Showing papers on "Motor imagery published in 2008"
TL;DR: This work argues that gestures emerge from perceptual and motor simulations that underlie embodied language and mental imagery, and proposes the gestures-as-simulated-action framework to explain how gestures might arise from an embodied cognitive system.
Abstract: Spontaneous gestures that accompany speech are related to both verbal and spatial processes We argue that gestures emerge from perceptual and motor simulations that underlie embodied language and mental imagery We first review current thinking about embodied cognition, embodied language, and embodied mental imagery We then provide evidence that gestures stem from spatial representations and mental images We then propose the gestures-as-simulated-action framework to explain how gestures might arise from an embodied cognitive system Finally, we compare this framework with other current models of gesture production, and we briefly outline predictions that derive from the framework
699 citations
TL;DR: Although brain activity during movement execution and imagery was largely shared in the distributed motor network, imagery- related activity was in general more closely related to instruction-related activity than to the motor execution-relatedactivity.
Abstract: Activation of motor-related areas has consistently been found during various motor imagery tasks and is regarded as the central mechanism generating motor imagery. However, the extent to which motor execution and imagery share neural substrates remains controversial. We examined brain activity during preparation for and execution of physical or mental finger tapping. During a functional magnetic resonance imaging at 3 T, 13 healthy volunteers performed an instructed delay finger-tapping task either in a physical mode or mental mode. Number stimuli instructed subjects about a finger-tapping sequence. After an instructed delay period, cue stimuli prompted them either to execute the tapping movement or to imagine it. Two types of planning/preparatory activity common for movement and imagery were found: instruction stimulus-related activity represented widely in multiple motor-related areas and delay period activity in the medial frontal areas. Although brain activity during movement execution and imagery was largely shared in the distributed motor network, imagery-related activity was in general more closely related to instruction-related activity than to the motor execution-related activity. Specifically, activity in the medial superior frontal gyrus, anterior cingulate cortex, precentral sulcus, supramarginal gyrus, fusiform gyrus, and posterolateral cerebellum likely reflects willed generation of virtual motor commands and analysis of virtual sensory signals.
441 citations
TL;DR: In this paper, the authors review the models of greatest conceptual viability, and aim at describing the fields in which MI may play a crucial role, by integrating these functions in a unique model within motor performance and recovery.
Abstract: While there is ample evidence that motor imagery (MI) may improve motor performance, the models that have been proposed are mainly focused on some of the key components required to ascertain effectiveness, but do not give an extended overview of MI functions. This article reviews the models of greatest conceptual viability, and aims at describing the fields in which MI may play a crucial role, by integrating these functions in a unique model within motor performance and recovery. The detailed description of the imagery-based interventions considers distinct outcomes: (i) motor learning and performance, (ii) motivation, self-confidence and anxiety, (iii) strategies and problem-solving, and (iv) injury rehabilitation. The Motor Imagery Integrative Model of Imagery in Sport (MIIMS) may be used as a global guiding framework in the field of MI studies to develop more effective imagery interventions by covering the major key components of MI training related to the outcome achieved by athletes.
282 citations
TL;DR: FMRI results demonstrate that compared to skilled imagers, poor imagers not only need to recruit the cortico-striatal system, but to compensate with the cortICO-cerebellar system during MI of sequential movements.
277 citations
TL;DR: Current evidence suggests that Motor imagery provides additional benefits to conventional physiotherapy or occupational therapy, however, larger and methodologically sounder studies should be conducted to assess the benefits of Motor imagery.
