Publications by authors named "Michael Houston"

Several studies have shown interstitial cystitis/bladder pain syndrome (IC/BPS), a chronic condition that poses challenges in both diagnosis and treatment, is associated with painful pelvic floor muscles (PFM) and altered neural drive to these muscles. However, its pathophysiology could also involve other alterations in the electrical activity of PFM motor units (MUs). Studying these alterations could provide novel insights into IC/BPS and help its clinical management.

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Previous studies have shown that beta-band transcranial alternating current stimulation (tACS) applied at the M1 hotspot can modulate corticospinal excitability. However, it remains controversial whether tACS can influence motor unit activities at the spinal cord level. This study aims to compare the efficacy of applying tACS over the hotspot versus the conventional C3 site on motor unit activities and subsequent behavioral changes.

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Article Synopsis
  • After a stroke affecting the corticospinal tract (CST), individuals often experience motor deficits in their upper extremities, such as decreased muscle strength and control.
  • This study compared 15 stroke patients to 28 healthy individuals, focusing on how the ipsilesional CST and contralesional corticoreticulospinal tract (CReST) relate to motor behaviors in the paretic (weakened) arm.
  • Findings indicated that stronger ipsilesional CST projections improved motor control, while stronger contralesional CReST projections improved muscle strength, suggesting their complementary roles in recovery, regardless of whether deficits were in the arm or hand.
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Transcranial electrical stimulation (tES) often targets the EEG-guided C3/C4 area that may not accurately represent M1 for hand muscles. This study aimed to determine if the neuroanatomy-based scalp acupuncture-guided site (AC) was a more effective spot than the C3 site for neuromodulation. Fifteen healthy subjects received one 20-minute session of high-definition transcranial alternating current stimulation (HD-tACS) intervention (20 Hz at 2 mA) at the AC or C3 sites randomly with a 1-week washout period.

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Article Synopsis
  • The study investigates how changes in neural drive and muscle coordination in the upper body affect motor skill learning, focusing on elbow flexor muscles.
  • Participants underwent a six-week training program that involved controlling two synergist elbow flexor muscles while their brain and muscle activity were monitored for connectivity changes.
  • Findings show reductions in inter-muscular and cortico-muscular connectivity, alongside increases in cortico-cortical connectivity, indicating significant neural adaptations related to motor skill development.
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Introduction: Stroke survivors often have motor impairments and related functional deficits. Transcranial Electrical Stimulation (tES) is a rapidly evolving field that offers a wide range of capabilities for modulating brain function, and it is safe and inexpensive. It has the potential for widespread use for post-stroke motor recovery.

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Unlabelled: After corticospinal tract (CST) stroke, several motor deficits in the upper extremity (UE) emerge, including diminished muscle strength, motor control, and muscle individuation. Both the ipsilesional CST and contralesional corticoreticulospinal tract (CReST) innervate the paretic UE and may have different innervation patterns for the proximal and distal UE segments. These patterns may underpin distinct pathway relationships to separable motor behaviors.

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Interstitial cystitis/bladder pain syndrome (IC/BPS) can result in pelvic floor muscle (PFM) overactivity. Current clinical assessment protocols include basic electromyographic assessment of PFM activation; however, they do not provide a comprehensive assessment localized to each region of the PFM. We examined the ability of high-definition features from intravaginal high-density surface electromyography (HD-sEMG) to assess the severity of PFM overactivity in female IC/BPS patients.

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Abnormal intermuscular coordination is a major stroke-induced functional motor impairment in the upper extremity (UE). Previous studies have computationally identified the abnormalities in the intermuscular coordination in the stroke-affected UE and their negative impacts on motor outputs. Therefore, targeting the aberrant muscle synergies has the potential as an effective approach for stroke rehabilitation.

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This study aims to characterize motor unit (MU) features associated with muscle fatigue, using high-density surface electromyography (HD-sEMG). The same MUs recruited before/after, and during muscle fatigue were identified for analysis. The surface location of the innervation zones (IZs) of the MUs was identified from the HD-sEMG bipolar motor unit action potential (MUAP) map.

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The coupled analysis of corticomuscular function based on physiological electrical signals can identify differences in causal relationships between electroencephalogram (EEG) and surface electromyogram (sEMG) in different motor states. The existing methods are mainly devoted to the analysis in the same frequency band, while ignoring the cross-band coupling, which plays an active role in motion control. Considering the inherent multiscale characteristics of physiological signals, a method combining Ordinal Partition Transition Networks (OPTNs) and Multivariate Variational Modal Decomposition (MVMD) was proposed in this paper.

