Alexander Sher, myself, Philip Huie, Yannis M. Paulus, Loh-Shan S. Leung, Hiroyuki Nomoto, Robert E. Marc and Daniel Palanker have a new manuscript out in the Journal of Neuroscience.
This manuscript explores the extent of functional restoration of the retinal network including the questions of re-establishment of synaptic connections by migrating photoreceptors with the deafferented bipolar cells located inside the lesion, and the extent of the functional restoration of the OFF- and ON- pathways within the retina. The restoration of retinal circuitry and responses not only demonstrate the existence of constructive adult mammalian retinal plasticity leading towards restoration of normal retinal circuitry after injury, but it also reveals a new approach to the clinical practice of laser-photocoagulation to treat diabetic retinopathy and wet forms of age-related macular degeneration (AMD) as well as other vascular diseases of the retina. Essentially, instead of using a broad laser beam to burn and seal off large areas of retina, we used patterned laser beams to cut thin channels and allowing adjacent photoreceptors to migrate into the channels, preventing complete loss of vision in those regions. The effect of photoreceptor migration over the laser lesion opens the door to immediately relevant, new clinical approaches to retinal photocoagulation therapy which would allow restoration of continuity of the photoreceptor layer, thereby avoiding the retinal scarring and loss of vision in those regions
The plasticity questions are interesting and have multiple significant implications. A large number of studies rely on retinal laser lesions as a model for investigation of cortical plasticity, assuming that retinal function in the lesions is lost permanently. Restoration of retinal sensitivity in the lesions might affect interpretations of these studies. Furthermore, the process of reconnection between photoreceptors and the inner retinal neurons is important for guiding studies aimed at restoration of sight in degenerate retina through genetic manipulation of the existing or surgical reintroduction of new retinal cells.