DeVries Lab

Departments of Ophthalmology and Neuroscience

Northwestern University Feinberg School of Medicine

The mammalian retina

The retina is an ideal tissue in which to study how the nervous system processes information because it has a laminar structure with inputs that are readily stimulated by patterns of light.  We use advanced techniques including optogenetics, cell pair recording, super-resolution imaging, and computational modeling to study how visual stimuli are processed by groups of retinal neurons.  


Synapse Form and Function

The design of the vertebrate cone photoreceptor synapse is honed by over 300 million years of evolution to accomplish two tasks, the transmission of the visual signal in daylight and the distribution of the signal into more than a dozen pathways for parallel processing.  We have developed two approaches that allow us to study transmission and parallel signaling at the cone synapse in nanoscopic detail.  The first approach uses dual whole-cell patch clamp recording and allows us to track the release of an individual transmitter quantum by a cone and simultaneously measure the response to that quantum in each of the postsynaptic bipolar cell types.  The other approach uses super-resolution microscopy to spatially localize the cleft proteins that shape transmission including those associated with transmitter release, postsynaptic response, and transmitter reuptake.  Our most recent work shows how different spatiotemporal patterns of transmitter release at the cone synapse can activate different types of bipolar cells.

First Steps in Color Vision

Most mammalian retinas contain two types of cones, one expressing a photopigment that responds best to green light (or green and red light in trichromatic primates) and the other that responds best to blue/UV light.  The two types of cones have structurally distinct synaptic terminals and, with minor exceptions, transmit their signals over different bipolar cell pathways to the inner retina.  Our lab studies how signals are processed differently at blue and green cone synapses and how the different types of synaptic contacts are established.  We also trace the blue and green circuits to their destinations in the inner retina.

Inner retinal circuits

There are approximately 40 types of retinal ganglion cells each tuned to respond best to different features in the visual scene.   Tuning arises through contacts with specific subsets of bipolar and amacrine cells whose processes ramify in the dense innerplexiform layer.  Determining the subsets of bipolar and amacrine cells that provide inputs to specific ganglion cell types, and the properties of those inputs, is a major challenge.  Together with my collaborator, Dr Yongling Zhu, we address this challenge by using a combination of monosynaptic rabies pathway tracing and optogenetic circuit interrogation.