startle reaction

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startle reaction

 [stahr´t'l]
the various psychophysiological phenomena, including involuntary motor and autonomic reactions, evidenced by an individual in reaction to a sudden, unexpected stimulus, as a loud noise.

star·tle re·flex

a primitive reflex response observed in the normal newborn but typically suppressed by 3-4 months of age. Any sudden stimulus (for example, a loud noise, a blow to the supporting surface, or being dropped 5-10 cm through space) causes flexion of the hip and knee joints with fanning of the fingers followed by fist clenching and extension of the upper limbs followed by flexion. Synonym(s): Moro reflex, parachute reflex, startle reaction
See also: cochleopalpebral reflex.

startle reaction

the mental state of suddenly aroused awareness; manifested by a flight or fight or submit pattern of behavior and posture.
References in periodicals archive ?
2002) found larger startle responses for unpleasant than for pleasant pictures, suggesting an emotional modulation in addition to that explained by stimulus arousal.
Timing of the acoustical startle response in mice: Habituation and dishabituation as a function of the interstimulus interval.
In the minor form, the startle response is exaggerated without any additional symptoms such as generalised stiffness.
Persistent symptoms of increased arousal (not present before the trauma), as indicated by 2 (or more) of the following: * Difficulty falling or staying asleep * Irritability or outbursts of anger * Difficulty concentrating * Hypervigilance * Exaggerated startle response E.
These symptoms include recurring thoughts of a past trauma, intense distress when reminded of the event, feelings of detachment, and an exaggerated startle response.
Apnea is characterized by frequent pauses in respiration sometimes followed by a startle response or limb twitch as breathing resumes.
This study found that [beta]2 knock-out mice exhibited reduced sensitivity to alcohol-induced depression of the acoustic startle response described above, suggesting that [beta]2-containing receptors modulate this effect of alcohol.
Cerebellar vermis: essential for long-term habituation of the acoustic startle response.
Under severe levels of stress, your body may react with a startle response, and Body Alarm Reaction (BAR) will take over.
Compared to placebo, the acoustic startle response was diminished 60 and 90 min after the administration of one dose of gotu kola.
The two lower doses in this study prompted greater change than the highest dose for auditory startle response, mating behavior, and body weight.