Can we modulate obsessive-compulsive networks with neuromodulation?

Neuromodulation techniques represent a network pathway-oriented treatment that can be considered as a promising tool in the achievement of "precision medicine" and a research domain criteria -based approach to treat several psychiatric disorders, including obsessive-compulsive disorder (OCD). Both repetitive transcranial magnetic stimulation (rTMS) targeting the pre-supplementary motor area (pre-SMA), deep TMS (dTMS) targeting the orbitofrontal cortex (OFC) and deep brain stimulation (DBS) targeting the nucleus accumbens (Nacc) and ventral capsule/ventral striatum (VC/VS) seem to be effective in improving obsessive-compulsive symptoms and to restore dysfunctional prefrontal-striatal and pre-motor circuitries. Transcranial direct current stimulation (tDCS) effects on obsessive-compulsive symptoms have been less investigated, and the bulk of the available data is from case reports. Nevertheless, promising results are shown for cathodal stimulation of the OFC, while stimulation of the dorsolateral prefrontal cortex (DLPFC) failed to improve symptomatology. The aim of this review is to discuss the effects of both invasive and non-invasive neuromodulation techniques in OCD, focusing on its core dysfunctional networks such as prefrontal-striatal and SMA networks.