all-or-none response

all-or-none phenomenon

The property of cardiac muscle in which stimulation from a single myocyte travels to the atrium and ventricle before contracting, resulting in a coherent and co-ordinated pump activity.
A rule applied to the activation of individual muscle or nerve cells, where the response to stimuli (depolarisation) only occurs above a certain threshold, usually –55 mV, after which a complete action potential occurs that is maximum in intensity—i.e., the strength of the nerve impulse is not dependent on, or a function of, the strength of the stimulus.
A “soft” rule in behavioural studies, which refers to the observation that a behavioural stimulus will produce either a complete response or none at all.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
References in periodicals archive ?
Copies of these records are available upon request.) This alternating all-or-none response pattern was observed under both the FR 300 schedule and then under the FR 600 schedule.
The results showed that, first, the FR 300 response requirement produced a consistent all-or-none response pattern across dyad members, and second, with a history of responding under this response requirement, the all-or-none response pattern develops at the higher ratio.
During baseline, responding by two of the three dyads (W:K, W:M) was characterized by an approximately even division between the LL and RR order-of-responding category (the alternating all-or-none response pattern observed previously).
(The other subject's percentage of responding was 100% minus the percentage shown.) During the last five baseline sessions (20-20 point value), subjects divided their responding approximately evenly for each session, replicating the alternating all-or-none response pattern observed earlier.
Two other studies were excluded from statistical analysis because of identical all-or-none responses in the patch and no-patch groups: 1 study had a 0% healing rate in both groups on day 1; the other had a 100% resolution of the abrasion in both the experimental and control groups at day 2.