Subjects

Fifteen male subjects aged 19–34 years (mean age ± standard deviation [SD] 25.2 ± 4.62 years) were recruited to the study from a local research volunteer database. One subject only was not able to complete the TMS‐EEG recording after the intake of lamotrigine; therefore, the total number of subjects for this condition is fourteen. Female participants were excluded due to evidence of menstrual cycle–related effects on cortical excitability, which could introduce a confound.14 All the subject were right‐handed according to the Edinburgh Handedness Inventory (laterality score ≥ 75%).15 Before the experiment, subjects underwent a physical examination and checked for any contraindications to TMS. Exclusion criteria included the use of central nervous system (CNS) active drug, abuse of any kind of drugs (nicotine/alcohol included), contraindications to the study medications (levetiracetam/lamotrigine) and a history of psychiatric or neurologic disease. The experimental protocol was approved by King's College London Research Ethics Committee, and all the participants gave their written informed consent before the experiment.