Post-movement Beta Synchronization Research Articles

Beta rebound reduces subsequent movement preparation time by modulating of GABAA inhibition.

Post-movement beta synchronization is an increase of beta power relative to baseline, which commonly used to represent the status quo of the motor system. However, its functional role to the subsequent voluntary motor output and potential electrophysiological significance remain largely unknown. Here, we examined the reaction time of a Go/No-Go task of index finger tapping which performed at the phases of power baseline and post-movement beta synchronization peak induced by index finger abduction movements at different speeds (ballistic/self-paced) in 13 healthy subjects. We found a correlation between the post-movement beta synchronization and reaction time that larger post-movement beta synchronization prolonged the reaction time during Go trials. To probe the electrophysiological significance of post-movement beta synchronization, we assessed intracortical inhibitory measures probably involving GABAB (long-interval intracortical inhibition) and GABAA (short-interval intracortical inhibition) receptors in beta baseline and post-movement beta synchronization peak induced by index finger abduction movements at different speeds. We found that short-interval intracortical inhibition but not long-interval intracortical inhibition increased in post-movement beta synchronization peak compared with that in the power baseline, and was negatively correlated with the change of post-movement beta synchronization peak value. These novel findings indicate that the post-movement beta synchronization is related to forward model updating, with high beta rebound predicting longer time for the preparation of subsequent movement by inhibitory neural pathways of GABAA.

Event-related EEG synchronization and desynchronization in patients with obsessive-compulsive disorder.

Symptoms in patients with obsessive-compulsive disorder (OCD) are associated with impairment in cognitive control, attention, and action inhibition. We investigated OCD group differences relative to healthy subjects in terms of event-related alpha and beta range synchronization (ERS) and desynchronization (ERD) during a visually cued Go/NoGo task. Subjects were 62 OCD patients and 296 healthy controls (HC). The OCD group in comparison with HC, showed a changed value of alpha/beta oscillatory power over the central cortex, in particular, an increase in the alpha/beta ERD over the central-parietal cortex during the interstimulus interval (Cue condition) as well as changes in the postmovement beta synchronization topography and frequency. Over the frontal cortex, the OCD group showed an increase in magnitude of the beta ERS in NoGo condition. Within the parietal-occipital ERS/ERD modulations, the OCD group showed an increase in the alpha/beta ERD over the parietal cortex after the presentation of the visual stimuli as well as a decrease in the beta ERD over the occipital cortex after the presentation of the Cue and Go stimuli. The specific properties in the ERS/ERD patterns observed in the OCD group may reflect high involvement of the frontal and central cortex in action preparation and action inhibition processes and, possibly, in maintaining the motor program, which might be a result of the dysfunction of the cortico-striato-thalamo-cortical circuits involving prefrontal cortex. The data about enhanced involvement of the parietal cortex in the evaluation of the visual stimuli are in line with the assumption about overfocused attention in OCD.

Effect of Task Complexity on the Post-Movement Beta Synchronization in the Sensorimotor Cortex

Effect of Task Complexity on the Post-Movement Beta Synchronization in the Sensorimotor Cortex

Reduced readiness potential and post-movement beta synchronization reflect self-disorders in early course schizophrenia

Disturbances of conscious awareness, or self-disorders, are a defining feature of schizophrenia. These include symptoms such as delusions of control, i.e. the belief that one’s actions are controlled by an external agent. Models of self-disorders point at altered neural mechanisms of source monitoring, i.e. the ability of the brain to discriminate self-generated stimuli from those driven by the environment. However, evidence supporting this putative relationship is currently lacking. We performed electroencephalography (EEG) during self-paced, brisk right fist closures in ten (M = 9; F = 1) patients with Early-Course Schizophrenia (ECSCZ) and age and gender-matched healthy volunteers. We measured the Readiness Potential (RP), i.e. an EEG feature preceding self-generated movements, and movement-related EEG spectral changes. Self-disorders in ECSCZ were assessed with the Examination of Anomalous Self-Experience (EASE). Patients showed a markedly reduced RP and altered post-movement Event-Related Synchronization (ERS) in the beta frequency band (14–24 Hz) compared to healthy controls. Importantly, smaller RP and weaker ERS were associated with higher EASE scores in ECSCZ. Our data suggest that disturbances of neural correlates preceding and following self-initiated movements may reflect the severity of self-disorders in patients suffering from ECSCZ. These findings point towards deficits in basic mechanisms of sensorimotor integration as a substrate for self-disorders.

