Finger Opposition Task Research Articles

Symmetric bimanual coordination discrepancy and activities of daily living in individuals with autism spectrum disorder

Impairments in bimanual coordination are commonly observed in individuals with autism spectrum disorder (ASD). Bimanual coordination is essential for the performance of activities of daily living (ADLs). However, it remains unclear whether bimanual coordination impairment is associated with performing ADLs in adults with ASD. This study examined the relationship between bimanual tasks and subjective ADL difficulty in adults with ASD. Nineteen adults with ASD (41.95 ± 10.89) and 20 aged-matched (41.70 ± 11.07) controls completed a bimanual thumb–index finger opposition task and a questionnaire on subjective difficulty in ADL performance, which was evaluated using a visual analogue scale. The bimanual thumb–index finger opposition task was evaluated using a motion capture system, which quantified the coefficient of variation (COV) between bilateral finger movements. The subjective ADL difficulty scores were significantly higher in adults with ASD than in controls (p = 0.003). The COV in adults with ASD was also higher than in controls (p = 0.025). A moderate correlation was found between bimanual task COVs and subjective ADL difficulty scores in adults with ASD (r = 0.56, p = 0.013). Thus, a discrepancy in bimanual coordination may increase the effort required to perform ADLs in adults with ASD.

The online and offline effects of changing movement timing variability during training on a finger-opposition task

In motor learning tasks, there is mixed evidence for whether increased task-relevant variability in early learning stages leads to improved outcomes. One problem is that there may be a connection between skill level and motor variability, such that participants who initially have more variability may also perform worse on the task, so will have more room to improve. To avoid this confound, we experimentally manipulated the amount of movement timing variability (MTV) during training to test whether it improves performance. Based on previous studies showing that most of the improvement in finger-opposition tasks comes from optimizing the relative onset time of the finger movements, we used auditory cues (beeps) to guide the onset times of sequential movements during a training session, and then assessed motor performance after the intervention. Participants were assigned to three groups that either: (a) followed a prescribed random rhythm for their finger touches (Variable MTV), (b) followed a fixed rhythm (Fixed control MTV), or (c) produced the entire sequence following a single beep (Unsupervised control MTV). While the intervention was successful in increasing MTV during training for the Variable group, it did not lead to improved outcomes post-training compared to either control group, and the use of fixed timing led to significantly worse performance compared to the Unsupervised control group. These results suggest that manipulating MTV through auditory cues does not produce greater learning than unconstrained training in motor sequence tasks.

Interictal hemodynamic abnormality during motor activation in sporadic hemiplegic migraine: An explorative study

IntroductionThe motor weakness in sporadic hemiplegic migraine (SHM) is a poorly understood aura manifestation. Cortical spreading depression affecting motor excitability and alterations of neurovascular coupling may be integral to the development of migraine aura. MethodsWe studied 10 right-handed SHM patients and 17 healthy controls with functional near-infrared spectroscopy (fNIRS) in the interictal period. Subjects performed a finger opposition task and had real time determination of oxyhemoglobin (OxyHb) and deoxyhemoglobin (deOxyHb) changes. Recordings were completed with 10 left and 10 right sided cortical channels. ResultsMean baseline to peak changes were significantly reduced in SHM patients as compared to controls bilaterally only for OxyHb measurements in the anteromedial channels. Mean time to peak changes were significant delayed in SHM patients compared to controls bilaterally largely for OxyHb measurements in the posterolateral channels, with the exception of 2 recording channels. ConclusionsOur findings suggest presence of abnormal interictal hemodynamic responses to increased metabolic demands during motor activation in SHM. These bilateral cerebrovascular changes involve OxyHb to a much larger degree than deOxyHb. Baseline to peak changes were evident more in the anteromedial channels, whereas time to peak changes were more evident in the posterolateral channels. These findings suggest that oxygen inflow into specific brain regions may be defective in SHM as opposed to oxygen utilization. Our findings suggest that in SHM, enduring hemodynamic deficits in response to an impending motor task are evident, which can be further explored in future studies, and possibly therapeutic trials.

Contra-Lateral Unintended Upper Arm Movement during Unimanual Tasks in Children with Cerebral Palsy.

