Bilateral Transcranial Direct Stimulation Over the Primary Motor Cortex Alters Motor Modularity of Multiple Muscles

Abstract

Transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) has been demonstrated to modulate the motor performance of both healthy individuals and patients with neuromuscular disorders. However, the effect of tDCS on motor control of multiple muscles, which is a prerequisite to change in motor performance, is currently unknown. Using dimensionality reduction analysis, we investigated whether bilateral tDCS over M1 modulates the coordinated activity of 12 muscles. Fifteen healthy men participated in this randomized, double-blind crossover study. Each participant received a 20-min sham and 2-mA stimulation bilaterally over M1 (anode on the right M1 and cathode on the left M1), with a minimum washout period of 4?days. Muscle activation and end-point kinematics were evaluated during a task where participants reached out to a marked target with non-dominant hand as fast as possible, before and immediately after tDCS application. We found decreased similarity in motor modularity and significant changes in muscle activation in a specific motor module, particularly when reaching out to a target placed within arm’s length and improved smoothness index of movement only following 2-mA stimulation. These findings indicate that clinicians and researchers need to consider the simultaneous effect of bilateral tDCS over M1 on multiple muscles when they establish tDCS protocol to change in motor performance of patients with neuromuscular deficits.     

Psychological and social functioning are associated with reports of perceived weight discrimination across eight years

This research uses the Health and Retirement Study to identify psychological and social factors that prospectively predict new reports of perceived weight discrimination among individuals who measure in the obese weight category. Participants (M_age = 66.89, SD = 8.33; 58% women) reported on their personality and social isolation, had a body mass index (BMI) ≥ 30, reported no perceived weight discrimination at baseline, and completed at least one assessment over the up to 8-year follow-up (N = 3,064). Eleven percent of participants reported new experiences of perceived weight discrimination. Higher Neuroticism and loneliness at baseline were associated with new reports; Conscientiousness was protective. This research adds to models of weight stigma by identifying psychological and social factors that contribute to reporting new instances of perceived weight discrimination.     

Enhancing social diffusion theory as a basis for prevention intervention: A conceptual and strategic framework

Social diffusion theory has recently been recognized as a promising approach for large-scale disease prevention and health promotion efforts. This paper describes how principles and tactics from social cognitive theory, operant psychology, social psychology, social marketing, and the overarching stages of change model can be used to further develop the conceptual and strategic (technological) bases of social diffusion theory. Within an integrative framework, we discuss in detail more effective ways to train peer mediators of behavior change as one example of how social diffusion theory can benefit from this conceptual and strategic reformulation. We then further illustrate the use of peer mediators of change in human immunodeficiency virus (HIV) and cancer prevention intervention studies with both interventions training peer mediators to diffuse information, norms, and risk reduction strategies. Although the results of these studies showed reductions in high-risk behaviors across population segments, more closely following the framework discussed in this article should further increase the behavior change potential of future interventions based on social diffusion theory.     

The intersectionality of race/ethnicity and socioeconomic status on social and emotional skills

The intersectionality of race/ethnicity and socioeconomic status (SES) in predicting social and emotional (SE) skills was examined for 81,950 6th–8th graders. At low levels of SES, White students tended to have the lower SE scores. However, as SES increased, they tended to have higher scores relative to minority groups. Across SES levels, Asian students showed higher Academic Discipline and Self-Regulation scores. The SES and SE skill relationship was less pronounced for underserved minority groups. This may be among the first reports where a measure of SE skills has documented different relationships with SES as a function of race/ethnicity. Possible explanations for these findings, as well as implications for designing culturally responsive programs that focus on SE skills, are discussed.     

