Motor imagery: perception or action?

Motor imagery and its implications for understanding the motor system

In the neurosciences, motor imagery (MIm) has not just been a topic of basic research. It has also attracted attention in applied research as a therapeutic tool. MIm is conceptualized as an internal simulation of motor acts that generates images on the basis of motor representations. Therefore, MIm is associated with neural activation of the cortical and subcortical motor system. The resulting concept of functional equivalence between MIm and execution opens a window to study the organization of motor processes and, more generally, to understand the neural plasticity of the motor system.

Imaging motor imagery: methodological issues related to expertise

Mental imagery (MI) is the mental rehearsal of movements without overt execution. Brain imaging techniques have made it possible to identify the brain regions that are activated during MI and, for voluntary motor tasks involving hand and finger movements, to make direct comparison with those areas activated during actual movement. However, the fact that brain activation differs for different types of imagery (visual or kinetic) and depends on the skill level of the individual (e.g., novice or elite athlete) raises a number of important methodological issues for the design of brain imaging protocols to study MI. These include instructing the subject concerning the type of imagery to use, objective measurement of skill level, the design of motor tasks sufficiently difficult to produce a range of skill levels, the effect of different environments on skill level (including the imaging device), and so on. It is suggested that MI is more about the neurobiology of the development of motor skills that have already been learned, but not perfected, than it is about learning motor skills de novo.

Motor representations and practice affect brain systems underlying imagery: an FMRI study of internal imagery in novices and active high jumpers

This study used functional magnetic resonance imaging (fMRI) to investigate differences in brain activity between one group of active high jumpers and one group of high jumping novices (controls) when performing motor imagery 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 indicate 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.

Movement and visual coding: the structure of visuo-spatial working memory

The influential model of verbal working memory (WM) introduced by Baddeley and Hitch (Recent advances in learning and motivation. Academic, New York, 1974) comprised three interacting component parts; an executive controller and two subservient systems. The two subservient systems, one underpinning verbal processing and the other underpinning visual processing are themselves subdivided. In the verbal system, a passive phonological store is maintained by an active phonological loop, which is able to rehearse the material in the passive store. The visual working memory system has traditionally been thought of as having a similar architecture with a passive visual store being maintained by an active store, which codes in terms of movement over space. The paper discusses the evidence for this relationship in visuo-spatial WM and concludes that the architecture does not fit well with the experimental literature. A direction for future research is suggested.

Motor imagery in physical therapist practice

Motor imagery is the mental representation of movement without any body movement. Abundant evidence on the positive effects of motor imagery practice on motor performance and learning in athletes, people who are healthy, and people with neurological conditions (eg, stroke, spinal cord injury, Parkinson disease) has been published. The purpose of this update is to synthesize the relevant literature about motor imagery in order to facilitate its integration into physical therapist practice. This update also will discuss visual and kinesthetic motor imagery, factors that modify motor imagery practice, the design of motor imagery protocols, and potential applications of motor imagery.

Adapting movement planning to motor impairments: The motor-scanning system

Previous studies have reported a similar duration for movement execution (real movement) and its internal simulation with motor imagery (virtual movement). The present work has studied the real movement-virtual movement relationship for complex sequences of finger movements after different acute and chronic brain lesions and after a long-lasting restriction of right-hand movements. Age, hand-movement restriction and lesions of pyramidal system, basal ganglia and cerebellum did not prevent the high real movement-virtual movement correlation. The data suggest that movement execution and its internal simulation share the same neuronal basis. However, the calculation of virtual delay (a useful procedure for detecting small real movement-virtual movement differences) showed significant real movement-virtual movement mismatches, suggesting the existence of a separate and selective system that, continuously scanning the competence of the different elements participating in motor behavior, adjusts the planning of future movements to the real capability of the motor system.

Recovery of hand function through mental practice: a study protocol

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.

