Abstract
Purpose::
Visual prosthesis based on optic nerve stimulation with penetrating microelectrode array was proposed as a potential remedy of the blindness caused by retina diseases, such as RP or AMD. This study is to investigate the spatial distribution of active intensity in rabbit visual cortex by electrical stimulation in different sites and patterns in optic nerve, and to explore the possible relationship between the visual and electrical stimulation.
Methods::
Albino rabbits with body weights of 2.5~3.5 kg were used as animal model. Craniotomy was performed on the rabbit occipital to expose the visual cortex. A home-made 18-microelectrode array of adjustable inserting depth was implanted to record the neural activities of visual cortex. Multi-site recording by visual stimulations in predetermined experimental protocol was performed. Then orbital surgery was performed to expose the optic nerve. Four tungsten electrodes (Φ=100µm) were penetrated into the intraorbital optic nerve in sequence along the axis at different sites. The multi-site responses to single electrode and multi-electrode stimulation were studied in predetermined stimulating protocol via the 18-microelectrode array recording, respectively.
Results::
Spatial distributions of active intensity in rabbit visual cortex were remarkably different, by both adjusting the parameters of stimulating patterns in one identical electrode and stimulating different sites in optic nerve. We also observed the responding activities in rabbit visual cortex corresponding to both the visual stimulation and electrical stimulation in optic nerve. By comparing the similarities and differences between the visual-induced and electrical-induced activities of visual cortex, we could find some possible relationship between visual and electrical stimulation. Some electrical stimulation in certain site of optic nerve could be mimicked by part-field visual stimulation.
Conclusions::
Optic nerve stimulation with penetrating microelectrode array is a feasible way to elicit multi-site activities of rabbit visual cortex. The spatial distribution of active intensity in rabbit visual cortex depends on different stimulating protocols.
Keywords: electrophysiology: non-clinical • visual cortex • electrophysiology: non-clinical