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1.
Elife ; 122024 Jun 06.
Article in English | MEDLINE | ID: mdl-38842277

ABSTRACT

Flexible responses to sensory stimuli based on changing rules are critical for adapting to a dynamic environment. However, it remains unclear how the brain encodes and uses rule information to guide behavior. Here, we made single-unit recordings while head-fixed mice performed a cross-modal sensory selection task where they switched between two rules: licking in response to tactile stimuli while rejecting visual stimuli, or vice versa. Along a cortical sensorimotor processing stream including the primary (S1) and secondary (S2) somatosensory areas, and the medial (MM) and anterolateral (ALM) motor areas, single-neuron activity distinguished between the two rules both prior to and in response to the tactile stimulus. We hypothesized that neural populations in these areas would show rule-dependent preparatory states, which would shape the subsequent sensory processing and behavior. This hypothesis was supported for the motor cortical areas (MM and ALM) by findings that (1) the current task rule could be decoded from pre-stimulus population activity; (2) neural subspaces containing the population activity differed between the two rules; and (3) optogenetic disruption of pre-stimulus states impaired task performance. Our findings indicate that flexible action selection in response to sensory input can occur via configuration of preparatory states in the motor cortex.


Subject(s)
Motor Cortex , Animals , Mice , Motor Cortex/physiology , Male , Somatosensory Cortex/physiology , Neurons/physiology , Female , Optogenetics , Behavior, Animal/physiology
2.
Sci Rep ; 14(1): 13057, 2024 06 06.
Article in English | MEDLINE | ID: mdl-38844650

ABSTRACT

Combined action observation and motor imagery (AOMI) facilitates corticospinal excitability (CSE) and may potentially induce plastic-like changes in the brain in a similar manner to physical practice. This study used transcranial magnetic stimulation (TMS) to explore changes in CSE for AOMI of coordinative lower-limb actions. Twenty-four healthy adults completed two baseline (BLH, BLNH) and three AOMI conditions, where they observed a knee extension while simultaneously imagining the same action (AOMICONG), plantarflexion (AOMICOOR-FUNC), or dorsiflexion (AOMICOOR-MOVE). Motor evoked potential (MEP) amplitudes were recorded as a marker of CSE for all conditions from two knee extensor, one dorsi flexor, and two plantar flexor muscles following TMS to the right leg representation of the left primary motor cortex. A main effect for experimental condition was reported for all three muscle groups. MEP amplitudes were significantly greater in the AOMICONG condition compared to the BLNH condition (p = .04) for the knee extensors, AOMICOOR-FUNC condition compared to the BLH condition (p = .03) for the plantar flexors, and AOMICOOR-MOVE condition compared to the two baseline conditions for the dorsi flexors (ps ≤ .01). The study findings support the notion that changes in CSE are driven by the imagined actions during coordinative AOMI.


Subject(s)
Evoked Potentials, Motor , Imagination , Lower Extremity , Motor Cortex , Muscle, Skeletal , Pyramidal Tracts , Transcranial Magnetic Stimulation , Humans , Male , Female , Evoked Potentials, Motor/physiology , Adult , Motor Cortex/physiology , Imagination/physiology , Young Adult , Pyramidal Tracts/physiology , Lower Extremity/physiology , Muscle, Skeletal/physiology , Electromyography
3.
Cereb Cortex ; 34(6)2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38836408

ABSTRACT

Sense of touch is essential for our interactions with external objects and fine control of hand actions. Despite extensive research on human somatosensory processing, it is still elusive how involved brain regions interact as a dynamic network in processing tactile information. Few studies probed temporal dynamics of somatosensory information flow and reported inconsistent results. Here, we examined cortical somatosensory processing through magnetic source imaging and cortico-cortical coupling dynamics. We recorded magnetoencephalography signals from typically developing children during unilateral pneumatic stimulation. Neural activities underlying somatosensory evoked fields were mapped with dynamic statistical parametric mapping, assessed with spatiotemporal activation analysis, and modeled by Granger causality. Unilateral pneumatic stimulation evoked prominent and consistent activations in the contralateral primary and secondary somatosensory areas but weaker and less consistent activations in the ipsilateral primary and secondary somatosensory areas. Activations in the contralateral primary motor cortex and supramarginal gyrus were also consistently observed. Spatiotemporal activation and Granger causality analysis revealed initial serial information flow from contralateral primary to supramarginal gyrus, contralateral primary motor cortex, and contralateral secondary and later dynamic and parallel information flows between the consistently activated contralateral cortical areas. Our study reveals the spatiotemporal dynamics of cortical somatosensory processing in the normal developing brain.


