Christopher S. Leonard, Ph.D., leads a lab in which brain circuits regulating arousal, sleep and motivation and how they adapt in disorders such as narcolepsy and addiction are studied. As an undergraduate at Northeastern University in Boston, his passion for neuroscience was sparked by working with psychiatric in-patients at Massachusetts Mental Health Center, by studying eye movements with Alex Skavenski in the Department of Psychology and by studying visual psychophysics with Ernst Wolf at the Massachusetts Eye and Ear Infirmary. As a Ph.D. student with Jerry Simpson at NYU/Langone Medical Center, Dr. Leonard studied how global retinal image motion is processed along pathways to the cerebellum in order to control compensatory eye movements. As a post-doctoral fellow with Rodolfo Llinàs, he worked on synaptic transmission at the squid giant synapse at the MBL in Woods Hole, Massachusetts, and began his long-term interests in how ion channels regulate neuronal firing properties and how transmitter neuromodulation of these channels impacts these properties.

Education

• B.S. with Honors, Psychology, Northeastern University
• Ph.D., Physiology and Biophysics, New York University (NYU)
• NIH Postdoctoral Fellowship, Physiology and Biophysics, NYU Medical Center

Research

Dr. Leonard's research is currently focused on understanding novel actions of orexin neuropeptides on their targets in the ascending arousal system and the effect of morphine addiction on hypothalamic orexin neurons and their inputs and outputs. At a cellular level, the researchers at his lab utilize whole-cell patch clamp recordings and simultaneous intracellular Ca2+ imaging methods in brain slices. At a circuit level, they utilize optogenetic and chemogenetic probes expressed by viral vectors to study the operation of circuits regulating sleep and motivation. At the behavioral level, they use optogenetics and receptor knockouts to investigate the function of specific cell populations in regulating behavioral states. Through these approaches, the researchers at Dr. Leonard's lab are advancing understanding of the biological underpinnings of sleep, arousal and motivation and their associated pathologies.

Publications

• Q Zhu, A Mishra, JS Park, D Liu, DT Le, SZ Gonzalez, .... "Human cortical interneurons optimized for grafting specifically integrate, abort seizures, and display prolonged efficacy without over-inhibition." Neuron 111 (6), 807-823. e7, 2023
• Y Cissé, M Ishibashi, J Jost, H Toossi, L Mainville, A Adamantidis, .... "Discharge and role of GABA pontomesencephalic neurons in cortical activity and sleep-wake states examined by optogenetics and juxtacellular recordings in Mice." Journal of Neuroscience 40 (31), 5970-5989, 2020
• M Isibashi, A Fukuda, CS Leonard. "Dynamic Clamp Investigations of the Arousal Peptide Orexin on Dorsal Raphe Neurons." Cell 52 (9), 50, 2020
• Y Cissé, H Toossi, M Ishibashi, L Mainville, CS Leonard, A Adamantidis, .... "Discharge and role of acetylcholine pontomesencephalic neurons in cortical activity and sleep-wake states examined by optogenetics and juxtacellular recording in mice." Eneuro 5 (4), 2018
• S Ma, B Hangya, CS Leonard, W Wisden, AL Gundlach. "Dual-transmitter systems regulating arousal, attention, learning and memory." Neuroscience & Biobehavioral Reviews 85, 21-33, 2018
• M Ishibashi, I Gumenchuk, K Miyazaki, T Inoue, WN Ross, CS Leonard. "Hypocretin/orexin peptides alter spike encoding by serotonergic dorsal raphe neurons through two distinct mechanisms that increase the late afterhyperpolarization." Journal of Neuroscience 36 (39), 10097-10115, 2016
• M Ishibashi, I Gumenchuk, B Kang, C Steger, E Lynn, NE Molina, .... "Orexin Receptor Activation Generates Gamma Band Input to Cholinergic and Serotonergic Arousal System Neurons and Drives an Intrinsic Ca2+-Dependent …." Frontiers in Neurology 6, 120, 2015

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Professional Service

• SOM Tenure, Appointment, & Promotions Committee
• SOM Education and Curriculum Committee
• SOM Strategic planning Committee
• SOM Research Support Services Committee (Chair)
• NYMC Grievance Committee
• NYMC Faculty Senate
• Student Academic Performance Committee [SAPRC]

Teaching Responsibilities

• Medical Neuroscience (SOM)
• Graduate Physiology (GSBMS)
• Dental Physiology (TCDM)