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Mentalizing is a fundamental process underpinning human social interaction. Claims of the existence of 'implicit mentalizing' represent a fundamental shift in our understanding of this important skill, suggesting that preverbal infants and even animals may be capable of mentalizing. One of the most influential tasks supporting such claims in adults is the dot perspective-taking task, but demonstrations of similar performance on this task for mentalistic and non-mentalistic stimuli have led to the suggestion that this task in fact measures domain-general processes, rather than implicit mentalizing. A mentalizing explanation was supported by fMRI data claiming to show greater activation of brain areas involved in mentalizing, including right temporoparietal junction (rTPJ), when participants made self-perspective judgements in a mentalistic, but not in a non-mentalistic condition, an interpretation subsequently challenged. Here we provide the first causal test of the mentalizing claim using disruptive transcranial magnetic stimulation of rTPJ during self-perspective judgements. We found no evidence for a distinction between mentalistic and non-mentalistic stimuli: stimulation of rTPJ impaired performance on all self-perspective trials, regardless of the mentalistic/non-mentalistic nature of the stimulus. Our data support a domain-general attentional interpretation of performance on the dot perspective-taking task, a role which is subserved by the rTPJ., (Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.)

Although neuroimaging studies have consistently identified the temporoparietal junction (TPJ) as a key brain region involved in social cognition, the literature is far from consistent with respect to lateralization of function. For example, during theory-of-mind tasks bilateral TPJ activation is found in some studies but only right hemisphere activation in others. Visual perspective-taking and imitation inhibition, which have been argued to recruit the same socio-cognitive processes as theory of mind, are associated with unilateral activation of either left TPJ (perspective taking) or right TPJ (imitation inhibition). The present study investigated the functional lateralization of TPJ involvement in the above three socio-cognitive abilities using transcranial direct current stimulation. Three groups of healthy adults received anodal stimulation over right TPJ, left TPJ or the occipital cortex prior to performing three tasks (imitation inhibition, visual perspective-taking and theory of mind). In contrast to the extant neuroimaging literature, our results suggest bilateral TPJ involvement in imitation inhibition and visual perspective-taking, while no effect of anodal stimulation was observed on theory of mind. The discrepancy between these findings and those obtained using neuroimaging highlight the efficacy of neurostimulation as a complementary methodological tool in cognitive neuroscience., (© 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

The control of neurological networks supporting social cognition is crucially important for social interaction. In particular, the control of imitation is directly linked to interaction quality, with impairments associated with disorders characterized by social difficulties. Previous work suggests inferior frontal cortex (IFC) and the temporoparietal junction (TPJ) are involved in controlling imitation, but the functional roles of these areas remain unclear. Here, transcranial direct current stimulation (tDCS) was used to enhance cortical excitability at IFC and the TPJ prior to the completion of three tasks: (i) a naturalistic social interaction during which increased imitation is known to improve rapport, (ii) a choice reaction time task in which imitation needs to be inhibited for successful performance and (iii) a non-imitative control task. Relative to sham stimulation, stimulating IFC improved the context-dependent control of imitation-participants imitated more during the social interaction and less during the imitation inhibition task. In contrast, stimulating the TPJ reduced imitation in the inhibition task without affecting imitation during social interaction. Neither stimulation site affected the non-imitative control task. These data support a model in which IFC modulates imitation directly according to task demands, whereas TPJ controls task-appropriate shifts in attention toward representation of the self or the other, indirectly impacting upon imitation., (© The Author (2014). Published by Oxford University Press.)

The temporoparietal junction (TPJ) is a key node within the "social brain". Several studies suggest that the TPJ controls representations of the self or another individual across a variety of low-level (agency discrimination, visual perspective taking, control of imitation) and high-level (mentalizing, empathy) sociocognitive processes. We explored whether sociocognitive abilities relying on on-line control of self and other representations could be modulated with transcranial direct current stimulation (tDCS) of TPJ. Participants received excitatory (anodal), inhibitory (cathodal), or sham stimulation before completing three sociocognitive tasks. Anodal stimulation improved the on-line control of self-other representations elicited by the imitation and perspective-taking tasks while not affecting attribution of mental states during a self-referential task devoid of such a requirement. Our findings demonstrate the efficacy of tDCS to improve social cognition and highlight the potential for tDCS to be used as a tool to aid self-other processing in clinical populations., (Copyright © 2012 Elsevier Ltd. All rights reserved.)