Subject(s)
Magnetoencephalography , Somatosensory Cortex , Humans , Male , Somatosensory Cortex/physiology , Somatosensory Cortex/growth & development , Female , Child , Evoked Potentials, Somatosensory/physiology , Brain Mapping , Touch Perception/physiology , Child Development/physiology , Magnetic Resonance Imaging , Nerve Net/physiology , Physical Stimulation , Motor Cortex/physiology , Motor Cortex/growth & development
4.
Cereb Cortex ; 34(5)2024 May 02.
Article in English | MEDLINE | ID: mdl-38715407

ABSTRACT

Facial palsy can result in a serious complication known as facial synkinesis, causing both physical and psychological harm to the patients. There is growing evidence that patients with facial synkinesis have brain abnormalities, but the brain mechanisms and underlying imaging biomarkers remain unclear. Here, we employed functional magnetic resonance imaging (fMRI) to investigate brain function in 31 unilateral post facial palsy synkinesis patients and 25 healthy controls during different facial expression movements and at rest. Combining surface-based mass-univariate analysis and multivariate pattern analysis, we identified diffused activation and intrinsic connection patterns in the primary motor cortex and the somatosensory cortex on the patient's affected side. Further, we classified post facial palsy synkinesis patients from healthy subjects with favorable accuracy using the support vector machine based on both task-related and resting-state functional magnetic resonance imaging data. Together, these findings indicate the potential of the identified functional reorganizations to serve as neuroimaging biomarkers for facial synkinesis diagnosis.


Subject(s)
Facial Paralysis , Magnetic Resonance Imaging , Synkinesis , Humans , Magnetic Resonance Imaging/methods , Facial Paralysis/physiopathology , Facial Paralysis/diagnostic imaging , Facial Paralysis/complications , Male , Female , Synkinesis/physiopathology , Adult , Middle Aged , Young Adult , Facial Expression , Biomarkers , Motor Cortex/physiopathology , Motor Cortex/diagnostic imaging , Brain Mapping , Somatosensory Cortex/diagnostic imaging , Somatosensory Cortex/physiopathology , Brain/diagnostic imaging , Brain/physiopathology , Support Vector Machine
5.
Int Rev Neurobiol ; 176: 87-118, 2024.
Article in English | MEDLINE | ID: mdl-38802184

ABSTRACT

This chapter describes the role of neurophysiological techniques in diagnosing and monitoring amyotrophic lateral sclerosis (ALS). Despite many advances, electromyography (EMG) remains a keystone investigation from which to build support for a diagnosis of ALS, demonstrating the pathophysiological processes of motor unit hyperexcitability, denervation and reinnervation. We consider development of the different diagnostic criteria and the role of EMG therein. While not formally recognised by established diagnostic criteria, we discuss the pioneering studies that have demonstrated the diagnostic potential of transcranial magnetic stimulation (TMS) of the motor cortex and highlight the growing evidence for TMS in the diagnostic process. Finally, accurately monitoring disease progression is crucial for the successful implementation of clinical trials. Neurophysiological measures of disease state have been incorporated into clinical trials for over 20 years and we review prominent techniques for assessing disease progression.


Subject(s)
Amyotrophic Lateral Sclerosis , Electromyography , Neurophysiology , Transcranial Magnetic Stimulation , Amyotrophic Lateral Sclerosis/diagnosis , Amyotrophic Lateral Sclerosis/physiopathology , Humans , Transcranial Magnetic Stimulation/methods , Electromyography/methods , Neurophysiology/methods , Disease Progression , Motor Cortex/physiopathology
6.
Open Biol ; 14(5): 240018, 2024 May.
Article in English | MEDLINE | ID: mdl-38745463

ABSTRACT

The neuronal cell adhesion molecule contactin-4 (CNTN4) is genetically associated with autism spectrum disorder (ASD) and other psychiatric disorders. Cntn4-deficient mouse models have previously shown that CNTN4 plays important roles in axon guidance and synaptic plasticity in the hippocampus. However, the pathogenesis and functional role of CNTN4 in the cortex has not yet been investigated. Our study found a reduction in cortical thickness in the motor cortex of Cntn4 -/- mice, but cortical cell migration and differentiation were unaffected. Significant morphological changes were observed in neurons in the M1 region of the motor cortex, indicating that CNTN4 is also involved in the morphology and spine density of neurons in the motor cortex. Furthermore, mass spectrometry analysis identified an interaction partner for CNTN4, confirming an interaction between CNTN4 and amyloid-precursor protein (APP). Knockout human cells for CNTN4 and/or APP revealed a relationship between CNTN4 and APP. This study demonstrates that CNTN4 contributes to cortical development and that binding and interplay with APP controls neural elongation. This is an important finding for understanding the physiological function of APP, a key protein for Alzheimer's disease. The binding between CNTN4 and APP, which is involved in neurodevelopment, is essential for healthy nerve outgrowth.


