μLED arrays for optogenetic stimulation of the mouse auditory cortical surface

Cortical surface stimulators are an application of µLEDs allowing spatiotemporal stimulation of genetically targeted populations of neurons in the cerebral cortex. To address challenges with the spatial resolution and density of stimulation sites, a high-precision 100-pixel µLED device was developed. The device consists of a 10 x 10 matrix addressed array of GaN µLEDs with 200 µm spacing, which emit blue light at 450 nm through a sapphire substrate. In-vivo experiments in the auditory cortex of ChR2-expressing transgenic mice have shown consistent multi-unit activity with low µLED drive current and low lateral spread of activation.