title: Computational modeling of stuttering caused by impairments in a basal ganglia thalamo-cortical circuit involved in syllable selection and initiation.
abstract: Atypical white-matter integrity and elevated dopamine levels have been reported for individuals who stutter. We investigated how such abnormalities may lead to speech dysfluencies due to their effects on a syllable-sequencing circuit that consists of basal ganglia (BG), thalamus, and left ventral premotor cortex (vPMC). "Neurally impaired" versions of the neurocomputational speech production model GODIVA were utilized to test two hypotheses: (1) that white-matter abnormalities disturb the circuit via corticostriatal projections carrying copies of executed motor commands and (2) that dopaminergic abnormalities disturb the circuit via the striatum. Simulation results support both hypotheses: in both scenarios, the neural abnormalities delay readout of the next syllable's motor program, leading to dysfluency. The results also account for brain imaging findings during dysfluent speech. It is concluded that each of the two abnormality types can cause stuttering moments, probably by affecting the same BG-thalamus-vPMC circuit.
authors.affiliation: Center for Computational Neuroscience and Neural Technology, Boston University, 677 Beacon Street, Boston, MA 02215, United States. Electronic address: orenciv@gmail.com.
authors.forename: Oren
authors.initials: O
authors.lastname: Civier
authors.forename: Daniel
authors.initials: D
authors.lastname: Bullock
authors.forename: Ludo
authors.initials: L
authors.lastname: Max
authors.forename: Frank H
authors.initials: FH
authors.lastname: Guenther
mesh_terms: D001479:Basal Ganglia / Q000503:physiopathology; D001921:Brain / Q000503:physiopathology*; D003198:Computer Simulation; D004298:Dopamine / Q000502:physiology; D006801:Humans; D009044:Motor Cortex / Q000503:physiopathology; D009415:Nerve Net / Q000503:physiopathology; D010700:Phonetics; D013342:Stuttering / Q000503:physiopathology*; D013788:Thalamus / Q000503:physiopathology
chemical_list: D004298:Dopamine
keywords: Basal ganglia; Brain imaging; Dopamine; Neural modeling; Speech fluency; Speech motor control; Stuttering; Thalamus; Ventral premotor cortex; White matter