Showing papers on "Motor imagery published in 2009"
TL;DR: Although the existing evidence is limited by poor trial designs, some treatments do show promise for improving motor recovery, particularly those that have focused on high-intensity and repetitive task-specific practice.
Abstract: Loss of functional movement is a common consequence of stroke for which a wide range of interventions has been developed. In this Review, we aimed to provide an overview of the available evidence on interventions for motor recovery after stroke through the evaluation of systematic reviews, supplemented by recent randomised controlled trials. Most trials were small and had some design limitations. Improvements in recovery of arm function were seen for constraint-induced movement therapy, electromyographic biofeedback, mental practice with motor imagery, and robotics. Improvements in transfer ability or balance were seen with repetitive task training, biofeedback, and training with a moving platform. Physical fitness training, high-intensity therapy (usually physiotherapy), and repetitive task training improved walking speed. Although the existing evidence is limited by poor trial designs, some treatments do show promise for improving motor recovery, particularly those that have focused on high-intensity and repetitive task-specific practice.
1,810 citations
TL;DR: Findings support the notion that mental training procedures can be applied as a therapeutic tool in rehabilitation and in applications for power training.
634 citations
TL;DR: The results suggest that VI and KI are mediated through separate neural systems, which contribute differently during processes of motor learning and neurological rehabilitation.
Abstract: Although there is ample evidence that motor imagery activates similar cerebral regions to those solicited during actual movements, it is still unknown whether visual (VI) and kinesthetic imagery (KI) recruit comparable or distinct neural networks. The present study was thus designed to identify, through functional magnetic resonance imaging at 3.0 Tesla in 13 skilled imagers, the cerebral structures implicated in VI and KI. Participants were scanned in a perceptual control condition and while physically executing or focusing during motor imagery on either the visual or kinesthetic components of an explicitly known sequence of finger movements. Subjects' imagery abilities were assessed using well-established psychological, chronometric, and new physiological measures from the autonomic nervous system. Compared with the perceptual condition, physical executing, VI, and KI resulted in overlapping (albeit non-identical) brain activations, including motor-related regions and the inferior and superior parietal lobules. By contrast, a divergent pattern of increased activity was observed when VI and KI were compared directly: VI activated predominantly the occipital regions and the superior parietal lobules, whereas KI yielded more activity in motor-associated structures and the inferior parietal lobule. These results suggest that VI and KI are mediated through separate neural systems, which contribute differently during processes of motor learning and neurological rehabilitation.
458 citations
TL;DR: It is demonstrated that visual BCI feedback clearly modulates sensorimotor EEG rhythms, and the presentation form (abstract versus realistic) does not influence the performance in a BCI, at least in initial training sessions.
363 citations
TL;DR: How far does recovery of motor performance depend on the processes that precede movement execution involving the premotor and prefrontal cortex, rather than recovery of the corticospinal system alone?
Abstract: The human brain reorganizes itself throughout life, in health and disease. This neuroplasticity not only underpins human adaptation and learning,1 but is especially important for recovery after brain injury. Understanding and influencing the processes of neuroplasticity are therefore crucial in providing more effective therapies for patients. Functional neuroimaging can reveal the alterations in large-scale brain networks following brain injury,2,3 physical training,4–6 and pharmacological therapy.7
After a subcortical stroke, functional magnetic resonance imaging (fMRI) during movement reveals cortical reorganization that is associated with the recovery of function.8–10 The reorganization includes overactivity of cortical motor areas,11 alterations in the inter-hemispheric balance,4,9,12–15 and dysfunctional coupling between cortical regions.10,16 However, the cortical activation patterns associated with some motor tasks may appear normal in patients despite residual functional impairment.11,13,14,17–19 An explanation for this paradox is that hemiparetic stroke disrupts both corticospinal output and important motor processes prior to the execution of movement, for example, motor attention, imagination, preparation, or planning.18,20
We set out to examine the extent to which recovery of motor performance after stroke is associated with changes in the movement-related cognitive processes that precede movement, as opposed to changes in corticospinal function. There are 3 key aspects to our study. First, we studied a carefully selected subgroup of patients with a left hemisphere subcortical stroke. Changes in their cortical motor systems are therefore not confounded by cortical infarction, and can be interpreted as remote neuroplasticity. Second, we studied both motor imagery (MI) and executed movement (EM). Motor imagery utilizes many aspects of the motor system,21–24 and has been suggested as an adjunct to rehabilitative physical therapies as well as a method to study the motor system without actual movement. For example, in stroke patients with normal activations during executed movement, motor imagery has been associated with abnormal hemispheric lateralization that in turn correlated with recovery of motor function.20 The third critical aspect was that rather than simply defining the activation within isolated regions, we analyzed the interactions between brain regions by structural equation modeling of the fMRI signal in an anatomically specified causal model.25,26 Inferences about changing regional neuronal interactions can be made from the changing interactions at the level of blood oxygenation level-dependent (BOLD) fMRI signals.27,28 In the absence of significant neuronal loss or regeneration, such changes in connectivity are heavily dependent on changes in synaptic density, structure, and efficacy.29 Inferences can be drawn in terms of changes in systems-level effective connectivity, in which the strength of a physiological connection between 2 regions (eg, path coefficient) is modulated by experimental context (eg, MI vs EM) and/or condition effects (eg, patient group).
