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PubMed1997

Early NMDA receptor blockade impairs defensive behavior and increases cell proliferation in the dentate gyrus of developing rats.

These studies were conducted to determine whether (a) early N-methyl-D-aspartate (NMDA) receptor blockade impairs defensive behavior and (b) a relationship exists between defensive behavior and the production of granule cells in the dentate gyrus. Rat pups were treated with different doses of the NMDA receptor antagonist CGP 43487 on postnatal day (P) 5, and their behavior was observed following exposure to an unfamiliar adult male rat, a potential predator, on P13, P20, and P30. A dose-dependent impairment in freezing behavior was observed in rat pups treated with NMDA receptor antagonist on P13, P20, but not P30. Moreover, a dose-dependent increase in the number of (3)H-thymidine-labeled cells in the dentate gyrus was detected following CGP 43487 treatment, suggesting that an inverse relationship exists between cell proliferation and freezing behavior in rat pups following NMDA receptor blockade.

2-Amino-5-phosphonovalerate↗
PubMed2003

Overcome toxic management.

Ineffective, ill-tempered managers hurt employee morale and productivity. Learn what behaviors characterize toxic managers, how they damage an organization, and how to lessen their impact.

Agonistic Behavior↗
PubMed1992

The role of the cortex in play fighting by rats: developmental and evolutionary implications.

Play is a distinctive behavior of young mammals, especially mammals with a well-developed forebrain. For this reason it is thought that there may be a relation between forebrain evolution and highly elaborated play behavior. This study investigated the contribution of the cortex to play behavior by comparing play in control and neonatally decorticated rats (Rattus norvegicus). Play fighting in rats involves the combination of attack by one rat and defense by the recipient, with pinning arising when specific patterns of defense are used. Whether paired with another decorticate or with an intact pairmate, decorticates attacked pairmates as frequently as did intacts, and they were just as likely to defend against playful attacks as were intacts. Where decorticates differed from intacts was on a measure of pinning, in which one rat stands over a supine partner, decorticate rats displayed a reduction of 50% relative to control rats during the juvenile stage in which play is most pronounced (days 25 to 40). Juvenile decorticate rats adopted types of defensive responses which were less likely to result in the pinning configuration. Thus, a reduced pinning frequency reflects an altered pattern of defense, not a reduced level of play fighting. Rather, the decorticate patterns of defense were typical of those defensive responses displayed by adult rats. That is, decorticate juveniles exhibit a precociously mature pattern of playful defense. As intact controls mature, they come to resemble the decorticates in their defensive responses, and hence the difference in pinning frequency between decorticate and intact pairs diminishes. This suggests that the cortex may inhibit the escalation of defense in juveniles and thus promote prolonged ventral-ventral contact during play fighting. The results further suggest that the cortex is involved in the development of adult behavioral skills by facilitating juvenile play.

Aggression↗
PubMed1976

Vocalizations and their behavioral contexts in the tamarin Saguinus fuscicollis.

The characteristic calls of Saguinus fuscicollis are described and illustrated with sound spectrograms. Each call type and its associated behavior is listed together with motor and vocal responses usually observed for a given context. Many of the call types are highly specific to social contexts while others appear to reflect changes in excitation level. Call types form two categories when related according to their acoustic structural similarity. Information in the 'group vocabulary" is discussed under five functional categories: spatial cohesion; alerting; aggressive behavior; infant calls, and adult vocalization during infant calls.

Age Factors↗
PubMed1993

Antinociception induced by alpha-2-adrenoceptor agonists, with special emphasis on medetomidine studies.