PurposeTo characterize associated reactions (ARs) in the contralateral arm across multiple muscles during unimanual tasks and to identify factors related to ARs in children with cerebral palsy (CP).Materials and MethodsThis was a prospective, cross-sectional study of 35 children with CP. The extent of ARs of the contra-lateral, non-task hand was assessed while performing three unimanual tasks (opening and clenching the fist, a finger opposition task, and tapping fingers). The occurrence of ARs in each trial was evaluated separately for each task using a four-point scale (total scores ranged from 0 to 12). Surface electromyography (SEMG) was used to measure the firing activity of the muscles of the opposite arm during the task. The Manual Ability Classification System and Melbourne Assessment 2 (MA-2) were used to evaluate upper limb function.ResultsAR scores were higher in the more-affected limb than in the less-affected limb. SEMG data on the non-task hand showed motor overflow up to the elbow muscles in the more-affected limb. Root mean square ratios of EMG signals were significantly higher in children with ARs than in children without ARs. Multiple regression analysis showed both age and MA-2 to be significant factors related to ARs in the more-affected limb.ConclusionChildren with visible ARs showed motor overflow in the non-task limb during unimanual hand tasks. Age and upper limb function were significantly related to the extent of ARs in the more-affected limb of children with CP.

Concurrent anodal transcranial direct-current stimulation and motor task to influence sensorimotor cortex activation

Functional targeting with anodal high-definition transcranial direct current stimulation (HD-atDCS) of involved brain areas during performance of a motor task (online) may facilitate sensorimotor cortex neuroplasticity compared to performing the motor task after HD-atDCS (offline). The aim of this study was to employ functional near-infrared spectroscopy to compare the time course of motor task-related changes in sensorimotor cortex activation between online and offline HD-atDCS. We hypothesized that online HD-atDCS would have a greater effect on task-related sensorimotor cortex activation than offline HD-atDCS. In a within-subject sham controlled and randomized study design, 9 healthy participants underwent 3 HD-atDCS sessions (online, offline and sham) targeting the left sensorimotor cortex separated by 1 week. Functional near-infrared spectroscopy hemodynamic changes were measured from the left sensorimotor cortex during a simple finger opposition motor task before (Pre), immediately (T1) and 30 min after (T2) each session. The movement rates were not different between (online, offline, sham) or within (Pre, T1, T2) sessions. At T2, online HD-atDCS was associated with a significant increase (large effect size) in sensorimotor cortex activation (Hedges g = 1.01, p < 0.001) when compared to sham; there was a nonsignificant trend to increase activation between offline and sham (Hedges g = 0.52, p = 0.05) and between online and offline (Hedges g = 0.53, p = 0.06). Concurrent application of HD-atDCS during a motor task may produce larger sensorimotor cortex activation than sequential application.

Thumbs up: movements made by the thumb are smoother and larger than fingers in finger-thumb opposition tasks.

BackgroundIn humans, the thumb plays a crucial role in producing finger opposition movements. These movements form the basis of several activities of the hand. Hence these movements have been used to study phenomena like prehension, motor control, motor learning, etc. Although such tasks have been studied extensively, the relative contribution of the thumb vis-à-vis the fingers in finger opposition tasks is not well understood. In this study, we investigated the kinematics of thumb and fingers in a simple finger opposition task. Further, we quantified the relative contribution and the movement smoothness aspects and compared these between fingers and thumb.MethodsEight, young healthy participants (four males and four females) were asked to perform a full finger to thumb opposition movement, where they were required to reach for different phalanges of the fingers. Position (X, Y and Z) of individual segments of the four fingers and the thumb were measured with reference to the wrist by a 16-sensor kinematics measurement system. Displacements and velocities were computed. An index, displacement ratio, that quantifies the relative contribution of thumb and fingers was computed from displacement data. Velocity data was used to quantify the smoothness of movement of thumb and fingers.ResultsThe Displacement Ratio showed that contribution of the thumb is higher than contribution of any other target finger or target phalanges, except for the distal phalanx of the index and middle fingers. Smoothness of movement of the thumb was higher than all the finger phalanges in all cases.ConclusionWe conclude that in the task considered (thumb opposition movements to different targets within the hand & fingers), the thumb made a greater relative contribution in terms of displacement ratio and also produced smoother movements. However, smoothness of thumb did not vary depending on the target. This suggests that the traditional notion of the thumb being a special digit when compared to other fingers is true at least for the opposition movements considered in this study.

