Background: Repetitive transcranial magnetic stimulation (rTMS) has recently demonstrated significant potential in treating obsessive-compulsive disorder (OCD). However, its effectiveness depends on various parameters, including stimulation parameters, OCD subtypes and electrical fields (EFs) induced by rTMS in targeted brain regions that are less studied. Methods: Using the PRISMA approach, we examined 27 randomized control trials (RCTs) conducted from 1985 to 2024 using rTMS for the treatment of OCD and conducted several meta-analyses to investigate the role of rTMS parameters, including the EFs induced by each rTMS protocol, and OCD subtypes on treatment efficacy. Results: A significant, medium effect size was found, favoring active rTMS (g_PPC = 0.59, p < 0.0001), which was larger for the obsession subscale. Both supplementary motor area (SMA) rTMS (g_PPC = 0.82, p = 0.048) and bilateral dorsolateral prefrontal cortex (DLPFC) rTMS (gPPC = 1.14, p = 0.04) demonstrated large effect sizes, while the right DLPFC showed a significant moderate effect size for reducing OCD severity (g_PPC = 0.63, p = 0.012). These protocols induced the largest EFs in dorsal cognitive, ventral cognitive and sensorimotor circuits. rTMS protocols targeting DLPFC produced the strongest electrical fields in cognitive circuits, while pre-supplementary motor area (pre-SMA) and orbitofrontal cortex (OFC) rTMS protocols induced larger fields in regions linked to emotional and affective processing in addition to cognitive circuits. The pre-SMA rTMS modulated more circuits involved in OCD pathophysiology—sensorimotor, cognitive, affective, and frontolimbic—with larger electrical fields than the other protocols. Conclusions: While rTMS shows moderate overall clinical efficacy, protocols targeting ventral and dorsal cognitive and sensorimotor circuits demonstrate the highest potential. The pre-SMA rTMS appears to induce electrical fields in more circuits relevant to OCD pathophysiology.

Background: Theory of mind (ToM) or mentalizing, is the ability to attribute mental states to oneself and others and is altered in individuals with autism spectrum disorder (ASD). Recent evidence suggest that implicit, rather than explicit ToM is impaired in individuals with ASD. The right temporoparietal junction (rTPJ), which plays a crucial role in ToM, has altered activity in ASD and can be targeted by noninvasive brain stimulation. Methods: In a randomized double-blind placebo-controlled study, we investigated for the first time the effects of theta-burst stimulation of the rTPJ on implicit ToM and egocentric bias in seventeen adolescents with ASD. Participants (mean age = 13.84±3.32) were randomly assigned to three sessions each of continuous theta-burst stimulation (cTBS), intermittent theta-burst stimulation (iTBS), and sham stimulation. Stimulation intensity was set to 80% of the active motor threshold during cTBS and iTBS, with the coil centered on the rTPJ (CP6). Immediately after each stimulation, cognitive correlates of ToM, including implicit mentalizing and egocentric bias, were evaluated using the computerized Buzz-lightyear task. Results: Our results show that both cTBS and iTBS significantly improved implicit ToM in participants as compared to sham stimulation, with cTBS being more effective than iTBS. No effect of stimulation was, however, found on the egocentric bias index. Conclusions: These findings demonstrate a causal link between the rTPJ activation and implicit mentalizing in ASD, suggesting that theta-burst stimulation of this region can be used to enhance ToM in ASD. Targeting the rTPJ may improve implicit mentalizing in ASD and other disorders with impaired ToM.

Time and space are two intertwined contexts that frame our cognition of the world and have shared mechanisms. A well-known theory on this case is ‘A Theory of Magnitude (ATOM)’ which states that the perception of these two domains shares common mechanisms. However, evidence regarding shared computations of time and space is intermixed. To investigate this issue, we asked human subjects to reproduce time and distance intervals with saccadic eye movements in similarly designed tasks. We applied an observer model to both modalities and found underlying differences the processing of time and space. While time and space computations are both probabilistic, adding prior to space perception minimally improved model performance, as opposed to time perception which was consistently better explained by Bayesian computations. We also showed that while both measurement and motor variability were smaller in distance than time reproduction, only the motor variability was correlated between them, as both tasks used saccadic eye movements for response. Our results suggest that time and space perception abide by the same algorithm but have different computational properties.