Corticotropin-releasing factor modulates defensive-withdrawal and exploratory behavior in rats.

The role of corticotropin-releasing factor (CRF), an endogenous neuropeptide, in modulating species-typical responses was examined in an unfamiliar open field containing a small chamber. Rats placed in this small chamber spent most of their time withdrawn in it. However, rats given an icv injection (20 μg) of α-helical CRF(9–41), a CRF receptor antagonist, emerged from the chamber and explored the unfamiliar open field. Results of additional studies with vehicle-treated rats suggest that reexposure reduces the threatening impact of an unfamiliar open field. CRF (300 ng) injected centrally, but not peripherally, before reexposure to the test environment significantly reduced exploration in the open field and increased a pattern of defensive-withdrawal into the chamber. Data suggest that whether defensive-withdrawal or exploratory behavior is exhibited may depend on CRF actions in brain systems that mediate the perception of threat in the environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of previous experience in the male rat's reaction to odors from group and alien conspecifics.

Observed male Long-Evans rats which had cohabited with ovariectomized females for 40 days for their reactions toward the odors from group vs. alien conspecifics. Under conditions where males were kept naive by not rendering their group females receptive, males preferred the odors from group males and females to those of aliens. Under conditions where males were permitted sexual experience, males failed to respond preferentially between group and alien males, and between both receptive and nonreceptive group and alien females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Male mouse (Mus musculus) attraction to airborne urinary odors of conspecifics and to food odors: Effects of food deprivation.

Five experiments demonstrated that 112 male mice were strongly attracted to the urinary odors of females, and that male urinary odors were considerably less attractive. The strong attraction to female urinary odors did not require that the males have postweaning experience with females. Males with continuous access to food and water were much more strongly attracted to female urinary odors than to the airborne food odors. Female urinary odors remained more attractive than food odors after 24-hr food deprivation, and only after 48-hr deprivation did the attractiveness of food odors approximate that of female urine. Although 48-hr food deprivation appeared to equalize the attractiveness of urinary and food odors, this regimen did so not by diminishing the attractiveness of female urine but rather by increasing the attractiveness of food odors. It is argued that the attraction that male mice exhibited to female urinary odors in this odor-testing apparatus reflected, at least in part, a biologically important precopulatory communication system. (29 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Trading behavior between conspecifics in chimpanzees, Pan troglodytes.

Bartering of commodities between individuals is a hallmark of human behavior that is not commonly seen in other species. This is difficult to explain because barter is mutually beneficial and appears to be within the cognitive capabilities of many species. It may be that other species do not recognize the gains of trade, or that they do not experience conditions (e.g., low risk) in which barter is most beneficial. To answer these questions, the authors instituted a systematic study of chimpanzees’ ability to barter with each other when doing so materially benefited them. Using tokens derived from symbols they had used since infancy, pairs of adult chimpanzees (Pan troglodytes) could trade between themselves to obtain tokens needed to get foods. Chimpanzees flexibly used the tokens to obtain foods from an experimenter; however, they did not spontaneously trade with their partner. After extensive training, chimpanzees engaged in accurate trade behavior as long as an experimenter enforced the structure of the interaction; however, trade between partners disappeared when this enforcement was removed. The authors discuss possible reasons for these findings as well as implications for the evolution of barter across the primate lineage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The platelet-activating factor antagonist BN 52021 attenuates hypoxic-ischemic brain injury in the immature rat

