Motor imagery effectiveness for mirror reversed movements

Physical practice is known to enhance motor adaptation skills, which refer to the individual ability to compensate for environmental changes. So far, it is still unknown whether a similar effect can be observed following motor imagery (MI). Thirty-nine participants were tested during a joystick tracking task under both normal and mirror conditions (i.e., the inductive direction of the joystick was reversed), before and after a physical practice or MI training phase. Eye movements and electromyographic activity were recorded during MI. Motor performance was also evaluated after a 6 h interval during daytime. As compared to the control group, the results revealed that both MI and physical practice improved motor performance in the mirror condition, during the post-training test. Furthermore, the time to complete the task was further reduced after 6 hours, both in the normal and mirror conditions. These results demonstrate the effectiveness of MI for learning mirror-reversed movements, and for the consolidation process that follows motor adaptation.     

Re-imagining motor imagery: building bridges between cognitive neuroscience and sport psychology

One of the most remarkable capacities of the mind is its ability to simulate sensations, actions, and other types of experience. A mental simulation process that has attracted recent attention from cognitive neuroscientists and sport psychologists is motor imagery or the mental rehearsal of actions without engaging in the actual physical movements involved. Research on motor imagery is important in psychology because it provides an empirical window on consciousness and movement planning, rectifies a relative neglect of non-visual types of mental imagery, and has practical implications for skill learning and skilled performance in special populations (e.g., athletes, surgeons). Unfortunately, contemporary research on motor imagery is hampered by a variety of semantic, conceptual, and methodological issues that prevent cross-fertilization of ideas between cognitive neuroscience and sport psychology. In this paper, we review these issues, suggest how they can be resolved, and sketch some potentially fruitful new directions for inter-disciplinary research in motor imagery.     

Is Mental Rotation Ability a Predictor of Success for Motor Performance?

Previous studies provided evidence of a relationship between mental rotation (MR) and motor processes in children and adults. However, there is no direct evidence that MR ability is a reliable predictor of success for motor performance. After completion of a MR test, the motor performance of 7- to 8-year-old and 11- to 12-year-old children was measured along a steeple chase and an equivalent straight distance sprint. The chase involved several motor actions requiring, among different competencies, spatial abilities such as performing a forward roll, jumping, crawling, turning, and changing directions. Data revealed that the time taken to complete the chase was influenced by speed and sex, but also by the individual MR ability. Based on these findings, we assume that MR and motor performance may share similar subprocesses.     

Hand mental rotation is not systematically altered by actual body position: Laterality judgment versus same–different comparison tasks

It is commonly believed that during mental rotation of body parts, participants tend to imagine their own body part moving toward the stimulus, thus using an egocentric strategy. Several studies have also shown that the mental rotation of hands is affected by the actual hand position, especially if the hand is kept in an awkward position. However, this hand posture effect, as well as the use of an egocentric strategy during mental rotation of body parts, is not systematic. Several experiments have demonstrated that manipulating the stimulus features or the paradigm could induce a shift to visual and allocentric strategies. Here, we studied the effects of hand posture and biomechanical constraints on one-hand mental rotation (laterality judgment task), two-hand mental rotation (same–different judgment task), and mental rotation of one or two alphanumeric symbols (control tasks). Effects of posture and biomechanical constraints were observed solely for the laterality judgment task. Response times in the same–different hand mental rotation items were influenced by the angular disparity between the stimuli. We interpreted our result as evidence of the use of different strategies for each task. Future research should focus on disentangling the exact subprocesses in which an egocentric strategy is used, in order to propose better tests for participants with motor impairments.     

Treadmill gait analysis does not detect motor deficits in animal models of Parkinson's disease or amyotrophic lateral sclerosis

Computerized treadmill gait analysis in models of toxicant exposure and neurodegenerative disorders holds much potential for detection and therapeutic intervention in these models, and researchers must validate the technology that assists in that data collection and analysis. The present authors used a commercially available computerized gait analysis system that used (a) a motorized treadmill on retired breeder male C57BL/6J mice, (b) the toxicant-induced (1-methyl-1-, 2-, 3-, 6-tetrahydropyridine) MPTP mouse model of Parkinson's disease (PD), and (c) the superoxide dismutase 1 (SOD1) G93A transgenic mouse model of amyotrophic lateral sclerosis (ALS). The authors compared the detection of deficits by computerized treadmill gait analysis in MPTP-treated mice with inked-paw stride length and correlated these measures to dopamine (DA) loss. The authors found that the computerized treadmill gait analysis system did not distinguish MPTP-treated mice from vehicle controls, despite a nearly 90% deficit of striatal DA. In contrast, decreases in inked-paw stride length correlated strongly with DA losses in these same animals. Computerized treadmill gait analysis could neither reliably distinguish SOD1 G93A mutant mice from controls from 6 to 12 weeks of age nor detect any consistent early motor deficits in these mice. On the basis of the authors' findings, they inferred that computerized gait analysis on a motorized treadmill is not suited to measuring motor deficits in either the MPTP mouse model of PD or the SOD1 G93A mouse model of ALS.     

