A Double-Blind Study Assessing the Impact of Orbitofrontal Theta Burst Stimulation on Goal-Directed Behavior

SOURCE: Journal of Psychopathology and Clinical Science. 131(3):287-300, 2022 Apr.

AUTHORS: Brown VM; Gillan CM; Renard M; Kaskie R; Degutis M; Wears A; Siegle GJ; Ferrarelli F; Ahmari SE; Price RB

ABSTRACT: Patients with disorders of compulsivity show impairments in goal-directed behavior, which have been linked to orbitofrontal cortex (OFC) dysfunction. We recently showed that continuous theta burst stimulation (cTBS), which reduces OFC activity, had a beneficial effect on compulsive behaviors both immediately and at 1 week follow-up compared with inhibitory TBS (iTBS). In this same sample, we investigated whether two behavioral measures of goal-directed control (devaluation success on a habit override task; model-based planning on the two-step task) were also affected by acute modulation of OFC activity. Overall, model-based planning and devaluation success were significantly related to each other and (for devaluation success) to symptoms in our transdiagnostic clinical
sample. These measures were moderately to highly stable across time. In individuals with low levels of model-based planning, active cTBS improved devaluation success. Analogous to previously reported clinical effects, this effect was specific to cTBS and not iTBS. Overall, results suggested that measures of goal directed behavior are reliable but less affected by cTBS than clinical self-report. Future research should continue to examine longitudinal changes in behavioral measures to determine their temporal relationship with symptom improvement after treatment.