Final Activity Report Summary - OPTICAL NEUROCONTROL (Flexible optical control of neural circuits)
Among the most common causes of blindness are degenerative diseases of the outer retina, like Retinitis Pigmentosa and Age-Related Macular Degeneration - major causes of blindness, with a global toll of 25-30 million people. Diseases of the outer retina damage the light-sensitive cells called photoreceptors, but not the inner retinal neurons and the optic nerve. A retinal neuroprosthetic device will bypass the dead photo-receptors and provide an artificial sense of vision by translating the visual scene directly into patterns of neuron activity, much as cochlear implants for the deaf already translate sounds into patterns of activity in auditory nerves. In February 2007, a first-generation electrode-array manufactured by Second Sight Corporation passed early tests in five blind individuals, and is currently moving towards testing in a larger patient population.
Our approach to stimulating retina neurons is very different, and is based on using patterns of light rather than electrical currents to stimulate the neurons. There are actually now several different ways possible for activating nerve cells directly using light, and the research project focused on developing optical systems that can translate visual scenes into many-neuron activity patterns.
One of the most promising methods is based on inserting a light-sensitive ion channel called ChannelRhodopsinII into the cells' membrane, and we have demonstrated for the first time how these retinas can be activated using patterns of blue light. Our project focused on proof-of-concept experiments, where we tested the operating principles of the devices using isolated rat retinas. In parallel, we have been developed a first engineering prototype of a neuroprosthetic system that will generate appropriate patterns of light for mimicking natural vision.
Our approach to stimulating retina neurons is very different, and is based on using patterns of light rather than electrical currents to stimulate the neurons. There are actually now several different ways possible for activating nerve cells directly using light, and the research project focused on developing optical systems that can translate visual scenes into many-neuron activity patterns.
One of the most promising methods is based on inserting a light-sensitive ion channel called ChannelRhodopsinII into the cells' membrane, and we have demonstrated for the first time how these retinas can be activated using patterns of blue light. Our project focused on proof-of-concept experiments, where we tested the operating principles of the devices using isolated rat retinas. In parallel, we have been developed a first engineering prototype of a neuroprosthetic system that will generate appropriate patterns of light for mimicking natural vision.