Overview
This study will assess the long-lasting effects of personalized theta burst stimulation (TBS), a repetitive form of transcranial magnetic stimulation (TMS), over the left prefrontal cortex on the approach/avoidance behavior. TBS will be personalized based on the prefrontal theta rhythm captured with electroencephalography (EEG). The main questions it aims to answer are: 1. does a single session of personalized TBS synchronized with the individual theta rhythm over the left prefrontal cortex results in the outlasting changes in the individual behavior? 2. Does TBS results in the brain rhythms' changes as measured using resting-state EEG?
Description
This is a double-blinded, counterbalanced crossover study in healthy adults. Volunteers will participate in four TBS-EEG sessions. In each, the investigators will first conduct the approach/avoidance test with EEG. The TBS pulse intensity will be defined according to the resting motor threshold (rMT). After the approach/avoidance test, one of four conditions will be delivered in a randomized order: 1. Verum: personalized closed-loop TBS-EEG stimulation over the left DLPFC at a suprathreshold pulse intensity (up to 120% rMT); 2. Spatial control: personalized TBS stimulation over the functionally irrelevant postcentral gyrus, 3. Temporal control: conventional (non-personalized) TBS with random parameters but the same number of pulses over conventionally defined DLPFC. 4. Dose control: similar to verum but at a subthreshold pulse intensity (up to 80% rMT). At every session, 1,800 pulses will be applied. Following the stimulation, the participant will repeat the approach/avoidance test with EEG.
Eligibility
Inclusion Criteria:
- Participants must be legal adults between the ages of 18 to 65;
- Able and willing to complete study procedures and tasks.
Exclusion Criteria:
- History or evidence of chronic neurological or mental disorder;
- Chronic condition that requires pharmacological treatment over the course of study participation;
- Pregnancy or breastfeeding;
- History or evidence of alcohol or drug addiction;
- Contraindications for transcranial magnetic stimulation (history of seizures, metallic or electric implant in the head/neck area);
- Contraindications for magnetic resonance imaging at 3 Tesla (non-compatible implants, metallic foreign bodies, insulin pump, pacemaker).