Pubertal status associations with reward and threat sensitivities and subcortical brain volumes during adolescence

Adolescence is characterized by complex developmental processes that impact behavior, biology, and social functioning. Two such adolescence-specific processes are puberty and increases in reward sensitivity. Relations between these processes are poorly understood. The present study focused on examining unique effects of puberty, age, and sex on reward and threat sensitivities and volumes of subcortical brain structures relevant for reward/threat processing in a healthy sample of 9–18 year-olds. Unlike age, pubertal status had a significant unique positive relationship with reward sensitivity. In addition, there was a trend for adolescent females to exhibit higher threat sensitivity with more advanced pubertal development and higher reward and threat sensitivity with older age. Similarly, there were significant puberty by sex interaction effects on striatal volumes, i.e., left nucleus accumbens and right pallidum. The present pattern of results suggests that pubertal development, independent of chronological age, is uniquely associated with reward hypersensitivity and with structural differences in striatal regions implicated in reward processing.     

Sleep EEG changes during adolescence: An index of a fundamental brain reorganization

Delta (1–4 Hz) EEG power in non-rapid eye movement (NREM) sleep declines massively during adolescence. This observation stimulated the hypothesis that during adolescence the human brain undergoes an extensive reorganization driven by synaptic elimination. The parallel declines in synaptic density, delta wave amplitude and cortical metabolic rate during adolescence further support this model. These late brain changes probably represent the final ontogenetic manifestation of nature’s strategy for constructing nervous systems: an initial overproduction of neural elements followed by elimination. Errors in adolescent brain reorganization may cause mental illness; this could explain the typical age of onset of schizophrenia. Longitudinal studies of sleep EEG are enhancing our knowledge of adolescent brain maturation. Our longitudinal study of sleep EEG changes in adolescence showed that delta power, which may reflect frontal cortex maturation, begins its decline between ages 11 and 12 years and falls by 65% by age 17 years. In contrast, NREM theta power begins its decline much earlier. Delta and theta EEG frequencies are important to sleep theory because they behave homeostatically. Surprisingly, these brain changes are unrelated to pubertal maturation but are strongly linked to age. In addition to these (and other) maturational EEG changes, sleep schedules in adolescence change in response to a complex interaction of circadian, social and other influences. Our data demonstrate that the daytime sleepiness that emerges in adolescence is related to the decline in NREM delta as well as to altered sleep schedules. These longitudinal sleep data provide guideposts for studying cognitive and behavioral correlates of adolescent brain reorganization.     

Affect regulation, brain development, and behavioral/emotional health in adolescence

This paper addresses the importance of affect regulation (AR) in relation to a broad range of behavioral and emotional health problems that emerge during adolescence. AR is defined as the adaptive modulation of emotional experience to serve a goal or purpose. This conceptualization of AR emphasizes the use of cognitive skills to guide, inhibit, or modify emotion and behavior, including the expression of emotional responses, in learned, strategic ways-skills that ultimately underpin adult levels of social maturity and the ability to show "responsible" behavior across a range of emotional situations. Neurobehavioral systems that subserve these AR skills include areas of the inferior and orbital prefrontal cortex (PFC), with rich interconnections to several limbic structures and other cortical areas, including the dorsolateral PFC. Adolescence represents an important developmental period in the functional maturation of adult AR skills; it is also a critical time in the development of clinical disorders of AR (eg, rates of depression increase dramatically and gender differences in depression emerge). Maturational changes in AR that occur during adolescence-particularly with respect to the role of emotions influencing responsible decision making-are also relevant to understanding key aspects of the developmental pathways of some behavioral health problems, such as alcohol use and nicotine dependence. A strong case is made for developmental research in affective neuroscience aimed at this important maturational period, particularly the kind of transdisciplinary research leading toward mechanistic understanding of the development of adolescent-onset disorders. Improving understanding in these areas could ultimately lead to the development of early interventions in targeted high-risk populations, and has enormous clinical and social policy relevance.     

Developmental change in speed of processing during childhood and adolescence

Throughout childhood and adolescence, there are consistent age differences in speed of processing. Here 72 published studies yielded 1,826 pairs of response times (RTs) in which each pair consisted of adults' mean RT for a condition and the corresponding mean RT for a younger group. The primary results were that (a) children's and adolescents' RTs increase linearly as a function of adult RTs in corresponding conditions and (b) the amount of increase becomes smaller with age in a manner that is well described by an exponential function. These results are consistent with the view that age differences in processing speed reflect some general (i.e., nontask specific) component that changes rapidly during childhood and more slowly during adolescence. Possible candidates for the general component are discussed.     

