, 2011; Binder and Desai, 2011). During the processing of words, early lateral visual responses occurred between 120 and 170 ms in bilateral occipitotemporal regions and were stronger on the left (Figure 1). Within 50 ms, activity spread across multiple regions bilaterally, including intraparietal and transverse occipital sulci, lateral occipitotemporal and temporal cortex, and anteriorly along perisylvian regions. By 300 ms, cortical activity became more strongly left lateralized and included left frontal operculum after about 400 ms. Qualitatively, Sib-1 showed a dynamic functional brain organization for processing words that was similar to the typically developing group. Her earliest lateral visual response occurred during 120–170 ms and was located in left middle occipital sulcus (pink arrow). Activity then spread bilaterally and anteriorly along occipitotemporal and perisylvian regions and, similar to the group, became more strongly left lateralized at 300 ms. Sustained left lateralized activity was apparent through 600 ms and at 500 ms included bilateral anterior insula and temporal poles.

Bottom Line: Using single-subject statistical maps of cortical activity, we compared this patient to a sibling and to a cohort of typically developing subjects during the performance of tasks designed to evoke semantic representations of concrete objects.Functional neuroanatomical differences were evident at early sensoriperceptual processing stages and continued through later cognitive stages, observed specifically at latencies typically associated with semantic encoding operations.More broadly, our results demonstrate the feasibility and potential utility of using aMEG to characterize individual patient differences in the dynamic functional organization of the brain.

View Article: PubMed Central - PubMed

Affiliation: Multimodal Imaging Laboratory, University of California San Diego , La Jolla, CA , USA ; Department of Neurosciences, School of Medicine, University of California San Diego , La Jolla, CA , USA ; Center for Human Development, University of California San Diego , La Jolla, CA , USA.

ABSTRACT
Individuals with a diagnosis of specific language impairment (SLI) show abnormal spoken language occurring alongside normal non-verbal abilities. Behaviorally, people with SLI exhibit diverse profiles of impairment involving phonological, grammatical, syntactic, and semantic aspects of language. In this study, we used a multimodal neuroimaging technique called anatomically constrained magnetoencephalography (aMEG) to measure the dynamic functional brain organization of an adolescent with SLI. Using single-subject statistical maps of cortical activity, we compared this patient to a sibling and to a cohort of typically developing subjects during the performance of tasks designed to evoke semantic representations of concrete objects. Localized patterns of brain activity within the language impaired patient showed marked differences from the typical functional organization, with significant engagement of right hemisphere heteromodal cortical regions generally homotopic to the left hemisphere areas that usually show the greatest activity for such tasks. Functional neuroanatomical differences were evident at early sensoriperceptual processing stages and continued through later cognitive stages, observed specifically at latencies typically associated with semantic encoding operations. Our findings show with real-time temporal specificity evidence for an atypical right hemisphere specialization for the representation of concrete entities, independent of verbal motor demands. More broadly, our results demonstrate the feasibility and potential utility of using aMEG to characterize individual patient differences in the dynamic functional organization of the brain.

No MeSH data available.


Related in: MedlinePlus