A Time-Varying Measure of Dyadic Synchrony for Three-Dimensional Motion

We propose a novel approach to the analysis of synchronized three-dimensional motion in dyads. Motion recorded at high time resolution, as with a gaming device, is preprocessed in each of the three spatial dimensions by spline smoothing. Synchrony is then defined, at each time point, as the cosine between the two individuals’ estimated velocity vectors. The approach is extended to allow a time lag, allowing for the analysis of leader-follower dynamics. Mean square cosine over the time range is proposed as a scalar summary of dyadic synchrony, and this measure is found to be positively associated with cognitive empathy.     

第三方惩罚的神经机制：来自经颅直流电刺激的证据

第三方惩罚既是社会规范在群体得以维系的基石, 也是个体维护社会规范的体现。当前关注社会规范的神经研究大多基于第二方惩罚的独裁者或最后通牒实验框架, 缺乏对第三方维护社会规范过程中相关脑区活动的探索, 对这一过程的内在神经机制也不清楚。本文基于第三方惩罚的独裁者博弈框架, 对右侧背外侧前额叶区域(DLPFC)进行不同极性的经颅直流电刺激(tDCS), 同时依据第三方是否需要为其惩罚付出成本设计了零成本和有成本两个实验任务。结果发现, 第三方在零成本任务的情绪反应和惩罚显著受到tDCS设置的影响, 且阴极刺激显著提升了第三方的惩罚值, 这表明情绪机制对第三方惩罚有着重要影响。另外, 第三方在零成本和有成本任务中的惩罚差异在不同tDCS设置之间也存在显著差异, 这与第三方惩罚还受到自利机制影响的观点相符。本文率先为右侧DLPFC活动影响第三方惩罚提供了神经层面的证据, 且支持了第三方对社会规范的遵从与其负性情绪反应和自利加工密切相关的机制解释。     

Rhythmic priming across effector systems: A randomized controlled trial with Parkinson’s disease patients

This study investigated the immediate effects of auditory-motor entrainment across effector systems by examining whether Rhythmic Auditory Stimulation training of arm or finger movements would modulate gait speed. Forty-one participants with idiopathic Parkinson’s Disease were randomly assigned to 3 groups. Participants in the finger-tapping group tapped in synchrony with a metronome set to 20% faster pace than the pre-training walking cadence, whereas participants in the other group were asked to swing both arms in an alternating motion in synchrony with the metronome. Participants in the control condition did not receive training. To assess gait parameters pre- and post-training, participants walked on a 14-meter flat walkway at his/her preferred walking cadence with no auditory cueing. Results indicated that there was a significant increase in gait velocity after the finger tapping training (p < .005), whereas no differences were observed in the arm swing (p = .802) and in the control conditions (p = .525). Similarly, there were significant changes in gait cadence post-training in the finger tapping group (p < .005), but not after arm swing training (p = .879) or control (p = .759). There were no significant changes in stride length post-training in none of the groups. These findings suggest that auditory-motor entrainment in one effector system may prime a second effector system. Interestingly, however, the priming effect on gait was only observed in the finger tapping condition and not with synchronized arm swing movements. These findings have significant implications for motor rehabilitation and open new avenues for further investigation of the mechanisms underlying cross-effector coupling.     

Noninvasive brain stimulation over M1 and DLPFC cortex enhances the learning of bimanual isometric force control

Motor learning plays an important role in upper-limb function and the recovery of lost functionality. This study aimed to investigate the relative impact of transcranial direct current stimulation (tDCS) on learning in relation to the left primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC) during bimanual isometric force-control tasks performed with both hands under different task constraints. In a single-blind cross-over design, 20 right-handed participants were randomly assigned to either the M1 group (n = 10; mean age, 22.90 ± 1.66 years, mean ± standard deviation) or the DLPFC group (n = 10; mean age, 23.20 ± 1.54 years). Each participant received 30 min of tDCS (anodal or sham, applied randomly in two experiments) while performing the bimanual force control tasks. Anodal tDCS of the M1 improved the accuracy of maintenance and rhythmic alteration of force tasks, while anodal tDCS of the DLPFC improved only the maintenance of the force control tasks compared with sham tDCS. Hence, tDCS over the left M1 and DLPFC has a beneficial effect on the learning of bimanual force control.     