Alpha-2-adrenoceptor agonists can activate varying antinociceptive mechanisms depending on the dose and the route of administration, although the main site for their antinociceptive effect in physiological pain conditions seems to be the spinal dorsal horn. In this paper the investigations on the underlying mechanisms are reviewed, with particular emphasis on novel studies using a highly selective and potent alpha-2-adrenoceptor agonist medetomidine. In behavioral studies alpha-2-adrenoceptor agonists, including medetomidine, produce antinociception following systemic administration or local application to the spinal cord. Following systemic administrations the antinociceptive effect at subanesthetic doses in physiological pain conditions is weak and the affective-motivational component of pain is more sensitive to suppression than sensory-discriminative aspect of pain. Electrophysiological studies at the spinal cord level indicate that alpha-2-adrenoceptor agonists suppress the responses of the pain-relay neurons both due to pre- and postsynaptic spinal cord level mechanisms following systemic or intrathecal drug administration. The antinociceptive effect at the spinal cord level is selective, since non-nociceptive signals are not attenuated. According to electrophysiological single neuron recordings, nociceptive signals at supraspinal levels are more sensitive to antinociceptive effects of systemically administered alpha-2-adrenoceptor agonists than nociceptive signals at the spinal cord level. However, according to immunocytochemical imaging of immediate early gene response to noxious stimulation, medetomidine strongly suppresses responses at the spinal cord level already following a systemic dose (100 micrograms/kg i.p.) which is not enough to produce a significant suppression of spinally-initiated nocifensive tail reflexes nor the electrophysiologically recorded responses to nociceptive spinal neurons. Thus, the higher sensitivity of supraspinal neuronal responses and their behavioral correlates to the antinoceptive effect of medetomidine obviously reflects the cumulative effect of medetomidine at several areas along the polysynaptic pathway to the rostral parts of the brain. Paradoxically, the response of immediate early genes in the medial thalamic neurons is only slightly, influenced by antinociceptive doses of medetomidine. Alpha-2-adrenoceptors have significant interactions with other receptors (e.g. opioid, serotonin and muscarine) in producing antinociception at the spinal cord level.

Adrenergic alpha-Agonists↗
PubMed1984

[Dopamine sensitivity of brain-induced behavior after repeated administration of dopamine agonists and antagonists].

Comparative investigations were carried out on dopamine sensitivity, as judged by the rotational behavior of rats, of different nuclear areas of the central nervous system following repeated application of dopaminergic agonists, or the dopamine antagonist, haloperidol. In the mesolimbic area and in the Nucleus caudatoputamen, repeated pretreatment with amphetamine alone or in combination with another agonist did not result in a change of sensitivity to dopamine. In contrast, dopamine sensitivity of these target areas increased strongly by repeated pretreatment with haloperidol. Pretreatment with dopaminergic agonists distinctly increased the rotation intensity following dopamine injection into the Globus pallidus and Substantia nigra, whereas haloperidole pretreatment reversed the rotational direction after pallidally injected dopamine, and left unaffected the sensitivity of the Substantia nigra. Thus, repeated treatment with dopaminergic agonists produces different patterns of sensibilization. This does lend support to the hypothesis that behavioral facilitation and dopaminergic supersensitivity are mediated differently.

Amphetamine↗
PubMed1994

Hippocampal asymmetry in the behavioral responses to the 5-HT1A receptor agonist 8-OH-DPAT.

The present study examined the behavioral responses of rats to unilateral and bilateral injections of the selective serotonin 1A (5-HT1A)-receptor agonist 8-hydroxydipropylaminotetralin hydrobromide (8-OH-DPAT) 1 microgram into the hippocampal CA1 area of male Wistar rats. 8-OH-DPAT increased locomotor activity, which was most pronounced with injections into the left hippocampus. The agonist impaired learning and memory (shuttle-box), especially when injected into the right hippocampus. The elevated plus-maze experiments showed that neither left nor right nor bilateral hippocampal injections of 8-OH-DPAT produced any anxiogenic effect. However, with Vogel's conflict test, right injections of 8-OH-DPAT produced anxiety. The present study has revealed hippocampal asymmetry in the behavioral responses to the 5-HT1A-receptor agonist 8-OH-DPAT.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2003

The neural basis of dominance hierarchy formation in crayfish.

Fifty years of study of the nervous system and behavior of crayfish have revealed neural circuits for movements that are similar to those seen during formation of a dominance hierarchy. Given this background, it is of interest to ask what is understood about the neural substrates of dominance hierarchy formation. Here we will consider the social behavior that crayfish display in the wild and in the laboratory, and its relationship to movements released by activation of specific neural circuits. We will consider how these movements might be knit together to produce the behavior patterns that are characteristic of dominant and subordinate animals.

Agonistic Behavior↗
PubMed1986

Aggression during morphine withdrawal: effects of method of withdrawal, fighting experience, and social role.

Offensive and defensive components of aggressive behavior were determined in resident and intruder mice. Withdrawal aggression was measured after the removal of a subcutaneous morphine pellet or after precipitation by naloxone in naive mice and after removal of a morphine pellet in mice with prior fighting experience. In naive mice, removal of a morphine pellet led to increases in attack bites and threats but naloxone-precipitated withdrawal led to decreases in these behaviors and to increases in defensive posturing, escape attempts and vocalizations. Prior fighting experience abolished the enhanced attack behaviors of resident mice following morphine pellet removal, but led to heightened defensive behavior in intruder mice. The behavior of intruder mice appeared more sensitive to naloxone administration than the behavior of resident mice; naloxone influenced not only intruder defensive behavior, but also other non-aggressive behaviors. The social role of the drug recipient and his prior history of aggressive behavior are important determinants of morphine and naloxone effects on aggression.

