Oral methylphenidate normalizes cingulate activity in cocaine addiction during a salient cognitive task

Abstract

Anterior cingulate cortex (ACC) hypoactivations during cognitive demand are a hallmark deficit in drug addiction. Methylphenidate (MPH) normalizes cortical function, enhancing task salience and improving associated cognitive abilities, in other frontal lobe pathologies; however, in clinical trials, MPH did not improve treatment outcome in cocaine addiction. We hypothesized that oral MPH will attenuate ACC hypoactivations and improve associated performance during a salient cognitive task in individuals with cocaine-use disorders (CUD). In the current functional MRI study, we used a rewarded drug cue-reactivity task previously shown to be associated with hypoactivations in both major ACC subdivisions (implicated in default brain function) in CUD compared with healthy controls. The task was performed by 13 CUD and 14 matched healthy controls on 2 d: after ingesting a single dose of oral MPH (20 mg) or placebo (lactose) in a counterbalanced fashion. Results show that oral MPH increased responses to this salient cognitive task in both major ACC subdivisions (including the caudal-dorsal ACC and rostroventromedial ACC extending to the medial orbitofrontal cortex) in the CUD. These functional MRI results were associated with reduced errors of commission (a common impulsivity measure) and improved task accuracy, especially during the drug (vs. neutral) cue-reactivity condition in all subjects. The clinical application of such MPH-induced brain-behavior enhancements remains to be tested.D rug addiction is a chronically relapsing disorder associated with dysregulated dopaminergic neurotransmission as well as functional impairments in the brain regions innervated by dopamine [e.g., the prefrontal cortex (PFC)] (1, 2). Psychostimulants such as cocaine have high abuse and dependence potential because of their ability to increase dopamine in limbic brain regions. Similarly to cocaine, methylphenidate (MPH; e.g., Ritalin) blocks the dopamine transporter increasing extracellular dopamine. However, although speed of uptake of both drugs is similar, rate of clearance of MPH from the brain is substantially slower than that for cocaine (90-vs. 20-min half-life), and these slower pharmacokinetic properties may contribute to the lower abuse potential for MPH (1). Both these neuropharmacological mechanisms, interference with the binding of the drug to its target and different (i.e., slower) pharmacokinetics, proved valuable in the management of heroin (e.g., with methadone and buprenorphine) and nicotine addiction (e.g., with nicotine patch and nicotine gum) (3). In contrast, adapting a similar pharmacological strategy (use of stimulant medications such as MPH) in individuals with cocaine-use disorders (CUD) did not decrease cocaine use or prevent relapse (1).Nevertheless, oral MPH decreases abnormal risk taking in patients with frontotemporal dementia (4) and children with attention deficit hyperactivity disorder (ADHD) (5). Furthermore, when on stimulant medication (including MPH), youth with ADHD showed a trend to improved inhibitor...

Neuroimaging Evidence of Altered Fronto-Cortical and Striatal Function after Prolonged Cocaine Self-Administration in the Rat

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Extrastriatal dopaminergic abnormalities of DA homeostasis in Parkinson's patients with medication-induced pathological gambling: A [11C] FLB-457 and PET study

“…Thus, if increased BP indicates lower basal DA levels, this implies that low DA modulation of the ACC contributes to the impulsive personality trait, perhaps by impairing inhibitory control. Indeed, a previous fMRI study found that oral methlyphenidate, which increases DA levels, reduced behavioural impulsivity in cocaine addicted and control subjects, and was associated with normalised ACC activity in the cocaine addicted group (Goldstein et al, 2010). Low DA tone in this area has also been associated with apathy (Thobois et al, 2010), which would seem incongruous with our suggestion that it is associated with impulsivity.…”

fMRI Analysis with Sparse Weisfeiler-Lehman Graph Statistics

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