Testing the role of cognitive inhibition in physical endurance using high-definition transcranial direct current stimulation over the prefrontal cortex

The aim of this study was to clarify the role of the prefrontal cortex (PFC) in physical effort regulation. We hypothesized that the PFC would be progressively involved in physical endurance through the engagement of cognitive inhibition, which would be necessary to maintain effort by inhibiting fatigue-related cues. This hypothesis was examined using a double-blind, sham-controlled, within-subjects study (N = 20) using high-definition (HD) transcranial direct current stimulation (tDCS) over the right dorsolateral prefrontal cortex (dlPFC). Participants had to maintain a knee extensor contraction at 30% of their maximal force while simultaneously performing an Eriksen flanker task to evaluate their inhibition performance during the task. Anodal stimulation of the dlPFC influenced response to the cognitive task during exercise, as seen by slower response times and better accuracy. However, it did not lead to any measureable improvement in cognitive inhibition and did not influence endurance time. There was no correlation between cognitive inhibition and the maintenance of physical effort. This result does not indicate a relationship between cognitive inhibition and endurance performance. The contribution of the PFC in physical endurance could be explained through its involvement on decisional processes.     

High test-retest reliability of a neural index of rapid automatic discrimination of unfamiliar individual faces

An important aspect of human individual face recognition is the ability to discriminate unfamiliar individual. Since many general processes contribute to explicit behavioural performance in individual face discrimination tasks, isolating a measure of unfamiliar individual face discrimination ability in humans is challenging. In recent years, a fast periodic visual stimulation approach (FPVS) has provided objective (frequency-locked) implicit electrophysiological indices of individual face discrimination that are highly sensitive at the individual level within a few minutes of testing. Here we evaluate the test-retest reliability of this response across scalp electroencephalographic (EEG) recording sessions separated by more than two months, in the same 30 individuals. We found no test-retest difference overall across sessions in terms of amplitude and spatial distribution of the EEG individual face discrimination response. Moreover, with only 4 stimulation sequences corresponding to 4 min of recordings per session, the individual face discrimination response was highly reliable in terms of amplitude, spatial distribution, and shape. Together with previous observations, these results strengthen the diagnostic value of FPVS-EEG as an objective and rapid flag for specific difficulties at individual face recognition in the human population.     

Joint roles of parenting and nutritional status for child development: Evidence from rural Cambodia

Substantial work has demonstrated that early nutrition and home environments, including the degree to which children receive cognitive stimulation and emotional support from parents, play a profound role in influencing early childhood development. Yet, less work has documented the joint influences of parenting and nutritional status on child development among children in the preschool years living in low‐income countries. Using panel data from 2016 to 2017 on the parenting, nutritional status, and early developmental outcomes (executive function, language, early numeracy, and socioemotional problems) of 6,508 Cambodian children ages 3–5 years, our findings demonstrate that inequities in early development associated with family wealth are evident at age 3 and increase among children ages 4 and 5 years. Using hierarchical regression analysis, a significant share of these inequalities is explained by differences in parenting and early nutritional status, measured by stunting. Better‐educated parents engage in more stimulating and supportive parenting practices. However, the positive association between parenting and language and early numeracy outcomes is 35–54% stronger for non‐stunted children, and parental activities explain only about 8–14% of the cognitive gap between the lowest and highest wealth quintiles. The results highlight the need for additional research outlining interactions between environmental factors that link family wealth and child development.     

Comparing positive and negative reinforcement: A fantasy experiment

We propose quantitative experimental approaches to the question of whether positive and negative reinforcement are functionally different, and discuss scientific and ethical concerns that would arise if these approaches were pursued.     

Neural correlates of subliminally presented visual sexual stimuli

In the context of forensic psychiatry, it is crucial that diagnoses of deviant sexual interests are resistant to manipulation. In a first attempt to promote the development of such tools, the current fMRI study focusses on the examination of hemodynamic responses to preferred, in contrast to non-preferred, sexual stimuli with and without explicit sexual features in 24 healthy heterosexual subjects. The subliminal stimulus presentation of sexual stimuli could be a new approach to reduce vulnerability to manipulation. Meaningful images and scrambled images were applied as masks. Recognition performance was low, but interestingly, sexual preference and explicitness modulated stimulus visibility, suggesting interactions between networks of sexual arousal and consciousness. With scrambled masks, higher activations for sexually preferred images and for explicit images were found in areas associated with sexual arousal (Stoleru, Fonteille, Cornelis, Joyal, & Moulier, 2012). We conclude that masked sexual stimuli can evoke activations in areas associated with supraliminal induced sexual arousal.     

经颅直流电刺激提高记忆功能

经颅直流电刺激是最近复兴的非侵入性无创脑刺激方法, 具有轻便、廉价、较为安全的特点。经颅直流电刺激能产生一系列生理变化, 相比传统脑成像方法具有优势, 在工作记忆、陈述性记忆、程序性记忆上已有应用, 可与传统认知训练相结合。经颅直流电刺激虽然不能进行精确定位, 但是能够基于脑区影响个体认知加工过程。经颅直流电刺激在临床上可以作为治疗手段, 对健康人可以作为神经训练的方法, 在心理学领域具有良好的研究前景。