Abstract: Evaluation of how Motor Imagery and conventional therapy (physiotherapy or occupational therapy) compare to conventional therapy only in their effects on clinically relevant outcomes during rehabilitation of persons with stroke. Systematic review of the literature We conducted an electronic database search in seven databases in August 2005 and also hand-searched the bibliographies of studies that we selected for the review. Two reviewers independently screened and selected all randomized controlled trials that compare the effects of conventional therapy plus Motor Imagery to those of only conventional therapy on stroke patients. The outcome measurements were: Fugl-Meyer Stroke Assessment upper extremity score (66 points) and Action Research Arm Test upper extremity score (57 points). Due to the high variability in the outcomes, we could not pool the data statistically. We identified four randomized controlled trials from Asia and North America. The quality of the included studies was poor to moderate. Two different Motor imagery techniques were used (three studies used audiotapes and one study had occupational therapists apply the intervention). Two studies found significant effects of Motor Imagery in the Fugl-Meyer Stroke Assessment: Differences between groups amounted to 11.0 (1.0 to 21.0) and 3.2 (-4 to 10.3) respectively and in the Action Research Arm Test 6.1 (-6.2 to 18.4) and 15.8 (0.5 to 31.0) respectively. One study did not find a significant effect in the Fugl-Meyer Stroke Assessment and Color trail Test (p = 0.28) but in the task-related outcomes (p > 0.001). Current evidence suggests that Motor imagery provides additional benefits to conventional physiotherapy or occupational therapy. However, larger and methodologically sounder studies should be conducted to assess the benefits of Motor imagery.
273 citations
TL;DR: The results clearly indicate that the lack of activation in M1 during motor imagery is caused by suppression from the SMA, highlighting the importance of the S MA 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.
243 citations
TL;DR: Spatial and temporal characteristics of gait are associated with distinct brain networks in older adults and addressing focal neuronal losses in these networks may represent an important strategy to prevent mobility disability.
Abstract: THERE is consistent evidence that older adults experiencing mobility impairment are more likely to have underlying impairment in the structure (1-10) and function (11-14) of the brain. Previous brain-imaging studies of older adults have shown that global brain atrophy and white matter hyperintensities (WMHs) within the connections that spread around the ventricles and under the frontal cortex are associated with clinical measures of poor balance and slow gait (2,4-7,15-17) and also with longer double support time (10). We have also shown that brain infarcts, mostly located in the basal ganglia (10), are associated with shorter steps. These previous imaging studies relied on semiquantitative estimates of diffuse brain structural changes rather than on quantitative measures of focal and region-specific abnormalities. The measures of overall brain volume and diffuse WMHs are not specific for mobility impairment, and they are associated with changes in several other functional domains besides mobility (e.g., with mood and cognition).
The objective of this study is to identify the spatial distribution of focal, region-specific neuronal loss in association with individual quantitative gait characteristics independently of other risk factors of gait abnormalities, including peripheral (peripheral neuropathy, obesity, or arthritis) and central (markers of diffuse brain structural abnormalities and cognitive function measures) risk factors. Aside from studies conducted in patient populations with overt neurological diseases, the spatial distribution of region-specific abnormalities associated with individual characteristics of gait has not been well explored in community-dwelling older adults. Our recent region-specific volumetric study suggested the presence of such spatial distribution for crude measures of mobility, such as gait speed and difficulty holding the semitandem stand (18), but it did not examine the relationship with distinct, quantitative measures of spatial and temporal gait characteristics.
In this study, we measure the association between the gray matter volume of individual brain regions and spatial (step width, step length) and temporal (double support time, stance time, step time) characteristics of gait. We hypothesize that wider steps, which are related to balance control (19), are associated with smaller volumes of regions important for balance regulation (basal ganglia and cerebellum). Based on evidence from previous studies (2,4-7,10,15-17), we hypothesize that longer steps are associated with smaller volumes in the basal ganglia and with regions connected to these via the cortico-striato-thalamic loops (primary motor and sensorimotor regions) and that double support time is associated with those regions that are connected through the periventricular cortico-thalamic connections (thalamus, primary motor, and sensorimotor regions). In secondary analyses, we examine the associations with regions important for visuospatial attention (inferior and superior posterior parietal lobules; 20), cognitive processing speed/executive control function (dorsolateral prefrontal cortex [dLPFC]), memory (hippocampus), and motor imagery (precuneus, posterior cingulated cortex, parahippocampus). Finally, we test the hypothesis that the association between brain regions and gait characteristics is partially explained by lower scores on the Digit Symbol Substitution Test (DSST), a test of visuospatial attention and cognitive processing speed. The rationale for this hypothesis is that lower scores on executive control function tests are associated with structural and functional abnormalities of these regions and also with gait.
