Inhibitory control refers to the ability to inhibit an action once it has been initiated. Impaired inhibitory control plays a key role in triggering relapse in some pathological states, such as addictions. Therefore, a major challenge of current research is to establish new methods to strengthen inhibitory control in these "high-risk" populations. In this attempt, the right inferior frontal cortex (rIFC), a neural correlate crucial for inhibitory control, was modulated using transcranial direct current stimulation (tDCS). Healthy participants (n = 31) were presented with a "Go/No-go" task, a well-known paradigm to measure inhibitory control. During this task, an event-related potential (ERP) recording (T1; 32 channels) was performed. One subgroup (n = 15) was randomly assigned to a condition with tDCS (anodal electrode was placed on the rIFC and the cathodal on the neck); and the other group (n = 16) to a condition with sham (placebo) tDCS. After one 20- minute neuromodulation session, all participants were confronted again with the same ERP Go/No-go task (T2). To ensure that potential tDCS effects were specific to inhibition, ERPs to a face-detection task were also recorded at T1 and T2 in both subgroups. The rate of commission errors on the Go/No-go task was similar between T1 and T2 in both neuromodulation groups. However, the amplitude of the P3d component, indexing the inhibition function per se, was reduced at T2 as compared with T1. This effect was specific for participants in the tDCS (and not sham) condition for correctly inhibited trials. No difference in the P3 component was observable between both subgroups at T1 and T2 for the face detection task. Overall, the present data indicate that boosting the rIFC specifically enhances inhibitory skills by decreasing the neural activity needed to correctly inhibit a response.

Background: This pilot study explores a therapeutic setting combining transcranial direct current stimulation (tDCS) and mindfulness-based cognitive therapy (MBCT) for patients with drug-resistant depression. tDCS has shown efficacy for depression treatment and improvement could be maintained with the combination with mindfulness, which has shown depression relapse-prevention properties.Methods: Thirty-one treatment-resistant depressed patients have been assigned to our experimental treatment condition [tDCS combined with MBCT (n = 15)] or to a control condition [tDCS combined with relaxation (n = 16)]. Patients have completed both an intensive treatment block (eight consecutive days) and a single remind session 2 weeks after the intensive treatment. Clinical (depression, anxiety, and rumination) and cognitive (general cognitive functioning, mental flexibility, and working memory) symptoms of depression have been assessed through different questionnaires at baseline (t0), after the first block of treatment (t1), and after the remind session (t2).Results: Results seem to indicate a positive impact of both treatment conditions on clinical and cognitive symptoms of depression at t1. However, the treatment condition combining tDCS with mindfulness has been found to better maintain clinical improvements at t2 regarding some clinical [Montgomery–Åsberg Depression Rating Scale (MADRS) and Sadness and Anger Ruminative Inventory (SARI)] and cognitive variables (Digit Span-F and Digit Span-B).Conclusion: Based on the current observations, a multi-disciplinary treatment approach combining tDCS and MBCT might be effective in resistant depressed patients in the long run, even though further clinical research is necessary.

Major depression is a serious disorder of impaired emotion regulation. Emotion hyperactivity leads to excessive negative ruminations that daily hijack the patient’s mental life, impacting their mood. Evidence from past researches suggest that depressive patients present several cognitive impairments in attention and working memory, leading to a more acute selective attention for negative stimuli and a greater accessibility of negative memories. Recently, is has been proposed that impaired inhibitory functioning with regard to emotional information processing might be one of the mechanisms of ruminations linking memory, attention and depression. It seems that inhibition deficit is present at both the input level (i.e., the ability to reduce the interference from emotional distracters) and the higher level (i.e., the ability to direct the attention away from emotional material that has already been processed) of emotional information processing. Event-related potentials (ERP) have widely been used to study inhibition in adults suffering from various psychopathological states. In particular, depressive disorder has been linked to ERPs modulations, at early as well as at latter stages of the information-processing stream, when processing affective material. For instance, deficits in inhibiting negative information have been indexed by changes in the parameters (amplitudes and latencies) of early P2, P1 and N1 components while other ERP studies have shown an ability to differentiate depressed patients from normal controls based upon response inhibition difficulties in go-nogo tasks, indexed by later NoGo P3 differences. In this review, we will focus on results of ERP studies investigating inhibition and its interaction with emotional related cue processing in depressive populations. Implications for future research and theoretical perspectives will be discussed within the framework of current models of depressive disorder, based upon the hypothesis that negative ruminations are at the center of depression processes.