Dorsolateral Prefrontal Cortex Activity and Neuromodulation in Crack-Cocaine Dependents during Early Abstinence

Abstract

Rationale: It is broadly known that addicted subjects have frontal dysfunction which is translated into: 1) low frontal activity in areas related to executive functions involved in the control over drug use; and 2) high frontal activity in areas related to incentive salience involved in the craving for drug use. Method: Electrical activity was correlated with days of abstinence and then sham-controlled session of transcranial direct current stimulation (tDCS) was performed in crack-cocaine users up to one month of abstinence. They were randomly divided to receive left cathodal/right anodal tDCS (20 min, 2 mA, 35 cm 2) or sham procedure over the dorsolateral prefrontal cortex (DLPFC). Results: Absolute values from low-resolution brain electromagnetic tomography (LORETA) indicated that the activity in both left and right DLPFC increases progressively from the tenth day of abstinence. The left cathodal/right anodal tDCS prevented the increase of the activity in the left DLPFC facing crack-cocaine cue presentation in the visual P3 time window (350-600 ms). Spontaneous changes in the right DLPFC were not affected by tDCS. Conclusion: Prefrontal tDCS seems to modulate the DLPFC response to drug cue exposure in this preliminary study with crack-cocaine users suggesting this technique as an effective tool in reducing craving during early abstinence.