Mapping brain maturation and cognitive development during adolescence

Non-invasive mapping of brain structure and function with magnetic resonance imaging (MRI) has opened up unprecedented opportunities for studying the neural substrates underlying cognitive development. There is an emerging consensus of a continuous increase throughout adolescence in the volume of white matter, both global and local. There is less agreement on the meaning of asynchronous age-related decreases in the volume of grey matter in different cortical regions; these might equally represent loss ("pruning") or gain (intra-cortical myelination) of tissue. Functional MRI studies have so far focused mostly on executive functions, such as working memory and behavioural inhibition, with very few addressing questions regarding the maturation of social cognition. Future directions for research in this area are discussed in the context of processing biological motion and matching perceptions and actions.     

Age‐related changes in transient and oscillatory brain responses to auditory stimulation during early adolescence

Maturational changes in the capacity to process quickly the temporal envelope of sound have been linked to language abilities in typically developing individuals. As part of a longitudinal study of brain maturation and cognitive development during adolescence, we employed dense‐array EEG and spatiotemporal source analysis to characterize maturational changes in the timing of brain responses to temporal variations in sound. We found significant changes in the brain responses compared longitudinally at two time points in early adolescence, namely 10 years (65 subjects) and 11.5 years (60 of the 65 subjects), as well as large differences between adults, studied with the same protocol ( Poulsen, Picton & Paus, 2007 ), and the children at 10 and 11.5 years of age. The transient auditory evoked potential to tone onset showed decreases in the latency of vertex and T‐complex components, and a highly significant increase in the amplitude of the N1 wave with increasing age. The auditory steady state response to a 40‐Hz frequency‐modulated tone increased in amplitude with increasing age. The peak frequency of the envelope‐following response to sweeps of amplitude‐modulated white noise also increased significantly with increasing age. These results indicate persistent maturation of the cortical mechanisms for auditory processing from childhood into middle adulthood.     

Longitudinal study of striatal activation to reward and loss anticipation from mid-adolescence into late adolescence/early adulthood

Adolescent risk-taking behavior has been associated with age-related changes in striatal activation to incentives. Previous cross-sectional studies have shown both increased and decreased striatal activation to incentives for adolescents compared to adults. The monetary incentive delay (MID) task, designed to assess functional brain activation in anticipation of reward, has been used extensively to examine striatal activation in both adult and adolescent populations. The current study used this task with a longitudinal approach across mid-adolescence and late adolescence/early adulthood. Twenty-two participants (13 male) were studied using the MID task at two time-points, once in mid-adolescence (mean age = 16.11; SD = 1.44) and a second time in late adolescence/early adulthood (mean age = 20.14; SD = .67). Results revealed greater striatal activation with increased age in high- compared to low-incentive contexts (incentive magnitude), for gain as well as for loss trials (incentive valence). Results extend cross-sectional findings and show reduced striatal engagement in adolescence compared to adulthood during preparation for action in an incentive context.     

Developmental changes in the processing of hierarchical shapes continue into adolescence

The present study was designed to trace the normal development of local and global processing of hierarchical visual forms. We presented pairs of hierarchical shapes to children and adults and asked them to indicate whether the two shapes were the same or different at either the global or the local level. In Experiments 1 (6-year-olds, 10-year-olds, adults) and 2 (10-year-olds, 14-year-olds, adults), we presented stimuli centrally. All age groups responded faster on global trials than local trials (global precedence effect), but the bias was stronger in children and diminished to the adult level between 10 and 14 years of age. In Experiment 3 (10-year-olds, 14-year-olds, adults), we presented stimuli in the left or right visual field so that they were transmitted first to the contralateral hemisphere. All age groups responded faster on local trials when stimuli were presented in the right visual field (left hemisphere); reaction times on global trials were independent of visual field. The results of Experiment 3 suggest that by 10 years of age the hemispheres have adult-like specialization for the processing of hierarchical shapes, at least when attention is directed to the global versus local level. Nevertheless, their greater bias in Experiments 1 and 2 suggests that 10-year-olds are less able than adults to modulate attention to the output from local versus global channels-perhaps because they are less able to ignore distractors and perhaps because the cerebral hemispheres are less able to engage in parallel processing.     

