Concordance of MEG and fMRI patterns in adolescents during verb generation

Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229-3039, USA.
Brain research (Impact Factor: 2.84). 02/2012; 1447:79-90. DOI: 10.1016/j.brainres.2012.02.001
Source: PubMed


In this study we focused on direct comparison between the spatial distributions of activation detected by functional magnetic resonance imaging (fMRI) and localization of sources detected by magnetoencephalography (MEG) during identical language tasks. We examined the spatial concordance between MEG and fMRI results in 16 adolescents performing a three-phase verb generation task that involves repeating the auditorily presented concrete noun and generating verbs either overtly or covertly in response to the auditorily presented noun. MEG analysis was completed using a synthetic aperture magnetometry (SAM) technique, while the fMRI data were analyzed using the general linear model approach with random-effects. To quantify the agreement between the two modalities, we implemented voxel-wise concordance correlation coefficient (CCC) and identified the left inferior frontal gyrus and the bilateral motor cortex with high CCC values. At the group level, MEG and fMRI data showed spatial convergence in the left inferior frontal gyrus for covert or overt generation versus overt repetition, and the bilateral motor cortex when overt generation versus covert generation. These findings demonstrate the utility of the CCC as a quantitative measure of spatial convergence between two neuroimaging techniques.

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    • "One aspect that had relevance for the design of the criteria for the evaluation of fMRI data was that we considered activations in the frontal lobe on the verb generation task and activations in the temporal lobe on the listening task to have a higher value than activations in other regions. The basis for this assumption is that the most consistently found activations of verb generation tasks are in the inferior part of the frontal lobe [46] and activations in this region were therefore considered to be highly dependable. Similarly, the listening task has been demonstrated to specifically activate the temporal lobe [17]. "
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