The impact of mindfulness meditation on social and moral behavior: Does mindfulness enhance other-oriented motivation or decrease monetary reward salience?

This perspective article provides an overview of the impact of mindfulness meditation (MM) on social and moral behavior. In mindfulness research, prosocial behavior has been operationalized as helping behavior, altruistic redistribution of funds, reparative behavior, or monetary donation. Studies concerning moral behavior are still scarce. Despite inconsistent evidence, several studies found a beneficial effect of mindfulness on prosocial outcomes (i.e., a higher propensity to spend or give away money for the sake of other individuals). However, since the employed tasks were reward-based, participants' decisions also directly affected their own payoff by reducing it. Crucially, MM also affects self-control circuitry and reduces reward-seeking behaviors and reward salience by making rewards less tempting. We have discussed evidence suggesting how challenging it may be to dissociate the specific weight of enhanced other-oriented motivation from one of the decreased monetary reward salience in explaining meditators' behavior. Future higher-quality studies are needed to address this open issue.

Differential Influence of the Dorsal Premotor and Primary Somatosensory Cortex on Corticospinal Excitability during Kinesthetic and Visual Motor Imagery: A Low-Frequency Repetitive Transcranial Magnetic Stimulation Study.

Consistent evidence suggests that motor imagery involves the activation of several sensorimotor areas also involved during action execution, including the dorsal premotor cortex (dPMC) and the primary somatosensory cortex (S1). However, it is still unclear whether their involvement is specific for either kinesthetic or visual imagery or whether they contribute to motor activation for both modalities. Although sensorial experience during motor imagery is often multimodal, identifying the modality exerting greater facilitation of the motor system may allow optimizing the functional outcomes of rehabilitation interventions. In a sample of healthy adults, we combined 1 Hz repetitive transcranial magnetic stimulation (rTMS) to suppress neural activity of the dPMC, S1, and primary motor cortex (M1) with single-pulse TMS over M1 for measuring cortico-spinal excitability (CSE) during kinesthetic and visual motor imagery of finger movements as compared to static imagery conditions. We found that rTMS over both dPMC and S1, but not over M1, modulates the muscle-specific facilitation of CSE during kinesthetic but not during visual motor imagery. Furthermore, dPMC rTMS suppressed the facilitation of CSE, whereas S1 rTMS boosted it. The results highlight the differential pattern of cortico-cortical connectivity within the sensorimotor system during the mental simulation of the kinesthetic and visual consequences of actions.

Thoughts of death modulate psychophysical and cortical responses to threatening stimuli.

Existential social psychology studies show that awareness of one's eventual death profoundly influences human cognition and behaviour by inducing defensive reactions against end-of-life related anxiety. Much less is known about the impact of reminders of mortality on brain activity. Therefore we explored whether reminders of mortality influence subjective ratings of intensity and threat of auditory and painful thermal stimuli and the associated electroencephalographic activity. Moreover, we explored whether personality and demographics modulate psychophysical and neural changes related to mortality salience (MS). Following MS induction, a specific increase in ratings of intensity and threat was found for both nociceptive and auditory stimuli. While MS did not have any specific effect on nociceptive and auditory evoked potentials, larger amplitude of theta oscillatory activity related to thermal nociceptive activity was found after thoughts of death were induced. MS thus exerted a top-down modulation on theta electroencephalographic oscillatory amplitude, specifically for brain activity triggered by painful thermal stimuli. This effect was higher in participants reporting higher threat perception, suggesting that inducing a death-related mind-set may have an influence on body-defence related somatosensory representations.

Listening to your heart and feeling yourself: effects of exposure to interoceptive signals during the ultimatum game.

The ultimatum game (UG) is commonly used to study the tension between financial self-interest and social equity motives. Here, we investigated whether experimental exposure to interoceptive signals influences participants' behavior in the UG. Participants were presented with various bodily sounds--i.e., their own heart, another person's heart, or the sound of footsteps--while acting both in the role of responder and proposer. We found that listening to one's own heart sound, compared to the other bodily sounds: (1) increased subjective feelings of unfairness, but not rejection behavior, in response to unfair offers and (2) increased the unfair offers while playing in the proposer role. These findings suggest that heightened feedback of one's own visceral processes may increase a self-centered perspective and drive socioeconomic exchanges accordingly. In addition, this study introduces a valuable procedure to manipulate online the access to interoceptive signals and for exploring the interplay between viscero-sensory information and cognition.

Kinematics fingerprints of leader and follower role-taking during cooperative joint actions.

Performing online complementary motor adjustments is quintessential to joint actions since it allows interacting people to coordinate efficiently and achieve a common goal. We sought to determine whether, during dyadic interactions, signaling strategies and simulative processes are differentially implemented on the basis of the interactional role played by each partner. To this aim, we recorded the kinematics of the right hand of pairs of individuals who were asked to grasp as synchronously as possible a bottle-shaped object according to an imitative or complementary action schedule. Task requirements implied an asymmetric role assignment so that participants performed the task acting either as (1) Leader (i.e., receiving auditory information regarding the goal of the task with indications about where to grasp the object) or (2) Follower (i.e., receiving instructions to coordinate their movements with their partner's by performing imitative or complementary actions). Results showed that, when acting as Leader, participants used signaling strategies to enhance the predictability of their movements. In particular, they selectively emphasized kinematic parameters and reduced movement variability to provide the partner with implicit cues regarding the action to be jointly performed. Thus, Leaders make their movements more "communicative" even when not explicitly instructed to do so. Moreover, only when acting in the role of Follower did participants tend to imitate the Leader, even in complementary actions where imitation is detrimental to joint performance. Our results show that mimicking and signaling are implemented in joint actions according to the interactional role of the agent, which in turn is reflected in the kinematics of each partner.

The sound of actions in apraxia.

Studies in nonhuman and human primates have demonstrated that sound-producing actions are mapped on the same mirror circuits that are activated during the visual recognition and execution of actions [1-12]. However, no causative link between the auditory recognition and execution of actions has been provided thus far. Here, we sought to determine whether patients with apraxia, who are by definition impaired in performing specific gestures, are also impaired in recognizing sounds specifically linked to human actions. Twenty-eight left-hemisphere-damaged patients with or without limb and/or buccofacial apraxia and seven right-hemisphere-damaged patients with no apraxia were asked to match sounds evoking human-related actions or nonhuman action sounds with specific visual pictures. Hand and mouth action-related sound recognition were specifically impaired in limb and buccofacial apraxia patients, respectively. Lesional mapping revealed that the left frontoparietal cortex is crucial for recognizing the sound of limb movements. By contrast, the left inferior frontal gyrus and adjacent insular cortex are causatively associated with recognition of buccofacial-related action sounds. These behavioral and neural double dissociations indicate that a left-lateralized multimodal mirror network is actively involved in the body-part-specific motor mapping of limb and mouth action-related sounds, as well as in the execution of the very same actions.