Improving outcomes after stroke depends on understanding both the causes of initial function/impairment and the mechanisms of recovery. Recovery in patients with initially low function/high impairment is variable, suggesting the factors relating to initial function/impairment are different to the factors important for subsequent recovery. Here we aimed to determine the contribution of altered brain structure and function to initial severity and subsequent recovery of the upper limb post-stroke. The Nine-Hole Peg Test was recorded in week 1 and one-month post-stroke and used to divide 36 stroke patients (18 females, age: M = 66.56 years) into those with high/low initial function and high/low subsequent recovery. We determined differences in week 1 brain structure (Magnetic Resonance Imaging) and function (Magnetoencephalography, tactile stimulation) between high/low patients for both initial function and subsequent recovery. Lastly, we examined the relative contribution of changes in brain structure and function to recovery in patients with low levels of initial function. Low initial function and low subsequent recovery are related to lower sensorimotor β power and greater lesion-induced disconnection of contralateral [ipsilesional] white-matter motor projection connections. Moreover, differences in intra-hemispheric connectivity (structural and functional) are unique to initial motor function, while differences in inter-hemispheric connectivity (structural and functional) are unique to subsequent motor recovery. Function-related and recovery-related differences in brain function and structure after stroke are related, yet not identical. Separating out the factors that contribute to each process is key to identifying potential therapeutic targets for improving outcomes.

Neuroimaging studies have typically relied on rigorously controlled experimental paradigms to probe cognition, in which movement is restricted, primitive, an afterthought or merely used to indicate a subject's choice. Whilst powerful, these paradigms do not often resemble how we behave in everyday life, so a new generation of ecologically valid experiments are being developed. Magnetoencephalography (MEG) measures neural activity by sensing extracranial magnetic fields. It has recently been transformed from a large, static imaging modality to a wearable method where participants can move freely. This makes wearable MEG systems a prime candidate for naturalistic experiments going forward. However, these experiments will also require novel methods to capture and integrate information about behaviour executed during neuroimaging, and it is not yet clear how this could be achieved. Here, we use video recordings of multi-limb dance moves, processed with open-source machine learning methods, to automatically identify time windows of interest in concurrent, wearable MEG data. In a first step, we compare a traditional, block-designed analysis of limb movements, where the times of interest are based on stimulus presentation, to an analysis pipeline based on hidden Markov model states derived from the video telemetry. Next, we show that it is possible to identify discrete modes of neuronal activity related to specific limbs and body posture by processing the participants' choreographed movement in a dancing paradigm. This demonstrates the potential of combining video telemetry with mobile magnetoencephalography and other legacy imaging methods for future studies of complex and naturalistic behaviours.

A proportion of stroke survivors use their paretic arm less than might be expected based on their level of impairment. The resulting underuse of the paretic arm has a negative impact on participation in neurorehabilitation and functional independence. However, non-use remains poorly understood. One possibility is that prioritising the non-paretic arm reflects a habit, despite residual functional capacity in the paretic arm. 30 chronic stroke survivors (Mean Fugl Meyer Upper Limb Score: 28.9 ± 11.3) participated in a simplified version of the forced response paradigm, which reliably identifies the presence of a habit. Participants were asked to choose which arm to use to maximise points scored during a reaching task. During half of the trials, the presumed habit of using the non-paretic arm yielded more points, whereas in the other half using the non-paretic arm incurred a loss of points. Participants completed two versions of this task, once with unlimited response time available and once without. Participants scored fewer points in the limited response condition compared to the unlimited response conditions. This difference was driven by a selective increase in the use of the non-paretic arm in trials where the paretic arm yielded more points. The results were not mediated by former hand dominance. Our results demonstrate that not using the non-paretic arm may reflect a habit response that is more readily triggered in demanding (e.g. time-limited) situations. This may explain why successful neurorehabilitation does not always result in a more functionally useful arm. Our results pave the way for targeted interventions such as habit breaking techniques to be included in clinical practise.

