Positive Technology Journal

Mapping implied body actions in the human motor system.

J Neurosci. 2006 Jul 26;26(30):7942-9

Authors: Urgesi C, Moro V, Candidi M, Aglioti SM

The human visual system is highly tuned to perceive actual motion as well as to extrapolate dynamic information from static pictures of objects or creatures captured in the middle of motion. Processing of implied motion activates higher-order visual areas that are also involved in processing biological motion. Imagery and observation of actual movements performed by others engenders selective activation of motor and premotor areas that are part of a mirror-neuron system matching action observation and execution. By using single-pulse transcranial magnetic stimulation, we found that the mere observation of static snapshots of hands suggesting a pincer grip action induced an increase in corticospinal excitability as compared with observation of resting, relaxed hands, or hands suggesting a completed action. This facilitatory effect was specific for the muscle that would be activated during actual execution of the observed action. We found no changes in responsiveness of the tested muscles during observation of nonbiological entities with (e.g., waterfalls) or without (e.g., icefalls) implied motion. Thus, extrapolation of motion information concerning human actions induced a selective activation of the motor system. This indicates that overlapping motor regions are engaged in the visual analysis of physical and implied body actions. The absence of motor evoked potential modulation during observation of end posture stimuli may indicate that the observation-execution matching system is preferentially activated by implied, ongoing but not yet completed actions.

Motor imagery of walking following training in locomotor attention. The effect of 'the tango lesson'

Neuroimage. 2006 Jul 20;

Authors: Sacco K, Cauda F, Cerliani L, Mate D, Duca S, Geminiani GC

The hypothesis of this study is that focusing attention on walking motor schemes could modify sensorimotor activation of the brain. Indeed, gait is a learned automated process, mostly regulated by subcortical and spinal structures. We examined the functional changes in the activity of the cerebral areas involved in locomotor imagery tasks, before and after one week of training consisting of physical and mental practice. The aim of the training was to focus the subject's conscious attention on the movements involved in walking. In our training, subjects were asked to perform basic tango steps, which require specific ways of walking; each tango lesson ended with motor imagery training of the performed steps. The results show that training determines an expansion of active bilateral motor areas during locomotor imagery. This finding, together with a reduction of visuospatial activation in the posterior right brain, suggests a decreased role of visual imagery processes in the post-training period in favor of motor-kinesthetic ones.

Stroke. 2006 Jun 1;

Authors: Sharma N, Pomeroy VM, Baron JC

BACKGROUND AND PURPOSE: Understanding brain plasticity after stroke is important in developing rehabilitation strategies. Active movement therapies show considerable promise but depend on motor performance, excluding many otherwise eligible patients. Motor imagery is widely used in sport to improve performance, which raises the possibility of applying it both as a rehabilitation method and to access the motor network independently of recovery. Specifically, whether the primary motor cortex (M1), considered a prime target of poststroke rehabilitation, is involved in motor imagery is unresolved. Summary of Review--We review methodological considerations when applying motor imagery to healthy subjects and in patients with stroke, which may disrupt the motor imagery network. We then review firstly the motor imagery training literature focusing on upper-limb recovery, and secondly the functional imaging literature in healthy subjects and in patients with stroke. CONCLUSIONS: The review highlights the difficulty in addressing cognitive screening and compliance in motor imagery studies, particularly with regards to patients with stroke. Despite this, the literature suggests the encouraging effect of motor imagery training on motor recovery after stroke. Based on the available literature in healthy volunteers, robust activation of the nonprimary motor structures, but only weak and inconsistent activation of M1, occurs during motor imagery. In patients with stroke, the cortical activation patterns are essentially unexplored as is the underlying mechanism of motor imagery training. Provided appropriate methodology is implemented, motor imagery may provide a valuable tool to access the motor network and improve outcome after stroke.

Motor imagery.

J Physiol Paris. 2006 May 19.