Motor imagery in chronic neglect: An fMRI pilot study

ABSTRACTAim. Previous studies indicate the effectiveness of motor imagery training in stroke patients. To determine whether patients showing chronic visuospatial neglect symptoms may profit from motor imagery training, it is important to assess how the brain implements motor imagery when cortical systems involved in attentional control are impaired.Method. Therefore, in this pilot study, nine chronic neglect patients with right-hemispheric stroke performed motor imagery of a finger opposition task during functional magnetic resonance imaging (fMRI).Results. Imagery of unaffected hand movements was related to activations in the left primary somatosensory and premotor cortices as well as in the left supplementary motor area. During the imagery of the affected hand, patients displayed activations in the left premotor cortex and supplementary motor area as well as left dorsolateral prefrontal cortex. Furthermore, time since onset and visual imagery capacity were negatively related to activation in the supplementary motor area during the imagery of the affected hand.Conclusions. These initial results demonstrate motor imagery capacity in patients with chronic neglect via compensatory neural processing during motor imagery of the affected hand in ipsilateral brain regions, since we found that the supplementary motor area appears to be specifically related to neglect severity. Although our results must be treated with caution due to the small sample size and missing control group, they indicate that neglect is not necessarily an exclusion criterion for motor imagery training per se.

The effects of TDCS stimulation on motor learning in healthy and severe sub-acute traumatic brain injury adults

Procedural learning is a basic mechanism for acquisition of basic motor and cognitive skills. Optimizing this process using both training strategies and innovative technology is of great importance in rehabilitation of patients with traumatic brain injury (TBI), an important cause of severe disability. Recently an expanding body of evidence indicated that trans-Cranial Direct Current Stimulation (tDCS) may positively affect procedural learning. 1. Characterize the effect of tDCS on motor skill learning in healthy adults using the finger-to-thumb opposition sequence paradigm (FOS). 2. Compare the findings to those of sub-acute TBI patients. Thirty healthy and ten sub-acute TBI participants were included in a randomized double-blind, controlled trial. Participants were trained to perform a finger opposition task. The study group (20 participants) received anodal stimulation over the motor cortex contralateral to the performing hand, and the control group (20 patients) received “sham” stimulation. Performance (speed and accuracy) were tested before, immediately after and 24 h post-training. Retention was tested one week later. tDCS stimulation resulted in increased speed with no accuracy trade-off in healthy participants compared to controls, in the consolidation (37.4% vs. 30.6% improvement compared with initial speed) and retention stages (41.9% vs. 37.8%). The relative effect of tDCS was larger in the TBI group in both consolidation and retention stages (1.32 and 1.27, respectively). However, neither effects reached significance. Our results are in line with previous findings that showed a positive effect of tDCS on learning but largre cohort studies are needed to substantiate this claim.

A tug of war: antagonistic effective connectivity patterns over the motor cortex and the severity of motor symptoms in Gilles de la Tourette syndrome.

We tested the hypothesis that Gilles de la Tourette syndrome (GTS) is characterized by perturbed connectivity within cortico-subcortical motor networks. To this end, we performed a dynamic causal modelling (DCM) analysis of fMRI data collected during a finger opposition task in 24 normal controls and 24 GTS patients. The DCM analysis allowed us to assess whether any GTS-specific patterns of brain activity were related to intrinsic and/or to task-dependent connectivity. While no abnormalities were found for task-dependent connectivity, intrinsic connectivity was abnormally increased in the premotor network, with stronger connections from the supplementary motor area (SMA), from the dorsolateral premotor cortex and from the putamen to the right superior frontal gyrus, an area where GTS showed over-activation in a previous univariate analysis. We also found a positive correlation between the connectivity strength from the right basal ganglia to the right primary motor cortex (M1) and disease severity measured by the Yale Global Tic Severity Scale (YGTSS). This pattern was mirrored by a negative correlation between the connection strength from the right SMA to the right area M1 and the YGTSS score. These two reverse correlation effects showed a specific relationship with individual disease severity: the greater the imbalance between subcortical and premotor connectivity towards area M1, the higher the YGTSS score. These results reveal the existence of perturbed intrinsic connectivity patterns in the motor networks of GTS patients with two competing forces operating in a tug of war-like mechanism: aberrant subcortical afferents to M1, compensated for by inputs from the premotor cortex.

