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At least 1,441 records · Page 80Linked to original sources
PubMed1991

Effects of mammillary body and mediodorsal thalamic lesions on elevated plus maze exploration.

This study investigates the effects of lesioning the mamillary bodies (MB) or the dorsomedian nucleus (MD) of the thalamus on exploration of an elevated plus maze in mice. Exploration of 'open' and 'enclosed' arms of the maze has been used to evaluate anxiety in rodents. Normal rodents visit the enclosed arms more often than the open ones (innate agoraphobia). As operationally defined, the less the activity in the open arms, the more anxious is the subject. MB-lesioned mice entered the open alleys more often, and spent more time in them, than did controls, whereas the opposite was observed in MD-damaged subjects. It is suggested that, in mice given this task, MB lesions decrease anxiety and that MD lesions increase anxiety.

Animals↗
PubMed2004

Bilateral labyrinthectomy causes long-term deficit in object recognition in rat.

It has been reported that patients with vestibular disorders experience a wide range of cognitive disorders, including memory loss. However, to our knowledge, no study has investigated the contribution of vestibular information to episodic memory in experimental animals using vestibular deafferentation. In the present study, the effects of a complete unilateral or bilateral surgical lesion of the vestibular labyrinths in a spontaneous object recognition task were evaluated in Wistar rats 3 and 6 months following the surgery. We found that rats with bilateral vestibular deafferentation, but not those with unilateral vestibular deafferentation were impaired on the task at both time points. These results suggest for the first time that vestibular information may contribute to non-spatial memory to some extent.

Analysis of Variance↗
PubMed2007

Plasticity in animal personality traits: does prior experience alter the degree of boldness?

Theoreticians predict that animal 'personality' traits may be maladaptive if fixed throughout different contexts, so the present study aimed to test whether these traits are fixed or plastic. Rainbow trout (Onchorhyncus mykiss) were given emboldening or negative experiences in the forms of watching bold or shy individuals responding to novelty or winning or losing fights to examine whether prior experience affected boldness. Bold individuals that lost fights or watched shy demonstrators became more shy by increasing their latency to approach a novel object, whereas shy observers that watched bold demonstrators remained cautious and did not modify their responses to novelty. Shy winners became bolder and decreased their latency to approach a novel object, but shy losers also displayed this shift. In comparison, control groups showed no change in behaviour. Bold fishes given negative experiences reduced their boldness which may be an adaptive response; however, shy fishes may base their strategic decisions upon self-assessment of their relative competitive ability and increase their boldness in situations where getting to resources more quickly ensures they outcompete better competitors.

Adaptation, Biological↗
PubMed2004

Context-dependent effects of CB1 cannabinoid gene disruption on anxiety-like and social behaviour in mice.

Contrasting data were reported regarding the effects of cannabinoids on anxiety and social behaviour in both animals and humans. The cognitive effects of cannabinoids and their interactions with the HPA-axis raise the possibility that cannabinoid effects are context but not behaviour specific. To assess this hypothesis, we submitted CB1 receptor knock-out (CB1-KO) and wild-type (WT) mice to tests, which involved similar behaviours, but the behavioural context was different. The elevated plus-maze test was performed under less and more anxiogenic conditions, i.e. under low and high light, respectively. We also compared the social behaviour of the two genotypes in the resident/intruder and social interaction tests. Both tests represent a social challenge and induce similar behaviours, but involve different contexts. The behaviour of CB1-KO and WT mice was similar under low light, but CB1 gene disruption increased anxiety-like behaviour under the high light condition. CB1 gene disruption promoted aggressive behaviour in the home-cage, whereas it inhibited social behaviour in the unfamiliar cage. Thus, the anxiogenic-like effect was restricted to the more stressful unfamiliar environment. These data suggest that the effects of CB1 gene disruption were context and not behaviour specific. Novelty stress resulted in higher ACTH levels in CB1-KOs than in WTs, which suggests that context dependency occurred in conjunction with an altered HPA axis function. The present data at least partly explain contrasting effects of cannabinoids in different contexts as well as in different species and strains that show differential stress responses and coping strategies.

Adrenocorticotropic Hormone↗
PubMed2006

Distinct patterns of plasticity in prefrontal cortex neurons that encode slow and fast responses to stress.

The prefrontal cortex (PFC) has been implicated in cognitive and affective responses to acute and chronic stress; however, direct evidence for the reactivity or adaptability of PFC neurons to stress is lacking. We followed the unit activity of medial PFC (mPFC) neurons in awake rats during two consecutive exposures to restraint stress or to a non-aversive novel object. The majority (75%) of mPFC neurons had significant responses to the initial restraint that was differentiated into one of three temporal patterns: (i) phasic increase in firing rate during the restraint period, (ii) slow onset increase in firing rate that was sustained for > 2 h after restraint, and (iii) brief bi-phasic responses to initiation and termination of restraint. Exposure to a novel object elicited an exposure-locked phasic response in 40% of the neurons. None of the neurons displayed the sustained activation that was prominent after restraint. A second exposure to the object no longer elicited this phasic response while neurons in the three restraint-responsive groups modified their firing rate during the second restraint in a manner that was specific to their pattern of response to the first restraint. These findings demonstrate that whereas some mPFC neurons respond phasically to novel stimuli irrespective of their aversive nature, a separate population of PFC neurons responds to a stressful stimulus with a sustained increase in firing rate that persists in the absence of that stimulus. These neurons may be a substrate for adaptive responses that are necessary for behavioral modification.

Action Potentials↗
PubMed1991

Motives of childhood firesetters: firesetting characteristics and psychological correlates.

