Ok

By continuing your visit to this site, you accept the use of cookies. These ensure the smooth running of our services. Learn more.

Jul 08, 2007

Influence of mirror therapy on human motor cortex

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.

Jun 29, 2007

Cerebellar activity evoked by common tool-use execution and imagery tasks

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.

Cognitive tools for rehabilitation

Motor imagery and action observation: cognitive tools for rehabilitation.

J Neural Transm. 2007 Jun 20;

Authors: Mulder T

Rehabilitation, for a large part may be seen as a learning process where old skills have to be re-acquired and new ones have to be learned on the basis of practice. Active exercising creates a flow of sensory (afferent) information. It is known that motor recovery and motor learning have many aspects in common. Both are largely based on response-produced sensory information. In the present article it is asked whether active physical exercise is always necessary for creating this sensory flow. Numerous studies have indicated that motor imagery may result in the same plastic changes in the motor system as actual physical practice. Motor imagery is the mental execution of a movement without any overt movement or without any peripheral (muscle) activation. It has been shown that motor imagery leads to the activation of the same brain areas as actual movement. The present article discusses the role that motor imagery may play in neurological rehabilitation. Furthermore, it will be discussed to what extent the observation of a movement performed by another subject may play a similar role in learning. It is concluded that, although the clinical evidence is still meager, the use of motor imagery in neurological rehabilitation may be defended on theoretical grounds and on the basis of the results of experimental studies with healthy subjects.

May 07, 2007

Overt and imagined singing of an Italian aria

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.

May 02, 2007

Mirror therapy enhances lower-extremity motor recovery and motor functioning after stroke

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

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.

Jan 22, 2007

Motor imagery for pathologic pain

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.

Jan 21, 2007

Motor imagery and stroke rehabilitation

Motor imagery and stroke rehabilitation: a critical discussion.

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

Authors: de Vries S, Mulder T

Motor disorders are a frequent consequence of stroke and much effort is invested in the re-acquisition of motor control. Although patients often regain some of their lost function after therapy, most remain chronically disabled. Functional recovery is achieved largely through reorganization processes in the damaged brain. Neural reorganization depends on the information provided by sensorimotor efferent-afferent feedback loops. It has, however, been shown that the motor system can also be activated "offline" by imagining (motor imagery) or observing movements. The discovery of mirror neurones, which fire not only when an action is executed, but also when one observes another person performing the same action, also show that our action system can be used "online" as well as offline. It is an intriguing question as to whether the information provided by motor imagery or motor observation can lead to functional recovery and plastic changes in patients after stroke. This article reviews the evidence for motor imagery or observation as novel methods in stroke rehabilitation

The neural basis of narrative imagery

The neural basis of narrative imagery: emotion and action.

Prog Brain Res. 2006;156:93-103

Authors: Sabatinelli D, Lang PJ, Bradley MM, Flaisch T

It has been proposed that narrative emotional imagery activates an associative network of stimulus, semantic, and response (procedural) information. In previous research, predicted response components have been demonstrated through psychophysiological methods in peripheral nervous system. Here we investigate central nervous system concomitants of pleasant, neutral, and unpleasant narrative imagery with functional magnetic resonance imaging. Subjects were presented with brief narrative scripts over headphones, and then imagined themselves engaged in the described events. During script perception, auditory association cortex showed enhanced activation during affectively arousing (pleasant and unpleasant), relative to neutral imagery. Structures involved in language processing (left middle frontal gyrus) and spatial navigation (retrosplenium) were also active during script presentation. At the onset of narrative imagery, supplementary motor area, lateral cerebellum, and left inferior frontal gyrus were initiated, showing enhanced signal change during affectively arousing (pleasant and unpleasant), relative to neutral scripts. These data are consistent with a bioinformational model of emotion that considers response mobilization as the measurable output of narrative imagery.

Jan 15, 2007

Motor imagery of gait: a quantitative approach

Motor imagery of gait: a quantitative approach.

