Human cortical thickness and surface area are genetically independent, emerge through different neurobiological events during development, and are sensitive to different clinical conditions. However, the relationship between changes in the two over time is unknown. Additionally, longitudinal studies have almost invariably been restricted to older adults, precluding the delineation of adult life span trajectories of change in cortical structure. In this longitudinal study, we investigated changes in cortical thickness, surface area, and volume after an average interval of 3.6 years in 207 well screened healthy adults aged 23-87 years. We hypothesized that the relationships among metrics are dynamic across the life span, that the primary contributor to cortical volume reductions in aging is cortical thinning, and that magnitude of change varies with age and region. Changes over time were seen in cortical area (mean annual percentage change [APC], Ϫ0.19), thickness (APC, Ϫ0.35), and volume (APC, Ϫ0.51) in most regions. Volume changes were primarily explained by changes in thickness rather than area. A negative relationship between change in thickness and surface area was found across several regions, where more thinning was associated with less decrease in area, and vice versa. Accelerating changes with increasing age was seen in temporal and occipital cortices. In contrast, decelerating changes were seen in prefrontal and anterior cingulate cortices. In conclusion, a dynamic relationship between cortical thickness and surface area changes exists throughout the adult life span. The mixture of accelerating and decelerating changes further demonstrates the importance of studying these metrics across the entire adult life span.

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Basic perspective taking and mentalizing abilities develop in childhood, but recent studies indicate that the use of social perspective taking to guide decisions and actions has a prolonged development that continues throughout adolescence. Here, we aimed to replicate this research and investigate the hypotheses that individual differences in social perspective taking in adolescence are associated with real-life prosocial and antisocial behavior and differences in brain structure. We used an experimental approach and a large cross-sectional sample (n = 293) of participants aged 7–26 years old to assess age-related improvement in social perspective taking usage during performance of a version of the director task. In subsamples, we then tested how individual differences in social perspective taking were related to self-reported prosocial behavior and peer relationship problems on the Strengths and Difficulties Questionnaire (n = 184) and to MRI measures of regional cortical thickness and surface area (n = 226). The pattern of results in the director task replicated previous findings by demonstrating continued improvement in use of social perspective taking across adolescence. The study also showed that better social perspective taking usage is associated with more self-reported prosocial behavior, as well as to thinner cerebral cortex in regions in the left hemisphere encompassing parts of the caudal middle frontal and precentral gyri and lateral parietal regions. These associations were observed independently of age and might partly reflect individual developmental variability. The relevance of cortical development was additionally supported by indirect effects of age on social perspective taking usage via cortical thickness.

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Detecting errors and adjusting behaviour appropriately are fundamental cognitive abilities that are known to improve through adolescence. The underlying mechanisms of this development, however, are still poorly understood. To address this knowledge gap, we performed a thorough investigation of error processing in a Flanker task in a cross-sectional sample of participants 8 to 19 years of age (n = 98). We examined age-differences in event related potentials known to be associated with error processing, namely the error-related negativity (ERN) and the error positivity (Pe), as well as their relationships with task performance, post-error adjustments and regional cingulate cortex thickness and surface area. We found that ERN amplitude increased with age, while Pe amplitude remained constant. A more negative ERN was associated with higher task accuracy and faster reaction times, while a more positive Pe was associated with higher accuracy, independently of age. When estimating post-error adjustments from trials following both incongruent and congruent trials, post-error slowing and post-error improvement in accuracy both increased with age, but this was only found for posterror slowing when only analysing trials following incongruent trials. There were no age-independent associations between either ERN or Pe amplitude and cingulate cortex thickness or area measures.