Cognitive Control in Adolescence: Neural Underpinnings and Relation to Self-Report Behaviors

Adolescence is commonly characterized by impulsivity, poor decision-making, and lack of foresight. However, the developmental neural underpinnings of these characteristics are not well established.To test the hypothesis that these adolescent behaviors are linked to under-developed proactive control mechanisms, the present study employed a hybrid block/event-related functional Magnetic Resonance Imaging (fMRI) Stroop paradigm combined with self-report questionnaires in a large sample of adolescents and adults, ranging in age from 14 to 25. Compared to adults, adolescents under-activated a set of brain regions implicated in proactive top-down control across task blocks comprised of difficult and easy trials. Moreover, the magnitude of lateral prefrontal activity in adolescents predicted self-report measures of impulse control, foresight, and resistance to peer pressure. Consistent with reactive compensatory mechanisms to reduced proactive control, older adolescents exhibited elevated transient activity in regions implicated in response-related interference resolution.Collectively, these results suggest that maturation of cognitive control may be partly mediated by earlier development of neural systems supporting reactive control and delayed development of systems supporting proactive control. Importantly, the development of these mechanisms is associated with cognitive control in real-life behaviors

Task Control Signals in Pediatric Tourette Syndrome Show Evidence of Immature and Anomalous Functional Activity

Tourette Syndrome (TS) is a pediatric movement disorder that may affect control signaling in the brain. Previous work has proposed a dual-networks architecture of control processing involving a task-maintenance network and an adaptive control network (Dosenbach et al., 2008). A prior resting-state functional connectivity MRI (rs-fcMRI) analysis in TS has revealed functional immaturity in both putative control networks, with “anomalous” correlations (i.e., correlations outside the typical developmental range) limited to the adaptive control network (Church et al., 2009). The present study used functional MRI (fMRI) to study brain activity related to adaptive control (by studying start-cues signals), and to task-maintenance (by studying signals sustained across a task set). Two hypotheses from the previous rs-fcMRI results were tested. First, adaptive control (i.e., start-cue) activity will be altered in TS, including activity inconsistent with typical development (“anomalous”). Second, group differences found in task-maintenance (i.e., sustained) activity will be consistent with functional immaturity in TS. We examined regions found through a direct comparison of adolescents with and without TS, as well as regions derived from a previous investigation that showed differences between unaffected children and adults. The TS group showed decreased start-cue signal magnitude in regions where start-cue activity is unchanged over typical development, consistent with anomalous adaptive control. The TS group also had higher magnitude sustained signals in frontal cortex regions that overlapped with regions showing differences over typical development, consistent with immature task-maintenance in TS. The results demonstrate task-related fMRI signal differences anticipated by the atypical functional connectivity found previously in adolescents with TS, strengthening the evidence for functional immaturity and anomalous signaling in control networks in adolescents with TS

At risk of being risky: The relationship between "brain age" under emotional states and risk preference.

Developmental differences regarding decision making are often reported in the absence of emotional stimuli and without context, failing to explain why some individuals are more likely to have a greater inclination toward risk. The current study (N=212; 10-25y) examined the influence of emotional context on underlying functional brain connectivity over development and its impact on risk preference. Using functional imaging data in a neutral brain-state we first identify the "brain age" of a given individual then validate it with an independent measure of cortical thickness. We then show, on average, that "brain age" across the group during the teen years has the propensity to look younger in emotional contexts. Further, we show this phenotype (i.e. a younger brain age in emotional contexts) relates to a group mean difference in risk perception - a pattern exemplified greatest in young-adults (ages 18-21). The results are suggestive of a specified functional brain phenotype that relates to being at "risk to be risky.

