Retinal receptive-field substructure: scaffolding for coding and computation

The center-surround receptive field of retinal ganglion cells represents a fundamental concept for how the retina processes and encodes visual information. Yet, traditional approaches of using the receptive field as a linear filter to integrate light intensity over space often do not capture the responses of a ganglion cell to complex visual stimuli. Thus, models with local nonlinearities in subunits of the receptive field or with local temporal dynamics are emerging to better reflect relevant aspects of retinal circuitry and capture stimulus encoding. Here, we review recent efforts to identify such receptive-field substructure and evaluate its role in visual stimulus encoding. The concomitant development of new computational tools may pave the way toward a model-based, functional approach to retinal circuit analysis.