急性疼痛与慢性疼痛对奖赏加工的影响及神经机制

疼痛和奖赏能够为个体提供不同的行为动机和主观价值体验,寻求奖赏和避免疼痛对于生存都很重要。疼痛可划分为急性疼痛和慢性疼痛,奖赏可区分为预期阶段的动机成分和体验阶段的享乐成分。奖赏对疼痛的抑制作用已经被广泛证实,但关于疼痛对奖赏的影响,目前的研究结果并不一致。因此需要进一步区分并探究急性疼痛与慢性疼痛对奖赏加工不同阶段的影响,分析两种疼痛对奖赏加工产生不一致影响的现象。这种现象出现的原因可能与急性疼痛向慢性疼痛转变过程中出现的奖赏加工能力缺陷有关。未来可以考虑从改善奖赏加工能力缺陷的角度进行检测和治疗,提前预防急性疼痛向慢性疼痛转变。     

Modulations of sensory-evoked brain potentials indicate changes in perceptual processing during visual-spatial priming.

Reaction time (RT) differences to visual stimuli as a function of expectancy have been attributed to changes in perceptual processing or entirely to shifts in decision and response criteria. To help distinguish between these competing interpretations, event-related brain potentials (ERPs) were recorded to lateralized flashes delivered to visual field locations precued by a central arrow (valid stimuli) or not precued (invalid stimuli). Validly cued stimuli in both simple and choice RT tasks elicited consistent amplitude enhancements of the early, sensory-evoked PI component of the ERP recorded at scalp sites overlying lateral prestriate visual cortex (90-130 ms poststimulus). In contrast, the subsequent N1 component (150-200 ms) was enhanced by validly cued stimuli in the choice RT task condition only. These electrophysiological findings support models proposing that the behavioral effects of precuing expected target locations are due, at least in part, to changes in sensory-perceptual processing. Furthermore, these data provide specific information regarding the neural mechanisms underlying such effects.     

Lateral asymmetry in phonological processing: relating behavioral measures to neuroimaged structures

Recent neuroimaging studies have revealed neuroanatomical centers of activation that appear to be linked specifically to phonological processes. Furthermore, there is evidence that these centers of activation are more likely to be bilaterally represented in women than in men. However, behavioral evidence of such hemispheric asymmetries or of related sex differences is somewhat inconsistent. Two experiments were carried out to determine whether behavioral correlates of the neuroimaging findings could be demonstrated. The first experiment employed a rhyme-matching task used in a recent neuroimaging study, in which two nonsense words were projected successively to the left or right sides of the visual field. The results indicated that the left hemisphere was superior for this task. An analysis of gender effects, however, revealed that the asymmetry was restricted to men. The second experiment employed a lateralized pseudohomophone detection task that was designed to determine whether the results of the first experiment could be confirmed in the context of a phonological task with a simpler structure. This experiment broadly supported the findings of the first experiment. The results support the specialization of the left hemisphere for phonological processing, and the existence of gender differences with respect to these processes.     

Changes in identification during adolescence: a personal construct theory approach

The Role Construct Repertory Grid was administered individually to groups of eight subjects representing the early, mid and late adolescence age ranges. The Mid-Adolescence Group showed significantly greater conceptual distances between ideal-self and actual-self than either of the other groups. Differences between the age groups on self-integration plots and a measure of self-isolation were also observed. Evidence was found of decreasing identification with parents as a function of age.     

Longitudinal changes in marital satisfaction during middle age in Taiwan

The current 8‐year panel study explored changes in marital satisfaction among 614 married middle‐aged persons with seventh‐grade children. It also examined how individual health (physical health and depressive moods) and role changes (parenting transitions and life stress) were related to trajectories of marital satisfaction and investigated the buffering effect of family cohesion on these associations. Growth curve analyses show an inverted‐U shape in marital satisfaction during middle age. This indicates that regardless of the gender or age of the respondents, marital satisfaction among middle‐aged adults increased when their children were in the 9^th and 12^th grade, and then declined when their children were in their sophomore year of college. Declining physical health and an increase in depressive moods were related to a drop in marital satisfaction. Stressful events in midlife had negative effects on marital satisfaction, and family cohesion served as a buffer to mitigate the adverse impact of life stress on marital satisfaction. Overall, these results highlight the role of adolescent children in understanding why marital satisfaction changes among middle‐aged parents and emphasize the importance of health and life stress in relation to midlife marital satisfaction. These findings are discussed with life course perspectives and Taiwanese cultural values in relation to familism and academic achievement among children.     