Cognitive control development in adolescence

Adolescence is a transitional period in which an increasing ability to coordinate basic cognitive control abilities is also particularly challenged by contextual factors in the environment. The aim of this dissertation was to examine the development of complex cognitive control in adolescence in relation to different socio-affective contexts at the behavioural and neural level. The dissertation presents three functional magnetic resonance imaging (fMRI) experiments. The first studies explored transient and sustained aspects of cognitive control, and how the context influences behaviour and brain activation during cognitive control tasks. Study 1 used a prospective memory task where the cues were more or less salient, affecting the need to proactively monitor the stimuli vs. react to more distinctive cues. Study 2 used a working memory task and manipulated the reward context, on a trial-by-trial or run-by-run basis. Study 3 used a relational reasoning task to investigate manipulation and integration of information and its sensitivity to the nature of this information, in particular whether making judgements in the social domain elicited specific brain activations compared to the non-social domain. All three studies were run in adolescent and adult participants, to allow the study of developmental changes in complex cognitive control at the behavioural and brain level. Study 1 found behavioural evidence for development of prospective memory in adolescence and neuroimaging evidence for sustained and transient activation of the frontoparietal network associated with monitoring costs for cue detection whilst being engaged in a different task. Study 2 found that in the context of sporadic rewards, both adolescents and adults combine a proactive and a reactive strategy to maximise performance. Reward had both sustained and transient effects on frontoparietal regions as well as subcortical regions involved in reward processing. Study 3 showed parallel recruitment of the social brain and the relational reasoning network during the relational integration of social information in adolescence and adulthood. Across the three studies, there was evidence for behavioural improvement with age, but no strong differences of haemodynamic brain changes between adolescence and adulthood

Convergent and divergent fMRI responses in children and adults to increasing language production demands

In adults, patterns of neural activation associated with perhaps the most basic language skill—overt object naming—are extensively modulated by the psycholinguistic and visual complexity of the stimuli. Do children's brains react similarly when confronted with increasing processing demands, or they solve this problem in a different way? Here we scanned 37 children aged 7–13 and 19 young adults who performed a well-normed picture-naming task with 3 levels of difficulty. While neural organization for naming was largely similar in childhood and adulthood, adults had greater activation in all naming conditions over inferior temporal gyri and superior temporal gyri/supramarginal gyri. Manipulating naming complexity affected adults and children quite differently: neural activation, especially over the dorsolateral prefrontal cortex, showed complexity-dependent increases in adults, but complexity-dependent decreases in children. These represent fundamentally different responses to the linguistic and conceptual challenges of a simple naming task that makes no demands on literacy or metalinguistics. We discuss how these neural differences might result from different cognitive strategies used by adults and children during lexical retrieval/production as well as developmental changes in brain structure and functional connectivity

Focal Spot, Fall/Winter 2003/2004

https://digitalcommons.wustl.edu/focal_spot_archives/1095/thumbnail.jp

The Development of Flexible Behavior: Age Differences and Training-Related Changes in Activation, Connectivity, and Neural Representations During Task Switching

