Joshua Burk

Research Interests

My general area of research interest is the neural basis of attention, learning, and memory. We have several current lines of research related to these topics:

1. Role of the cholinergic system in attention: Considerable research has demonstrated that the basal forebrain cholinergic system is critical for normal attentional processing. Our recent work (McQuail & Burk, 2006) suggests that cholinergic muscarinic receptors, particularly the muscarinic M1 receptor, are important for mediating the effects of the cortical acetylcholine on attention (Burk & Robinson, 2010). Moreover, we have begun to elucidate the attentional demands that are necessary for demonstrating attentional deficits following loss of basal forebrain corticopetal cholinergic neurons (Burk, Lowder, Altemose, 2008). Our current work in this area involves assessing the role of acetylcholine when attentional demands are varied. I am collaborating with Dr. Greg Smith to develop computational models to predict drug-induced changes in performance in attention-demanding tasks. I am also collaborating with Dr. Paul Kieffaber to measure electrical brain activity during attention-demanding task performance.

2. Role of orexins in attention: In collaboration with Dr. Jim Fadel at the University of South Carolina Medical School, we are testing the role of the orexin system in attention. The orexinergic system originates within the hypothalamus and projects to multiple brain regions, including onto basal forebrain corticopetal cholinergic neurons. Our work has explored the role of the orexin projection to the basal forebrain in attentional processing (Fadel & Burk, 2010). We reported that blockade of orexin-1 receptors with SB-334867, either systemically or via direct infusions into the basal forebrain, disrupts attentional performance (Boschen, Fadel, Burk, 2009).

3. Role of the cholinergic system in decision-making. There is evidence that disruptions of attention can result in more impulsive decisions, such as those decisions measured by delay discounting paradigms. These delay discounting paradigms typically involve choosing an immediate, smaller reward compared with a delayed, larger reward. We are in the process of developing a novel task for assessing delay discounting in rats and plan to explore the role of the cholinergic system in delay discounting. Our long-term goals are to more fully explore whether the cholinergic system interacts with other neurotransmitter systems (e.g., dopamine) typically thought to mediate behavior in delay discounting paradigms.

4. Effects of adolescent nicotine exposure on learning and memory. As part of a collaboration with Dr. Robert Barnet and Dr. Pamela Hunt, we are testing the consequences of adolescent nicotine exposure on learning during adulthood. Previous research has suggested that adolescent nicotine exposure can have long-term effects on several neural markers within the hippocampus. However, the behavioral consequences of these brain changes remain unknown. In these experiments, we are typically assessing nicotine-induced changes in performance of hippocampus-dependent tasks. We have recently reported that adolescent nicotine exposure can produce deficits in context conditioning assessed during adulthood (Spaeth et al., 2010).

Educational Background

B. S. Psychology (Biological Emphasis)  University of California, Davis

M.A. Experimental Psychology  University of New Hampshire

M.S.T. College Teaching  University of New Hampshire

Ph.D., Experimental Psychology  University of New Hampshire

Selected Publications

Boschen KE, Fadel JR, Burk JA (2009) Systemic and intrabasalis administration of the orexin-1 receptor antagonist, SB-334867, disrupts attentional performance in rats. Psychopharmacology, 206, 205-213. Fadel J, Burk JA (2010) Orexin/hypocretin modulation of the basal forebrain cholinergic system: role in attention. Brain Research, 1314, 112-123. (Special issue on “Neuropeptides in Stress and Addiction”). Burk JA, Robinson AM (2010) Muscarinic M1 receptors, protein kinase C and attention: targets for treating Alzheimer’s disease and schizophrenia. Handbook of Drug Targeting and Monitoring (eds. Andreev B, Egorov V). Nova Science Publishers, Hauppauge, NY, pp. 113-129.

Spaeth AM, Barnet RC, Hunt PS, Burk JA (2010) Adolescent nicotine exposure disrupts context conditioning in adulthood in rats. Pharmacology, Biochemistry and Behavior, 96, 501-506.

 

Robinson AM, Mangini DF, Burk JA (in press) Task demands dissociate the effects of muscarinic M1 receptor blockade and PKC inhibition on attentional performance in rats. Journal of Psychopharmacology.

Barnet RC, Hunt PS, Burk JA (in press) Cognitive consequences of adolescent and adult nicotine exposure: utility of animal models. Nicotine Addiction: Prevention, Health Effects and Treatment Options (ed. Di Giovanni G). Nova Science Publishers, Hauppauge, NY.

Courses Taught

• Psychopharmacology
• Research in Physiological Psychology
• Cognitive Neuroscience
• Introduction to Psychology as a Natural Science
• Graduate Proseminar in Behavioral Neuroscience
• Elementary Statistics
• Physiological Psychology
• Graduate Professional Development Seminar