Neural regions associated with categorical speech perception and production

Abstract

Speech perception and production have been characterized as categorical processes. In this paper, I present neuropsychological and neuroimaging evidence that supports the idea that speech processes are categorical as well as discussing what types of representations are important in perception and production tasks. It has become increasingly clear that both prefrontal and temporal-parietal regions are critical for perceiving phonemes categorically and producing phonemes that are good exemplars of a given phonemic category. I suggest that motor speech representations are important for both perception and production and that these are most probably housed in the prefrontal cortex. Moreover, information about acoustic features associated with phonemes almost certainly resides in more posterior cortices. Whereas these cortical regions are thought to maintain motor or acoustic information necessary for successful categorical perception and production, other regions such as the cerebellum can indirectly affect these abilities. Although speech perception and production appear effortless, these abilities rely on intact functioning of a large network of neural regions.