Left Motor Research Articles

Cauda equina syndrome successfully treated with microdiscectomy and methylprednisolone therapy: A case report

Cauda equina syndrome (CES) caused by lumbar disc herniation is a rare neurosurgical emergency in young adults that requires immediate decompression. A surgical delay over 48 hours may result in irreversible ramifications, underscoring a crucial timeframe for managing this condition. We presented a 26-year-old man with lower limb weakness persisting for one week, accompanied with exacerbating bowel and bladder issues after massage. The patient had a history of low back pain and tingling sensations radiating to the left leg over the past year. His physical examination showed right motor strength of 5/4 and left motor strength of 5/3, with weakened bowel peristalsis, loose anal sphincter and saddle anaesthesia. A spinal MRI revealed protruded discs extending to the intervertebral levels of L4-L5 and L5-S1, implicating herniated discs as the likely cause of CES. He underwent a microdiscectomy with a posterior approach, and intravenous methylprednisolone was administered before the procedure. The next surgery demonstrated enhancements in motor strength, bowel and bladder function, and it also reduced pain. He was discharged with persistent tingling sensations in his both legs. We concluded that CES represents a critical neurosurgical emergency, which is diagnosed through clinical symptoms and neuroimaging. Rapid decompression and intravenous administration of methylprednisolone are associated with better prognosis.

Shared genetic architecture of cortical thickness alterations in major depressive disorder and schizophrenia

BackgroundMajor depressive disorder (MDD) and schizophrenia (SCZ) are heritable brain disorders characterized by alterations in cortical thickness. However, the shared genetic basis for cortical thickness changes in these disorders remains unclear. MethodsWe conducted a systematic literature search on cortical thickness in MDD and SCZ through PubMed and Web of Science. A coordinate-based meta-analysis was performed to identify cortical thickness changes. Additionally, utilizing summary statistics from the largest genome-wide association studies for depression (Ncase = 268,615, Ncontrol = 667,123) and SCZ (Ncase = 53,386, Ncontrol = 77,258), we explored shared genomic loci using conjunctional false discovery rate (conjFDR) analysis. Transcriptome-neuroimaging association analysis was then employed to identify shared genes associated with cortical thickness alterations, and enrichment analysis was finally carried out to elucidate the biological significance of these genes. ResultsOur search yielded 34 MDD (Ncase = 1621, Ncontrol = 1507) and 19 SCZ (Ncase = 1170, Ncontrol = 1043) neuroimaging studies for cortical thickness meta-analysis. Specific alterations in the left supplementary motor area were observed in MDD, while SCZ exhibited widespread reductions in various brain regions, particularly in the frontal and temporal areas. The conjFDR approach identified 357 genomic loci jointly associated with MDD and SCZ. Within these loci, 55 genes were found to be associated with cortical thickness alterations in both disorders. Enrichment analysis revealed their involvement in nervous system development, apoptosis, and cell communication. ConclusionThis study revealed the shared genetic architecture underlying cortical thickness alterations in MDD and SCZ, providing insights into common neurobiological pathways. The identified genes and pathways may serve as potential transdiagnostic markers, informing precision medicine approaches in psychiatric care.

Predicting tremor improvement after MRgFUS thalamotomy in essential tremor from preoperative spontaneous brain activity: A machine learning approach

