Positive Technology Journal

The suppressive influence of SMA on M1 in motor imagery revealed by fMRI and dynamic causal modeling.

Neuroimage. 2007 Dec 8;

Authors: Kasess CH, Windischberger C, Cunnington R, Lanzenberger R, Pezawas L, Moser E

Although motor imagery is widely used for motor learning in rehabilitation and sports training, the underlying mechanisms are still poorly understood. Based on fMRI data sets acquired with very high temporal resolution (300 ms) under motor execution and imagery conditions, we utilized Dynamic Causal Modeling (DCM) to determine effective connectivity measures between supplementary motor area (SMA) and primary motor cortex (M1). A set of 28 models was tested in a Bayesian framework and the by-far best-performing model revealed a strong suppressive influence of the motor imagery condition on the forward connection between SMA and M1. Our results clearly indicate that the lack of activation in M1 during motor imagery is caused by suppression from the SMA. These results highlight the importance of the SMA not only for the preparation and execution of intended movements, but also for suppressing movements that are represented in the motor system but not to be performed.

Centrally controlled heart rate changes during mental practice in immersive virtual environment: A case study with a tetraplegic.

Int J Psychophysiol. 2007 Nov 29;

Authors: Pfurtscheller G, Leeb R, Friedman D, Slater M

A tetraplegic patient was able to induce midcentral localized beta oscillations in the electroencephalogram (EEG) after extensive mental practice of foot motor imagery. This beta oscillation was used to simulate a wheel chair movement in a virtual environment (VE). The analysis of electrocardiogram (ECG) data revealed that the induced beta oscillations were accompanied by a characteristic heart rate (HR) change in form of a preparatory HR acceleration followed by a short-lasting deceleration in the order of 10-20 bpm (beats-per-minute). This provides evidence that mental practice of motor performance is accompanied not only by activation of cortical structures but also by central commands into the cardiovascular system with its nuclei in the brain stem.

Mental rotation of congenitally absent hands.

J Int Neuropsychol Soc. 2008 Jan;14(1):81-9

Authors: Funk M, Brugger P

The emergence of motor imagery in children.

J Exp Child Psychol. 2007 Nov 28;

Authors: Molina M, Tijus C, Jouen F

Quasi-movements: A novel motor-cognitive phenomenon.

Neuropsychologia. 2007 Oct 22;

Authors: Nikulin VV, Hohlefeld FU, Jacobs AM, Curio G

We introduce quasi-movements and define them as volitional movements which are minimized by the subject to such an extent that finally they become undetectable by objective measures. They are intended as overt movements, but the absence of the measurable motor responses and the subjective experience make quasi-movements similar to motor imagery. We used the amplitude dynamics of electroencephalographic alpha oscillations as a marker of the regional involvement of cortical areas in three experimental tasks: movement execution, kinesthetic motor imagery, and quasi-movements. All three conditions were associated with a significant suppression of alpha oscillations over the sensorimotor hand area of the contralateral hemisphere. This suppression was strongest for executed movements, and stronger for quasi-movements than for motor imagery. The topography of alpha suppression was similar in all three conditions. Proprioceptive sensations related to quasi-movements contribute to the assumption that the "sense of movement" can originate from central efferent processes. Quasi-movements are also congruent with the postulated continuity between motor imagery and movement preparation/execution. We also show that in healthy subjects quasi-movements can be effectively used in brain-computer interface research leading to a significantly smaller classification error ( approximately 47% of relative decrease) in comparison to the errors obtained with conventionally used motor imagery strategies.

High loads induce differences between actual and imagined movement duration.

Exp Brain Res. 2007 Nov 1;

Authors: Slifkin AB

Actual and imagined action may be governed by common information and neural processes. This hypothesis has found strong support from a range of chronometric studies showing that it takes the same amount of time to actually move and to imagine moving. However, exceptions have been observed when actual and imagined movements were made under conditions of inertial loading: sometimes the equivalency of actual and imagined movement durations (MDs) has been preserved, and other times it has been disrupted. The purpose of the current study was to test the hypothesis that the appearance and magnitude of actual-imagined MD differences in those studies was dependent on the level of load relative to the maximum loading capacity of the involved effector system [the maximum voluntary load (MVL)]. The experiment required 12 young, healthy humans to actually produce, and to imagine producing, single degree of freedom index finger movements under a range of loads (0, 5, 10, 20, 40, and 80% MVL). As predicted, statistically significant actual-imagined MD differences were absent at lower loads (0-20% MVL), but differences appeared and increased in magnitude with further increases in %MVL (40 and 80% MVL). That pattern of results may relate to the common, everyday experience individuals have in interacting with loads. Participants are likely to have extensive experience interacting with very low loads, but not high loads. It follows that the control of low inertial loads should be governed by complete central representations of action, while representations should be less complete for high loads. A consequence may be increases in the uncertainty of predicting motor output with increases in load. Compensation for the increased uncertainty may appear as increases in the MD values selected during both the preparation and imagery of action-according to a speed-uncertainty trade-off. Then, during actual action, MD may be reduced if movement-related feedback indicates that a faster movement would succeed.