203 citations
TL;DR: The role of cortical structures outside primary motor regions in imagining locomotion movements when accurate foot positioning and increased postural control is required is emphasized, and MI was sensitive to the constraints imposed by a narrow walking path.
199 citations
TL;DR: This work shows how subjects, after performing cue-based feedback training (smiley paradigm), learned to navigate self-paced through the freeSpace virtual environment (VE) and reported the results of three able-bodied subjects.
Abstract: The self-paced control paradigm enables users to operate brain-computer interfaces (BCI) in a more natural way: no longer is the machine in control of the timing and speed of communication, but rather the user is. This is important to enhance the usability, flexibility, and response time of a BCI. In this work, we show how subjects, after performing cue-based feedback training (smiley paradigm), learned to navigate self-paced through the ?freeSpace? virtual environment (VE). Similar to computer games, subjects had the task of picking up items by using the following navigation commands: rotate left, rotate right, and move forward ( three classes). Since the self-paced control paradigm allows subjects to make voluntary decisions on time, type, and duration of mental activity, no cues or routing directives were presented. The BCI was based only on three bipolar electroencephalogram channels and operated by motor imagery. Eye movements (electrooculogram) and electromyographic artifacts were reduced and detected online. The results of three able-bodied subjects are reported and problems emerging from self-paced control are discussed.
199 citations
TL;DR: The ERD/ERS preceding movement and motor imagery can be used to predict which of the four movements/imageries is about to occur, and to access this utility for brain-computer interface (BCI) applications.
197 citations
TL;DR: How motor imagery research has advanced knowledge of behavioral and neural aspects of action control, both in healthy subjects and clinical populations is reviewed and how motor imagery can provide new insights in a poorly understood psychopathological condition: conversion paralysis is illustrated.
TL;DR: The persistent functional coupling between these regions during task performance emphasizes the importance of sustained interactions between frontal and occipito-parietal areas during mental simulation of action.
Abstract: Several studies have revealed that posterior parietal and frontal regions support planning of hand movements but far less is known about how these cortical regions interact during the mental simulation of a movement. Here, we have used magnetoencephalography (MEG) to investigate oscillatory interactions between posterior and frontal areas during the performance of a well-established motor imagery task that evokes motor simulation: mental rotation of hands. Motor imagery induced sustained power suppression in the alpha and beta band over the precentral gyrus and a power increase in the gamma band over bilateral occipito-parietal cortex. During motor imagery of left hand movements, there was stronger alpha and beta band suppression over the right precentral gyrus. The duration of these power changes increased, on a trial-by-trial basis, as a function of the motoric complexity of the imagined actions. Crucially, during a specific period of the movement simulation, the power fluctuations of the frontal beta-band oscillations became coupled with the occipito-parietal gamma-band oscillations. Our results provide novel information about the oscillatory brain activity of posterior and frontal regions. The persistent functional coupling between these regions during task performance emphasizes the importance of sustained interactions between frontal and occipito-parietal areas during mental simulation of action.
TL;DR: The findings support the feasibility and justify the incorporation of home-based motor imagery exercises to improve walking skills for poststroke hemiparesis.
TL;DR: Findings suggest that motor planning centers of gait, including the SMA and PMd, are activated during both imagination (first-person perspective) and observation (third- person perspective) of gact behaviors.
TL;DR: The sensorimotor beta rhythm of EEG associated with human natural motor behavior can be used for a reliable and high performance BCI for both healthy subjects and patients with neurological disorders.