The ability to flexibly adapt behavior in the light of changing contextual demands is crucial for successful goal pursuit. With age, children become increasingly able to flexibly switch between tasks but show poorer switching performance even in late childhood. Given the crucial role of cognitive flexibility in daily life, such as the ability to shift to a new strategy to solve a problem when the previous one did not work, studies have aimed to improve cognitive flexibility with training in children. A key question for the effectiveness of these interventions is understanding why children show lower cognitive flexibility than adults. In this dissertation, I shed new light on this question, by investigating 8–11-year-old children using behavioral measures in combination with measures of univariate activation, multivariate decoding, and task-related connectivity based on data from functional magnetic resonance imaging (fMRI). In Papers 1 & 2, I first addressed the question of which neural processes support the development of cognitive flexibility. In Paper 3, I examined how these neural processes change with training. I have prefaced the three papers with a synopsis in which I outline the theoretical framework of the dissertation and summarize the current empirical findings. Finally, I summarize the results of the empirical part of this dissertation and discuss their contribution to our understanding of the development of cognitive flexibility. Flexibly switching between tasks comes at a cost, evident in decreased accuracy and increased response times. Specifically, compared to performing single tasks in isolation, task switching poses greater demands on maintaining and managing multiple task sets, thus eliciting so-called mixing costs. Additionally, a switch to a different task compared to a repetition of the same one requires the inhibition of the previously relevant task set and updating the newly relevant one, resulting in so-called switch costs. Previous research has demonstrated that mixing and switch costs show different patterns of age differences with switch costs approaching adult levels earlier. The present dissertation builds on these findings to examine the neurocognitive processes contributing to the presumably protracted development of mixing costs. In Paper 1, comparing children (8–11 years) and adults (20–30 years), I examined how neural processes supporting sustained and transient control processes support age-related decreases in mixing and switch costs, respectively. I showed that while evident for both, age differences were greater for sustained activation and mixing costs than for transient activation and switch costs. Additionally, the results of Paper 1 outline a potential alternative mechanism via which children can address increased sustained control demands: children that showed a less adult-like sustained activation pattern but greater increases in connectivity performed better. Taken together, Paper 1 demonstrated that children managed increased sustained control demands during task switching in at least two ways, (1) increased activation in the brain regions also recruited by adults, or (2) increased connectivity with additional brain regions in the lateral prefrontal cortex (lPFC), thus potentially relying on additional metacontrol processes. One factor proposed to contribute to age-related improvements in task switching is an increasing ability to represent multiple rules and effectively update these when necessary. Using the same sample of children and adults, Paper 2 investigated this hypothesis using multivariate pattern analysis to elucidate the role of neural task-set representations on age differences in task switching. Results demonstrated that neural activation patterns on switch trials held less information regarding the currently relevant task than on repeat trials. Intriguingly, this switch-related reduction of task-set distinctiveness did not differ between children and adults, showing a striking level of maturity in the neural representation of task sets and raising the question which other mechanisms contributed to greater switch costs in late childhood. Building on the insights from Papers 1 and 2, Paper 3 explored how the neural and cognitive processes supporting the development of task switching changed in children that either trained intensive single tasking or intensive task switching over nine weeks. Using drift-diffusion models and fMRI data, I investigated how cognitive and neural processes during task switching changed with training. Faster accumulation of evidence as indicated by increased drift rates, along with decreased activation in the lPFC suggested more efficient rule processing with intensive task-switching training. The accompanying changes in boundary separation further suggested strategy changes, such that children may have allocated cognitive control resources differently, potentially because of improvements in monitoring task demands, enabling them to match their performance accordingly. Taken together, the empirical findings of this dissertation converge to reveal a consistent picture of increasingly more refined recruitment of frontoparietal brain regions, in particular the lPFC, both with age and with intensive training during childhood. They thus raise questions on the role of hierarchical cognitive control and metacontrol processes for developmental improvements of cognitive flexibility. The novel insights into task switching presented in this dissertation thus further our understanding of development and learning in cognitive control, and cognition more generally.Die Fähigkeit zur Anpassung unseres Verhaltens an wechselnde kontextuelle Anforderungen bildet eine wichtige Voraussetzung für die flexible und effiziente Verfolgung von Handlungszielen. Mit zunehmendem Alter gelingt es Kindern besser, zwischen verschiedenen Aufgaben zu wechseln. Im Vergleich zu Erwachsenen lassen sich aber auch am Ende der Kindheit noch Effizienzunterschiede im Aufgabenwechsel nachweisen. Angesichts der hohen Bedeutung kognitiver Flexibilität sind Versuche unternommen worden, die kognitive Flexibilität bei Kindern durch Training zu verbessern. Die theoretische Begründung dieser Trainingsstudien war häufig wenig präzise und