Effects of movement imagery and electromyography-triggered feedback on arm hand function in stroke patients in the subacute phase.

Clin Rehabil. 2007 Jul;21(7):587-94

Authors: Hemmen B, Seelen HA

OBJECTIVE: To investigate the effects of movement imagery-assisted electromyography (EMG)-triggered feedback (focused on paretic wrist dorsiflexors) on the arm-hand function of stroke patients. DESIGN: Single-blinded, longitudinal, multicentre randomized controlled trial. Measurements were performed (on average) 54 days post stroke (baseline), three months later (post training) and at 12 months post baseline. SETTING: Two rehabilitation centres. SUBJECTS: Twenty-seven patients with a first-ever, ischaemic, subacute stroke. INTERVENTIONS: A reference group received conventional electrostimulation, while the experimental group received arm-hand function training based on EMG-triggered feedback combined with movement imagery. Both groups were trained for three months, 5 days/week, 30 minutes/day, in addition to their therapy as usual. MAIN MEASURES: Arm-hand function was evaluated using the upper extremity-related part of the Brunnstrom Fugl-Meyer test and the Action Research Arm test. RESULTS: During training, Brunnstrom Fugl-Meyer scores improved 8.7 points and Action Research Arm scores by 19.4 points (P < 0.0001) in both groups relative to baseline results, rising to 13.3 and 28.4 points respectively at one year follow-up (P < 0.0001). No between-group differences were found at any time. CONCLUSIONS: EMG-triggered feedback stimulation did not lead to more arm-hand function improvement relative to conventional electrostimulation. However, in contrast to many clinical reports, a significant improvement was still observed in both groups nine months after treatment ceased.

Movement imagery increases pain in people with neuropathic pain following complete thoracic spinal cord injury.

Pain. 2007 Oct 15;

Authors: Gustin SM, Wrigley PJ, Gandevia SC, Middleton JW, Henderson LA, Siddall PJ

Spinal cord injury (SCI) results in deafferentation and the onset of neuropathic pain in a substantial proportion of people. Based on evidence suggesting motor cortex activation results in attenuation of neuropathic pain, we sought to determine whether neuropathic SCI pain could be modified by imagined movements of the foot. Fifteen subjects with a complete thoracic SCI (7 with below-level neuropathic pain and 8 without pain) were instructed in the use of movement imagery. Movement imagery was practiced three times daily for 7days. On the eighth day, subjects performed the movement imagery in the laboratory and recorded pain ratings during the period of imagined movement. Six out of 7 subjects with neuropathic pain reported an increase in pain during imagined movements from 2.9+/-0.7 during baseline to 5.0+/-1.0 during movement imagery (p<0.01). In SCI subjects without neuropathic pain, movement imagery evoked an increase in non-painful sensation intensity from a baseline of 1.9+/-0.7 to 4.8+/-1.3 during the movement imagery (p<0.01). Two subjects without a history of pain or non-painful phantom sensations had onset of dysesthesia while performing imagined movements. This study reports exacerbation of pain in response to imagined movements and it contrasts with reports of reduction pain in people with peripheral neuropathic pain. The potential mechanisms underlying this sensory enhancement with movement imagery are discussed.

Preservation of motor programs in paraplegics as demonstrated by attempted and imagined foot movements.

Neuroimage. 2007 Aug 23;

Authors: Hotz-Boendermaker S, Funk M, Summers P, Brugger P, Hepp-Reymond MC, Curt A, Kollias SS