A central challenge in movement neuroscience is developing methods for non-invasive spatiotemporal imaging of brain activity during natural, whole-body movement. We test the utility of a new brain imaging modality, optically pumped magnetoencephalography (OP-MEG), as an instrument to study the spatiotemporal dynamics of human walking. Specifically, we ask whether known physiological signals can be recovered during discrete steps involving large-scale, whole-body translation. Our findings show that by using OP-MEG, we can image the brain during large-scale, natural movements. We provide proof-of-principle evidence for movement-related changes in beta band activity during stepping vs. standing, which are source-localized to the sensorimotor cortex. This work supports the significant potential of the OP-MEG modality for addressing fundamental questions in human gait research relevant to both the physiological and pathological mechanisms of walking.

The mechanisms underpinning the stopping of muscle contractions and relaxations during action inhibition remain unclear. Central stop commands may be targeted and act on task-active muscles only, or instead be global, acting on task-passive muscles as well. We addressed this question in three stop signal task experiments with human participants (n = 54; 18 male, 36 female). While maintaining baseline force levels (10% MVC) in both index fingers, Go signals required participants to increase or decrease this force in the task-active finger (Task-active Contract vs Task-active Relax) while keeping activity in the task-passive muscle constant. On 30% of trials, delayed stop signals instructed participants to stop the task-active responses. Stop-related activity was detected in task-active muscles at the single trial level, using electromyography (EMG), and used to determine whether stop-related activity was also present in task-passive muscles. We found that stop commands act on both task-active and task-passive muscles, suggesting global control. This global control was furthermore muscle state specific, by decreasing muscle activity when stopping contractions and increasing muscle activity when stopping relaxations. However, stopping muscle contractions involved more sustained suppression of muscle activity in task-active than taskpassive muscles, suggesting additional targeted control. This was not the case when stopping muscle relaxations, which only showed evidence of global control. Our results may explain how complex, real-world actions are inhibited. Global stop commands that are sensitive to muscle state may rapidly adjust muscle activity across the body, with additional control targeted to contracting, task-active muscles.

Neural dynamics at the laminar level are critical components of cortical computations, but in humans, non-invasive methods to study these dynamics have been limited to coarse distinctions between deep and superficial layers. Here, we demonstrate that high-precision magnetoencephalography (hpMEG) can achieve laminar inference by localizing sources across all six cortical laminae. Using a multilayer source reconstruction approach, we systematically assess the limits of hpMEG’s depth resolution, and show that laminar precision is achievable under optimal signal-to-noise ratios and co-registration accuracy. Our simulations reveal that accurate source reconstruction depends critically on aligning dipole orientations with the underlying cortical columnar structure, and that regional variations in cortical anatomy influence reconstruction fidelity. These findings position hpMEG as a powerful tool for investigating laminar-specific neural dynamics in cognition and behavior, and offer new opportunities to bridge invasive electrophysiology and human neuroimaging. ### Competing Interest Statement The authors have declared no competing interest. European Research Council, https://ror.org/0472cxd90, ERC-CoG 864550