We used fMRI to examine the connectivity within the extended motor network during motor imagery and executed movement in subcortical stroke patients who were nearly fully recovered. Our first hypothesis was that although activations may normalize after stroke, analysis of effective connectivity would reveal persisting abnormalities. Our second hypothesis was that atypical connectivity will be more prominent during motor imagery than executed movement, because of the emphasis on the cognitive processes that precede movement execution. Finally, we predicted that connectivity among prefrontal and premotor cortex would correlate with upper limb motor function.
251 citations
TL;DR: The proposed neurofeedback-based motor imagery training system can help individuals get the feel of motor imagery by presenting them with real-time brain activation maps on their cortex and will be useful not only for BCI applications, but for functional brain mapping studies that utilize motor imagery tasks as well.
228 citations
TL;DR: The present study investigated whether proprioceptive information on hand position is integrated similarly in 1PP and 3PP imagery of hand movements and showed stronger activation in left hemisphere motor and motor-related structures on 1PP compared with 3PP trials.
Abstract: It is assumed that imagining oneself from a first-person perspective (1PP) is more embodied than a third-person perspective (3PP). Therefore, 1PP imagery should lead to more activity in motor and motor-related structures, and the postural configuration of one's own body should be particularly relevant in 1PP simulation. The present study investigated whether proprioceptive information on hand position is integrated similarly in 1PP and 3PP imagery of hand movements. During functional magnetic resonance imaging (fMRI) scanning, 20 right-handed female college students watched video sequences of different hand movements with their right hand in a compatible versus incompatible posture and subsequently performed 1PP or 3PP imagery of the movement. Results showed stronger activation in left hemisphere motor and motor-related structures, especially the inferior parietal lobe, on 1PP compared with 3PP trials. Activation in the left inferior parietal lobe (parietal operculum, SII) and the insula was stronger in 1PP trials with compatible compared with incompatible posture. Thus, proprioceptive information on actual body posture is more relevant for 1PP imagery processes. Results support the embodied nature of 1PP imagery and indicate possible applications in athletic training or rehabilitation.
157 citations
TL;DR: An rtfMRI-based brain-machine interface (BMI) whereby 2-dimensional movement of a robotic arm was controlled by the regulation of regional cortical activations in the primary motor areas.
156 citations
TL;DR: It is proposed that covert activity in the human motor cortex may reflect different aspects of motor behavior, and MEP amplitudes, regardless of pliers used, reflected the muscular pattern involved in the execution of the observed action.
Abstract: We recorded motor-evoked potentials (MEPs) to transcranial magnetic stimulation from the right opponens pollicis (OP) muscle while participants observed an experimenter operating two types of pliers: pliers opened by the extension of the fingers and closed by their flexion ("normal pliers") and pliers opened by the flexion of the fingers and closed by their extension ("reverse pliers"). In one experimental condition, the experimenter merely opened and closed the pliers; in the other, he grasped an object with them. In a further condition, the participants imagined themselves operating the normal and reverse pliers. During the observation of actions devoid of a goal, the MEP amplitudes, regardless of pliers used, reflected the muscular pattern involved in the execution of the observed action. In contrast, during the observation of goal-directed actions, the MEPs from OP were modulated by the action goal, increasing during goal achievement despite the opposite hand movements necessary to obtain it. During motor imagery, the MEPs recorded from OP reflected the muscular pattern required to perform the imagined action. We propose that covert activity in the human motor cortex may reflect different aspects of motor behavior. Imagining oneself performing tool actions or observing tool actions devoid of a goal activates the representation of the hand movements that correspond to the observed ones. In contrast, the observation of tool actions with a goal incorporates the distal part of the tool in the observer's body schema, resulting in a higher-order representation of the meaning of the motor act.
