Influence of Emotion on Cognitive Control from Adolescence to Adulthood

Adolescence is a period of development with high incidence of affective disorders representing poor cognitive control over affect, but little is known about how adolescent emotional systems compare to those of adults and how emotion influences still-maturing cognitive control systems. The ability to inhibit a response, which is crucial for cognitive control of behavior, continues to improve through adolescence. Though the core cognitive processes for inhibitory control are available in adolescence, the ability to utilize them in a reliable manner continues to mature, making adolescents susceptible to making errors. This study aimed to explore the vulnerabilities of the adolescent inhibitory control system to emotion by manipulating autonomic arousal. Adolescents (age 15-16) and adults (age 24-29) performed an oculomotor inhibitory control task as they heard sequences of temporally unpredictable tones (increased arousal condition) and temporally predictable tones (lower arousal, control condition) while autonomic arousal was assessed via pupillometry. Results indicated that adolescents have higher levels of arousal compared to adults, but less awareness of their arousal levels. Secondly, adolescents' inhibitory control was comparable to adults' even under arousal conditions but they showed greater effects of arousal reflected in optimal performance with higher levels of arousal. Thirdly, in adolescents but not adults, individuals who scored higher on measures of dysregulation showed greater sensitivity of inhibitory control to arousal. Together, these results indicate that emotional and inhibitory control processes are more susceptible to external stressors in adolescence than in adulthood. This may underlie known limitations during this period in higher level regulation of behavior, particularly in the face of stressors

Characterizing Developmental Growth and Individual Differences in Brain Systems Supporting Inhibitory Control: A Longitudinal fMRI Study

Inhibitory control, the ability to voluntarily suppress responses to task-irrelevant stimuli, enables goal-directed behaviors and continues to develop through adolescence. Neuroimaging studies indicate that developmental improvements in inhibitory performance are supported by the maturation of brain systems, but these studies have not used longitudinal designs and continuous metrics of age to characterize the process of growth or individual differences in trajectories. This study used longitudinal fMRI data from over 312 visits from 129 participants aged 8 to 28 years to characterize growth curves of brain function. Mean growth curves revealed developmental increases in activity within an error monitoring region, the dorsal anterior cingulate cortex (dACC). DACC activity was uniquely associated with task performance, suggesting that late-maturing dACC activity may be a primary process underlying the maturation of inhibitory control. Activity in the right dorsolateral prefrontal cortex (dlPFC) declined from childhood to adolescence, and may function as a scaffold to support immature networks. Growth curves across remaining areas of the inhibitory control circuitry did not show developmental changes, suggesting that the foundational inhibitory control system is available early in development. Investigating individual differences in trajectories revealed patterns of variability segregated according to function. Error monitoring evidenced the least variability, and executive control regions showed parallel trajectories, indicating a preservation of rank-order stability over development. Some motor response control regions showed a decline in variability with age,v indicating individuals follow different paths to the same end point of maturity. Sex predicted slope variability in a set of motor response control regions and an executive control region, with females but not males showing developmental declines in reactivity. Taken together, these findings extend prior cross-sectional studies to indicate that primary to the development of inhibitory control is enhanced error monitoring and less reliance on supportive dlPFC control. Further, results highlight important variability in developmental pathways, including notable sex differences

Functionally different PIN proteins control auxin flux during bulbil development in Agave tequilana

In Agave tequilana, reproductive failure or inadequate flower development stimulates the formation of vegetative bulbils at the bracteoles, ensuring survival in a hostile environment. Little is known about the signals that trigger this probably unique phenomenon in agave species. Here we report that auxin plays a central role in bulbil development and show that the localization of PIN1-related proteins is consistent with altered auxin transport during this process. Analysis of agave transcriptome data led to the identification of the A. tequilana orthologue of PIN1 (denoted AtqPIN1) and a second closely related gene from a distinct clade reported as ‘Sister of PIN1’ (denoted AtqSoPIN1). Quantitative real-time reverse transcription–PCR (RT-qPCR) analysis showed different patterns of expression for each gene during bulbil formation, and heterologous expression of the A. tequilana PIN1 and SoPIN1 genes in Arabidopsis thaliana confirmed functional differences between these genes. Although no free auxin was detected in induced pedicel samples, changes in the levels of auxin precursors were observed. Taken as a whole, the data support the model that AtqPIN1 and AtqSoPIN1 have co-ordinated but distinct functions in relation to auxin transport during the initial stages of bulbil formation

Time Spent with Parents Predicts Change in Depressive Symptoms in Adolescents with Major Depressive Disorder

Research with community samples suggests that non-affective features of families, such as the amount of time parents and adolescents spend together, affect depressive symptoms in adolescents. It is possible, however, that spending time with parents not only protects against the onset of depressive symptoms, but also reduces symptoms in adolescents who are already depressed. The current study was designed to test this formulation while also examining whether affective dimensions of family functioning – specifically parental warmth – accounted for or moderated observed associations. Finally, we tested the reverse direction of the associations, examining whether greater severity of depression in adolescents results in parents spending less time with them. Forty-one adolescents (ages 14 to 17 years) who met criteria for a current major depressive episode participated in the present study with one parent. Once each month for six time points, dyads completed reports of depressive symptoms and the amount of time parents and adolescents spent with each other. Participants also completed measures of parental warmth. Results of lagged multilevel modeling indicated that spending more time with a parent predicted fewer depressive symptoms in adolescents at the following assessment relative to their mean; in contrast, greater severity of depressive symptoms did not predict spending less time with a parent at the following assessment. In contrast, parental warmth did not account for or moderate the association between time together and depressive symptoms. These results suggest that non-affective dimensions of family life, specifically spending more time with parents, have beneficial effects on depressive symptoms in adolescents diagnosed with depression