The adjunctive role of imagery on the functional rehabilitation of a grade II ankle sprain

The purpose of the present study was to examine the effectiveness of imagery on muscular endurance, dynamic balance, and functional stability in athletes who sustained a grade II ankle sprain. The sample consisted of 20 active athletes (aged from 18 to 30 years) with a grade II ankle sprain, as confirmed by ultrasound testing. The participants were randomly divided into two groups of 10 participants each; one experimental and one control group. The experimental group received 12 individual sessions of imagery rehearsal in addition to a normal course of physical therapy, while the control group followed only the physical therapy treatment. Results revealed significant differences only in the variable of muscular endurance. This study partly supports the contribution of imagery to the functional rehabilitation of grade II ankle sprain. Further research should be conducted to examine the effect of imagery on the functional rehabilitation of sport injuries using other tests of functional rehabilitation along with larger sample sizes.

15 years of BCI research at Graz University of Technology: current projects

Over the last 15 years, the Graz Brain-Computer Interface (BCI) has been developed and all components such as feature extraction and classification, mode of operation, mental strategy, and type of feedback have been investigated. Recent projects deal with the development of asynchronous BCIs, the presentation of feedback and applications for communication and control.

Mental rotation in schizophrenia

Motor imagery provides a direct insight into action representations. The aim of the present study was to investigate the level of impairment of action monitoring in schizophrenia by evaluating the performance of schizophrenic patients on mental rotation tasks. We raised the following questions: (1) Are schizophrenic patients impaired in motor imagery both at the explicit and at the implicit level? (2) Are body parts more difficult for them to mentally rotate than objects? (3) Is there any link between the performance and the hallucinating symptom profile? The schizophrenic patients (n = 13) displayed the same pattern of performance as the control subjects (n = 13). More particularly, schizophrenic patients' reaction time varied as a function of the angular disparity of the stimuli. On the other hand, they were significantly slower and less accurate. Interestingly, patients suffering from hallucinations made significantly more errors than non-hallucinatory patients. We discussed these latter results in terms of deficit of the forward model. We emphasized the necessity to distinguish different levels of action, more or less impaired in schizophrenia.

The interval for interference in conscious visual imagery

Three experiments are described that use dynamic visual noise (DVN) to interfere with words processed under visual and verbal processing instructions. In Experiment 1 DVN is presented to coincide with the encoding of the words or to coincide with the interval between encoding and recall. The results show that while DVN is a robust disruptor when it is applied during encoding to words processed under visual instruction, it has no effect during encoding when the words are processed under rote instruction. Moreover, DVN has no effect when it is applied during the retention interval, no matter what means are employed to encode the words. Experiment 2 extends these findings by again showing no effect of DVN during the retention interval, yet showing robust interference effects for visually processed words during recall. Finally, Experiment 3 demonstrates that the results of Experiments 1 and 2 cannot be explained by a difference in the time duration associated with application of DVN during the retention interval compared to during encoding and recall. Moreover, the differing decay functions for visually and verbally processed words during the intervals used in Experiment 3 suggest that any failure to cause interference is not because the two processing instructions resulted in words being retained in the same medium. The functions are consistent with word storage mechanisms reflecting appropriately verbal and visual properties. The results are discussed in terms of current models of visual working memory. It is argued that a full interpretation of the results requires a buffer mechanism as an important component of any model of visual working memory.

Imagery of motor actions: Differential effects of kinesthetic and visual–motor mode of imagery in single-trial EEG

Single-trial motor imagery classification is an integral part of a number of brain-computer interface (BCI) systems. The possible significance of the kind of imagery, involving rather kinesthetic or visual representations of actions, was addressed using the following experimental conditions: kinesthetic motor imagery (MIK), visual-motor imagery (MIV), motor execution (ME) and observation of movement (OOM). Based on multi-channel EEG recordings in 14 right-handed participants, we applied a learning classifier, the distinction sensitive learning vector quantization (DSLVQ) to identify relevant features (i.e., frequency bands, electrode sites) for recognition of the respective mental states. For ME and OOM, the overall classification accuracies were about 80%. The rates obtained for MIK (67%) were better than the results of MIV (56%). Moreover, the focus of activity during kinesthetic imagery was found close to the sensorimotor hand area, whereas visual-motor imagery did not reveal a clear spatial pattern. Consequently, to improve motor-imagery-based BCI control, user training should emphasize kinesthetic experiences instead of visual representations of actions.

