Raising the stakes for cortical visual prostheses

In this issue of the JCI, the dream of restoring useful vision to blind individuals with neurotechnology moves one step closer to realization. Fernandez et al. implanted an electrode array with 96 penetrating electrodes in the visual cortex of a blind patient who had been without light perception for 16 years due to optic neuropathy. Remarkably, the patient was able to perceive visual patterns created by passing current through array electrodes. The use of a penetrating electrode array meant that action potentials from single neurons could be recorded to study the neural response to stimulation. Compared with electrodes resting on the cortical surface, penetrating electrodes require one-tenth the current to create a visual percept. However, patterned electrical stimulation often fails to produce the expected percept for penetrating and surface electrode arrays, highlighting the need for further research to untangle the relationship between stimulus and perception.
Electrical stimulation of the visual cortex Neurosurgeons probing the brains of awake patients in the operating room discovered that electrical stimulation of early visual cortex produces the perception of a [...]