Michael J. Berry II, Ph.D.

Research

My laboratory studies the function of the vertebrate retina – a system of neurons simple enough to be approached quantitatively, but complex enough to hold many mysteries. We would like to be able to read the visual messages encoded by ganglion cell spikes and perform visual discriminations as well as the brain. We also want to describe mathematically the computations carried out by the retina and say what was behaviorally important about those particular computations. Using a dense grid of electrodes and an algorithm that identifies ganglion cell signals arising on multiple electrodes, we have been able to record from all of the ganglion cells in a patch of the retina – a feat that has not been achieved in any other neural circuit. Visual stimuli are generated with a computer monitor and focused onto the plane of the retina, allowing a great variety of stimuli, including natural movie clips, to be presented. Together, these techniques enable us to control the input to the retinal circuit precisely and measure all of its relevant output. So far, we have found that during natural visual conditions, retinal ganglion cells fire infrequent bursts of spikes with millisecond timing precision and are completely silent otherwise. Ongoing projects in the lab seek to explore the limits of the retina's ability to recognize patterns in the visual world as well as to understand the cellular and circuit mechanisms that make these predictions possible.