Aggression↗
PubMed1992

Interstrain aggression in hypertensive and/or hyperactive rats: SHR, WKY, WKHA, WKHT.

Four inbred rat strains, all derived from Wistar-Kyoto (WKY) rats, express hypertension and hyperactivity in all combinations: SHRs have both traits, WKYs have neither, WKHAs are hyperactive/normotensive, and WKHTs are hypertensive/normoactive. Rats of the four strains were tested for aggression, at one time only, by pairing subjects of same sex, same age, but different strain, in a novel arena, i.e., on neutral ground, for three consecutive, 5-min observation periods. Total aggression scores were highest in females, highest in the first 5-min period, and lower at 7-9 months than at younger ages. Allogrooming was more frequently observed than other types of aggression, such as attacks, mounts, aggressive postures, and blocks. Allogrooming scores were significantly elevated in the hypertensive strains, especially WKHT, and very low in the hyperactive strains, especially WKHA. The other forms of aggression were significantly higher in females with hyperactivity. It was concluded that interstrain aggression, as seen in SHRs and WKYs, is differentially expressed by two new strains genetically derived from them. Furthermore, no one strain among these four expresses all components of the behavioral responses seen in this form of aggression.

Aggression↗
PubMed1984

Neuropeptides and social behavior of rats tested in dyadic encounters.

The effects of various neuropeptides on social behavior was studied in a test procedure in which 7-day isolated animals were tested together with non-isolated partners in dyadic encounters. The short-term isolation procedure increased the frequency and duration of social activities of the rats, but hardly affected non-social explorative behaviors of the animals. Systemic injection of certain neuropeptides, i.c. prolyl-leucyl-glycinamide (PLG), thyrotropin releasing hormone (TRH) and the ACTH 4-9 analog ORG 2766, reversed the isolation-induced increase in social activity, similarly as previously observed with antidepressant drugs. Subcutaneous treatment with beta-endorphin, alpha-endorphin and des-Tyr-gamma-endorphin increased social interactions in 7-day isolated animals. beta-Endorphin enhanced social behavior of non-isolated rats as well, whereas gamma-MSH decreased the social interactions of these animals. Both peptides affected especially social contact behavior. The potent action of beta-endorphin suggests that this peptide and opioid systems may play a physiological role in social behavior. It is proposed that a possible functional antagonism between ACTH-like peptides, especially gamma-MSH, and beta-endorphin may operate in social behavior. The action of the peptides may be rather specific for social behavior, since none of the neuropeptides affected non-social explorative behaviors of the rats during the social interaction test.

Adrenocorticotropic Hormone↗
PubMed2006

Test- and behavior-specific genetic factors affect WKY hypoactivity in tests of emotionality.

Inbred Wistar-Kyoto rats consistently display hypoactivity in tests of emotional behavior. We used them to test the hypothesis that the genetic factors underlying the behavioral decision-making process will vary in different environmental contexts. The contexts used were the open-field test (OFT), a novel environment with no explicit threats present, and the defensive-burying test (DB), a habituated environment into which a threat has been introduced. Rearing, a voluntary behavior was measured in both tests, and our study was the first to look for genetic loci affecting grooming, a relatively automatic, stress-responsive stereotyped behavior. Quantitative trait locus analysis was performed on a population of 486 F2 animals bred from reciprocal inter-crosses. The genetic architectures of DB and OFT rearing, and of DB and OFT grooming, were compared. There were no common loci affecting grooming behavior in both tests. These different contexts produced the stereotyped behavior via different pathways, and genetic factors seem to influence the decision-making pathways and not the expression of the behavior. Three loci were found that affected rearing behavior in both tests. However, in both contexts, other loci had greater effects on the behavior. Our results imply that environmental context's effects on decision-making vary depending on the category of behavior.

Agonistic Behavior↗
PubMed1986

The gerbil: a unique model for research on aging.

The Mongolian gerbil (Meriones unguicultatus) is suggested as a model for aging research because of its unique physiological attributes, ease of handling, and because of data previously collected. Factors that demonstrate the gerbils' suitability in fulfulling practical and scientific considerations important in determining a model for aging research are listed. Additionally, several unique physiological attributes of gerbils are described. Based on these attributes and on review of research in gerbils, it is suggested that gerbils can serve as animal models for behavioral and biological processes, and for normative and pathological aspects for aging.