Corticospinal facilitation during first and third person imagery

Motor imagery can be defined as the covert rehearsal of movement. Previous research with transcranial magnetic stimulation (TMS) has demonstrated that motor imagery increases the corticospinal excitability of the primary motor cortex in the area corresponding to the representation of the muscle involved in the imagined movement. This research, however, has been limited to imagery of oneself in motion. We extend the TMS research by contrasting first person imagery and third person imagery of index finger abduction-adduction movements. Motor evoked potentials were recorded from first dorsal interosseous (FDI) and abductor digiti minimi (ADM) during single pulse TMS. Participants performed first and third person motor imagery, visual imagery, and static imagery. Visual imagery involved non biological motion while static imagery involved a first person perspective of the unmoving hand. Relative to static imagery, excitability during imagined movement increased in FDI but not ADM. The facilitation in first person imagery adds to previous findings. A greater facilitation of MEPs recorded from FDI was found in third person imagery where the action was clearly attributable to another person. We interpret this novel result in the context of observed action and imagined observation of self action, and attribute the result to activation of mirror systems for matching the imagined action with an inner visuo-motor template.

Interference effects demonstrate distinct roles for visual and motor imagery during the mental representation of human action

Four experiments were completed to characterize the utilization of visual imagery and motor imagery during the mental representation of human action. In Experiment 1, movement time functions for a motor imagery human locomotion task conformed to a speed-accuracy trade-off similar to Fitts' Law, whereas those for a visual imagery object motion task did not. However, modality-specific interference effects in Experiment 2 demonstrate visual and motor imagery as cooperative processes when the action represented is tied to visual coordinates in space. Biomechanic-specific motor interference effects found in Experiment 3 suggest one basis for separation of processing channels within motor imagery. Finally, in Experiment 4 representations of motor actions were found to be generated using only visual imagery under certain circumstances: namely, when the imaginer represented the motor action of another individual while placed at an opposing viewpoint. These results suggest that the modality of representation recruited to generate images of human action is dependent on the dynamic relationship between the individual, movement, and environment.

Motor imagery in hypnosis: accuracy and duration of motor imagery in waking and hypnotic states

This study assessed response times and accuracy of motor imagery in waking and hypnotic states and to related responses to hypnotic experiences. The Vividness of Motor Imagery Questionnaire (VMIQ) was administered to 47 participants. A mental walking task was then performed in the waking state. In hypnosis, the same task was included within an imaginary journey after a hypnotic induction. An interaction effect showed for condition (waking vs. hypnotic) and distances. The further the participants had to walk in imagination, the longer they took. For all combinations, participants took significantly longer in hypnosis (p < .001) and were significantly less accurate in hypnosis in reproducing the difference between the different distances (p < .001). Results appear to show a relationship between motor imagery and hypnotic responding and support a state-trait conception of imagery.

Disturbance of Motor Imagery After Cerebellar Stroke

The authors studied the possible involvement of the cerebellum in nonexecutive motor functions needed for a normal performance of complex motor patterns by analyzing (using chronometric evaluation) finger movement sequences and their respective motor imagery (a mental simulation of motor patterns). Patients suffering from a cerebellar stroke (n=11) were compared with aged-matched control volunteers (n=11). Patients that had apparently recovered from a unilateral cerebellar stroke showed a marked slowing of motor performance in both hands (ipsi- and contralateral to lesion). This effect was accompanied by a similar slowing of motor imagery, suggesting that the cerebellum, traditionally implicated in the control of motor execution, is also involved in nonexecutive motor functions such as the planning and internal simulation of movements.