Watching the Brain as It (Un)Binds: Beta Synchronization Relates to Distractor-Response Binding.

Human action control relies on event files, that is, short-term stimulus-response bindings that result from the integration of perception and action. The present EEG study examined oscillatory brain activities related to the integration and disintegration of event files in the distractor-response binding (DRB) task, which relies on a sequential prime-probe structure with orthogonal variation of distractor and response relations between prime and probe. Behavioral results indicated a DRB effect in RTs, which was moderated by the duration of the response-stimulus interval (RSI) between prime response and probe stimulus onset. Indeed, a DRB effect was observed for a short RSI of 500 msec but not for a longer RSI of 2000 msec, indicating disintegration of event files over time. EEG results revealed a positive correlation between individual DRB in the RSI-2000 condition and postmovement beta synchronization after both prime and probe responses. Beamformer analysis localized this correlation effect to the middle occipital gyrus, which also showed highest coherency with precentral and inferior parietal brain regions. Together, these findings suggest that postmovement beta synchronization is a marker of event file disintegration, with the left middle occipital gyrus being a hub region for stimulus-response bindings in the visual DRB task.

Movement speed effects on beta-band oscillations in sensorimotor cortex during voluntary activity.

Beta-band oscillations are a dominant feature in the sensorimotor system, which includes movement-related beta desynchronization (MRBD) during the preparation and execution phases of movement and postmovement beta synchronization (PMBS) on movement cessation. Many studies have linked this rhythm to motor functions. However, its associations to the movement speed are still unclear. We make a hypothesis that PMBS will be modulated with increasing of movement speeds. We assessed the MRBD and PMBS during isotonic slower self-paced and ballistic movements with 15 healthy subjects. Furthermore, we conduct an additional control experiment with the isometric contraction with two levels of forces to match those in the isotonic slower self-paced and ballistic movements separately. We found that the amplitude of PMBS but not MRBD in motor cortex is modulated by the speed during voluntary movement. PMBS was positively correlated with movement speed and acceleration through the partial correlation analysis. However, there were no changes in the PMBS and MRBD during the isometric contraction with two levels of forces. These results demonstrate a different function of PMBS and MRBD to the movement speed during voluntary activity and suggest that the movement speed would affect the amplitude of PMBS.NEW & NOTEWORTHY Beta-band oscillations are a dominant feature in the sensorimotor system that associate to the motor function. We found that the movement-related postmovement beta synchronization (PMBS) over the contralateral sensorimotor cortex was positively correlated with the speed of a voluntary movement, but the movement-related beta desynchronization (MRBD) was not. Our results show a differential response of the PMBS and MRBD to the movement speed during voluntary movement.

Sensorimotor beta power reflects the precision-weighting afforded to sensory prediction errors

It has been proposed that accurate motor control relies on Bayesian inference that integrates sensory input with prior contextual knowledge (Bays and Wolpert, 2007; Körding and Wolpert, 2004; Wolpert et al., 1995). Recent evidence has suggested that modulations in beta power (∼12–30 Hz) measured over sensorimotor cortices using electroencephalography (EEG) may represent parameters of Bayesian inference. While the well characterised post-movement beta synchronisation has been shown to correlate with prediction error (H. Tan, Jenkinson, & Brown, 2014; Huiling Tan, Wade, & Brown, 2016), recent evidence suggests that beta power may also represent uncertainty measures (Tan et al., 2016; Tzagarakis et al., 2015). The current study aimed to measure the neurophysiological correlates of uncertainty mediating Bayesian updating during a visuomotor adaptation paradigm in healthy human participants. In particular, sensory uncertainty was directly modulated to measure its effect on sensorimotor beta power. Participant's behaviour was modelled using the Hierarchical Gaussian Filter (HGF) in order to extract the latent variables involved in learning actions required by the task and correlate these with the measured EEG. We found that sensorimotor beta power correlated with inverse uncertainty afforded to sensory prediction errors both prior to and following a movement. This suggests that sensorimotor beta oscillations may more readily represent relative uncertainty within the sensorimotor system rather than error. Neurophysiological models describing the generation of beta oscillations offer a potential mechanism by which this neural signature may encode latent uncertainty parameters. This is essential for understanding how the brain controls behaviour.