Adrenal Cortex↗
PubMed1995

Impulsivity and the initiation of fights in children with disruptive behavior disorders.

This study examined whether children who initiate physical fights are impulsive as measured by a continuous performance test. A series of 111 7-13-year-old psychiatric patients were diagnosed using DSM-III-R criteria and divided according to whether they showed a persistent pattern of initiating physical fights. Children who initiated fights were impulsive irrespective of whether ADHD was present or not, although ADHD was also associated with increased impulsivity. Oppositional-defiant disorder and conduct disorder diagnoses were not associated with impulsivity. These findings are discussed in terms of an underlying impulsive personality trait and its possible relationship to outcome in children with disruptive behavior disorders.

Adult↗
PubMed2007

Predicting the frequency of food-related agonism in white-faced capuchin monkeys (Cebus capucinus), using a novel focal-tree method.

Food abundance and distribution have played a central role in the conceptual theory of primate socioecology [Janson, Behaviour 105:53-76, 1988; Isbell, Behavioral Ecology 2:143-155, 1991; Sterck et al., Behavioral Ecology and Sociobiology 41:291-309, 1997; van Schaik, In: Standen V, Foley RA, editors, Comparative Socioecology. Oxford: Blackwell. p 195-218, 1989]. This theory predicts that agonistic ("contest") competition should occur when food is distributed in discrete, defensible patches; in contrast, when food sources are distributed uniformly or randomly, non-agonistic ("scramble") competition is expected. Primatologists usually measure resource density and patchiness from a botanical perspective, ignoring the biology of the animal being studied. Such an approach may be irrelevant in terms of how animals view the dispersion of resources. Using a novel focal-tree method that measures resource availability on a scale that is both spatially and temporally relevant to the animal under investigation, we take a cost-benefit approach to predict the frequency of food-related agonism in white-faced capuchin monkeys (Cebus capucinus) from 11 ecological and social variables. We retained four variables in the regression model: two representing the opportunity for aggression (i.e., feeding bout length and the number of feeding adult females), and two representing opportunity costs (i.e., fruit abundance and the number of potential feeding sites in the focal tree). The results of this study indicate that the amount of food-related aggression in white-faced capuchins can be predicted by variables representing the costs and benefits of contesting a food resource.

Agonistic Behavior↗
PubMed1990

Hypothalamic sites of progestin action on aggression and sexual behavior in female Syrian hamsters.

The effects of intracranial implants of the synthetic progestin, promegestone (R5020), on aggression and sexual behavior were examined in female Syrian hamsters. Ovariectomized female hamsters showed high levels of aggression and no lordosis towards stimulus male and female hamsters, both prior to and after estradiol benzoate treatment. Forty-six hr after estradiol treatment (10 micrograms SC), 10% crystalline promegestone was applied bilaterally (27 ga cannulae) to the ventromedial hypothalamus. When tested 5-7 hr later, these animals had a significant reduction in the rate of attacks towards females, with no lordosis responding to a male. In contrast, promegestone in the caudal anterior hypothalamus activated low levels of lordosis, yet these females maintained high levels of aggression towards stimulus females. Females receiving promegestone in the rostral anterior hypothalamus, and control females receiving intracranial cholesterol, maintained high levels of aggression and no lordosis. Estradiol treatment alone enhanced pelvic movements in response to experimenter-applied perineal stimulation in a majority of females (18/22 compared with 4/22 prior to estradiol injection), with intracranial treatments having no further effect. These results indicate that progestins act on aggression and sexual behavior in female Syrian hamsters at different hypothalamic loci.

Aggression↗
PubMed1994

Flight-elicited attack and priming of aggression in nonaggressive hamsters.

We report a technique for inducing attack in apparently nonaggressive hamsters that takes advantage of several behavioral effects: (a) the vigorous flight that repeatedly defeated hamsters display in the presence of conspecifics, (b) the potent, attack-eliciting properties of such flight, and (c) attack priming (i.e., aggressive arousal from exposure to an initial stimulus animal carries over to exposure to a second one). Resident hamsters that had consistently failed to attack nonfleeing intruders were found to readily attack intruders that did flee. But repeated exposure to the fleeing intruders alone did not induce long-term changes in aggressiveness. However, flight-elicited attack did successfully prime attack onto nonfleeing intruders presented immediately after the fleeing intruder was removed. Repeating such priming transfer trials induced long-term changes in the formerly nonaggressive subjects. We conclude that this is an effective procedure for inducing aggression that would be preferred when it is important to avoid exposing subjects to aversive stimuli. The changes in behavior that we observed seem to reflect heightened motivational levels.

Aggression↗