Motivational factors modulate left frontoparietal network during cognitive control in cocaine addiction.

Cocaine addiction is characterized by alterations in motivational and cognitive processes involved in goal-directed behavior. Recent studies have shown that addictive behaviors can be attributed to alterations in the activity of large functional networks. The aim of this study was to investigate how cocaine addiction affected the left frontoparietal network during goal-directed behavior in a stop-signal task (SST) with reward contingencies by correct task performance. Twenty-eight healthy controls (HC) and 30 abstinent cocaine-dependent patients (ACD) performed SST with monetary reward contingencies while undergoing a functional magnetic resonance imaging scan. The results showed that the left frontoparietal network (FPN) displayed an effect of cocaine addiction depending on reward contingencies rather than inhibition accuracy; and, second, we observed a negative correlation between dependence severity and the modulation of the left FPN network by the monetary reward in ACD. These findings highlight the role of the left FPN in the motivational effects of cocaine dependence.

Reward Contingencies Improve Goal-Directed Behavior by Enhancing Posterior Brain Attentional Regions and Increasing Corticostriatal Connectivity in Cocaine Addicts.

The dopaminergic system provides the basis for the interaction between motivation and cognition. It is triggered by the possibility of obtaining rewards to initiate the neurobehavioral adaptations necessary to achieve them by directing the information from motivational circuits to cognitive and action circuits. In drug addiction, the altered dopamine (DA) modulation of the meso-cortico-limbic reward circuitry, such as the prefrontal cortex (PFC), underlies the disproportionate motivational value of drug use at the expense of other non-drug reinforcers and the user's loss of control over his/her drug intake. We examine how the magnitude of the reward affects goal-directed processes in healthy control (HC) subjects and abstinent cocaine dependent (ACD) patients by using functional magnetic resonance imaging (fMRI) during a counting Stroop task with blocked levels of monetary incentives of different magnitudes (€0, €0.01, €0.5, €1 or €1.5). Our results showed that increasing reward magnitude enhances (1) performance facilitation in both groups; (2) left dorsolateral prefrontal cortex (DLPFC) activity in HC and left superior occipital cortex activity in ACD; and (3) left DLPFC and left putamen connectivity in ACD compared to HC. Moreover, we observed that (4) dorsal striatal and pallidum activity was associated with craving and addiction severity during the parametric increases in the monetary reward. In conclusion, the brain response to gradients in monetary value was different in HC and ACD, but both groups showed improved task performance due to the possibility of obtaining greater monetary rewards.

[Efficacy of oxcarbazepine treatment in patients diagnosed with cocaine abuse/dependence]. / Utilidad del tratamiento con oxcarbacepina en pacientes con diagnostico de trastorno por abuso/dependencia de cocaina.

UNLABELLED: To assess the efficacy of oxcarbazepine in the treatment of cocaine addiction and its influence on impulsivity and craving in cocaine addicts. METHODOLOGY: A prospective, observational and clinical study was conducted in patients diagnosed with cocaine abuse/dependence (DSM IV criteria), monitoring supervised treatment with oxcarbazepine for 12 weeks. SAMPLE: 30 patients (aged 18 or over) voluntarily undergoing treatment at an Addictive Behaviors Unit (UCA). Patients were selected randomly after providing explicit authorization and informed consent. RESULTS: Abstinence rate increased, reaching 100% of participants that remained in compliance throughout the 12-week period (60% of those who started the treatment). Negative results in the urine test for cocaine detection also increased, reaching 90.9% of those in treatment at week 8. Treatment with oxcarbazepine was seen to produce a statistically significant reduction in craving and impulsivity after 4, 8 and 12 weeks, with respect to baseline measures at the start of treatment. The craving index correlates with reduction in cocaine use. CONCLUSIONS: Oxcarbazepine is effective in reducing impulsivity and craving in relation to cocaine. Thus, we recommend high initial doses of oxcarbazepine in patients with high impulsivity prior to treatment.