Subject(s)
Amyloid beta-Protein Precursor , Contactins , Mice, Knockout , Neurons , Animals , Mice , Amyloid beta-Protein Precursor/metabolism , Amyloid beta-Protein Precursor/genetics , Humans , Contactins/metabolism , Contactins/genetics , Neurons/metabolism , Motor Cortex/metabolism , Protein Binding , Cell Movement
7.
PLoS One ; 19(5): e0302989, 2024.
Article in English | MEDLINE | ID: mdl-38753604

ABSTRACT

Multiple sensorimotor loops converge in the motor cortex to create an adaptable system capable of context-specific sensorimotor control. Afferent inhibition provides a non-invasive tool to investigate the substrates by which procedural and cognitive control processes interact to shape motor corticospinal projections. Varying the transcranial magnetic stimulation properties during afferent inhibition can probe specific sensorimotor circuits that contribute to short- and long-latency periods of inhibition in response to the peripheral stimulation. The current study used short- (SAI) and long-latency (LAI) afferent inhibition to probe the influence of verbal and spatial working memory load on the specific sensorimotor circuits recruited by posterior-anterior (PA) and anterior-posterior (AP) TMS-induced current. Participants completed two sessions where SAI and LAI were assessed during the short-term maintenance of two- or six-item sets of letters (verbal) or stimulus locations (spatial). The only difference between the sessions was the direction of the induced current. PA SAI decreased as the verbal working memory load increased. In contrast, AP SAI was not modulated by verbal working memory load. Visuospatial working memory load did not affect PA or AP SAI. Neither PA LAI nor AP LAI were sensitive to verbal or spatial working memory load. The dissociation of short-latency PA and AP sensorimotor circuits and short- and long-latency PA sensorimotor circuits with increasing verbal working memory load support multiple convergent sensorimotor loops that provide distinct functional information to facilitate context-specific supraspinal control.


Subject(s)
Memory, Short-Term , Motor Cortex , Transcranial Magnetic Stimulation , Humans , Memory, Short-Term/physiology , Motor Cortex/physiology , Male , Female , Adult , Young Adult , Spatial Memory/physiology , Reaction Time/physiology , Evoked Potentials, Motor/physiology
8.
PLoS One ; 19(5): e0301118, 2024.
Article in English | MEDLINE | ID: mdl-38753646

ABSTRACT

While the applicability and popularity of theta burst stimulation (TBS) paradigms remain, current knowledge of their neurobiological effects is still limited, especially with respect to their impact on glial cells and neuroinflammatory processes. We used a multimodal imaging approach to assess the effects of a clinical course of TBS on markers for microglia activation and tissue injury as an indirect assessment of neuroinflammatory processes. Healthy non-human primates received continuous TBS (cTBS), intermittent TBS (iTBS), or sham stimulation over the motor cortex at 90% of resting motor threshold. Stimulation was delivered to the awake subjects 5 times a week for 3-4 weeks. Translocator protein (TSPO) expression was evaluated using Positron Emission Tomography and [11C]PBR28, and myo-inositol (mI) and N-acetyl-aspartate (NAA) concentrations were assessed with Magnetic Resonance Spectroscopy. Animals were then euthanized, and immunofluorescence staining was performed using antibodies against TSPO. Paired t-tests showed no significant changes in [11C]PBR28 measurements after stimulation. Similarly, no significant changes in mI and NAA concentrations were found. Post-mortem TSPO evaluation showed comparable mean immunofluorescence intensity after active TBS and sham delivery. The current study suggests that in healthy brains a clinical course of TBS, as evaluated with in-vivo imaging techniques (PET and MRS), did not measurably modulate the expression of glia related markers and metabolite associated with neural viability.


