Optical recording of retinal and visual cortical responses evoked by electrical stimulation on the retina

Abstract

To develop a retinal prosthesis for blind patients using an implanted multielectrode array, it is important to study the response properties of retinal ganglion cells and of the visual cortex to localized retinal electrical stimulation. Optical imaging can reveal the spatio-temporal properties of neuronal activity. Therefore, we conducted a calcium imaging study to investigate response properties to local current stimulation in frog retinas, and a membrane potential imaging study to explore the visual cortical responses to retinal stimulation in guinea pigs. In the retina, local current stimuli evoked transient responses in the ganglion cells located near the stimulus electrode. The spatial pattern of the responding area was altered by changing the location of the stimulation. Local electrical stimulation to the retina also caused transient responses in the visual cortex. The responding cortical areas in the primary visual cortex were localized. A spatially different cortical response was observed to stimulation of a different position on the retina. These results suggest that the imaging study has great potential in revealing the spatio-temporal properties of the neuronal response for the retinal prosthesis.