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The stimulus is automatically decreased in steps of a set percentage until the response falls below the target (generation of an action potential). Thereafter, the stimulus is stepped up or down depending on whether the previous response was lesser or greater than the target response until a resting (or control) threshold has been established.
v. t. e. In physiology, a stimulus[ 1 ] is a change in a living thing's internal or external environment. This change can be detected by an organism or organ using sensitivity, and leads to a physiological reaction. [ 2 ] Sensory receptors can receive stimuli from outside the body, as in touch receptors found in the skin or light receptors in ...
As an action potential (nerve impulse) travels down an axonthere is a change in electric polarity across the membraneof the axon. In response to a signal from another neuron, sodium- (Na+) and potassium- (K+)–gated ion channelsopen and close as the membrane reaches its threshold potential. Na+channels open at the beginning of the action ...
Rate dependence of the action potential is a fundamental property of cardiac cells and alterations can lead to severe cardiac diseases including cardiac arrhythmia and sometimes sudden death. [3] Action potential activity within the heart can be recorded to produce an electrocardiogram (ECG). This is a series of upward and downward spikes ...
A receptor potential, also known as a generator potential, [1] a type of graded potential, is the transmembrane potential difference produced by activation of a sensory receptor. [2] A receptor potential is often produced by sensory transduction. [3] It is generally a depolarizing event resulting from inward current flow.
Graded potentials are changes in membrane potential that vary according to the size of the stimulus, as opposed to being all-or-none. They include diverse potentials such as receptor potentials, electrotonic potentials, subthreshold membrane potential oscillations, slow-wave potential, pacemaker potentials, and synaptic potentials.
An event-related potential (ERP) is the measured brain response that is the direct result of a specific sensory, cognitive, or motor event. [ 1 ] More formally, it is any stereotyped electrophysiological response to a stimulus. The study of the brain in this way provides a noninvasive means of evaluating brain functioning.
All-or-none law. In physiology, the all-or-none law (sometimes the all-or-none principle or all-or-nothing law) is the principle that if a single nerve fibre is stimulated, it will always give a maximal response and produce an electrical impulse of a single amplitude. If the intensity or duration of the stimulus is increased, the height of the ...