151 citations
TL;DR: The case that modulation of alpha activity by means of covert spatial attention is promising as a control signal for a two-dimensional BCI is supported.
151 citations
13 Nov 2009
TL;DR: Evidence is provided that BCI-driven robotic rehabilitation is effective in restoring motor control for stroke by investigating the effects of MI-BCI for upper limb robotic rehabilitation compared to standard robotic rehabilitation.
Abstract: Non-invasive EEG-based motor imagery brain-computer interface (MI-BCI) holds promise to effectively restore motor control to stroke survivors. This clinical study investigates the effects of MI-BCI for upper limb robotic rehabilitation compared to standard robotic rehabilitation. The subjects are hemiparetic stroke patients with mean age of 50.2 and baseline Fugl-Meyer (FM) score 29.7 (out of 66, higher = 3D better) randomly assigned to each group respectively (N = 3D8 and 10). Each subject underwent 12 sessions of 1-hour rehabilitation for 4 weeks. Significant gains in FM scores were observed in both groups at post-rehabilitation (4.9, p = 3D0.001) and 2-month post-rehabilitation (4.9, p = 3D0.002). The experimental group yielded higher 2-month post-rehabilitation gain than the control (6.0 versus 4.0) but no significance was found (p = 3D0.475). However, among subjects with positive gain (N = 3D6 and 7), the initial difference of 2.8 between the two groups was increased to a significant 6.5 (p = 3D0.019) after adjustment for age and gender. Hence this study provides evidence that BCI-driven robotic rehabilitation is effective in restoring motor control for stroke.
TL;DR: In well-recovered subcortical stroke, the motor system, including ipsilesional BA4, is activated during MI despite the lesion, however, it remains disorganized in proportion to residual motor impairment.
Abstract: Background and Purpose— In recovered subcortical stroke, the pattern of motor network activation during motor execution can appear normal or not, depending on the task. Whether this applies to other aspects of motor function is unknown. We used functional MRI to assess motor imagery (MI), a promising new approach to improve motor function after stroke, and contrasted it to motor execution. Methods— Twenty well-recovered patients with hemiparetic subcortical stroke (14 males; mean age, 66.5 years) and 17 aged-matched control subjects were studied. Extensive behavioral screening excluded 8 patients and 4 control subjects due to impaired MI abilities. Subjects performed MI and motor execution of a paced finger–thumb opposition sequence using a functional MRI paradigm that monitored compliance. Activation within the primary motor cortex (BA4a and 4p), dorsal premotor, and supplementary motor areas was examined. Results— The pattern of activation during affected-hand motor execution was not different from cont...
TL;DR: It is demonstrated that more brain regions showed effective connections to the SMA during the right-hand motor imagery than during the left- hand motor imagery, but the strength of the casual influence during theLeft-hand Motor Imagery was stronger than that of theRight-handMotor imagery.
TL;DR: Elderly subjects were affected in their ability to implicitly simulate movements of the upper limbs, especially those requiring the largest amplitude of displacement and/or with strong biomechanical constraints, and a general decline in action simulation occurs with normal aging, in particular for the non-dominant side of the body.
Abstract: Background
Normal aging significantly influences motor and cognitive performance. Little is known about age-related changes in action simulation. Here, we investigated the influence of aging on implicit motor imagery.
TL;DR: It is argued that movement imagery reflects the unfolding of internal modeling processes providing the foundation for adaptive, goal-directed movements, which is entwined with the development of movement skill in children.
Abstract: Motor imagery provides a unique window on the integrity of movement representation. How this ability unfolds during development remains unknown, however. It was the aim of this cross-sectional study to chart the development of movement imagery over childhood using validated measures, and to examine its relationship to movement skill. A sample of 58 children aged 7-12 years were recruited from Australian primary schools. Motor imagery ability was assessed using the Radial Pointing Task and a (mental) Hand Rotation Task, whereas visual (or object-related) imagery was measured on a Letter Rotation Task. Motor skill was assessed on the McCarron Assessment of Neuromuscular Development (MAND). Results showed clear age differences on all measures: motor skill, motor imagery, and visual imagery. The relationship between motor imagery and motor skill was shown to become stronger with age, whereas no relationship between visual imagery and motor skill was evident at any age. Taken together, these results show that motor imagery has a distinct developmental trajectory that is entwined with the development of movement skill in children. We argue that movement imagery reflects the unfolding of internal modeling processes providing the foundation for adaptive, goal-directed movements.
