Developmental psychobiology最新文献

Previous research has sought to understand the mechanisms by which early life adversity disrupts later behavioral function. Yet less has been done to investigate the effects of positive experiences such as environmental enrichment. Here, we examined the effects of brief (2 weeks) or extended (8 weeks) environmental enrichment on discrimination, fear inhibition, and fear extinction during adolescence or adulthood. Two conditions of enrichment were used: a “Hut” group received a polycarbonate Hut in the home cage throughout the duration of the experiment, while a “Variable” group received a polycarbonate Hut, as well as a series of rotating enrichment features. Our data show that in females, brief Variable enrichment increased the rate of learning about cues that explicitly indicate safety during adolescence while disrupting this type of learning in adults. In males, enrichment did not influence learning about safety cues. Conversely, in males, brief Variable enrichment initially improved extinction, but extended enrichment (Variable or Hut) was necessary to see sustained improvements across extinction. This pattern was apparent for both adolescents and adults. In females, Variable enrichment did not affect extinction, while Hut enrichment increased freezing for all mice initially and adolescents as extinction continued. This work has the potential to inform treatments and interventions for fear-related disorders, such as anxiety and post-traumatic stress disorder, tailored for both specific developmental ages and sex.

Event-related potential (ERP) measures of reward- and error-related brain activity have been used to elucidate neural mechanisms contributing to the development of psychopathology. Adolescence is a critical developmental period that is associated with changes in ERP reward- and error-related brain activity. However, there is a paucity of within-subject research examining whether the reliability of ERP measures is the same or changes across adolescence. Moreover, it is unclear whether the time-frequency representation of reward- and error-related brain activity demonstrates similar psychometric properties. The present study examined the psychometric properties of reward- and error-related brain activity in five hundred and fifty 13.5- to 15.5-year-old (M = 14.4, SD = 0.63) girls. Participants completed the doors and flanker tasks while electroencephalography (EEG) was recorded at two assessments: baseline and 3 years later. Reward- and error-related brain activity were quantified using the time-domain reward positivity (RewP) and error-related negativity (ERN), respectively, as well as time-frequency delta and theta activity. Results indicated that all measures demonstrated adequate split-half reliability at each assessment and 3-year test–retest reliability across assessments. The present study indicates that the psychometric properties of time-domain and time-frequency reward- and error-related brain activity are largely consistent across adolescence, supporting their potential use as individual differences measures of risk for psychopathology.

This study employed latent change score models to examine the co-changes and mutual influences of fearful temperament, task switching, and maternal intrusiveness in early childhood. Participants included 335 children (171 boys, 164 girls; M_age = 3.09 years at baseline; 77.3% White, 14.0% Black, 8.4% multiracial, 0.3% Asian, 7.8% Hispanic) and their mothers. Higher levels of maternal intrusiveness at 36 months predicted a smaller increase in children's task switching between 36 and 48 months. Higher levels of task switching at 36 months predicted a larger decrease in fearful temperament. The changes between task switching and fearful temperament co-occurred; as the degree of task switching increased, fearful temperament decreased, or vice versa. Family-oriented interventions that reduce maternal intrusiveness may facilitate children's improvements in task switching, which is closely associated with the development of a fearful temperament.

Early disruption of filial attachment appears to sensitize underlying threat-related processes to produce vulnerability for developing depression when encountering stressors later in life. Evidence indicates neuroinflammatory signaling mediates this effect, though exact mechanisms are poorly understood. In a guinea pig model, early periods of isolation from the mother produce depressive-like behavior and fever, which sensitize with repeated isolation. Because cyclooxygenase inhibitors reduce these effects, the sensitization appears to involve prostaglandins such as PGE-2. We asked if isolation increased central sensitivity to PGE-2, which could underlie the sensitization process. Experiment 1 established that intraventricular (ICV) infusion of 1 or 3 µg of PGE-2 increased depressive-like behavior in pups. The 3 µg dose also produced an initial suppression and then a rise in core temperature. In Experiment 2, repeated isolation of pups sensitized depressive-like behavior. Days later (early adolescence), 1 µg of ICV-PGE-2 increased depressive-like behavior in previously isolated guinea pigs, but not in non-previously isolated controls. Core temperature was unaffected. Thus, early isolation from the mother increased sensitivity of depressive-like behavior, but not fever, to PGE-2. Results suggest that increased sensitivity to PGE-2 could play a role in the enhanced vulnerability to depression in adolescents previously exposed to early attachment disruption.

In male hamsters, puberty is associated with increased serotonin innervation and unusual responses to fluoxetine, such as enhanced play-fighting activity against intruders but also an acceleration of its maturation from attacks focused on the face (frontal attacks) to the lower belly and rump, suggesting a role for serotonin (5-HT). We tested the role of 5-HT_1A and 5-HT₃ receptor subtypes on play-fighting behavior observed during resident intruder tests through peripheral treatment with receptor agonists and antagonists. Contrary to observations in adult hamsters, we did not observe any overarching effects of treatment on measures of play-fighting activity, nor its maturation from frontal attacks. However, secondary analyses highlighted variability within the datasets. A subgroup of animals presented inhibited play-fighting activity in response to treatment with DPAT, a 5-HT_1A receptor agonist, but these animals also showed enhanced locomotor activity and reduced interest in engaging their opponents. In addition, early juvenile agonistic behavior was predictive of responsiveness to other treatments. The 5-HT_1A receptor antagonist, WAY, caused a reduction in play-fighting activity in high attackers and an increase in low attackers. Though high attackers under pretest conditions were equally inhibited by CBG, a 5-HT₃ receptor agonist, they performed a higher proportion of frontal attacks. Finally, the density of 5-HT_1A and 5-HT₃ receptor immunoreactivity was compared among subjects sampled at postnatal Day 35 (early puberty) or postnatal Day 70 (adulthood) within areas mediating the control of social behavior in adults. Adult males showed a higher density of immunolabeling for 5-HT_1A receptors in the anterior hypothalamus and medial amygdala, as well as 5-HT₃ receptors in the lateral septum. The data suggest that the development of 5-HT receptor expression participates in the control of play-fighting activity and its maturation during puberty in male hamsters.

The experience of maltreatment in childhood is associated with poorer developmental and health outcomes. This may be explained by the capacity for maltreatment to dysregulate stress-responsive neurophysiological systems, including the hypothalamic–pituitary–adrenal (HPA) axis. This study presents the results of the first meta-analysis that examines the association between maltreatment and resting HPA-axis activity in children and the role of “third variables” in accounting for observed heterogeneity in this association. Analyses of 18 studies, including N = 2216 children, indicated that although there was no difference in resting HPA-axis activity between children who had been maltreated and those who had not (standardized mean difference [SMD] = 0.04), there was substantial heterogeneity in the association between maltreatment and HPA-axis activity across studies (I² = 58.60%, p = 0.001). Further analyses revealed that the association between maltreatment and resting HPA-axis activity was contingent upon the source of information regarding maltreatment (B = 0.33, p = 0.002) and the degree to which maltreated and comparison groups differed in their socioeconomic status (B = 0.39, p = 0.037).