die Befundlage entsprechend unklar. In meiner Dissertation gehe ich daher einer überwiegend grundlagenwissenschaftlichen und vorgelagerten Fragestellung nach: Ich untersuche auf behavioraler und neuronaler Ebene die Gründe von Altersunterschieden und Trainingszugewinnen in der kognitiven Flexibilität. Zu diesem Zweck untersuche ich 8–11-jährige Kinder mithilfe von Verhaltensdaten sowie von Bildgebungsdaten der funktionellen Magnetresonanztomographie bezüglich der univariaten Aktivierung, der Konnektivität und der multivariaten Dekodierung von Repräsentationen. In den Schriften 1 und 2 gehe ich zunächst der Frage nach, welche neuronalen Prozesse die Entwicklung der kognitiven Flexibilität unterstützen. Schrift 3 untersucht, wie sich Verhalten und neuronale Prozesse trainingsbedingt verändern. Den drei Schriften habe ich eine Synopse vorangestellt, in der ich den theoretischen Rahmen der Dissertation erläutere und die Befundlage zusammenfasse. Abschließend fasse ich die Ergebnisse meiner Dissertation zusammen und erörtere ihren Beitrag zum Stand der Forschung. Die Kosten eines Aufgabenwechsels zeigen sich in geringerer Genauigkeit und längeren Reaktionszeiten. Dabei stellt der Aufgabenwechsel im Gegensatz zur isolierten Ausführung einzelner Aufgaben höhere Anforderungen an die Aufrechterhaltung und Handhabung mehrerer Aufgabensets (engl. task sets), die mit sogenannten Mischkosten einhergehen. Darüber hinaus stellt der Wechsel zu einer anderen Aufgabe im Vergleich zur Wiederholung derselben Aufgabe erhöhte Anforderungen an die Hemmung des zuvor relevanten Aufgabensets und die Aktualisierung des nun relevanten Aufgabensets, die zu sogenannten Wechselkosten führen. Vorliegende Befunde zeigen, dass Mischkosten und Wechselkosten unterschiedliche Muster von Altersunterschieden aufweisen; dabei nähern sich die Wechselkosten von Kindern dem Niveau von Erwachsenen früher an als die Mischkosten. Die vorliegende Dissertation baut auf diesen Befunden auf und untersucht die Gründe der unterschiedlichen Entwicklungsverläufe von Misch- und Wechselkosten auf behavioraler und neuronaler Ebene. In Schrift 1 untersuche ich den Beitrag andauernder und vorübergehender Kontrollprozesse zu Altersunterschieden in Misch- und Wechselkosten. Die Ergebnisse zeigen, dass die Altersunterschiede zwischen Kindern und Erwachsenen in Mischkosten und der damit zusammenhängenden andauernden Aktivierung größer sind als bei den Wechselkosten und der vorübergehenden Aktivierung. Darüber lassen die Ergebnisse von Schrift 1 Rückschlüsse auf einen möglichen alternativen Mechanismus zu, mit dem Kinder erhöhte Anforderungen an die andauernde Kontrolle bewältigen: Kinder, deren andauerndes Aktivierungsmuster weniger dem der Erwachsenen ähnelte, die dafür aber eine stärkere Zunahme der Konnektivität zeigten, wiesen geringere Mischkosten auf. Insgesamt konnte ich in Schrift 1 meiner Dissertation somit zeigen, dass Kinder erhöhte Anforderungen an andauernde Kontrolle während des Aufgabenwechsels auf mindestens zwei Arten bewältigen: (1) durch die erhöhte Aktivierung von Hirnregionen, die auch bei Erwachsenen rekrutiert werden, oder (2) durch erhöhte Konnektivität mit weiteren Hirnregionen im lateralen präfrontalen Kortex, die möglicherweise auf die Beteiligung zusätzlicher Prozesse der Handlungssteuerung hinweisen. Die Zunahme der Fähigkeit zur Repräsentation und handlungsdienlichen Aktivierung mehrerer Regeln könnte einen wichtigen Grund für die zunehmende Genauigkeit und Schnelligkeit des Aufgabenwechsels darstellen. In Schrift 2 habe ich diese Hypothese mit Hilfe einer multivariaten Musteranalyse untersucht, mit der sich der Beitrag der neuronalen Repräsentation von Aufgabenset zu Altersunterschieden im Aufgabenwechsel bestimmen lässt. Die Ergebnisse zeigen, dass die neuronalen Aktivierungsmuster bei Aufgaben, denen ein Wechsel von einem Aufgabenset zu einem anderen vorausgeht, weniger Informationen über die aktuell relevante Aufgabe enthielten als bei Aufgaben, denen kein Wechsel vorausgeht. Interessanterweise ließen sich zwischen Kindern und Erwachsenen keine Unterschiede in der wechselbedingten Verringerung der Repräsentationsgüte nachweisen. Dies lässt auf einen bemerkenswerten Reifegrad der neuronalen Repräsentation von Aufgabensets bei den Kindern schließen und wirft die Frage auf, welche weiteren Mechanismen zu den im Vergleich zum Erwachsenenalter erhöhten Wechselkosten in der späten Kindheit beitragen. Aufbauend auf den zuvor gewonnenen Erkenntnissen gilt Schrift 3 meiner Dissertation der detaillierten Untersuchung trainingsbedingter Veränderungen von Aufgabenwechselkosten in der späten Kindheit. Mithilfe von Drift-Diffusionsmodellen habe ich trainingsbedingte Veränderungen in den kognitiven Prozesses des Aufgabenwechsel untersucht. Hier zeigte sich, dass intensives Training des Aufgabenwechsels zu einer schnelleren Evidenzakkumulation für die korrekte Antwort führt. Ein schnelleres Akkumulieren von Evidenz, zusammen mit einer Reduktion der Aktivierung im lateralen präfrontalen Kortex deutet auf eine effizientere Regelverarbeitung durch Training hin. Diese Veränderungen gingen außerdem mit Strategieänderungen einher, sodass die Kinder ihre kognitiven Kontrollressourcen anders zugewiesen haben könnten, möglicherweise aufgrund von Verbesserungen bei der Überwachung der Anforderungen und der entsprechenden Anpassung ihrer Leistung. Zusammengenommen ergeben die empirischen Befunde meiner Dissertation das Bild einer zunehmend verfeinerten Beteiligung frontoparietaler Hirnregionen am Aufgabenwechsel. Dabei scheint der laterale präfrontale Kortex eine wichtige Rolle zu spielen, und zwar sowohl in Bezug auf Altersunterschiede zwischen Kindern und Erwachsenen als auch in Bezug auf trainingsbedingte Veränderungen bei den Kindern. Dies unterstreicht die Bedeutung des lateralen präfrontalen Kortex für hierarchische Kontrollprozesse sowie deren Beitrag zur Entwicklung der kognitiven Flexibilität im Kindesalter. Die Ergebnisse meiner Dissertation erweitern das Verständnis des Beitrags kognitiver Kontrollprozesse zur kognitiven Entwicklung. Sie bilden zugleich eine Grundlage für weiterführende Untersuchungen des Zusammenspiels erfahrungsbedingter und reifungsbedingter Einflüsse auf die kognitive Entwicklung im Kindesalter

