fNIRS Neurofeedback in Highly Impulsive Participants With ROI Regions DLPFC and IFG

The aim of the following study is to investigate which is the best region of interest (ROI) for a functional near-infrared spectroscopy (fNIRS)-based neurofeedback (NF) training for highly-impulsive individuals (and consequently also patients with attention-deficit/hyperactivity disorder, ADHD): the dorsolateral prefrontal cortex (DLPFC) or the inferior frontal gyrus (IFG). Generally, NF trainings aim to improve the neurophysiological as well as cognitive-behavioral deficits observed in many neuropsychiatric disorders and were shown to constitute an effective complementary treatment option for patients with ADHD. Some previous studies used the DLPFC as a ROI for NF training, while others focused on the IFG as the main target region. However, so far, no study has directly compared the effectiveness of NF trainings targeting the DLPFC vs. IFG using the same protocol or the specificity of regulation efforts between these two areas using fNIRS. Therefore, the aim of the current study is to compare the effectiveness of fNIRS-NF using the DLPFC as a ROI with fNIRS-NF using the IFG as a ROI in a randomized controlled study design with highly-impulsive, healthy participants. Furthermore, the investigators aim to test the effect of fNIRS-NF training in the context of stress. Previous studies reported that there is a strong connection between ADHD and stress. However, the effect of fNIRS-NF training for the adaptation to stressful situations is uncertain. To this end, the investigators will assess the brain activity of participants before and after an fNIRS-NF training period during performance of a Go/NoGo task, an n-back task and The Trier Social Stress Test (TSST). It is hypothesized that both trainings will be successful in reducing impulsive behavior; however, in the pre/post testing, specific effects of fNIRS-based NF of the DLPFC are expected on working memory function and of fNIRS-based NF of the IFG on inhibitory control (Go/NoGo task). Correlations between both fu