Our laboratory has had a major focus on understanding the role of central nervous system (CNS) nicotinic cholinergic receptors in normal and abnormal human cognition for over 15 years. Nicotinic receptors are ligand-gated ion channels that occur on the surface of neurons (nerve cells) in the brain and serve to modulate neuronal transmission. Nicotinic receptors bind the naturally occurring neurotransmitter acetylcholine and of course nicotine. Research from this laboratory and others has shown that nicotinic receptors appear to be important in regulating learning and memory, anxiety, and motor performance.
Our research has investigated the role of nicotinic receptor functioning in learning and memory both in normal individuals and those with neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. We have also tested the effects of novel nicotinic drugs in humans, designed to produce the positive effects of nicotinic stimulation without some of the liabilities of nicotine itself.
Current research focuses on therapeutic drug development for early memory loss and the importance of nicotinic systems in the cognitive disorder associated with Attention-Deficit/Hyperactivity Disorder (ADHD).
Faculty and staff associated with these projects include:
Studies of Nicotinic Stimulation in Attention-Deficit/Hyperactivity Disorder (ADHD)
Adolescents who suffer from Attention-Deficit/Hyperactivity Disorder (ADHD) become cigarette smokers and tobacco users at twice the rate of non-ADHD adolescents. This high rate of use continues into adulthood. The reasons for this vulnerability of ADHD adolescents to use tobacco at a high rate are poorly understood.
One possible reason is that nicotine, the psychoactive component of tobacco, may produce positive effects on attentional performance in ADHD adolescents. ADHD produces specific attentional difficulties which are partially ameliorated by medications that enhance dopaminergic functioning in the brain. Extensive studies of nicotine over several decades from our laboratory and others have demonstrated that nicotine has significant attentional and cognitive-enhancing effects even in clinical populations with significant neuropsychiatric disorders. It is therefore possible that tobacco use in adolescents serves as a form of self-selected medication to improve some of the cognitive difficulties associated with ADHD.
We are examining whether nicotine, the psychoactive constituent of tobacco, may have positive effects on cognitive and motor processes involving attention that appear to be impaired in many adolescents and young adults with ADHD. The primary aim of these studies is to examine the effects of acute nicotinic stimulation on a measure of behavioral inhibition, decision-making, and motor performance in adolescents and young adults with ADHD. These results should provide significant information as to some of the reasons for the vulnerability of the ADHD population to high rates of tobacco use, and may help in the future development of better and safer alternative treatments for ADHD.
We are currently conducting:
The ADHD fMRI study: This study will collect preliminary data on cognitive functioning (attention, memory and decision-making) during functional magnetic resonance imaging (fMRI) in young adults (18-25) with ADHD. fMRI is a 3-dimensional picture of the brain using magnetic waves. We will ask participants to perform various cognitive tasks while in an fMRI machine to examine what areas of the brain are activated by these tasks. This will be a one-visit study (about 2 hours) conducted at the UVM Functional Brain Imaging Facility at Fletcher Allen Health Care (main hospital). Monetary compensation will be provided to participants. For information on participating in this study, contact Christina Conrath, Research Assistant, at (802) 847-5444 or via email at Christina.conrath@vtmednet.org
The Adult ADHD study: Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most common childhood psychological disorders. While ADHD first appears in childhood the symptoms persist into adolescence and adulthood for up to 80% of people who are diagnosed as children. The most commonly prescribed medications to treat ADHD are the psychostimulants (such as Ritalin). These medications are not effective for all people with ADHD and some people have side effects to the medicines. We are investigating the effectiveness of a new investigational medication for the treatment of adult ADHD. This medication works differently from medicines which are FDA approved for ADHD and may help people who decide not to take other medications. This study is sponsored by Targacept inc.
We are seeking men and women between the ages of 18-65 with ADHD, who are non-smokers. Participants will receive free physical and cognitive screening, study medication, and compensation will also be provided.
Impulsivity is an important factor related to cigarette smoking in women. Impulsivity may be one reason why women begin smoking and have trouble quitting smoking. Our research has shown that nicotine makes non-smokers less impulsive.
One possible reason is that nicotine, the psychoactive component of tobacco, may produce positive effects on attentional performance in ADHD adolescents. ADHD produces specific attentional difficulties which are partially ameliorated by medications that enhance dopaminergic functioning in the brain. Extensive studies of nicotine over several decades from our laboratory and others have demonstrated that nicotine has significant attentional and cognitive-enhancing effects even in clinical populations with significant neuropsychiatric disorders. It is therefore possible that tobacco use in adolescents serves as a form of self-selected medication to improve some of the cognitive difficulties associated with ADHD.
Impulsivity and Smoking in Women: This newly designed study will look at how nicotine affects impulsivity in women smokers and non-smokers. We will use functional magnetic resonance imaging (fMRI) to determine what areas of the brain are involved in nicotine's effect on impulsivity. fMRI is a 3-dimensional picture of the brain using magnetic waves. We will be recruiting smoking and non-smoking women, ages 18 - 25, to participate in this study. This is a four-visit study. Monetary compensation will be provided to those who take part in the study. For information on participating in this study, contact Sally Ross Nolan, M.S. at 802-847-9488 or via email at Sally.Nolan@vtmednet.org.
