OHSU

Jonathan Raybuck

Postdoctoral Fellow

Email 

jdraybuck@gmail.com   

Major Areas of Research 

Neurobiology of learning and memory

Education 

  • BA, Psychology, Edinboro University of Pennsylvania, Edinboro, PA (2004) 
  • PhD, Experimental Psychology, Temple University, Philadelphia, PA (2009)   

Research Interests             

My pre-doctoral work focused on the role of nicotinic acetylcholinergic receptors (nAChRs) in the acquisition and retrieval of trace, delay and contextual fear conditioning, as well as the effects of acute, chronic, and withdrawal from chronic nicotine on trace fear conditioning.  From this work I was able to demonstrate (1) that systemic acute nicotine administration enhances trace conditioning, (2) that with chronic exposure to the drug animals develop tolerance to these effects, (3) that withdrawal of chronic treatment produces deficits in acquisition of trace conditioning, and (4) that these withdrawal effects depend upon Beta-2 subunit-containing high-affinity nicotinic acetylcholinergic receptors.  This work can be interpreted in terms of Opponent-process Theory, which describes initial drug effects as the A-process (euphoric in the case of drugs of abuse) and predicts that over time a B-process (Opponent-process) develops to counter the A-process and maintain homeostasis.  In the case of nicotine's effects on cognition it appears that beta-2 subunits play a critical role in the A-process, but the mechanisms underlying the Opponent-process are as yet unknown.  Subsequently, I demonstrated that the effects of acute local nicotine or nicotinic antagonist infusion into hippocampal and prefrontal cortical brain regions have varied effects on acquisition and retrieval trace, contextual and delay fear conditioning.  These findings suggest that the involvement of nAChRs in learning and memory is dependent on the phase of learning and the brain region being investigated, and that the effects of systemic nicotine likely result from a complex interaction of different effects in multiple brain regions. 

My current work focuses on further investigation of the substrates of trace fear conditioning, as well as examination of the neural substrates that support retrieval and extinction of place conditioning.   

Manuscripts   

Raybuck, JD, Gould TJ.  (in prep).  Local Effects of Nicotine and Nicotinic Antagonists on Trace, Contextual, and Delay Fear Conditioning:  Nicotinic Acetylcholinergic Contributions in the Medial Prefrontal Cortex and Hippocampus to Trace Fear Conditioning.    

Raybuck, JD, Gould TJ.  (2009).  Nicotine Withdrawal-Induced Deficits in Trace Fear Conditioning in C57BL/6 Mice: A Role for High-Affinity ß2 Subunit-Containing Nicotinic Acetylcholine Receptors.  European Journal of Neuroscience.   

Raybuck, JD, Portugal, GS, Gould TJ.  (2008).  Varenicline Ameliorates Nicotine Withdrawal-Induced Learning Deficits in C57BL/6 Mice. Behavioral Neuroscience. 122, 1166-71.   Raybuck, JD, Gould, TJ. (2007) Extra-Cellular Regulated Kinase 1/2 Involvement in the Enhancement of Contextual Fear Conditioning by Nicotine. Behavioral Neuroscience. 121(5), 1119-24. 

Raybuck, JD, Gould, TJ. (2007) Extra-Cellular Regulated Kinase 1/2 Involvement in the Enhancement of Contextual Fear Conditioning by Nicotine. Behavioral Neuroscience. 121(5), 1119-24.