The present study evaluated curiosity and anger as motives among childhood firesetters. Parents of 133 firesetters (ages 6-13) completed the Fire Incident Analysis (FIA) to permit classification of the children as high and low on each of these two primary motives and to document details of the child's most serious incident within the past 12 months. The children were compared on measures of child dysfunction and firesetting history. An effect of Curiosity was found on measures of psychopathology, firesetting risk, and fire involvement, whereas an effect of Anger was found on measures of firesetting risk and the behavioral correlates of individual incidents. The results clarify the role of child motive in understanding firesetting involvement.

Adolescent↗
PubMed1972

Nutritional and environmental interactions in the behavioral development of the rat: long-term effects.

The behavioral effects of early malnutrition and early environmental isolation were observed in male rats. Dietary and environmental manipulations occurred during the first 7 weeks of life, after which followed a 10-week recovery period. On the basis of several different responses, it was found that the behavioral effects of early malnutrition were exaggerated by the environmental isolation. In most cases, the behavioral effects of early malnutrition were completely eliminated by supplying "additional stimulation" early in life. Two theoretical mechanisms are proposed to explain these findings.

Age Factors↗
PubMed1993

Dynamics of the hippocampal ensemble code for space.

Ensemble recordings of 73 to 148 rat hippocampal neurons were used to predict accurately the animals' movement through their environment, which confirms that the hippocampus transmits an ensemble code for location. In a novel space, the ensemble code was initially less robust but improved rapidly with exploration. During this period, the activity of many inhibitory cells was suppressed, which suggests that new spatial information creates conditions in the hippocampal circuitry that are conducive to the synaptic modification presumed to be involved in learning. Development of a new population code for a novel environment did not substantially alter the code for a familiar one, which suggests that the interference between the two spatial representations was very small. The parallel recording methods outlined here make possible the study of the dynamics of neuronal interactions during unique behavioral events.

Animals↗
PubMed1993

Behaviour and reproduction of the slender loris (Loris tardigradus) in captivity.

Observations were made on the behaviour of a group of slender lorises (Loris tardigardus) maintained in the Adelaide Zoo. Descriptions of their individual behaviour, social interactions, reproductive biology and development of young are given. The slender loris displays a more complex social life-style than has previously been reported, with huddling, marking activities and the behavioural complex of stretching/wrestling/allogrooming occurring daily. Evidence of the formation of a female coalition is described for the first time for this species. The low reproductive success of the group may have been attributable to the mixing of two Sri Lanka subspecies. Matings between L. tardigradus grandis and L. tardigradus tardigradus produced one sibling that reached maturity but did not breed.

Animals↗
PubMed1987

Conduct disordered adolescents from a community sample.

This study reports on a group of adolescents with conduct disorder in a community sample. Utilizing structured interviews for the adolescents and their parents, and strict requirements for caseness, conduct disorder was found to be the most common psychiatric problem (along with anxiety disorders). Various instruments were used. The findings, including approaches to conflict resolution in adolescents and their parents, are discussed.

Adolescent↗
PubMed2003

Relationship between craving and personality in treatment-seeking women with substance-related disorders.

BACKGROUND: Individual differences may impact susceptibility to addiction. The impact of personality features on drug craving, however, has not been studied, particularly in women. METHODS: Ninety-five treatment-seeking women with substance dependence, abstinent for at least 5 and no more than 21 days, were investigated regarding the correlation between personality factors and craving. Personality was assessed using the Temperament and Character Inventory (TCI), the NEO Personality Inventory Revised (NEO-PI-R), and the Barratt Impulsiveness Scale version 11 (BIS-11). Cravings were assessed through the Pennsylvania Craving Scale (PCS), and the Craving Questionnaire (CQ). Anxiety and depressive symptomatology were also recorded. RESULTS: Craving scores were positively correlated with depression and negatively correlated with number of days abstinent from substance use. Also, craving scores were positively associated with the novelty-seeking factor from the TCI and the total score on the BIS-11, and negatively associated with the conscientiousness and agreeableness facets of the NEO-PI-R. CONCLUSION: Findings suggest that personality features, particularly impulsiveness, can be important predictors of craving in women, which has important implications for treatment planning.

Behavior, Addictive↗
PubMed2003

The influence of social rank in the angelfish, Pterophyllum scalare, on locomotor and feeding activities in a novel environment.

To investigate differences in behaviour associated with social rank and environmental conditions, a comparison was made between swimming and feeding activities of dominant and subordinate angelfish, housed in groups of six, with those of angelfish housed singly in identical laboratory aquaria. Subordinate individuals were less active, less ready to feed and consumed less food items than dominants, but their feeding and activity levels were still greater than those displayed by isolated fish used as controls. When fish from each of the above categories were transferred to a novel, identical tank to be tested individually for a 6-day period, little change was observed in previously isolated fish. In contrast, the previous social experience had a marked influence on the behaviour of the other individuals, the effects being related to the social status. The strongest initial response to the new environment was shown by subordinate individuals, with a significant increase in swimming and a significant decrease in feeding compared to the group situation. Subordinates were significantly more active than dominants, who in turn moved more than previously isolated fish. Dominants and subordinates were now similarly reluctant to feed, and their food consumption was less than that of previously isolated fish. With time in the novel environment a significant reduction of swimming activity and a recovery of feeding measures were detected, but levels were still depressed in relation to the group condition, and lower in subordinates than in dominants, indicating the long-lasting effects of the previous social interactions. The results have clear implications for laboratory studies using groups of fish in which social hierarchies may be established prior to individuals being tested singly in a novel environment.

Animals↗