Catherine Insel

Curbing Craving Behavioral and Brain Evidence That Children Regulate Craving When Instructed to Do So but Have Higher Baseline Craving Than Adults

Although one third of children and adolescents are overweight or obese, developmental changes in food craving and the ability to regulate craving remain poorly understood. We addressed this knowledge gap by examining behavioral and neural responses to images of appetizing unhealthy foods in individuals ages 6 through 23 years. On close trials (assessing unregulated craving), participants focused on a pictured food’s appetitive features. On far trials (assessing effortful regulation), participants focused on a food’s visual features and imagined that it was farther away. Across conditions, older age predicted less craving, less striatal recruitment, greater prefrontal activity, and stronger frontostriatal coupling. When effortfully regulating their responses to the images, all participants reported less craving and exhibited greater recruitment of lateral prefrontal cortex and less recruitment of ventromedial prefrontal cortex. Greater body mass predicted less regulation-related prefrontal activity, particularly among children. These results suggest that children experience stronger craving than adults but can also effectively regulate craving. Moreover, the mechanisms underlying regulation may differ for heavy and lean children.

Neural Correlates of Impaired Cognitive Control over Working Memory in Schizophrenia

BACKGROUND One of the most common deficits in patients with schizophrenia (SZ) is in working memory (WM), which has wide-reaching impacts across cognition. However, previous approaches to studying WM in SZ have used tasks that require multiple cognitive-control processes, making it difficult to determine which specific cognitive and neural processes underlie the WM impairment. METHODS We used functional magnetic resonance imaging to investigate component processes of WM in SZ. Eighteen healthy controls (HCs) and 18 patients with SZ performed an item-recognition task that permitted separate neural assessments of 1) WM maintenance, 2) inhibition, and 3) interference control in response to recognition probes. RESULTS Before inhibitory demands, posterior ventrolateral prefrontal cortex (VLPFC), an area involved in WM maintenance, was activated to a similar degree in both HCs and patients, indicating preserved maintenance operations in SZ. When cued to inhibit items from WM, HCs showed reduced activation in posterior VLPFC, commensurate with appropriately inhibiting items from WM. However, these inhibition-related reductions were absent in patients. When later probed with items that should have been inhibited, patients showed reduced behavioral performance and increased activation in mid-VLPFC, an area implicated in interference control. A mediation analysis indicated that impaired inhibition led to increased reliance on interference control and reduced behavioral performance. CONCLUSIONS In SZ, impaired control over memory, manifested through proactive inhibitory deficits, leads to increased reliance on reactive interference-control processes. The strain on interference-control processes results in reduced behavioral performance. Thus, inhibitory deficits in SZ may underlie widespread impairments in WM and cognition.

The transition from childhood to adolescence is marked by a general decrease in amygdala reactivity and an affect-specific ventral-to-dorsal shift in medial prefrontal recruitment

Understanding how and why affective responses change with age is central to characterizing typical and atypical emotional development. Prior work has emphasized the role of the amygdala and prefrontal cortex (PFC), which show age-related changes in function and connectivity. However, developmental neuroimaging research has only recently begun to unpack whether age effects in the amygdala and PFC are specific to affective stimuli or may be found for neutral stimuli as well, a possibility that would support a general, rather than affect-specific, account of amygdala-PFC development. To examine this, 112 individuals ranging from 6 to 23 years of age viewed aversive and neutral images while undergoing fMRI scanning. Across age, participants reported more negative affect and showed greater amygdala responses for aversive than neutral stimuli. However, children were generally more sensitive to both neutral and aversive stimuli, as indexed by affective reports and amygdala responses. At the same time, the transition from childhood to adolescence was marked by a ventral-to-dorsal shift in medial prefrontal responses to aversive, but not neutral, stimuli. Given the role that dmPFC plays in executive control and higher-level representations of emotion, these results suggest that adolescence is characterized by a shift towards representing emotional events in increasingly cognitive terms.

Antipsychotic dose modulates behavioral and neural responses to feedback during reinforcement learning in schizophrenia

Schizophrenia is characterized by an abnormal dopamine system, and dopamine blockade is the primary mechanism of antipsychotic treatment. Consistent with the known role of dopamine in reward processing, prior research has demonstrated that patients with schizophrenia exhibit impairments in reward-based learning. However, it remains unknown how treatment with antipsychotic medication impacts the behavioral and neural signatures of reinforcement learning in schizophrenia. The goal of this study was to examine whether antipsychotic medication modulates behavioral and neural responses to prediction error coding during reinforcement learning. Patients with schizophrenia completed a reinforcement learning task while undergoing functional magnetic resonance imaging. The task consisted of two separate conditions in which participants accumulated monetary gain or avoided monetary loss. Behavioral results indicated that antipsychotic medication dose was associated with altered behavioral approaches to learning, such that patients taking higher doses of medication showed increased sensitivity to negative reinforcement. Higher doses of antipsychotic medication were also associated with higher learning rates (LRs), suggesting that medication enhanced sensitivity to trial-by-trial feedback. Neuroimaging data demonstrated that antipsychotic dose was related to differences in neural signatures of feedback prediction error during the loss condition. Specifically, patients taking higher doses of medication showed attenuated prediction error responses in the striatum and the medial prefrontal cortex. These findings indicate that antipsychotic medication treatment may influence motivational processes in patients with schizophrenia.