Neural substrates of real and imagined sensorimotor coordination

Much debate in the behavioral literature focuses on the relative contribution of motor and perceptual processes in mediating coordinative stability. To a large degree, such debate has proceeded independently of what is going on in the brain. Here, using blood oxygen level-dependent measures of neural activation, we compare physically executed and imagined rhythmic coordination in order to better assess the relative contribution of hypothesized neuromusculoskeletal mechanisms in modulating behavioral stability. The executed tasks were to coordinate index finger to thumb opposition movements of the right hand with an auditory metronome in either a synchronized (on the beat) or syncopated (off the beat) pattern. Imagination involved the same tasks, except without physical movement. Thus, the sensory stimulus and coordination constraints were the same in both physical and imagination tasks, but the motoric requirements were not. Results showed that neural differences between executed synchronization and syncopation found in premotor cortex, supplementary motor area, basal ganglia and lateral cerebellum persist even when the coordinative patterns were only imagined. Neural indices reflecting behavioral stability were not abolished by the absence of overt movement suggesting that coordination phenomena are not exclusively rooted in purely motoric constraints. On the other hand, activity in the superior temporal gyrus was modulated by both the presence of movement and the nature of the coordination, attesting to the intimacy between perceptual and motoric processes in coordination dynamics.

Hand movement distribution in the motor cortex: the influence of a concurrent task and motor imagery

The aim of this work was to study the relevance of the primary motor cortex (M1) for motor functions different to the simple execution of motor orders. The M1 activity during the performance with individual fingers of a simple motor task (tonic flexion), a motor task that includes a complex motor computation but not motor execution (motor imagery), and a motor task that involves both the computation and execution of movements (phasic movement) was evaluated by functional magnetic resonance imaging (fMRI). The possible influence of other cortical tasks on the M1 activation induced by finger movements was assessed by evaluating the effect of a distracting concurrent task (numeric calculation). Data show that both the dimension of the area activated and the intensity of response were higher during motor planning than during motor execution. There is a mosaic-like distribution for motor-planning M1 functions, with the movement of individual fingers being controlled from several M1 loci. The concurrent mental-task induces a rapid functional reconfiguration of M1, adding M1 subsets to motor programming but excluding others. Present data support the involvement of the M1 in more than just simple motor execution, showing broader and more intense modifications during motor tasks not accompanied by movements (motor imagery) than during the execution of simple motor acts (tonic flexion).

Relation between sport and spatial imagery: comparison of three groups of participants

The literature suggests that sport may be considered a spatial activity and that engaging in spatial activities increases the capacity of an individual to implement mental imagery. Moreover, mental rotation calls upon motor processes that are heavily involved in sporting activities. For these reasons, the authors hypothesized that athletes ought to perform mental rotation tasks better than nonathletes. Also, athletes trained to react quickly to constantly changing environments should be faster at processing the information in a mental rotation task than athletes operating in more settled environments. The results of this study show that athletes performed the mental rotation task significantly faster than nonathletes. These results support the suggestion that there is a link between sport and the ability to perform mental image transformations; however, this ability may not be specific to the conditions in which the athlete performs.

Brain lateralization of motor imagery: motor planning asymmetry as a cause of movement lateralization

Movement asymmetry in humans and animals is often considered as being induced by the brain lateralization of the motor system. In the present work, the hemispheric asymmetry for motor planning as a cause of behavioral lateralization was examined. This study was carried out on normal volunteers and patients suffering unilateral brain damage caused by a stroke. Motor planning was evaluated by using the motor imagery of hand movement, a mental representation of a motor pattern that includes its internal simulation but not its real execution. The present study shows marked similarities between virtual movement executed during motor imagery and real movements. Thus, performance time showed a high correlation between real and virtual movements in the following conditions: (1) during dominant and non-dominant hand movements; (2) in simple and complex motor tasks; (3) in young control subjects; (4) in stroke patients; and (5) control subjects aged-matched to stroke patients. Brain strokes increased the performance time in both real and virtual movements. Left-brain strokes decreased the velocity of the real movements in both hands, whereas right-brain strokes mainly disturbed movements in the left hand. A similar effect was observed for virtual movements, suggesting a left-brain dominance for motor planning in humans. However, two-handed movement tasks suggest a complex interaction during motor planning, an interaction that facilitates motor performance during mirror movements and delays motor execution during non-mirror movements.

