Postmovement Beta Rebound in Real and Imagined Movement.

Background. Imagined motor movement is a cognitive process in which a subject imagines a movement without doing it, which activates similar brain regions as during actual motor movement. Brain gamma band activity (GBA) is linked to cognitive functions such as perception, attention, memory, awareness, synaptic plasticity, motor control, and Imagination. Motor imagery can be used in sports to improve performance, raising the possibility of using it as a rehabilitation method through brain plasticity through mirror neurons. Method. A comparative observational study was conducted on 56 healthy male subjects after obtaining clearance from the Ethics Committee. EEG recordings for GBA were taken for resting, real, and imaginary motor movements and compared. The power spectrum of gamma waves was analyzed using the Kruskal-Wallis test; a p-value <.05 was considered significant. Results. The brain gamma rhythm amplitude was statistically increased during both actual and imaginary motor movement compared to baseline (resting stage) in most of the regions of the brain except the occipital region. There was no significant difference in GBA between real and imaginary movements. Conclusions. Increased gamma rhythm amplitude during both actual and imaginary motor movement than baseline (resting stage) indicating raised brain cognitive activity during both types of movements. There was no potential difference between real and imaginary movements suggesting that the real movement can be replaced by the imaginary movement to enhance work performance through mirror therapy.

AimsTo derive scores for mental disorganization and impoverishment from commonly used rating scales, and test the hypothesis that disorganization and impoverishment, along with impaired cognition and role-function reflect a latent variable that is a plausible candidate for the putative core deficit.BackgroundFor more than 100 years, disorganization and impoverishment of mental activity have been recognised as fundamental symptoms of schizophrenia. These symptoms may reflect a core brain process underlying persisting disability. Delusions and hallucinations have been regarded as accessory features. The psychopathological processes predisposing to persisting disability in schizophrenia are poorly understood. The delineation of a core deficit underlying persisting disability would be potentially of great value in predicting outcome and developing improved treatment.MethodPatients aged 18–55 years were included if: they satisfied DSM IV criteria for schizophrenia or schizoaffective disorder. Healthy controls were recruited by public advertisement and selected to match the patient group in age and sex. Study sample included 39 participants with schizophrenia, 1 with schizoaffective disorder and 44 matched healthy controls. We derived disorganization and impoverishment scores from three symptom scales: PANSS, SSPI and CASH. We computed composite scores for disorganization and for impoverishment and employed Confirmatory Factor Analysis to test the hypothesis that a single factor accounts for the relationships between disorganization, impoverishment, cognitive impairment and impaired role function. We assessed the relationship between this latent “core deficit” and diminished Post Movement Beta Rebound (PMBR), an electrophysiological measure from Magnetoencephalography (MEG), associated with persisting brain disorders.ResultFit indices for the single factor model from CFA indicated a good fit: χ2(2) = 1.817, p = .403; RMSEA &lt;.001 GFI = .979. PMBR was significantly reduced in the schizophrenia group compared to healthy controls, t (68) = 3.55, p &lt; .001. Within the patient group, PMBR was significantly and negatively correlated with the CFA factor scores representing the Core Deficit score, r=−.543, p &lt; .01, indicating that high core deficit scores were associated with reduced PMBR. PMBR was significantly correlated with the composite Disorganization score, r=−.521, p &lt; .001.ConclusionOur findings demonstrate that the shared variance between impoverishment (psychomotor poverty); disorganization; cognitive impairment; and impaired role function can be accounted for by a latent variable that can reasonably be described as the core deficit of classical schizophrenia. The demonstration that the severity of the putative core deficit is correlated with the reduction in PMBR provides evidence that the core deficit is associated with an identifiable abnormality of brain dysfunction.

A course of interactive stimulation of primary motor cortex (Brodmann area 4) in the brain of a stroke patient resulted in recovery of locomotion volume in the paretic extremities and in improvement of general health accompanied with diverse changes in cerebral activity. During the training course, the magnitude of response in the visual fields of Brodmann areas 17 and 18 decreased; in parallel, the motor areas were supplemented with other ones such as area 24 (the ventral surface of anterior cingulate gyrus responsible for self-regulation of human brain activity and implicated into synthesis of tactile and special information) in company with Brodmann areas 40, 41, 43, 44, and 45. EEG data showed that neurofeedback sessions persistently increased the θ rhythm power in Brodmann areas 7, 39, 40, and 47, while the corresponding powers progressively decreased during a real motion. Both real motion and its virtual sibling constructed by interactive stimulation via neurofeedback were characterized with decreasing powers of the EEG β rhythm in Brodmann areas 6 and 8. The neurofeedback course decreased the coherence between the left Brodmann area 6 and some other ones examined in α and θ ranges. In the context of real motions, the coherence assessed in the EEG β range generally increased. Overall, the EEG and fMRI parameters attest to growing similarity between the moieties of functional communications effected in real and imaginary movements during neurofeedback course. The data open the vista for interactive stimulation to rehabilitate stroke patients; they highlight the important role of Brodmann areas in rearrangement of the brain in such patients; finally, the present results revealed the "common nervous pathway" that can be used to restore the capability for imaginary and real movements by a neurofeedback course after stroke.

