Information processing in a simple network: What the humble retina tells the brain

Time/Room: Friday, May 13, 2016, 5:00 – 7:00 pm, Talk Room 1-2
Organizers: Scott Nawy, PhD, University of Nebraska Medical Center and Anthony Norcia, Stanford University
Presenters: Greg Field, Michael Crair, William Guido, Wei Wei

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This year’s biennial ARVO at VSS symposium features a selection of recent work on circuit-level analyses of retinal, thalamic and collicular systems that are relevant to understanding of cortical mechanisms of vision. The speakers deploy a range of state-of-the art methods that bring an unprecedented level of precision to dissecting these important visual circuits.

Circuitry and computation in the mammalian retina.

Speaker: Greg Field; USC

The mammalian retina is composed of ~80 distinct neuronal cell types. These neurons work in concert to parcel visual information into ~30 different RGC types, each of which transmits a different message about the visual scene to the brain. I will describe ongoing work in my lab to define the functional role of different cell types in the mammalian retina via the combination of large-scale multi-electrode array recordings and chemogenetic manipulation of genetically defined cell types. This combination of approaches is revealing the specialized roles played by different cell types to encode visual scenes for perception and behavior.

Retinal activity guides visual circuit development prior to sensory experience

Speaker: Michael C. Crair; Yale

Classic models emphasize an important role of sensory experience in the development of visual circuits in the mammalian brain. However, recent evidence indicates that fundamental features of visual circuits in the thalamus, cortex and superior colliculus emerge prior to the emergence of form vision. I will summarize our latest experiments that use in vivo optical imaging techniques and molecular-genetic manipulations in mice to demonstrate that spontaneous retinal activity, generated prior to vision, plays an essential role in sculpting the development of visual circuits in the mammalian brain.

Dissecting circuits in the mouse visual thalamus.

Speaker: William Guido; University of Louisville

The contemporary view of the dorsal lateral geniculate nucleus (dLGN) of thalamus is that of a visual relay, where the gain of signal transmission is modulated by a diverse set of inputs that arise from non-retinal sources. I will highlight our recent studies in the mouse, an animal model that provides unprecedented access into the circuitry underlying these operations.

Neural mechanisms of direction selectivity in the retina

Speaker: Wei Wei; Department of Neurobiology, The University of Chicago
Authors: Qiang Chen, David Koren and Wei Wei, Department of Neurobiology, The University of Chicago

The direction selective circuit in the retina computes motion directions and conveys this information to higher brain areas via the spiking activity of direction selective ganglion cells. While multiple synaptic mechanisms have been implicated in the generation of direction selectivity in the retina, it is unclear how individual mechanism modulates the firing patterns of direction selective ganglion cells. Here, we aim to unambiguously differentiate the contributions of distinct circuit components to direction selectivity by loss-of-function studies using genetic, electrophysiological and functional imaging methods. Our results highlight the concerted actions of synaptic and cell-intrinsic mechanisms required for robust direction selectivity in the retina, and provide critical insights into how patterned excitation and inhibition collectively implement sensory processing in the brain.

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