Magnetic resonance-guided focused ultrasound surgery (MRgFUS) thalamotomy is an emerging technique for medication-refractory essential tremor (ET), but with variable outcomes. This study used pattern regression analysis to identify brain signatures predictive of tremor improvements. Fifty-four ET patients (mean age = 63.06 years, standard deviation (SD) = 10.55 years, 38 males) underwent unilateral MRgFUS thalamotomy and were scanned for resting-state functional magnetic resonance imaging (rs-fMRI). Seventy-four healthy controls (mean age = 58.09 years, SD = 10.30 years, 38 males) were recruited for comparison. Tremor responses at 12 months posttreatment were evaluated by the Clinical Rating Scale for Tremor. The fractional amplitude of low-frequency fluctuations (fALFF) was calculated from rs-fMRI data. Two-sample t-test was used to generate a disease-specific mask, within which Multivariate Kernel Ridge Regression analyses were conducted. Predicted and actual clinical scores were compared using Pearson’s correlation coefficient (r) and normalized mean squared error (Norm. MSE). Permutation test and leave-one-out strategy were applied for results validation. KRR identified fALFF patterns that significantly predicted the hand tremor improvement (r = 0.23, P = 0.025; Norm. MSE = 0.05, P = 0.026) and the postural tremor improvement (r = 0.28, P = 0.025; Norm. MSE = 0.06, P = 0.023), but not action tremor improvement. Lobule VI of right cerebellum (Cerebelum_6_R), right superior occipital gyrus (Occipital_Sup_R) and lobule X of vermis (Vermis_10) contributed most for hand tremor prediction (normalized weights (NW): 2.77%, 2.40%, 2.34%) while Vermis_10, left supplementary motor area (Supp_Motor_Area_L) and right hippocampus (Hippocampus_R) for postural tremor prediction (NW: 2.69%, 2.12%, 2.05%). The low contributing NW of the individual brain regions suggested that the fALFF pattern as a whole is an overall predicting feature. Preoperative fALFF pattern predicts tremor benefits induced by MRgFUS thalamotomy. ClinicalTrials.gov number: NCT04570046.

Investigating the interaction between EEG and fNIRS: A multimodal network analysis of brain connectivity

The brain is a complex system with functional and structural networks. Different neuroimaging methods have been developed to explore these networks, but each method has its own unique strengths and limitations, depending on the signals they measure. Combining techniques like electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) has gained interest, but understanding how the information derived from these modalities is related to each other remains an exciting open question. The multilayer network model has emerged as a promising approach to integrate different sources data. In this study, we investigated the hemodynamic and electrophysiological data captured by fNIRS and EEG to compare brain network topologies derived from each modality, examining how these topologies vary between resting state (RS) and task-related conditions. Additionally, we adopted the multilayer network model to integrate EEG and fNIRS data and evaluate the benefits of combining multiple modalities compared to using a single modality in capturing characteristic brain functioning.A small-world network structure was observed in the rest, right motor imagery, and left motor imagery tasks in both modalities. We found that EEG captures faster changes in neural activity, thus providing a more precise estimation of the timing of information transfer between brain regions in RS. fNIRS provides insights into the slower hemodynamic responses associated with longer-lasting and sustained neural processes in cognitive tasks. The multilayer approach outperformed unimodal analyses, offering a richer understanding of brain function. Complementarity between EEG and fNIRS was observed, particularly during tasks, as well as a certain level of redundancy and complementarity between the multimodal and the unimodal approach, which depends on the modality and the specific brain state. Overall, the results highlight differences in how EEG and fNIRS capture brain network topology in RS and tasks and emphasize the value of integrating multiple modalities for a comprehensive view of brain connectivity and function.

Central neurodegeneration in Kennedy’s disease accompanies peripheral motor dysfunction

Spinal and bulbar muscular atrophy (SBMA), or Kennedy’s disease (KD), is a rare hereditary neuromuscular disorder demonstrating commonalities with amyotrophic lateral sclerosis (ALS). The current study aimed to define functional and central nervous system abnormalities associated with SBMA pathology, their interaction, and to identify novel clinical markers for quantifying disease activity. 27 study participants (12 SBMA; 8 ALS; 7 Control) were recruited. SBMA patients underwent comprehensive motor and sensory functional assessments, and neurophysiological testing. All participants underwent whole-brain structural and diffusion MRI. SBMA patients demonstrated marked peripheral motor and sensory abnormalities across clinical assessments. Increased abnormalities on neurological examination were significantly associated with increased disease duration in SBMA patients (R2 = 0.85, p < 0.01). Widespread juxtacortical axonal degeneration of corticospinal white matter tracts were detected in SBMA patients (premotor; motor; somatosensory; p < 0.05), relative to controls. Increased axial diffusivity was significantly correlated with total neuropathy score in SBMA patients across left premotor (R2 = 0.59, p < 0.01), motor (R2 = 0.63, p < 0.01), and somatosensory (R2 = 0.61, p < 0.01) tracts. The present series has identified involvement of motor and sensory brain regions in SBMA, associated with disease duration and increasing severity of peripheral neuropathy. Quantification of annualized brain MRI together with Total Neuropathy Score may represent a novel approach for clinical monitoring.