Longitudinal associations between impulsivity and lie-telling in childhood and adolescence

Lie-telling and impulsivity levels peak during late childhood to early adolescence and have been suggested to be related. Heightened impulsivity may lead adolescents to lie in favor of short-term benefits without consideration for the potential consequences of deception. The present study assessed longitudinal relations between self-reported impulsivity and lie-telling frequency. Participants from a large-scale longitudinal study (N = 1148; M_age = 11.55, SD = 1.69, 9–15 years at Time 1) reported on their impulsivity (Barratt Impulsiveness Scale) and their frequency of lie-telling to parents, to teachers, to friends, and about cheating across two time points 1 year apart. Cross-lagged path analysis revealed greater impulsivity was associated with more frequent lie-telling to parents, friends, and teachers, and about cheating over time. Our findings demonstrate the role of impulsivity in the development of lie-telling behaviors.

Research Highlights

• Impulsivity predicts lying across time in multiple contexts (to parents, friends, teachers, and about cheating).
• Previous research has demonstrated the role of top-down influences on lie-telling, but the current study suggests that bottom-up processes are also influential.

     

Longitudinal pathways between mental health difficulties and academic performance during middle childhood and early adolescence

There is a growing appreciation that child functioning in different domains, levels, or systems are interrelated over time. Here, we investigate links between internalizing symptoms, externalizing problems, and academic attainment during middle childhood and early adolescence, drawing on two large data sets (child: mean age 8.7 at enrolment, n = 5,878; adolescent: mean age 11.7, n = 6,388). Using a 2‐year cross‐lag design, we test three hypotheses – adjustment erosion, academic incompetence, and shared risk – while also examining the moderating influence of gender. Multilevel structural equation models provided consistent evidence of the deleterious effect of externalizing problems on later academic achievement in both cohorts, supporting the adjustment‐erosion hypothesis. Evidence supporting the academic‐incompetence hypothesis was restricted to the middle childhood cohort, revealing links between early academic failure and later internalizing symptoms. In both cohorts, inclusion of shared‐risk variables improved model fit and rendered some previously established cross‐lag pathways non‐significant. Implications of these findings are discussed, and study strengths and limitations noted.

Statement of contribution

What is already known on this subject?

• Longitudinal research and in particular developmental cascades literature make the case for weaker associations between internalizing symptoms and academic performance than between externalizing problems and academic performance.
• Findings vary in terms of the magnitude and inferred direction of effects. Inconsistencies may be explained by different age ranges, prevalence of small‐to‐modest sample sizes, and large time lags between measurement points.
• Gender differences remain underexamined.

What does this study add?

• The present study used cross‐lagged models to examine longitudinal associations in age groups (middle child and adolescence) in a large‐scale British sample.
• The large sample size not only allows for improvements on previous measurement models (e.g., allowing the analysis to account for nesting, and estimation of latent variables) but also allows for examination of gender differences.
• The findings clarify the role of shared‐risk factors in accounting for associations between internalizing, externalizing, and academic performance, by demonstrating that shared‐risk factors do not fully account for relationships between internalizing, externalizing, and academic achievement. Specifically, some pathways between mental health and academic attainment consistently remain, even after shared‐risk variables have been accounted for.
• Findings also present consistent support for the potential impact of behavioural problems on children's academic attainment.
• The negative relationship between low academic attainment and subsequent internalizing symptoms for younger children is also noteworthy.

     

Sex differences in the neural underpinnings of social and monetary incentive processing during adolescence

The brain’s reward system undergoes major changes during adolescence, and an increased reactivity to social and nonsocial incentives has been described as a typical feature during this transitional period. Little is known whether there are sex differences in the brain’s responsiveness to social or monetary incentives during adolescence. The aim of this event-related potential (ERP) study was to compare the neurophysiological underpinnings of monetary and social incentive processing in adolescent boys versus girls. During ERP recording, 38 adolescents (21 females, 17 males; 13–18 years) completed an incentive delay task comprising (a) a reward versus punishment condition and (b) social versus monetary incentives. The stimulus-preceding negativity (SPN) was recorded during anticipation of reward and punishment, and the feedback P3 (fP3) along with the feedback-related negativity (FRN) after reward/punishment delivery. During anticipation of social punishment, adolescent boys compared with girls exhibited a reduced SPN. After delivery, male adolescents exhibited higher fP3 amplitudes to monetary compared with social incentives, whereas fP3 amplitudes in girls were comparable across incentive types. Moreover, whereas in boys fP3 responses were higher in rewards than in punishment trials, no such difference was evident in girls. The results indicate that adolescent boys show a reduced neural responsivity in the prospect of social punishment. Moreover, the findings imply that, once the incentive is obtained, adolescent boys attribute a relatively enhanced motivational significance to monetary incentives and show a relative hyposensitivity to punishment. The findings might contribute to our understanding of sex-specific vulnerabilities to problem behaviors related to incentive processing during adolescence.     

