Richard F. Nash

Psychophysiological correlates of tonic immobility in the domestic chicken (Gallus gallus)

Abstract Three experiments were conducted measuring within-animal changes in heart rate, respiration rate, and body temperature during tonic immobility. Following immobility onset, heart rate decreased and reached its lowest level just prior to response termination, respiration rate increased initially and then gradually decreased during the immobility episode, while body temperature remained lowered throughout the response period. The results were discussed in relation to the hypothesis that immobility might be related to an aversive emotional state.

Habituation and Tonic Immobility in Chickens: Strain Comparisons

Research has demonstrated substantial strain differences among chickens in the duration of tonic immobility. The present study was designed to compare the habituation of immobility in White Leghorn and Production Red chickens. Experiment 1 replicated other research by showing that (a) repeated elicitation of immobility, and not just handling, was responsible for reduced response durations for both strains; and (b) White Leghorns displayed significantly longer response durations compared to Production Reds. Retention of habituation of immobility in White Leghorns was explored in a second experiment and was found to replicate the lack of spontaneous recovery noted in other research with Production Reds.

Heart Rate and Competitive Decision Making

The viability of combining experimental-game and physiological measurement techniques to establish relationships between heart rate and competitive decision making was demonstrated. The results indicated that heart rate was a reliable predictor of success in a competitive decision-making situation, a zero-sum game, for males but not for females.

Effect of different parameters of shock on tonic immobility

Four separate experiments were conducted with chickens to explore the effects of various parameters of electric shock on tonic immobility. Immobilizing subjects at varying times after the receipt of shock affected the duration of immobility only after delays of over 15 min. Duration of shock affected immobility differently, depending upon whether alternating current or continuous direct current was used. The effects of continuous dc, pulsating dc. and ac shock were also examined. The results were discussed in terms of shock onset-offset characteristics being an important consideration.

Effect of the Visual Presence of an Experimenter on the Maintenance of Tonic Immobility in Domestic Chickens (Gallus Gallus)

The importance of the visual presence of an experimenter both during the induction of tonic immobility and during the immobility response itself was investigated. The results suggested that it is the visual presence of an experimenter during the immobility response itself, and not during its initiation, that is critical for delaying recovery from immobility. Methodological and theoretical implications were discussed.

Long-Term Retention of the Habituation of Tonic Immobility

Previous research has suggested that the tonic immobility response in chickens displays long-term retention of habituation. However, a possible alternative interpretation based on overhabituation had not been ruled out. The results of this research showed no evidence for spontaneous recovery of immobility for up to 30 days after habituation training, with overhabituation effects taken into consideration. Such long-term effects may pose problems for current theories of habituation.

Effect of neurotransmitter reuptake blockers on tonic immobility in chickens

This research was undertaken to investigate the effects of two neurotransmitter reuptake blockers, nisoxetine and fluoxetine, on the tonic immobility (TI) response. In Experiment 1, nisoxetine was found to significantly diminish both the duration of the TI response and the number of inductions needed to elicit it. These results were discussed in terms of the drug’s effects on dopaminergic and/or serotonergic systems with the implication of possible competing locomotor response effects. Fluoxetine, in Experiment 2, was found to have no significant effect on either the duration of TI or the number of inductions needed to elicit it. Additional research with fluoxetine was suggested as necessary, with the possible use of an intraventricular route for administration of the drug.