TL;DR: It is concluded that motor imagery involves the generation of an action plan that is grounded in the participant's motor habits, not just an abstract representation at the level of the action's goal.
Abstract: If motor imagery uses neural structures involved in action execution, then the neural correlates of imagining an action should differ between individuals who tend to execute the action differently. Here we report fMRI data showing that motor imagery is influenced by the way people habitually perform motor actions with their particular bodies; that is, motor imagery is ‘body-specific’ (Casasanto, 2009). During mental imagery for complex hand actions, activation of cortical areas involved in motor planning and execution was left-lateralized in right-handers but right-lateralized in left-handers. We conclude that motor imagery involves the generation of an action plan that is grounded in the participant’s motor habits, not just an abstract representation at the level of the action’s goal. People with different patterns of motor experience form correspondingly different neurocognitive representations of imagined actions.
TL;DR: The resulting concept of functional equivalence between MIm and execution opens a window to study the organization of motor processes and, more generally, to understand the neural plasticity of the motor system.
Abstract: In the neurosciences, motor imagery (MIm) has not just been a topic of basic research. It has also attracted attention in applied research as a therapeutic tool. MIm is conceptualized as an internal simulation of motor acts that generates images on the basis of motor representations. Therefore, MIm is associated with neural activation of the cortical and subcortical motor system. The resulting concept of functional equivalence between MIm and execution opens a window to study the organization of motor processes and, more generally, to understand the neural plasticity of the motor system.
13 Nov 2009
TL;DR: 3 approaches of multi-class extension to the FBCSP algorithm are proposed: One-versus-Rest, Pair-Wise and Divide-and-Conquer, which decompose the multi- class problem into several binary-class problems.
Abstract: This paper investigates the classification of multi-class motor imagery for electroencephalogram (EEG)-based Brain-Computer Interface (BCI) using the Filter Bank Common Spatial Pattern (FBCSP) algorithm. The FBCSP algorithm classifies EEG measurements from features constructed using subject-specific temporal-spatial filters. However, the FBCSP algorithm is limited to binary-class motor imagery. Hence, this paper proposes 3 approaches of multi-class extension to the FBCSP algorithm: One-versus-Rest, Pair-Wise and Divide-and-Conquer. These approaches decompose the multi-class problem into several binary-class problems. The study is conducted on the BCI Competition IV dataset IIa, which comprises single-trial EEG data from 9 subjects performing 4-class motor imagery of left-hand, right-hand, foot and tongue actions. The results showed that the multi-class FBCSP algorithm could extract features that matched neurophysiological knowledge, and yielded the best performance on the evaluation data compared to other international submissions.
TL;DR: The mental representation of actions is highly modulated by imagery practice and motor activities, and the ability to generate vivid images of movements can be specifically weakened by limb loss or disuse, but lack of movement does not affect the temporal characteristics of motor imagery.
Abstract: Background. The ability to generate vivid images of movements is variable across individuals and likely influenced by sensorimotor inputs. Objectives. The authors examined (1) the vividness of motor imagery in dancers and in persons with late blindness, with amputation or an immobilization of one lower limb; (2) the effects of prosthesis use on motor imagery; and (3) the temporal characteristics of motor imagery. Methods. Eleven dancers, 10 persons with late blindness, 14 with amputation, 6 with immobilization, and 2 groups of age-matched healthy individuals (27 in control group A; 35 in control group B) participated. The Kinesthetic and Visual Imagery Questionnaire served to assess motor imagery vividness. Temporal characteristics were assessed with mental chronometry. Results. The late blindness group and dance group displayed higher imagery scores than respective control groups. In the amputation and immobilization groups, imagery scores were lower on the affected side than the intact side and specific...
TL;DR: A novel motor imagery based self-paced BCI paradigm for controlling a simulated robot in a specifically designed environment which is able to provide user’s control intention and timing during online experiments is proposed so that online training and adaptation of the motor imagery Based BCI can be effectively investigated.
