Examining frontotemporal connectivity and rTMS in healthy controls: implications for auditory hallucinations in schizophrenia.

Objective: Repetitive transcranial magnetic stimulation (rTMS) has been shown to have clinically beneficial effects in altering the perception of auditory hallucinations (AH) in patients with schizophrenia. However, the mode of action is not clear. Recent neuroimaging findings indicate that rTMS has the potential to induce not only local effects but also changes in remote, functionally connected brain regions. Frontotemporal dysconnectivity has been proposed as a mechanism leading to psychotic symptoms in schizophrenia. The current study examines functional connectivity between temporal and frontal brain regions after rTMS and the implications for AH in schizophrenia. Method: A connectivity analysis was conducted on the fMRI data of 11 healthy controls receiving rTMS, compared with 11 matched subjects receiving sham TMS, to the temporoparietal junction, before engaging in a task associated with robust frontotemporal activation. Results: Compared to the control group, the rTMS group showed an altered frontotemporal connectivity with stronger connectivity between the right temporoparietal cortex and the dorsolateral prefrontal cortex and the angular gyrus. Conclusion: This finding provides preliminary evidence for the hypothesis that normalizing the functional connectivity between the temporoparietal and frontal brain regions may underlie the therapeutic effect of rTMS on AH in schizophrenia. © 2012 American Psychological Association

Trust and social reciprocity in adolescence – a matter of perspective-taking

Changes in social behaviour from childhood to adulthood have been suggested to be driven by an increased sensitivity to others' perspectives. Yet, the link between perspective-taking and social processes, such as trust and reciprocity, has rarely been investigated during adolescence. Using two trust games with a cooperative and an unfair counterpart and an online perspective-taking task with 50 adolescents, we show that those with a higher perspective-taking tendency demonstrate greater trust towards others and higher levels of trust during cooperative interactions. Both low and high perspective-takers adapted their levels of trust in response to unfair behaviour. However, high perspective-takers reduced their trust more drastically and showed more malevolent and less benevolent tit-for-tat when they were treated unfairly by their counterpart. The findings suggest that a higher perspective-taking tendency in adolescence is associated with specific mechanisms of trust and reciprocity, as opposed to undifferentiated increases in positive social behaviour towards others

Alexithymia influences brain activation during emotion perception but not regulation

Alexithymia is a psychological construct that can be divided into a cognitive and affective dimension. The cognitive dimension is characterized by difficulties in identifying, verbalizing and analysing feelings. The affective dimension comprises reduced levels of emotional experience and imagination. Alexithymia is widely regarded to arise from an impairment of emotion regulation. This is the first functional magnetic resonance imaging (fMRI) study to critically evaluate this by investigating the neural correlates of emotion regulation as a function of alexithymia levels. The aim of the current study was to investigate the neural correlates underlying the two alexithymia dimensions during emotion perception and emotion regulation. Using fMRI, we scanned 51 healthy subjects while viewing, reappraising or suppressing negative emotional pictures. The results support the idea that cognitive alexithymia, but not affective alexithymia, is associated with lower activation in emotional attention and recognition networks during emotion perception. However, in contrast with several theories, no alexithymia-related differences were found during emotion regulation (neither reappraisal nor suppression). These findings suggest that alexithymia may result from an early emotion processing deficit rather than compromised frontal circuits subserving higher-order emotion regulation processes