Matthew Palmatier , Ph.D.

I received my Ph.D. in Experimental Psychology from the University of Nebraska in 2004 under the supervision of Dr. Rick A. Bevins. My dissertation examined how drug states can function as discriminative stimuli in Pavlovian conditioning tasks. From 2004 to 2007, I was a postdoctoral scholar in the Departments of Psychology and Neuroscience at the University of Pittsburgh under the supervision of Dr. Anthony R. Caggiula & Dr. Alan F. Sved. My postdoctoral research involved the study of nicotine reinforcement in rat models (self-administration) and evaluation of pharmacotherapies for tobacco cessation.

My current research examines the biobehavioral bases of addictions using multiple rodent models. The primary model in my laboratory is drug self-administration; we use this model to evaluate the reinforcing properties of nicotine, caffeine, and other licit and illicit abused drugs. We also use this model to evaluate how drug effects interact with the effects of non-drug reinforcers. For example, a person who is experimenting with addictive drugs is influenced by many non-drug factors (peer groups, taste of alcohol, etc.) without prior knowledge that the subjective drug effect itself is something good (rewarding/reinforcing). As a result, the non-drug influences tend to guide individuals toward or away from experimentation. Interestingly stimulant drugs tend increase the incentive value of these non-drug stimuli, which can promote future drug taking and may encourage long-term exposure and taking drugs in excess.

A second model employed in my laboratory is Place Conditioning. Using this model, we are able to ask rodent subjects if their experience in one discrete environment (paired with drug effect) was more pleasurable or aversive than their experience in a separate and physically distinct environment (paired with placebo). On a test in which subjects are given a choice between the two environments, we can evaluate whether and to what extent a drug treatment was rewarding or aversive. Notably, drugs that we think of as mild intoxicants but highly addictive (nicotine, caffeine, etc.), have modest effects on where rats spend their time. In fact, rats often report that their experience with nicotine is negative by spending more time in a placebo-paired environment. The discordance between abuse liability (nicotine is considered highly addictive) and rewarding/reinforcing effects of a drug is counterintuitive, and may depend on secondary or mood enhancing properties of the drugs. My laboratory evaluates these effects by evaluating responsiveness to typical rewards. Do subject’s experiences with drugs change as a qualitative function of the stimuli in their environment?

Student Involvement

Undergraduate and graduate students working in my laboratory are involved in all aspects of the research process. Students can expect to be working on their own projects in which they will help to develop the rationale for studies, design and implement the procedures, collect and analyze the data, and report their findings in conference presentations or peer-reviewed publications. Dr. Palmatier can be contacted by email (mattyp@ksu.edu) or phone (785-532-0613) by students interested in more information about opportunities in his lab.

Representative Publications (*indicates student co-author)

• Palmatier MI, Liu X, *Matteson GL, Donny EC, Caggiula AR, Sved AF (2007). Conditioned reinforcement in rats established with self-administered nicotine and enhanced by noncontingent nicotine. Psychopharmacology, online first, DOI: 10.1007/s00213-007-0897-6.

• Palmatier MI, Liu X, Caggiula AR, Donny EC, Booth S, Gharib M, Craven L, Sved AF (2007). The role of nicotinic acetylcholine receptors in the primary reinforcing and reinforcement enhancing effects of nicotine. Neuropsychopharmacology, 32: 1098-1108.

• Palmatier MI, Bevins RA (2007). Drug state facilitation of goal-seeking is resistant to extinction. Behavioural Brain Research, 176: 292-301.

• Palmatier MI, *Matteson GL, *Black JJ, Liu X, Caggiula AR, Sved AF (2007). The reinforcement enhancing effects of nicotine depend on the incentive value of non-drug reinforcers and increase with repeated drug injections. Drug and Alcohol Dependence, 89: 52-59.

• Palmatier MI, Bevins RA (submitted). Drug states transfer facilitative control of goal seeking to novel situations. Behavioural Brain Research.

• Palmatier MI, Liu X, Caggiula AR, Donny ED, Booth S, Gharib M, Craven L, Sved AF (submitted). Metabotropic glutamate 5 receptors (mGluR5) mediate the primary reinforcing, but not the reinforcement enhancing effects of nicotine.

• Palmatier MI, *Bak KM, Caggiula AR, Liu X, Donny EC, Sved AF (in preparation). What is ‘sensory reinforcement’ and why is it important to addictions research?

• Palmatier MI, *Mays KL, *Bak KM, *Levin ME, Caggiula AR, Liu X, Donny EC, Sved AF (in preparation). Nicotine and bupropion have a similar effect on responding for reinforcing non-drug stimuli.