Mechanisms underlying spoken language production: facilitating frontal brain networks following aphasic stroke. . (360G-Wellcome-106161_Z_14_Z)

Word-finding difficulties (anomia) are the most common and chronically disabling impairment after aphasic stroke. However, surprisingly little is understood about the contributions that different frontal brain areas make to anomia recovery, and how these areas function together as a network. The frontal language network overlaps considerably with those supporting other diverse cognitive functions such as cognitive control; both are likely involved in language learning/recovery. Here I seek to pl ace spoken word production in the context of wider cognition and its underlying neural mechanisms to understand how common brain areas, and possibly common processes, support such disparate functions in the damaged brain. To address this I will use whole-brain high-resolution structural and functional magnetic resonance imaging (fMRI) together with high-definition transcranial direct current stimulation (HD-tDCS), plus neuropsychological examination and behavioural training of aphasic strok e patients. Using factorial neuroimaging experimental paradigms paired with 'real-life' anomia training procedures I will examine brain-behaviour relationships. My first series of experiments will use fMRI in aphasic patients both with and without damage to left frontal cortices (Broca's area). I will investigate the immediate modulatory effects of HD-tDCS on patient's residual frontal brain effective connectivity during easy and hard naming and cognitive control tasks. The second experimental series will investigate longer-term changes (consolidation) in these frontal brain networks after extended anomia training (hard becomes easy) and will correlate effective connectivity parameters with speech relearning success. This approach will provide a powerful platform to understand the neural basis of cognitive and spoken language change following brain damage.