Subject(s)
Biomarkers , Microglia , Positron-Emission Tomography , Animals , Microglia/metabolism , Biomarkers/metabolism , Male , Receptors, GABA/metabolism , Motor Cortex/metabolism , Motor Cortex/diagnostic imaging , Macaca mulatta , Inositol/metabolism
9.
PeerJ ; 12: e17288, 2024.
Article in English | MEDLINE | ID: mdl-38699193

ABSTRACT

Background: The aim of this study is to investigate the acute effects of anodal transcranial direct current stimulation (tDCS) on reaction time, response inhibition and attention in fencers. Methods: Sixteen professional female fencers were recruited, and subjected to anodal tDCS and sham stimulation in the primary motor area (M1) one week apart in a randomized, crossover, single-blind design. A two-factor analysis of variance with repeated measures was used to analyze the effects of stimulation conditions (anodal stimulation, sham stimulation) and time (pre-stimulation, post-stimulation) on reaction time, response inhibition, and attention in fencers. Results: The study found a significant improvement in response inhibition and attention allocation from pre-stimulation to post-stimulation following anodal tDCS but not after sham stimulation. There was no statistically significant improvement in reaction time and selective attention. Conclusions: A single session of anodal tDCS could improve response inhibition, attention allocation in female fencers. This shows that tDCS has potential to improve aspects of an athlete's cognitive performance, although we do not know if such improvements would transfer to improved performance in competition. However, more studies involving all genders, large samples, and different sports groups are needed in the future to further validate the effect of tDCS in improving the cognitive performance of athletes.


Subject(s)
Attention , Cross-Over Studies , Reaction Time , Transcranial Direct Current Stimulation , Humans , Female , Transcranial Direct Current Stimulation/methods , Attention/physiology , Single-Blind Method , Reaction Time/physiology , Young Adult , Adult , Motor Cortex/physiology , Inhibition, Psychological
10.
J Neuroeng Rehabil ; 21(1): 78, 2024 May 14.
Article in English | MEDLINE | ID: mdl-38745322

ABSTRACT

BACKGROUND: Mirror therapy (MT) has been shown to be effective for motor recovery of the upper limb after a stroke. The cerebral mechanisms of mirror therapy involve the precuneus, premotor cortex and primary motor cortex. Activation of the precuneus could be a marker of this effectiveness. MT has some limitations and video therapy (VT) tools are being developed to optimise MT. While the clinical superiority of these new tools remains to be demonstrated, comparing the cerebral mechanisms of these different modalities will provide a better understanding of the related neuroplasticity mechanisms. METHODS: Thirty-three right-handed healthy individuals were included in this study. Participants were equipped with a near-infrared spectroscopy headset covering the precuneus, the premotor cortex and the primary motor cortex of each hemisphere. Each participant performed 3 tasks: a MT task (right hand movement and left visual feedback), a VT task (left visual feedback only) and a control task (right hand movement only). Perception of illusion was rated for MT and VT by asking participants to rate the intensity using a visual analogue scale. The aim of this study was to compare brain activation during MT and VT. We also evaluated the correlation between the precuneus activation and the illusion quality of the visual mirrored feedback. RESULTS: We found a greater activation of the precuneus contralateral to the visual feedback during VT than during MT. We also showed that activation of primary motor cortex and premotor cortex contralateral to visual feedback was more extensive in VT than in MT. Illusion perception was not correlated with precuneus activation. CONCLUSION: VT led to greater activation of a parieto-frontal network than MT. This could result from a greater focus on visual feedback and a reduction in interhemispheric inhibition in VT because of the absence of an associated motor task. These results suggest that VT could promote neuroplasticity mechanisms in people with brain lesions more efficiently than MT. CLINICAL TRIAL REGISTRATION: NCT04738851.


Subject(s)
Feedback, Sensory , Motor Cortex , Spectroscopy, Near-Infrared , Adult , Female , Humans , Male , Young Adult , Brain/physiology , Brain/diagnostic imaging , Feedback, Sensory/physiology , Motor Cortex/physiology , Motor Cortex/diagnostic imaging , Parietal Lobe/physiology , Parietal Lobe/diagnostic imaging , Psychomotor Performance/physiology , Spectroscopy, Near-Infrared/methods
11.
Sci Data ; 11(1): 500, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38750096

ABSTRACT

Here we presented an electrophysiological dataset collected from layer V of the primary motor cortex (M1) and the corresponding behavior dataset from normal and hemi-parkinson rats over 5 consecutive weeks. The electrophysiological dataset was constituted by the raw wideband signal, neuronal spikes, and local field potential (LFP) signal. The open-field test was done and recorded to evaluate the behavior variation of rats among the entire experimental cycle. We conducted technical validation of this dataset through sorting the spike data to form action potential waveforms and analyzing the spectral power of LFP data, then based on these findings a closed-loop DBS protocol was developed by the oscillation activity response of M1 LFP signal. Additionally, this protocol was applied to the hemi-parkinson rat for five consecutive days while simultaneously recording the electrophysiological data. This dataset is currently the only publicly available dataset that includes longitudinal closed-loop DBS recordings, which can be utilized to investigate variations of neuronal activity within the M1 following long-term closed-loop DBS, and explore additional reliable biomarkers.