Introduction There is currently insufficient high-quality evidence to make general recommendations about high-dose high-intensity upper-limb rehabilitation programmes. Here we describe a randomised controlled trial that will determine the efficacy of two forms of high-dose, high-intensity upper-limb rehabilitation provided in a rehabilitation unit setting.Methods and analysis Patients with moderate upper-limb impairment (n=105, at least 6 months after stroke) will be randomised to either (1) high-dose high-intensity conventional upper-limb rehabilitation, (2) high-dose high-intensity virtual reality-based upper-limb rehabilitation and (3) usual care (a waiting list control group). Groups 1 and 2 will receive a minimum of 45 hours of active time on task over 3 weeks. Outcome measures will be collected at (T1) baseline; (T2) immediately post intervention and (T3) 3 months after the intervention has finished. The primary outcome measure will be the Fugl-Meyer Upper Extremity Assessment at 3 months after the intervention. Secondary outcome measures will be clinical, kinematic and neurophysiological using transcranial magnetic stimulation and electroencephalography. Explanatory measures will include MRI-based markers for integrity of the corticospinal tract, dorsal column-medial lemniscal pathway, grey and white matter and lesion load. The aim is to detect a difference of 7.25 points on the Fugl-Meyer Upper Extremity Assessment between each treatment group and the waitlist control group, with a power of 0.9 and significance of 0.025 (to account for two primary analyses). Analysis of change in the primary and secondary outcome measures will be performed using mulitple regression analysis.Ethics and dissemination The study protocol (V.1) has been approved by the Wales Research Ethics Committee 2 Cardiff (Rec reference: 22/WA/0065) on 15 March 2022. All recruited participants will provide informed consent. Trial results will be disseminated through peer-reviewed publications, presentations at major stroke/neurorehabilitation conferences and outreach to relevant stakeholder communities.Trial registration number NCT05527262.

Transcranial electrical stimulation (tES) has gained substantial momentum as a research and therapeutic tool; however, it suffers from challenges related to reproducibility and quality assessment due to the absence of standardized reporting practices. Here we aim to develop a comprehensive and consensus-based checklist for conducting and reporting tES studies to enhance the quality of research and reports. In this Consensus Statement, we used a Delphi approach conducted across three rounds and involving 38 experts to identify crucial elements required to report in tES studies. This consensus-driven approach included the evaluation of the interquartile deviation (>1.00), the percentage of positive responses (above 60

Stroke frequently results in long-term upper limb (UL) motor impairments, limiting independence and quality of life. Accurate prediction of recovery trajectories is essential for personalizing rehabilitation strategies. While structural brain metrics such as corticospinal tract (CST) integrity have been widely studied, they incompletely explain motor outcome variability. Functional brain activity, quantified by sensorimotor activity in the beta (β) frequency range has emerged as a promising biomarker of motor system integrity and plasticity potential. This study assessed in 30 acute stroke survivors and 26 healthy controls how combining functional and structural metrics of brain function relates to initial motor severity and subsequent recovery, using clinical MRI/CT and electroencephalography during passive finger movement and rest. Structurally, grey and white matter damage were associated with initial severity. No associations with recovery were found for structural metrics alone. Functionally, β-activity in response to passive movement, and resting state activity were related to recovery, independent of initial impairment. Multivariate regression revealed that combining initial severity, structural information (CST damage) and brain function (sensorimotor β activity) provided the most accurate prediction of both global and UL-specific recovery (R2 = 80.1% and 74.3%, respectively). These findings underscore the importance of integrating functional and structural neural markers for improved stroke outcome prediction. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The study and CZ were supported by Brain Research UK (201718-13). L.C.M. was supported by the Medical Research Council (MR/N013867/1). This work was supported by a Senior Research Fellowship to Charlotte J Stagg by the Wellcome Trust (224430/Z/21/Z). This research was supported by the NIHR Oxford Health Biomedical Research Centre (NIHR203316). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. The Centre for Integrative Neuroimaging (203139/Z/16/Z and 203139/A/16/Z) and the Centre for Human Neuroimaging (203147/Z/16/Z) were supported by core funding from the Wellcome Trust. For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Research Ethics Committee of the University College London and the NHS Research Ethics Committee (London - Surrey Research Ethics Committee) approved the study protocol (20/LO/0520), and all subjects provided written informed consent. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.

