视觉预期和注意指向对姿势和动作肌肉预期和补偿姿势调节的影响

采用经典落球试验研究范式,同步观察视觉预期和注意指向对腰部姿势肌肉和上肢运动肌肉预期和补偿姿势调节的影响,探索视觉预期和注意指向影响姿势控制的早期心理生理机制。24名青年志愿者(10名男性,14名女性)参与完成本实验,分别在有、无视觉预期以及注意指向"托盘稳定"或者"重心稳定"的实验条件下观察外部姿势干扰对腰部姿势肌肉(L5~S1腰部多裂肌)和上肢动作肌肉(肱二头肌)预期姿势调节(anticipatory postural adjustments,APAs)和补偿姿势调节(compensatory postural adjustments,CPAs)相关时间和强度参数的影响。APAs和CPAs的时间和强度参数通过获取被检肌肉s EMG信号并参照相关检测规范进行。结果显示:(1)视觉预期对多裂肌的APAs启动时间,对肱二头肌的APAs启动时间、APAs强度和CPAs强度有显著影响;(2)注意指向对多裂肌的CPAs启动时间和肱二头肌APAs启动时间有显著影响;(3)视觉预期和注意指向对肱二头肌的APAs启动时间和APAs强度有交互作用。研究认为,突发外部姿势干扰条件下姿势肌肉和动作肌肉的姿势调节策略具有一定的差异,视觉预期和注意指向仅对姿势肌肉的时间参数有影响,对动作肌肉APAs和CPAs时间和强度参数都产生调节作用,表明在中枢神经系统的姿势控制中,人体姿势策略的调节是通过对姿势肌肉和动作肌肉的双重控制来完成的,视觉预期效应和心理指向效应反映在对不同功能肌肉前馈控制和反馈控制相应参数的调节。     

神经肌肉下意识前馈与反馈控制的知觉线索效应

为研究视觉和时间知觉线索对突发外部姿势干扰下中枢神经系统对动作肌肉和姿势肌肉预期姿势调节(APAs)和补偿姿势调节(CPAs)的影响, 本研究被试分别在视觉和时间线索引导下完成经典落球试验, 同步采集右侧动作肌肉肱二头肌和姿势肌肉腰部竖脊肌和腰部多裂肌的sEMG信号, 计算被检肌肉APAs发生率、预激活时间和CPAs反应强度。结果发现, 视觉线索可以引发动作肌肉和姿势肌肉APAs发生率明显增加, 预激活时间明显提前, 以及动作肌肉CPAs反应强度明显减小; 而时间线索主要引发动作肌肉预激活提前, 对姿势肌肉APAs和CPAs无明显影响。该结果表明, 视觉和时间引导线索对突发外部姿势干扰条件下人体姿势肌肉和动作肌肉的中枢运动控制具有不同的作用。视觉引导线索能够明显增加姿势肌肉和动作肌肉预激活发生率和提早预激活时间, 表现出明显的“视觉线索预激活优势现象”; 而时间引导线索主要引发动作肌肉预激活提前, 对姿势肌肉APAs和CPAs无明显影响。     

身体姿势的心理效应：基于具身视角

具身视角下，姿势可以对心理产生影响。梳理了广受关注的“直立”和“蜷曲”、“扩张”和“收缩”、“水平”和“垂直”等姿势的效应研究成果，并对神经肌肉反馈理论、自我知觉理论、情境认知理论等姿势效应的内在机制进行总结和评价。指出在实验范式、姿势控制、效应稳定性以及深层机制探析等方面存在的局限和未来方向，认为姿势效应的神经机制、时程变化、个体差异及姿势的心理调节功能等将会成为研究热点。     

认知判断中手部动作模拟的fMRI研究

该研究采用功能磁共振成像技术,考察不同条件下进行工具认知判断时手部姿势对认知判断的影响及动作模拟的神经机制。实验发现：手部姿势存在显著的主效应,冲突手部姿势条件下反应时最慢,且冲突手部姿势条件下与不冲突手部姿势条件下、自然状态条件下反应时存在显著差异,自然状态条件与不冲突手部姿势条件下反应时不存在显著差异。另外,f MRI成像结果发现,额中回、额下回、顶下小叶以及辅助运动区在自然状态下有显著激活,表明个体在进行认知判断过程中有动作模拟过程;海马结构、扣带回及楔前叶等与记忆有关的脑区有显著激活,表明身体经验在认知过程的作用。总的研究表明,不同的手部姿势状态对认知判断有不同影响,冲突手部姿势会对动作模拟产生干扰作用,手部动作模拟的神经机制主要涉及镜像神经元区,且在认知判断时存在具身效应。     

