The effects of sport dance on brain connectivity and body intelligence

Dancing is characterised by physical movement in accordance with rhythm perception. Twelve sport dancers and 12 age- and sex-matched young adults who had no dance experience (control group) were recruited. Body intelligence and brain activity were assessed in both groups using the Body Intelligence Scale (BIS) and resting state functional magnetic resonance imaging. BIS scores of dancers were higher than those of control subjects. The dancer group showed increased functional connectivity from the precentral gyrus to the right cingulate gyrus, right occipital fusiform gyrus, right inferior frontal gyrus, right medial frontal gyrus, left inferior frontal gyrus, right parietal postcentral gyrus, and right frontal lobe compared with control subjects. Sport dancers had increased body intelligence sensitivity compared with matched controls. In addition, the characteristics of dance, including physical movement in accordance with rhythm perception, might be associated with increased brain activity in the somatosensory and rhythm perception networks.     

运动技能水平与躯体感觉输入对运动表象的影响

运动表象质量与运动技能水平有关,运动表象质量随着运动技能水平的提高而上升。器械使用可使人脑产生可塑性改变,使用者会将器械纳入身体图式。然而,两者影响运动表象的神经心理机制还不清楚。本研究采用功能性磁共振成像探析篮球运动员与新手在不同持球条件下表象投篮时脑功能活动的差异。结果表明运动员表象质量较好,镜像神经系统激活高于新手;持球条件下运动员表象质量显著高于不持球条件下,镜像神经系统激活程度显著低于不持球条件下。研究说明持器械可以显著提高运动员的表象质量,器械使用带来镜像神经系统的可塑性变化。     

Dispositional aspects of body focus and idiopathic environmental intolerance attributed to electromagnetic fields (IEI‐EMF)

Body focus is often considered an undesirable characteristic from medical point of view as it amplifies symptoms and leads to higher levels of health anxiety. However, it is connected to mindfulness, well‐being and the sense of self in psychotherapy. The current study aimed to investigate the contribution of various body focus related constructs to acute and chronic generation and maintenance of medically unexplained symptoms (MUS). Thirty‐six individuals with idiopathic environmental intolerance to electromagnetic fields (IEI‐EMF) and 36 controls were asked to complete questionnaires assessing negative affect, worries about harmful effects of EMFs, health anxiety (HA), body awareness, and somatosensory amplification (SSA), and to report experienced symptoms evoked by a sham magnetic field. Body awareness, HA, SSA, and EMF‐related worries showed good discriminative power between individuals with IEI‐EMF and controls. Considering all variables together, SSA was the best predictor of IEI‐EMF. In the believed presence of a MF, people with IEI‐EMF showed higher levels of anxiety and reported more symptoms than controls. In the IEI‐EMF group, actual symptom reports were predicted by HA and state anxiety, while a reverse relationship between symptom reports and HA was found in the control group. Our findings show that SSA is a particularly important contributor to IEI‐EMF, probably because it is the most comprehensive factor in its aetiology. IEI‐EMF is associated with both a fear‐related monitoring of bodily symptoms and a non‐evaluative body focus. The identification of dispositional body focus may be relevant for the management of MUS.     

Difference in Cortical Relay Time Between Intrinsic Muscles of Dominant and Nondominant Hands

The authors aimed to calculate and compare cortical relay time (CRT) between intrinsic hand muscles and between homonymous muscles of dominant and nondominant hands. The participants comprised 22 healthy volunteers. The CRT for long-latency reflexes (LLRs) was calculated by subtracting the peak latency of somatosensory evoked potentials of component N20 and the onset latency of motor evoked potentials from the onset latency of LLRs. CRT was significantly shorter for the first dorsal interosseous muscle than for the abductor pollicis brevis muscle, regardless of hand dominance. CRT for the abductor pollicis brevis muscle was significantly shorter in the dominant hand than in the nondominant hand. Evaluation of CRT for intrinsic muscles might be beneficial in the understanding of individuated finger functions.     

Cultural influences in somatosensory amplification and their association with negative affective states

Previous research has indicated that, reflecting East Asians’ holistic attentional style, they are likely to emphasize more somatic symptoms and perceive their internal visceral states less accurately as compared with Westerners. Based on these findings, comparing representative samples of Americans and Japanese participants, this research examined whether somatosensory amplification would vary across cultures. Moreover, by controlling confounding factors, including neuroticism and chronic disorders, the possibility that the association between somatosensory amplification and negative affective states differs across cultures also was tested. The results showed that Japanese exhibit higher somatosensory amplification than do Americans. In both cultures, as neuroticism and the number of chronic disorders increased, negative affective states also increased, leading to higher somatosensory amplification. Whereas negative affective states completely mediated the paths of neuroticism and chronic disorders to somatosensory amplification in the United States, such mediation was partial in Japan. Moreover, the association between somatosensory amplification and negative affective states was weaker in Japanese than in Americans.     

