Study of Brain Stimulation Effects on Pain Perception and Decision-Making in Adults Aged 18 to 55

What this Trial Is About

Researchers are studying the effects of transcranial direct current stimulation tDCS applied to the left primary motor cortex M1 on thermal pain perception, pain-related decision making, and placebo effects. This randomized, double-blind crossover study involves up to 50 adult participants who undergo four sessions one initial pain calibration and three experimental sessions with anodal, cathodal, or sham tDCS. The study aims to understand how different tDCS conditions influence pain ratings and altruistic behavior during social decision-making tasks. Participants complete an initial pain calibration session to determine their individual pain and tolerance thresholds using controlled heat stimuli on the forearm. Following calibration, participants attend three full study sessions where they receive one of three tDCS interventionsanodal, cathodal, or shameach lasting 20 minutes with a 2 mA current applied via electrodes placed on the scalp. Each session includes pain testing before and after tDCS, a pain-monetary decision-making task, and social placebo pain tests, all conducted inside an MRI scanner. During the study sessions, participants engage in multiple pain trials at their unique temperature thresholds and complete decision-making tasks involving offers of pain and monetary rewards for themselves or others. Researchers measure pain perception using a visual analogue scale shortly after each stimulus and assess decision-making and placebo responses. The sessions are spaced at least five days apart, and participants complete questionnaires about sensations induced by tDCS. The total participation period varies, with assessments occurring during each of the four sessions.

Transcranial Direct Current Stimulation and Modulation of Affect and Pain