Left Hemispheric Dominance and the Role of Verbal Motor-Related Region in Language Cognition.
This paper discusses the cortical processing of speech recognition and the vocalization function from the results of previous PET studies, and speculates that the neuronal network encompassing the right ear, the left auditory area, and the cerebellum is engaged in accurate cognition of acquired speech, and the network of the left ear, right auditory area, and the supplementary motor area (SMA) is contributed to analyzing unknown language. A system of categorized word sounds may exist in the cerebellum, for the comparison and inspection of sound stimuli, which facilitates accurate and prompt cognition. On the other hand, for unknown speech sound, the SMA may propagate categorization of the sound input by analyzing the pattern of vocalization action.