Platelet-activating factor (PAF) is overproduced in ischemic brain. Although postischemic PAF antagonist administration protects the mature brain in some models, little is known about the effects of PAF antagonists in the immature brain. We hypothesized that the PAF antagonist BN 52021 would attenuate perinatal cerebral hypoxic-ischemic injury. To elicit focal hypoxic-ischemic brain injury, 7-d-old (P7) rats (n = 111) underwent right carotid ligation, followed by 2.5-3.25 h of hypoxia (fractional concentration of inspired O2 = 0.08). BN 52021 neuroprotection was evaluated in three groups of experiments: 1) 25 mg/kg/dose, 0 and 2 h posthypoxia; 2), 25 mg/kg/dose immediately before and 1 h after hypoxia; and 3) posthypoxia-ischemia treatment with BN 52021 12.5, 25, or 50 mg/kg/dose in 2 doses 0 and 2 h after hypoxia. All experiments included concurrent vehicle-injected controls. To quantitate severity of injury, bilateral regional cross-sectional areas (groups 1 and 2) or hemisphere weights (group 3) were evaluated on P12. Both pre- and posthypoxic treatment with BN 52021 (25 mg/kg/dose, two serial doses) decreased the incidence of cerebral infarction from 90% to about 30% (p < 0.02, Fisher's exact test). Measurement of cross-sectional areas confirmed neuroprotection and indicated some benefit of pre- over posthypoxic-ischemic treatment in hippocampus and cortex. Over the dose range tested, the neuroprotective effect of BN 52021 administration was not dose-dependent. In contrast, BN 52021 did not attenuate N-methyl-D-aspartate-induced hippocampal excitotoxic injury in P7 rats. Either prophylactic or "rescue" administration of PAF antagonists decreases the incidence and severity of brain injury associated with an episode of perinatal cerebral hypoxia-ischemia.     

Effects of chronic haloperidol and intermittent cocaine administration on behavior elicited by apomorphine.

Relatively little is known about the behavioral or neurophysiological effects resulting from the concurrent administration of haloperidol and cocaine. To investigate this drug interaction the effects of chronic, daily administration of haloperidol, intermittent cocaine injections, or the combination of both drug treatments on locomotion and stereotypy elicited by apomorphine in rats (Rattus norvegicus) were compared. The results indicated that, in comparison to treatment with either drug alone, the combination of daily haloperidol and intermittent injections of cocaine produced unique behavioral effects. Rats coadministered both drugs exhibited significant increases in apomorphine-induced locomotion that were maintained throughout the 64 days following suspension of drug treatment. These results are discussed in terms of the possible neurophysiological mechanisms underlying the observed behavioral changes and are related to the consequences of psychostimulant abuse in human neuroleptic treated populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of stimulation parameters on behavior elicited by stimulation of the hypothalamic defense area.

Elicited agonistic behavior by stimulating the ventromedial hypothalamus of 22 domestic cats. 12 different behavioral components were rated separately. Behavioral alerting, mydriasis, retraction of ears, piloerection, hissing, and protrusion of claws were the most characteristic components. The parameters of the stimulus were shown to be important determinants of the nature of the behavior. Results suggest that either discrete central neural circuits for the different components of agonistic behavior are diffusively organized within the ventromedial hypothalamus, or the components result from a general activation of neurons subserving discrete fixed-action patterns, the resultant behavior being determined by different factors, such as the intensity of the activation. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reported physical symptoms elicited by unpredictable events and the Type A coronary-prone behavior pattern.

Hypothesized that unpredictable aversive events are causally linked to physical symptom reporting and that the Type A coronary-prone behavior pattern affects symptom reporting, such that Type A individuals fail to report symptoms when they expect to continue working on a task as compared to when they believe they have completed it. In the present study, 120 Type A and Type B female undergraduates (classified by scores on the Jenkins Activity Survey for Health Prediction) reported symptoms either at the end or in the middle of listening to unpredictable, predictable, or ambient noise in the laboratory. Unpredictable noise produced more symptom reporting than predictable noise, which in turn produced more symptom reporting than the ambient noise; Type A Ss reported fewer symptoms in the middle of the task than at the end, whereas Type Bs did not. Thus, both hypotheses were confirmed. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physiology of drinking elicited by eating.

Notes that much of normal drinking occurs around mealtime and that little is known about the physiological mechanisms involved, despite the identification of neurological substrates and physiological mechanisms for drinking in response to homeostatic deficit. The present author discusses the course of ingested food along the gastrointestinal tract, where food elicits a neuroendocrine cascade of events with the potential for mobilizing drinking. This perspective helps to identify histamine, and perhaps insulin and serotonin, as serving vagally mediated mechanisms that can elicit drinking around mealtime to preclude homeostatic imbalance. The experimental study of how normal drinking behavior ensures homeostasis by precluding homeostatic imbalance has the advantage of promising to enrich, rather than to damage, the status of homeostasis as a guiding principle for understanding the neurobiology of behavior. The concept would be enriched because it would become clear that cognitive functions such as learning, remembering, and planning one's behavior at times guarantee homeostasis and therefore prevent the necessity of a rapid behavioral response to repair the physiological emergency of a homeostatic deficit. (3? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioning of relative frequency of sniffing by rabbits to odors.