心理预期与认知方式对负面情绪的交互调节

近年来, 研究发现对负性事件发生之前预先的心理准备, 即心理预期, 能有效降低负性事件发生后的情绪影响, 但预期过程本身却导致情绪相关神经环路的激活与主观焦虑体验。因此, 采用适应性认知调节方式克服预期过程本身的负面情绪效应, 以充分发挥事先预期的情绪调控优势, 成为情绪调节领域亟待解决的问题。另一方面, 过度负性预期--对潜在负性事件不仅作负面心理预期同时以情绪化的认知方式应对该事件, 是焦虑障碍的核心特征。因此, 对焦虑症患者进行适应性认知方式的训练以消除其情绪化应对方式, 最终减弱该人群对未知事件的过度负面预期, 可能是焦虑障碍干预的重要途径。因此, 有必要综合行为学, 多导外周生理记录与神经成像手段以揭示认知方式与心理预期对负面情绪的交互调节效应; 旨在探求发挥心理预期情绪调节优势, 减弱其情绪代价的方法; 并为焦虑症的临床治疗提供新的思路。     

现实预期和意愿预期在文本阅读中的激活强度

文本阅读中,读者往往对事件的后续发展进行预期推理。预期推理有两种倾向,要么是倾向于根据客观现实条件进行的现实预期,要么是倾向于根据主观个人意愿进行的意愿预期。两个实验探讨了文本阅读中读者产生的现实预期和意愿预期的激活强度。结果发现,现实预期和意愿预期都可以在阅读中即时产生,意愿预期强于现实预期;把读者分为"情感导向型"和"非情感导向型",发现"情感导向型"的读者,阅读过程中产生的意愿预期强于现实预期,而"非情感导向型"的读者则不是。     

左前额叶与趋近动机加工的关系

在加工正性情绪时, 前额叶左侧激活水平大于右侧。而正性情绪往往伴随着趋近动机。因此为了探索这种现象反映的究竟是正性情绪加工还是趋近动机加工, 文章总结了两个研究领域中的有关证据：来自特质或状态愤怒情绪与左前额叶相对激活关系领域的研究证据和来自身体姿势变化(包括整体姿势变化和单侧肌肉紧缩)对左前额叶相对激活的影响领域的研究证据。前者的一致发现是：左前额叶参与加工由愤怒情绪引发的趋近动机。后者的一致发现是：不同的身体姿势能够改变左前额叶的相对激活水平。两种领域的研究证据汇聚起来证明左前额叶参与加工趋近动机。文章还指出了将来研究的注意事项和可能方向：精确定义回避型愤怒; 探索愤怒情绪是否在加工晚期诱发趋近或回避动机; 探索不同方式诱发的趋近动机是否在脑机制上存在差异。     

编码后奖赏影响基于议程的学习：奖赏预期和结果的作用

基于ABR模型考察奖赏预期和奖赏结果对不同难度词对记忆与元记忆的影响。结果发现：(1)限时学习条件下,奖赏结果促进不同难度词对记忆成绩和学习判断,奖赏预期仅提高简单词对的记忆成绩。(2)自定步调学习条件下,定时学习判断时奖赏结果仅影响学习判断;奖赏预期促进高难度词对的学习时间分配,从而提高记忆成绩和学习判断。(3)在自定步调学习时,奖赏预期超越难度成为影响学习时间分配的因素。以上结果表明,个体会综合奖赏预期、奖赏结果和难度构建学习议程,足够大的奖赏预期会超越难度成为议程构建的主导因素。但奖赏预期和奖赏结果对记忆成绩、学习时间分配和学习判断的影响受学习条件调节。     

预期反差的社会效应与管理

预期反差是主体对未来发展的预期与未来发展的实际状况之间的差距.经济发展由高速到平缓的变化,会导致公众的预期由正向反差向负向反差转变.预期反差的这种转变会影响公众的情绪、评价和行动.中国正在面临公众的预期反差从正向到负向的转变.应对预斯反差转变所带来的冲击,需要合理进行预期管理.     