Abstract: Due to the non-stationarity of EEG signals, online training and adaptation are essential to EEG based brain–computer interface (BCI) systems. Self-paced BCIs offer more natural human–machine interaction than synchronous BCIs, but it is a great challenge to train and adapt a self-paced BCI online because the user’s control intention and timing are usually unknown. This paper proposes a novel motor imagery based self-paced BCI paradigm for controlling a simulated robot in a specifically designed environment which is able to provide user’s control intention and timing during online experiments, so that online training and adaptation of the motor imagery based self-paced BCI can be effectively investigated. We demonstrate the usefulness of the proposed paradigm with an extended Kalman filter based method to adapt the BCI classifier parameters, with experimental results of online self-paced BCI training with four subjects.
TL;DR: Based on the positive results for poststroke rehabilitation, and in light of the motor problems in CP, motor imagery training may be a valuable additional tool for rehabilitation in CP.
Abstract: Converging evidence indicates that motor deficits in cerebral palsy (CP) are related not only to problems with execution, but also to impaired motor planning. Current rehabilitation mainly focuses on alleviating compromised motor execution. Motor imagery is a promising method of training the more 'cognitive' aspects of motor behaviour, and may, therefore, be effective in facilitating motor planning in patients with CP. In this review first we present the specific motor planning problems in CP followed by a discussion of motor imagery and its use in clinical practice. Second, we present the steps to be taken before motor imagery can be used for rehabilitation of upper limb functioning in CP. Motor imagery training has been shown to be a useful addition to existing rehabilitation protocols for poststroke rehabilitation. No such study has been conducted in CP. The age at which children can reliably use motor imagery, as well as the specific way in which motor imagery training needs to be implemented, must be researched before motor imagery training can be employed in children with CP. Based on the positive results for poststroke rehabilitation, and in light of the motor problems in CP, motor imagery training may be a valuable additional tool for rehabilitation in CP.
TL;DR: The proposed BCI provides a new practical multidimensional method by noninvasive EEG signal associated with human natural behavior, which does not need long-term training.
Abstract: This study aims to explore whether human intentions to move or cease to move right and left hands can be decoded from spatiotemporal features in non-invasive EEG in order to control a discrete two-dimensional cursor movement for a potential multidimensional brain-computer interface (BCI). Five naive subjects performed either sustaining or stopping a motor task with time locking to a predefined time window by using motor execution with physical movement or motor imagery. Spatial filtering, temporal filtering, feature selection and classification methods were explored. The performance of the proposed BCI was evaluated by both offline classification and online two-dimensional cursor control. Event-related desynchronization (ERD) and post-movement event-related synchronization (ERS) were observed on the contralateral hemisphere to the hand moved for both motor execution and motor imagery. Feature analysis showed that EEG beta band activity in the contralateral hemisphere over the motor cortex provided the best detection of either sustained or ceased movement of the right or left hand. The offline classification of four motor tasks (sustain or cease to move right or left hand) provided 10-fold cross-validation accuracy as high as 88% for motor execution and 73% for motor imagery. The subjects participating in experiments with physical movement were able to complete the online game with motor execution at an average accuracy of 85.5 +/- 4.65%; the subjects participating in motor imagery study also completed the game successfully. The proposed BCI provides a new practical multidimensional method by noninvasive EEG signal associated with human natural behavior, which does not need long-term training.
TL;DR: A critical review of motor imagery research conducted with children with focus on its merits and possible shortcomings in studying action representation with Included in the review are age-related findings, possible brain structures involved, experimental paradigms, and recommendations for future work.
TL;DR: In this article, the authors used repetitive transcranial magnetic stimulation to induce virtual lesions of either the superior parietal lobule (SPL) or the supramarginalis gyrus (SMG) in subjects performing a hand drawing rotation or a visual imagery task.
Abstract: Because motor imagery (MI) and visual imagery (VI) are influenced differently by factors such as biomechanical constraints or stimulus size, it is conceivable that they rely on separate processes, possibly involving distinct cortical networks, a view corroborated by neuroimaging and neuropsychological studies. In the posterior parietal cortex, it has been suggested that the superior parietal lobule (SPL) underlies VI, whereas MI relies on the supramarginalis gyrus (SMG). However, because several brain imaging studies have also shown an overlap of activations in SPL and SMG during VI or MI, the question arises as to which extent these 2 subregions really contribute to distinct imagery processes. To address this issue, we used repetitive transcranial magnetic stimulation to induce virtual lesions of either SMG or SPL in subjects performing a MI (hand drawing rotation) or a VI (letter rotation) task. Whatever hemisphere was stimulated, SMG lesions selectively altered MI, whereas SPL lesions only affected VI, demonstrating a double dissociation between MI and VI. Because these deficits were not influenced by the angular distance of the stimuli, we suggest that SMG and SPL are involved in the reenactment of the motor and visual representations, respectively, and not in mental rotation processes per se.