Utilisation de l’engagement pour limiter la valorisation des fumeurs chez les adolescents

IntroductionSocial psychology research about commitment has demonstrated that it is possible to change one people's cognition and behavior.ObjectiveThe aim of the present article is to show that commitment can be used as a reduction strategy of smokers’ valorization and smoking normativity in order to reduce smoking.MethodStudents have been followed into a longitudinal study from end of elementary school to 8th grade class. They have been divided into different groups representing the smoking prevention's degree of commitment.ResultsRsults suggest that the sooner they are engaged in schooling, the better is the prevention. Commitment intervention made later in schooling has no influence on students smoking valorization.ConclusionResults will be discussed in terms of commitment theory by highlighting that an intervention using commitment is efficient only if the target is not already committed in an opposite behavior.     

Evaluating agents’ trustworthiness within virtual societies in case of no direct experience

A great deal of effort has been made to introduce trust models to assess trustworthiness within virtual societies. The great majority of them makes extensive use of direct experience as the main source of information, considering recommendation/reputation and inferential processes just later, as a secondary mechanism to refine trust assessment. In this kind of networks, unfortunately, direct experience might not always represent the best solution to assess trustworthiness. In fact, their highly dynamic structure promotes an increase of the average number of interconnections among agents. This in turn negatively affects the degree of knowledge the agents possess about each specific individual, i.e. direct experience. To date, however, it has not been said much about how to face these situations.It is fundamental to find an effective approach for trust assessment even in lack of direct experience, which is the central focus of this research. By the means of a multi-agent social simulation, we consider the situation in which an agent can just access indirect knowledge for trust assessment, namely recommendations of specific individuals or whole categories of individuals. Then, we compare the efficiency of these two approaches in order to identify when it is more convenient to rely on the first or on the second one. As expected, our results confirm that the dynamic nature of these networks strongly affects the role of categories. We modeled this feature introducing the “turnover” in the simulations, whereby the higher is the turnover the more convenient it is relying on categories. Besides this confirmatory result, our simulations highlight the higher degree of robustness of categories in the presence of unreliable recommenders. Such a result is even more significant if there is no available information about how reliable the recommenders are.The results we obtained are in accordance with the current literature and can be of important interest for the development of this sector.     

La déférence : une norme sociale complémentaire de l’internalité en contexte de promotion professionnelle ?

Regarding evaluation, numerous researches highlighted the social valuation of the internality. From the end of 1990s, the diversification of the studied situations came to put in perspective the impact of this norm, while revealing the existence of others social norms. The present research was designed to investigate the phenomenon of social valuation of the deference in situation of annual performance review. The social valuation of the power of others was examined by two studies: one led from paradigm of autopresentation with employees and other one, conducted under legislator paradigm with Human Resources specialists (students in their final year of Institutes Business Administration). If the results indicate, in a classic way, important normative effects of the internality, the valuation of the deferential explanations is globally so obvious. These results question about the contextual expression of a norm of deference: employees and RH experts give weight to the power of others. The results show a convergent use of the internality and the power of others.     

The relationship between peer servant leadership,social identity,and team cohesion in intercollegiate athletics

Servant leadership is characterized by a leader’s emphasis on serving their followers first. Within the sport context, servant leadership has been studied primarily in coaches and has been associated with positive athlete outcomes, such as increased athlete satisfaction, motivation, and performance. However, the impact of servant leadership from an athlete perspective (e.g., formal team captains) has been underexplored. As such, the purpose of the present study was to examine the relationships between peer servant leadership, cohesion, and social identity within intercollegiate athletes. Two hundred and eighty-eight Division I and Division III NCAA intercollegiate athletes participated in the present study (female n = 165; male n = 123; M_age = 19.41, SD_age = 1.09) and completed the Revised Servant Leadership Profile for Sport (RSLP-S; Hammermeister et al., 2008), Group Environment Questionnaire (GEQ; Carron et al., 1985; Eys et al., 2007), and Social Identity Questionnaire for Sport (SIQS; Bruner & Benson, 2018). Structural equation modeling was used to assess the relationships between peer servant leadership, cohesion, and social identity. Results revealed that peer servant leadership positively predicted cohesion, and this relationship was fully mediated by social identity. The current study supports the effectiveness of peer servant leadership in sport contexts and provides theoretical support for the social identity approach to leadership.