Deep brain stimulation (DBS), used to treat refractory cases of obsessive compulsive disorder (OCD), normalizes patterns of activity and connectivity in the brains of these patients, reports a paper published online this week in Nature Neuroscience.
Martijn Figee and colleagues monitored brain activity of OCD patients and healthy controls during a functional magnetic resonance imaging experiment where participants worked on a reward anticipation task. OCD patients show reduced activity in a brain region called the nucleus accumbens, which is important for processing rewards, during reward anticipation compared to healthy controls, but the authors found that this difference was normalized if they administered DBS to OCD patients. Connectivity between the nucleus accumbens and frontal cortex was also elevated in OCD patients compared to controls, and here too normal levels were restored by DBS. Lastly, Figee and colleagues found that DBS also reversed abnormal patterns of activity provoked when patients looked at pictures that trigger their symptoms.
Although DBS is used in the treatment of OCD, it is unknown how it leads to decreases in compulsive behavior. This study provides insights into the alterations in brain activity induced by DBS that may underlie its therapeutic effects.