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Functional mapping of language networks in the normal brain using a word-association task.

Ghosh S, Basu A, Kumaran SS, Khushu S - Indian J Radiol Imaging (2010)

Bottom Line: Single subject analysis of the functional data (FWE-corrected, P≤0.001) revealed extensive activation in the frontal lobes, with overlaps among middle frontal gyrus (MFG), superior, and inferior frontal gyri.BOLD activity was also found in the medial frontal gyrus, middle occipital gyrus (MOG), anterior fusiform gyrus, superior and inferior parietal lobules, and to a smaller extent, the thalamus and right anterior cerebellum.Group analysis (FWE-corrected, P≤0.001) revealed neural recruitment of bilateral lingual gyri, left MFG, bilateral MOG, left superior occipital gyrus, left fusiform gyrus, bilateral thalami, and right cerebellar areas.

View Article: PubMed Central - PubMed

Affiliation: Behavioral and Cognitive Science Lab, Department of Humanities and Social Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016 India.

ABSTRACT

Background: Language functions are known to be affected in diverse neurological conditions, including ischemic stroke, traumatic brain injury, and brain tumors. Because language networks are extensive, interpretation of functional data depends on the task completed during evaluation.

Aim: The aim was to map the hemodynamic consequences of word association using functional magnetic resonance imaging (fMRI) in normal human subjects.

Materials and methods: Ten healthy subjects underwent fMRI scanning with a postlexical access semantic association task vs lexical processing task. The fMRI protocol involved a T2*-weighted gradient-echo echo-planar imaging (GE-EPI) sequence (TR 4523 ms, TE 64 ms, flip angle 90°) with alternate baseline and activation blocks. A total of 78 scans were taken (interscan interval = 3 s) with a total imaging time of 587 s. Functional data were processed in Statistical Parametric Mapping software (SPM2) with 8-mm Gaussian kernel by convolving the blood oxygenation level-dependent (BOLD) signal with an hemodynamic response function estimated by general linear method to generate SPM{t} and SPM{F} maps.

Results: Single subject analysis of the functional data (FWE-corrected, P≤0.001) revealed extensive activation in the frontal lobes, with overlaps among middle frontal gyrus (MFG), superior, and inferior frontal gyri. BOLD activity was also found in the medial frontal gyrus, middle occipital gyrus (MOG), anterior fusiform gyrus, superior and inferior parietal lobules, and to a smaller extent, the thalamus and right anterior cerebellum. Group analysis (FWE-corrected, P≤0.001) revealed neural recruitment of bilateral lingual gyri, left MFG, bilateral MOG, left superior occipital gyrus, left fusiform gyrus, bilateral thalami, and right cerebellar areas.

Conclusions: Group data analysis revealed a cerebellar-occipital-fusiform-thalamic network centered around bilateral lingual gyri for word association, thereby indicating how these areas facilitate language comprehension by activating a semantic association network of words processed postlexical access. This finding is important when assessing the extent of cognitive damage and/or recovery and can be used for presurgical planning after optimization.

No MeSH data available.


Related in: MedlinePlus

MRI images (A) show the cortical activation pattern for the whole sample for postlexical access semantic association task. Functional scans were done in a 1.5-T whole-body scanner and overlaid on an SPM anatomical template. Surface rendering of cortical activation for word concept association for all subjects for the right (B) and left (C) hemispheres (FWE-corrected, P≤0.001).
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Figure 0001: MRI images (A) show the cortical activation pattern for the whole sample for postlexical access semantic association task. Functional scans were done in a 1.5-T whole-body scanner and overlaid on an SPM anatomical template. Surface rendering of cortical activation for word concept association for all subjects for the right (B) and left (C) hemispheres (FWE-corrected, P≤0.001).

Mentions: Group analysis (FWE-corrected, P≤0.001) revealed a pattern of neural recruitment that is centered around the lingual gyri bilaterally, middle occipital and fusiform gyri, and the thalamic region. The Montreal Neurological Institute coordinates of the significant activation sites found in the group analysis of the sample is depicted in Table 1 (Figure 1A depicts the functional activations overlaid on anatomical template image for all subjects pooled together, and Figure 1B and C illustrate cortical rendering of the same data in the right and left hemispheres). We found that the lingual gyri bilaterally are activated along with the left MFG, the middle occipital gyri bilaterally, left superior occipital gyrus, left fusiform gyrus, both thalami, and the right cerebellar areas to effect postlexical access semantic association.


