Background and Objectives: Laryngeal dystonia (LD) is isolated task-specific focal dystonia selectively impairing speech production. The first choice of LD treatment is botulinum neurotoxin (BoNT) injections into the affected laryngeal muscles. However, whether BoNT has a lasting therapeutic effect on disorder pathophysiology is unknown. We investigated short- and long-term effects of BoNT treatment on brain function in LD patients. Methods: A total of 161 subjects participated in the functional MRI study. Statistical analyses examined central BoNT effects in LD patients who were stratified based on the effectiveness and duration of treatment. Results: LD patients who were treated and benefited from BoNT injections had reduced activity in the left precuneus compared to BoNT-naïve and treatment non-benefiting patients. Additionally, BoNT-treated patients with adductor LD had decreased activity in the right thalamus, whereas BoNT-treated abductor LD patients had reduced activity in the left inferior frontal cortex. No statistically significant differences in brain activity were found between patients with shorter (1-5 years) and longer (13-28 years) treatment durations. However, patients with intermediate treatment duration of 6 to 12 years showed reduced activity in the right cerebellum compared to patients with both shorter and longer treatment durations and reduced activity in the right prefrontal cortex compared to patients with shorter treatment duration. Discussion: Our findings suggest that the left precuneus is the site of short-term BoNT central action in LD patients, whereas the prefrontal-cerebellar axis is engaged in the BoNT response in patients with intermediate treatment duration of 6-12 years. Involvement of these structures points to indirect action of BoNT treatment on the dystonic sensorimotor network via modulation of speech motor sequence planning and coordination.