Non-invasive spatiotemporal imaging of brain activity during large-scale, whole body movement is a significant methodological challenge for the field of movement neuroscience. Here, we present a dataset recorded using a new imaging modality – optically-pumped magnetoencephalography (OP-MEG) – to record brain activity during human stepping. Participants (n=3) performed a visually guided stepping task requiring precise foot placement while dual-axis and triaxial OP-MEG and leg muscle activity (electromyography, EMG) were recorded. The dataset also includes a structural MRI for each participant and foot kinematics. This multimodal dataset offers a resource for methodological development and testing for OPM data (e.g., movement-related interference rejection), within-subject analyses, and exploratory analyses to generate hypotheses for further work on the neural control of human stepping.

Introduction:There is a profound lack of electrophysiological data from the cerebellum in humans, as compared to animals, because it is difficult to record cerebellar activity non-invasively using magnetoencephalography (MEG) or electroencephalography (EEG). Recent developments in wearable MEG sensors hold potential to overcome this limitation, as they allow the placement of sensors closer to the cerebellum. Methods:We leveraged the development of wearable optically pumped magnetometers to record on-scalp MEG (OP-MEG) during an established cerebellar learning paradigm-eyeblink conditioning. In four healthy human adults, we first validated that OP-MEG can reliably detect cerebellar responses by examining responses to an air puff stimulus. Results:Significant responses were observed in sensors positioned over the cerebellar region in all four adults in response to the air puff. We then indirectly tested the hypothesis that these responses reflect the population-level spiking activity of Purkinje cells. The air-puff-evoked responses diminished during the acquisition of conditioned responses, corresponding with previously observed changes in Purkinje cell activity in animals. Additionally, in three out of four participants, we observed a cerebellar evoked response just prior to the peak of the conditioned blink, resembling learning-associated shifts in Purkinje cell response latencies. Discussion:This study demonstrates that OP-MEG is a viable method for recording cerebellar activity in humans. By bridging invasive animal recordings with non-invasive human neuroimaging, these findings provide further evidence of the cerebellum's role in human learning.

Low-intensity Transcranial Ultrasonic Stimulation (TUS) is a non-invasive brain stimulation technique enabling cortical and deep brain targeting with unprecedented spatial accuracy. Given the high rate of adoption by new users with varying levels of expertise and interdisciplinary backgrounds, practical guidelines are needed to ensure state-of-the-art TUS application and reproducible outcomes. Therefore, the International Transcranial Ultrasonic Stimulation Safety and Standards (ITRUSST) consortium has formed a subcommittee, endorsed by the International Federation of Clinical Neurophysiology (IFCN), to develop recommendations for best practice in TUS applications in humans. The practical guide presented here provides a brief introduction into ultrasound physics and sonication parameters. It explains the requirements of TUS lab equipment and transducer selection and discusses experimental design and procedures alongside potential confounds and control conditions. Finally, the guide elaborates on essential steps of application planning for stimulation safety and efficacy, as well as considerations when combining TUS with neuroimaging, electrophysiology, or other brain stimulation techniques. We hope that this practical guide to TUS will assist both novice and experienced users in planning and conducting high-quality studies and provide a solid foundation for further advancements in this promising field.

Focused ultrasound spinal cord neuromodulation studies have demonstrated spinal cord neuromodulation in small animals. The safe and efficacious translation of these approaches to human scale requires an understanding of ultrasound propagation and heat deposition within the human spine. To address this, combined acoustic and thermal modelling was used to assess the pressure and heat distributions produced by a 500 kHz source focused to the C5/C6 level of the cervical spine via two approaches a) the posterior acoustic window between vertebral posterior arches, or b) the lateral intervertebral foramen from which the C6 spinal nerve exits. Pulse trains of 150 0.1 s pulses with a pulse repetition frequency of 0.33 Hz and free-field spatial peak pulse-averaged intensity of 10 W/cm^2 were simulated for the CT volumes of four subjects and for $\pm$10 mm translational and $\pm$10{\deg} rotational source positioning errors. Target pressures ranged between 20% and 70% of free-field spatial peak pressures with the posterior approach, and 20% and 100% with the lateral approach. When the source was optimally positioned with the posterior approach, peak spine heating values were below 1{\deg}C, but source mis-positioning resulted in bone heating up to 4{\deg}C. Heating with the lateral approach did not exceed 2{\deg}C within the mispositioning range. There were substantial inter-subject differences in target pressures and peak heating values. Target pressure varied three to four-fold between subjects, depending on approach, while peak heating varied approximately two-fold between subjects. This results in a near ten-fold range in the target pressure achieved per degree of peak heating between subjects. This highlights the importance of developing trans-spine ultrasound simulation software for the assurance of subject-specific safety and efficacy of focused ultrasound spinal cord therapies.