Subject(s)
Deep Brain Stimulation , Motor Cortex , Animals , Rats , Motor Cortex/physiology , Parkinson Disease/physiopathology , Parkinson Disease/therapy , Action Potentials , Behavior, Animal , Electrophysiological Phenomena , Neurons/physiology
12.
Nat Commun ; 15(1): 4163, 2024 May 16.
Article in English | MEDLINE | ID: mdl-38755145

ABSTRACT

TAR DNA-binding protein 43 (TDP-43) proteinopathy in brain cells is the hallmark of amyotrophic lateral sclerosis (ALS) but its cause remains elusive. Asparaginase-like-1 protein (ASRGL1) cleaves isoaspartates, which alter protein folding and susceptibility to proteolysis. ASRGL1 gene harbors a copy of the human endogenous retrovirus HML-2, whose overexpression contributes to ALS pathogenesis. Here we show that ASRGL1 expression was diminished in ALS brain samples by RNA sequencing, immunohistochemistry, and western blotting. TDP-43 and ASRGL1 colocalized in neurons but, in the absence of ASRGL1, TDP-43 aggregated in the cytoplasm. TDP-43 was found to be prone to isoaspartate formation and a substrate for ASRGL1. ASRGL1 silencing triggered accumulation of misfolded, fragmented, phosphorylated and mislocalized TDP-43 in cultured neurons and motor cortex of female mice. Overexpression of ASRGL1 restored neuronal viability. Overexpression of HML-2 led to ASRGL1 silencing. Loss of ASRGL1 leading to TDP-43 aggregation may be a critical mechanism in ALS pathophysiology.


Subject(s)
Amyotrophic Lateral Sclerosis , DNA-Binding Proteins , Neurons , TDP-43 Proteinopathies , Amyotrophic Lateral Sclerosis/metabolism , Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/pathology , Animals , Humans , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , Mice , Female , TDP-43 Proteinopathies/metabolism , TDP-43 Proteinopathies/pathology , TDP-43 Proteinopathies/genetics , Neurons/metabolism , Neurons/pathology , Brain/metabolism , Brain/pathology , Male , Motor Cortex/metabolism , Motor Cortex/pathology
13.
Sci Rep ; 14(1): 11434, 2024 05 19.
Article in English | MEDLINE | ID: mdl-38763969

ABSTRACT

Sensorimotor control of complex, dynamic systems such as humanoids or quadrupedal robots is notoriously difficult. While artificial systems traditionally employ hierarchical optimisation approaches or black-box policies, recent results in systems neuroscience suggest that complex behaviours such as locomotion and reaching are correlated with limit cycles in the primate motor cortex. A recent result suggests that, when applied to a learned latent space, oscillating patterns of activation can be used to control locomotion in a physical robot. While reminiscent of limit cycles observed in primate motor cortex, these dynamics are unsurprising given the cyclic nature of the robot's behaviour (walking). In this preliminary investigation, we consider how a similar approach extends to a less obviously cyclic behaviour (reaching). This has been explored in prior work using computational simulations. But simulations necessarily make simplifying assumptions that do not necessarily correspond to reality, so do not trivially transfer to real robot platforms. Our primary contribution is to demonstrate that we can infer and control real robot states in a learnt representation using oscillatory dynamics during reaching tasks. We further show that the learned latent representation encodes interpretable movements in the robot's workspace. Compared to robot locomotion, the dynamics that we observe for reaching are not fully cyclic, as they do not begin and end at the same position of latent space. However, they do begin to trace out the shape of a cycle, and, by construction, they are driven by the same underlying oscillatory mechanics.


