Understanding the building blocks of neural computation: Insights from connectomics and theory

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Friday, November 1, Giedt 1003, 12:10pm-1:00pm

Speaker: Dmitri (Mitya) Chklovskii
Howard Hughes Medical Institute

Host: Professor Erkin Seker

Abstract:

Animal behavior arises from computations in neuronal circuits, but our understanding of these computations has been frustrated by the lack of detailed synaptic connection maps, or connectomes. For example, despite intensive investigations over half a century, the neuronal implementation of local motion detection in the insect visual system remains elusive. We developed a semi-automated pipeline using electron microscopy to reconstruct a connectome, containing 379 neurons and 8,637 chemical synaptic contacts, within the Drosophila optic medulla. By matching reconstructed neurons to examples from light microscopy, we assigned neurons to cell types and assembled a connectome of the repeating module of the medulla. Within this module, we identified cell types constituting a motion detection circuit, and showed that the connections onto individual motion-sensitive neurons in this circuit were consistent with their direction selectivity. Our identification of cell types involved in motion detection allowed targeting of extremely demanding electrophysiological recordings by other labs. Preliminary results from such recordings are consistent with a correlation-based motion detector. This demonstrates that connectomes can provide key insights into neuronal computations.

Biography:

Dr. Chklovskii was born in St. Petersburg, Russia, and studied physics and engineering in college. He moved to the US in 1989 and obtained a PhD in theoretical physics from MIT in 1994. After being a Junior Fellow at Harvard Society of Fellows he decided to make a switch to theoretical neurobiology and was a Sloan Fellow at the Salk Institute. In 1999, Dr. Chklovskii founded a theoretical neuroscience group at Cold Spring Harbor Laboratory, where he was an Assistant and then Associate Professor. He moved to Janelia Farm in 2007. His main interest is in building simple but powerful theories of brain structure and function. (Bio from janelia.org)


About the seminar:
This seminar is part of the Fall EEC 290 seminar series and is open to all.