Effects of non-contact exposure to rodents on defensive behaviors in mice.

These experiments explored the effects of non-contact exposure to two rodent species (rats and gerbils) on the defensive behaviors of male CD-1 mice. In Experiment 1 it was found that rats evoked substantial levels of defensiveness which were positively related to increases in rat activity. This effect was considerably attenuated, but still detectable, 30 min after rat exposure (Experiment 2).

Immediate and long-term effects of novel odors on risk assessment in mice.

The effects novel predator and nonpredator odors on risk assessment and nonagonistic behaviors were investigated in a series of 4 experiments. During initial exposure, a synthetic predator odor proved to be no more effective than sheeps' wool in evoking defensive behaviors among either naive or previously defeated mice. When the mice were tested following 60-min habituation to the odors, the predator odor consistently elicited stronger defensiveness than sheeps' wool.

Differential effects of prior dominance or subordination experience on conspecific odor preferences in mice.

Preferences for the soiled bedding odors of familiar and unfamiliar conspecifics were assessed among male mice rendered dominant or subordinate by a series of resident-intruder encounters. Alpha males preferred the odors of their familiar antagonist most strongly. Subordinates, in contrast, showed strongest preferences for unfamiliar females and a weaker preference for alpha odors.

Test-specific effects of FG-7142 on isolation-induced aggression in mice.

Treatment with FG-7142 decreased isolation-induced attack, but not defense, by male mice when the residents' home cages contained only a sawdust substrate. When a small wooden nesting box was added to the cage (Experiment 2), however, FG-7142 somewhat increased levels of attack. Time spent in the nesting box was also increased, while overall levels of social interaction were decreased, by drug treatment in Experiment 2.

Effects of eltoprazine hydrochloride on reactivity to conspecific or novel odors and activity.

Treatment with eltoprazine (DU 28853) increased the number of entries by male mice into compartments containing the odors of male and female conspecifics. This effect was most pronounced when odors were provided by previously defeated males. In contrast, the drug had no effect upon responsiveness to the odors of cinnamon and chocolate.

Effects of yohimbine on isolation-induced aggression, social attraction, and conspecific odor preference in mice.

Yohimbine treatment inhibited isolation-induced attack in mice but had no effect on defense. The drug also increased social distances and produced a transient decrease in preference for conspecific male odors. The antiaggressive actions of yohimbine parallel those reported for the anxiogenic beta-carbolines and for phenylpiperazine "serenic" agents.

Effects of eltoprazine hydrochloride on exploratory behavior and social attraction in mice.

The effects of eltoprazine (DU 28853) on exploratory behavior and conspecific social attraction were examined in four experiments. Drug treatments somewhat enhanced three forms of exploratory behavior but decreased social attraction. The results indicate that eltoprazine, in sharp contrast to fluprazine, weakly ameliorates neophobic responses.

Effects of regional amygdaloid lesions on flight and defensive behaviors of wild black rats (Rattus rattus).

Flight and defensive behaviors of wild black rats (R. rattus) in response to nonpainful threatening stimuli were examined before and after regional amygdaloid lesions. Striking disruption of flight was found following damage to all major amygdaloid regions.

Effects of fluprazine hydrochloride on maternal behaviour in mice.

Fluprazine hydrochloride treatment disrupted both retrieval and nursing components of maternal behaviour when dam and pups were separated for a 30 min post-infection interval. Subsequent experiments revealed that pup contact during this interval, even when restricted to visual/auditory stimulation, abolished the drug's effect on nursing but not retrieval. Fluprazine appears to strongly and consistently disrupt retrieval while its effects on nursing appear more indirectly mediated.

Effects of food deprivation on caffeine consumption in male and female rats.

The effect of food deprivation on caffeine consumption was investigated in male and female rats utilizing two-bottle preference tests. During ad lib food and water access, proportional consumption of six increasingly concentrated caffeine solutions (0.01-0.

Effects of septal-forebrain lesions on maternal aggression and maternal care.

Septal-forebrain lesions significantly increased the defensive reactions of lactating Long-Evans rats (n = 13) relative to nonlesioned control females. The lesions greatly enhanced defensive behaviors on a number of standard tests (e.g.