Execution and imagination of movement activate distinct neural circuits, partially overlapping in premotor and parietal areas, basal ganglia and cerebellum. Can long-term deafferented/deefferented patients still differentiate attempted from imagined movements? The attempted execution and motor imagery network of foot movements have been investigated in nine chronic complete spinal cord-injured (SCI) patients using fMRI. Thorough behavioral assessment showed that these patients were able to differentiate between attempted execution and motor imagery. Supporting the outcome of the behavioral assessment, fMRI disclosed specific patterns of activation for movement attempt and for motor imagery. Compared with motor execution data of healthy controls, movement attempt in SCI patients revealed reduced primary motor cortex activation at the group level, although activation was found in all single subjects with a high variability. Further comparisons with healthy subjects revealed that during attempt and motor imagery, SCI patients show enhanced activation and recruitment of additional regions in the parietal lobe and cerebellum that are important in sensorimotor integration. These findings reflect central plastic changes due to altered input and output and suggest that SCI patients may require additional cognitive resources to perform these tasks that may be one and the same phenomenon, or two versions of the same phenomenon, with quantitative differences between the two. Nevertheless, the retained integrity of movement attempt and motor imagery networks in SCI patients demonstrates that chronic paraplegics can still dispose of the full motor programs for foot movements and that therefore, attempted and imagined movements should be integrated in rehabilitative strategies.

Visuo-motor learning with combination of different rates of motor imagery and physical practice.

Exp Brain Res. 2007 Sep 12;

Authors: Allami N, Paulignan Y, Brovelli A, Boussaoud D

Sports psychology suggests that mental rehearsal facilitates physical practice in athletes and clinical rehabilitation attempts to use mental rehearsal to restore motor function in hemiplegic patients. Our aim was to examine whether mental rehearsal is equivalent to physical learning, and to determine the optimal proportions of real execution and rehearsal. Subjects were asked to grasp an object and insert it into an adapted slot. One group (G0) practiced the task only by physical execution (240 trials); three groups imagined performing the task in different rates of trials (25%, G25; 50%, G50; 75%, G75), and physically executed movements for the remaining trials; a fourth, control group imagined a visual rotation task in 75% of the trials and then performed the same motor task as the others groups. Movement time (MT) was compared for the first and last physical trials, together with other key trials, across groups. All groups learned, suggesting that mental rehearsal is equivalent to physical motor learning. More importantly, when subjects rehearsed the task for large numbers of trials (G50 and G75), the MT of the first executed trial was significantly shorter than the first executed trial in the physical group (G0), indicating that mental practice is better than no practice at all. Comparison of the first executed trial in G25, G50 and G75 with the corresponding trials in G0 (61, 121 and 181 trials), showed equivalence between mental and physical practice. At the end of training, the performance was much better with high rates of mental practice (G50/G75) compared to physical practice alone (G0), especially when the task was difficult. These findings confirm that mental rehearsal can be beneficial for motor learning and suggest that imagery might be used to supplement or partly replace physical practice in clinical rehabilitation.

Relationship between visual and motor imagery.

Percept Mot Skills. 2007 Jun;104(3 Pt 1):823-43

Authors: McAvinue LP, Robertson IH

The relationship between visual and motor imagery was investigated by administering a battery of visual and motor imagery measures to a sample of 101 men (n=49) and women (n=52), who ranged in age from 18 to 59 (M=34.5, SD= 12.6). A principal components analysis applied to the correlation matrix indicated four underlying components, which explained 62.9% of the variance. The components were named Implicit Visual Imagery Ability, Self-report of Visual and Motor Imagery, Implicit Motor Imagery Ability, and Explicit Motor Imagery Ability. These results suggested a dissociation between visual and motor imagery although visual and motor imagery were associated as self-reports and there were correlations among particular measures.

Internal and external imagery perspective measurement and use in imagining open and closed sports skills: an exploratory study.

Percept Mot Skills. 2007 Apr;104(2):387-404

Authors: Spittle M, Morris T

This study explored the measurement and use of internal and external imagery perspectives during imagery of open and closed sports skills. Participants (N=41; male=23; female=18), ages 14 to 28 (M = 19.4 yr.; SD = 3.1), who were recruited from undergraduate classes in human movement and physical education, and local sporting teams, completed the Imagery Use Questionnaire and then imagined performing eight common sports skills, four open skills and four closed skills, in a random order. Participants provided concurrent verbalisation during their imagery. Immediately after imagining each skill, participants completed a rating scale and retrospective verbalisation of imagery perspective use. Analysis indicated that the questionnaire gave a general imagery perspective preference but was not a strong predictor of imagery used on specific occasions. The three measures of imagery perspective were equivalent in imagining performing particular skills. Participants experienced more internal imagery than external imagery while imagining the eight sports skills, but there was no significant difference between perspective use on the open and closed skills.

Influence of mirror therapy on human motor cortex.