Magnitude of the post-movement beta synchronization correlates with the variability of the ankle torque production

Objectives During and after the completion of a motor task, an event-related desynchronization (ERD) and synchronization (ERS) – i.e., a decrease and increase of the 13–31 Hz spectral magnitude–are respectively recorded over the motor cortex (M1). The ERD is supposed to reflect M1 involvement to perform the motor task [1] , [2] while the ERS is supposed to reflect an active “top-down” cortical inhibition of the motor command [1] , [3] . Studies revealed that ERD/S are modulated with the force level [1] . However, it remains to know whether ERD/S are related to the task performance, reflecting force control. We investigated the relationship between the ERD/S and the accuracy and variability of the force production. Methods Eleven healthy participants performed 50 × 10-s isometric right plantar flexion contractions at 20% of their maximal torque. The ankle torque and the M1 EEG activity were recorded. After appropriate preprocessing, the absolute and variable errors (AE/VE) of the ankle torque, respectively reflecting accuracy and variability of the motor task and the ERD were computed during the holding force phase. The ERS was computed 1-s after the end of the contraction. All data were normally distributed. Pearson correlations between ERD/S and AE/VE were computed. Results No significant correlation was found between the ERD and VE (r2 = 0.11; P = 0.75) nor between the ERD and AE (r2 = 0.56; P = 0.07). The ERS significantly increased as the VE increased (r2 = 0.8; P Conclusion These results suggest that the ERD is not linked with fine motor control modulating accuracy and variability of force. However, the significant ERS-VE relationship suggests that the more variable is the force produced, the more M1 is deactivated, probably reflecting an increased inhibition of the motor command.

Age-related changes in post-movement beta synchronization during a selective inhibition task.

Post-movement beta synchronization (PMBS) modulations have been related to sensory reafferences after movement initiation and inhibitory processes after movement interruption. Although these processes have been separately studied in young and old adults, little is known about the age-related changes in PMBS during selective inhibitory control (i.e. stop a part of an action). The present study examines the age-related modulations of PMBS associated with sensory reafferences and inhibitory processes in selective inhibitory control. Young (n=17) and old (n=13) participants performed a switching task first engaging bimanual finger tapping then requiring to stop the left while maintaining the right unimanual tapping (i.e. selective inhibition) at an imperative stimulus. Age groups were compared on behavioral (mean, variability and percentage of errors of inter-tap interval during and after the switching) and electrophysiological (time-frequency and source estimations in the 14-30Hz beta frequency range) data time-locked on the imperative stimulus. Behaviorally, old adults showed larger variability and percentage of errors during the switching but performed as well as young adults after the switching. Electrophysiologically, PMBS significantly increased after the switching in the old compared to the young group within bilateral frontal and parietal areas. Our results show that the effort to maintain selective inhibition involves increased brain activation in old compared to young adults. The larger PMBS within frontal and parietal regions in old adults may reflect an age-related brain compensation enabling to efficiently maintain post-switching inhibition.

Post-Movement Beta Activity in Sensorimotor Cortex Indexes Confidence in the Estimations from Internal Models.

For optimal sensorimotor control, sensory feedback and feedforward estimation of a movement's sensory consequences should be weighted by the inverse of their corresponding uncertainties, which require recursive updating in a dynamic environment. We show that post-movement beta activity (13-30 Hz) over sensorimotor cortex in young healthy subjects indexes the evaluation of uncertainty in feedforward estimation. Our work contributes to the understanding of the function of beta oscillations in sensorimotor control, and provides further insight into how aberrant beta activity can contribute to the pathophysiology of movement disorders.