Exp Brain Res.
2007 Jan 9;

Authors: Bakker M, de Lange FP, Stevens JA, Toni I, Bloem BR

Motor imagery (MI) is widely used to study cognitive aspects of the neural control of action. Prior studies were mostly centred on hand and arm movements. Recently a few studies have used imagery tasks to explore the neurophysiology of human gait, but it remains unclear how to ascertain whether subjects actually perform imagery of gait as requested. Here we describe a new experimental protocol to quantify imagery of gait, by behaviourally distinguishing it from visual imagery (VI) processes and by showing its temporal correspondence with actual gait. Fourteen young healthy subjects performed two imagery tasks and an actual walking (AW) task. During both imagery tasks subjects were sitting on a chair and faced a computer screen that presented photographs of walking trajectories. During one task (MI), subjects had to imagine walking along the walking trajectory. During the other task (VI), subjects had to imagine seeing a disc moving along the walking trajectory. During the AW task, subjects had to physically walk along the same walking trajectory as presented on the photographs during the imagery tasks. We manipulated movement distance by changing the length of the walking trajectory, and movement difficulty by changing the width of the walking trajectory. Subjects reported onset and offset of both actual and imagined movements with a button press. The time between the two button presses was taken as the imagined or actual movement time (MT). MT increased with increasing path length and decreasing path width in all three tasks. Crucially, the effect of path width on MT was significantly stronger during MI and AW than during VI. The results demonstrate a high temporal correspondence between imagined and AW, suggesting that MI taps into similar cerebral resources as those used during actual gait. These results open the possibility of using this protocol for exploring neurophysiological correlates of gait control in humans.

Jan 06, 2007

Pushing the limits of imagination: mental practice for learning sequences

Pushing the limits of imagination: mental practice for learning sequences.

J Exp Psychol Learn Mem Cogn. 2007 Jan;33(1):254-61

Authors: Wohldmann EL, Healy AF, Bourne LE

In 2 experiments, the efficacy of motor imagery for learning to type number sequences was examined. Adults practiced typing 4-digit numbers. Then, during subsequent training, they either typed in the same or a different location, imagined typing, merely looked at each number, or performed an irrelevant task. Repetition priming (faster responses for old relative to new numbers) was observed on an immediate test and after a 3-month delay for participants who imagined typing. Improvement across the delay in typing old and new numbers was found for the imagined and actual typing conditions but not for the other conditions. The findings suggest that imagery can be used to acquire and retain representations of sequences and to improve general typing skill. ((c) 2007 APA, all rights reserved).

Dec 28, 2006

Intentional motor phantom limb syndrome

Intentional motor phantom limb syndrome.

Neurology. 2006 Dec 26;67(12):2140-6

Authors: Staub F, Bogousslavsky J, Maeder P, Maeder-Ingvar M, Fornari E, Ghika J, Vingerhoets F, Assal G

OBJECTIVE: To investigate the clinical and anatomic correlates of a previously unreported form of chronic supernumerary phantom limb, which developed only in association with motor intent directed at a hemiplegic-anesthetic upper limb. METHODS: We explored the phenomenology of the phantom illusion in the light of motor control models. Hemodynamic correlates of supernumerary phantom limb were studied with an fMRI sensorimotor paradigm consisting of finger-thumb opposition movements. RESULTS: The kinesthetic-proprioceptive illusion of a third arm was triggered by any attempt to move the paretic limb, by bimanual actions, and by motor imagery involving the nonfunctional limb. The responsible lesion destroyed the posterior part of the posterior limb of the internal capsule on the opposite side, damaging corticospinal and thalamocortical tracts. Comparison between fMRI signals performed during virtual movement of the phantom hand vs imaginary movement of the paretic hand showed increased activation in thalamus and caudate nucleus in the first condition. CONCLUSIONS: A preserved sense of agency provided by intact premotor processes translating intention into action may lead to the vivid feeling of movement in a paralyzed limb, similar to kinesthetic illusions in amputees. The interruption of thalamic afferences may explain the persistence and stability of the phantom by preventing any correction of the mismatch between expected and effective movement. The increased blood oxygen level-dependent (BOLD) signal in the basal ganglia-thalamus-cortex pathway during movement of the supernumerary hand may reflect an abnormal closed-loop functioning of the thalamocortical system underlying the phantom phenomenon.

