Sensorimotor and Motorsensory Interactions in Speech

A long-standing issue in psycholinguistics is whether language production and language comprehension share a common neural substrate. Recent neuroimaging studies of speech appear to support overlap of brain regions for both production and perception. However, what is not known is how to interpret the perceptual activation of motor regions. In the following, the brain regions associated with producing heard speech are described to identify the sensorimotor components of the speech motor network. The brain regions associated with speech production are then examined for their activation during passive perception of lexical items presented as heard words, pictures and printed text. A number of overlapping cortical and subcortical areas were activated during both perception and production. Interestingly, all brain areas associated with passive perception increased their activation for speech production. The increased activation in the classical sensory/perceptual areas for production suggests an interactive process in which motor areas project back to sensory/perceptual areas reflecting a binding of perception (sensory) and production (motor) regions within the network. 1