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Intermuscular Coherence
Intermuscular Coherence is a measure to quantify correlations between the activity of two muscles, which is often assessed using electromyography. The correlations in muscle activity are quantified in frequency domain, and therefore referred to as intermuscular coherence.Farmer, S. F., Bremner, F. D., Halliday, D. M., Rosenberg, J. R., & Stephens, J. A. (1993). The frequency content of common synaptic inputs to motoneurones studied during voluntary isometric contraction in man. The Journal of Physiology, 470(1), 127–155 History The synchronisation of motor units of a single muscle in animals and humans are known for decades. The early studies that investigated the relationship of EMG activity used time-domain cross-correlation to quantify common input. The explicit notion of presence of synchrony between motor units of two different muscles was reported at a later time. In the 1990s, coherence analysis was introduced to examine in frequency content of common input. Physiolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle tissue, and are often known as muscle fibers. The muscle tissue of a skeletal muscle is striated – having a striped appearance due to the arrangement of the sarcomeres. Skeletal muscles are voluntary muscles under the control of the somatic nervous system. The other types of muscle are cardiac muscle which is also striated and smooth muscle which is non-striated; both of these types of muscle tissue are classified as involuntary, or, under the control of the autonomic nervous system. A skeletal muscle contains multiple fascicles – bundles of muscle fibers. Each individual fiber, and each muscle is surrounded by a type of connective tissue layer of fascia. Muscle fibers are formed from the fusion of developmental myoblasts in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromyography
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyograph detects the electric potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect abnormalities, activation level, or recruitment order, or to analyze the biomechanics of human or animal movement. Needle EMG is an electrodiagnostic medicine technique commonly used by neurologists. Surface EMG is a non-medical procedure used to assess muscle activation by several professionals, including physiotherapists, kinesiologists and biomedical engineers. In Computer Science, EMG is also used as middleware in gesture recognition towards allowing the input of physical action to a computer as a form of human-computer interaction. Clinical uses EMG testing has a variety of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Domain
In physics, electronics, control systems engineering, and statistics, the frequency domain refers to the analysis of mathematical functions or signals with respect to frequency, rather than time. Put simply, a time-domain graph shows how a signal changes over time, whereas a frequency-domain graph shows how much of the signal lies within each given frequency band over a range of frequencies. A frequency-domain representation can also include information on the phase shift that must be applied to each sinusoid in order to be able to recombine the frequency components to recover the original time signal. A given function or signal can be converted between the time and frequency domains with a pair of mathematical operators called transforms. An example is the Fourier transform, which converts a time function into a complex valued sum or integral of sine waves of different frequencies, with amplitudes and phases, each of which represents a frequency component. The "spectrum" of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coherence (signal Processing)
In signal processing, the coherence is a statistic that can be used to examine the relation between two signals or data sets. It is commonly used to estimate the power transfer between input and output of a linear system. If the signals are ergodic, and the system function is linear, it can be used to estimate the causality between the input and output. Definition and formulation The coherence (sometimes called magnitude-squared coherence) between two signals x(t) and y(t) is a real-valued function that is defined as: ::C_(f) = \frac where Gxy(f) is the Cross-spectral density between x and y, and Gxx(f) and Gyy(f) the auto spectral density of x and y respectively. The magnitude of the spectral density is denoted as , G, . Given the restrictions noted above (ergodicity, linearity) the coherence function estimates the extent to which y(t) may be predicted from x(t) by an optimum linear least squares function. Values of coherence will always satisfy 0\le C_(f)\le 1. For an ''ideal' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neural Oscillation
Neural oscillations, or brainwaves, are rhythmic or repetitive patterns of neural activity in the central nervous system. Neural tissue can generate oscillatory activity in many ways, driven either by mechanisms within individual neurons or by interactions between neurons. In individual neurons, oscillations can appear either as oscillations in membrane potential or as rhythmic patterns of action potentials, which then produce oscillatory activation of post-synaptic neurons. At the level of neural ensembles, synchronized activity of large numbers of neurons can give rise to macroscopic oscillations, which can be observed in an electroencephalogram. Oscillatory activity in groups of neurons generally arises from feedback connections between the neurons that result in the synchronization of their firing patterns. The interaction between neurons can give rise to oscillations at a different frequency than the firing frequency of individual neurons. A well-known example of macrosco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motor Unit
A motor unit is made up of a motor neuron and all of the skeletal muscle fibers innervated by the neuron's axon terminals, including the neuromuscular junctions between the neuron and the fibres. Groups of motor units often work together as a motor pool to coordinate the contractions of a single muscle. The concept was proposed by Charles Scott Sherrington. All muscle fibers in a motor unit are of the same fiber type. When a motor unit is activated, all of its fibers contract. In vertebrates, the force of a muscle contraction is controlled by the number of activated motor units. The number of muscle fibers within each unit can vary within a particular muscle and even more from muscle to muscle; the muscles that act on the largest body masses have motor units that contain more muscle fibers, whereas smaller muscles contain fewer muscle fibers in each motor unit. For instance, thigh muscles can have a thousand fibers in each unit, while extraocular muscles might have ten. Muscles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corticomuscular Coherence
Corticomuscular Coherence relates to the synchrony in the neural activity of brain's cortical areas and muscle. The neural activities are picked up by electrophysiological recordings from the brain (e.g. EEG, MEG, ECoG, etc.) and muscle ( EMG). It is a method to study the neural control of movement. Physiology Corticomuscular Coherence was initially reported between MEG and EMG and is widely studied between EMG and EEG, MEG, etc. The origins of corticomuscular coherence seem to be communication in corticospinal pathways between primary motor cortex and muscles. While the role of descending corticomuscular pathways in generation of coherence are more clear, the role of ascending sensory spinocortical pathways are less certain. Corticomuscular coherence has been of special interest in alpha band (about 10 Hz), in Beta band (15–30 Hz), and in Gamma band (35–60 Hz). Mathematics and Statistics A classic and commonly used approach to assess the synchrony bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corticocortical Coherence
Corticocortical coherence is referred to the synchrony in the neural activity of different cortical brain areas. The neural activities are picked up by electrophysiological recordings from the brain (e.g. EEG, MEG, ECoG, etc.). It is a method to study the brain's neural communication and function at rest or during functional tasks. History and basics Initial applications of spectral analysis for finding the relationship between the EEG recordings from different regions of scalp dates back to 1960's. Corticocortical coherence has since been extensively studied using EEG and MEG recording for potential diagnostic applications and beyond. The exact origins of corticocortical coherence are under active investigation. While the consensus suggests that the functional neural communication between distinct brain sources leads to synchronous activity in those regions (possibly connected by neural tracts, in either direct or indirect way), an alternative explanation emphasises on single ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroscience
Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, developmental biology, cytology, psychology, physics, computer science, chemistry, medicine, statistics, and Mathematical Modeling, mathematical modeling to understand the fundamental and emergent properties of neurons, glia and neural circuits. The understanding of the biological basis of learning, memory, behavior, perception, and consciousness has been described by Eric Kandel as the "epic challenge" of the Biology, biological sciences. The scope of neuroscience has broadened over time to include different approaches used to study the nervous system at different scales. The techniques used by neuroscientists have expanded enormously, from molecular biology, molecular and cell biology, cellular studies of individual neurons to neuroimaging, imaging ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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