Denial of Reward in the Neonate Shapes Sociability and Serotonergic Activity in the Adult Rat (original) (raw)
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Psychopharmacology, 2007
Rationale Serotonin is an important modulator of social behaviour. Individual differences in serotonergic signalling are considered to be a marker of personality that is stable throughout lifetime. While a large body of evidence indicates that central serotonin levels are inversely related to aggression and sexual behaviour in adult rats, the relationship between serotonin and social behaviour during peri-adolescence has hardly been explored. Objective To study the effect of acute and constitutive increases in serotonin neurotransmission on social behaviour in peri-adolescent rats. Materials and methods Social behaviour in peri-adolesent rats (28-35 days old) was studied after genetic ablation of the serotonin transporter, causing constitutively increased extra-neuronal serotonin levels, and after acute treatment with the serotonin reuptake inhibitor fluoxetine or the serotonin releasing agent 3,4-methylenedioxymethamphetamine (MDMA). A distinction was made between social play behaviour that mainly occurs during peri-adolescence, and non-playful social interactions that are abundant during the entire lifespan of rats.
Brain Research Bulletin, 2004
Continuous exposure of non-parturient rats to pups can induce maternal behavior similar in most aspects to that found in the postpartum rat. Surprisingly, young juvenile rats (20-24 days of age) only require 1-3 days of exposure to pups, while adults require 4-8 days before maternal behavior emerges. Dopamine (DA) and possibly serotonin (5-HT) may mediate the expression of adult maternal behavior. We hypothesize that postnatal changes in DA and 5-HT within the neural circuit that supports maternal behavior including the medial preoptic area (MPOA), medial and cortical amygdala (MCA), and nucleus accumbens (NAC), may underlie these differences in responsiveness across juveniles and adults. We measured DA, 5-HT, and their metabolites in postmortem samples of these regions in maternal and non-maternal juvenile and adult females. 11 12 13 14 15 16 17
Mild environmental intervention in mother-infant interactions reduces social play behavior in rats
Psychology & Neuroscience, 2013
During early life, animals are sensitive to environmental events that may lead to short-term and long-lasting changes in their neurobiology and behavior, which could be related to increased risk for psychopathology. Neonatal handling is an experimental intervention in the mother-infant relationship. Based on previous studies, it is known to decrease rat pups' preference for maternal cues. Handling also reduces social, sexual, and fear behavior in adult animals, which is related to underlying neuroendocrine alterations. One prominent feature of adolescence is the high frequency of social behaviors such as play that appear to be necessary for proper socioemotional development. The objective of the present study was to investigate the effect of repeatedly handling pups on social play behavior during the neonatal period in juvenile Wistar rats. We found that handling consistently decreased pouncing, wrestling, and chasing play behavior on postnatal days (PND) 25, 30, and 35 compared with non-handled juveniles. As expected, sex differences were also found. Consistent with previous studies in infant and adult rats, the neonatal handling procedure also reduced affiliative behaviors in juvenile animals. The precise mechanisms by which this early intervention leads to these alterations in offspring remain to be determined, but the cumulative effects of briefly disrupting the mother-infant relationship that caused the neonatal handling may be one possible explanation.
Early life stress induces submissive behavior in adult rats
Behavioural Brain Research, 2019
Maternal-deprivation of rodent pups is a relevant model of extreme early-life stress that can be relevant to the understanding of long-term effects of war, migration, parental loss and displacement. Although even mild stress during infancy affects brain development and behavior, the current study focused on the effects of six hour daily maternal-separation, a model that reflects the severe distress often experienced in those circumstances. This study emphasizes the effect of maternal separation on social behavior in the context of a variety of factors that measure cognitive and emotional behavior which were subject to principle component analysis. Sprague-Dawley pups were separated from the dam for 6 h each day during the first 3-weeks of life and underwent a battery of behavioral tests at 3-months of age. We found that rodents exposed to postnatal maternal deprivation displayed submissive behavior in residentintruder and dominant-submissive tests, as well as significantly more anxiety and anhedonia than control rats. The results of multivariate statistical analysis show that the dominant-submissive behavior correlates with depressive, anxiety and social behavior and can be predicted with an accuracy of 86.2%. The increased submissive behavior in male rats that had been subjected to severe postnatal stress suggests that exposure to stress during infancy and childhood could have long-term effects on social relationships. The mechanism of the longterm effects on depression, anxiety and submissive behavior requires further investigation.
