Ricerc@Sapienza

The ability to inhibit an inappropriate response and to flexibly adjust to a changing environment is a key factor for efficient adaptation and survival. Inhibitory control is recognized as the core underlying function of a) the ability to suppress interference from an irrelevant task during rapid task switching (cognitive-behavioral flexibility); b) the ability to inhibit unwanted emotional thoughts (cognitive-emotional flexibility); and c) the ability of the vagus nerve to inhibit sympathetic arousal (physiological flexibility). Whereas existing studies separately investigated each of these factors, to date there is lack of knowledge on their reciprocal interplay. Also, most research in this field is correlational, precluding inferences on the direction of effects. We aim to fill this gap, by investigating whether the experimental manipulation of inhibitory control via non-invasive brain stimulation techniques has effects on cognitive, behavioral, and emotional inflexibility. We plan to do so by using transcranial direct current stimulation (tDCS) to enhance excitability of the most widely recognized source of inhibitory control, the dorsolateral prefrontal cortex (dlPFC). The hypothesis is that tDCS over dlPFC will boost inhibitory control, and this will in turn enhance flexibility at all the examined levels, as indexed by post-stimulation reduced reaction times during task switching, increased heart rate variability, and decreased ruminative thinking outside the laboratory (via ecological momentary assessment) compared to pre-stimulation and sham conditions. We expect these effects to be mediated by individual differences in emotion regulation capacity. This proposal integrates cognitive and experimental psychology with affective and autonomic neuroscience to advance our understanding of the interplay between neurobiological, emotional, and cognitive factors during maladaptive ruminative thinking, potentially yielding to more effective treatment strategies.