Post-switching beta synchronization reveals concomitant sensory reafferences and active inhibition processes

It is known that post-movement beta synchronization (PMBS) is involved both in active inhibition and in sensory reafferences processes. The aim of this study was examine the temporal and spatial dynamics of the PMBS involved during multi-limb coordination task. We investigated post-switching beta synchronization (assigned PMBS) using time-frequency and source estimations analyzes. Participants (n=17) initiated an auditory-paced bimanual tapping. After a 1500ms preparatory period, an imperative stimulus required to either selectively stop the left while maintaining the right unimanual tapping (Switch condition: SWIT) or to continue the bimanual tapping (Continue condition: CONT). PMBS significantly increased in SWIT compared to CONT with maximal difference within right central region in broad-band 14–30Hz and within left central region in restricted-band 22–26Hz. Source estimations localized these effects within right pre-frontal cortex and left parietal cortex, respectively. A negative correlation showed that participants with a low percentage of errors in SWIT had a large PMBS amplitude within right parietal and frontal cortices. This study shows for the first time simultaneous PMBS with distinct functions in different brain regions and frequency ranges. The left parietal PMBS restricted to 22–26Hz could reflect the sensory reafferences of the right hand tapping disrupted by the switching. In contrast, the right pre-frontal PMBS in a broad-band 14–30Hz is likely reflecting the active inhibition of the left hand stopped. Finally, correlations between behavioral performance and the magnitude of the PMBS suggest that beta oscillations can be viewed as a marker of successful active inhibition.

P395: Switching from bimanual to unimanual tapping reveals two distinct post-switching beta synchronization processes

P395: Switching from bimanual to unimanual tapping reveals two distinct post-switching beta synchronization processes

Motor cortex stimulation modulates defective central beta rhythms in patients with neuropathic pain

ObjectiveMotor cortex stimulation therapy (MCS) is increasingly used to control refractory neuropathic pain. Post-movement beta synchronization (PMBS) is defined as a sharp increase in beta-frequency electroencephalographic power following movement offset and may reflect sensorimotor cortex inhibition induced, at least in part, by cortical processing of movement-related sensory afferent inputs. PMBS pattern is then often altered in case of neuropathic pain. The main objective of the present study was to test the hypothesis that implanted MCS modulates PMBS in patients presenting with neuropathic pain. MethodsUsing a high-resolution, 128-electrode electroencephalographic system, we recorded and compared, before and during MCS, PMBS patterns during brisk, unilateral right and left index finger extension in 8 patients presenting with neuropathic pain. ResultsThe pre-operative PMBS patterns were altered in all cases. MCS increased the spatial distribution and amplitude of PMBS in most of cases and restored maximum-intensity of PMBS contralateral to the painful body side. These modifications appeared significantly correlated with the analgesic effect of MCS. ConclusionThis study provides evidence of central beta rhythms neuromodulation induced by MCS. SignificanceThe restoration by MCS of defective cortical inhibition in patients with neuropathic pain is evoked.

Intermittent theta burst stimulation over ipsilesional primary motor cortex of subacute ischemic stroke patients: A pilot study

BackgroundWe demonstrated that prolonged transcranial magnetic intermittent theta burst stimulation (iTBS, 1200pulses/session=iTBS1200) produces longer-lasting facilitation in corticospinal excitability than ordinary form of iTBS in healthy subjects. ObjectiveHere we show the safety and small-scale efficacy of iTBS1200 over ipsilesional primary motor cortex (M1) in subacute stroke patients. MethodsTwelve patients with first-time, subacute ischemic stroke of the middle cerebral artery were randomized into two groups that received 10 daily-sessions of either iTBS1200 or sham stimulation (n=6/group) over ipsilesional M1 hand region in addition to medical and rehabilitation treatments. The primary outcome measures were safety and tolerability. The secondary outcome measures included the National Institute of Health Stroke Scale (NIHSS), Upper Extremity Fugl-Meyer Test (UE-FMT), Action Research Arm Test (ARAT), active motor thresholds (aMTs)/motor-evoked potentials (MEPs) from the extensor carpi radialis (ECR), and magnetoencephalography on post-intervention day 1 and post-stroke day 60. ResultsiTBS or sham stimulation was well tolerated by all patients without seizures or significant adverse effects. Compared with the matched controls, the iTBS group showed measurable improvements in the NIHSS and the proximal UE-FMT scores on post-intervention day 1 and post-stroke day 60. Nevertheless, the hand ARAT scores, aMT and MEPs from the paretic ECR were not different between groups. Post-movement beta synchronization increased over iTBS-conditioned M1 on post-intervention day 1 in testable patients. ConclusionsRepetitive sessions of iTBS1200 over ipsilesional M1 of subacute stroke patients are safe and the potential benefits encourage a larger trial to determine the efficacy in stroke patients. (ClinicalTrials.gov: NCT-01323881).