Training with Computer-Supported Motor Imagery in Post-Stroke Rehabilitation

Converging lines of evidence suggest that motor imagery (the mental simulation of a motor act within working memory) is associated with subliminal activation of the motor system. This observation has led to the hypothesis that cortical activation during motor imagery may affect the acquisition of specific motor skills and help the recovery of motor function. In this paper, we describe a clinical protocol in which we use interactive tools to stimulate motor imagery in hemiplegic stroke patients, thereby helping them to recover lost motor function. The protocol consists of an inpatient and an outpatient phase, combining physical and mental practice. In the inpatient phase, patients are trained in a laboratory setting, using a custom-made interactive workbench (VR Mirror). After discharge, patients use a portable device to guide mental and physical practice in a home setting. The proposed strategy is based on the hypotheses that: (a) combined physical and mental practice can make a cost-effective contribution to the rehabilitation of stroke patients, (b) effective mental practice is not possible without some form of support, from a therapist (as in our inpatient phase) or from technology (as in the outpatient phase), (c) the inclusion of an outpatient phase will allow the patient to practice more often than would otherwise be possible, therefore increasing the speed and/or effectiveness of learning, and (d) the use of interactive technology will reduce the patient's need for skilled support, therefore improving the cost-effectiveness of training.

Grundlagen und Empirie der Neuropsychologischen Therapie: Neuropsychotherapie oder Hirnjogging?

Zusammenfassung: Dieser Beitrag beschäftigt sich mit dem theoretischen Fundament und den empirischen Grundlagen neuropsychologischer Interventionen. Nach einem kurzen historischen Rückblick werden die konzeptionellen Grundlagen einer neuropsychologischen Behandlung dargestellt und erläutert. Neuropsychologische Interventionen werden drei Therapiesäulen zugeordnet: Restitution, Kompensation und integrierten Verfahren. Restitution bezieht sich auf Maßnahmen, mit denen gestörte neuronale Systeme wieder reaktiviert werden sollen. Kompensation beinhaltet den aktiven oder passiven Ausgleich von Funktionsdefiziten durch vorhandene Fähigkeiten. Hierzu zählt nicht nur das Lernen neuer Strategien und der Einsatz von Hilfsmitteln, sondern auch die Veränderung von Erwartungen, Lebenszielen und andere kognitive Anpassungen. Integrierte Verfahren stellen Verfahren (z. B. operante Techniken) anderer Psychotherapierichtungen dar, die bei einer neuropsychologischen Behandlung Anwendung finden können und auf die Bedürfnisse von Patienten mit organisch bedingten psychischen Störungen zugeschnitten sind. Die in dem Beitrag referierten Studien unterstreichen die Bedeutung der drei postulierten Therapiesäulen.

Imagery of Voluntary Movement of Fingers, Toes, and Tongue Activates Corresponding Body-Part-Specific Motor Representations

We investigate whether imagery of voluntary movements of different body parts activates somatotopical sections of the human motor cortices. We used functional magnetic resonance imaging to detect the cortical activity when 7 healthy subjects imagine performing repetitive (0.5-Hz) flexion/extension movements of the right fingers or right toes, or horizontal movements of the tongue. We also collected functional images when the subjects actually executed these movements and used these data to define somatotopical representations in the motor areas. In this study, we relate the functional activation maps to cytoarchitectural population maps of areas 4a, 4p, and 6 in the same standard anatomical space. The important novel findings are 1) that imagery of hand movements specifically activates the hand sections of the contralateral primary motor cortex (area 4a) and the contralateral dorsal premotor cortex (area 6) and a hand representation located in the caudal cingulate motor area and the most ventral part of the supplementary motor area; 2) that when imagining making foot movements, the foot zones of the posterior part of the contralateral supplementary motor area (area 6) and the contralateral primary motor cortex (area 4a) are active; and 3) that imagery of tongue movements activates the tongue region of the primary motor cortex and the premotor cortex bilaterally (areas 4a, 4p, and 6). These results demonstrate that imagery of action engages the somatotopically organized sections of the primary motor cortex in a systematic manner as well as activating some body-part-specific representations in the nonprimary motor areas. Thus the content of the mental motor image, in this case the body part, is reflected in the pattern of motor cortical activation.

Use of Mental Imagery to Limit Strength Loss after Immobilization

Objective:

To assess whether mental imagery of gripping prevents the loss of grip strength associated with forearm immobilization.