Abnormal lateralization of fine motor actions in Tourette syndrome persists into adulthood.

Youth with Tourette syndrome (TS) exhibit, compared to healthy, abnormal ability to lateralize digital sequential tasks. It is unknown whether this trait is related to inter-hemispheric connections, and whether it is preserved or lost in patients with TS persisting through adult life. We studied 13 adult TS patients and 15 age-matched healthy volunteers. All participants undertook: 1) a finger opposition task, performed with the right hand (RH) only or with both hands, using a sensor-engineered glove in synchrony with a metronome at 2 Hz; we calculated a lateralization index [(single RH–bimanual RH)/single RH X 100) for percentage of correct movements (%CORR); 2) MRI-based diffusion tensor imaging and probabilistic tractography of inter-hemispheric corpus callosum (CC) connections between supplementary motor areas (SMA) and primary motor cortices (M1). We confirmed a significant increase in the %CORR in RH in the bimanual vs. single task in TS patients (p<0.001), coupled to an abnormal ability to lateralize finger movements (significantly lower lateralization index for %CORR in TS patients, p = 0.04). The %CORR lateralization index correlated positively with tic severity measured with the Yale Global Tic Severity Scale (R = 0.55;p = 0.04). We detected a significantly higher fractional anisotropy (FA) in both the M1-M1 (p = 0.036) and the SMA-SMA (p = 0.018) callosal fibre tracts in TS patients. In healthy subjects, the %CORR lateralization index correlated positively with fractional anisotropy of SMA-SMA fibre tracts (R = 0.63, p = 0.02); this correlation was not significant in TS patients. TS patients exhibited an abnormal ability to lateralize finger movements in sequential tasks, which increased in accuracy when the task was performed bimanually. This abnormality persists throughout different age periods and appears dissociated from the transcallosal connectivity of motor cortical regions. The altered interhemispheric transfer of motor abilities in TS may be the result of compensatory processes linked to self-regulation of motor control.

Effects of Mental and Physical Practice on a Finger Opposition Task Among Children

Purpose: We sought to compare the effects of physical practice (PP) and mental practice (MP) on the immediate and long-term learning of the finger-to-thumb opposition sequence task (FOS) in children; in addition, we investigated the transfer of this learning to an untrained sequence of movements and to the contralateral untrained hand. Method: This study included thirty-six 9- and 10-year-old children who were randomly allocated into 3 groups: MP, PP, and no practice (NP). The MP and PP groups were subjected to a single session of training with the dominant trained hand. MP participants were trained by mentally rehearsing the movements, PP participants were trained by executing the movements, and the NP group had no training. The performance of the trained sequence (TS) and untrained reverse sequence (URS) by each of the 3 groups was evaluated under identical conditions before training, after 5 min, and at 4 days, 7 days, and 28 days after training. Results: Whereas both trained groups (MP and PP) showed statistically significant improvement in TS using the trained hand at all assessment points after the training, only MP participants were able to transfer the performance gains from the TS to the URS and from the trained hand to the untrained opposite hand. Conclusion: Children were able to learn the FOS through MP or PP with a similar level of performance. Unlike PP, MP allowed for the transfer of performance gain to the URS and to the opposite hand, suggesting that the internal representations developed by MP were effector-independent.

