B.Sc. Calgary, Ph.D. Memorial Associate Professor

Office: SN1053

Phone: (709) 864-2323

Email: sgwalling@mun.ca

Affiliations: Behavioural Neuroscience

Research Interests

My research interests are focused largely on the function of the primary norepinephrine containing nucleus, the locus coeruleus (LC), located in mammalian brainstem. Although this nucleus is small, it has the capacity to modulate brain plasticity, memory, and complex cognitive processes. Recent evidence also strongly suggests that the pathological changes underlying Alzheimer’s disease are first initiated by abnormal LC function, which may develop as early as young adulthood. Our work examines LC modulation of temporal lobe (entorhinal cortex and hippocampus) function, and additionally we are working with a small team of MUN researchers to develop a novel LC-dependent rodent model of Alzheimer’s disease. Examples of research techniques used in the lab include electrophysiology, immunohistochemistry, viral vector technology, optogenetics, behaviour, and electrochemistry.

Additional research interests (keywords):

• Temporal lobe plasticity
• Glial cell metabolism
• Neuroinflammation
• Epilepsy
• Behaviour
• Assistant Professor - Department of Psychology, Memorial University of Newfoundland
• Assistant Professor - Department of Psychology, Mount Allison University
• Post-Doctoral Fellow Epilepsy Foundation of America Fellowship, NY

Our research is presently funded through the Natural Science and Engineering Research Council (NSERC-DG), and the Alzheimer Society of Canada (New Investigator).

Mentoring

I am currently accepting applications from highly motivated individuals for MSc or PhD training in my lab. Please visit MUN School of Graduate Studies (https://www.mun.ca/become/graduate/apply/) for more information on the application process. Deadline for submission is January 5 for Fall admission.

Career History

Education

• PhD (Distinction) - Experimental Psychology (Behavioural Neuroscience) Memorial University of Newfoundland
• Bachelor of Science - University of Calgary (Psychology)

Publications

Ghosh A, Torraville, SE, Mukherjee B, Walling SG, Martin GM, Harley CW, and Yuan Q. (2019) An experimental model of Braak’s pretangle proposal for the origin of Alzheimer’s Disease: The role of locus coeruleus in early symptom development. Alzheimer Research and Therapy. 11:59. doi: 10.1186/s13195-019-0511-2.

Quinlan MAL, Strong VM, Skinner DM, Martin GM, Harley CW, and Walling SG (2019). Locus coeruleus optogenetic light activation induces long-term potentiation of perforant path population spike amplitude in rat dentate gyrus. Frontiers in Systems Neuroscience 2:67. doi: 10.3389/fnsys.2018.00067. eCollection 2018.

Babstock DM, Walling SG, Harley CW and Malsbury CW (2018) Androgen receptor ontogeny in the dorsal hippocampus of male and female rats. Hormones and Behavior; 100:47-55 DOI: 10.1016/j.yhbeh.2018.02.014

Walling SG, Milway JS, Ingram M, Lau C, Morrison G, and Martin GM (2016) The effects of prolonged administration of norepinephrine reuptake inhibitors on hippocampal plasticity and short- and long-term memory in rats. Neurobiology of Learning and Memory; 128:92-102. doi: 10.1016/j.nlm.2015.12.013.

Lethbridge RL, Walling SG, & Harley CW (2014). Modulation of the perforant path-evoked potential in dentate gyrus as a function of intrahippocampal ß-adrenoceptor agonist concentration in urethane-anesthetized rat. Brain and Behavior, 4(1), 95-103. doi: 10.1002/brb3.199

Walling, S. G., Brown, R. A. M., Miyasaka, N., Yoshihara, Y., & Harley, C. W. (2012). Selective wheat germ agglutinin (WGA) uptake in the hippocampus from the locus coeruleus of dopamine-β-hydroxylase-WGA transgenic mice. Frontiers in Behavioral Neuroscience, 6(23). doi:10.3389/fngehav.2012.00023

Walling, S.G., Brown, R. A. M., Milway, J. S., Earle, A. G., & Harley, C. W. (2011).Selective tuning of hippocampal oscillations by phasic locus coeruleus activation in awake male rats. Hippocampus, 21(11), 1250-1262.

Publications- Awards of Scientific Merit

Canadian Institutes of Health Research: Neurosciences, Mental Health and Addiction, BrainStar (2005):

Walling SG and Harley CW (2004) Locus coeruleus activation initiates delayed synaptic potentiation of perforant path input to the dentate gyrus in awake rats: A novel -adrenergic and protein synthesis-dependent mammalian plasticity mechanism. J Neurosci 24(3): 598-604

Representative Conference Proceedings

Wasef MA, Ghosh A, Martin GM, Harley CW, Yuan Q, Skinner DM, & Walling SG (2019; accepted) Behavioural staging of a rat pretangle model of sporadic Alzheimer’s Disease (AD): Longitudinal testing of AD phenotype. Society for Neuroscience Annual Meeting, Chicago, IL

Skinner DM, Wasef MA, Cassell T, Harvey V, Baker H, Dicks H, Pomroy A, Ghosh A, Martin GM, Harley CW, Yuan Q, & Walling SG (2019, accepted) Behavioural staging of a rat pretangle model of sporadic Alzheimer’s Disease (AD): Longitudinal effects of locus coeruleus htauE14 on tests of pattern separation. Society for Neuroscience Annual Meeting, Chicago, IL

Walling SG, Wasef MA, Ghosh A, Martin GM, Harley CW, Yuan Q, Skinner DM (2019; accepted) Anatomical staging of a rat pretangle model of sporadic Alzheimer’s disease. Society for Neuroscience Annual Meeting, Chicago, IL

Ghosh A, Torraville S, Chirinos EA, Mukherjee B, McCarthy FM, Milway S, Walling S, Martin G, Harley C, & Yuan Q (2018) A rat model of pretangle Alzheimer’s disease featuring hyperphosphorylated tau in the locus coeruleus. Society for Neuroscience Annual Meeting, San Diego CA