Int J Neurosci. 2007 Jul;117(7):1039-48

Authors: Fukumura K, Sugawara K, Tanabe S, Ushiba J, Tomita Y

This article investigates whether or not mirror therapy alters the neural mechanisms in human motor cortex. Six healthy volunteers participated. The study investigated the effects of three main factors of mirror therapy (observation of hand movements in a mirror, motor imagery of an assumed affected hand, and assistance in exercising the assumed affected hand) on excitability changes in the human motor cortex to clarify the contribution of each factor. The increase in motor-evoked potential (MEP) amplitudes during motor imagery tended to be larger with a mirror than without one. Moreover, MEP amplitudes increased greatly when movements were assisted. Watching the movement of one hand in a mirror makes it easier to move the other hand in the same way. Moreover, the increase in MEP amplitudes is related to the synergic effects of afferent information and motor imagery.

Cerebellar activity evoked by common tool-use execution and imagery tasks: an fMRI study.

Cortex. 2007 Apr;43(3):350-8

Authors: Higuchi S, Imamizu H, Kawato M

The purpose of this study is to identify the functional brain networks activated in relation to actual tool-use in humans. Although previous studies have identified brain activity related to tool-use gestures (Moll et al., 2000), they did not investigate the brain activity involved in such tool-use. We investigated brain activity using functional magnetic resonance imaging (fMRI) while human subjects mentally imagined using sixteen common tools and while they actually used them. Brain activity for both actual and imagined tool-use was found in the posterior part of the parietal cortex, in the supplementary motor area, and in the cerebellum. Under imagined tool-use conditions, we found brain activity in the premotor and right pars opercularis. Under actual tool-use conditions, we found it in the primary motor area, in the thalamus, and in the left pars opercularis. Our precise analysis in the cerebellum indicated that activity evoked by imagery was located significantly more lateral to that evoked by actual use. We found a relationship between activity in the tool imagery and execution conditions by comparing their t-value-weighted centroid of activation coordinates. Moreover, for half of the subjects the spatial distribution pattern for each tool was similar, suggesting that neural mechanisms contributing to skillful tool-use are modularly organized in the cerebellum.

Motor imagery and action observation: cognitive tools for rehabilitation.

J Neural Transm. 2007 Jun 20;

Authors: Mulder T

Overt and imagined singing of an Italian aria.

Neuroimage. 2007 Mar 24;

Authors: Kleber B, Birbaumer N, Veit R, Trevorrow T, Lotze M

Activation maps of 16 professional classical singers were evaluated during overt singing and imagined singing of an Italian aria utilizing a sparse sampling functional magnetic imaging (fMRI) technique. Overt singing involved bilateral primary and secondary sensorimotor and auditory cortices but also areas associated with speech and language production. Activation magnitude within the gyri of Heschl (A1) was comparable in both hemispheres. Subcortical motor areas (cerebellum, thalamus, medulla and basal ganglia) were active too. Areas associated with emotional processing showed slight (anterior cingulate cortex, anterior insula) activation. Cerebral activation sites during imagined singing were centered on fronto-parietal areas and involved primary and secondary sensorimotor areas in both hemispheres. Areas processing emotions showed intense activation (ACC and bilateral insula, hippocampus and anterior temporal poles, bilateral amygdala). Imagery showed no significant activation in A1. Overt minus imagined singing revealed increased activation in cortical (bilateral primary motor; M1) and subcortical (right cerebellar hemisphere, medulla) motor as well as in sensory areas (primary somatosensory cortex, bilateral A1). Imagined minus overt singing showed enhanced activity in the medial Brodmann's area 6, the ventrolateral and medial prefrontal cortex (PFC), the anterior cingulate cortex and the inferior parietal lobe. Additionally, Wernicke's area and Brocca's area and their homologues were increasingly active during imagery. We conclude that imagined and overt singing involves partly different brain systems in professional singers with more prefrontal and limbic activation and a larger network of higher order associative functions during imagery.

Mirror therapy enhances lower-extremity motor recovery and motor functioning after stroke: a randomized controlled trial.