Single-Trial Detection and Classification of Event-Related Optical Signals for a Brain-Computer Interface Application.

Event-related optical signals (EROS) measure fast modulations in the brain's optical properties related to neuronal activity. EROS offer a high spatial and temporal resolution and can be used for brain-computer interface (BCI) applications. However, the ability to classify single-trial EROS remains unexplored. This study evaluates the performance of neural network methods for single-trial classification of motor response-related EROS. EROS activity was obtained from a high-density recording montage covering the motor cortex during a two-choice reaction time task involving responses with the left or right hand. This study utilized a convolutional neural network (CNN) approach to extract spatiotemporal features from EROS data and perform classification of left and right motor responses. Subject-specific classifiers trained on EROS phase data outperformed those trained on intensity data, reaching an average single-trial classification accuracy of around 63%. Removing low-frequency noise from intensity data is critical for achieving discriminative classification results with this measure. Our results indicate that deep learning with high-spatial-resolution signals, such as EROS, can be successfully applied to single-trial classifications.

Differences in gray matter atrophy and functional connectivity between motor subtypes of Parkinson's disease.

Parkinson's disease (PD) patients with postural gait abnormalities exhibit poorer motor function scores, more severe non-motor symptoms, faster cognitive function deterioration, and a less favorable response to drugs and surgery compared to PD patients with tremor. This discrepancy is believed to be associated with more pronounced gray matter atrophy and abnormal functional connectivity. To investigate the distinctive pathological mechanisms between PD subtypes, we examined gray matter volume (GMV) and functional connectivity in patients with Parkinson's disease presenting with postural instability/gait difficulty (PD-PIGD), patients with tremor-dominant Parkinson's disease (PD-TD), and healthy controls. Voxel-based morphometry (VBM) of T1-weighted images was conducted to compare GMV among 64 PD-PIGD patients, 44 PD-TD patients, and 32 controls. Subsequently, functional connectivity within regions showing reduced GMV was compared across the groups. We analyzed whether differences among the groups were associated with clinical characteristics and neuroimaging biomarkers using partial correlation and binary logistic regression. Our comparison between PD-PIGD and PD-TD patients revealed a link between PD-PIGD and more extensive frontotemporal atrophy, potentially indicating increased basal ganglia activity accompanied by decreased cerebellum activity. Furthermore, in addition to the smaller GMV in the left middle temporal gyrus, the increased functional connectivity between this brain region and the right caudate was also the independent risk factor for PD-PIGD. In addition, we compared brain network connectivity between the PIGD and TD subtypes, using an independent component analysis (ICA). We found that Compared to PD-TD, PD-PIGD patients showed an enhanced sensorimotor network (SMN) around the left supplementary motor area. These findings suggest that severe gray matter atrophy and abnormal functional connectivity and brain networks may serve as pathophysiological mechanisms distinguishing PD-PIGD patients from other subtypes.

Human neural stem cells transplanted during the sequelae phase alleviate motor deficits in a rat model of cerebral palsy

AimsCerebral palsy (CP) is the most common physical disability in children, yet lacks an ideal animal model or effective treatment. This study aimed to develop a reliable CP model in neonatal rats and explore the effectiveness and underlying mechanisms of human neural stem cells (hNSCs) transplantation during the sequelae phase of CP. MethodsVasoconstrictor endothelin-1 (ET-1) was administered intracranially to the motor cortex and striatum of rats on postnatal day 5 to establish a CP model. hNSCs (5 × 105/5 μL) pretreated with hypoxia (5% O2 for 24 h) were transplanted near the infarct 3 weeks after ET-1 injury (the sequelae phase). The distribution and differentiation of hNSCs were observed after transplantation. Changes in neurotrophic factors, neurogenesis, angiogenesis, axonal plasticity, and motor function were analyzed. ResultsNeurobehavioral tests showed poor muscle strength and postural control in young ET-1 rats. Motor deficits of the left forelimb and gait abnormalities persisted into adulthood. Histopathological findings and MRI indicated the atrophy of the cortex, striatum, and adjacent corpus callosum in ET-1 rats. At 56 days after transplantation, hNSCs were widely distributed in the ipsilateral hemisphere, and differentiated into neurons, oligodendrocytes and astrocytes. Transplantation of hNSCs increased BDNF and VEGF expression, EdU+ cell number in the SVZ area, RECA-1+ vessel density and GAP-43 intensity around the lesion in ET-1 rats. The cylinder test revealed a significant increase in the left forelimb motor function from 28 days after transplantation, and the staircase and CatWalk tests showed improvements in fine motor function and gait parameters. ConclusionsIntracerebral injection of ET-1 modelled key functional and histopathological features of CP. hNSCs transplanted during the sequelae phase of CP resulted in long-term improvement in motor performance, possibly attributed to its capacity to stimulate neurotrophic factors, facilitate neurogenesis, angiogenesis, and promote axonal plasticity.

