Impaired corticostriatal connectivity in impulse control disorders in Parkinson disease

Objectives: To compare the striatum's resting-state functional connectivity in patients with Parkinson disease (PD) with and without impulse control disorders (ICDs). Methods: Twenty patients with PD and ICDs, 19 patients with PD but no ICDs, and 19 healthy controls underwent fMRI in the resting state. The ventral striatum, dorsal caudate, and anterior and posterior putamen were segmented semiautomatically. For each region of interest, a seed-based connectivity analysis was performed on preprocessed fMRI data mapped on the ipsilateral cortical surface. An additional cortical thickness analysis was used to assess and compare gray matter atrophy in the 3 study subgroups. Results: The presence of an ICD in patients with PD was associated with functional disconnection between the left anterior putamen and both the left inferior temporal gyrus and the left anterior cingulate gyrus, as well as a trend toward a functional disconnection between several motor and associative striatal regions and limbic, associative, and motor cortical regions. Patients without ICDs did not differ from healthy controls in corticostriatal connectivity. The cortical thickness analysis did not reveal any significant differences among the 3 study subgroups. Conclusions: In PD, ICDs are associated with altered connectivity between an associative striatal area (the left anterior putamen) and associative and limbic cortical regions (the left inferior temporal gyrus and the left anterior cingulate gyrus).