Time-varying effects of income on hippocampal volume trajectories in adolescent girls

Children from lower-SES families exhibit smaller hippocampal volume than do their higher-SES peers. Few studies, however, have compared hippocampal developmental trajectories as a function of SES. Thus, it is unclear whether initial rank-order stability is preserved, or whether volumes diverge/converge over the course of adolescence. In a sample of 101 girls ages 10–24 years, we examined the longitudinal association between family income and parental education, proxies for SES, and changes in hippocampal volume. Hippocampal volume was obtained using MRI; using mixed modeling, we examined the effects of income and education on hippocampal volume across age. As expected, changes in volume were non-linear across development. Further, trajectories diverged in mid-adolescence, with lower-income girls exhibiting reductions in hippocampal volume. Maximal income-related differences were observed at 18 years, and trajectories converged thereafter. This interaction remained significant when accounting for maternal hippocampal volume, suggesting a unique contribution of environment over potential heritable differences. In contrast, the association between parental education and offspring hippocampal volume appeared to be stable across adolescence, with higher levels of parental education predicting consistently larger hippocampal volume. These findings constitute preliminary evidence that girls from lower-income homes exhibit unique trajectories of hippocampal growth, with differences most evident in late adolescence. Keywords: Adolescence, Adversity, Environmental influences, Family factors, Socioeconomic statu

Early Life Stress, Frontoamygdala Connectivity, and Biological Aging in Adolescence: A Longitudinal Investigation.

Early life stress (ELS) may accelerate frontoamygdala development related to socioemotional processing, serving as a potential source of resilience. Whether this circuit is associated with other proposed measures of accelerated development is unknown. In a sample of young adolescents, we examined the relations among ELS, frontoamygdala circuitry during viewing of emotional faces, cellular aging as measured by telomere shortening, and pubertal tempo. We found that greater cumulative severity of ELS was associated with stronger negative coupling between bilateral centromedial amygdala and the ventromedial prefrontal cortex, a pattern that may reflect more mature connectivity. More negative frontoamygdala coupling (for distinct amygdala subdivisions) was associated with slower telomere shortening and pubertal tempo over 2 years. These potentially protective associations of negative frontoamygdala connectivity were most pronounced in adolescents who had been exposed to higher ELS. Our findings provide support for the formulation that ELS accelerates maturation of frontoamygdala connectivity and provide novel evidence that this neural circuitry confers protection against accelerated biological aging, particularly for adolescents who have experienced higher ELS. Although negative frontoamygdala connectivity may be an adaptation to ELS, frontoamygdala connectivity, cellular aging, and pubertal tempo do not appear to be measures of the same developmental process

Target trial emulation: Do antimicrobials or gastrointestinal nutraceuticals prescribed at first presentation for acute diarrhoea cause a better clinical outcome in dogs under primary veterinary care in the UK?

Target trial emulation applies design principles from randomised controlled trials to the analysis of observational data for causal inference and is increasingly used within human epidemiology. Veterinary electronic clinical records represent a potentially valuable source of information to estimate real-world causal effects for companion animal species. This study employed the target trial framework to evaluate the usefulness on veterinary observational data. Acute diarrhoea in dogs was used as a clinical exemplar. Inclusion required dogs aged ≥ 3 months and < 10 years, presenting for veterinary primary care with acute diarrhoea during 2019. Treatment strategies were: 1. antimicrobial prescription compared to no antimicrobial prescription and 2. gastrointestinal nutraceutical prescription compared to no gastrointestinal nutraceutical prescription. The primary outcome was clinical resolution (defined as no revisit with ongoing diarrhoea within 30 days from the date of first presentation). Informed from a directed acyclic graph, data on the following covariates were collected: age, breed, bodyweight, insurance status, comorbidities, vomiting, reduced appetite, haematochezia, pyrexia, duration, additional treatment prescription and veterinary group. Inverse probability of treatment weighting was used to balance covariates between the treatment groups for each of the two target trials. The risk difference (RD) of 0.4% (95% CI -4.5% to 5.3%) was non-significant for clinical resolution in dogs treated with antimicrobials compared with dogs not treated with antimicrobials. The risk difference (RD) of 0.3% (95% CI -4.5% to 5.0%) was non-significant for clinical resolution in dogs treated with gastrointestinal nutraceuticals compared with dogs not treated with gastrointestinal nutraceuticals. This study successfully applied the target trial framework to veterinary observational data. The findings show that antimicrobial or gastrointestinal prescription at first presentation of acute diarrhoea in dogs causes no difference in clinical resolution. The findings support the recommendation for veterinary professionals to limit antimicrobial use for acute diarrhoea in dogs