Source Analysis of Beta-Synchronisation and Cortico-Muscular Coherence after Movement Termination Based on High Resolution Electroencephalography

We hypothesized that post-movement beta synchronization (PMBS) and cortico-muscular coherence (CMC) during movement termination relate to each other and have similar role in sensorimotor integration. We calculated the parameters and estimated the sources of these phenomena.We measured 64-channel EEG simultaneously with surface EMG of the right first dorsal interosseus muscle in 11 healthy volunteers. In Task1, subjects kept a medium-strength contraction continuously; in Task2, superimposed on this movement, they performed repetitive self-paced short contractions. In Task3 short contractions were executed alone. Time-frequency analysis of the EEG and CMC was performed with respect to the offset of brisk movements and averaged in each subject. Sources of PMBS and CMC were also calculated.High beta power in Task1, PMBS in Task2-3, and CMC in Task1-2 could be observed in the same individual frequency bands. While beta synchronization in Task1 and PMBS in Task2-3 appeared bilateral with contralateral predominance, CMC in Task1-2 was strictly a unilateral phenomenon; their main sources did not differ contralateral to the movement in the primary sensorimotor cortex in 7 of 11 subjects in Task1, and in 6 of 9 subjects in Task2. In Task2, CMC and PMBS had the same latency but their amplitudes did not correlate with each other. In Task2, weaker PMBS source was found bilaterally within the secondary sensory cortex, while the second source of CMC was detected in the premotor cortex, contralateral to the movement. In Task3, weaker sources of PMBS could be estimated in bilateral supplementary motor cortex and in the thalamus.PMBS and CMC appear simultaneously at the end of a phasic movement possibly suggesting similar antikinetic effects, but they may be separate processes with different active functions. Whereas PMBS seems to reset the supraspinal sensorimotor network, cortico-muscular coherence may represent the recalibration of cortico-motoneuronal and spinal systems.

Intermittent theta burst stimulation over primary motor cortex enhances movement-related beta synchronisation

Objective The objective of this study is to investigate how transcranial magnetic intermittent theta burst stimulation (iTBS) with a prolonged protocol affects human cortical excitability and movement-related oscillations. Methods Using motor-evoked potentials (MEPs) and movement-related magnetoencephalography (MEG), we assessed the changes of corticospinal excitability and cortical oscillations after iTBS with double the conventional stimulation time (1200 pulses, iTBS1200) over the primary motor cortex (M1) in 10 healthy subjects. Continuous TBS (cTBS1200) and sham stimulation served as controls. Results iTBS1200 facilitated MEPs evoked from the conditioned M1, while inhibiting MEPs from the contralateral M1 for 30 min. By contrast, cTBS1200 inhibited MEPs from the conditioned M1. Importantly, empirical mode decomposition-based MEG analysis showed that the amplitude of post-movement beta synchronisation (16–26 Hz) was significantly increased by iTBS1200 at the conditioned M1, but was suppressed at the nonconditioned M1. Alpha (8–13 Hz) and low gamma-ranged (35–45 Hz) rhythms were not notably affected. Movement kinetics remained consistent throughout. Conclusions TBS1200 modulated corticospinal excitability in parallel with the direction of conventional paradigms with modestly prolonged efficacy. Moreover, iTBS1200 increased post-movement beta synchronisation of the stimulated M1, and decreased that of the contralateral M1, probably through interhemispheric interaction. Significance Our results provide insight into the underlying mechanism of TBS and reinforce the connection between movement-related beta synchronisation and corticospinal output.