Neurophysiological Pathways of Unconscious Emotion Processing in Depression: Insights From a Simultaneous Electroencephalography–Functional Magnetic Resonance Imaging Measurement

BackgroundMajor depressive disorder (MDD) is characterized by strong emotional dysregulation. Mechanisms driving the negative affect in depression may be fast processes existing on an unconscious level. MethodsA priming task was conducted using simultaneous electroencephalography–functional magnetic resonance imaging measurement involving presentation of facial expressions (happy, sad, and neutral) to examine the neurophysiological pathway of biased unconscious emotion processing in MDD. Priming prior to a target emotion created unconscious (16.7-ms primer) and conscious (150-ms primer) trials. A large sample (N = 126) was recruited, containing healthy control participants (n = 66; 37 women) and participants with MDD (n = 60; 31 women). ResultsThe healthy control group showed a shorter reaction time in happy but not in sad or neutral trials compared with the MDD group. N170 amplitudes were lower in trials with unconscious than conscious primer presentation. N170 amplitudes correlated with cortical (right fusiform gyrus, right middle temporal gyrus, right inferior temporal gyrus, left supplementary motor area, right middle frontal gyrus) and subcortical brain regions (right amygdala). The strength of N170 and brain activity correlation increased when the stimulus was consciously presented. Presented emotions did not affect the correlation of N170 values and brain activity. ConclusionsOur findings show that MDD may exhibit biased emotion regulation abilities at a behavioral and neurophysiological level. Face-sensitive event-related potentials demonstrate a correlation with heightened brain activity in regions associated with both face recognition (fusiform gyrus) and emotion processing (amygdala). These findings are evident in both MDD and healthy control groups, with lower effect sizes in the MDD group indicating reduced emotion recognition and processing abilities.

“Doctor, What Would You do if You Were Me?” - A Survey of Physician Perspectives Toward Glioblastoma Resection

How maximal safe resection (MSR) of glioblastoma is implemented in the clinical setting remains understudied. Here, we utilized a survey-based approach to understand physician perspectives on this matter. Scenarios involving glioblastomas were presented to physicians who were asked to select from planned sub-total resection (STR), gross total resection (GTR), medical therapy only, or palliative care. Demographic, experience, and Likert scales of value assessment were collected. In the scenario involving a corpus callosum glioblastoma, 2.33% opted for GTR. For a right frontal glioblastoma, 91.7% opted for GTR. In contrast, only 30.8% chose GTR of a right motor strip glioblastoma (p< 0.001). When presented with a left motor strip glioblastoma, fewer respondents (12.7%,p < 0.001) opted for GTR. Physicians who placed a high value on preserving physical independence were more likely to forgo GTR for right motor glioblastomas (HR=0.068,95% CI:0.47-0.97,p=0.035), and physicians who placed a high value on their faith were more likely to opt for surgical treatments that differ from the general consensus, for instance opting for GTR of the corpus callosum glioblastoma (HR=4.18,95%CI:1.63-10.74,p=0.003). No other associations were found between the choice for GTR and other variables collected. Our results suggest that while maximal safe resection remains a guiding principle for glioblastoma resection, physician preference in terms of the extent of resection varies significantly as a function of tumor location and personal values.

Cortical Activation during Swallowing Exercise Tasks: an fNIRS Pilot Study.