Subject(s)
Robotics , Walking , Robotics/methods , Walking/physiology , Humans , Animals , Computer Simulation , Locomotion/physiology , Motor Cortex/physiology
14.
Sci Rep ; 14(1): 11744, 2024 05 23.
Article in English | MEDLINE | ID: mdl-38778042

ABSTRACT

Sensorimotor impairments, resulting from conditions like stroke and amputations, can profoundly impact an individual's functional abilities and overall quality of life. Assistive and rehabilitation devices such as prostheses, exo-skeletons, and serious gaming in virtual environments can help to restore some degree of function and alleviate pain after sensorimotor impairments. Myoelectric pattern recognition (MPR) has gained popularity in the past decades as it provides superior control over said devices, and therefore efforts to facilitate and improve performance in MPR can result in better rehabilitation outcomes. One possibility to enhance MPR is to employ transcranial direct current stimulation (tDCS) to facilitate motor learning. Twelve healthy able-bodied individuals participated in this crossover study to determine the effect of tDCS on MPR performance. Baseline training was followed by two sessions of either sham or anodal tDCS using the dominant and non-dominant arms. Assignments were randomized, and the MPR task consisted of 11 different hand/wrist movements, including rest or no movement. Surface electrodes were used to record EMG and the MPR open-source platform, BioPatRec, was used for decoding motor volition in real-time. The motion test was used to evaluate performance. We hypothesized that using anodal tDCS to increase the excitability of the primary motor cortex associated with non-dominant side in able-bodied individuals, will improve motor learning and thus MPR performance. Overall, we found that tDCS enhanced MPR performance, particularly in the non-dominant side. We were able to reject the null hypothesis and improvements in the motion test's completion rate during tDCS (28% change, p-value: 0.023) indicate its potential as an adjunctive tool to enhance MPR and motor learning. tDCS appears promising as a tool to enhance the learning phase of using assistive devices using MPR, such as myoelectric prostheses.


Subject(s)
Electromyography , Transcranial Direct Current Stimulation , Humans , Transcranial Direct Current Stimulation/methods , Male , Female , Adult , Electromyography/methods , Young Adult , Cross-Over Studies , Motor Cortex/physiology , Pattern Recognition, Automated/methods
15.
Nat Commun ; 15(1): 4071, 2024 May 22.
Article in English | MEDLINE | ID: mdl-38778078

ABSTRACT

Adaptive behavior requires integrating prior knowledge of action outcomes and sensory evidence for making decisions while maintaining prior knowledge for future actions. As outcome- and sensory-based decisions are often tested separately, it is unclear how these processes are integrated in the brain. In a tone frequency discrimination task with two sound durations and asymmetric reward blocks, we found that neurons in the medial prefrontal cortex of male mice represented the additive combination of prior reward expectations and choices. The sensory inputs and choices were selectively decoded from the auditory cortex irrespective of reward priors and the secondary motor cortex, respectively, suggesting localized computations of task variables are required within single trials. In contrast, all the recorded regions represented prior values that needed to be maintained across trials. We propose localized and global computations of task variables in different time scales in the cerebral cortex.


Subject(s)
Auditory Cortex , Choice Behavior , Reward , Animals , Male , Choice Behavior/physiology , Mice , Auditory Cortex/physiology , Neurons/physiology , Prefrontal Cortex/physiology , Acoustic Stimulation , Mice, Inbred C57BL , Cerebral Cortex/physiology , Motor Cortex/physiology , Auditory Perception/physiology
16.
PLoS One ; 19(5): e0303983, 2024.
Article in English | MEDLINE | ID: mdl-38781264

ABSTRACT

Despite accumulating evidence that blood flow restriction (BFR) training promotes muscle hypertrophy and strength gain, the underlying neurophysiological mechanisms have rarely been explored. The primary goal of this study is to investigate characteristics of cerebral cortex activity during BFR training under different pressure intensities. 24 males participated in 30% 1RM squat exercise, changes in oxygenated hemoglobin concentration (HbO) in the primary motor cortex (M1), pre-motor cortex (PMC), supplementary motor area (SMA), and dorsolateral prefrontal cortex (DLPFC), were measured by fNIRS. The results showed that HbO increased from 0 mmHg (non-BFR) to 250 mmHg but dropped sharply under 350 mmHg pressure intensity. In addition, HbO and functional connectivity were higher in M1 and PMC-SMA than in DLPFC. Moreover, the significant interaction effect between pressure intensity and ROI for HbO revealed that the regulation of cerebral cortex during BFR training was more pronounced in M1 and PMC-SMA than in DLPFC. In conclusion, low-load resistance training with BFR triggers acute responses in the cerebral cortex, and moderate pressure intensity achieves optimal neural benefits in enhancing cortical activation. M1 and PMC-SMA play crucial roles during BFR training through activation and functional connectivity regulation.


