ABSTRACT
Compared to childhood and adulthood, adolescence is a time of greater risk-taking behavior, potentially resulting in serious consequences. Theories of adolescent brain development highlight the imbalance between neural circuitry for reward vs. regulation. Although this imbalance may make adolescents more vulnerable to impaired decision-making in the context of heightened arousal, not all adolescents exhibit problematic risk behavior, suggesting other factors are involved. Relatedly, parent-adolescent conflict increases in mid-adolescence, and is linked to negative outcomes like substance use related risk-taking. However, the mechanism by which parent-adolescent conflict and risk-taking are linked is still unknown. Therefore, we investigated this association using a multi-method experimental design. Parent-adolescent dyads were randomly assigned to complete a discussion task together on the topic of either the adolescent's dream vacation or an adolescent-identified conflict topic. During the task, adolescent peripheral psychophysiology was measured for later calculation of heart rate variability (HRV), an index of self-regulation. Immediately after the discussion task, adolescents completed a performance-based measure of risk-taking propensity that indexes real-world risk behaviors. We hypothesized that parent-adolescent conflict would predict greater adolescent risk-taking propensity, and that increased behavioral arousal in the context of conflict, coupled with impaired self-regulation, would explain this link. Results indicated no direct effect of parent-adolescent conflict on adolescent risk-taking propensity. However, there was a significant conditional indirect effect: lower HRV, indexing worse regulatory ability, mediated the relation between conflict and risk-taking propensity but only for adolescents exhibiting behavioral arousal during the discussion task. We discuss implications for understanding adolescent risk-taking behavior.
ABSTRACT
Parent-adolescent conflict poses risk for youth maladjustment. One potential mechanism of this risk is that stress in the form of increased arousal during conflict interactions results in adolescents' impaired decision-making. However, eliciting consistent adolescent stress responses within laboratory-based tasks of parent-adolescent conflict (i.e., conflict discussion tasks) is hindered by task design. This limitation may stem from how conflict topics are assessed and selected for discussion. Within a sample of 47 adolescents (ages 14-17) and parents, we investigated whether a modified version of a conflict discussion task could elicit physiological (i.e., arousal) and behavioral (i.e., hostility) displays of adolescents' conflict-related stress responses. We assessed parent-adolescent conflict via structured interview to identify topics for dyads to discuss during the task. We randomly assigned dyads to complete a 5-minute task to discuss either a putatively benign topic (i.e., control condition) or a conflict topic while undergoing direct assessments of continuous arousal. Trained raters coded dyad members' hostile behavior during the task. Adolescents in the conflict condition exhibited significantly greater levels of arousal than adolescents in the control condition. We observed an interaction between discussion condition and baseline conflict. Specifically, higher baseline conflict predicted greater hostile behavior for adolescents in the conflict condition, yet we observed the inverse relation for adolescents in the control condition. Our modified laboratory discussion task successfully elicited both physiological and behavioral displays of adolescent conflict-related stress. These findings have important implications for leveraging experimental paradigms to understand causal links between parent-adolescent conflict and adolescent psychopathology, and their underlying mechanisms.
ABSTRACT
Interval timing refers to the ability to perceive, estimate and discriminate durations in the range of seconds to minutes. Very little is currently known about the ontogeny of interval timing throughout development. On the other hand, even though the neural circuit sustaining interval timing is a matter of debate, the striatum has been suggested to be an important component of the system and its maturation occurs around the third post-natal (PN) week in rats. The global aim of the present study was to investigate interval timing abilities at an age for which striatum is not yet mature. We used odor fear conditioning, as it can be applied to very young animals. In odor fear conditioning, an odor is presented to the animal and a mild footshock is delivered after a fixed interval. Adult rats have been shown to learn the temporal relationships between the odor and the shock after a few associations. The first aim of the present study was to assess the activity of the striatum during odor fear conditioning using 2-Deoxyglucose autoradiography during development in rats. The data showed that although fear learning was displayed at all tested ages, activation of the striatum was observed in adults but not in juvenile animals. Next, we assessed the presence of evidence of interval timing in ages before and after the inclusion of the striatum into the fear conditioning circuit. We used an experimental setup allowing the simultaneous recording of freezing and respiration that have been demonstrated to be sensitive to interval timing in adult rats. This enabled the detection of duration-related temporal patterns for freezing and/or respiration curves in infants as young as 12 days PN during odor fear conditioning. This suggests that infants are able to encode time durations as well as and as quickly as adults while their striatum is not yet functional. Alternative networks possibly sustaining interval timing in infant rats are discussed.