Developed and evaluated an automated procedure for sniff detection in 4 experiments with 21 adult New Zealand white rabbits. The sniff was identified by a brief episode of increased respiratory rate, usually with a well-defined time of onset. It was detected against the background of respiratory activity in Ss simply, reliably, and noninvasively by statistical evaluation of digitized pneumograph records. The basal rate of exploratory sniffing was controlled by familiarization. Upon conditioning to olfactory cues, the rate of sniffing for CS+ increased sharply above the basal rate during the 1st trials and was maintained at high levels by continued reinforcement. During extinction with discrimination between olfactory cues, the rate for CS– fell sharply at first and then more slowly toward the basal rate. With pseudoconditioning, Ss responded to an unpaired odor after several sessions; the rates of response acquisition and extinction and the maintained level of responding were lower than with a paired odor in classical delayed conditioning, and the response was not discriminative in respect to another novel odor given during extinction. The sniff displayed a prominent sensory bias for olfactory cues. The relative frequencies of sniffing and respiratory slowing were measured as CRs by screening procedures with a small computer. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modulation of appetitively and aversively motivated behavior by the kappa opioid antagonist MR2266.

MR2266 (MR), an opioid antagonist that binds to kappa and mu receptors, was examined for its ability to influence the aversively motivated behaviors conditioned by electric shock and the drinking induced by water deprivation or the availability of a palatable saccharin/glucose solution. The intraperitoneal (ip) and intracerebroventricular (icv) administration routes were contrasted. After both ip and icv administration, MR was able to reverse conditional analgesia as measured by the formalin test. MR enhanced the Pavlovian conditional freezing response when administered icv prior to shock exposure but reduced freezing if given ip prior to shock. A related benzomorphan-derived opioid antagonist, MR1452, also reduced freezing when given ip prior to shock. MR2266 was a potent antidipsogenic agent when administered ip but had no such effect when administered icv. It is concluded that separable opioid systems are involved in the modulation of appetitively and aversively motivated behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exogenous androgen activates female behavior in noncopulating, prenatally stressed male rats.

Male copulatory behavior was severely impaired in 39 male offspring of Sprague-Dawley female rats stressed during pregnancy. This deficiency persisted even after castration and prolonged treatment with testosterone propionate and after exposure to electric skin shock. However, androgen treatment effectively activated female lordotic behavior in a large percentage of prenatally stressed males but not in any controls and in only a negligible number of postnatally stressed males. Although prenatal stress demasculinizes and feminizes behavior, no modifications of reproductive morphology were detectable. It is suggested that prenatal stress alters normal sexual behavior differentiation by attenuating testosterone secretion from the fetal testes. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intracerebroventricular infusion of the galanin antagonist M40 attenuates heterosexual partner preference in ferrets.

Gonadectomized, estradiol-treated male and female ferrets (Mustela furo) received intracerebroventricular (icv) infusions of 4 doses of the galanin receptor antagonist M40 or galanin and were allowed to approach breeding male or female ferrets that were placed behind wire mesh barriers in the goal boxes of a T maze. After icv infusion of saline, subjects strongly preferred to approach stimulus ferrets of the opposite sex. Male and female subjects approached these preferred stimulus animals on significantly fewer trials after icv infusion of the 2 highest doses of M40, whereas this drug failed to affect males' coital behavior in separate tests with an estrous female. Endogenous galanin may facilitate neural reward mechanisms that control heterosexual partner preference in both sexes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory recognition of conspecifics by domestic Norway rats

In order to learn more about their ability to recognize one another via olfaction, domestic male rats were given a series of preference tests in which pairs of odors from male conspecifics were presented. Both immature and mature males prefer (p less than .05) the odor from immature strangers over that from immature cage mates but are indifferent to the ordors from mature strangers versus cage mates. Both immature and mature males prefer (p less than .05) the odor from mature novel cage mates over that from mature cage mates to which they are temporarily habituated but are indifferent to the odors from immature novel versus familial cage mates. Mature males prefer (p less than .08) the odor from a cage mate over the subject's own odor, and they prefer (p less than .01) their own odor over no odor. Under certain conditions, male rats can discriminate between the odors from (a) strangers versus cage mates, (b) two cage mates, and (c) their own body versus a cage mate.     