Hemispheric asymmetry of the ipsilateral silent period following voluntary movement of the opposite hand.

Relating MEG measured motor cortical oscillations to resting γ-Aminobutyric acid (GABA) concentration

Low-frequency neural activity at rest is correlated with the movement-related cortical potentials elicited during both real and imagined movements

Abnormalities of motor imagery associated with somatic passivity phenomena in schizophrenia

Functional near infrared spectroscopy as a probe of brain function in people with prolonged disorders of consciousness.

The role of GABAergic modulation in motor function related neuronal network activity

Bilateral upper-limb motor imagery has been demonstrated to be a useful mental task in electroencephalography (EEG)-based brain–computer interfaces (BCIs). By contrast, few studies have examined bilateral lower-limb motor imagery, and all of them have focused on imaginary foot movements. The left–right classification accuracy reported in these studies based on the EEG mu rhythm (8–13 Hz) and beta band (13–30 Hz) remains unsatisfactory. The present study investigated the possibility of using lower-limb stepping motor imagery as the mental task and analysed the EEG difference between imaginary left-leg stepping (L-stepping) and right-leg stepping (R-stepping) movements. An experimental paradigm was designed to collect 5-s motor imagery EEG signals at nine recording sites around the vertex of the brain. Results from eight able-bodied participants indicated that the commonly used mu event-related desynchronisation (ERD) feature exhibited no significant difference between the two imaginary movements for all recording sites and all time intervals within the 5-s motor imagery period. Regarding the other commonly used feature, beta event-related synchronisation, no significant difference between the two imagery tasks was observed for most of the recording sites and time intervals. Instead, theta band (4–8 Hz) ERD significantly differed between the L- and R-stepping imagery tasks at five sites (FC4, C3, CP3, Cz, CPz) within the first 2 s after motor imagery cue onset. The findings from the present study may be a basis for further development of BCI systems for decoding left and right stepping during mental exercise where the two motions are alternately imagined.

P 69 Assessing the relation between brain structure and function during motor imagery in stroke patients and controls using EEG and MRI

Objective To study the effect of intestinal bacteria on motor ability of amyotrophic lateral sclerosis (ALS) mice models and its mechanism. Methods Twenty wild type C57BL/6J mice (WT group) and 20 SOD1-G93A transgenic ALS mice (ALS group) were selected as the research subjects. (1) Ten mice in both WT group and ALS group were selected, respectively; 5 mice in each group were fed in SPF environment, and the remaining 5 mice were fed in aseptic environment; they were defined as WT+SPF group, WT+aseptic group, ALS+SPF group and ALS+aseptic group. (2) Ten mice in WT group and ALS group were fed in sterile environment; 5 mice in each group were transplanted with fecal bacteria, and the remaining 5 mice were not interfered; they were defined as WT+transplantation group, WT+non-transplantation group, ALS+transplantation group and ALS+non transplantation group. The grip strength of mice was measured by grip force meter, the motor coordination ability of mice was tested by roller treadmill and rotating rod test, the number of motor neurons in the anterior horn of spinal cord was measured by Nissl staining, the expression of microglia activation marker ionic calcium junction protein (IBA-1) in spinal cord tissues was detected by immunohistochemical staining, and the expressions of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in spinal cord tissues were detected by Western blotting; the β-N-methylamino-L-alanine (BMAA) expression was detected by high performance liquid chromatography-tandem mass spectrometry. Results (1) The grip strength, drop latency and drop time of ALS+aseptic mice were significantly higher than those of ALS+SPF mice, the number of Nissl-stained positive cells was significantly larger than that of ALS+SPF mice, the number of IBA-1 positive cells was significantly smaller than that of ALS+SPF mice, the levels of TNF-α and IL-6 protein expressions and BMAA concentration were statistically lower than those of ALS+SPF mice (P<0.05). (2) The grip strength, drop latency and drop time of ALS+transplantion mice were significantly lower than those of ALS+non-transplantation mice, the number of Nissl-stained positive cells was significantly smaller than that of ALS+non-transplantation mice, the number of IBA-1 positive cells was significantly larger than that of ALS+non-transplantation mice, the TNF-α and IL-6 protein expressions and BMAA concentration were significantly higher than those of ALS+non-transplantation mice (P<0.05). Conclusion Imbalance of intestinal bacteria homeostasis can decrease the motor ability of ALS mice, which is related to the activation of microglia. Key words: Amyotrophic lateral sclerosis; Intestinal bacteria; Motor ability; Motor neuron; Microglia