This pilot study used functional near-infrared spectroscopy (fNIRS) to examine brain activity in selected regions of the left motor and sensory cortex while doing swallowing-related tasks. Specifically, differences in cortical activation during normal saliva swallows, effortful swallows, and tongue pressing were investigated. Nine healthy, right-handed adults (5 female, 4 male; Age: 22-30 years) were recruited. The tasks included were (1) normal saliva swallowing, (2) effortful saliva swallowing, and (3) lingual pressing against the palate. Each task was completed three times in a block, for a total of five blocks. Blocks were randomized and presented with set time intervals using PsychoPy. Motor activity was highest during effortful swallows, followed by normal swallows, and lingual presses. Activation in the sensory region was not significantly different across tasks; however, effortful swallows elicited the highest mean peak activation. Our findings suggest that fNIRS can be a viable imaging method used to examine differences in cortical activity in the context of swallowing. Its applicability in future dysphagia research should be explored.

Speech and neuroimaging effects following HiCommunication: a randomized controlled group intervention trial in Parkinson's disease.

Speech, voice and communication changes are common in Parkinson's disease. HiCommunication is a novel group intervention for speech and communication in Parkinson's disease based on principles driving neuroplasticity. In a randomized controlled trial, 95 participants with Parkinson's disease were allocated to HiCommunication or an active control intervention. Acoustic analysis was performed pre-, post- and six months after intervention. Intention-to-treat analyses with missing values imputed in linear multilevel models and complimentary per-protocol analyses were performed. The proportion of participants with a clinically relevant increase in the primary outcome measure of voice sound level was calculated. Resting-state functional MRI was performed pre- and post-intervention. Spectral dynamic causal modelling and the parametric empirical Bayes methods were applied to resting-state functional MRI data to describe effective connectivity changes in a speech-motor-related network of brain regions. From pre- to post-intervention, there were significant group-by-time interaction effects for the measures voice sound level in text reading (unstandardized b = 2.3, P = 0.003), voice sound level in monologue (unstandardized b = 2.1, P = 0.009), Acoustic Voice Quality Index (unstandardized b = -0.5, P = 0.016) and Harmonics-to-Noise Ratio (unstandardized b = 1.3, P = 0.014) post-intervention. For 59% of the participants, the increase in voice sound level after HiCommunication was clinically relevant. There were no sustained effects at the six-month follow-up. In the effective connectivity analysis, there was a significant decrease in inhibitory self-connectivity in the left supplementary motor area and increased connectivity from the right supplementary motor area to the left paracentral gyrus after HiCommunication compared to after the active control intervention. In conclusion, the HiCommunication intervention showed promising effects on voice sound level and voice quality in people with Parkinson's disease, motivating investigations of barriers and facilitators for implementation of the intervention in healthcare settings. Resting-state brain effective connectivity was altered following the intervention in areas implicated, possibly due to reorganization in brain networks.

Transcranial Magnetic Stimulation–Induced Plasticity Improving Cognitive Control in Obsessive-Compulsive Disorder, Part I: Clinical and Neuroimaging Outcomes From a Randomized Trial

BackgroundRepetitive transcranial magnetic stimulation (rTMS) is an emerging treatment for obsessive-compulsive disorder (OCD). The neurobiological mechanisms of rTMS in OCD have been incompletely characterized. We compared clinical outcomes and changes in task-based brain activation following 3 different rTMS protocols, all combined with exposure and response prevention. MethodsIn this 3-arm proof-of-concept randomized trial, 61 treatment-refractory adult patients with OCD received 16 sessions of rTMS immediately before exposure and response prevention over 8 weeks, with task-based functional magnetic resonance imaging scans and clinical assessments before and after treatment. Patients received high-frequency rTMS to the left dorsolateral prefrontal cortex (n = 19 [13 women/6 men]), high-frequency rTMS to the left pre-supplementary motor area (preSMA) (n = 23 [13 women/10 men]), or control rTMS to the vertex (n = 19 [13 women/6 men]). Changes in task-based functional magnetic resonance imaging activation before/after treatment were compared using both a Bayesian region of interest and a general linear model whole-brain approach. ResultsMean OCD symptom severity decreased significantly in all treatment groups (Δ = −10.836, p < .001, 95% CI −12.504 to −9.168), with no differences between groups. Response rate in the entire sample was 57.4%. The dorsolateral prefrontal cortex rTMS group showed decreased planning-related activation after treatment that was associated with greater symptom improvement. No group-level activation changes were observed for the preSMA and vertex rTMS groups. Participants in the preSMA group with greater symptom improvement showed decreased error-related activation, and symptom improvement in the vertex group was associated with increased inhibition-related activation. ConclusionsrTMS to preSMA and dorsolateral prefrontal cortex combined with exposure and response prevention led to activation decreases in targeted task networks in individuals showing greater symptom improvement, although we observed no differences in symptom reduction between groups.