Behavioral and neurobiological consequences of social subjugation during puberty in golden hamsters
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1998
In golden hamsters, offensive aggression is facilitated by vasopressin and inhibited by serotonin. We tested whether these neurotransmitter systems respond to modifications resulting from the stress of threat and attack (i.e., social subjugation) during puberty. Male golden hamsters were weaned at postnatal day 25 (P25), exposed daily to aggressive adults from P28 to P42, and tested for offensive aggression as young adults (P45). The results showed a context-dependent alteration in aggressive behavior. Subjugated animals were more likely to attack younger and weaker intruders than nonsubjugated controls. Conversely, subjugated animals were less likely to attack animals of similar size and age. After testing, the animals were killed, and their brains were collected to determine whether these behavioral changes are underlined by changes in the vasopressin and serotonin systems. Social subjugation resulted in a 50% decrease in vasopressin levels within the anterior hypothalamus, a site...
Neuroscience & Biobehavioral Reviews, 2003
Depression is a major public health concern, representing one of the most significant causes of disability and morbidity. Despite significant advances in the definition of specific cognitive, emotional and neural dysfunctions that are associated with depression, there has been frustratingly little progress in the elucidation of plausible aetiological and pathophysiological mechanisms. The complex, multi-system dysfunctions of depressive illness do not lend themselves to hypothesis-driven, systematic manipulation in patients. For this reason, there is a need to develop valid and reliable models of affective psychopathology in laboratory animals. In this paper, we review briefly some of our previous work demonstrating that a specific periodic neonatal maternal separation procedure leads to a robust constellation of behavioural changes in the adult rat that resemble core aspects of human depressive psychopathology. We also present data from a study of the adult effects of the same manipulation on electrical intracranial self-stimulation behaviour. These data further support the hypothesis that it is possible to model vulnerability to anhedonia in the adult rat by manipulation of early experience. q
Postnatal experiences influence the behavior in adult male and female Fischer and Lewis rats
International journal of developmental neuroscience : the official journal of the International Society for Developmental Neuroscience, 2010
The postnatal environment with the rat pups' dam as the most important regulator, plays a central role in determining developmental processes of the offspring. Early disturbances of the dam-pup-dyade, like separation from the dam for hours (maternal deprivation, MD), or a short period of separation, and exposure to novelty, like the handling stimulation (HA), might induce long-lasting changes within the individual. To further investigate the susceptibility to these postnatal manipulations with regard to both, sex and genetic background, we used male and female Fischer (F344) and Lewis (LEW) rats. F344 and LEW rats were daily subjected to either HA, MD, or were left undisturbed until weaning. The immediate effects of these manipulations were studied using the mother-pup-interaction-test on postnatal days 3-7. At the age of 4 months, animals were subjected to a behavioral test battery, determining activity, exploration, and anxiety-like behavioral parameters. Postnatal manipulatio...
Behavioural brain research, 2014
Early-life social adversity, such as child neglect and institutionalized rearing, is associated with later-life difficulties of inhibitory control that may reflect altered attribution of salience to external stimuli. Studies in rats demonstrate that early-life social deprivation results in enhanced responsiveness to reward stimuli and conditioned reward cues. This study examined whether these effects are related to fundamental changes in appetitive conditioning processes involving instrumental goal-directed and habitual responding for food reward. Rats were reared either by the mother (maternal rearing; MR) or in complete isolation from the mother and litter (artificial rearing; AR) and tested as adults in two appetitive conditioning tasks. AR and MR rats did not differ in the amount of goal-directed effort they exerted to obtain food reward on progressive ratio schedules of reinforcement. AR and MR rats also did not differ in the shift from goal-directed to habitual responding on a...