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

Shantanu Ghosh; Amrita Basu; Senthil S Kumaran; Subash Khushu

doi:10.4103/0971-3026.69352

Indian Journal of Radiology and Imaging, Inhaltsverzeichnis

CC BY-NC-ND 4.0 · Indian J Radiol Imaging 2010; 20(03): 182-187
DOI: 10.4103/0971-3026.69352

Neuroradiology

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

Authors

Shantanu Ghosh

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

Center for Linguistics, Jawaharlal Nehru University, New Delhi 110 067, FNx01Now at Center for Cognitive Science, Jadavpur University, Kolkata 700 032, India
Senthil S Kumaran

Department of NMR, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110 029, India
Subash Khushu

NMR Research Center, Institute of Nuclear Medicine and Allied Sciences, Timarpur, Delhi 110 054, India

Abstract

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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 T2FNx01-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.

Keywords

fMRI - language network - lingual gyrus - presurgical planning - word association

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Referenzen

References
1 Binder JR, Swanson SJ, Hammeke TA, Morris GL, Mueller WM, Fischer M, et al. Determination of language dominance using functional MRI: A comparison with the Wada test. Neurology 1996;46:978-84.
2 Stippich C, Rapps N, Dreyhaupt J, Durst A, Kress B, Neonig E, et al. Localizing and lateralizing language in patients with brain tumors: feasibility of routine preoperative functional MR imaging in 81 consecutive patients. Radiology 2007;243:828-36.
3 Gabrieli JDE, Poldrack RA, Desmond JE. The role of left prefrontal cortex in language and memory. Proc Natl Acad Sci USA 1998;95:906-13.
4 Tie Y, Suarez R, Whalen S, Radmanesh A, Norton I, Golby A. Comparison of blocked and event-related fMRI designs for pre-surgical language mapping. Neuroimage 2009;47:T107-15.
5 Hagoort P. On Broca, brain, and binding: A new framework. Trends Cogn Sci 2005;9:416-23.
6 Perani D, Abutalebi J, Paulesu E, Brambati S, Scifo P, Cappa SF, et al. The role of age of acquisition and language use in early, high-proficient bilinguals: a fMRI study during verbal fluency. Hum Brain Mapp 2003;19:170-82.
7 Petersen SE, Fox PT, Posner MI, Mintun M, Raichle ME. Positron emission tomographic studies of the cortical anatomy of single-word processing. Nature 1988;331:585-9.
8 Talairach J, Tournoux P. Co-planar stereotaxic atlas of the human brain. Stuttgart: Thieme; 1988.
9 Friston KJ, Jezzard P, Turner R. Analysis of functional MRI time series. Hum Brain Mapp 1994; 1: 153-71.
10 Jezzard P, Matthews PM, Smith SM. Functional MRI: An Introduction to Methods. London: Oxford University Press; 2004.
11 Berninger VW, Richards TL. Brain Literacy for Educators and Psychologists. London: Academic Press; 2002.
12 Rugg MD, Wilding EL. Retrieval processing and episodic memory. Trends Cogn Sci 2000;4:108-15.
13 McCarthy G, Nobre AC, Bentin S, Spencer DD. Language-related field potentials in the anterior medial temporal lobe: I. Intracranial distribution and neural generators. J Neurosci 1995;15:1080-9.
14 Majerus S, Belayachi S, De Smedt B, Leclercq AL, Martinez T, Schmidt C, et al. Neural networks for short-term memory for order differentiate high and low proficiency bilinguals, Neuroimage 2008;42:1698-713.
15 Paulesu E, Frith CD, Frackowiak RSJ. The neural correlates of the verbal component of working memory. Nature 1993;362:342-5.
16 Hinojosa JA, Martνn-Loeches M, Gσmez-Jarabo G, Rubia FJ. Common basal extrastriate areas for the semantic processing of words and pictures. Clin Neurophysiol 2000;111:552-60.