Exploring visuospatial function neuroplasticity in elite speed skaters: a resting-state fMRI independent component analysis.

Limited research has been conducted on the neural mechanisms of visuospatial attention in closed skill sports. This research aimed to delve into the unique visuospatial attention abilities of skaters and elucidate the underlying neural mechanisms. This cross-sectional study employed an expert-novice paradigm, applying a purely data-driven approach to analyze and compare the resting-state networks (RSNs) associated with visuospatial attention in 15 elite skaters and 15 control subjects. From the 38 components identified by independent component analysis (ICA) algorithm, five RSNs were selected, including the dorsal attention network (DAN), left and right fronto-parietal network (FPN), somatomotor network (SMN) and visual network (VIS). Elite skaters exhibited heightened functional connectivity (FC) in the right angular gyrus and left precuneus within DAN, left fusiform gyrus within left FPN, right primary motor cortex within right FPN, left supplementary motor area within SMN, and right primary visual cortex within VIS compared to the control group. Conversely, skaters demonstrated diminished FC in the bilateral superior temporal gyrus within DAN and right prefrontal cortex within the right FPN. Statistical results demonstrated significant differences in RSNs related to visuospatial functions in a wide range of brain regions between elite skaters and controls. We further speculate that these variances could be attributable to alterations in visuospatial abilities resulting from years of devoted skating training. The findings of this study offer novel perspectives on the neural reorganization linked to motor training, contributing to an enriched comprehension of the neuroplasticity changes inherent in prolonged engagement in motor skill development.

Short-term antipsychotic treatment reduces functional connectivity of the striatum in first-episode drug-naïve early-onset schizophrenia

BackgroundThe striatum is thought to play a critical role in the pathophysiology and antipsychotic treatment of schizophrenia. Previous studies have revealed abnormal functional connectivity (FC) of the striatum in early-onset schizophrenia (EOS) patients. However, no prior studies have examined post-treatment changes of striatal FC in EOS patients. MethodsWe recruited 49 first-episode drug-naïve EOS patients to have resting-state functional magnetic resonance imaging scans at baseline and after 8 weeks of treatment with antipsychotics, along with baseline scanning of 34 healthy controls (HCs) for comparison purposes. We examined the FC values between each seed in striatal subregion and the rest of the brain. The Positive and Negative Syndrome Scale (PANSS) was applied to measure psychiatric symptoms in patients. ResultsCompared with HCs at baseline, EOS patients exhibited weaker FC of striatal subregions with several brain regions of the salience network and default mode network. Meanwhile, FC between the dorsal caudal putamen (DCP) and left supplementary motor area, as well as between the DCP and right postcentral gyrus, was negatively correlated with PANSS negative scores. Furthermore, after 8 weeks of treatment, EOS patients showed decreased FC between subregions of the putamen and the triangular part of inferior frontal gyrus, middle frontal gyrus, supramarginal gyrus and inferior parietal lobule. ConclusionsDecreased striatal FC is evident, even in the early stages of schizophrenia, and enhance our understanding of the neurodevelopmental abnormalities in schizophrenia. The findings also demonstrate that reduced striatal FC occurs after antipsychotic therapy, indicating that antipsychotic effects need to be accounted for when considering striatal FC abnormalities in schizophrenia.