Reliability of negative BOLD in ipsilateral sensorimotor areas during unimanual task activity

Research using functional magnetic resonance imaging has for numerous years now reported the existence of a negative blood oxygenation level dependent (BOLD) response. Based on accumulating evidence, this negative BOLD signal appears to represent an active inhibition of cortical areas in which it is found during task activity. This particularly important with respect to motor function given that it is fairly well-established that, in younger adults, the ipsilateral sensorimotor cortex exhibits negative BOLD during unimanual movements in fMRI. This interhemispheric suppression of cortical activity may have useful implications for our understanding of both basic motor function and rehabilitation of injury or disease. However, to date, we are aware of no study that has tested the reliability of evoked negative BOLD in ipsilateral sensorimotor cortex in individuals across sessions. The current study employs a unimanual finger opposition task previously shown to evoke negative BOLD in ipsilateral sensorimotor cortex across three sessions. Reliability metrics across sessions indicates that both the magnitude and location of ipsilateral sensorimotor negative BOLD response is relatively stable over each of the three sessions. Moreover, the volume of negative BOLD in ipsilateral cortex was highly correlated with volume of positive BOLD activity in the contralateral primary motor cortex. These findings show that the negative BOLD signal can be reliably evoked in unimanual task paradigms, and that the signal dynamic could represent an active suppression of the ipsilateral sensorimotor cortex originating from the contralateral motor areas.

Observation of Simple Intransitive Actions: The Effect of Familiarity

IntroductionHumans are more familiar with index – thumb than with any other finger to thumb grasping. The effect of familiarity has been previously tested with complex, specialized and/or transitive movements, but not with simple intransitive ones. The aim of this study is to evaluate brain activity patterns during the observation of simple and intransitive finger movements with differing degrees of familiarity.MethodologyA functional Magnetic Resonance Imaging (fMRI) study was performed using a paradigm consisting of the observation of 4 videos showing a finger opposition task between the thumb and the other fingers (index, middle, ring and little) in a repetitive manner with a fixed frequency (1 Hz). This movement is considered as the pantomime of a precision grasping action.ResultsSignificant activity was identified in the bilateral Inferior Parietal Lobule and premotor regions with the selected level of significance (FDR [False Discovery Rate] = 0.01). The extent of the activation in both regions tended to decrease when the finger that performed the action was further from the thumb. More specifically, this effect showed a linear trend (index>middle>ring>little) in the right parietal and premotor regions.ConclusionsThe observation of less familiar simple intransitive movements produces less activation of parietal and premotor areas than familiar ones. The most important implication of this study is the identification of differences in brain activity during the observation of simple intransitive movements with different degrees of familiarity.

Effect of observation of simple hand movement on brain activations in patients with unilateral cerebral palsy: an fMRI study

The aim of this functional magnetic resonance imaging (fMRI) study was to examine and compare brain activation in patients with unilateral cerebral palsy (CP) during observation of simple hand movement performed by the paretic and nonparetic hand. Nineteen patients with clinical unilateral CP (14 male, mean age 14 years, 7-21 years) participated in the study. Hand motor impairment was assessed using the sequential finger opposition task. Using fMRI block design, brain activation was examined following observation at rest of a simple opening-closing hand movement, performed by either the left or right hand of an actor. Eighteen fMRI dataset were analyzed. Observing hand movement produced large bilateral activations in temporo-parieto-fronto-occipital network, comprising most of the nodes of the well described action-observation network. For either side, observing hand movements recruits the primary motor cortex (M1), contralateral to the viewed hand, as would be expected in healthy persons. Viewing movement performed by an actor's hand representing the paretic side of patients activated more strongly ipsilesional M1 than viewing movement performed by an actor's hand representing the nonparetic side of patients. Observation of hand movement in patients with CP engaged the motor execution network regardless of the degree of motor impairment.

Intracortical modulation of somatosensory evoked fields during movement: Evidence for selective suppression of postsynaptic inhibition

