Indian Journal of Radiology Indian Journal of Radiology  

   Login   | Users online: 1349

Home Bookmark this page Print this page Email this page Small font sizeDefault font size Increase font size     


NEURORADIOLOGY Table of Contents   
Year : 2010  |  Volume : 20  |  Issue : 3  |  Page : 182-187
Functional mapping of language networks in the normal brain using a word-association task

1 Behavioral and Cognitive Science Lab, Department of Humanities and Social Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016, India
2 Center for Linguistics, Jawaharlal Nehru University, New Delhi 110 067, *Now at Center for Cognitive Science, Jadavpur University, Kolkata 700 032, India
3 Department of NMR, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110 029, India
4 NMR Research Center, Institute of Nuclear Medicine and Allied Sciences, Timarpur, Delhi 110 054, India

Correspondence Address:
Shantanu Ghosh
Behavioral and Cognitive Science Lab, Department of Humanities and Social Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016
Login to access the Email id

Source of Support: Partially supported by an IIT Delhi intramural Grant # MI00523 (S.G.) and DST Grant # WOS-A/LS-177/2004 (A.B.), Conflict of Interest: None

DOI: 10.4103/0971-3026.69352

Rights and Permissions

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 90º) 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.

Print this article     Email this article

 Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
  Citation Manager
 Access Statistics
  Reader Comments
  Email Alert *
  Add to My List *
 * Requires registration (Free)

 Article Access Statistics
    PDF Downloaded338    
    Comments [Add]    
    Cited by others 4    

Recommend this journal