Graduate Neuroscience Program

William D. “Trey’” Todd headshotWilliam D. “Trey’” Todd


B.S., Neuroscience: Baylor University, 2005.

M.A., Psychology: The University of Iowa, 2009.

Ph.D., Psychology (Behavioral and Cognitive Neuroscience): The University of Iowa, 2012.
Mentor: Mark S. Blumberg.

Postdoctoral (Sleep, Circadian, and Respiratory Neurobiology): Harvard Medical School and Beth Israel Deaconess Medical Center, 2012-2019. Mentor: Clifford B. Saper.


Research Interests:

Circadian rhythms are an evolutionary adaptation to Earth’s 24-hour rotation and the resulting light-dark cycle.  The central circadian clock, located within the hypothalamus of the mammalian brain, senses such daily light-dark rhythms via direct photic input from the retina and, in turn, synchronizes physiological and behavioral rhythms to the 24-hour day.  Using transgenic mouse models and genetically targeted mapping and manipulations, my lab seeks to understand how this central circadian clock (and its input and output pathways) regulates such daily biological and behavioral timing, from sleep-wake rhythms to more complex behaviors including aggression.  

My postdoctoral work with Clif Saper at Harvard Medical School demonstrated that mice exhibit a daily rhythm in their propensity to attack an intruder mouse and revealed a novel hypothalamic circuit by which the central circadian clock influences neurons that promote attack behavior.  One major focus of my lab is how such circuitry may be involved in neurobehavioral pathologies associated with circadian dysfunction and behavioral aggression such as “sundowning syndrome” in Alzheimer’s disease and related dementias, which is characterized by agitation and aggression during the early evening.  

In addition to this ongoing work, I have a strong interest in developmental and comparative issues in circadian behavioral neuroscience, particularly in regard to differences between diurnal (day-active, such as humans) and nocturnal (night-active) species.  Indeed, my graduate work with Mark Blumberg at the University of Iowa revealed that species differences in retinohypothalamic projections are associated with the developmental emergence of species-typical circadian behavior and hypothalamic activity in nocturnal Norway rats and diurnal Nile grass rats.  In the future my lab will seek to incorporate similar developmental and comparative approaches in the context of the research questions above in order to better understand the implications for human neural disorders, as well as for foundational questions regarding the evolution of neural processes underlying behavior.



Integrative Physiology (ZOO 4125) and Human Systems Physiology (ZOO 3115)



Venner A, Broadhurst RY, Sohn L, Todd WD, and Fuller PM. Selective activation of dorsal raphe serotonergic dorsal raphe neurons facilitates sleep through anxiolysis. SLEEPJ. 2019, zsz231, 1-12.

Venner A, Todd WD, Fraigne J, Eban-Rothschild A, Bowery H, Kaur S, and Anaclet, C. Novel sleep-wake and circadian pathways for therapeutic potential. SLEEPJ. 2019. 42 (5): 1-14. Invited review.

Todd WD* and Machado NL. A time to fight: circadian control of aggression and associated autonomic support. Autonomic Neuroscience: Basic and Clinical. 2019. 217: 35-40. Invited review. *Corresponding author.

Todd WD, Fenselau H, Wang JL, Zhang R, Machado NL, Venner A, Broadhurst RY, Kaur S, Lynagh T, Olson DP, Lowell BB, Fuller PM, Saper CB. A hypothalamic circuit for the circadian control of aggression. Nature Neuroscience. 2018. 21(5); 717-724.

Blumberg MS, Gall AJ, and Todd WD. The development of sleep-wake rhythms and the search for an elemental circuit. Behavioral Neuroscience. 2014. 128; 250-63. Invited review.

Gall AJ, Todd WD, and Blumberg MS. Development of SCN connectivity and the circadian control of arousal: A diminishing role for humoral factors? PLoS One. 2012; 7(9), e45338.

Todd WD, Gall AJ, Weiner JA, and Blumberg MS. Distinct retinohypothalamic innervation patterns predict the developmental emergence of species-typical circadian preference in nocturnal Norway rats and diurnal Nile grass rats. Journal of Comparative Neurology. 2012. 502; 3277-92.

Campi KL, Collins CE, Todd WD, Kaas J, and Krubitzer L. Comparison of area 17 cellular composition in laboratory and wild-caught rats including diurnal and nocturnal species. Brain Behavior and Evolution. 2011; 77:116-30.

Todd WD, Gibson JL, Shaw CS, and Blumberg MS. Brainstem and hypothalamic regulation of sleep pressure and rebound in newborn rats. Behavioral Neuroscience. 2010; 124:69-78. *See also special comment in same issue: Corner MA. The sleep-like nature of early mammalian behavioral rhythms. Behavioral Neuroscience. 2010; 124:69-78.

Gall AJ, Todd WD, Ray B, Coleman CM, and Blumberg MS. The development of day-night differences in sleep and wakefulness in Norway rats and the effect of bilateral enucleation. Journal of Biological Rhythms. 2008; 23:232-41.

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