In search of the enactive: Introduction to special issue on enactive experience

Abstact In the decade and a half since the appearance of Varela, Thompson and Rosch's workThe Embodied Mind,enactivism has helped to put experience and consciousness, conceived of in a distinctive way, at the forefront of cognitive science. There are at least two major strands within the enactive perspective: a broad view of what it is to be an agent with a mind; and a more focused account of the nature of perception and perceptual experience. The relation between these two strands is discussed, with an overview of the papers presented in this volume.     

Qualitative analyses of critical aspects of adaptation to the visually left-right reversed world

In this article, mechanisms of perceptual adaptation to the transposed world are analyzed based on introspective and behavioral performance data gathered during an extended period of wearing left-right reversing goggles. Three aspects central to this study were the mental map of the living space surrounding the subject, body image (both seen and felt), and the sensorimotor coordination system, which reflects the relationship between the subject and surroundings. These were investigated through map-drawing tests, self-representation tests when postures other than face forward were adopted, and after effects observed immediately after removal of the reversing goggles. It was concluded that the main course of the perceptual adaptation to the visually left-right reversed world consists of double reversals of the mental map and body image as well as the establishment of a new sensorimotor coordination system. In sharp contrast to the proprioceptive-change hypothesis, the importance of the visual nature of the body image was emphasized.     

Comment on “Retention Characteristics of Motor Short-Term Memory Cues”

Marteniuk (1973) used negative results, which may be attributed to a lack of power, to question the adequacy of variable error as a measure of forgetting. He also used these negative results, along with constant error results which were consistent with the Laabs (1971, 1973) model of motor memory, to reject parts of the model related to variable error. Caution is advised when interpreting negative results and interchanging dependent measures.     

Short-Term Kinesthetic Training for Sensorimotor Rhythms: Effects in Experts and Amateurs

The authors’ aim was to examine whether short-term kinesthetic training affects the level of sensorimotor rhythm (SMR) in different frequency band: alpha (8–12 Hz), lower beta (12.5–16 Hz) and beta (16.5–20 Hz) during the execution of a motor imagery task of closing and opening the right and the left hand by experts (jugglers, practicing similar exercises on an everyday basis) and amateurs (individuals not practicing any sports). It was found that the performance of short kinesthetic training increases the power of alpha rhythm when executing imagery tasks only in the group of amateurs. Therefore, kinesthetic training may be successfully used as a method increasing the vividness of motor imagery, for example, in tasks involving the control of brain–computer interfaces based on SMR.     

Discordance in Recovery Between Altered Locomotion and Muscle Atrophy Induced by Simulated Microgravity in Rats

Exposure to a microgravity environment leads to adverse effects in motion and musculoskeletal properties. However, few studies have investigated the recovery of altered locomotion and muscle atrophy simultaneously. The authors investigated altered locomotion in rats submitted to simulated microgravity by hindlimb unloading for 2 weeks. Motion deficits were characterized by hyperextension of the knees and ankle joints and forward-shifted limb motion. Furthermore, these locomotor deficits did not revert to their original form after a 2-week recovery period, although muscle atrophy in the hindlimbs had recovered, implying discordance in recovery between altered locomotion and muscle atrophy, and that other factors such as neural drives might control behavioral adaptations to microgravity.     

The Force/Force-Variability Relationship Under Controlled Temporal Conditions

Previously, an inverted U relationship between force and force variability was demonstrated in both static and dynamic responses. Recent research suggests that the inverted U function may be due to a lack of control of the temporal aspects of the response. To investigate this hypothesis, we examined the relationship between force and force variability in rapid movements under controlled temporal conditions. Subjects (N = 4) made rapid reversal responses with a horizontal lever (using elbow flexion and extension) such that the time to reversal (160 ms) and the distance to reversal (45°) were held constant in each of six load conditions (either 0, .260, .520, .780,1.040, or 1.560 kg added to the lever). When time to reversal and time to peak acceleration were held constant, a curvilinear relationship between force and force variability resulted, suggesting that the inverted U function is related to control of the temporal aspects of the response.     

观念运动理论：内涵与证据

人类日常动作有两种类型, 一是是对外界刺激的反应, 是一种自下而上的动作模式, 即感觉运动(sensorimotor)模式; 二是以人们头脑中的观念意图为基础, 由观念引导, 为了实现一个特定的目标而执行特定的动作, 是一种自上而下的动作模式, 即观念运动(ideomotor)模式。观念运动理论(ideomotor theory)所解释的就是以基于意图的动作。该理论经历了长期的演变, 一般动作执行与动作模仿领域内的行为与神经科学研究的证据初步证实了观念运动的理论构想与主要机制：共同编码机制与镜像神经机制。观念运动理论在贯通感知觉与动作方面具有重大意义, 由此还产生了共享环路模型(shared circuits model, SCM)等新近观点。此外, 观念运动理论还强调了目标和预期的重要地位。未来还需加强对动作与意图之间的通路, 以及动作的本体性效果等方面的研究。     

Sensorimotor and working memory systems jointly support development of perceptual rhythm processing

We studied the role of sensorimotor and working memory systems in supporting development of perceptual rhythm processing with 119 participants aged 7–12 years. Children were assessed for their abilities in sensorimotor synchronization (SMS; beat tapping), auditory working memory (AWM; digit span), and rhythm discrimination (RD; same/different judgment on a pair of musical rhythm sequences). Multiple regression analysis revealed that children's RD performance was independently predicted by higher beat tapping consistency and greater digit span score, with all other demographic variables (age, sex, socioeconomic status, music training) controlled. The association between RD and SMS was more robust in the slower tempos (60 and 100 beats-per-minute (BPM)) than faster ones (120 and 180 BPM). Critically, the relation of SMS to RD was moderated by age in that RD performance was predicted by beat tapping consistency in younger children (age: 7–9 years), but not in older children (age: 10–12 years). AWM was the only predictor of RD in older children. Together, the current findings demonstrate that the sensorimotor and working memory systems jointly support RD processing during middle-to-late childhood and that the degree of association between the two systems and perceptual rhythm processing is shifted before entering into early adolescence.     

建立新一代的精神分裂症动物模型

精神分裂症动物模型的建立与发展,是当前探索精神分裂症的神经生物学和认知心理学机制的一个关键课题。在加工-保护理论的基础上所建立起来的感觉运动门控精神分裂症模型一直受到普遍的关注。然而,高级认知活动是如何对感觉门控进行调节的这一核心问题目前还有待进一步的解决。本综述围绕着这个核心问题,系统地解释为什么惊反射前脉冲抑制成为目前最为流行的一种精神分裂症的模型,并介绍恐惧情绪学习对感觉运动门控调节作用的最新研究成果,以及阐述这种自上而下的调节作用如何受到在早期发育阶段的社会隔离的影响