Fluctuations in brain glucose concentration during behavioral testing: dissociations between brain areas and between brain and blood

Traditional beliefs about two aspects of glucose regulation in the brain have been challenged by recent findings. First, the absolute level of glucose in the brain's extracellular fluid appears to be lower than previously thought. Second, the level of glucose in brain extracellular fluid is less stable than previously believed. In vivo brain microdialysis was used, according to the method of zero net flux, to determine the basal concentration of glucose in the extracellular fluid of the striatum in awake, freely moving rats for comparison with recent hippocampal measurements. In addition, extracellular glucose levels in both the hippocampus and the striatum were measured before, during, and after behavioral testing in a hippocampus-dependent spontaneous alternation task. In the striatum, the resting extracellular glucose level was 0.71 mM, approximately 70% of the concentration measured previously in the hippocampus. Consistent with past findings, the hippocampal extracellular glucose level decreased by up to 30 +/- 4% during testing; no decrease, and in fact a small increase (9 +/- 3%), was seen in the striatum. Blood glucose measurements obtained during the same testing procedure and following administration of systemic glucose at a dose known to enhance memory in this task revealed a dissociation in glucose level fluctuations between the blood and both striatal and hippocampal extracellular fluid. These findings suggest, first, that glucose is compartmentalized within the brain and, second, that one mechanism by which administration of glucose enhances memory performance is via provision of increased glucose supply from the blood specifically to those brain areas involved in mediating that performance.     

Longitudinal links between career adaptability and academic achievement in adolescence

Contemporary youth spend increasingly longer time in the educational system, where their career pursuits become closely intertwined with their educational goals. As career development is a life-long process, adolescents start working on their careers long before they engage in actual work behaviors. Therefore, in order for school to adaptively prepare youth for their future work lives, career adaptability and academic achievement should be reciprocally and positively linked throughout adolescence. To date, more longitudinal proof for these relations is needed. To address this shortcoming, we investigated cross-lagged associations between these two constructs in a three-wave longitudinal study, testing the moderating role of adolescents' gender, school type, and age. Participants were 1151 adolescents (41.3% boys), who completed the same paper-and-pencil measure three times across an academic year. Results showed positive reciprocal associations between career concern and academic achievement (i.e., Grand Point Average). This indicates that adolescents with a strong future orientation, who were already invested in career planning activities tended to perform better in school and vice-versa, high academic achievement further strengthened adolescents' positive outlooks on their vocational future. We also detected positive unidirectional links from academic achievement to career control and career confidence across one academic year. Interestingly, we did not find significant longitudinal links between career curiosity and academic achievement. These patterns of longitudinal relations applied equally to boys and girls, to those attending university-preparatory and work-bound schools, and to early-to-middle and middle-to-late adolescents. Research and applied implications of these findings are detailed.     

Information content and reward processing in the human striatum during performance of a declarative memory task

Negative feedback can signal poor performance, but it also provides information that can help learners reach the goal of task mastery. The primary aim of this study was to test the hypothesis that the amount of information provided by negative feedback during a paired-associate learning task influences feedback-related processing in the caudate nucleus. To do this, we manipulated the number of response options: With two options, positive and negative feedback provide equal amounts of information, whereas with four options, positive feedback provides more information than does negative feedback. We found that positive and negative feedback activated the caudate similarly when there were two response options. With four options, the caudate’s response to negative feedback was reduced. A secondary goal was to investigate the link between brain-based measures of feedback-related processing and behavioral indices of learning. Analysis of the posttest measures showed that trials with positive feedback were associated with higher posttest confidence ratings. Additionally, when positive feedback was delivered, caudate activity was greater for trials with high than with low posttest confidence. This experiment demonstrated the context sensitivity of feedback processing and provided evidence that feedback processing in the striatum can contribute to the strengthening of the representations available within declarative memory.