Disturbed post-movement beta synchronization in Wilson's disease with neurological manifestation

We analyzed the changes of post-movement beta synchronization (PMBS) of the electroencephalogram (EEG) in Wilson's disease with neurological manifestation. Our aim was to determine if PMBS in Wilson's disease is altered in a different way than in Parkinson's disease or in essential tremor. Our purpose was to find out whether the analysis of PMBS could help the diagnosis in ambiguous cases. Ten patients with neurological manifestation of Wilson's disease and ten controls performed self-paced movements with the dominant hand during EEG acquisition. Five electrodes above the sensorimotor cortex were selected for evaluation (C3, C1, Cz, C2, C4) as contralateral (C); contralateral medial (CM); medial (M); ipsilateral medial (IM); ipsilateral (I) relative to the dominant hand. Power and latency of PMBS were calculated by time resolved power spectral analysis with multitaper method. PMBS power in the C electrode position was significantly lower in patients than in controls, its contralateral preponderance disappeared in the patient group. In every location, latency of PMBS was significantly longer in the Wilson group compared to controls. More altered PMBS could be measured in patients with both basal ganglia and cerebellar involvements. Since decreased power of PMBS was observed in Parkinson's disease and increased latency in essential tremor, the combined change of PMBS can indicate pathology of different neural circuits and may help the diagnosis in challenging cases.

Post-movement beta synchronisation after complex prosaccade task

Objective Post-movement beta synchronisation (PMBS) has been described as an induced, localised increase of beta activity over the contralateral sensorimotor cortex after termination of voluntary limb movement. The aim of our study was to investigate whether ocular saccades also evoke movement related EEG changes. Methods Complex saccades were recorded in six healthy volunteers using electro-oculography. EEG power changes in the beta frequency band were measured before, during and after saccades. Results Significant increase of beta-power was observed over the frontocentral region of both hemispheres after the offset of the complex saccade task. The latency of ocular PMBS was about 1100 ms. Conclusions Ocular PMBS evoked by complex saccade task is similar to that of recorded after limb movements. Its presence over both hemispheres irrespective of the direction of saccades indicates bilateral activation of cortical areas connected with the execution and planning of ocular movements. Significance The present paper is the first report on eye-movement related post-movement beta synchronisation. Investigation of ocular PMBS can be used both for research and clinical purposes for the functional assessment of neuronal networks controlling eye movements.

Post-movement beta synchronization in subjects presenting with sensory deafferentation

Objective We studied the time course and location of post-movement beta synchronization (PMBS) in patients presenting with sensory deafferentation, in order to assess the hypothetical relationship between the PMBS and the cortical processing of movement-related somatosensory afferent inputs. Methods We used the event-related synchronization (ERS) method. EEG activity was recorded (via a 128-electrode system) during brisk, unilateral right and left index finger extension by 10 patients presenting with neuropathic pain related to sensory deafferentation. Intra- and post-movement changes in beta source power were calculated relative to pre-movement baseline activity. We compared the PMBS results for the painful and non-painful body sides. Furthermore, PMBS patterns in patients were compared with those in nine healthy volunteers. Results PMBS pattern related to the painful side had a spatial distribution, with an ipsilateral preponderance, significantly more restricted than PMBS pattern on the non-painful side and in the control group. There were no significant differences between patient PMBS patterns on the non-painful side and those in the control group. Conclusions Sensory deafferentation disrupts normal PMBS patterns. Significance This work provides additional arguments to the hypothesis supporting that the PMBS is influenced by movement-related somatosensory input processing.

Post-movement beta synchronization after kinesthetic illusion, active and passive movements

After the completion of a voluntary movement or in response to somatosensory stimulation, a short-lasting burst of beta oscillations (post movement beta ERS, beta rebound) can be observed. In the present study, we investigated if this is also true for the illusion of movements, induced by a vibration at 80 Hz on the biceps tendon. We compared the post-movement synchronization of EEG beta rhythms induced by active and passive movements and illusion in eight right-handed healthy subjects. As a result, a short-lasting post-movement beta ERS was present over motor areas after both active and passive and also after illusion of movement in all subjects. These results suggested a possible role of MI and the somatosensory cortex in the somatic perception of limb movement in humans.