Dec 20, 2006

Integration of motor imagery and physical practice in PD patients

Integration of motor imagery and physical practice in group treatment applied to subjects with Parkinson's disease.

Neurorehabil Neural Repair. 2007 Mar;21(1):68-75

Authors: Tamir R, Dickstein R, Huberman M

BACKGROUND: and PURPOSE: The application of motor imagery practice in the treatment of Parkinson's disease (PD) is a novel treatment approach for improving motor function. The purpose of this study was to compare group treatment using a combination of physical and motor imagery practice with group treatment using only physical practice in subjects with PD. METHODS: . Of 23 patients with idiopathic PD, 12 received combined therapy, whereas 11 received physical therapy alone. Exercises for both groups were applied during 1-h sessions held twice a week for 12 weeks. Comparable motor tasks provided to both groups included callisthenic exercises, functional tasks, and relaxation exercises. However, the experimental group was treated with both imagery and real practice, whereas the control group received only physical exercises. Outcome measures included the time required to complete sequences of movements, the performance of balance tasks, impairment and functional scores on the Unified Parkinson's Disease Rating Scale (UPDRS), and specific cognitive abilities (Stroop and clock drawing tests). RESULTS: . Following the intervention, the combined treatment group exhibited significantly faster performance of movement sequences than the control group. In addition, the experimental subjects demonstrated higher gains in the mental and motor subsets of the UPDRS and in the cognitive tests. Both groups improved on the activities of daily living scale. CONCLUSIONS: . The combination of motor imagery and real practice may be effective in the treatment of PD, especially for reducing bradykinesia. The implementation of this treatment regimen allows for the extension of practice time with negligible risk and low cost.

Nov 28, 2006

Motor imagery of complex everyday movements

Motor imagery of complex everyday movements. An fMRI study.

Neuroimage. 2006 Nov 15;

Authors: Szameitat AJ, Shen S, Sterr A

The present study aimed to investigate the functional neuroanatomical correlates of motor imagery (MI) of complex everyday movements (also called everyday tasks or functional tasks). 15 participants imagined two different types of everyday movements, movements confined to the upper extremities (UE; e.g., eating a meal) and movements involving the whole body (WB; e.g., swimming), during fMRI scanning. Results showed that both movement types activated the lateral and medial premotor cortices bilaterally, the left parietal cortex, and the right basal ganglia. Direct comparison of WB and UE movements further revealed a homuncular organization in the primary sensorimotor cortices (SMC), with UE movements represented in inferior parts of the SMC and WB movements in superior and medial parts. These results demonstrate that MI of everyday movements drives a cortical network comparable to the one described for more simple movements such as finger opposition. The findings further are in accordance with the suggestion that motor imagery-based mental practice is effective because it activates a comparable cortical network as overt training. Since most people are familiar with everyday movements and therefore a practice of the movement prior to scanning is not necessarily required, the current paradigm seems particularly appealing for clinical research and application focusing on patients with low or no residual motor abilities.

Nov 22, 2006

Motor imagery and EEG-based control of spelling devices and neuroprostheses

Motor imagery and EEG-based control of spelling devices and neuroprostheses.

