Nicotinic Modulation of the Default Network of Resting Brain Function

Completed

Conditions studied: Nicotine Dependence

In brief

Background: \- A brain circuit called the default network is the brain circuit that is active when the brain is at rest; that is, when individuals are not concentrating on specific tasks. Previous research has shown that the default network functions differently in people with schizophrenia and Alzheimer s disease, and may contribute to the problems with memory and concentration that can affect people who have these conditions. Studies have also shown that nicotine affects the default network, but more research is needed on the ways in which nicotinic receptors may change activity in these regions and thereby affect individuals ability to concentrate on specific tasks. Objectives: \- To determine whether and how nicotine and mecamylamine, a drug that blocks nicotinic receptors, affect the default network in nonsmokers in ways that improve thinking and concentration. Eligibility: * Healthy, right-handed volunteers between 21 and 50 years of age. * Volunteers must not have used any kind of tobacco product in the past 2 years. Design: * This study involves an initial screening visit, a training visit, and three testing visits. * Participants will be screened with a medical history and physical examination, as well as blood and urine samples and questions about smoking history. * Participants will have an initial training session to practice the tasks that will be done during magnetic resonance imaging scans at the testing visits. These tasks will test participants concentration and memory. * Participants will have three test sessions with the following combinations of study drugs: (1) a nicotine patch and a placebo capsule, (2) a placebo patch and a capsule of mecamylamine, or (3) a placebo patch and capsule. Different combinations will be given at each visit, and participants will not know which one they receive. * Participants will perform the same concentration and memory tasks at each testing visit, and will provide a blood sample after each visit to determine levels of nicotine and mecamylamine.

Key facts

Study ID

NCT01240616

Run by

National Institute on Drug Abuse (NIDA)

People needed

43

Starts

2010-10-24

Expected to finish

2014-12-24

Last updated by the study team

2018-07-05

Who can join

Age: 21 and older, up to 55. Sex: any. Healthy volunteers: accepted.

You may not qualify if…

• Presence of metal objects in the body, implanted electronic devices, or any other counter indication for MRI.
• Claustrophobia.
• Major psychiatric disorders including mood, anxiety or psychotic disorders.
• Cardiovascular or cerebrovascular disease, such as history of myocardial infarction, heart failure, angina, stroke, severe arrhythmias, or EKG abnormalities as specified under Screening methods .
• Kidney or liver disease.
• Hypertension (resting systolic BP above 140 or diastolic above 85 mm Hg).
• Hypotension (resting systolic BP below 95 or diastolic below 60).
• Use of any prescription or over-the-counter drug other than supplements and birth control.
• History of or current neurological illnesses, such as stroke, seizures, dementia or organic brain syndrome.
• Learning disability, attention deficit disorder, or any other condition that impedes memory and attention.
• Glaucoma, organic pyloric stenosis, uremia or renal insufficiency (see Mecamylamine-related risks).
• Prostatic hypertrophy, bladder neck obstruction or urethral stricture (see Mecamylamine-related risks).
• Left-handed or ambidextrous.
• Pregnant as determined by urine test, or breast-feeding.
• History or current diagnosis of drug or alcohol abuse or dependence.
• IQ < 85 as estimated by the WASI vocabulary subtest.
• Strong disposition to get car sick.

Where it is running

• National Institute on Drug Abuse, Biomedical Research Center (BRC) — Baltimore, Maryland, United States
• University of Maryland at Baltimore/MPRC — Catonsville, Maryland, United States

Full record on ClinicalTrials.gov

Trial information comes from ClinicalTrials.gov and is refreshed daily. TrialsForMe does not provide medical care and does not run the studies it lists.