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Neurons generate action potentials resulting from changes in the electric membrane potential. Neurons can generate multiple action potentials in sequence forming so-called spike trains. These spike trains are the basis for neural coding and information transfer in the brain.
Motor neurons with large cell bodies tend to innervate fast-twitch, high-force, less fatigue-resistant muscle fibers, whereas motor neurons with small cell bodies tend to innervate slow-twitch, low-force, fatigue-resistant muscle fibers. In order to contract a particular muscle, motor neurons with small cell bodies are recruited (i.e. begin to ...
The neurons in area 5 play a role in the initiation and execution of movement and respond at enormously quick speeds. An EMG (electromyogram) is a test of electrical activity in muscles. The neurons in area 5 respond at least 100ms faster than EMG detectable activity allows.
These up-and-down cycles are known as action potentials. In some types of neurons, the entire up-and-down cycle takes place in a few thousandths of a second. In muscle cells, a typical action potential lasts about a fifth of a second. In plant cells, an action potential may last three seconds or more. [4]
Neuronal activity at the microscopic level has a stochastic character, with atomic collisions and agitation, that may be termed "noise." [4] While it isn't clear on what theoretical basis neuronal responses involved in perceptual processes can be segregated into a "neuronal noise" versus a "signal" component, and how such a proposed dichotomy could be corroborated empirically, a number of ...
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.
Say you have a 4-year-old Labrador named Comet — with the new equation, Comet's real "dog age" would be slightly older than 53. The reason for the difference is actually pretty simple.
Myelinated axons only allow action potentials to occur at the unmyelinated nodes of Ranvier that occur between the myelinated internodes. It is by this restriction that saltatory conduction propagates an action potential along the axon of a neuron at rates significantly higher than would be possible in unmyelinated axons (150 m/s compared from 0.5 to 10 m/s). [1]