Percent time or duration spent immobile except for respiration during fear, threat, or defensive-behavior assays.
Use freezing when the experiment asks whether a conditioned cue, context, or acute threat suppresses movement. Do not treat freezing as a complete measure of fear by itself: defensive state can also appear as flight, darting, risk assessment, avoidance, or general hypoactivity. Freezing is strongest when the immobility threshold, scoring epoch, context, and baseline activity checks are fixed before analysis.
| Primary value | Immobility except breathing during a defined scoring epoch |
|---|---|
| Common units | Percent session time, total seconds, bout count, mean bout duration |
| Compatible assays | Contextual fear conditioning, cued fear conditioning, extinction, avoidance, looming threat, open-field threat tests |
| Required boundary | Movement threshold and minimum immobility duration |
| Do not infer alone | Specific emotion, memory strength, analgesia, sedation, or motor ability |
Score freezing from a predefined movement threshold, a minimum duration rule, and a fixed analysis window. Baseline movement before the conditioned stimulus or context exposure should be stored so high freezing is not confused with pre-existing inactivity.
Increased freezing often supports stronger conditioned defensive responding, but it can be distorted by sedation, motor impairment, pain, illness, thermal stress, chamber novelty, or an animal shifting from freezing to flight.
Store animal ID, session phase, cue or context, frame rate, motion threshold, minimum freeze duration, percent freezing, total seconds, bout count, excluded intervals, and scorer or software version.
Endpoint pages should cite the method literature behind the scored value and keep high-specificity protocol claims qualified unless the source supports them.
Endpoint articles link to adjacent products, software workflows, and sibling endpoints where the connection is useful and already routable.
