Intermuscular Coherence is a measure to quantify correlations between the activity of two
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 muscl ...
s, which is often assessed using
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 electromyog ...
. The correlations in muscle activity are quantified in
frequency domain, and therefore referred to as intermuscular
coherence
Coherence, coherency, or coherent may refer to the following:
Physics
* Coherence (physics), an ideal property of waves that enables stationary (i.e. temporally and spatially constant) interference
* Coherence (units of measurement), a deriv ...
.
[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 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 mot ...
s 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.
Physiology
Intermuscular coherence can be used to investigate the neural circuitry involved in motor control. Correlated muscle activity indicates common input to the motor unit pools of both muscles and reflects shared neural pathways (including cortical, subcortical and spinal) that contribute to muscle activity and movement. The strength of intermuscular coherence is dependent on the relationship between muscles and is generally stronger between muscle pairs that are anatomically and functionally closely related. Intermuscular coherence can therefore be used to identify impairments in motor pathways.
See also
*
Corticomuscular coherence
*
Corticocortical coherence
References
External links
Neurspec Toolbox for MATLAB
Neuroscience
Neurophysiology
{{med-diagnostic-stub