Escape Avoidance Research Articles

Effects of undernutrition and handling during suckling on shuttle avoidance and footshock escape behavior and on plasma glucose levels of young rats

The present report examined the effects of undernutrition and handling on shuttle and footshock escape avoidance behavior of female rats. Rats were undernourished by feeding their dams a 7% casein diet from birth until 23 days of life. During this period rats were separated from their dams for 4 to 10 min. On days 23 and 24 after delivery, young rats were subjected to sessions in a two-way shuttle avoidance task. The results demonstrated that nonstimulated and stimulated undernourished and stimulated well-nourished rats escape faster than nonstimulated well-nourished animals from footshock during the first session of shuttle avoidance. Further, undernutrition interacted with early stimulation, disrupting the shuttle avoidance behavior of female rats. These results suggest that both undernutrition and early handling can change the footshock behavior of young rats. Undernourished rats presented lower basal glucose levels than well-nourished animals, but responded to shuttle avoidance testing in the same way as do normal rats, increasing the glucose levels.

Self-esteem, social support, internalized homophobia, and coping strategies of HIV+ gay men.

The relationship was examined between self-esteem, social support, internalized homophobia, and coping strategies used by HIV-positive (HIV+) gay men (N = 89) and between the use of coping strategies and mood state. Multiple regressions were conducted with avoidant (escape avoidance, accepting responsibility) and proactive (seeking social support, planful problem solving) coping serving as criterion variables. Greater homophobia and less self-esteem predicted avoidant coping, whereas less homophobia and less time since diagnosis predicted proactive coping. Greater time since diagnosis, less avoidant coping, less homophobia, and greater self-esteem predicted better mood state and accounted for 50% of the total variance.

Scopolamine disrupts visual reversal without affecting the first discrimination

The effect of scopolamine (0.5 mg/kg) was determined in a brightness discrimination test (Y maze) motivated by electrical shocks (escape avoidance). Male adult Sprague Dawley rats were used. Results show that scopolamine impairs significantly the visual reversal without affecting the first brightness discrimination. The qualitative analysis reveals that the anticholinergic drug-induced deficit involves both perserveration, i.e. failure to suppress inappropriate response, and a tendency to adopt a position habit. A parallelism with hippocampal and frontal lobe damage symptoms is discussed and an interpretation in terms of disinhibition and incapacity to solve a more difficult problem is proposed.

Multiple DRO CRF escape avoidance: Contributions of shock duration and response requirements on avoidance

Three rats were trained to escape electric shock by satisfying a continuous (CRF) and a differential reinforcement of other behavior (DRO) escape schedule. These escape schedules, accompanied by visual and auditory cues, were randomly alternated at 5-min intervals in a multiple-schedule format. Each escape schedule was linked with a 20-sec avoidance component (R-S=20 sec), in which responses prevented the occurrence of escape periods. Later, a differential reinforcement of low rate (DRL) escape schedule was paired with the DRO escape schedule. In general, all subjects produced the high (CRF) and low (DRO and DRL) escape rates expected. During the shock-off intervals, two of the three rats maintained higher avoidance in the CRF escape components relative to the DRO escape components, although DRO escape involved longer escape periods. The differential escape rates and avoidance performances indicated reliable stimulus control by the various cues associated with the different escape avoidance schedules employed.

Intermittent Escape Schedules and Their Effects on Avoidance

This experiment was conducted to demonstrate that contingencies present in one negative reinforcement situation may affect the behavior emitted in an alternate negative reinforcement situation. Four rats were exposed to several sessions on a free operant escape avoidance schedule in which the response-shock interval was 20 sec but the escape requirement was varied over sessions. After initial training with a continuous escape schedule which permitted the first response when shock was on to terminate shock, continuous reinforcement escape (CRF escape), two rats had to satisfy various values of a differential reinforcement of low rate escape schedule. The other two rats had to satisfy a yoked interval escape schedule, which permitted the first response after a varying interval of time to terminate shock. In general, although both escape schedules improved avoidance, the differential rein-forcement of low rate escape subjects produced lower escape rates, higher avoidance rates, and avoided more programmed shocks than the yoked interval escape rats. When the subjects were reversed, the differential reinforcement of low rate escape schedule produced an improvement in the number of shocks avoided, and lowered the escape rates of the former yoked interval escape subjects.

