and norepinephrine activity, which improves executive and attentional functioning and emotion regulation [173], in addition to influencing reward mechanisms as reported above. However, there are some case reports that methylphenidate can worsen OCD symptoms [174] and for some patients antipsychotic medications that reduce dopamine levels are effective [175] (Table 3). These findings are in line with other research indicating that optimal dopamine levels for executive functions follow an inverted U-shaped curve and depend on the individual’s baseline levels [176]. Non-invasive neuromodulatory approaches (rTMS, tDCS) stimulating dorsal cognitive regions including the dlPFC and pre-SMA show efficacy in reducing OCD symptoms [62, 177–179] even in treatment-resistant cases [178–179]. It should be noted, however, that the pre-SMA target is likely to affect activity in several circuits (sensorimotor, ventral cognitive) and not the dorsal cognitive circuit alone.
