PB7. Comparison of three different fMRI paradigms for language mapping. Issue 8 (August 2018) - Nettekoven, C.
Abstract : Objective: Functional magnetic resonance imaging (fMRI) is widely used for mapping of language areas. However, depending on the task design and the region of interest, a clear identification of language relevant areas can be challenging. We, therefore, compared three different fMRI task designs, i.e., picture naming and listening to simple vs. complex sentences followed by a non-verbal semantic decision task, for delineating cortical language areas. Methods: 20 right-handed, healthy volunteers were investigated using fMRI (3T) with a sparse-sampling design (controlling for speech-related movement artefacts). In the first task, subjects were asked to name objects which were presented as black-white drawings by speaking out loudly a whole sentence introduced by the phrase 'That is a/an…'. In the other paradigms, subjects were listening to simple or complex sentences (spoken by a male or female voice) followed by a semantic decision task. Here, three pictures were presented 5s after the sentences and subjects were asked to choose the corresponding item via button press. FMRI activation levels corresponding to the semantic decision after listening to meaningful sentences were compared to a control condition (i.e., listening to reverse sentences). fMRI data were analyzed using SPM12. Results: The three language tasks differently activated regions engaged in the language network. Of note, listening to complex sentences led to a significantly higher activation during the semantic decision within the inferior frontal gyrus (IFG) as compared to simple sentences ( p < 0.05). Conclusion: Our results show that the activation of language-relevant areas depends strongly on the design of the fMRI task and indicate that activation within Broca's area (IFG) increases with the complexity of the semantic decision.