Effects of fluprazine hydrochloride on conspecific odor preferences in rats.

The effect of Fluprazine Hydrochloride (DU 27716) on preference for conspecific male, estrous female and food odors was examined in male rats utilizing a two-compartment choice apparatus. Treatment with 8.0 mg/kg Fluprazine enhanced the preference of males for male odors but had no effect on preference for either estrous female or food odors.

Fluprazine hydrochloride does not decrease defensive behaviors of wild and septal syndrome rats.

Recent studies indicate that fluprazine hydrochloride reduces offensive attack in laboratory rats and mice without decreasing defensive behavior during conspecific encounters. Since wild rats and rats displaying the "septal lesion syndrome" show much more pronounced defensive reactions than do normal laboratory rats, these animals were used to provide a more critical test of fluprazine's effectiveness on defense. When a dose of fluprazine hydrochloride (8 mg/kg), previously shown to be highly effective in reducing or eliminating offense, was given to wild and septal syndrome rats these animals showed no reliable decrement in a wide range of defensive reactions including biting attack (defensive attack) to human handling and other stimulation.

Mouse killing, insect predation, and conspecific attack by rats with differing prior aggressive experience.

Mouse-killing, cockroach predation, and conspecific attack were examined in male Long-Evans rats with a history of intraspecific aggression (n = 20), defeat (n = 20), or no aggressive experience (n = 20). Roaches were more likely to be attacked during 30 min tests, and were attacked more rapidly than mice or rats regardless of previous social experience of subjects. Rats with aggressive experience attacked conspecifics more readily than subjects with defeat or no experience.

Sex differences in shock motivated behaviors, activity, and discrimination learning of northern grasshopper mice (Onychomys leucogaster).

Sex differences in the behavior of the highly predatory northern grasshopper mouse (Onychomys leucogaster) were investigated in a series of eight experiments. Female mice acquired two-way avoidance behavior more slowly, but passive avoidance more rapidly, than males. Females also buried a shock probe more completely than males and showed more escape behavior during open field testing.

Taming in wild rats following medial amygdaloid lesions.

Flight behavior, startle reactions, and defensiveness to nonpainful stimuli were examined before and after medial amygdaloid lesions in wild Rattus norvegicus and R. rattus. Lesions which included bilateral damage to the medial nucleus strongly reduced defensiveness but had no effect on flight behavior.

Social play behaviours and insect predation in northern grasshopper mice (Onychomys leucogaster).

Play behaviours of northern grasshopper mice, Onychomys leucogaster , were observed from 27 to 61 days of age and after a brief period of social isolation. The mice were also observed during a simple test of cricket predation. With the exception of an active play-soliciting response, the play behaviours were quite similar to those described for other rodents.

Effects of varied prior manipulatory or consummatory behaviours on nut opening, predation, novel foods consumption, nest building, and food tablet grasping in rats.

Varied manipulatory-gnawing experience with nonfood objects facilitated later nut opening and insect predation in rats. Varied food consumption, which minimized manipulation, facilitated the hulling and consumption of sunflower seeds. Both treatments weakly facilitated forepaw food tablet grasping but neither treatment altered novel foods consumption or nest building.

Effects of basolateral or corticomedial amygdaloid lesions on grooming, consummatory, and locomotor behaviours in rats.

Grooming behaviour in rats was induced by limited water access and by water spray before and after corticomedial or basolateral amygdaloid lesions or control operations. Corticomedial lesions produced some attenuation of grooming induced by limited water access but increased grooming induced by water spray. Basolateral lesions did not consistently affect grooming.

Persistent depression of rearing behavior in rats after extensive septal lesions.

Extensive septal lesions produced a persistent (76 days) reduction in rearing behavior which was not directly attributable to altered deprivation states, emotionality, activity levels, or competing behaviors and which occurred in familiar as well as various novel testing environments. Changes in visual, olfactory, or conspecific stimuli ameliorated or had no effect on the lesion effect. The results indicate that the septal area is importantly involved in normal rearing behavior and that lesion-induced alterations in responsiveness to some forms of stimulation may play a modulatory role in reduced rearing.