Contingent magnetic variation and beta-band oscillations in sensorimotor temporal decision-making

The ability to accurately encode the temporal information of sensory events and hence to make prompt action is fundamental to humans’ prompt behavioral decision-making. Here we examined the ability of ensemble coding (averaging multiple inter-intervals in a sound sequence) and subsequent immediate reproduction of target duration at half, equal, or double that of the perceived mean interval in a sensorimotor loop. With magnetoencephalography (MEG), we found that the contingent magnetic variation (CMV) in the central scalp varied as a function of the averaging tasks, with a faster rate for buildup amplitudes and shorter peak latencies in the “half” condition as compared to the “double” condition. ERD (event-related desynchronization) -to-ERS (event-related synchronization) latency was shorter in the ”half” condition. A robust beta band (15–23 Hz) power suppression and recovery between the final tone and the action of key pressing was found for time reproduction. The beta modulation depth (i.e., the ERD-to-ERS power difference) was larger in motor areas than in primary auditory areas. Moreover, results of phase slope index (PSI) indicated that beta oscillations in the left supplementary motor area (SMA) led those in the right superior temporal gyrus (STG), showing SMA to STG directionality for the processing of sequential (temporal) auditory interval information. Our findings provide the first evidence to show that CMV and beta oscillations predict the coupling between perception and action in time averaging.

Cortical Mechanisms Underlying Effects of Repetitive Peripheral Magnetic Stimulation on Dynamic and Static Postural Control in Patients with Chronic Non-Specific Low Back Pain: A Double-Blind Randomized Clinical Trial.

Patients with chronic non-specific low back pain (CNLBP) often experience impaired postural control, contributing to pain recurrence. Although repetitive peripheral magnetic stimulation (rPMS) combined with core muscle training (CMT) could improve postural control, its neural mechanism remains unclear. This study aims to investigate the postural control-related cortical mechanism of the effect of rPMS on patients with CNLBP. This unicentric, prospective, randomized, double-blind, controlled trial was conducted in a public hospital from May to December 2023. A total of 40 patients (27 females and 13 males, mean age 29.38±7.72) with CNLBP were randomly assigned to either the rPMS group (real rPMS with CMT) or the sham-rPMS group (sham-rPMS with CMT) for 12 sessions over 4weeks. The rPMS was applied to the lumbar paravertebral multifidus muscle on the painful side. Pain and disability were quantified using the visual analog scale (VAS) and Oswestry dysfunction index (ODI) pre- and post-intervention. Furthermore, the sway area and velocity of the center of pressure (COP) were measured using a force platform. The cortical activities in 6 regions of interest during 4 tasks (standing with eyes open/closed on a stable/unstable plane) were recorded by functional near-infrared spectroscopy (fNIRS) pre- and post-intervention. The repeated measure ANOVA was applied for statistical analysis. Spearman's correlation was used to determine the relationships between variables. After the intervention, the rPMS group showed decreased pain intensity (p=0.001) and sway area (unstable eyes-closed task) (p=0.046) compared to the sham-rPMS group. Additionally, the rPMS group exhibited increased activation in left primary motor cortex (M1) (p=0.042) and reduced in left supplementary motor area (SMA) (p=0.045), whereas the sham-rPMS group showed no significant changes. The increased activation of left M1 was negatively correlated to the reduction of pain intensity (r=-0.537, p=0.018) and sway area (r=-0.500, p=0.029) under the static balancing task. Furthermore, there was a positive correlation between sway velocity and VAS (r=0.451, p=0.046) post-rPMS intervention. Repetitive peripheral magnetic stimulation combined with core muscle training demonstrated better analgesic effects and postural control improvements, compared to sham-stimulation. This may be attributed to the increased activation of the left primary motor cortex. The trial was registered on ClinicalTrials.gov (ChiCTR2300070943).