现阶段我国城市居民消费心理预期的性质与特点

采用自编《消费心理预期问卷》对1097名城市被试进行了研究,结果表明：1．《消费心理预期问卷》具有较高的信度和效度;2．消费心理预期是由五个因素构成的：宏观经济形势预期、个人生活与收入预期、政府经济政策预期、物价走势预期和突发事件预防预期;3．现阶段,我国城市居民的消费心理预期普遍比较消极．甚至悲观;4．影响消费心理预期的因素是多维的,其中?肖费者的性别、年龄、学历、工作单位和所在城市等变量都是直接影响心理预期的一些重要因素,即不同性别、年龄、学历、工作单位和城市的消费者对未来存在着不同的心理预期。     

Effects of vision and cognitive load on anticipatory and compensatory postural control

This study assessed the effects of vision and cognitive load on anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) in response to an externally triggered postural perturbation. A ball-hitting test was repeated under different visual conditions (eyes open, EO; eyes closed, EC) and cognitive loads (no load, 3-subtraction task, time-limited 3-subtraction task). Data were collected separately for I) surface electromyography from the right side of the biceps brachii (BIC) and erector spinae (ES) to detect the latency and response intensity (RI); and II) displacement of the centre of pressure (ΔCOP) to detect the standard deviation (ΔCOP_SD) and maximum value (ΔCOP_max) in the anterior-posterior direction. Compared with the results under the EC condition, the ES latency was shorter and the RI of the BIC was lower under the EO condition. Accordingly, the ΔCOP_SD and ΔCOP_max were increased in the APAs phase and decreased in the CPAs phase. Cognitive load had no effect on APAs and CPAs or on ΔCOP in the APAs phase. However, ΔCOP_max was decreased in the CPAs phase during the EC condition. In conclusion, vision played an important role in APAs and CPAs for muscle activation and ΔCOP. Cognitive load had no effect on neuromuscular APAs or CPAs except when the postural perturbation occurred when visually unexpected.     

The role of predictability of the magnitude of a perturbation in control of vertical posture when catching an object

The predictability of perturbation magnitude plays an important role in control of standing posture. The aim of the study was to examine anticipatory (APAs) and compensatory (CPAs) postural adjustments in response to catching objects of uncertain mass. Twenty adults caught the same object with either light or heavy weight placed in it. Electromyographic activity of eight trunk and leg muscles, displacements of the center of pressure, and angular displacement of the shoulder joint were recorded and analyzed during the APAs and CPAs intervals. When the subjects experienced repeated catching of the object with the same weight, they estimated the object mass beforehand and generated APAs more precisely. When the object mass changed unpredictably, they generated APAs based on the most recent catch and needed four to six trials to optimize APAs and CPAs. The muscle co-contraction was a primary pattern for catching the object of uncertain mass. The results of the study suggest that catching the object of uncertain mass is a challenging task that involves co-contraction of postural muscles to maintain balance.     

Effects of Varying Load Conditions on the Organization of Postural Adjustments during Voluntary Arm Flexion

One purpose of the experiments reported here was to further clarify the effect of varying loads on postural adjustments. Another was to reevaluate whether or not the timing of electromyographic (EMG) activity in the postural muscle is preprogrammed. To accomplish these goals, we compared the effect of the presence or absence of prior knowledge of a load on the timing of EMG activity in the postural muscle (biceps femoris [BF]) with that in the focal muscle (anterior deltoid [AD]). Although the sequence of EMG activation was similar under conditions with and without a load, the timing of postural EMG activities (BFi, ipsilateral BF; BFc, contralateral BF) in associated postural adjustments was dependent on the force of arm movement, and the latencies of postural EMG activities (BFi—BFc) were dependent on the speed of arm movement. This indicates that EMG changes in the upper (focal muscle) and lower limbs (postural muscle) were triggered by different motor programs. Moreover, similar EMG activities were observed in postural muscles when the subject had advance knowledge of the presence or the absence of a load. Thus, this suggests that BFi may be centrally preprogrammed (anticipatory regulation) and BFc may be feedback regulated. Furthermore, environmental information may be a critical source of influence on those postural responses.     

Harnessing the Power of a Novel Program for Dynamic Balance Perturbation with Supported Body Weight

Abstract

Self-initiated postural adjustments commonly occur in daily life. To accessibly measure this type of dynamic balance, we developed a simple computer program to induce virtual perturbations and combined it with a commercially available balance board and portable EMG system to measure resulting self-initiated postural adjustments. When performing perturbed balance tests, safety harness with body weight support (BWS) is often used. However, influences of these harnesses on postural reactions are not well known. This study investigated the sensitivity of our assessment tool under different BWS conditions and muscle responses during postural adjustments following perturbation at different directions. Fifteen neurologically intact participants performed self-initiated postural adjustments under conditions with: (1) no harness; (2) harness with no BWS; and (3) harness with 10% BWS. Postural adjustment time and muscle activities of the lower leg were measured. We observed significant increases in postural adjustment time in the harness with no BWS condition and differneces in lower leg muscles response to virtual perturbation. Our findings suggest that the combination of our customized program with EMG is a sensitive and convenient tool to measure postural adjustments that approximate real-world scenarios. This method can be used with light body weight support to ensure safety without influencing muscle synergies.     

