The cortical organization of speech processing
Despite decades of research, the functional neuroanatomy of speech processing has been difficult to characterize. A major impediment to progress may have been the failure to consider task effects when mapping speech related processing systems. We outline a dual stream model of speech processing that remedies this situation. In this model, a ventral stream processes speech signals for comprehension, and a dorsal stream maps acoustic speech signals to frontal lobe articulatory networks. The model assumes that the ventral stream is largely bilaterally organized although there are important computational differences between the left and right hemisphere systems and that the dorsal stream is strongly left hemisphere dominant.
Nature Reviews Neuroscience