Authors: Lotze M, Halsband U

We describe general concepts about motor imagery and differences to motor execution. The problem of controlling what the subject actually does during imagery is emphasized. A major part of the chapter is dealing with mental training by imagery and the usage of motor imagination in athletes, musicians and during rehabilitation. Data of altered representations of the body after loss of afferent information and motor representation due to limb amputation or complete spinal cord injury are demonstrated and discussed. Finally we provide an outlook on additional work about motor imagery important for further understanding of the topic.

Lateralization of unimanual and bimanual motor imagery.

Brain Res. 2006 May 18;

Authors: Stinear CM, Fleming MK, Byblow WD

Most studies of motor imagery have examined motor cortex function during imagery of dominant hand movement. The aim of this study was to examine the modulation of excitability in the dominant and non-dominant corticomotor pathways during kinesthetic motor imagery of unimanual and bimanual movement. Transcranial magnetic stimulation (TMS) was applied over the contralateral motor cortex (M1) to elicit motor-evoked potentials (MEPs) in the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles of each hand, in two separate sessions. Transcutaneous electrical stimuli were also delivered to the median nerve at each wrist, to elicit F-waves from APB. Fifteen right-handed volunteers imagined unimanual and bimanual phasic thumb movements, paced with a 1-Hz auditory metronome. Stimuli were delivered at rest, and either 50 ms before (ON phase), or 450 ms after (OFF phase), the metronome beeps. Significant MEP amplitude facilitation occurred only in right APB, during the ON phase of motor imagery of the right hand and both hands. Significant temporal modulation of right APB MEP amplitude was observed during motor imagery of right, left and bimanual performance. F-wave persistence and amplitude were unaffected by imagery. These results demonstrate that the motor imagery is lateralized to the left (dominant) hemisphere, which is engaged by imagery of each hand separately, and bimanual imagery. This finding has implications for the use of motor imagery in rehabilitation.

Neural substrates for motor imagery in severe hemiparesis.

Neurorehabil Neural Repair. 2006 Jun;20(2):268-77

Authors: Kimberley TJ, Khandekar G, Skraba LL, Spencer JA, Van Gorp EA, Walker SR

BACKGROUND: . The beneficial effects of imagined movements on motor learning and performance suggest that motor imagery is functionally close to preparatory and executive motor processes. OBJECTIVE: . The purpose of this study was to examine the cortical processes associated with imagery of movement of the wrist in subjects with severe hemiparesis. METHODS: . During fMRI, subjects with stroke performed alternating blocks of imagining wrist-tracking movements with the hemiparetic hand, active wrist-tracking movements with the unaffected hand, and resting. Control subjects performed the same tasks using an assigned hand. Cortical activation in the primary motor (M1), primary sensory (S1), supplementary motor area (SMA), and pre-SMA regions was determined through a laterality index of active voxels and signal intensity. Ability to imagine was assessed with an Imagery Rating Scale. RESULTS: .All subjects displayed primarily contralateral control during the track condition. Healthy subjects demonstrated contralateral control in all areas during the imagine condition, whereas subjects with stroke displayed primarily contralateral activation in S1 but ipsilateral in M1 and SMA. The percentage change in signal intensity was greater in the ipsilateral hemisphere in subjects with stroke than in the ipsilateral hemisphere in healthy subjects during the imagine condition. Additionally, subjects with self-reported low ability to imagine displayed no difference in activation compared to those with high imagery ability. CONCLUSIONS: . These findings are consistent with other works demonstrating primarily ipsilateral control of the hemiparetic hand in subjects with functional movement and lay the groundwork for further investigation into the ability of mental imagery to affect functionally relevant cortical control in subjects recovering from stroke.

Is there "feedback" during visual imagery? Evidence from a specificity of practice paradigm.

Can J Exp Psychol. 2006 Mar;60(1):24-32

Authors: Krigolson O, Van Gyn G, Tremblay L, Heath M

Motor-evoked potentials following imagery and limb disuse.

Int J Neurosci. 2006 May;116(5):639-51

Authors: Crews RT, Kamen G

Functions of the Mirror Neuron System: Implications for Neurorehabilitation.

