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Studies indicate that social status influences people's social perceptions. Less information is available about whether induced social status influences dyadic coordination during motor interactions. To explore this issue, we designed a study in which two confederates obtained high or low competence-based status by playing a game together with the participant, while the participant always occupied the middle position of the hierarchy. Following this status-inducing phase, participants were engaged in a joint grasping task with the high- and low-status confederates in different sessions while behavioural (i.e., interpersonal asynchrony and movement start time) indexes were measured. Participants' performance in the task (i.e., level of interpersonal asynchrony) when interacting with the low-status partner was modulated by their preference for him. The lower participants' preference for a low- relative to a high-status confederate, the worse participants' performance when interacting with the low-status confederate. Our results show that participants' performance during motor interactions changes according to the social status of the interaction partner.

The primary motor cortex (M1) is highly influenced by premotor/motor areas both within and across hemispheres. Dual site transcranial magnetic stimulation (dsTMS) has revealed interhemispheric interactions mainly at early latencies. Here, we used dsTMS to systematically investigate long-latency causal interactions between right-hemisphere motor areas and the left M1 (lM1). We stimulated lM1 using a suprathreshold test stimulus (TS) to elicit motor-evoked potentials (MEPs) in the right hand. Either a suprathreshold or a subthreshold conditioning stimulus (CS) was applied over the right M1 (rM1), the right ventral premotor cortex (rPMv), the right dorsal premotor cortex (rPMd) or the supplementary motor area (SMA) prior to the TS at various CS-TS inter-stimulus intervals (ISIs: 40-150 ms). The CS strongly affected lM1 excitability depending on ISI, CS site and intensity. Inhibitory effects were observed independently of CS intensity when conditioning PMv, rM1 and SMA at a 40-ms ISI, with larger effects after PMv conditioning. Inhibition was observed with suprathreshold PMv and rM1 conditioning at a 150-ms ISI, while site-specific, intensity-dependent facilitation was detected at an 80-ms ISI. Thus, long-latency interhemispheric interactions, likely reflecting indirect cortico-cortical/cortico-subcortical pathways, cannot be reduced to nonspecific activation across motor structures. Instead, they reflect intensity-dependent, connection- and time-specific mechanisms.

During social interactions people automatically apply stereotypes in order to rapidly categorize others. Racial differences are among the most powerful cues that drive these categorizations and modulate our emotional and cognitive reactivity to others. We investigated whether implicit racial bias may also shape hand kinematics during the execution of realistic joint actions with virtual in- and out-group partners. Caucasian participants were required to perform synchronous imitative or complementary reach-to-grasp movements with avatars that had different skin color (white and black) but showed identical action kinematics. Results demonstrate that stronger visuo-motor interference (indexed here as hand kinematics differences between complementary and imitative actions) emerged: i) when participants were required to predict the partner's action goal in order to on-line adapt their own movements accordingly; ii) during interactions with the in-group partner, indicating the partner's racial membership modulates interactive behaviors. Importantly, the in-group/out-group effect positively correlated with the implicit racial bias of each participant. Thus visuo-motor interference during joint action, likely reflecting predictive embodied simulation of the partner's movements, is affected by cultural inter-individual differences.

A wide network of interconnected areas was previously found in neuroimaging studies involving normal as well as pathological subjects; however literature seems to suffer from a lack of investigation in glucose metabolism behaviour under olfactory condition. Thus, the present work describe for the first time a pure olfactory related brain response of metabolism by using (18)F-fluorodeoxyglucose-Positron Emission Tomography/Computer Tomography in eleven resting subjects undergoing a neutral and a pure olfactory condition. By contrasting these experimental phases, it was possible to depict a re-organization pattern of default mode network structures in a relatively ecological environment. Moreover, by correlating such pattern with a battery of validated olfactory and neuropsychological tests, our work allowed in showing peculiar correlation data that could cluster the subjects sample in a certain range of normality. We believe the present study could integrate the current knowledge in olfactory research and could be a start-up for future contributions.

Although inherently linked, body form and body action may be represented in separate neural substrates. Using repetitive transcranial magnetic stimulation in healthy individuals, we show that interference with the extrastriate body area impairs the discrimination of bodily forms, and interference with the ventral premotor cortex impairs the discrimination of bodily actions. This double dissociation suggests that whereas extrastriate body area mainly processes actors' body identity, premotor cortex is crucial for visual discriminations of actions.