Position Sense Dysfunction Affects Proximal and Distal Arm Joints in Children with Developmental Coordination Disorder

It is unclear, whether proprioceptive dysfunction in developmental coordination disorder (DCD) is localized affecting only specific joints or whether it is generalized affecting proximal and distal joints. Thus, this study assessed position sense acuity at the elbow and wrist in twenty children with DCD (age: 9–11 yrs.) using a joint position matching paradigm. Position sense bias (systematic error) at either joint was not significantly higher in DCD children when compared to typically developing children (TD). However, DCD children exhibited significantly lower position sense precision (random error) than TD children at both elbow and wrist. That is, response reliability to proprioceptive stimuli is altered in DCD. Our findings are consistent with a view that proprioceptive dysfunction in DCD is generalized in nature.     

The Effect of Paired Muscle Stimulation on Preparation for Movement

Paired muscle stimulation is used clinically to facilitate the performance of motor tasks for individuals with motor dysfunction. However, the optimal temporal relationship between stimuli for enhancing movement remains unknown. We hypothesized that synchronous, muscle stimulation would increase the extent to which stimulated muscles are concurrently prepared for movement. We validated a measure of muscle-specific changes in corticomotor excitability prior to movement. We used this measure to examine the preparation of the first dorsal interosseous (FDI), abductor digiti minimi (ADM), abductor pollicis brevis (APB) muscles prior to voluntary muscle contractions before and after paired muscle stimulation at four interstimulus intervals (0, 5, 10, and 75 ms). Paired muscle stimulation increased premovement excitability in the stimulated FDI, but not in the ADM muscle. Interstimulus interval was not a significant factor in determining efficacy of the protocol. Paired stimulation, therefore, did not result in a functional association being formed between the stimulated muscles. Somatosensory potentials evoked by the muscle stimuli were small compared to those commonly elicited by stimulation of peripheral nerves, suggesting that the lack of functional association formation between muscles may be due to the small magnitude of afferent volleys from the stimulated muscles, particularly the ADM, reaching the cortex.     

疼痛共情的神经机制

疼痛是一种多维度的体验。情感成分和感觉成分是疼痛体验的主要成分,二者有着不同的神经机制。疼痛共情是痛觉"共鸣"的情绪反应,其神经机制的研究也围绕疼痛的情感成分和感觉成分展开。疼痛共情的情感成分的相关脑区主要有前扣带皮层和脑岛等脑区,与自身疼痛时相比,它们的激活位点及所处的神经网络存在差异;疼痛共情的感觉成分主要与初级感觉皮层以及一些其它的躯体感觉皮层有关,对它们的激活情况的研究受技术手段和实验范式的影响较大。未来的研究应从技术手段、分析方法及实验操作上予以关注。     

Hand Grip and Load Force Coordination of the Ipsilesional Hand of Chronic Stroke Individuals

Object manipulation depends on a refined control of grip force (GF) and load force (LF). After a brain injury, the GF control is altered in the paretic hand but what happens with the non-paretic hand is still unclear. In this study, we compared the GF control and GF–LF coordination of the non-paretic hand of 10 stroke individuals who suffered right brain damage (RBD) and 10 who suffered left brain damage (LBD), with 20 healthy individuals during lifting and oscillation task, using an instrumented object. GF was recorded with a force transducer, and LF was estimated from the object weight and acceleration. Overall, the ipsilesional hand of stroke individuals, independent of the lesion side, presented similar GF control and GF–LF coordination. However, LBD individuals took longer to start lifting the object, which may be due to the need of more time to obtain somatosensory information from the contact with the object. The findings indicate that stroke individuals preserve their ability to control and coordinate GF and LF when using their ipsilesional hand for object manipulation and the left hemisphere may play an essential role in the processing of somatosensory information needed for the GF control.     

The Effect of Vision and Surface Compliance on Balance in Untrained and Strength Athletes

The purpose of this investigation was to evaluate the effect of the removal of vision and/or surface compliance on postural stability in strength athletes who habitually use free-weights and compound movements in their training (i.e., powerlifters, Olympic weightlifters), and untrained individuals. Static and dynamic balance testing was performed with eyes open or closed on stable and memory foam surfaces. Both groups had similar increases in postural sway area and velocity during quiet standing testing; whereas group main effects and interactions for dynamic testing revealed that untrained participants experienced greater relative declines in postural performance when voluntary limits of stability are stressed, especially when both vision and surface compliance were deterred. These results demonstrate that in comparison to untrained young adults, postural control variables may be reduced to a lesser extent in strength athletes when sensory constraints are altered; however this appears to be specific to the type of postural task performed.