Inefficient cognitive control in adult ADHD: evidence from trial-by-trial Stroop test and cued task switching performance

<p>Abstract</p> <p>Background</p> <p>Contemporary neuropsychological models of ADHD implicate impaired cognitive control as contributing to disorder characteristic behavioral deficiencies and excesses; albeit to varying degrees. While the traditional view of ADHD postulates a core deficiency in cognitive control processes, alternative dual-process models emphasize the dynamic interplay of bottom-up driven factors such as activation, arousal, alerting, motivation, reward and temporal processing with top-down cognitive control. However, neuropsychological models of ADHD are child-based and have yet to undergo extensive empirical scrutiny with respect to their application to individuals with persistent symptoms in adulthood. Furthermore, few studies of adult ADHD samples have investigated two central cognitive control processes: interference control and task-set coordination. The current study employed experimental chronometric Stroop and task switching paradigms to investigate the efficiency of processes involved in interference control and task-set coordination in ADHD adults.</p> <p>Methods</p> <p>22 adults diagnosed with persistent ADHD (17 males) and 22 matched healthy control subjects performed a manual trial-by-trial Stroop color-word test and a blocked explicitly cued task switching paradigm. Performance differences between neutral and incongruent trials of the Stroop task measured interference control. Task switching paradigm manipulations allowed for measurement of transient task-set updating, sustained task-set maintenance, preparatory mechanisms and interference control. Control analyses tested for the specificity of group × condition interactions.</p> <p>Results</p> <p>Abnormal processing of task-irrelevant stimulus features was evident in ADHD group performance on both tasks. ADHD group interference effects on the task switching paradigm were found to be dependent on the time allotted to prepare for an upcoming task. Group differences in sustained task-set maintenance and transient task-set updating were also found to be dependent on experimental manipulation of task preparation processes. With the exception of Stroop task error rates, all analyses revealed generally slower and less accurate ADHD group response patterns.</p> <p>Conclusion</p> <p>The current data obtained with experimental paradigms deliver novel evidence of inefficient interference control and task-set coordination in adults with persistent ADHD. However, all group differences observed in these central cognitive control processes were found to be partially dependent on atypical ADHD group task preparation mechanisms and/or response inconsistency. These deficiences may have contributed not only to inefficient cognitive control, but also generally slower and less accurate ADHD group performance. Given the inability to dissociate these impairments with the current data, it remains inconclusive as to whether ineffecient cognitive control in the clinical sample was due to top-down failure or bottom-up engagement thereof. To clarify this issue, future neuropsychological investigations are encouraged to employ tasks with significantly more trials and direct manipulations of bottom-up mechanisms with larger samples.</p

