Structural Clues to a Visual Function: Direction Selectivity in the Retina

October 27, 2014
11:00am-12:00pm
Davis Auditorium, CEPSR
Speaker: Sebastian Seung, Professor, Department of Computer Science/Neuroscience Institute, Princeton University

Abstract

The perception of motion is a basic visual ability, and already begins in the retina. Some retinal outputs (ganglion cells) respond selectively to stimuli moving in particular directions, but retinal inputs (photoreceptors) are not direction selective (DS). How does DS emerge from the microcircuitry connecting inputs to outputs?

In search of clues, we reconstructed starburst amacrine cells (SACs) and bipolar cells (BCs) in serial electron microscopic images with help from EyeWire, an online community of volunteer neuroanatomists.

Based on quantitative contact analyses, we found evidence that the two ends of each SAC dendrite are wired to BC types with different time lags in visual response. A mathematical model shows how such "space-time wiring specificity" could endow SACs with receptive fields that are oriented in space-time, and hence with visual responses selective to direction of motion.

Our research demonstrates how structural analysis of mammalian CNS microcircuits can lead to insights about function, and showcases novel image analysis technologies that enable the reconstruction of neural circuits at a scale that was previously impractical.

Speaker Bio

Sebastian SeungSebastian Seung completed his Ph.D. in theoretical physics at Harvard University. After postdoctoral training at Hebrew University and a stint at Bell Labs' Theoretical Physics Department, he joined MIT's Department of Brain and Cognitive Science and Department of Physics. He has been a Packard Fellow, Sloan Fellow, McKnight Scholar, and PopTech Science Fellow. Sebastian currently is a Professor of Computer Science at Princeton's Neuroscience Institute.

 

 

 

 

Hosted by Aurel A. Lazar.


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