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concentration was approaching that of the second impulse, facilitation was increased. In this first experiment, stimuli were presented in intervals of 100 ms between the first and second stimuli. An absolute refractory period was reached when intervals were about 10 ms apart.
This period of time is referred to as the refractory period, which is 250ms in duration and helps to protect the heart. In the classical sense, the cardiac refractory period is separated into an absolute refractory period and a relative refractory period. During the absolute refractory period, a new action potential cannot be elicited.
In the human brain alone, there are over eighty billion neurons. [1] Neurons are diverse with respect to morphology and function. Thus, not all neurons correspond to the stereotypical motor neuron with dendrites and myelinated axons that conduct action potentials.
The period during which no new action potential can be fired is called the absolute refractory period. [43] [44] [45] At longer times, after some but not all of the ion channels have recovered, the axon can be stimulated to produce another action potential, but with a higher threshold, requiring a much stronger depolarization, e.g., to −30 mV.
The refractory period of each channel is therefore vital in propagating the action potential unidirectionally down an axon for proper communication between neurons. When the membrane's voltage becomes low enough, the inactivation gate reopens and the activation gate closes in a process called deinactivation .
The refractory period of each channel is therefore vital in propagating the action potential unidirectionally down an axon for proper communication between neurons. When the membrane's voltage becomes low enough, the inactivation gate reopens and the activation gate closes in a process called deinactivation .
This inability to induce another action potential is known as the absolute refractory period. During the hyperpolarization period, the membrane is again responsive to stimulations but it requires a much higher input to induce an action potential. This phase is known as the relative refractory period.
The afterhyperpolarisation is one of the processes that contribute to the refractory period. Afterhyperpolarization, or AHP, is the hyperpolarizing phase of a neuron's action potential where the cell's membrane potential falls below the normal resting potential. This is also commonly referred to as an action potential's undershoot phase. AHPs ...