Modulation of Behavioral Inhibition in Attention Deficit Hyperactivity Disorder

Inclusion Criteria: * Clinical diagnosis of ADHD * Parent informed consent and child assent Exclusion Criteria: * Intracranial pathology from a known genetic disorder (e.g., Neurofibromatosis Type 1 (NF1), tuberous sclerosis) or from acquired neurologic disease (e.g. stroke, tumor), cerebral palsy, history of severe head injury, or significant dysmorphology * History of fainting spells of unknown or undetermined etiology that might constitute seizures * History of seizures, diagnosis of epilepsy, or immediate (1st degree relative) family history epilepsy * Chronic (particularly) uncontrolled medical conditions that may cause a medical emergency in case of a provoked seizure (cardiac malformation, cardiac dysrhythmia, asthma, etc.) * History of head injury resulting in prolonged loss of consciousness * Substance abuse or dependence within the past six months * Chronic treatment with prescription medications that decrease cortical seizure threshold that the patient is unable to withhold from taking during study visits * Damaged skin on the scalp (i.e., skin with ingrown hairs, acne, razor nicks, wounds that have not healed, recent scar tissue, broken skin, etc.)