Cogn Behav Neurol. 2006 Mar;19(1):55-63

Authors: Buccino G, Solodkin A, Small SL

Mirror neurons discharge during the execution of hand object-directed actions and during the observation of the same actions performed by other individuals. These neurons were first identified in the ventral premotor cortex (area F5) and later on in the inferior parietal lobule of monkey brain, thus constituting the mirror neuron system. More recently, mirror neurons for mouth object-directed actions have also been found in the monkey. Several pieces of experimental data demonstrate that a mirror neuron system devoted to hand, mouth, and foot actions is also present in humans. In the present paper we review the experimental evidence on the role of the mirror neuron system in action understanding, imitation learning of novel complex actions, and internal rehearsal (motor imagery) of actions. On the basis of features of the mirror neuron system and its role in action understanding and imitation, we discuss the possible use of action observation and imitation as an approach for systematic training in the rehabilitation of patients with motor impairment of the upper limb after stroke.

Cognitive skills analysis, kinesiology, and mental imagery in the acquisition of surgical skills.

J Otolaryngol. 2005 Oct;34(5):328-32

Authors: Bathalon S, Dorion D, Darveau S, Martin M

GOAL: Isolate and evaluate the impact of mental imagery on the acquisition of an emergency surgical technique. METHOD: We studied 44 first-year medical students performing a cricothyrotomy on a mannequin to determine the impact of teaching using mental imagery (MI) and/or kinesiology (KG) compared to the standard Advandec Trauma Life Support (ATLS) approach. Students were randomly assigned to one of three groups: MI and KG, KG alone or control (ATLS). Two weeks after the one-hour teaching session, they were evaluated with an OSCE testing the performance of the different steps of the technique, the time required and its fluidity. RESULTS: Total results (maximum: 25 marks) are as follows: KG + MI = 20.3 +/- 1.5 ; KG = 19.3 +/- 2.9 ; ATLS = 18.2 +/- 2.5. The only statistically significant difference for total results was in the use of MI and KG compared to the control group. Kinesiology alone or with mental imagery improved the fluidity of the performance. CONCLUSION: Many factors influence the acquisition of a surgical technique. This study showed that acquisition and performance of an emergency procedure (cricothyrotomy) was improved when mental imagery and kinesiology were combined to teach it.

The power of simulation: Imagining one's own and other's behavior 

Brain Res. 2006 Feb 3

Decety J, Grezes J.

A large number of cognitive neuroscience studies point to the similarities in the neural circuits activated during the generation, imagination, as well as observation of one's own and other's behavior. Such findings support the shared representations account of social cognition, which is suggested to provide the basic mechanism for social interaction. Mental simulation may also be a representational tool to understand the self and others. However, successfully navigating these shared representations - both within oneself and between individuals - constitutes an essential functional property of any autonomous agent. It will be argued that self-awareness and agency, mediated by the temporoparietal (TPJ) area and the prefrontal cortex, are critical aspects of the social mind. Thus, differences as well as similarities between self-- and other representations at the neural level may be related to the degrees of self-awareness and agency. Overall, these data support the view that social cognition draws on both domain-general mechanisms and domain-specific embodied representations.

Unilateral cerebellar stroke disrupts movement preparation and motor imagery.

Clin Neurophysiol. 2006 Mar 2;

Authors: Battaglia F, Quartarone A, Ghilardi MF, Dattola R, Bagnato S, Rizzo V, Morgante L, Girlanda P

OBJECTIVE: To assess motor cortex excitability, motor preparation and imagery in patients with unilateral cerebellar stroke with damage of the dentate nucleus by using transcranial magnetic stimulation (TMS). METHOD: Eight patients with unilateral cerebellar lesions due to tromboembolic stroke and 10 age matched healthy subjects were enrolled. Resting (RMT) and active (AMT) motor threshold, cortical and peripheral silent period, evaluation of motor imagery, reaction time and premovement facilitation of motor evoked potential (MEP) were tested bilaterally using TMS. RESULTS: The RMT and AMT were found to be increased contra lateral to the affected cerebellar hemisphere while the cortical silent period was prolonged. In addition the amount of MEP facilitation during motor imagery and the pre-movement facilitation were reduced in the motor cortex contra lateral to the affected cerebellar hemisphere. The reaction time, performed with the symptomatic hand, was slower. CONCLUSIONS: On the whole, our data confirm a role for the cerebellum in maintaining the excitability of primary motor area. Furthermore, patients with unilateral cerebellar stroke exhibit lateralized deficit of motor preparation and motor imagery. SIGNIFICANCE: Our results add to evidence that cerebellum contributes to specific aspects of motor preparation and motor imagery.