Voluntary human movement relies on interactions between the spinal cord, brain, and sensory afferents. The integrative function of the spinal cord has proven particularly difficult to study directly and non-invasively in humans due to challenges in measuring spinal cord activity. Investigations of sensorimotor integration often rely on cortico-muscular coupling, which can capture interactions between the brain and muscle, but cannot reveal how the spinal cord mediates this communication. Here, we introduce a system for direct, non-invasive imaging of concurrent brain and cervical spinal cord activity in humans using optically-pumped magnetometers (OPMs). We used this system to study endogenous interactions between the brain, spinal cord, and muscle involved in sensorimotor control during simple maintained contraction. Participants ( n =3) performed a hand contraction with real-time visual feedback while we recorded brain and spinal cord activity using OPMs and muscle activity using EMG. We first identify the part of the spinal cord exhibiting a peak in estimated current flow in the cervical region during contraction. We then demonstrate that rhythmic activity in the spinal cord exhibits significant coupling with both brain and muscle activity in the 5-35 Hz frequency range. These findings evidence the possibility of concurrent spatio-temporal imaging along the entire neuro-axis. ### Competing Interest Statement The authors have declared no competing interest.

Abstract Background Stroke survivors can exhibit a mismatch between the actual motor ability of their affected upper limb and how much they use it in daily life. The resulting non-use of the affected upper limb has a negative impact on participation in neurorehabilitation and functional independence. The factors leading to non-use of the affected upper limb are poorly understood. One possibility is that non-use comes about through inappropriately low confidence in their own upper limb motor abilities. Objective We asked whether chronic stroke survivors underestimate the motor ability of their affected upper limb. Methods 20 chronic stroke survivors (Mean FM: 28.2 ± 10.5) completed a 2D reaching task using an exoskeleton robot. Target sizes were individually altered to ensure success rates were similar for both upper limbs. Prior to each reaching movement, participants rated their confidence about successfully hitting the target (estimated upper limb motor ability). Results Confidence ratings were significantly lower for the affected upper limb (estimated ability), even though it was equally successful in the reaching task in comparison to the less affected upper limb (actual ability). Furthermore, confidence ratings did not correlate with level of impairment. Conclusions Our results demonstrate that chronic stroke survivors can underestimate the actual motor abilities of their affected upper limb, independent of impairment level. Low confidence in affected upper limb motor abilities should be considered as a therapeutic target to increase the incorporation of the affected upper limb into activities of daily living.

The spinal cord and its interactions with the brain are fundamental for movement control and somatosensation. However, brain and spinal cord electrophysiology in humans have largely been treated as distinct enterprises, in part due to the relative inaccessibility of the spinal cord. Consequently, there is a dearth of knowledge on human spinal electrophysiology, including the multiple pathologies of the central nervous system that affect the spinal cord as well as the brain. Here we exploit recent advances in the development of wearable optically pumped magnetometers (OPMs) which can be flexibly arranged to provide coverage of both the spinal cord and the brain concurrently in unconstrained environments. Our system for magnetospinoencephalography (MSEG) measures both spinal and cortical signals simultaneously by employing a custom-made spinal scanning cast. We evidence the utility of such a system by recording simultaneous spinal and cortical evoked responses to median nerve stimulation, demonstrating the novel ability for concurrent non-invasive millisecond imaging of brain and spinal cord.