Prog Brain Res. 2006;159:393-409

Authors: Neuper C, Müller-Putz GR, Scherer R, Pfurtscheller G

A brain-computer interface (BCI) transforms signals originating from the human brain into commands that can control devices or applications. With this, a BCI provides a new non-muscular communication channel, which can be used to assist patients who have highly compromised motor functions. The Graz-BCI uses motor imagery and associated oscillatory EEG signals from the sensorimotor cortex for device control. As a result of research in the past 15 years, the classification of ERD/ERS patterns in single EEG trials during motor execution and motor imagery forms the basis of this sensorimotor-rhythm controlled BCI. The major frequency bands of cortical oscillations considered here are the 8-13 and 15-30Hz bands. This chapter describes the basic methods used in Graz-BCI research and outlines possible clinical applications.

Motor imagery practice in gait rehabilitation of chronic post-stroke hemiparesis

Motor imagery practice in gait rehabilitation of chronic post-stroke hemiparesis: four case studies.

Int J Rehabil Res. 2006 Dec;29(4):351-356

Authors: Dunsky A, Dickstein R, Ariav C, Deutsch J, Marcovitz E

The aim of this series of pilot case studies was to examine the feasibility of enhancing the walking of individuals with post-stroke hemiparesis through the imagery practice of gait activities at home. Four persons with chronic hemiparesis received imagery gait practice, 3 days a week for 6 weeks. The intervention addressed gait impairments of the affected lower limb and task-specific gait training. Pre-intervention, mid-term, post-intervention and follow-up evaluations were performed. At 6 weeks from the beginning of treatment, the participants increased walking speed, stride length, cadence and single-support time on the affected lower limb, while decreasing double-support time. The findings appear to justify the institution of a larger-scale study in order to better delineate the contribution of motor imagery practice to gait performance in individuals with post-stroke hemiparesis.

Nov 05, 2006

A strategy for computer-assisted mental practice in stroke rehabilitation

A strategy for computer-assisted mental practice in stroke rehabilitation.

Neurorehabil Neural Repair. 2006 Dec;20(4):503-7

Authors: Gaggioli A, Meneghini A, Morganti F, Alcaniz M, Riva G

OBJECTIVE: To investigate the technical and clinical viability of using computer-facilitated mental practice in the rehabilitation of upper-limb hemiparesis following stroke. DESIGN: A single-case study. SETTING: Academic-affiliated rehabilitation center.Participant. A 46-year-old man with stable motor deficit of the upper right limb following subcortical ischemic stroke.Intervention. Three computer-enhanced mental practice sessions per week at the rehabilitation center, in addition to usual physical therapy. A custom-made virtual reality system equipped with arm-tracking sensors was used to guide mental practice. The system was designed to superimpose over the (unseen) paretic arm a virtual reconstruction of the movement registered from the nonparetic arm. The laboratory intervention was followed by a 1-month home-rehabilitation program, making use of a portable display device. MAIN OUTCOME MEASURES: Pretreatment and posttreatment clinical assessment measures were the upper-extremity scale of the Fugl-Meyer Assessment of Sensorimotor Impairment and the Action Research Arm Test. Performance of the affected arm was evaluated using the healthy arm as the control condition. RESULTS: The patient's paretic limb improved after the first phase of intervention, with modest increases after home rehabilitation, as indicated by functional assessment scores and sensors data. CONCLUSION: Results suggest that technology-supported mental training is a feasible and potentially effective approach for improving motor skills after stroke.

Oct 28, 2006

Recovery of hand function through mental practice: A study protocol.

Recovery of hand function through mental practice: A study protocol.

BMC Neurol. 2006 Oct 26;6(1):39

Authors: Ietswaart M, Johnston M, Dijkerman HC, Scott CL, Joice SA, Hamilton S, Macwalter RS