Effects of varying load conditions on the organization of postural adjustments during voluntary arm flexion

One purpose of the experiments reported here was to further clarify the effect of varying loads on postural adjustments. Another was to reevaluate whether or not the timing of electromyographic (EMG) activity in the postural muscle is preprogrammed. To accomplish these goals, we compared the effect of the presence or absence of prior knowledge of a load on the timing of EMG activity in the postural muscle (biceps femoris [BF]) with that in the focal muscle (anterior deltoid [AD]). Although the sequence of EMG activation was similar under conditions with and without a load, the timing of postural EMG activities (BFi, ipsilateral BF; BFc, contralateral BF) in associated postural adjustments was dependent on the force of arm movement, and the latencies of postural EMG activities (BFi-BFc) were dependent on the speed of arm movement. This indicates that EMG changes in the upper (focal muscle) and lower limbs (postural muscle) were triggered by different motor programs. Moreover, similar EMG activities were observed in postural muscles when the subject had advance knowledge of the presence or the absence of a load. Thus, this suggests that BFi may be centrally preprogrammed (anticipatory regulation) and BFc may be feedback regulated. Furthermore, environmental information may be a critical source of influence on those postural responses.     

Individuals with chronic ankle instability compensate for their ankle deficits using proximal musculature to maintain reduced postural sway while kicking a ball

The aim of this study was to investigate anticipatory (APA), simultaneous (SPA) and compensatory (CPA) postural adjustments in individuals with and without chronic ankle instability (CAI) as they kicked a ball while standing in a single-leg stance on a stable and unstable surface. Electromyographic activity (EMG) of postural muscles and center of pressure (COP) displacements were calculated and their magnitudes analyzed during the postural adjustment intervals. Additionally, the COP area of sway was calculated over the duration of the whole task. The activities of postural muscles were also studied using principal component analysis (PCA) to identify between-group differences in patterns of muscle activation. The individuals with CAI showed reduced magnitude of EMG at the muscles around the ankle while around the hip the activity was increased. These were associated with a reduction in balance sway across the entire task, as compared with the control group. The PCA revealed that CAI participants assemble different sets of muscle activation to compensate for their ankle instability, primarily activating hip/spine muscles. These results set up potential investigations to examine whether balance control interventions enhance these adaptations or revert them to a normal pattern as well as if any of these changes proactively address recurrent ankle sprain conditions.     

Postural and focal inhibition of voluntary movements prepared under various temporal constraints

Large disturbances arising from the moving segments (focal movement) are commonly counteracted by anticipatory postural adjustments (APAs). The aim of this study was to investigate how APAs – focal movement coordination changes under temporal constraint. Ten subjects were instructed to perform an arm raising movement in the reactive (simple reaction time) and predictive (anticipation–coincidence) tasks. A stop paradigm was applied to reveal the coordination. On some unexpected trials, a stop signal indicated to inhibit the movement; it occurred randomly at different delays (SOA) relative to the go signal in the reactive task, and at different delays prior to the focal response initiation in the predictive task. Focal movement was measured using contact switch, accelerometer and EMG from the anterior deltoid. APAs were quantified using centre of pressure displacement and EMG from three postural muscles. The inhibition rates as a function of the SOA produce psychometric functions where the bi-serial points allow the moment of the motor "command release" to be estimated. Repeated measures ANOVAs showed that APAs and focal movement were closely timed in the reactive task but distinct in a predictive task. Data were discussed according to two different models of coordination: (1) hierarchical model where APAs and focal movement are the results of a single motor command; (2) parallel model implying two independent motor commands. The data clearly favor the parallel model when the temporal constraint is low. The stop paradigm appears as a promising technique to explore APAs – focal movement coordination.     

Anticipatory Postural Adjustments for Altering Direction During Walking

The authors examined how individuals adapt their gait and regulate their body configuration before altering direction during walking. Eight young adults were asked to change direction during walking with different turning angles (0deg;, 45deg;, 90deg;), pivot foot (left, right), and walking speeds (normal and fast). The authors used video and force platform systems to determine participants' whole-body center of mass and the center of pressure during the step before they changed direction. The results showed that anticipatory postural adjustments occurred during the prior step and occurred earlier for the fast walking speed. Anticipatory postural adjustments were affected by all 3 variables (turn angle, pivot foot, and speed). Participants leaned backward and sideward on the prior step in anticipation of the turn. Those findings indicate that the motor system uses central control mechanisms to predict the required anticipatory adjustments and organizes the body configuration on the basis of the movement goal.