Abstract: To explore the reliability of a high performance brain–computer interface (BCI) using non-invasive EEG signals associated with human natural motor behavior does not require extensive training. We propose a new BCI method, where users perform either sustaining or stopping a motor task with time locking to a predefined time window. Nine healthy volunteers, one stroke survivor with right-sided hemiparesis and one patient with amyotrophic lateral sclerosis (ALS) participated in this study. Subjects did not receive BCI training before participating in this study. We investigated tasks of both physical movement and motor imagery. The surface Laplacian derivation was used for enhancing EEG spatial resolution. A model-free threshold setting method was used for the classification of motor intentions. The performance of the proposed BCI was validated by an online sequential binary-cursor-control game for two-dimensional cursor movement. Event-related desynchronization and synchronization were observed when subjects sustained or stopped either motor execution or motor imagery. Feature analysis showed that EEG beta band activity over sensorimotor area provided the largest discrimination. With simple model-free classification of beta band EEG activity from a single electrode (with surface Laplacian derivation), the online classifications of the EEG activity with motor execution/motor imagery were: >90%/∼80% for six healthy volunteers, >80%/∼80% for the stroke patient and ∼90%/∼80% for the ALS patient. The EEG activities of the other three healthy volunteers were not classifiable. The sensorimotor beta rhythm of EEG associated with human natural motor behavior can be used for a reliable and high performance BCI for both healthy subjects and patients with neurological disorders. Significance: The proposed new non-invasive BCI method highlights a practical BCI for clinical applications, where the user does not require extensive training. M This article features online multimedia enhancements (Some figures in this article are in colour only in the electronic version)
TL;DR: Neurophysiological and subjective data converge to suggest a key role of long-term experience in modulating sensorimotor body representations during mental simulation of sports.
Abstract: Specific physical or mental practice may induce short- and long-term neuroplastic changes in the motor system and cause tools to become part of one's own body representation. Athletes who use tools as part of their practice may be an excellent model for assessing the neural correlates of possible bodily representation changes that are specific to extensive practice. We used single-pulse transcranial magnetic stimulation to measure corticospinal excitability in forearm and hand muscles of expert tennis players and novices while they mentally practiced a tennis forehand, table tennis forehand, and a golf drive. The muscles of expert tennis players showed increased corticospinal facilitation during motor imagery of tennis but not golf or table tennis. Novices, although athletes, were not modulated across sports. Subjective reports indicated that only in the tennis imagery condition did experts differ from novices in the ability to form proprioceptive images and to consider the tool as an extension of the hand. Neurophysiological and subjective data converge to suggest a key role of long-term experience in modulating sensorimotor body representations during mental simulation of sports.
TL;DR: 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.
TL;DR: The differential effect of TMS(M1) when subjects performed a motor imagery task (relative to performing silent reading or frequency judgments with the same set of verbs) suggests that the primary motor cortex is critically involved in processing action verbs only when subjects are simulating the corresponding movement.
TL;DR: The role of BA 4 and its subdivisions may be non-executive, perhaps related to spatial encoding, though clearly further studies are needed as discussed by the authors, which may explain the differences between executed movement and motor imagery.
12 Aug 2008
TL;DR: An approach to image the cortical rhythmic modulation associated with motor imagery using minimum-norm estimates in the frequency domain (MNEFD) revealed that maximum correlation with movement imagination is localized in sensorimotor cortex.
Abstract: It is of wide interest to study the brain activity that correlates to the control of brain-computer interface (BCI). In the present study, we have developed an approach to image the cortical rhythmic modulation associated with motor imagery using minimum-norm estimates in the frequency domain (MNEFD). The distribution of cortical sources of mu activity during online control of BCI was obtained with the MNEFD. Contralateral decrease (event-related desynchronization) and ipsilateral increase (event-related synchronization) are localized in the sensorimotor cortex during online control of BCI in a group of human subjects. Statistical source analysis revealed that maximum correlation with movement imagination is localized in sensorimotor cortex.
TL;DR: The vividness of motor imagery poststroke remains similar to that of age-matched healthy persons and is not affected by the side of the lesion, however, after stroke motor imagery is not symmetrical and motor imagery vividness is better when imagining movements on the unaffected than on the affected side, indicating an overestimation possibly related to a hemispheric imbalance or a recalibration ofMotor imagery perception.
Abstract: Objective. The aim of this study was to investigate: (1) the effects of a stroke on motor imagery vividness as measured by the Kinesthetic and Visual Imagery Questionnaire (KVIQ-20); (2) the influence of the lesion side; and (3) the symmetry of motor imagery. Methods. Thirty-two persons who had sustained a stroke, in the right (n = 19) or left (n = 13) cerebral hemisphere, and 32 age-matched healthy persons participated. The KVIQ-20 assesses on a 5-point ordinal scale the clarity of the image (visual scale) and the intensity of the sensations (kinesthetic scale) that the subjects are able to imagine from the first-person perspective. Results. In both groups, the visual scores were higher (P = .0001) than the kinesthetic scores and there was no group difference. Likewise, visual scores remained higher than kinesthetic scores irrespective of the lesion side. The visual scores poststroke were higher (P = .001) when imagining upper limb movements on the unaffected side than those on the affected side. When fo...
