MEDIAL FRONTAL CORTEX IN INTENTIONAL ASPECTS OF LANGUAGE

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DESCRIPTION (Adapted from the Investigator's Abstract): Language disturbance is common in persons with brain injury and disease. The development of effective treatments for such language disturbances requires an understanding of the neurological bases of language and related functions. Intention is preparation to respond and is important for all activities, including those involving language. The literature suggests that different neural systems are engaged when intentional processes involve retrieval of information from internal knowledge stores versus when intentional processes involve simple responses to external stimuli, such as repetition. Further, the nature of information used to generate language may affect which systems are engaged to accomplish the task. The current proposal plans to explore the role and location of the medial frontal cortex involved in the intentional aspects of language expression using functional magnetic resonance imaging (fMRI). It is hypothesized that the medial frontal cortex involved in intentional language activities requiring retrieval from internal knowledge stores will be located in the dominant medial frontal gyrus, just anterior to supplementary motor area (SMA) and within the sulcus directly inferior to this cortex. This cortex is more connected to prefrontal cortex involved in action planning than SMA, which is more directly connected to motor structures. Further, this cortex is distinguishable from the limbic cortex of anterior cingulate gyrus. For repetition which involves replicating external information, it is hypothesized that SMA is involved because repetition simply requires producing the correct motor activities and sequences to replicate the stimulus. Finally, it is hypothesized that medial frontal cortex is involved in generation of language responses only when words are generated and not when meaningless syllables are generated. Eventually, the tasks and procedures involved in this study can be used to study intentional activity in patients with language impairment because of brain injury or disease.