Comparison of Neural Correlates of Reactive Inhibition in Cocaine, Heroin, and Polydrug Users through a Contextual Go/No-Go Task Using Event-Related Potentials.

Recent global data indicates a worldwide increase in polydrug use associated with a shift from recreational to productive habits of consumption. Such non-responsible abuse of substances (alcohol, cocaine, heroin, etc.) is likely to lead to addictive disorders that are characterized by various neuropsychopharmacological effects. A main cognitive function involved in the onset and long-term maintenance of addiction is reactive inhibition, i.e., the ability to withhold a prepotent motor dominant response. In the present study, 63 (poly)drug user patients who were undergoing a detoxification program, in addition to 19 healthy controls matched for gender, age, and education, were subjected to a "contextual Go/No-Go task" with concomitant electroencephalography. Stimuli were superimposed on three contextual backgrounds: control (black screen), drug-unrelated (neutral pictures), or drug-related (pictures related to drug consumption). Of these patients, 23 were cocaine users (CU), 21 were heroin users (HU), and 19 were polydrug users (PDU). The main results showed that (1) at the behavioral level, more commission errors occurred with the PDU patients compared to the healthy controls; (2) at the neurophysiological level, specific alterations were found on classical event-related potentials that index reactive inhibition. Indeed, the higher rate of errors in the PDU group was subtended by both reduced amplitude and latency on the ∆N2 component and increased ∆P3 latency compared to controls. These data clearly suggest a more deleterious impact of polydrug use on inhibitory functions. In addition, our results provide evidence of reduced ERN amplitude in cocaine users, suggesting that impaired performance monitoring and error-processing may support impaired awareness, thereby preventing these patients from changing their behaviors.

Transcranial Direct Current Stimulation Combined With Cognitive Training Induces Response Inhibition Facilitation Through Distinct Neural Responses According to the Stimulation Site: A Follow-up Event-Related Potentials Study.

OBJECTIVE: We investigated whether the mid-term impact (1 week posttraining) of a "combined cognitive rehabilitation (CRP)/transcranial direct current stimulation (tDCS) program" on the performance of a Go/No-go task was enhanced compared with isolated CRP and whether it varied according to the stimulation site (right inferior frontal gyrus [rIFG] vs right dorsolateral prefrontal cortex [rDLPFC]). METHODS: A total of 150 healthy participants were assigned to (1) an Inhibition Training (IT) group, (2) a group receiving active tDCS over the rIFG in combination with IT (IT + IF), (3) a group receiving active tDCS over the rDLPFC in combination with IT (IT + DL), (4) a group receiving IT with sham tDCS (ITsham), and (5) a No-Training (NT) group to control for test-retest effects. Each group undertook 3 sessions of a Go/No-go task concomitant with the recording of event-related potentials (T0, before training; T1, at the end of a 4-day training session [20 minutes each day]; T2, 1 week after T1). RESULTS: With the exception of the NT participants, all the groups exhibited improved performances at T2. The IT + DL group exhibited the best improvement profile, indexed by faster response times (RTs) (T0 > T1 = T2), with a reduced rate of errors at the posttraining sessions compared with both T0 and T1. This "inhibitory learning effect" was neurophysiologically indexed by shorter No-go N2d latencies and enhanced No-go P3d amplitudes. CONCLUSION: CRP combined with active tDCS over the rDLPFC appears to be optimal for boosting long-term (one week) inhibitory skills as it induced specific and robust neural changes.

Transcranial direct current stimulation combined with alcohol cue inhibitory control training reduces the risk of early alcohol relapse: A randomized placebo-controlled clinical trial.

BACKGROUND: Approximately half of all people with alcohol use disorder (AUD) relapse into alcohol reuse in the next few weeks after a withdrawal treatment. Brain stimulation and cognitive training represent recent forms of complementary interventions in the context of AUD. OBJECTIVE: To evaluate the clinical efficacy of five sessions of 2 mA bilateral transcranial direct current stimulation (tDCS) for 20 min over the dorsolateral prefrontal cortex (DLPFC) (left cathodal/right anodal) combined with alcohol cue inhibitory control training (ICT) as part of rehabilitation. The secondary outcomes were executive functioning (e.g. response inhibition) and craving intensity, two mechanisms strongly related to abstinence. METHODS: A randomized clinical trial with patients (n = 125) with severe AUD at a withdrawal treatment unit. Each patient was randomly assigned to one of four conditions, in a 2 [verum vs. sham tDCS] x 2 [alcohol cue vs. neutral ICT] factorial design. The main outcome of treatment was the abstinence rate after two weeks or more (up to one year). RESULTS: Verum tDCS improved the abstinence rate at the 2-week follow-up compared to the sham condition, independently of the training condition (79.7% [95% CI = 69.8-89.6] vs. 60.7% [95% CI = 48.3-73.1]; p = .02). A priori contrasts analyses revealed higher abstinence rates for the verum tDCS associated with alcohol cue ICT (86.1% [31/36; 95% CI = 74.6-97.6]) than for the other three conditions (64% [57/89; 95% CI = 54-74]). These positive clinical effects on abstinence did not persist beyond two weeks after the intervention. Neither the reduction of craving nor the improvement in executive control resulted specifically from prefrontal-tDCS and ICT. CONCLUSIONS: AUD patients who received tDCS applied to DLPFC showed a significantly higher abstinence rate during the weeks following rehabilitation. When combined with alcohol specific ICT, brain stimulation may provide better clinical outcomes. TRIAL REGISTRATION: ClinicalTrials.gov number NCT03447054 https://clinicaltrials.gov/ct2/show/NCT03447054.