From the latest article in Science News Online:

New research suggests that physical exercise encourages healthy brains to function at their optimum levels. Fitness prompts nerve cells to multiply, strengthens their connections, and protects them from harm. Benefits seem to extend to brains and nerves that are diseased or damaged. These findings could suggest new treatments for people with Alzheimer's disease, Parkinson's disease, and spinal cord injuries.
[...]
Preliminary studies indicated that when lab animals exercise, their nerve cells release chemicals called neurotrophic factors. These proteins buffer nerve cells against illness or injury, prompt them to grow and multiply, and strengthen each neuron's connection with other nerve cells.
[...]
Furthermore, memory tests given to 1,740 people over 65 during a 6-year project have linked moderate exercise to reduced risk of dementia. These results were published in the Jan. 17 Annals of Internal Medicine by a Seattle research team.

From the news release 

New research at the University of Illinois at Urbana-Champaign shows that training re-ignites key areas of the brain, offsetting some age-related declines and boosting performance. The findings, involving functional magnetic resonance imaging (fMRI), provide the first visible evidence for a relationship between behavioral performance and cortical processors involved in dual-task processing, said Arthur F. Kramer, a professor of psychology and researcher at the Beckman Institute for Advanced Science and Technology.

The study, published online this month in advance of regular publication by the journal Neurobiology of Aginng, also adds to other emerging data that refute the idea that opposite brain areas become activated to help aging people compensate for a loss of cognition. Older studies, Kramer said, did not look at the impacts of training. For the new study, researchers in Kramer's lab looked at areas of the brain known to be associated with executive control - scheduling, planning, juggling multiple tasks and working memory. These areas, the ventral and dorsal prefrontal cortexes, are tied to cognitive declines in aging.

Read full article here 

Working memory and acquisition of implicit knowledge by imagery training, without actual task performance

Neuroscience. 2006 Jan 27;

Authors: Helene AF, Xavier GF

This study investigated acquisition of a mirror-reading skill via imagery training, without the actual performance of a mirror-reading task. In experiment I, healthy volunteers simulated writing on an imaginary, transparent screen placed at eye level, which could be read by an experimenter facing the subject. Performance of this irrelevant motor task required the subject to imagine the letters inverted, as if seen in a mirror from their own point of view (imagery training). A second group performed the same imagery training interspersed with a complex, secondary spelling and counting task. A third, control, group simply wrote the words as they would normally appear from their own point of view. After training with 300 words, all subjects were tested in a mirror-reading task using 60 non-words, constructed according to acceptable letter combinations of the Portuguese language. Compared with control subjects, those exposed to imagery training, including those who switched between imagery and the complex task, exhibited shorter reading times in the mirror-reading task. Experiment II employed a 2x3 design, including two training conditions (imagery and actual mirror-reading) and three competing task conditions (a spelling and counting switching task, a visual working memory concurrent task, and no concurrent task). Training sessions were interspersed with mirror-reading testing sessions for non-words, allowing evaluation of the mirror-reading acquisition process during training. The subjects exposed to imagery training acquired the mirror-reading skill as quickly as those exposed to the actual mirror-reading task. Further, performance of concurrent tasks together with actual mirror-reading training severely disrupted mirror-reading skill acquisition; this interference effect was not seen in subjects exposed to imagery training and performance of the switching and the concurrent tasks. These results unequivocally show that acquisition of implicit skills by top-down imagery training is at least as efficient as bottom-up acquisition.