As accurate finger movements depend on guidance by afferent sensory feedback information, it is of interest to examine how the cortical processing of afferent signals is altered during movement states compared with rest. In the present study we evaluated afferent input to the primary somatosensory cortex (SI) in human subjects performing a finger opposition task. We recorded somatosensory evoked magnetic fields (SEFs) in 6 healthy subjects to stimulation of left and right median nerves in a resting condition and during active right-sided finger movements. At the left SI, the SEFs to right (moving hand) median nerve stimulation showed a selective and robust reduction of the P35m deflection during movement compared with rest, while there were only minor non-significant changes in the other SEF deflections, including N20m, which represents the 1st excitatory cortical event after stimulation. In contrast, at the right SI the SEFs to left (non-moving hand) median nerve stimulation were modified in the opposite direction: the P35m deflection was slightly enhanced during right-sided movement, there being no significant changes in the other deflections. The results thus show that the P35m SEF deflection can be selectively reduced during finger movements of the stimulated hand, and selectively enhanced if the movement is being performed with the fingers of the opposite hand. Because N20m was not changed, the modulation took place at the cortical level rather than in the afferent pathways. As the P35m SEF deflection likely represents postsynaptic IPSPs at SI, the results suggest that postsynaptic inhibition to somatosensory impulses from the moving part of the body is suppressed. Comparison of the present results with recent intracellular studies in behaving mice suggests that the P35m reduction specifically corresponds to a reduction in the activity of parvalbumin-containing fast-spiking inhibitory interneurons during movement. The results provide evidence that precision movements can be executed without this type of cortical postsynaptic inhibition.

The role of proprioception in the consolidation of ipsilateral 1Hz-rTMS effects on motor performance

ObjectivesThe aim of the present work is to investigate whether the longlasting effect of the ipsilateral primary motor cortex (ipsiM1) 1Hz-repetitive transcranial magnetic stimulation (1Hz-rTMS) on motor performance can be modulated by subsequent engagement of the sensorimotor system through muscle vibration. MethodsTwenty-one subjects were divided into three groups: MOVEMENT group performed the 1min-finger opposition task before (PRE), immediately after (POST0), 15min (POST15) and 30min after (POST30) the 1Hz-rTMS on ipsiM1; the REST and VIBRATION groups performed the finger opposition task only at PRE and POST30. However, in the VIBRATION group at POST0 and POST15 the right flexor carpi radialis (FCR) was vibrated for 1min. Motor performance was recorded at PRE and POST30. ResultsThe MOVEMENT and VIBRATION groups showed at POST30 similar and significant changes in motor performance. A decrease in movement time and an increase in touch duration with no change in the ability to follow the metronome cue were observed. Motor performance did not change in the REST group at POST30. ConclusionsThese findings suggest that vibration of FCR can interact with rTMS cortical effects in a similar way to the voluntary movement. SignificanceMuscle vibration might be used in a rehabilitative setting to consolidate rTMS effects in patients with sensory pathways preserved.

TWave: High-order analysis of functional MRI

The traditional approach to functional image analysis models images as matrices of raw voxel intensity values. Although such a representation is widely utilized and heavily entrenched both within neuroimaging and in the wider data mining community, the strong interactions among space, time, and categorical modes such as subject and experimental task inherent in functional imaging yield a dataset with "high-order" structure, which matrix models are incapable of exploiting. Reasoning across all of these modes of data concurrently requires a high-order model capable of representing relationships between all modes of the data in tandem. We thus propose to model functional MRI data using tensors, which are high-order generalizations of matrices equivalent to multidimensional arrays or data cubes. However, several unique challenges exist in the high-order analysis of functional medical data: naïve tensor models are incapable of exploiting spatiotemporal locality patterns, standard tensor analysis techniques exhibit poor efficiency, and mixtures of numeric and categorical modes of data are very often present in neuroimaging experiments. Formulating the problem of image clustering as a form of Latent Semantic Analysis and using the WaveCluster algorithm as a baseline, we propose a comprehensive hybrid tensor and wavelet framework for clustering, concept discovery, and compression of functional medical images which successfully addresses these challenges. Our approach reduced runtime and dataset size on a 9.3GB finger opposition motor task fMRI dataset by up to 98% while exhibiting improved spatiotemporal coherence relative to standard tensor, wavelet, and voxel-based approaches. Our clustering technique was capable of automatically differentiating between the frontal areas of the brain responsible for task-related habituation and the motor regions responsible for executing the motor task, in contrast to a widely used fMRI analysis program, SPM, which only detected the latter region. Furthermore, our approach discovered latent concepts suggestive of subject handedness nearly 100× faster than standard approaches. These results suggest that a high-order model is an integral component to accurate scalable functional neuroimaging.