Design:

Pretest–posttest randomized-group design.

Setting:

Laboratory.

Participants:

13 female and 5 male university students, age between 17 and 30 years, randomly assigned into 2 groups—1 control and 1 experimental.

Interventions:

Both groups had their nondominant forearms immobilized for 10 days. The experimental group undertook three 5-min mental-imagery sessions daily, during which they imagined they were squeezing a rubber ball.

Main Outcome Measures:

Wrist-flexion and -extension and grip strength before and after immobilization.

Results:

There was no significant change in wrist-flexion or -extension strength in the mental-imagery group. The control group experienced a significant decrease in wrist-flexion and -extension strength during the period of immobilization (P< .05).

Conclusions:

Despite study limitations, the results suggest that mental imagery might be useful in preventing the strength loss associated with short-term muscle immobilization

Relation between sport activity and mental rotation: comparison of three groups of subjects

The aim was to observe the relation between sport activity and performance on a mental image-transformation task. A classical mental rotation task using abstract stimuli was administered to three groups: (a) gymnasts who used mental and physical rotations in their practice, (b) athletes whose activities required very little motor rotation, and (c) nonathletes. Both sport groups performed similarly and obtained significantly shorter response times than those of the nonathletes. We suggest that the regular practice of spatial activities, such as sports, could be related to the spatial capacities of the participants.

Chronometric comparisons of imagery to action: visualizing versus physically performing springboard dives

Motor imagery research emphasizes similarities between the mental imagery of an action and its physical execution. In this study, temporal differences between motor imagery and its physical performance as a function of performer expertise, skill complexity, and spatial ability were investigated. Physical execution times for springboard dives were compared with visualized execution times. Results indicate that physical and visualized performance times were not identical: Their relation is a function of dive complexity and diver expertise, but not their interaction. Relative to physical time, visualization time increased with increased complexity, suggesting the involvement of capacity-limited working memory. A nonmonotonic relation was found for expertise: Unlike experts or novices, visualization time for intermediates was significantly slower than physical time. These temporal differences are most consistent with schematic differences in skill representation. Intermediates may be relatively slowed by greater amounts of nonautomatized knowledge, as compared with the automatized knowledge of experts or the sparse knowledge of novices.

Predicting the effects of actions: interactions of perception and action

Many theories in cognitive psychology assume that perception and action systems are clearly separated from the cognitive system. Other theories suggest that important cognitive functions reside in the interactions between these systems. One consequence of the latter claim is that the action system may contribute to predicting the future consequences of currently perceived actions. In particular such predictions might be more accurate when one observes one's own actions than when one observes another person's actions, because in the former case the system that plans the action is the same system that contributes to predicting the action's effects. In the present study participants (N = 104) watched video clips displaying either themselves or somebody' else throwing a dart at a target board and predicted the dart's landing position. The predictions were more accurate when participants watched themselves acting. This result provides evidence for the claim that perceptual input can be linked with the action system to predict future outcomes of actions.

Mental object rotation and the planning of hand movements

Recently, we showed that the simultaneous execution of rotational hand movements interferes with mental object rotation, provided that the axes of rotation coincide in space. We hypothesized that mental object rotation and the programming of rotational hand movements share a common process presumably involved in action planning. Two experiments are reported here that show that the mere planning of a rotational hand movement is sufficient to cause interference with mental object rotation. Subjects had to plan different spatially directed hand movements that they were asked to execute only after they had solved a mental object rotation task. Experiment 1 showed that mental object rotation was slower if hand movements were planned in a direction opposite to the presumed mental rotation direction, but only if the axes of hand rotation and mental object rotation were parallel in space. Experiment 2 showed that this interference occurred independent of the preparatory hand movements observed in Experiment 1. Thus, it is the planning of hand movements and not their preparation or execution that interferes with mental object rotation. This finding underlines the idea that mental object rotation is an imagined (covert) action, rather than a pure visual-spatial imagery task, and that the interference between mental object rotation and rotational hand movements is an interference between goals of actions.