Motor imagery (MI) is defined as mental execution without any actual movement. While healthy adults usually show temporal equivalence, i.e., isochrony, between the mental simulation of an action and its actual performance, neurological disorders are associated with anisochrony. Unlike in patients with stroke and Parkinson disease, only a few studies have investigated differences of MI ability in multiple sclerosis (MS). However, the relationship among disease severity, anisochrony and brain activation patterns during MI has not been investigated yet. Here, we propose to investigate MI in MS patients using fMRI during a behavioral task executed with dominant/non-dominant hand and to evaluate whether anisochrony is associated with disease severity. Thirty-seven right-handed MS patients, 17 with clinically isolated syndrome (CIS) suggestive of MS and 20 with relapsing-remitting MS (RR-MS) and 20 right-handed healthy controls (HC) underwent fMRI during a motor task consisting in the actual or imaged movement of squeezing a foam ball with the dominant and non-dominant hand. The same tasks were performed outside the MRI room to record the number of actual and imagined ball squeezes, and calculate an Index of performance (IP) based on the ratio between actual and imagined movements. IP showed that a progressive loss of ability in simulating actions (i.e., anisochrony) more pronounced for non-dominant hand, was found as function of the disease course. Moreover, anisochrony was associated with activation of occipito-parieto-frontal areas that were more extensive at the early stages of the disease, probably in order to counteract the changes due to MS. However, the neural engagement of compensatory brain areas becomes more difficult with more challenging tasks, i.e., dominant vs. non-dominant hand, with a consequent deficit in behavioral performance. These results show a strict association between MI performance and disease severity, suggesting that, at early stages of the disease, anisochrony in MI could be considered as surrogate behavioral marker of MS severity.

Both discrete and continuous bimanual coordination patterns are difficult to effectively perform when the two limbs are required to perform different movements patterns, move at different velocities and/or move different amplitudes unless some form of integrated feedback is provided. The purpose of the present experiment was to determine the degree to which a complex bimanual coordination pattern could be performed when integrated feedback and movement template are provided. The complex bimanual coordination pattern involved reciprocal movements of the two limbs under different difficulty requirements. As defined by Fitts' index of difficulty (ID), the left arm (ID = 3, A = 16°, W = 4°) task was of lower difficulty than the right arm task (ID = 5, A = 32°, W = 2°). Note that the left and right limb movements are also different in terms of movement time, movement velocity, accuracy requirements and amplitude as well as one movement was continuous and the other intermittent. Participants were provided 2 blocks of 9 trials in the bimanual condition (30 s/trial). Following the bimanual phase, participants performed two unimanual test trials-one with each limb. The results demonstrated that the performance for each limb in the bimanual condition was similar to the performance for the same limb and conditions in the unimanual control conditions. The similarity was indicated by the same movement speed, movement structure, endpoint variability and hit rates for the bimanual and unimanual conditions. The results support our hypothesis that people can overcome the intrinsic difficulties associated with performing complex bimanual coordination patterns when provided appropriate perceptual information feedback that allows them to detect and correct coordination errors.

Focusing on low-cost articulation control for neuroprosthesis, electroencephalography (EEG)-based brain computer interfaces require rapid and reliable discrimination of EEG patterns associated with motor imagery generated via imagined or real movement. The objective of this study was to characterize EEG signals of two different motor imagery tasks used to control a robotic articulator. With one-sided hand movement imagination resulting in EEG changes located contra and ipsilateral areas, time-courses of two different imagery tasks were investigated via instantaneous band power changes. We compared the features extracted from the EEG patterns with standard machine learning algorithms. We report frequency-based categorization of visualized imagery more relevant than machine learning methods.