TL;DR: This review describes and evaluates existing measures of motor imagery ability, and describes how explicit motor imageryAbility can be measured by questionnaire and mental chronometry, and how implicitMotor imagery ability can be measures through prospective action judgement and motorically driven perceptual decision paradigms.
Abstract: The internal nature of motor imagery makes the measurement of motor imagery ability a difficult task. In this review, we describe and evaluate existing measures of motor imagery ability. Following Jeannerod (1994, 1997) we define motor imagery in terms of imagined movement from the first person perspective. We describe how explicit motor imagery ability can be measured by questionnaire and mental chronometry, and how implicit motor imagery ability can be measured through prospective action judgement and motorically driven perceptual decision paradigms. Future research should be directed towards a theoretical analysis of motor imagery ability, the improvement of existing questionnaires and the development of new ones, and the standardisation of existing paradigms.
TL;DR: Brain imaging data corroborate the concept of action-related S-states because of the high overlap in core motor as well as in motor-related areas and argue that differential activity between S- states relates to task-specific and modal information processing.
Abstract: The simulation concept suggested by Jeannerod (Neuroimage 14:S103-S109, 2001) defines the S-states of action observation and mental simulation of action as action-related mental states lacking overt execution. Within this framework, similarities and neural overlap between S-states and overt execution are interpreted as providing the common basis for the motor representations implemented within the motor system. The present brain imaging study compared activation overlap and differential activation during mental simulation (motor imagery) with that while observing gymnastic movements. The fMRI conjunction analysis revealed overlapping activation for both S-states in primary motor cortex, premotor cortex, and the supplementary motor area as well as in the intraparietal sulcus, cerebellar hemispheres, and parts of the basal ganglia. A direct contrast between the motor imagery and observation conditions revealed stronger activation for imagery in the posterior insula and the anterior cingulate gyrus. The hippocampus, the superior parietal lobe, and the cerebellar areas were differentially activated in the observation condition. In general, these data corroborate the concept of action-related S-states because of the high overlap in core motor as well as in motor-related areas. We argue that differential activity between S-states relates to task-specific and modal information processing.
TL;DR: New results concerning timing and topographical distribution of the hemodynamic response during motor imagery measured by near-infrared spectroscopy are reported, which are known that motor imagery activates sensorimotor areas similar to those activated during execution of the same movement.
TL;DR: The study points to the profound reliance on phonatory and manual motor processing--a dual-route stratagem--used during music reading and further explores the phonatory nature of notational audiation with throat-audio and larynx-electromyography measurement.
Abstract: This study investigated the mental representation of music notation Notational audiation is the ability to internally "hear" the music one is reading before physically hearing it performed on an instrument In earlier studies, the authors claimed that this process engages music imagery contingent on subvocal silent singing This study refines the previously developed embedded melody task and further explores the phonatory nature of notational audiation with throat-audio and larynx-electromyography measurement Experiment 1 corroborates previous findings and confirms that notational audiation is a process engaging kinesthetic-like covert excitation of the vocal folds linked to phonatory resources Experiment 2 explores whether covert rehearsal with the mind's voice also involves actual motor processing systems and suggests that the mental representation of music notation cues manual motor imagery Experiment 3 verifies findings of both Experiments 1 and 2 with a sample of professional drummers The study points to the profound reliance on phonatory and manual motor processing--a dual-route stratagem--used during music reading Further implications concern the integration of auditory and motor imagery in the brain and cross-modal encoding of a unisensory input
TL;DR: The results suggest that rtfMRI helped individuals learn how to increase region-specific cortical activity associated with a motor imagery task, and the level of increased activation in motor areas was consolidated after the 2-week self-practice period, with the involvement of neural circuitries implicated in motor skill learning.
