Opposite hemispheric lateralization effects during speaking and singing at motor cortex, insula and cerebellum

TLDR

Singing is a second acoustic communication mode that, like speech, requires integration of sound structure with emotions and is supported by the insula due to its connections with premotor and limbic areas. fMRI revealed complementary hemispheric networks for singing and speaking, with singing activating the right motor cortex, right anterior insula, and left cerebellum, while speaking engaged the opposite pattern and the left insula, supporting speech articulation, whereas the right insula mediates temporo‑spatial control during singing.

Abstract

Aside from spoken language, singing represents a second mode of acoustic (auditory-vocal) communication in humans. As a new aspect of brain lateralization, functional magnetic resonance imaging (fMRI) revealed two complementary cerebral networks subserving singing and speaking. Reproduction of a non-lyrical tune elicited activation predominantly in the right motor cortex, the right anterior insula, and the left cerebellum whereas the opposite response pattern emerged during a speech task. In contrast to the hemodynamic responses within motor cortex and cerebellum, activation of the intrasylvian cortex turned out to be bound to overt task performance. These findings corroborate the assumption that the left insula supports the coordination of speech articulation. Similarly, the right insula might mediate temporo-spatial control of vocal tract musculature during overt singing. Both speech and melody production require the integration of sound structure or tonal patterns, respectively, with a speaker's emotions and attitudes. Considering the widespread interconnections with premotor cortex and limbic structures, the insula is especially suited for this task.