Subject(s)
Cerebral Cortex , Motor Cortex , Resistance Training , Spectroscopy, Near-Infrared , Humans , Male , Resistance Training/methods , Young Adult , Cerebral Cortex/physiology , Cerebral Cortex/blood supply , Cerebral Cortex/metabolism , Cerebral Cortex/diagnostic imaging , Spectroscopy, Near-Infrared/methods , Adult , Motor Cortex/physiology , Motor Cortex/diagnostic imaging , Prefrontal Cortex/physiology , Prefrontal Cortex/blood supply , Prefrontal Cortex/metabolism , Prefrontal Cortex/diagnostic imaging
17.
Sci Rep ; 14(1): 11811, 2024 05 23.
Article in English | MEDLINE | ID: mdl-38782994

ABSTRACT

This study aimed to evaluate the efficacy and safety of navigation-guided repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex in patients with neuropathic pain in the upper limb. This randomized, blinded, sham-controlled, parallel trial included a rTMS protocol (10-Hz, 2000 pulses/session) consisting of five daily sessions, followed by one session per week for the next seven weeks. Pain intensity, as well as pain-related disability, quality of life, and psychological status, were assessed. For the primary outcome, pain intensity was measured daily using a numerical rating scale as a pain diary. Thirty patients were randomly assigned to the active rTMS or sham-stimulation groups. In the primary outcome, the decrease (least square [LS] mean ± standard error) in the weekly average of a pain diary at week 9 compared to the baseline was 0.84 ± 0.31 in the active rTMS group and 0.58 ± 0.29 in the sham group (LS mean difference, 0.26; 95% confidence interval, - 0.60 to 1.13). There was no significant effect on the interaction between the treatment group and time point. Pain-related disability score improved, but other assessments showed no differences. No serious adverse events were observed. This study did not show significant pain relief; however, active rTMS tended to provide better results than sham. rTMS has the potential to improve pain-related disability in addition to pain relief.Clinical Trial Registration number: jRCTs052190110 (20/02/2020).


Subject(s)
Neuralgia , Transcranial Magnetic Stimulation , Upper Extremity , Humans , Male , Female , Transcranial Magnetic Stimulation/methods , Middle Aged , Neuralgia/therapy , Upper Extremity/physiopathology , Aged , Motor Cortex/physiopathology , Adult , Treatment Outcome , Quality of Life , Pain Measurement
18.
Cells ; 13(10)2024 May 07.
Article in English | MEDLINE | ID: mdl-38786016

ABSTRACT

The primary neural circuit affected in Amyotrophic Lateral Sclerosis (ALS) patients is the corticospinal motor circuit, originating in upper motor neurons (UMNs) in the cerebral motor cortex which descend to synapse with the lower motor neurons (LMNs) in the spinal cord to ultimately innervate the skeletal muscle. Perturbation of these neural circuits and consequent loss of both UMNs and LMNs, leading to muscle wastage and impaired movement, is the key pathophysiology observed. Despite decades of research, we are still lacking in ALS disease-modifying treatments. In this review, we document the current research from patient studies, rodent models, and human stem cell models in understanding the mechanisms of corticomotor circuit dysfunction and its implication in ALS. We summarize the current knowledge about cortical UMN dysfunction and degeneration, altered excitability in LMNs, neuromuscular junction degeneration, and the non-cell autonomous role of glial cells in motor circuit dysfunction in relation to ALS. We further highlight the advances in human stem cell technology to model the complex neural circuitry and how these can aid in future studies to better understand the mechanisms of neural circuit dysfunction underpinning ALS.


Subject(s)
Amyotrophic Lateral Sclerosis , Motor Neurons , Amyotrophic Lateral Sclerosis/physiopathology , Amyotrophic Lateral Sclerosis/pathology , Humans , Motor Neurons/pathology , Motor Neurons/physiology , Animals , Nerve Net/physiopathology , Nerve Net/pathology , Neuromuscular Junction/physiopathology , Neuromuscular Junction/pathology , Disease Models, Animal , Motor Cortex/physiopathology , Motor Cortex/pathology
19.
Brain Res Bull ; 212: 110972, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38710310