TL;DR: Motor imagery significantly improves central aspects of hand function, namely movement preparation time, while other modalities of handfunction appear to be unaffected.
TL;DR: According to the results, the children with DCD of the present study did rely on motor imagery to solve the mental rotation task; however, their judgments seem to be compromised by a less well-defined internal model.
Abstract: This study investigated the notion that children with developmental coordination disorder (DCD) show a reduced capacity of internally simulating movements of their own body or motor imagery. Using a mental rotation paradigm the contribution of hand posture to laterality/mirror judgments of bodily and alphanumeric stimuli was studied in 13 children with DCD and 13 matched typically developing (TD) children. Children were asked to judge whether the stimulus on display, rotated over -90 degrees , -30 degrees , +30 degrees , or +90 degrees , was a right or left hand or a canonical or mirror-reversed letter. Analysis of accuracy (ACC) and response times (RTs) demonstrated that children with DCD were generally slower and made more errors. RTs to letter stimuli were faster than those to hand stimuli in both DCD and TD children. For both groups RTs profiles were influenced by the orientation of the stimulus, showing longer response times for larger rotations. Clockwise rotations of right hands resulted in slower judgments than did counterclockwise rotations, whereas the reverse was true for left hands. Moreover, the results also indicate a contribution of hand posture to the laterality judgments of hands, with longer RTs when the posture of the participants' hands was opposite to the posture of the hands on display. Importantly, these effects that suggest an imagery strategy engaging motor processes were present in both groups. Apparently, the children with DCD of the present study did rely on motor imagery to solve the mental rotation task; however, their judgments seem to be compromised by a less well-defined internal model.
TL;DR: Evidence is provided that sleep contributes to the consolidation of motor sequence learning acquired through MI and offline delayed gains are not related to the MI content per se, and it is strongly confirmed that performance enhancement following MI is sleep dependent.
Abstract: THERE IS NOW COMPELLING EVIDENCE THAT SLEEP CONTRIBUTES TO THE CONSOLIDATION PROCESS OF PROCEDURAL TYPES OF MEMORY,1–3 AND OF MOTOR-sequence learning in particular4–9 The term memory consolidation refers to a poorly defined set of processes that convert an initial unstable memory representation into a more stable and effective form10 More specifically, Stickgold and Walker10 also proposed that this term should refer to the automatic postencoding processing occurring without intent or awareness but not to those requiring conscious and behavioral rehearsal Practically, researchers have reported the existence of delayed gains in performance using a sequential finger-tapping task after a night of sleep but not after a comparable time interval during daytime6,11–13 These findings support the role of sleep in the offline processing or reprocessing of memories,10 and some authors have even suggested that physical practice (PP) should ideally be followed by sleep to ensure long-lasting storage of a newly acquired motor skill5,8,14–16
By contrast, research investigating the possibility of sleep-related improvements in motor learning following mental practice with motor imagery (MI) has been almost nonexistent (see1, for an exception) Motor imagery is a dynamic state during which one mentally simulates an action without any concomitant body movement16 Studies looking at this learning-enhancing technique have shown that MI and PP of motor tasks show several parallel outcome characteristics, as shown by their degree of similarity at the temporal, behavioral, and neural levels18–22 Findings from these experiments have provided evidence that the time course of mentally simulated actions is correlated with that taken to execute the same movement Second, the analysis of the autonomic nervous system activity shows similar responses during imagined and actual movements Finally, brain-mapping techniques have shown that goal-directed actions, whether executed or imagined, recruit similar (albeit nonidentical) neural substrates Practically, MI has been found to be effective in the rehabilitation of patients with neurologic disorders affecting the motor system23–25 In an attempt to explore whether mental practice with MI can also elicit consolidation processes similar to those observed following PP, we have recently tested young healthy subjects who were required to imagine that they were performing a kinematic motor-adaptation task before and after a night of sleep1 Interestingly, practice with MI produced a significant increase in the subjects' speed to complete the target-reaching task following sleep, suggesting that this physiologic state plays a role in the consolidation of newly learned adapted movements Our interpretation of such findings was limited, however, by the fact that we could not exclude the possibility that performance gains were also partially due to the speed at which movements were performed during the