2016 Finalist Arjun Krishnaswamy, Ph.D. Postdoctoral Fellow Harvard University

Arjun Krishnaswamy received his undergraduate and Ph.D. degrees from McGill University in Montreal, Canada. Under the mentorship of Dr. Ellis Cooper, he studied the role of activity in synapse formation in the peripheral nervous system. For his postdoctoral work with Dr. Joshua Sanes, he studied how retinal neurons choose their synaptic partners to create circuits attuned to visual features such as motion. He is starting his own lab at McGill University where he will extend his work and learn more about neural circuit assembly.

Building Brains
Wiring specificity is a critical step in the assembly of the nervous system that requires developing neurons to choose appropriate synaptic partners. The rules and mechanisms that govern these choices are not fully understood. To learn more, Arjun Krishnaswamy combined optogenetic, physiological and molecular-genetic methods to study the assembly of layered circuits of the mouse retina. His results show that developing neurons first choose a layer in which to extend their processes and then choose to synapse with a subset of nearby targets. Each choice is directed by a distinct family of recognition molecules; members of the cadherin family direct layer specific choices and members of the immunoglobulin superfamily direct target specific ones. These results outline a speculative but testable model in which combinations of cadherins, IgSFs and perhaps other recognition molecules are used in combinations to direct connectivity among the ~130 retinal types and assemble retinal circuits. Future work will address this model and test its generality at higher centers in the brain.

For Dr. Krishnaswamy‘s full essay, see Science online atsciencemag.org