Tracking Inhibitory Control in Youth With ADHD: A Multi-Modal Neuroimaging Approach.

Background: A decreased ability to inhibit a speeded motor response is a well-studied deficit in Attention Deficit Hyperactivity Disorder (ADHD), and has been proposed as an endophenotype. Inhibitory control has been assessed reliably with the Stop Signal Task (SST) and is associated with prior documented differences in regional brain function using f-MRI. Here, we advance on these findings by examining their structural connectivity and white matter integrity with the goal of identifying a network underlying a core cognitive deficit in ADHD.

Functional neuroanatomical substrates of altered reward processing in major depressive disorder revealed by a dopaminergic probe.

Context: The pathophysiology of major depressive disorder (MDD) includes disturbances in several neuroanatomical substrates and neurotransmitter systems. The challenge is to elucidate the brain mechanisms of MDD behavioral symptoms, chiefly those of anhedonia.

Objectives: To visualize the neuroanatomical substrates implicated in altered reward processing in MDD, using functional magnetic resonance imaging in combination with a dopaminergic probe (a 30-mg dose of oral dextroamphetamine sulfate) to stimulate the brain reward system; and to test the hypothesis that a hypersensitive response to dextroamphetamine in MDD involves the prefrontal cortex and the striatum.

Neurodevelopmental liabilities in alcohol dependence: central serotonin and dopamine dysfunction.

Alcoholism is a complex disorder with symptoms ranging from abuse to dependence, often comorbid with depression, antisocial personality, or anxiety. Neurodevelopmental causes of the disorder are unknown but inferences are possible from current knowledge. Neurobiological studies implicate multiple brain changes, which may be characterized as premorbid or morbid.

Brain reward system activity in major depression and comorbid nicotine dependence.

Major depressive disorder (MDD) and nicotine dependence are highly comorbid. MDD patients may use nicotine to ameliorate depressive symptoms. The pathophysiology of the comorbidity of these two disorders is unknown.

Probing brain reward system function in major depressive disorder: altered response to dextroamphetamine.

Background: The state of the brain reward system in major depressive disorder was assessed with dextroamphetamine, which probes the release of dopamine within the mesocorticolimbic system, a major component of the brain reward system, and produces measurable behavioral changes, including rewarding effects (eg, euphoria). We hypothesized that depressed individuals would exhibit an altered response to dextroamphetamine due to an underlying brain reward system dysfunction reflected by anhedonic symptoms.

Methods: In a double-blind, placebo-controlled, randomized, parallel study, the behavioral and physiological effects of a single 30-mg dose of oral dextroamphetamine sulfate were measured.