Giovanni Battistella, Dept. of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY
Although the role of the insula in speech and language is acknowledged, its specific function in the motor control of speech production remains poorly understood. I will present the main findings of a recent study aimed at examining the organization of “the insula speech network” in healthy subjects and in individuals with spasmodic dysphonia (SD), a neurological disorder selectively affecting speech production but not other vocalizations. To this end, we used probabilistic diffusion tractography to parcellate the insula based on its structural connections with Broca's area, Wernicke's area, and the laryngeal/orofacial ventral primary motor cortex, and compared the anatomical distributions of the resulting partitions between healthy subjects and SD patients. Our findings suggest a structural segregation of the parcellated insula sub-regions, which may be associated with different aspects of sensorimotor and cognitive control of speech and language, and explain the discrepancy between different lesion studies that argued for non-overlapping roles of the insula in speech and language control. Furthermore, we showed shared and distinct patterns of anatomical segregation of the insula language network in healthy subjects and SD patients, which may be associated with the different aspects of sensorimotor and cognitive control of speech in the two populations and represent an imaging marker of this speech-related disorder.