Publications by authors named "Michael G Hardin"

Adolescence is a transitional period in development that is marked by a distinct, typical behavioral profile of high rates of exploration, novelty-seeking, and emotional lability. While these behaviors generally assist the adolescent transition to independence, they can also confer vulnerability for excessive risk-taking and psychopathology, particularly in the context of specific environmental or genetic influences. As prevention research depends on the identification of targets of vulnerability, the following review will discuss the interplay among motivational systems including reward-related, avoidance-related, and regulatory processes in typical and atypical adolescent development.

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Little is known about how steroid hormones contribute to the beneficial effect of incentives on cognitive control during adolescent development. In this study, 27 adolescents with Congenital Adrenal Hyperplasia (CAH, mean age 15.6 years, 12 female), a disorder of cortisol deficiency and androgen excess, and 36 healthy participants (mean age 16.

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Major depression is associated with a wide range of neurobiological disturbances, including anomalies in the structure and function of cortical and subcortical gray matter and dysregulation of the HPA axis. In this chapter, we review research demonstrating that many of these abnormalities are also present in never-depressed offspring of adults with recurrent depression and discuss how such findings might reflect dysfunctional neuroregulatory systems that precede the onset of this disorder. We also briefly discuss candidate genes and environmental factors that have been posited to be directly involved in the transmission of neural and HPA-axis abnormalities from depressed parents to their offspring, and we review how, by obtaining a better understanding of the neurobiological markers of depression risk, we can facilitate the development of targeted strategies for the prevention and treatment of major depression.

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The monetary incentive delay (MID) task (Knutson, 2000) is an imaging paradigm used to measure neural activity of incentive receipt anticipation. The task reliably elicits striatal activation and is commonly used with both adult and adolescent populations, but is not designed for use with children. In the current article, we present data on the newly designed 'piñata task' a child-friendly analog of the MID task.

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Objective: Early-life stress (ES) such as adoption, change of caregiver, or experience of emotional neglect may influence the way in which affected individuals respond to emotional stimuli of positive or negative valence. These modified responses may stem from a direct alteration of how emotional stimuli are coded, and/or the cognitive function implicated in emotion modulation, such as self-regulation or inhibition. These ES effects have been probed on tasks either targeting reward and inhibitory function.

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Background: Anxiety disorders are highly prevalent in children and adolescents, and are associated with aberrant emotion-related attention orienting and inhibitory control. While recent studies conducted with high-trait anxious adults have employed novel emotion-modified antisaccade tasks to examine the influence of emotional information on orienting and inhibition, similar studies have yet to be conducted in youths.

Methods: Participants were 22 children/adolescents diagnosed with an anxiety disorder, and 22 age-matched healthy comparison youths.

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The adolescent period is characterized by substantial behavioral changes, including increases in novelty-seeking and risk-taking, which may facilitate substance use and experimentation. These behavioral changes co-occur with widespread structural and functional neural developments. Ontogenic changes affecting the neural circuitry subserving inhibitory control and reward-related processes are particularly relevant to adolescent risk-taking behavior.

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Pediatric bipolar disorder is a severe and impairing illness. Characterizing the impact of pediatric bipolar disorder on cognitive function might aid in understanding the phenomenology of the disorder. While previous studies of pediatric bipolar disorder have reported deficits in cognitive control and reward behavior, little is understood about how affective processes influence behavioral control.

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Background: Anxiety disorders are characterized by elevated, sustained responses to threat, that manifest as threat attention biases. Recent evidence also suggests exaggerated responses to incentives. How these characteristics influence cognitive control is under debate and is the focus of the present study.

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The emotional significance of objects and events depends on the context in which they occur. Using functional magnetic resonance imaging, we examined the modulation of neural responses to monetary outcomes while subjects performed a decision-making task in a positive and a negative economic context. Neural responses indicated a relative regional specialization in the neural coding of outcome valence and followed three distinct patterns.

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Economic decision-making involves the weighting of magnitude and probability of potential gains/losses. While previous work has examined the neural systems involved in decision-making, there is a need to understand how the parameters associated with decision-making (e.g.

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Background: Developmental changes in cognitive and affective processes contribute to adolescent risk-taking behavior, emotional intensification, and psychopathology. The current study examined adolescent development of cognitive control processes and their modulation by incentive, in health and psychopathology. Predictions include 1) better cognitive control in adults than adolescents, and in healthy adolescents than anxious and depressed adolescents, and 2) a stronger influence of incentives in adolescents than adults, and in healthy adolescents than their depressed and anxious counterparts.

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Behavioral inhibition (BI) is a risk factor for anxiety disorders. While the two constructs bear behavioral similarities, previous work has not extended these parallels to the neural level. This study examined amygdala reactivity during a task previously used with clinically anxious adolescents.

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The temperamental style of behavioral inhibition has been characterized by exaggerated behavioral and neural responses to cues signaling threat. Virtually no work, however, has addressed whether behavioral inhibition may also confer heightened brain activation in response to positively valenced incentives. We used event-related functional MRI (fMRI) and a monetary incentive delay task to examine whether the neural response to incentives is also greater in adolescents characterized as behaviorally inhibited early in life compared with those characterized as non-inhibited.

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Adolescence is characterized by increased risk-taking and sensation-seeking, presumably brought about by developmental changes within reward-mediating brain circuits. A better understanding of the neural mechanisms underlying reward-seeking during adolescence can have critical implications for the development of strategies to enhance adolescent performance in potentially dangerous situations. Yet little research has investigated the influence of age on the modulation of behavior by incentives with neuroscience-based methods.

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Few studies have examined underlying mechanisms linking social behavior, motivated behavior, and reward and punishment systems. The current study was designed to investigate these mechanisms by examining responses to both rewarding and punishing non-social stimuli in shy and non-shy adults. Ninety-three participants, comprising three social behavior groups (Shy, Non-shy, Control) completed the Monetary Incentive Delay task.

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