Timothy James Petros, Ph.D.


Unit on Cellular and Molecular Neurodevelopment


NIHBC 35 - PNRC I 3B-1002



Research Topics

Proper brain function requires a balance between excitatory projection neurons and GABAergic inhibitory interneurons. Interneurons are an extremely heterogeneous cell population with distinct morphologies, connectivity, neurochemical markers and electrophysiological properties. Abnormal development and function of interneurons has been linked to the pathobiology of numerous brain diseases such as epilepsy, schizophrenia and autism. Many genes implicated in brain disorders are enriched in young interneurons, and thus I believe that a thorough description of the cellular and molecular mechanisms regulating this diverse cell population is necessary to understand both normal development and disease models.

My lab is focused on understanding the how intrinsic genetic programs and environmental signals interact to generate this incredible interneuron diversity. We take a multifaceted approach to this issue, utilizing both in vitro and in vivo approaches to identify candidate mechanisms that regulate interneuron fate decisions. We strive to develop cutting edge techniques that will overcome the many challenges with studying interneuron development. Our ultimate goal is to discover genetic cascades and signaling mechanisms that direct interneuron differentiation and maturation that will act as a springboard for future research.


Dr. Petros received his B.S. from Brown University, where he began his scientific endeavors in the laboratory of J. Michael Walker utilizing mass spectrometry to identify cannabinoid-like compounds and explore their role in the suppression of pain signaling. He obtained his Ph.D. from Columbia University working with Carol Mason where he investigated the guidance factors that regulate retinal ganglion cell projections in the mouse visual system, most notably the laterality decision at the optic chiasm. From there Dr. Petros moved onto Stewart Anderson’s laboratory at Weill Cornell Medical College and utilized both in vitro stem cell techniques and in vivo electroporations to explore the mechanisms that regulate interneuron differentiation. He continued these pursuits in Gord Fishell’s laboratory at New York University where he began to untangle the intrinsic genetic programs and extrinsic environmental factors that direct interneuron diversity and maturation. He joined the NIH/NICHD as an investigator in 2017 where he plans to continue with these studies for the foreseeable future.

Selected Publications

  1. Ekins TG, Mahadevan V, Zhang Y, D'Amour JA, Akgül G, Petros TJ, McBain CJ. Emergence of non-canonical parvalbumin-containing interneurons in hippocampus of a murine model of type I lissencephaly. Elife. 2020;9.

  2. Alkaslasi MR, Piccus ZE, Hareendran S, Silberberg H, Chen L, Zhang Y, Petros TJ, Le Pichon CE. Single nucleus RNA-sequencing defines unexpected diversity of cholinergic neuron types in the adult mouse spinal cord. Nat Commun. 2021;12(1):2471.

  3. McKenzie MG, Cobbs LV, Dummer PD, Petros TJ, Halford MM, Stacker SA, Zou Y, Fishell GJ, Au E. Non-canonical Wnt Signaling through Ryk Regulates the Generation of Somatostatin- and Parvalbumin-Expressing Cortical Interneurons. Neuron. 2019;103(5):853-864.e4.

  4. Wester JC, Mahadevan V, Rhodes CT, Calvigioni D, Venkatesh S, Maric D, Hunt S, Yuan X, Zhang Y, Petros TJ, McBain CJ. Neocortical Projection Neurons Instruct Inhibitory Interneuron Circuit Development in a Lineage-Dependent Manner. Neuron. 2019;102(5):960-975.e6.

  5. Quattrocolo G, Isaac M, Zhang Y, Petros TJ. Homochronic Transplantation of Interneuron Precursors into Early Postnatal Mouse Brains. J Vis Exp. 2018;(136).

This page was last updated on October 29th, 2020