From Neurons to Language and Speech: An Overview

Abstract

In this chapter, we describe some of the basic principles of the human brain functionality, focusing on language and speech processes. After discussing the structure of neurons and their communication system, we delineate the functional anatomical organization of the brain. We can think of this organ as a building with multiple floors, built at different times, where the whole architecture makes sense because of the interconnections of the different floors. The lower parts of the building represent the older structures (the cerebellum, the thalamus, the limbic system, and the basal ganglia), while the upper parts are more recent (the cerebral cortex): it contains more neurons than any other cerebral structure and performs exceptional cognitive functions thanks to continuous bottom-up and top-down neural connections. In this way, the frontal, temporal, and parietal cortices were synchronized with each other—through groups (bundles) of neurons devoted to this task—and all together were synchronized with the thalamus, the limbic system, the basal ganglia, and the cerebellum. Thereby, symbolic thought, higher consciousness and language emerged. From this perspective, we discuss also how archaic structures of the brain (as the basal ganglia and cerebellum) were re-functionalized in order to mediate language processing as a result of complex synchronized ascending/descending pathways. Finally, some theoretical models that try to capture the linguistic neural organization are briefly outlined, and future perspectives of investigation and challenges are addressed.