Preventing relapse in alcohol disorder with EEG-neurofeedback as a neuromodulation technique: A review and new insights regarding its application.

Alcohol Use Disorder (AUD) has a disconcertingly high relapse rate (70-80% within a year following withdrawal). Preventing relapse or minimizing its extent is hence a challenging goal for long-term successful management of AUD. New perspectives that rely on diverse neuromodulation tools have been developed in this regard as care supports. This paper focuses on electroencephalogram-neurofeedback (EEG-NF), which is a tool that has experienced renewed interest in both clinical and research areas. We review the literature on EEG-based neurofeedback studies investigating the efficacy in AUD and including at least 10 neurofeedback training sessions. As neurofeedback is a form of biofeedback in which a measure of brain activity is provided as feedback in real-time to a subject, the high degree of temporal resolution of the EEG interface supports optimal learning. By offering a wide range of brain oscillation targets (alpha, beta, theta, delta, gamma, and SMR) the EEG-NF procedure increases the scope of possible investigations through a multitude of experimental protocols that can be considered to reinforce or inhibit specific forms of EEG activity associated with AUD-related cognitive impairments. The present review provides an overview of the EEG-NF protocols that have been used in AUD and it highlights the current paucity of robust evidence. Within this framework, this review presents the arguments in favor of the application of EEG-NF as an add-on tool in the management of alcohol disorders to enhance the cognitive abilities required to maintain abstinence more specifically, with a focus on inhibition and attentional skills.

Training Inhibitory Control Induced Robust Neural Changes When Behavior Is Affected: A Follow-up Study Using Cognitive Event-Related Potentials.

Cognitive training results in significant, albeit modest, improvements in specific cognitive functions across a range of mental illnesses. Inhibitory control, defined as the ability to stop the execution of an automatic reaction or a planned motor behavior, is known to be particularly important for the regulation of health behaviors, including addictive behaviors. For example, several studies have indicated that inhibitory training can lead to reduced alcohol consumption or a loss of weight/reduced energy intake. However, the exact neurocognitive mechanisms that underlie such behavioral changes induced by training are still matter of debate. In the present study, we investigated the long-term impact (ie, at 1 week posttraining) of an inhibitory training program (composed of 4 consecutive daily training sessions of 20 minutes each) on the performance of a Go/No-go task. Healthy participants were randomly assigned to 1 of 3 designated groups: (1) an Inhibition Training (IT) group that received training based on a hybrid flanker Go/No-go task; (2) a group that received a noninhibition-based (ie, episodic memory; EM) training; and (3) a No-Training (NT) group to control for test-retest effects. Each group underwent 3 sessions of a Go/No-go task concomitant with the recording of event-related potentials. Our results revealed a specific impact of the Inhibitory Training on the Go/No-go task, indexed by a faster process compared with the other 2 groups. This effect was neurophysiologically indexed by a faster N2 component on the difference NoGo-Go waveform. Importantly, effects at both the behavioral and at the neural level were still readily discernible 1 week posttraining. Thus, our data clearly corroborate the notion that cognitive training is effective, while also indicating that it may persist over time.

Increased Neural Activity in Hazardous Drinkers During High Workload in a Visual Working Memory Task: A Preliminary Assessment Through Event-Related Potentials.

Despite equated behavioral performance levels, hazardous drinkers generally exhibited increased neural activity while performing simple cognitive tasks compared to light drinkers. Here, 49 participants (25 hazardous and 24 light drinkers) participated in an event-related potentials (ERPs) study while performing an n-back working memory task. In the control zero-back (N0) condition, the subjects were required to press a button when the number "2" or "6" was displayed. In the two-back and three-back (N2; N3) conditions, the subjects had to press a button when the displayed number was identical to the number shown two/three trials earlier. To assess for the impact of alcohol consumption on the updating of working memory processes under various cognitive loads, difference waveforms of "N2 minus N0" and "N3 minus N0" were computed by subtracting waveforms in the N0 condition from waveforms in the N2 and N3 conditions, for the light and the hazardous drinkers. Three main ERP components were noted for both groups: a P200/N200 complex, a P300 component, and an N400/P600 activity. The results show that, to perform the task at the same level as the light drinkers, the hazardous drinkers exhibited larger amplitude differences, mainly around the P300 and P600 components. These data may be considered, at the preventive level, as vulnerability factors for developing adult substance use disorders, and they stress the importance, at a clinical level, to consider such working memory processes in the management of alcohol dependence.