Christopher M Warren

Dissertation

Event-related potential correlates of catecholinergic neuromodulators norepinephrine and dopamine

Supervisor

Dr. Clay Holroyd

Research interests

As a postdoctoral researcher hosted jointly by the Holroyd lab and the Seaman's lab at UBC, I have spent the last year investigating how the midbrain dopamine system interacts with the anterior cingulate cortex (ACC) through single-cell recordings from the ACC of awake, behaving animals.  The midbrain dopamine system is a collection of dopamine-releasing nuclei and pathways implicated in reward processing and reinforcement learning, theorized to impact decision making in the ACC. To date the investigation has involved searching for and identifying the impact of dopamine signals in the ACC. The project will culminate in using optogenetics to turn the dopamine reward pathways on and off to allow cause-and-effect analysis of the interaction of the midbrain dopamine system and the ACC.

Before beginning my postdoctoral research, I spent the last five years in the Masson lab and the Holroyd lab, investigating the locus coeruleus-norepinephrine system and its role in attention and cognitive control. The locus coeruleus is a cluster of neurons in the brainstem that provide norepinephrine to most of the brain. An interesting property of norepinephrine is that it enhances the responsivity of neurons in the neocortex, which is theorized to increase the signal-to-noise ratio of signal processing in the brain. This system may serve as a processing enhancement utility that can be recruited in response to motivationally-salient and/or conflict-inducing events. To date I have investigated this system by inferring its behaviour from cognitive performance on specific tasks, and from and electrophysiological signature of brain activity that may be a manifestation of LC-NE system activity. I have also examined these theorized manifestations of LC-NE activity in psychopathic inmates, who are thought to have a peculiar attentional deficit.

In October, 2012, I will begin a second postdoctoral position, working with Sander Nieuwenhuis in his lab in Leiden, The Netherlands. This work will involve further research into the activity of the locus coeruleus-norepinephrine system, primarily using fMRI technique but also pharmacological manipulation and event-related potential technique. We will be using many exciting and cutting edge analysis techniques with our fMRI data, including brainstem imaging, connectivity analysis, and  multivariate pattern analysis. Dr. Nieuwenhuis is one of the world's foremost experts on the cognitive and computation neuroscience of the locus coeruleus-norepinephrine system.

Represtative publications

Warren, C. M., & Holroyd, C. B. (2012).The Impact of Deliberative Strategy Dissociates ERP Components Related to Conflict Processing vs. Reinforcement Learning. Frontiers in Neuroscience, 6(43).doi: 10.3389/fnins.2012.00043.

Wolf, R. C., Carpenter, R. W., Warren, C. M., Zeier, J. D., Baskin-Sommers, A. R., & Newman, J. P. (2011). Reduced Susceptibility to the Attentional Blink in Psychopathic Offenders: Implications for the Attentional Bottleneck hypothesis. Neuropsychology, no pagination specified. doi: 10.1037/a00260001.

Warren, C. M., Tanaka, J. W., & Holroyd, C. B. (2011). What Can Topology Changes in the Oddball N2 Reveal about Underlying Processes? NeuroReport, 22(17): 870-874.

Awards

• 2011 - Vickery Graduate Award: $750.00 
• 2010 - Quality Move Merit Award: $2,000 
• 2009-2010 - Norma M. Wilson Award: $7,000  
• 2008-2011 - NSERC D-CGS:  $105,000  
• 2008-2010 - MSFHR Research Trainee: $14,000 stipend top-up, $10,000 research and travel     
• 2007-2008 - NSERC M-CGS:  $17,500 
• 2007-2008 - Presidents Research Scholarship:  $4,000
• 2007 - CSBBCS Donald Hebb Graduate Student Award for best poster: $500
• 2006-2007 - Uvic Fellowship: $13,500
• 2006 - CPA Award of Academic Excellence
• 2004-2005 - University of Ottawa Merit Scholarship: $1,000
• 2002-2006 - Deans Honour List, University of Ottawa and University of Guelph