No abstract

Transcranial direct current stimulation (tDCS) can enhance cognitive control functions including attention and top-down regulation over negative affect and substance craving in both healthy and clinical populations, including early abstinent (∼1.5 h) smokers. The aim of this study was to assess whether tDCS modulates negative affect, cigarette craving, and attention of overnight abstinent tobacco dependent smokers. In this study, 24 smokers received a real and a sham session of tDCS after overnight abstinence from smoking on two different days. We applied anode to the left dorsolateral prefrontal cortex and cathode to the right supra-orbital area for 20 min with a current of 2.0 mA. We used self-report questionnaires Profile of Mood States (POMS) to assess negative affect and Urge to Smoke (UTS) Scale to assess craving for cigarette smoking, and a computerized visual target identification task to assess attention immediately before and after each tDCS. Smokers reported significantly greater reductions in POMS scores of total mood disturbance and scores of tension–anxiety, depression–dejection, and confusion–bewilderment subscales after real relative to sham tDCS. Furthermore, this reduction in negative affect positively correlated with the level of nicotine dependence as assessed by Fagerström scale. However, reductions in cigarette craving after real vs. sham tDCS did not differ, nor were there differences in reaction time or hit rate change on the visual task. Smokers did not report significant side effects of tDCS. This study demonstrates the safety of tDCS and its promising effect in ameliorating negative affect in overnight abstinent smokers. Its efficacy in treating tobacco dependence deserves further investigation.

The behavioral inhibition system (BIS) and behavioral activation system (BAS) are hypothesized to underlie motivated behavior, relate to hippocampal and amygdalar function, and link to pathological gambling (PG). Prior studies have not investigated hippocampal and amygdalar volumes in PG and their relationships to BIS/BAS measures. Structural MRI scans and BIS/BAS and other clinical measures were obtained from 32 PG individuals and 47 healthy comparison (HC) individuals. Volumetric measures of the hippocampus and amygdala were assessed using FreeSurfer and related to BIS/BAS measures. PG relative to HC individuals demonstrated diminished volume in the left hippocampus and right amygdala and higher BIS and BAS scores. BIS scores were positively correlated with left hippocampal and left amygdalar volumes in PG individuals. The findings of relatively diminished hippocampal and amygdalar volumes in PG individuals resonate with findings from substance-dependent groups. Relationships between amygdalar and hippocampal volumes and BIS measures in PG suggest that individual differences in these structures may contribute to avoidance behaviors in PG.