Brain. 2005 Dec 19;

Authors: Kühn AA, Doyle L, Pogosyan A, Yarrow K, Kupsch A, Schneider GH, Hariz MI, Trottenberg T, Brown P

Activation of the basal ganglia has been shown during the preparation and execution of movement. However, the extent to which the activation during movement is related to efferent processes or feedback-related motor control remains unclear. We used motor imagery (MI), which eliminates peripheral feedback, to further investigate the role of the subthalamic area in the feedforward organization of movement. We recorded local field potential (LPF) activity from the region of the subthalamic nucleus (STN) in eight patients with Parkinson's disease off dopaminergic medication during performance of a warned reaction time task. Patients were instructed to either extend the wrist [motor execution (ME)], to imagine performing the same task without any overt movement (MI), or, in a subgroup, to perform a non-motor visual imagery (VI) task. MI led to event-related desynchronization (ERD) of oscillatory beta activity in the region of the STN in all patients that was similar in frequency, time course and degree to the ERD occurring during ME. The degree of ERD during MI correlated with the ERD in trials of ME and, like ME, was accompanied by a decrease in cortico-STN coherence, so that STN LFP activity during MI was similar to that in ME. The ERD in ME and MI were both significantly larger than the ERD in VI. In contrast, event-related synchronization (ERS) was significantly smaller in trials of MI, and even smaller in trials of VI, than during ME. The data suggest that the activity in the region of the human STN indexed by the ERD during movement is related to the feedforward organization of movement and is relatively independent of peripheral feedback. In contrast, sensorimotor feedback is an important factor in the ERS occurring in the STN area after completion of movement, consistent with a role for this region in trial-to-trial motor learning or the re-establishment of postural set following movements.

Percept Mot Skills. 2005 Aug;101(1):203-11

Authors: Brouziyne M, Molinaro C

Recent research on motor skills of golf have pointed to the usefulness of mental imagery. In golf, such training is rarely used as a teaching technique for beginners on the grounds that only top professionals stand to gain from mental imagery. This study tested whether mental imagery combined with physical practice can improve golf performance for the approach shot. 23 volunteer beginners, 8 women and 15 men, M age 23.4 yr. (SD = 3.7), enrolled in the University Physical and Sporting Activities Department, were divided into three groups, using a combination of physical practice of the approach shot plus mental imagery, physical practice only, and a third group engaging in various sporting activities instead of either mental or physical practice of the chip shot. Analysis showed that the beginners' approach shot performance improved most in the group combining physical practice and mental imagery when compared with the group just physically practising the approach shot. It seems mental training can be used effectively to improve performance even with beginners.

Neuroscience. 2005 Dec 7;

Authors: Gentili R, Papaxanthis C, Pozzo T

This study compares the improvement and generalization of arm motor performance after physical or mental training in a motor task requiring a speed-accuracy tradeoff. During the pre- and post-training sessions, 40 subjects pointed with their right arm as accurately and as fast as possible toward targets placed in the frontal plane. Arm movements were performed in two different workspaces called right and left paths. During the training sessions, which included only the right path, subjects were divided into four training groups (n=10): (i) the physical group, subjects overtly performed the task; (ii) the mental group, subjects imagined themselves performing the task; (iii) the active control group, subjects performed eye movements through the targets, (iv) the passive control group, subjects did not receive any specific training. We recorded movement duration, peak acceleration and electromyographic signals from arm muscles. Our findings showed that after both physical and mental training on the right path (training path), hand movement duration and peak acceleration respectively decreased and increased for this path. However, motor performance improvement was greater after physical compared with mental practice. Interestingly, we also observed a partial learning generalization, namely an enhancement of motor performance for the left path (non-training path). The amount of this generalization was roughly similar for the physical and mental groups. Furthermore, while arm muscle activity progressively increased during the training period for the physical group, the activity of the same muscles for the mental group was unchanged and comparable with that of the rest condition. Control groups did not exhibit any improvement. These findings put forward the idea that mental training facilitates motor learning and allows its partial transfer to nearby workspaces. They further suggest that motor prediction, a common process during both actual and imagined movements, is a fundamental operation for both sensorimotor control and learning.

Behav Brain Res. 2005 Nov 25

Authors: Fourkas AD, Ionta S, Aglioti SM