Development of social roles in elicited and spontaneous behavior during the preschool years.

Two experiments tested 108 children (1.5–7.5 yrs old) on a predicted, 8-step sequence of the development of social roles. Performance on this sequence was related to 2 measures of more spontaneous behavior. Nearly all Ss fit the predicted sequence. By 2 yrs of age, most Ss made a doll act as an independent agent. The majority of 3-yr-olds made a doll carry out several behaviors fitting the role of doctor. At age 4 or 5, most Ss developed the capacity to show a social role, making a doctor doll interact with a patient doll. The intersection of social roles for 2 agents appeared at about age 6: A man doll could be both doctor and father to a patient who was also his daughter. In their spontaneous behavior, early preschoolers almost always showed the highest step that they were capable of, but beginning with the step for social roles, late preschoolers seldom showed their highest step. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex-specific regulation of marking behavior by sex hormones and conspecifics scent in tree shrews (Tupaia belangeri)

The question of whether the changes in telomerase activity and/or the alteration of the p53 gene are involved in the development of oligo-astrocytomas induced by N-ethyl-N-nitrosourea (ENU) in rats was addressed. Telomerase activity levels of oligo-astrocytomas, including early neoplastic lesions, were significantly increased as compared to the normal controls, correlating with the degree of malignancy. In contrast, no mutations of p53 exons 5-7 were found in early neoplastic lesions or oligo-astrocytomas. These results indicate that the activation of telomerase occurs during astrocytoma carcinogenesis and contributes to the development of brain tumors, but the alterations of p53, at least on exons 5-7, may not be involved in this process.     

Intermale fighting affected by home-cage odors of male and female mice.

Conducted 3 experiments to test the hypothesis that male mice can produce an aggression-inhibitory or facilitory odor under varying conditions of social stimulation. In Exp I, 25 male fighter mice fought 25 castrated opponents more vigorously in soiled home cages of either single or stable groups of male mice than they did in clean cages. Fighting was also stimulated in cages briefly occupied by other pairs of fighting mice. It is concluded that the release of aggression-promoting home-cage odors by male mice is not necessarily a consequence of social instability and that they are of urinary, rather than preputial, origin. In Exp II (with 21 fresh Ss) and Exp. III (with 30 Ss from Exp I), odors deposited by either single or groups of female mice greatly reduced fighting, indicating that their urinary aggression-inhibiting pheromone is effective after deposition upon the home environment. Testosterone propionate implants abolished the females' inhibitory pheromone and did so independently of their enlarged preputial glands. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A hierarchical factor analysis of foreman behavior.

"Ratings of [141] industrial foremen were made using a check list. Scores on 18 variables representing six hypothesized aspects of supervisory behavior were factor analyzed using the hierarchical factor model. A detailed explanation of the application of the hierarchical model is given. In terms of the present data, four factors were found, one a general or 'halo' factor and three interpretable factors. These were described in terms of their meaning and variance. The factors were designated as Social Relations, Technical Job Knowledge, and Administrative Skills and are similar to several previously reported. It is concluded that the hierarchical factor model is a useful technique for the analysis of intercorrelations of trait ratings." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of tectotomy and decerebration on spontaneous and elicited behavior of tadpoles and juvenile frogs.

The performance of tadpoles and juvenile frogs on a battery of behavioral tests was compared before and after tectotomy, removal of the telencephalon (decerebration), tectotomy in conjunction with decerebration, or before and after a sham operation. Posture, righting, and vestibular responses were not altered by any of the lesions at either stage of development, and gross motor abilities were not impaired. Cutaneous reflex thresholds of juveniles were reduced by removal of the tectum or the telencephalon to near-larval levels. All of the lesions abolished characteristic defensive responses of juveniles (freezing) and resulted in hyperreactivity to a wide variety of stimuli. Tectotomy and decerebration of larvae each resulted in a 50% reduction in spontaneous locomotion and, in combination, virtually eliminated spontaneous locomotion. None of the lesions had any effect on the level of spontaneous locomotion of juveniles, but activity elicited by the novelty of the testing environment was eliminated in decerebrate subjects. Neither nystagmus nor optokinetic locomotion was affected by any of the lesions at either stage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)