Self-Ordered Search: A Novel fMRI Task to Study Working Memory in Children with Catastrophic Disease

Children treated for brain tumors are at increased risk for developing cognitive deficits. The self-ordered search (SOS) is a computerized neuropsychological test used to investigate working memory, a cognitive system whose function is integral to many high level cognitive processes. Functional-MRI (fMRI) provides important opportunities to characterize neural correlates of SOSperformance non-invasively. Implementation of the SOStask presents challenges in the unique environment of the MRI scanner. First, SOSrequires participants to select a single stimulus from a set. Second, SOSis a behaviorally driven task that entails variable event timing among participants which complicates group analysis of fMRI data. The work presented here consists of the implementation, validation and application of the SOSfor fMRI and associated analysis techniques. Eye-tracking with a MRI-safe response device was used as an interface for the fMRI task, allowing the participant to select an individual stimulus from a two-dimensional array. Performance information was used to generate individual subject design matrices for fMRI analysis, preserving important behaviorally measures (time to completion). Healthy volunteers and patients treated for childhood brain tumors performed the SOS task and N-back task, a commonly used working memory task for fMRI. The eye-tracking interface performed well after initial problems with equipment and calibration routine were solved. Activation patterns identified by general linear model (GLM) analysis were similar between SOS and N-back tasks and included dorsolateral prefrontal cortex, ventral prefrontal cortex, dorsal cingulate, bilateral premotor, and parietal areas. Independent component analysis identified task-correlated components that were consistent with the GLM. Increasing activation across the general network was associated with fewer errors during the N-back task. Differences in activation between patient group and healthy group were identified in the parietal and retrosplenial cortex. Analysis of the performance data suggests differences between the healthy and patient groups. Our novel eye-tracking interface provides a natural interface that controls for movement and motor planning associated with complex response devices. The SOS for fMRI provides a new tool that will allow us to investigate deficits of working memory in children treated for brain tumors