Motor sequence learning: Acquisition of explicit knowledge is concomitant to changes in motor strategy of finger opposition movements

Motor sequence learning is not a unitary phenomenon, but involves optimizing different components that include declarative and procedural aspects. In this work we designed an experimental approach that allows monitoring all the aspects of sequence learning using a finger opposition task and a movement-by-movement analysis. Subjects performed a visuomotor sequence learning paradigm with (Explicit) or without (Implicit) instructions and we measured response time (RT) and touch duration (TD) for each finger opposition movement of the sequence. Our results indicated that sequence learning induced a double-faced effect on motor performance: a decrease of RT and an increase of TD. However, the above changes manifested differently among subjects: all subjects that, by the end of session, had complete recall of the sequence order, reached an equal level of performance by the last sequence block while in those who had on average only a poor recall of the sequence order, learning was evident only as a slight decrease of RT across sequence blocks, while no kinematic changes (i.e., changes in TD) occurred. Our results indicate that, in the absence of specific instructions, learning evolves from an early stage in which only small decreases of RT are observed to a phase in which progressive knowledge of the sequential structure allows for dramatic changes of RT, together with a progressive change of motor performance (i.e., changes in TD).

Identificación intraoperatoria del área motora suplementaria en cirugía neurooncológica

The main objective of the present work was to identify, by means of intraoperative electrical stimulation, the supplementary motor area (SMA) region which is implicated in complex motor function. The functional prognostic relevance of the surgical preservation of this area was also analyzed. Fifteen patients with tumors infiltrating the premotor cortex were selected. All patients were operated under awake conditions. Primary motor cortex was identified with intraoperative electrical stimulation (IES). To identify the SMA, patients were asked to do a finger opposition motor task with their hand contralateral to the lesion, that was blocked by electrically stimulating the premotor cerebral cortex. SMA was identified in all patients with IES. Complete surgical resection was achieved in 13 patients (86.6%) and subtotal in 2 patients (13.3%). SMA function was preserved in 14 patients (93.3%). In only one patient the SMA was partially resected because of tumor infiltration (6.6%). In the immediate postoperative period, 8 patients (53.3%) did not show changes in comparison to their preoperative clinical status, and 2 patients improved. At 6 months follow up, 5 patients (33.3%) were asymptomatic and 10 patients showed permanent deficits. In this last group, five patients (33.3%) showed mild deficits that did not interfere with a normal life. In the other 5 patients (33.3%), permanent deficits interfered with daily life activities: two patients presented severe hemiparesis 3/5 (same similar to their preoperative status with no improvement), one patient had motor aphasia, and two other patients (13.3%) showed permanent left SMA syndrome. In two patients with severe postoperative hemiparesis, tumor infiltration of primary motor cortex and piramidal pathway was observed; severe preoperative motor deficit (KPS <70) was associated with poor functional outcome. Intraoperative electrical cortical stimulation is useful to identify the SMA. Once identified, SMA preservation decreases the risk of postoperative symptoms and permanent SMA syndrome. When SMA is infiltrated by the tumor, radical resection may cause permanent neurological deficits, specially in the dominant hemisphere. Severe preoperative motor deficit was associated with poor outcome.

Motor imagery influences the execution of repetitive finger opposition movements

Motor imagery (MI) is the ability to imagine performing a movement without executing it. In literature, there have been numerous reports on the influence of MI on motor practice and the beneficial effects of “mental practice” on the physical performance has been suggested to rely to the close temporal association between motor rehearsal and actual performance. In the present study, we aimed to evaluate whether the addition of a period of motor imagery between two motor practice trials could modify movement execution in a repetitive finger opposition motor task performed at maximal speed and whether the effect of motor imagery on motor practice is dependant on the complexity of movement. We observed that the addition of motor imagery to the sole motor practice was able to influence the performance of repetitive finger opposition movements inducing an increase of the velocity of movement greater than that observed with the motor practice alone. Further the addition of motor imagery was able to induce a modification in the motor strategy in terms of duration of the main phases of movements. This was more evident when subjects executed a finger sequential task with respect to a simple finger tapping task. We assume that mental rehearsal facilitates the brain network involved in sensorimotor control, particularly acting on those neural structures involved in the motor program.