ABSTRACT

BACKGROUND: Transcranial magnetic stimulation (TMS) combined with electromyography (EMG) has widely been used as a non-invasive brain stimulation tool to assess excitation/inhibition (E/I) balance. E/I imbalance is a putative mechanism underlying symptoms in patients with schizophrenia. Combined TMS-electroencephalography (TMS-EEG) provides a detailed examination of cortical excitability to assess the pathophysiology of schizophrenia. This study aimed to investigate differences in TMS-evoked potentials (TEPs), TMS-related spectral perturbations (TRSP) and intertrial coherence (ITC) between patients with schizophrenia and healthy controls. MATERIALS AND METHODS: TMS was applied over the motor cortex during EEG recording. Differences in TEPs, TRSP and ITC between the patient and healthy subjects were analysed for all electrodes at each time point, by applying multiple independent sample t-tests with a cluster-based permutation analysis to correct for multiple comparisons. RESULTS: Patients demonstrated significantly reduced amplitudes of early and late TEP components compared to healthy controls. Patients also showed a significant reduction of early delta (50-160 ms) and theta TRSP (30-250ms),followed by a reduction in alpha and beta suppression (220-560 ms; 190-420 ms). Patients showed a reduction of both early (50-110 ms) gamma increase and later (180-230 ms) gamma suppression. Finally, the ITC was significantly lower in patients in the alpha band, from 30 to 260 ms. CONCLUSION: Our findings support the putative role of impaired GABA-receptor mediated inhibition in schizophrenia impacting excitatory neurotransmission. Further studies can usefully elucidate mechanisms underlying specific symptoms clusters using TMS-EEG biometrics.


Subject(s)
Cortical Excitability , Electroencephalography , Evoked Potentials, Motor , Motor Cortex , Schizophrenia , Transcranial Magnetic Stimulation , Humans , Transcranial Magnetic Stimulation/methods , Schizophrenia/physiopathology , Male , Female , Adult , Electroencephalography/methods , Motor Cortex/physiopathology , Evoked Potentials, Motor/physiology , Cortical Excitability/physiology , Neural Inhibition/physiology , Middle Aged , Electromyography/methods , Young Adult
20.
Clin Neurol Neurosurg ; 241: 108305, 2024 06.
Article in English | MEDLINE | ID: mdl-38713964

ABSTRACT

OBJECTIVE: Establish the evolution of the connectome before and after resection of motor area glioma using a comparison of connectome maps and high-definition differential tractography (DifT). METHODS: DifT was done using normalized quantitative anisotropy (NQA) with DSI Studio. The quantitative analysis involved obtaining mean NQA and fractional anisotropy (FA) values for the disrupted pathways tracing the corticospinal tract (CST), and white fiber network changes over time. RESULTS: We described the baseline tractography, DifT, and white matter network changes from two patients who underwent resection of an oligodendroglioma (Case 1) and an IDH mutant astrocytoma, grade 4 (Case 2). CASE 1: There was a slight decrease in the diffusion signal of the compromised CST in the immediate postop. The NQA and FA values increased at the 1-year follow-up (0.18 vs. 0.32 and 0.35 vs. 0.44, respectively). CASE 2: There was an important decrease in the immediate postop, followed by an increase in the follow-up. In the 1-year follow-up, the patient presented with radiation necrosis and tumor recurrence, increasing NQA from 0.18 in the preop to 0.29. Fiber network analysis: whole-brain connectome comparison demonstrated no significant changes in the immediate postop. However, in the 1-year follow up there was a notorious reorganization of the fibers in both cases, showing the decreased density of connections. CONCLUSIONS: Connectome studies and DifT constitute new potential tools to predict early reorganization changes in a patient's networks, showing the brain plasticity capacity, and helping to establish timelines for the progression of the tumor and treatment-induced changes.


Subject(s)
Brain Neoplasms , Connectome , Diffusion Tensor Imaging , Feasibility Studies , Glioma , Humans , Diffusion Tensor Imaging/methods , Connectome/methods , Brain Neoplasms/surgery , Brain Neoplasms/diagnostic imaging , Brain Neoplasms/pathology , Glioma/surgery , Glioma/diagnostic imaging , Glioma/pathology , Male , Middle Aged , Adult , Motor Cortex/diagnostic imaging , Motor Cortex/surgery , Motor Cortex/physiopathology , Pyramidal Tracts/diagnostic imaging , Female , Oligodendroglioma/surgery , Oligodendroglioma/diagnostic imaging , Oligodendroglioma/pathology , Astrocytoma/surgery , Astrocytoma/diagnostic imaging , Astrocytoma/pathology
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