6. Degeneracy in the neurological model of auditory speech repetition

COEX 

The neurological language model (1) posits that auditory speech repetition engages four left hemisphere brain regions sequentially: primary auditory cortex (A1), Wernicke's area (WA), Broca's area (BA), and primary motor cortex (M1), with the arcuate fasciculus mediating information relay. Recent studies challenge this, emphasising the importance of areas near WA and BA (2). Here, we investigate the bilateral interaction amongst these and their involvement with A1 and M1 during auditory speech repetition. Using previously identified activations (2) we estimate effective connectivity (i.e., directed interactions) across these areas using Dynamic Causal Modelling (DCM)3. Our findings reveal variable effective connectivity across word or pseudoword repetition, indicative of functional degeneracy.