Abstract: We report the long-term effect of real-time functional MRI (rtfMRI) training on voluntary regulation of the level of activation from a hand motor area. During the performance of a motor imagery task of a right hand, blood-oxygenation-level-dependent (BOLD) signal originating from a primary motor area was presented back to the subject in real-time. Demographically-matched individuals also received the same procedure without valid feedback information. Followed by the initial rtfMRI sessions, both groups underwent 2-week long, daily-practice of the task. Off-line data analysis revealed that the individuals in the experimental group were able to increase the level of BOLD signal from the regulatory target to a greater degree compared with the control group. Furthermore, the learned level of activation was maintained after the 2-week period, with the recruitment of additional neural circuitries such as the hippocampus and the limbo-thalamo-cortical pathway. The activation obtained from the control group, in the absence of proper feedback, was indifferent across the training conditions. The level of BOLD activity from the target regulatory region was positively correlated with a self evaluative score within the experimental group, while the majority of control subjects had difficulty adopting a strategy to attain the desired level of functional regulation. Our results suggest that rtfMRI helped individuals learn how to increase region-specific cortical activity associated with a motor imagery task, and the level of increased activation in motor areas was consolidated after the 2-week self-practice period, with the involvement of neural circuitries implicated in motor skill learning. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 69–78, 2008
TL;DR: The findings imply that imagery training reduces the activity in parietal cortex suggesting that imagery is performed more automatic and results in a more efficient motor representation more easily accessed during motor performance.
Abstract: This study used functional magnetic resonance imaging (fMRI) to investigate differences in brain activity be- tween one group of active high jumpers and one group of high jumping novices (controls) when performing motor im- agery of a high jump. It was also investigated how internal imagery training affects neural activity. The results showed that active high jumpers primarily activated motor areas, e.g. pre-motor cortex and cerebellum. Novices activated visual areas, e.g. superior occipital cortex. Imagery training resulted in a reduction of activity in parietal cortex. These results in- dicate that in order to use an internal perspective during motor imagery of a complex skill, one must have well established motor representations of the skill which then translates into a motor/internal pattern of brain activity. If not, an external perspective will be used and the corresponding brain activation will be a visual/external pattern. Moreover, the findings imply that imagery training reduces the activity in parietal cortex suggesting that imagery is performed more automatic and results in a more efficient motor representation more easily accessed during motor performance.
TL;DR: Quasi-movements are introduced and it is shown that in healthy subjects quasi-movement can be effectively used in brain-computer interface research leading to a significantly smaller classification error in comparison to the errors obtained with conventionally used motor imagery strategies.
TL;DR: Findings from fMRI at 3T during imagined hand and foot movements are interpreted as evidence that BCI training as a conduit of motor imagery training may assist in maintaining access to SMC in largely preserved somatopy despite complete deafferentation.
Abstract: Although several features of brain motor function appear to be preserved even in chronic complete SCI, previous functional MRI (fMRI) studies have also identified significant derangements such as a strongly reduced volume of activation, a poor modulation of function and abnormal activation patterns. It might be speculated that extensive motor imagery training may serve to prevent such abnormalities. We here report on a unique patient with a complete traumatic SCI below C5 who learned to elicit electroencephalographic signals beta-bursts in the midline region upon imagination of foot movements. This enabled him to use a neuroprosthesis and to "walk from thought" in a virtual environment via a brain-computer interface (BCI). We here used fMRI at 3T during imagined hand and foot movements to investigate the effects of motor imagery via persistent BCI training over 8 years on brain motor function and compared these findings to a group of five untrained healthy age-matched volunteers during executed and imagined movements. We observed robust primary sensorimotor cortex (SMC) activity in expected somatotopy in the tetraplegic patient upon movement imagination while such activation was absent in healthy untrained controls. Sensorimotor network activation with motor imagery in the patient (including SMC contralateral to and the cerebellum ipsilateral to the imagined side of movement as well as supplementary motor areas) was very similar to the pattern observed with actual movement in the controls. We interpret our findings as evidence that BCI training as a conduit of motor imagery training may assist in maintaining access to SMC in largely preserved somatopy despite complete deafferentation.