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Additionally, the motor unit action potential is an all-or-none phenomenon - once the recruitment threshold (the stimulus intensity at which a motor unit begins to fire) is reached, it fires fully. Electrical stimulation of nerves reverses the recruitment order, due to the lower resistance of the larger motor neuron axons.
Later, cable theory with its mathematical derivatives allowed ever more sophisticated neuron models to be explored by workers such as Jack, Rall, Redman, Rinzel, Idan Segev, Tuckwell, Bell, and Iannella. More recently, cable theory has been applied to model electrical activity in bundled neurons in the white matter of the brain.
To be specific, motor nerve conduction studies of the Median, Ulnar, and peroneal muscles should be performed, as well as sensory nerve conduction studies of the Ulnar and Sural nerves. [ 9 ] In patients with ALS, it has been shown that distal motor latencies and slowing of conduction velocity worsened as the severity of their muscle weakness ...
A motor neuron (or motoneuron or efferent neuron [1]) is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectly control effector organs, mainly muscles and glands. [2]
As with most neuronal models, increasing the injected current will increase the firing rate of the neuron. One consequence of the Hopf bifurcation is that there is a minimum firing rate. This means that either the neuron is not firing at all (corresponding to zero frequency), or firing at the minimum firing rate.
Mathematically, a neuron's network function () is defined as a composition of other functions (), that can further be decomposed into other functions. This can be conveniently represented as a network structure, with arrows depicting the dependencies between functions.
In biology, 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. [1] Groups of motor units often work together as a motor pool to coordinate the contractions of a single muscle. The concept was proposed ...
Each gap junction (sometimes called a nexus) contains numerous gap junction channels that cross the plasma membranes of both cells. [11] With a lumen diameter of about 1.2 to 2.0 nm, [2] [12] the pore of a gap junction channel is wide enough to allow ions and even medium-size molecules like signaling molecules to flow from one cell to the next, [2] [13] thereby connecting the two cells' cytoplasm.