Functional mapping of language networks in the normal brain using a word-association task.

Ghosh S, Basu A, Kumaran SS, Khushu S - Indian J Radiol Imaging (2010)

MRI images (A) show the cortical activation pattern for the whole sample for postlexical access semantic association task. Functional scans were done in a 1.5-T whole-body scanner and overlaid on an SPM anatomical template. Surface rendering of cortical activation for word concept association for all subjects for the right (B) and left (C) hemispheres (FWE-corrected, P≤0.001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2963756&req=5

Figure 0001: MRI images (A) show the cortical activation pattern for the whole sample for postlexical access semantic association task. Functional scans were done in a 1.5-T whole-body scanner and overlaid on an SPM anatomical template. Surface rendering of cortical activation for word concept association for all subjects for the right (B) and left (C) hemispheres (FWE-corrected, P≤0.001).
Mentions: Group analysis (FWE-corrected, P≤0.001) revealed a pattern of neural recruitment that is centered around the lingual gyri bilaterally, middle occipital and fusiform gyri, and the thalamic region. The Montreal Neurological Institute coordinates of the significant activation sites found in the group analysis of the sample is depicted in Table 1 (Figure 1A depicts the functional activations overlaid on anatomical template image for all subjects pooled together, and Figure 1B and C illustrate cortical rendering of the same data in the right and left hemispheres). We found that the lingual gyri bilaterally are activated along with the left MFG, the middle occipital gyri bilaterally, left superior occipital gyrus, left fusiform gyrus, both thalami, and the right cerebellar areas to effect postlexical access semantic association.

Bottom Line: Single subject analysis of the functional data (FWE-corrected, P≤0.001) revealed extensive activation in the frontal lobes, with overlaps among middle frontal gyrus (MFG), superior, and inferior frontal gyri.BOLD activity was also found in the medial frontal gyrus, middle occipital gyrus (MOG), anterior fusiform gyrus, superior and inferior parietal lobules, and to a smaller extent, the thalamus and right anterior cerebellum.Group analysis (FWE-corrected, P≤0.001) revealed neural recruitment of bilateral lingual gyri, left MFG, bilateral MOG, left superior occipital gyrus, left fusiform gyrus, bilateral thalami, and right cerebellar areas.

View Article: PubMed Central - PubMed

Affiliation: Behavioral and Cognitive Science Lab, Department of Humanities and Social Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016 India.

ABSTRACT

Background: Language functions are known to be affected in diverse neurological conditions, including ischemic stroke, traumatic brain injury, and brain tumors. Because language networks are extensive, interpretation of functional data depends on the task completed during evaluation.

Aim: The aim was to map the hemodynamic consequences of word association using functional magnetic resonance imaging (fMRI) in normal human subjects.

Materials and methods: Ten healthy subjects underwent fMRI scanning with a postlexical access semantic association task vs lexical processing task. The fMRI protocol involved a T2*-weighted gradient-echo echo-planar imaging (GE-EPI) sequence (TR 4523 ms, TE 64 ms, flip angle 90°) with alternate baseline and activation blocks. A total of 78 scans were taken (interscan interval = 3 s) with a total imaging time of 587 s. Functional data were processed in Statistical Parametric Mapping software (SPM2) with 8-mm Gaussian kernel by convolving the blood oxygenation level-dependent (BOLD) signal with an hemodynamic response function estimated by general linear method to generate SPM{t} and SPM{F} maps.

Results: Single subject analysis of the functional data (FWE-corrected, P≤0.001) revealed extensive activation in the frontal lobes, with overlaps among middle frontal gyrus (MFG), superior, and inferior frontal gyri. BOLD activity was also found in the medial frontal gyrus, middle occipital gyrus (MOG), anterior fusiform gyrus, superior and inferior parietal lobules, and to a smaller extent, the thalamus and right anterior cerebellum. Group analysis (FWE-corrected, P≤0.001) revealed neural recruitment of bilateral lingual gyri, left MFG, bilateral MOG, left superior occipital gyrus, left fusiform gyrus, bilateral thalami, and right cerebellar areas.

Conclusions: Group data analysis revealed a cerebellar-occipital-fusiform-thalamic network centered around bilateral lingual gyri for word association, thereby indicating how these areas facilitate language comprehension by activating a semantic association network of words processed postlexical access. This finding is important when assessing the extent of cognitive damage and/or recovery and can be used for presurgical planning after optimization.

No MeSH data available.


Related in: MedlinePlus