Arch Phys Med Rehabil. 2007 May;88(5):555-9

Authors: Sütbeyaz S, Yavuzer G, Sezer N, Koseoglu BF

OBJECTIVE: To evaluate the effects of mirror therapy, using motor imagery training, on lower-extremity motor recovery and motor functioning of patients with subacute stroke. DESIGN: Randomized, controlled, assessor-blinded, 4-week trial, with follow-up at 6 months. SETTING: Rehabilitation education and research hospital. PARTICIPANTS: A total of 40 inpatients with stroke (mean age, 63.5y), all within 12 months poststroke and without volitional ankle dorsiflexion. INTERVENTIONS: Thirty minutes per day of the mirror therapy program, consisting of nonparetic ankle dorsiflexion movements or sham therapy, in addition to a conventional stroke rehabilitation program, 5 days a week, 2 to 5 hours a day, for 4 weeks. MAIN OUTCOME MEASURES: The Brunnstrom stages of motor recovery, spasticity assessed by the Modified Ashworth Scale (MAS), walking ability (Functional Ambulation Categories [FAC]), and motor functioning (motor items of the FIM instrument). RESULTS: The mean change score and 95% confidence interval (CI) of the Brunnstrom stages (mean, 1.7; 95% CI, 1.2-2.1; vs mean, 0.8; 95% CI, 0.5-1.2; P=.002), as well as the FIM motor score (mean, 21.4; 95% CI, 18.2-24.7; vs mean, 12.5; 95% CI, 9.6-14.8; P=.001) showed significantly more improvement at follow-up in the mirror group compared with the control group. Neither MAS (mean, 0.8; 95% CI, 0.4-1.2; vs mean, 0.3; 95% CI, 0.1-0.7; P=.102) nor FAC (mean, 1.7; 95% CI, 1.2-2.1; vs mean, 1.5; 95% CI, 1.1-1.9; P=.610) showed a significant difference between the groups. CONCLUSIONS: Mirror therapy combined with a conventional stroke rehabilitation program enhances lower-extremity motor recovery and motor functioning in subacute stroke patients.

Mental practice in chronic stroke: results of a randomized, placebo-controlled trial.

Stroke. 2007 Apr;38(4):1293-7

Authors: Page SJ, Levine P, Leonard A

BACKGROUND AND PURPOSE: Mental practice (MP) of a particular motor skill has repeatedly been shown to activate the same musculature and neural areas as physical practice of the skill. Pilot study results suggest that a rehabilitation program incorporating MP of valued motor skills in chronic stroke patients provides sufficient repetitive practice to increase affected arm use and function. This Phase 2 study compared efficacy of a rehabilitation program incorporating MP of specific arm movements to a placebo condition using randomized controlled methods and an appropriate sample size. Method- Thirty-two chronic stroke patients (mean=3.6 years) with moderate motor deficits received 30-minute therapy sessions occurring 2 days/week for 6 weeks, and emphasizing activities of daily living. Subjects randomly assigned to the experimental condition also received 30-minute MP sessions provided directly after therapy requiring daily MP of the activities of daily living; subjects assigned to the control group received the same amount of therapist interaction as the experimental group, and a sham intervention directly after therapy, consisting of relaxation. Outcomes were evaluated by a blinded rater using the Action Research Arm test and the upper extremity section of the Fugl-Meyer Assessment. RESULTS: No pre-existing group differences were found on any demographic variable or movement scale. Subjects receiving MP showed significant reductions in affected arm impairment and significant increases in daily arm function (both at the P<0.0001 level). Only patients in the group receiving MP exhibited new ability to perform valued activities. CONCLUSIONS: The results support the efficacy of programs incorporating mental practice for rehabilitating affected arm motor function in patients with chronic stroke. These changes are clinically significant.

Graded motor imagery for pathologic pain: a randomized controlled trial.

Neurology. 2006 Dec 26;67(12):2129-34

Authors: Moseley GL

BACKGROUND: Phantom limb and complex regional pain syndrome type 1 (CRPS1) are characterized by changes in cortical processing and organization, perceptual disturbances, and poor response to conventional treatments. Graded motor imagery is effective for a small subset of patients with CRPS1. OBJECTIVE: To investigate whether graded motor imagery would reduce pain and disability for a more general CRPS1 population and for people with phantom limb pain. METHODS: Fifty-one patients with phantom limb pain or CRPS1 were randomly allocated to motor imagery, consisting of 2 weeks each of limb laterality recognition, imagined movements, and mirror movements, or to physical therapy and ongoing medical care. RESULTS: There was a main statistical effect of treatment group, but not diagnostic group, on pain and function. The mean (95% CI) decrease in pain between pre- and post-treatment (100 mm visual analogue scale) was 23.4 mm (16.2 to 30.4 mm) for the motor imagery group and 10.5 mm (1.9 to 19.2 mm) for the control group. Improvement in function was similar and gains were maintained at 6-month follow-up. CONCLUSION: Motor imagery reduced pain and disability in these patients with complex regional pain syndrome type I or phantom limb pain, but the mechanism, or mechanisms, of the effect are not clear.

Motor imagery and stroke rehabilitation: a critical discussion.

J Rehabil Med. 2007 Jan;39(1):5-13

Authors: de Vries S, Mulder T