LARGE-SCALE TRACTOGRAPHY OF THE ANTERIOR LIMB OF THE INTERNAL CAPSULE: PREDICTORS OF CAPSULOTOMY OUTCOMES IN OBSESSIVE COMPULSIVE DISORDER

Objectives/Aims Surgical procedures targeting the anterior limb of the internal capsule (aLIC) can be effective in medically refractory obsessive-compulsive disorder (OCD). The aLIC consists of white-matter tracts connecting cortical and subcortical structures. Here we assess how specific aLIC tracts are affected in OCD and which tracts predicts improvement post-capsulotomy.Methods Large-scale diffusion imaging was used to compare detailed white- matter connectivity via aLIC between OCD patients (n=100) and healthy controls (n=88). For each individual, the fractional anisotropy and tract counts were calculated for each white-matterfiber bundle connecting a functionally defined prefrontal and subcortical region. Correlations between tractography measures and pre- and post- capsulotomy clinical outcomes (in obsessive-compulsive, anxiety and depression scores 6 months after surgery) were assessed in 41 …