Patients with schizophrenia are impaired when learning in the context of pursuing rewards

Recent findings suggest that patients with schizophrenia have a probabilistic learning impairment that is selective to learning from positive, relative to negative, feedback (Gold et al., 2012), and is more compromised in those with worse negative symptoms (Waltz et al., 2010). This is consistent with evidence linking motivational and affective symptoms of schizophrenia with dysfunctional signaling across neural systems in the dopamine-mediated reward network (Gold et al., 2008; Waltz et al., 2009; Maia and Frank, 2011). While prior studies have examined this selective learning impairment using tasks comprised of intermixed positive and negative trial types that collapse feedback and reward outcome together, an extension of this work would aim to isolate and examine the impact of motivational context. As such, we designed a task, presented in two separate Gain and Loss conditions, in which feedback was held constant, and the outcome was varied with respect to accumulating gains or avoiding losses. It was hypothesized that there would be an effect ofmotivational context, such that patients would perform better in the Loss condition despite identical types of feedback.

Charting the expansion of strategic exploratory behavior during adolescence.

Although models of exploratory decision making implicate a suite of strategies that guide the pursuit of information, the developmental emergence of these strategies remains poorly understood. This study takes an interdisciplinary perspective, merging computational decision making and developmental approaches to characterize age-related shifts in exploratory strategy from adolescence to young adulthood. Participants were 149 12–28-year-olds who completed a computational explore–exploit paradigm that manipulated reward value, information value, and decision horizon (i.e., the utility that information holds for future choices). Strategic directed exploration, defined as information seeking selective for long time horizons, emerged during adolescence and maintained its level through early adulthood. This age difference was partially driven by adolescents valuing immediate reward over new information. Strategic random exploration, defined as stochastic choice behavior selective for long time horizons, was invoked at comparable levels over the age range, and predicted individual differences in attitudes toward risk taking in daily life within the adolescent portion of the sample. Collectively, these findings reveal an expansion of the diversity of strategic exploration over development, implicate distinct mechanisms for directed and random exploratory strategies, and suggest novel mechanisms for adolescent-typical shifts in decision making.

Adolescent Development of Value-Guided Goal Pursuit

Adolescents are challenged to orchestrate goal-directed actions in increasingly independent and consequential ways. In doing so, it is advantageous to use information about value to select which goals to pursue and how much effort to devote to them. Here, we examine age-related changes in how individuals use value signals to orchestrate goal-directed behavior. Drawing on emerging literature on value-guided cognitive control and reinforcement learning, we demonstrate how value and task difficulty modulate the execution of goal-directed action in complex ways across development from childhood to adulthood. We propose that the scope of value-guided goal pursuit expands with age to include increasingly challenging cognitive demands, and scaffolds on the emergence of functional integration within brain networks supporting valuation, cognition, and action.

Development of corticostriatal connectivity constrains goal-directed behavior during adolescence

When pursuing high-value goals, mature individuals typically titrate cognitive performance according to environmental demands. However, it remains unclear whether adolescents similarly integrate value-based goals to selectively enhance goal-directed behavior. We used a value-contingent cognitive control task during fMRI to assess how stakes—the value of a prospective outcome—modulate flexible goal-directed behavior and underlying neurocognitive processes. Here we demonstrate that while adults enhance performance during high stakes, adolescents perform similarly during low and high stakes conditions. The developmental emergence of value-contingent performance is mediated by connectivity between the striatum and prefrontal cortex; this connectivity selectively increases during high stakes and with age. These findings suggest that adolescents may not benefit from high stakes to the same degree adults do—a behavioral profile that may be constrained by ongoing maturation of corticostriatal connectivity. We propose that late development of corticostriatal connectivity sets the stage for optimal goal-directed behavior.Adults adjust their cognitive performance according to the value of the outcome, but it is unclear whether adolescents do too. Here, authors show that adolescents do not adjust their cognitive effort according to value, and that this ability is mediated by connectivity between the striatum and prefrontal cortex.

Asymmetric neural tracking of gain and loss magnitude during adolescence

Abstract Adolescence has been characterized as a developmental period of heightened reward seeking and attenuated aversive processing. However, it remains unclear how the neural bases of distinct outcome valuation processes shift during this stage of the lifespan. A total of 74 participants ranging in age from 13 to 20 years completed a value‐modulated functional magnetic resonance imaging (fMRI) task in which participants earn low and high magnitude monetary outcomes to test whether gain and loss magnitude tracking—the neural representation of relative value in context—change differentially over this age span. Results revealed that gain and loss magnitude tracking follow asymmetric developmental trajectories. Gain magnitude tracking is elevated in the striatum during early adolescence and then decreases with age. By contrast, loss magnitude tracking in the anterior insula follows a quadratic pattern, undergoing a temporary attenuation during mid‐late adolescence. A typical comparison of gain vs loss outcomes (collapsing over magnitude effects) showed robust activity across a suite of brain regions sensitive to value based on prior work including the ventral striatum, but they exhibited no changes with age. These findings suggest that value coding subprocesses follow divergent developmental paths across adolescence, which may contribute to normative shifts in adolescent motivated behavior.

Neural substrates of the influence of emotional cues on cognitive control in risk-taking adolescents

Adolescence is a period characterised by increases in risk-taking. This behaviour has been associated with an imbalance in the integration of the networks involved in cognitive control and motivational processes. We examined whether the influence of emotional cues on cognitive control differs between adolescents who show high or low levels of risk-taking behaviour. Participants who scored especially high or low on a risky decision task were subsequently administered an emotional go/no-go fMRI task comprising angry, happy and calm faces. Both groups showed decreased cognitive control when confronted with appetitive and aversive emotional cues. Activation in the inferior frontal gyrus (IFG) increased in line with the cognitive control demands of the task. Though the risk taking groups did not differ in their behavioural performance, functional connectivity analyses revealed the dorsal striatum plays a more central role in the processing of cognitive control in high than low risk-takers. Overall, these findings suggest that variance in fronto-striatal circuitry may underlie individual differences in risk-taking behaviour.