Comparing classic-onset corticobasal syndrome to speech/language-onset corticobasal syndrome

IntroductionPatients with classic-onset corticobasal syndrome (CBS) present with asymmetric limb apraxia and parkinsonism. We have, however, observed patients who initially present with speech and/or language (SL) problems and several years later develop CBS (i.e., SL-onset CBS). We aimed to compare clinical, neuroimaging and pathological characteristics of classic-onset CBS with SL-onset CBS. MethodsWe conducted a retrospective cohort study of 62 patients who met criteria for CBS (17 presented with classic-onset CBS and 45 had SL-onset CBS). We compared demographics, clinical characteristics, and grey and white matter volume loss with SPM12 between groups and assessed pathology and corticobasal degeneration (CBD) pathological lesion counts in patients who had died and undergone autopsy. ResultsMedian age at CBS diagnosis was 66.4 years in classic-onset CBS and 73.6 years in SL-onset CBS. Classic-onset CBS had higher frequencies of dystonia, myoclonus, and alien limb phenomenon, while SL-onset CBS had a higher frequency of vertical supranuclear gaze palsy. Both groups showed smaller frontoparietal volumes than controls, with SL-onset CBS having greater volume loss in the left supplementary motor area than classic-onset CBS. All three classic-onset CBS cases with autopsy (100 %) had CBD pathology while 8/21 of SL-onset CBS cases (38 %) had CBD. Pathological lesion burden (including astrocytic plaques) did not differ between classic-onset and SL-onset CBS. ConclusionClassic-onset and SL-onset CBS appear to be different syndromes, with the former being a more profuse motor syndrome. The more widespread volume loss in SL-onset CBS likely reflects longer disease course.

Reduced TMS-evoked EEG oscillatory activity in cortical motor regions in patients with post-COVID fatigue

ObjectivePersistent fatigue is a major symptom of the so-called ’long-COVID syndrome’, but the pathophysiological processes that cause it remain unclear.We hypothesized that fatigue after COVID-19 would be associated with altered cortical activity in premotor and motor regions. MethodsWe used transcranial magnetic stimulation combined with EEG (TMS-EEG) to explore the neural oscillatory activity of the left primary motor area (l-M1) and supplementary motor area (SMA) in a group of sixteen post-COVID patients complaining of lingering fatigue as compared to a sample of age-matched healthy controls. Perceived fatigue was assessed with the Fatigue Severity Scale (FSS) and Fatigue Rating Scale (FRS). ResultsPost-COVID patients showed a remarkable reduction of beta frequency in both areas. Correlation analysis exploring linear relation between neurophysiological and clinical measures revealed a significant inverse correlation between the individual level of beta oscillations evoked by TMS of SMA with the individual scores in the FRS (r(15) = -0.596; p = 0.012). ConclusionsPost-COVID fatigue is associated with a reduction of TMS-evoked beta oscillatory activity in SMA. SignificanceTMS-EEG could be used to identify early alterations of cortical oscillatory activity that could be related to the COVID impact in central fatigue.

Evaluating functional connectivity differences between DBS ON/OFF states in essential tremor

Deep brain stimulation (DBS) targeting the ventral intermediate (Vim) nucleus of the thalamus is an effective treatment for essential tremor (ET). We studied 15 ​ET patients undergoing DBS to a major input/output tract of the Vim, the dentato-rubro-thalamic tract (DRTt), using resting state functional MRI (rsfMRI) to evaluate connectivity differences between DBS ON and OFF and elucidate significant regions most influential in impacting tremor control and/or concomitant gait ataxia. Anatomical/functional 1.5T MRIs were acquired and replicated for each DBS state. Tremor severity and gait ataxia severity were scored with DBS ON at optimal stimulation parameters and immediately upon DBS OFF. Whole brain analysis was performed using dual regression analysis followed by randomized permutation testing for multiple correction comparison. Regions of interest (ROI) analysis was also performed. All 15 patients had tremor improvement between DBS ON/OFF (p ​< ​0.001). Whole brain analysis revealed significant connectivity changes between states in the left pre-central gyrus and left supplemental motor area. Group analysis of ROIs revealed that, with threshold p ​< ​0.05, in DBS ON vs. OFF both tremor duration and tremor improvement were significantly correlated to changes in connectivity. A sub-group analysis of patients with greater ataxia had significantly decreased functional connectivity between multiple ROIs in the cortex and cerebellum when DBS was ON compared to OFF. Stimulation of the DRTt and concordant improvement of tremor resulted in connectivity changes seen in multiple regions outside the motor network; when combined with both structural and electrophysiologic connectivity, this may help to serve as a biomarker to improve DBS targeting and possibly predict outcome.