Mating behavior: facilitation in the female rat after cortical application of potassium chloride

Mating behavior in ovariectomized female rats treated with estrogen can be greatly enhanced by subcutaneous injections of progesterone. Application of potassium chloride to the cortex of females previously treated with estrogen can also induce greatly increased sexual receptivity as indicated by the lordosis response. This facilitation of mating behavior by a treatment known to cause functional decortication suggests that mechanisms mediating female mating behavior are under tonic inhibition by an inhibitory system which involves the cerebral cortex.     

Observational learning and social facilitation in the rat

Learning by rats was facilitated when response-relevant cues were provided by other rats; learning increased as a function of number of cues provided. These results suggest that rats can learn by imitation. Learning by rats that observed conspecifics not emitting response-relevant cues was retarded compared to learning by rats that did not observe conspecifics. This indicates that a conspecific's presence can also inhibit learning, a result consistent with social facilitation theory.     

Maternal behavior in wolf spiders: the role of abdominal hairs

Newly emerged, juvenile wolf spiders do not settle on clothed or shaved areas of their mother's abdomen until after a period of days. Spiny, knobbed hairs, peculiar to adult female lycosids, apparently provide the stimulus and means for attachment by the inner layer of spiderlings. Innervated long, smooth hairs are mechanoreceptors which probably serve in other aspects of brood care.     

Synaptic facilitation: long-term neuromuscular facilitation in crustaceans

Continuous stimulation at frequencies equal to or greater than 5 hertz for 20 to 30 minutes results in a two- to fivefold increase in the amplitudes of excitatory postsynaptic potential recorded from certain stretcher and opener muscles of decapod crustaceans. This long-term facilitation appears to result from an accumulation of sodium ions within the nerve terminals. It persists for at least 1 hour after stimulation has stopped.     

Maternal behavior in the domestic cock under the influence of alcohol

When normal male domestic chickens were given a single dose of grain alcohol and then exposed to newly hatched chicks, they, assumed maternal behavior. The same behavior can be elicited by the admniinistration of prolactin, but the results of these experimens suggest that maternal behavior in tlhe cock is not excliusively dependent on hormonal mechanisms.     

Estrous cycle in the rat: effects on self-stimulation behavior

The performance of female rats, in pressing a bar for electrical stimulation of the hypothalamus, changes during the estrous cycle. Highest barpressing rates accompany the appearance of vaginal cornification. This increase is not an artifact of increased spontaneous activity at estrus, although the factors underlying these changes in activity may also mediate the changes in self-stimulation behavior.     

Evidence for addiction-like behavior in the rat

Although the voluntary intake of drugs of abuse is a behavior largely preserved throughout phylogeny, it is currently unclear whether pathological drug use ("addiction") can be observed in species other than humans. Here, we report that behaviors that resemble three of the essential diagnostic criteria for addiction appear over time in rats trained to self-administer cocaine. As in humans, this addiction-like behavior is present only in a small proportion of subjects using cocaine and is highly predictive of relapse after withdrawal. These findings provide a new basis for developing a true understanding and treatment of addiction.     

Sexual behavior: ultrasonic postejaculatory song of the male rat

During the refractory period that follows ejaculation, the male rat regularly emits 22-kilohertz vocalizations. These cease after about three-fourths of the total period has elapsed, and this corresponds to an "absolute refractory period" during which the male cannot spontaneously initiate copulation. Similar 22-kilohertz vocalizations occur in other social contexts, and in general they appear to be desist-contact signals.     

Nonhormonal basis of maternal behavior in the rat

Rats were tested for induction of maternal behavior by exposing them to young pups continously for 10 to 15 days. Nonpregnant intact, ovariecto-mized. and hypophysectomized females were studied, as well as intact and castrated males. Nearly all the animals exhibited the four main items of maternal behavior and there were only minor differences in the latencies for the onset of maternal behavior among the various groups. It is concluded that all rats have a basic level of maternal responsiveness which is independent of hormonal stimulation.     

Inhibitory centers in sexual behavior in the male rat

Small lesions placed near the diencephalic, mesencephalic junction, in either the lateral or medial mammillary region, resulted in an increase of copulatory behavior. This increase was expressed both by increased numbers of copulation plugs formed per 14-day interval and by increased percentage of days on which copulation occurred. Inhibitory structures thus form an essential part of the circuitry involved in mediation of sex behavior in the male.     

Operant behavior changes norepinephrine metabolism in rat brain

Rats performing a lever-pressing response for water reward in an operant situation, when compared with control groups, showed an increase in brain norepinephrine metabolism. One control group included rats which were handled and deprived of water in the same way as the experimental group but were not trained to perform the operant task. We conclude that performance in an operant situation affects norepinephrine metabolism.     

Norepinephrine-sensitive adenylate cyclases in rat brain: relation to behavior and tyrosine hydroxylase

Responses of norepiniephrine sensitive adeniosinie 3',5'-monophosphate (cyclic AMP)-generating systems in combined midbrain-striatal slices of four rat strains correlate positively with spontaneous behavioral activity and negatively with levels of midbrain and striatal tyrosine hydroxylase. Responses of cerebral cortical norepinephrine-sensitive cyclic AMP systems correlate negatively with spontaneous behavioral activity antd positively with midbrain and striatal tyrosine hydroxylase. Such correlations were not found with responses of the cyclic AMP- generatinlg systems to isoproterenol, adenosine. veratridine or of an adenosne and norepinephrine combination.     

Agnonistic behavior in organized and disorganized cotton rat populations

Agonistic interaction rate is significantly lower in groups of caged cotton rats (Sigmodon hispidus) from naturally occurring organized populations than in groups composed of strangers. Some type of social structure is apparently present between animals sharing a common area under natural conditions. After a 24-hour period, there is no significant difference in the behavior of the two groups, an indication that a social structure is rapidly formed in the disorganized groups.     

Prenatal alcohol exposure alters adult expression of sexually dimorphic behavior in the rat

Saccharin preference and performance in a Lashley III maze were found to be altered in adult male and female rats that had been exposed to alcohol during gestation. Specifically, the sexual dimorphism normally observed in both behaviors was absent in fetal alcohol-exposed animals. The lack of sexual dimorphism appeared to result from a masculinization of the exposed females and a feminization of the exposed males.     

Serengeti migratory wildebeest: facilitation of energy flow by grazing

Dense concentrations of migratory wildebeest leaving the Serengeti Plains in late May 1974 reduced green plant biomass by almost 400 grams per square meter, 85 percent of the initial standing crop. However, this grazing prevented senescence and stimulated net primary productivity of the grasslands. Thomson's gazelles leaving the plains a month later were significantly associated with areas previously grazed by wildebeest, and this association was still evident at the end of the dry season, 6 months later.