Escape/Aggression Incidence in Sexually Abused Juvenile Delinquents

The psychological impact of sexual abuse on children is not a well-understood phenomenon. It has been suggested, however, that such an experience renders the child more aggressive and antisocial. Juvenile delinquency crime data represent a strong test of that assumption. This study reports a continuation of prior research testing a theoretical model which predicts that juveniles subjected to abuse will not become aggressive but will engage in escape and social avoidance behaviors. Analysis of the juvenile delinquency patterns of sexually abused children later arrested for juvenile crimes supported the hypothesis derived from the theoretical model. Abuse did not lead to aggression significantly more than in a control sample of nonabused juveniles, but did significantly increase the frequency of escape infractions.

Behavior during shock exposure as a determinant of subsequent interference with shuttle box escape–avoidance learning in the rat.

Behavior during shock exposure as a determinant of subsequent interference with shuttle box escape–avoidance learning in the rat.

Pharmacological distinctions between "active" and "passive" avoidance memory formation as shown by manipulation of biogenic amine active compounds.

Female CF-1 mice were trained either in a passive step-through avoidance or in an active one-way escape avoidance task. The apparent memory for either task (measured 8 days later) was reduced by reserpine dosage immediately after training. Five-hydroxytryptophane, given along with the reserpine, eliminated memory reduction for the passive training; Dopa, given along with the reserpine, did not eliminate memory deficit for the passive training. Five-hydroxytryptophane given along with reserpine did not eliminate the memory deficit for the active training; Dopa given along with the reserpine did eliminate memory reduction for the active training. Implications are discussed.

Effects of Severe and Inescapable Shock on Subsequent Escape Avoidance and Exploratory Behavior

11 rats which experienced severe, inescapable shock were subsequently found to be impaired in the acquisition of a 2-way shuttle-box avoidance task but showed no impairment in open-field exploration. Ss initially allowed to escape/avoid the shock demonstrated enhanced exploration in the open field.

The effects of conditioned behaviour and environmental factors on plasma corticosteroid levels in pigs

Young pigs have been subjected to various conditioning procedures or environmental factors and the changes in plasma corticosteroid levels measured. Pigs in an escape avoidance situation soon learned to avoid most of the shocks. It was possible to demonstrate conditioned suppression of food reinforced operant behaviour. However, neither the escape avoidance conditioning nor the conditioned suppression technique resulted in large increases in plasma corticosteroids compared with those elicited by administration of ACTH. Exposure of pigs to cold, or chasing them, resulted in larger increases of plasma corticosteroids than the conditioning procedures. A marked 24 hr rhythm in plasma corticosteroid levels was demonstrated.

Emotion as a determinant of the effects of drugs and their combination on different components of behaviour in rats

A sample of 48 rats at two differing levels of emotionality were subjected to tests of rearing, open field ambulation and escape avoidance conditioning, under doses of amphetamine, methylpentynol and their combination. Analysis of scores under the various treatments indicated that the combined treatment facilitated the simpler activities but did not have a comparable effect on conditioning. A complex interaction between treatment and strain (emotionality) and between treatment, strain and dose emerged and is discussed in detail.

An examination of the effects of stimulant and depressant drugs on escape avoidance conditioning in strains of rats selectively bred for emotionality non-emotionality: intertrial activity.

Abstract It is suggested that intertrial activity, which is highly correlated with escape/avoidance conditionability, may be enhanced or reduced by central and autonomic nervous system drugs. Furthermore, it is claimed that these drugs produce their effects in entirely different ways. By employing animals which differed constitutionally in their levels of reactivity, and drugs which were assumed to act differentially upon the mechanisms underlying fear and activation, a systematic examination of these views has been possible. It is shown that a complex interaction exists between the level of emotionality, drugs, and dosage. Some of the parameters of this interaction are outlined and discussed.

The effects of different doses of methylpentynol on escape avoidance conditioning in two strains of rats selectively bred for high and low "emotionality".

Animals from strains selectively inbred for high and low emotionality have been administered varying doses of methylpentynol and then subjected to a discrete escape/avoidance task (buzzer-shock). Results indicate an initial increase in avoidance scores associated with dose level followed by a decrease. There is also a clear “dose” and “strain” effect. No direct difference between the sexes was noted but there is a strong “sex X strain” interaction. The usual superiority of the non-emotional strain on tasks of this type of conditioning is reversed by the drug. The possible biphasic and dual effect of methylpentynol is discussed.