BACKGROUND: The study aims to assess the therapeutic benefits of motor imagery training in stroke patients with persistent motor weakness. There is evidence to suggest that mental rehearsal of movement can produce effects normally attributed to practising the actual movements. Imagining hand movements could stimulate the redistribution of brain activity, which accompanies recovery of hand function, thus resulting in a reduced motor deficit. Methods/ Design A multi-centre randomised controlled trial recruiting individuals between one and six months post-stroke ( n = 135). Patients are assessed before and after a four-week evaluation period. In this trial, 45 patients daily mentally rehearse movements with their affected arm under close supervision. Their recovery is compared to 45 patients who perform closely supervised non-motor mental rehearsal, and 45 patients who are not engaged in a training program. Motor imagery training effectiveness is evaluated using outcome measures of motor function, psychological processes, and level of disability. DISCUSSION: The idea of enhancing motor recovery through the use of motor imagery rehabilitation techniques is important with potential implications for clinical practice. The techniques evaluated as part of this randomised controlled trial are informed by the current understanding in cognitive neuroscience and the trial is both of scientific and applied interest. Trial Registration; Clinical Trial Registration; current clinical trial protocol registration NCT00355836.

Oct 11, 2006

EEG-based brain-computer interface

Electro-encephalogram based brain-computer interface: improved performance by mental practice and concentration skills.

Med Biol Eng Comput. 2006 Oct 7;

Authors: Mahmoudi B, Erfanian A

Mental imagination is the essential part of the most EEG-based communication systems. Thus, the quality of mental rehearsal, the degree of imagined effort, and mind controllability should have a major effect on the performance of electro-encephalogram (EEG) based brain-computer interface (BCI). It is now well established that mental practice using motor imagery improves motor skills. The effects of mental practice on motor skill learning are the result of practice on central motor programming. According to this view, it seems logical that mental practice should modify the neuronal activity in the primary sensorimotor areas and consequently change the performance of EEG-based BCI. For developing a practical BCI system, recognizing the resting state with eyes opened and the imagined voluntary movement is important. For this purpose, the mind should be able to focus on a single goal for a period of time, without deviation to another context. In this work, we are going to examine the role of mental practice and concentration skills on the EEG control during imaginative hand movements. The results show that the mental practice and concentration can generally improve the classification accuracy of the EEG patterns. It is found that mental training has a significant effect on the classification accuracy over the primary motor cortex and frontal area.

Oct 07, 2006

Song and speech

Song and speech: brain regions involved with perception and covert production.

Neuroimage. 2006 Jul 1;31(3):1327-42

Authors: Callan DE, Tsytsarev V, Hanakawa T, Callan AM, Katsuhara M, Fukuyama H, Turner R

This 3-T fMRI study investigates brain regions similarly and differentially involved with listening and covert production of singing relative to speech. Given the greater use of auditory-motor self-monitoring and imagery with respect to consonance in singing, brain regions involved with these processes are predicted to be differentially active for singing more than for speech. The stimuli consisted of six Japanese songs. A block design was employed in which the tasks for the subject were to listen passively to singing of the song lyrics, passively listen to speaking of the song lyrics, covertly sing the song lyrics visually presented, covertly speak the song lyrics visually presented, and to rest. The conjunction of passive listening and covert production tasks used in this study allow for general neural processes underlying both perception and production to be discerned that are not exclusively a result of stimulus induced auditory processing nor to low level articulatory motor control. Brain regions involved with both perception and production for singing as well as speech were found to include the left planum temporale/superior temporal parietal region, as well as left and right premotor cortex, lateral aspect of the VI lobule of posterior cerebellum, anterior superior temporal gyrus, and planum polare. Greater activity for the singing over the speech condition for both the listening and covert production tasks was found in the right planum temporale. Greater activity in brain regions involved with consonance, orbitofrontal cortex (listening task), subcallosal cingulate (covert production task) were also present for singing over speech. The results are consistent with the PT mediating representational transformation across auditory and motor domains in response to consonance for singing over that of speech. Hemispheric laterality was assessed by paired t tests between active voxels in the contrast of interest relative to the left-right flipped contrast of interest calculated from images normalized to the left-right reflected template. Consistent with some hypotheses regarding hemispheric specialization, a pattern of differential laterality for speech over singing (both covert production and listening tasks) occurs in the left temporal lobe, whereas, singing over speech (listening task only) occurs in right temporal lobe.