MI condition Indeed, all participants strongly underestimated the time needed to reach each target, ie, they imagined doing the task faster than when they were physically performing the movements Such a lack of temporal congruence between the actual and imagined movements is known to result in a significant decrease in movement time26–27 Changing MI speed (voluntarily or not) is sufficient to elicit changes in the timing of actual movements, and it was therefore difficult to determine the influence of such effect, as compared with the contribution of sleep, to explain performance gains Second, our previous study did not include any group that was trained and retested during the daytime, and, thus, it was not possible to determine whether the gain in performance following MI was sleep dependent or was also due to the simple passage of time
The present study thus aimed to test further the hypothesis that mental practice of a motor sequence learning task with MI can elicit a consolidation process similar to that observed following PP of the same task To do so, we used an adapted version of the sequential finger-tapping task first developed by Karni et al28 This task was chosen because it is known that consolidation of this type of motor skill is sleep dependent,4,6,8 and because there is evidence of a temporal congruence between the physical and imagined conditions29 Indeed, investigators have previously shown that the time necessary to imagine a sequence of finger movements does not differ from that needed to physically produce the same sequential movements29 and that MI is effective in improving the performance on this type of motor skill30 In the present study, motor performance was evaluated before training, as well as before and after a night of sleep, or after a similar time interval without sleep during the daytime Groups of young healthy participants were either asked to PP or to imagine an explicitly known motor sequence Subjects in the MI condition were required to perform the sequence in real time (rtMI) or at a faster pace than usual (fMI) to control for possible effects of different mental representations on motor memory consolidation Specifically, comparing 2 MI-speed conditions was a prerequisite to identify whether voluntary changes in MI speed play a specific and critical role in explaining performance gains Last, a final NoSleep (control) group, in which subjects were trained and retested the same day (without any intervening sleep) after rtMI practice, was also included to test for the role of passage of time in consolidating this form of learning We predicted that all groups would demonstrate a significant improvement in performance following the initial training session Subjects in the PP, rtMI, and fMI conditions were also expected to show delayed gains in performance, whereas those in the NoSleep group were not Finally, based on findings from our previous study,1 we hypothesized that greater offline delayed gains would be observed in the fMI group, compared with the rtMI group
13 Nov 2009
TL;DR: It was shown that the ratio between the averaged value and the standard deviation over trials (S/N ratio) of Oxy-hemoglobin signal elicited by the imagery of subject's right hand was increased by the 5-day online feedback training.
Abstract: A brain-computer interface (BCI) to detect motor imagery from cerebrum hemodynamic data measured by NIRS (near-infrared spectroscopy) was constructed and the effect of the online feedback training for subjects was evaluated. Concentrations of Oxy- and deOxy-hemoglobin in the motor cortex during motor imagery of subject's right hand was measured by 52-channel NIRS system, and the mean magnitude of measured signal near C3 in the International 10–20 System was visually fed back online to the subject. On two out of three subjects, it was shown that the ratio between the averaged value and the standard deviation over trials (S/N ratio) of Oxy-hemoglobin signal elicited by the imagery of subject's right hand was increased by the 5-day online feedback training. Detailed investigation of the effect of the online feedback training on brain activities was left for further study.
TL;DR: The papers in this special issue are based on a selection of the best presentations at the 2007 meeting of the Computational Cognitive Neuroscience (CCN) conference, and are grouped according to three themes: Vision and visual working memory; High-level memory systems; and Reward and decision making.
TL;DR: It is suggested that maturation of parietal and prefrontal cortices during development may contribute to improvement of action representation in children and young adults.
Abstract: The present study investigated the effects of age and arm preference on motor imagery ability Children (groups: 65, 83, and 101 years) and young adults (224 years) physically or mentally performed a drawing motor task with the right or the left arm Imagery ability, accessed by the timing correspondence between executed and imagined movements, was poor at 6 and 8 years but improved at age 10, and was robust in adults The arm condition had no influence on imagery ability We suggest that maturation of parietal and prefrontal cortices during development may contribute to improvement of action representation