Integrating cognitive psychology, neurology and neuroimaging

In the last decade, there has been a dramatic increase in research effectively integrating cognitive psychology, functional neuroimaging, and behavioral neurology. This new work is typically conducting basic research into aspects of the human mind and brain. The present review features as examples of such integrations two series of studies by the author and his colleagues. One series, employing object recognition, mental motor imagery, and mental rotation paradigms, clarifies the nature of a cognitive process, imagined spatial transformations used in shape recognition. Among other implications, it suggests that when recognizing a hand's handedness, imagining one's body movement depends on cerebrally lateralized sensory-motor structures and deciding upon handedness depends on exact match shape confirmation. The other series, using cutaneous, tactile, and auditory pitch discrimination paradigms, elucidates the function of a brain structure, the cerebellum. It suggests that the cerebellum has non-motor sensory support functions upon which optimally fine sensory discriminations depend. In addition, six key issues for this integrative approach are reviewed. These include arguments for the value and greater use of: rigorous quantitative meta-analyses of neuroimaging studies; stereotactic coordinate-based data, as opposed to surface landmark-based data; standardized vocabularies capturing the elementary component operations of cognitive and behavioral tasks; functional hypotheses about brain areas that are consistent with underlying microcircuitry; an awareness that not all brain areas implicated by neuroimaging or neurology are necessarily directly involved in the associated cognitive or behavioral task; and systematic approaches to integrations of this kind.

Mindfulness of movement as a coping strategy in multiple sclerosis. A pilot study

This study investigated the effectiveness of a short course of mindfulness of movement to help with symptom management in eight people with multiple sclerosis. Progress was compared to a control group who were asked to continue with their current care. Each participant received six individual one-to-one sessions of instruction. They were also provided with audio and videotape aides. Each participant was assessed on a test of balance, pre- and post-intervention, and at 3-month follow-up. All participants completed a rating of change of 22 symptoms relevant to multiple sclerosis. A close relative or friend was also asked to assess independently the degree of change. The mindfulness group reported improvement over a broad range of symptoms. This was verified by the relatives' independent rating and maintained at 3 month follow-up. The control group showed no improvement but instead tended towards a deterioration on many of the items. The physical assessment of balance also showed a significant improvement for the mindfulness group. This improvement was maintained at 3 month follow-up. In conclusion, training in mindfulness of movement appeared to result in improved symptom management for this group of people with multiple sclerosis. This was a pilot study, using small numbers, so the results need to be treated with caution. Several improvements to the experimental design are suggested. The role of individual therapeutic ingredients is discussed.

Impairment of motor imagery in putamen lesions in humans

Patients with putamen or cortical lesions participated in a first- and third-person movement imagery task, each primarily engaging kinesthetic and visual imagery. The subjects were instructed to imagine themselves (first-person task) and a third party (third-person task) performing a sequence of three movements and to choose from a set of four photos the end posture resulting from the movements. The results demonstrated that, limb-specific imagery was impaired in both putamen and cortical lesions, in the first-, but not third-person task. Moreover, more than half of the errors made by cortical patients were with respect to the first movement, a finding consistent with motor cortex involvement in memory processes. Taken overall, the results provide evidence that the basal ganglia as well as cortical structures play an important role in the neural network mediating motor imagery.

An exploratory study of effects of smoking on mental rotation and mental paper-folding task

To demonstrate the positive effects of smoking on spatial-imagery processing, behavioral (hit ratio and reaction time) and physiological indices (EEGs and HR) were examined in 12 student volunteers. Subjects performed two spatial-imagery tasks, one mental rotation and the other mental paper-folding. The two tasks were performed before and after smoking and the results compared. Subjects participated in both control and smoking sessions. Reaction time decreased after smoking, while the hit ratio did not change. EEG contour maps derived from 12-channel records of the beta band showed activation of the frontal area during the spatial-imagery processing. After smoking, EEG laterality showed increased right-hemisphere dominance. These findings implied that smoking facilitated selective activation of the hemisphere and did not support Gilbert and Wesler's hypothesis of left-hemisphere priming. Psychophysiological mechanisms of the effects of smoking were discussed.