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In musculoskeletal systems, describing accurately the coupling direction and intensity between physiological electrical signals is crucial. The maximum information coefficient (MIC) can effectively quantify the coupling strength, especially for short time series. However, it cannot identify the direction of information transmission.

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Objective- This study aims to develop a novel framework for high-density surface electromyography (HD-sEMG) signal decomposition with superior decomposition yield and accuracy, especially for low-energy MUs. Methods- An iterative convolution kernel compensation-peel off (ICKC-P) framework is proposed, which consists of three steps: decomposition of the motor units (MUs) with relatively large energy by using the iterative convolution kernel compensation (ICKC) method and extraction of low-energy MUs with a Post-Processor and novel 'peel-off' strategy. Results- The performance of the proposed framework was evaluated by both simulated and experimental HD-sEMG signals.

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Purpose: Interstitial cystitis/bladder pain syndrome patients can experience overactive pelvic floor muscle activity at rest. While the frequency power spectrum of pelvic floor muscle has briefly been explored, intermuscular connectivity of the pelvic floor muscle has yet to be studied, which may provide useful insight into the neurological component, ie, neural drive to muscles, in interstitial cystitis/bladder pain syndrome.

Materials And Methods: High-density surface electromyography was collected from 15 female interstitial cystitis/bladder pain syndrome patients with pelvic floor tenderness and 15 urologically healthy female controls.

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Motor imagery (MI) electroencephalogram (EEG) signals have an important role in brain-computer interface (BCI) research. However, effectively decoding these signals remains a problem to be solved. Traditional EEG signal decoding algorithms rely on parameter design to extract features, whereas deep learning algorithms represented by convolution neural network (CNN) can automatically extract features, which is more suitable for BCI applications.

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Accurate anatomical matching for patient-specific electromyographic (EMG) mapping is crucial yet technically challenging in various medical disciplines. The fixed electrode construction of multielectrode arrays (MEAs) makes it nearly impossible to match an individual's unique muscle anatomy. This mismatch between the MEAs and target muscles leads to missing relevant muscle activity, highly redundant data, complicated electrode placement optimization, and inaccuracies in classification algorithms.

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Study Objective: To determine the efficacy of using platelet-rich plasma (PRP) for vaginal wall repair in rats with vaginal wall impairment induced by vaginal distension (VD).

Design: A single-blind, randomized study.

Setting: A certified animal research facility.

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Brain-computer interface (BCI) is a technology that connects the human brain and external devices. Many studies have shown the possibility of using it to restore motor control in stroke patients. One specific challenge of such BCI is that the classification accuracy is not high enough for multi-class movements.

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Background: Cotton with resistance to 2,4-d choline, glufosinate and glyphosate allows over-the-top use of these herbicides for postemergence weed control. Nontransgenic cotton is highly responsive to low rates of 2,4-d, causing concern among farmers when the herbicide is applied near the crop. Injury to nearby cotton following application of 2,4-d choline is sometimes blamed on volatilization of the herbicide.

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Muscle coordination and motor function of stroke patients are weakened by stroke-related motor impairments. Our earlier studies have determined alterations in inter-muscular coordination patterns (muscle synergies). However, the functional connectivity of these synergistically paired or unpaired muscles is still unclear in stroke patients.

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Hand gesture recognition using high-density surface electromyography (HD-sEMG) has gained increasing attention recently due its advantages of high spatio-temporal resolution. Convolutional neural networks (CNN) have also recently been implemented to learn the spatio-temporal features from the instantaneous samples of HD-sEMG signals. While the CNN itself learns the features from the input signal it has not been considered whether certain pre-processing techniques can further improve the classification accuracies established by previous studies.

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Muscle networks describe the functional connectivity between muscles quantified through the decomposition of intermuscular coherence (IMC) to identify shared frequencies at which certain muscles are co-modulated by common neural input. Efforts have been devoted to characterizing muscle networks in healthy subjects but stroke-linked alterations to muscle networks remain unexplored. Muscle networks were assessed for eight key upper extremity muscles during isometric force generation in stroke survivors with mild, moderate, and severe impairment and compared against healthy controls to identify stroke-specificalterations in muscle connectivity.

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Synthetic messenger RNA (mRNA)-based therapeutics are an increasingly popular approach to gene and cell therapies, genome engineering, enzyme replacement therapy, and now, during the global SARS-CoV-2 pandemic, vaccine development. mRNA for such purposes can be synthesized through an enzymatic in vitro transcription (IVT) reaction and formulated for in vivo delivery. Mature mRNA requires a 5'-cap for gene expression and mRNA stability.

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