Abstract
Detection of image focus is critical to emmetropization during development and the dysfunction of this feedback system leads to refractive disorders. A similar focus signal drives accommodation in the developed visual system. Focus detection begins in the retina, and in the case of emmetropization, the retinal signal is sufficient to drive the phenomenon, but the neural mechanism responsible for this important function has remained elusive. I will describe work from my lab that has identified a new retinal ganglion cell type in mouse called the “ON delayed” cell whose properties are well suited to report the global focus of the retinal image. We used electrophysiology and pharmacology during visual stimulation of the ex vivo retina to study the circuits upstream of the ON delayed ganglion cell. These experiments revealed several non-canonical circuit motifs including novel roles for inhibition and disinhibition in shaping ganglion cell responses. I will discuss our ongoing efforts to generate molecular tools for manipulating this putative focus circuit in vivo.