No abstract

The ability to infer value from the reactions of other people is a common and essential ability with a poorly understood neurobiology. Commonly, social learning matches one's values and behavior to what is perceived as normal for one's social group. This is known as conformity. Conformity of value correlates with neural activity shared by cognitions that depend on optimum catecholamine levels, but catecholamine involvement in conformity has not been tested empirically. Methylphenidate (MPH) is an indirect dopamine and noradrenalin agonist, commonly used for the treatment of attention-deficit hyperactivity disorder for which it reduces undesirable behavior as evaluated by peers and authority figures, indicative of increased conformity. We hypothesized that MPH might increase conformity of value. In all, 38 healthy adult females received either a single oral 20 mg dose of MPH or placebo (PL). Each subject rated 153 faces for trustworthiness followed immediately by the face's mean rating from a group of peers. After 30 min and a 2-back continuousperformance working-memory task, subjects were unexpectedly asked to rate all the faces again. Both the groups tended to change their ratings towards the social norm. The MPH group exhibited twice the conformity effect of the PL group following moderate social conflict, but this did not occur following large conflicts. This suggests that MPH might enhance signals that would otherwise be too weak to evoke conformity. MPH did not affect 2-back performance. We provide a new working hypothesis of a neurocognitive mechanism by which MPH reduces socially disruptive behavior and provides novel evidence of catecholamine mediation of social learning.

This is evidence that serotonin systems can mediate explicit assessment and social learning of the trustworthiness of others.

No abstract

Highlights Parkinson’s disease (PD) affects motor system and cognitive skills such as language. We used machine learning to study language network connectivity in early-stage PD. Connectivity was probed by classifying MEG responses to different spoken words. PD vs controls were successfully classified using verbs and incorrectly inflected nouns. Early-stage PD exhibits altered language network connectivity despite normal cognition.