Fronto-temporal mapping and connectivity using NIRS for language-related paradigms

NIRS studies were performed on 15 normal right-handed adults to understand the hemodynamic response of the fronto-temporal cortex in response to language paradigms. A 32-channel NIRS system (Imagent ISS Inc.) was used to perform NIRS studies in response to word expression and word reception language paradigms. Activation, functional connectivity, and lateralization analyses were carried out and correlated across all subjects and for each paradigm/stimuli. It was observed that Broca's region plays a major role and Wernicke's region plays a supporting role when responding to word expression paradigm (as observed in past NIRS studies). On the contrary, it is the right homolog of Wernicke's (and partly right homolog of Broca's region) that plays a major role during word reception of comprehensible text (as observed from fMRI studies). This is the first NIRS study that images the entire fronto-temporal regions to understand language from various analyses, towards future work in epileptic/schizophrenic populations.

► First NIRS study to map entire fronto-temporal cortex for language. ► Activation, functional connectivity and lateralization studies performed. ► Left anterior fronto-temporal region responsible for word generation. ► Right anterior fronto-temporal region is responsible for word reception. ► Consistency in NIRS results in comparison to clinically available fMRI.