Neurobiology of the Eye
Responses of ganglion cells of the retina to defocus, as recorded with the MEA
While many data are available on how ganglion cells respond in the isolated retina to various light stimuli, little is known about whether they can distinguish a general loss of contrast from defocus. A previous study from our lab in the chicken retina had shown that they can’t – a reduction in their spiking rates with increasing defocus was fully predictable from the modulation transfer function for a defocused optical system (Diedrich and Schaeffel 2009).
However, the optical stimuli were just phase-reversing checkerboards (see picture MEA1 and MEA2), and it is known that spatially stationary stimuli are not very representative, given that the retinal image is in continuous motion. Therefore, the current attempt involves movies that are defocused or low pass filtered with a point spread function calculated from defocus. The mouse retina is currently the model.
No decision yet.
Frank Schaeffel, Stefan Harmeling, Bernhard Schöllkopf (both Max-Planck Institute for biological cybernetics, Tuebingen).
BMBF, Bernstein center of computational neuroscience, Tübingen (scientific coordinator: Matthias Bethge).