Reopening the mental imagery debate: lessons from functional anatomy

Over the past few years, the neural bases of mental imagery have been both a topic of intense debate and a domain of extensive investigations using either PET or fMRI that have provided new insights into the cortical anatomy of this cognitive function. Several studies have in fact demonstrated that there exist types of mental imagery that do not rely on primary/early visual areas, whereas a consensus now exists on the validity of the dorsal/ventral-route model in the imagery domain. More importantly, these studies have provided evidence that, in addition to higher order visual areas, mental imagery shares common brain areas with other major cognitive functions, such as language, memory, and movement, depending on the nature of the imagery task. This body of recent results indicates that there is no unique mental imagery cortical network; rather, it reflects the high degree of interaction between mental imagery and other cognitive functions.

Generalizing everyday memory: signs and handedness

Memory for frequently encountered road signs was investigated. In Experiment 1, the average level of recall of road sign features was found to be only 47%. In Experiment 2, more left-handed than right-handed people recalled that a walking figure faces right on one sign, whereas more right-handed than left-handed people recalled that a digging figure faces left on another sign. Performance thus reflected not a difference in level of mnemonic ability between left-handed and right-handed groups but instead the compatibility between group and task. In Experiment 3, participants were asked to draw any figure walking and any figure digging, with a pattern of results similar to that of Experiment 2. It is suggested that handedness effects in recall are mediated by motor imagery.

The mental representation of hand movements after parietal cortex damage

Recent neuroimagery findings showed that the patterns of cerebral activation during the mental rehearsal of a motor act are similar to those produced by its actual execution. This concurs with the notion that part of the distributed neural activity taking place during movement involves internal simulations, but it is not yet clear what specific contribution the different brain areas involved bring to this process. Here, patients with lesions restricted to the parietal cortex were found to be impaired selectively at predicting, through mental imagery, the time necessary to perform differentiated finger movements and visually guided pointing gestures, in comparison to normal individuals and to a patient with damage to the primary motor area. These results suggest that the parietal cortex is important for the ability to generate mental movement representations.

Secondary-task effects on sequence learning

With a repeated sequence of stimuli, performance in a serial reaction-time task improves more than with a random sequence. The difference has been taken as a measure of implicit sequence learning. Implicit sequence learning is impaired when a secondary task is added to the serial RT task. In the first experiment, secondary-task effects on different types of sequences were studied to test the hypothesis that the learning of unique sequences (where each sequence element has a unique relation to the following one) is not impaired by the secondary task, while the learning of ambiguous sequences is. The sequences were random up to a certain order of sequential dependencies, where they became deterministic. Contrary to the hypothesis, secondary-task effects on the learning of unique sequences were as strong or stronger than such effects on the learning of ambiguous sequences. In the second experiment a hybrid sequence (with unique as well as ambiguous transitions) was used with different secondary tasks. A visuo-spatial and a verbal memory task did not interfere with the learning of the sequence, but interference was observed with an auditory go/no-go task in which high- and low-pitched tones were presented after each manual response and a foot pedal had to be pressed in response to high-pitched tones. Thus, interference seems to be specific to certain secondary tasks and may be related to memory processes (but most likely not to visuo-spatial and verbal memory) or to the organizations of sequences, consistent with previous suggestions.

Imagery and perception-action mediation in imitative actions

This paper describes two lines of research exploring a hypothetical function of imagery in the context of imitative actions: the mediation between perceptual and motor processes. Both experimental approaches, a sequence learning task and a timing imitation task, demonstrate that engagement into imagery as a temporally distinct activity between observation and performance is not required for accurate imitation. Moreover, evidence is provided that generative processes can take place during event observation itself, thus making a separate recoding stage redundant. Nevertheless, in the absence of a visual display, imagery of a movement sequence exerted similar learning effects as physical and observational practice, and visual and motor imagery were found to be equally effective rehearsal strategies for maintenance of temporal information in short-term memory.

Mental motor imagery: a window into the representational stages of action

The physiological basis of mental states can be effectively studied by combining cognitive psychology with human neuroscience. Recent research has employed mental motor imagery in normal and brain-damaged subjects to decipher the content and the structure of covert processes preceding the execution of action. The mapping of brain activity during motor imagery discloses a pattern of activation similar to that of an executed action.