Tonic Immobility in the Chicken: Catalepsy Potentiation by Uncontrollable Shock and Alleviation by Imipramine

Attentional control affects the relationship between tonic immobility and intrusive memories

“…That is, physical restraint or entrapment and intense fear are the two conditions that elicit TI. Animals indeed showed increased susceptibility to TI after an uncontrollable than after an escapable shock (Maser & Gallup, 1974). So as a consequence, individuals with poor controllability capacities may be more vulnerable to experience TI.…”

Effects of intraventricular injections of imipramine and 5-hydroxytryptamine on tonic immobility in chickens

“…Intramuscular injections of imipramine practically eradicate tonic immobility (Maser & Gallup, 1974). However, when imipramine was applied intraventricularly, tonic immobility was potentiated rather than attenuated.…”

“…Peripheral injections of imipramine, which blocks serotonin uptake, inhibit raphe activity (Bramwell, 1972;Sheard, Zolovick, & Aghajanian, 1972) and attenuate tonic immobility (Maser & Gallup, 1974). Furthermore, microiontophoretic administration of serotonin suppresses raphe firing (Aghajanian & Haigler, 1973), and intravenous injections of serotonin also suppress immobility (Maser et al, 1975).…”

Fainting in animals

“…All have in common that a potentially dangerous situation evokes immobility [33,42,43]: when sharks are suddenly turned over and held upside down they remain immobile in this position until released. When chickens are fixated, they turn immobile; they then resume activity earlier when the threat appears to go away earlier [22].…”

“…Tonic immobility has been proposed as a model for catalepsy [33,42]. More recently, cataplexy, concerning a flaccid paralysis with intact consciousness evoked by emotions (usually laughter), has been proposed to be an atavistic expression of tonic immobility [6,49].…”