Studying Nicotine Addiction With Transcranial Magnetic Stimulation

* INCLUSION CRITERIA: 1. Males and females 18 - 55 years of age 2. Able to give valid informed consent 3. Right-handed 4. If the subject is female, of childbearing potential, and sexually active, she agrees to use a medically acceptable contraception, and not become pregnant for the duration of the study. A woman is considered of childbearing potential unless post-menopausal or surgically sterilized. Female patients of childbearing potential who are or who anticipate the possibility of becoming sexually active with a male partner must use either: (1) contraceptive pill or intrauterine device (IUD) or depot hormonal preparation (ring, injection implant); and/or (2) a barrier method of contraception such as diaphragm, sponge with spermicide, or condom. Women who are not sexually active do not have to agree to use one of the acceptable contraception methods. Contraceptive measures will be reviewed with female subjects at each visit prior to the TMS session. EXCLUSION CRITERIA:\<TAB\> 1. Personal or first-degree family history of any clinically defined neurological disorder, including organic brain disease, epilepsy, stroke, brain lesions, multiple sclerosis, previous neurosurgery, or personal history of head trauma that resulted in loss of consciousness. 2. Cardiac pacemakers, neural stimulators, implantable defibrillator, implanted medication pumps, intracardiac lines, or acute, unstable cardiac disease, with intracranial implants (e.g. aneurysm clips, shunts, stimulators, cochlear implants, or electrodes) or any other metal object within or near the head that cannot be safely removed. 3. Current use, or use in the past 4 weeks of any investigational drug or of any medications with psychotropic, anti or pro-convulsive action 4. Increased intracranial pressure (lowers seizure threshold) 5. Lifetime history of major depressive disorder, schizophrenia, bipolar disorder, mania, or hypomania or current substance abuse or dependence or past dependence by DSM IV criteria, or urine toxicology positive for any illicit substance. 6. History of myocardial infarction, angina, congestive heart failure, cardiomyopathy, stroke or transient ischemic attack, or any heart condition currently under medical care. 7. Pregnant or nursing women or women with reproductive potential who are sexually active and not using an acceptable form of contraception. 8. Any history of seizure