The limits of selflessness: semantic relativism and the epistemology of de se thoughts

It has recently been proposed that the framework of semantic relativism be put to use to describe mental content, as deployed in some of the fundamental operations of the mind. This programme has inspired in particular a novel strategy of accounting for the essential egocentricity of first-personal or de se thoughts in relativist terms, with the advantage of dispensing with a notion of self-representation. This paper is a critical discussion of this strategy. While it is based on a plausible appeal to cognitive economy, the relativist theory does not fully account for the epistemic profile that distinguishes de se thinking, as some of its proponents hope to do. A deeper worry concerns the reliance of the theory on a primitive notion of “centre” that hasn’t yet received enough critical attention, and is ambiguous between a thin and a rich reading. I argue that while the rich reading is required if the relativist analysis of the de se is to achieve its most ambitious aims, it also deprives the theory of much of its explanatory power.     

How does motor imagery speed affect motor performance times? Evaluating the effects of task specificity

The present experiment investigated whether motor imagery (MI) performed at a faster speed might influence the actual motor performance duration by comparing real‐time vs. fast MI of different finger movement sequences. Forty‐eight participants were either asked to do real‐time or fast MI practice of simple 8‐digit (unimanual), complex 8‐digit (bimanual), and long (16‐digit) finger movement sequences. The main findings revealed that both fast and real‐time MI resulted in actual speed gains in all experimental conditions, hence suggesting that performing fast MI did not systematically provide additional benefits as compared to real‐time MI. Interestingly, the results suggested that the speed at which movements were performed following an increase in MI speed was selectively influenced by the complexity of the task. MI training at higher speed seemed to be more effective in changing complex motor sequences compared with real‐time MI. Practical implications in motor learning and rehabilitation are also discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

Duration of mentally simulated movement: a review

The authors review studies of mentally simulated movements. In automatic or cyclical movements, actual and motor imagery (MI) durations are similar. When athletes simulate only dynamic phases of movement or perform MI just before competing, however, environmental and time constraints lead to an underestimation of actual duration. Conversely, complex attention-demanding movements take longer to image. Finally, participants can modify the speed of MI voluntarily when they receive specific instructions. To complete the available data, the authors compared imagined and actual durations in tennis and gymnastics. Results showed systematic and disproportionate overestimation of actual duration. The authors found a relationship between complex motor skills and MI duration. They discuss the factors leading to over- and underestimation and the hypotheses that could be tested.     

Obsessive-compulsive symptoms and cigarette smoking: an initial cross-sectional test of mechanisms of co-occurrence

ABSTRACT

Tobacco addiction and obsessive-compulsive symptoms (OCS; intrusive thoughts or impulses that cause distress and rituals) are both mediated by compulsivity and negative reinforcement. Little evidence exists to guide theory, research, treatment, and population-based prevention of this co-occurrence. We propose a conceptual model of OCS-smoking co-occurrence in which smokers with elevated OCS capitalize on smoking to assuage OCS. This secondary analysis examined associations between OCS levels and self-reported smoking motives that are model-concordant: i) negative reinforcement—smoking for relief; ii) sensorimotor—benefits of behaviors and sensations of the tobacco self-administration ritual; and iii) habitual—smoking without conscious control. A community sample of cigarette smokers enrolled in a cessation trial (N = 458; 47.2% female; M _age = 36.9; SD = 13.6) completed pre-quit self-report measures of OCS levels and smoking motives. Regression models adjusted for sociodemographic covariates and non-OCS psychopathologies indicated that OCS level was positively associated with each model-concordant motive. OCS level was also correlated with tobacco dependence severity and greater withdrawal symptom severity experienced during previous quit attempts. Those with higher OCS report greater motivation to smoke for negative reinforcement, sensorimotor behavioral-ritualistic, habit/automaticity, and stimulation reasons. Further examination of the proposed model of OCS-smoking co-occurrence is warranted to guide theory and intervention for this population.     

Effects of Different Ratios of Physical and Mental Practice on Postural Control Improvement

Abstract

Mental practice (MP) is a reliable alternative or complement to physical practice (PP) for the training of postural control. We address how MP should ideally be combined with PP. Participants were assigned to four experimental groups where MP/PP ratios during training varied from 0 to 100%. Performance improved only for demanding postural adjustments, regardless of MP/PP ratio, and learning was partially consolidated after a night of sleep. Findings reinforce the relevance of MP for the training of weight shifting and further suggest that MP alone can be as efficient as PP for the learning of certain complex postural adjustments.