Optogenetics has become a popular technique for studying neural circuits in recent years by allowing the optical control of genetically targeted neurons.

In order to maximise the impact of this technique, new technologies are needed to optically stimulate deep brain structures in a site-specific fashion. We have microfabricated needle shaped penetrating micro-probes from a gallium nitride quantum well structure on a silicon substrate. The probes measure 30 µm in thickness, 100 µm in width and each shank contains sixteen individually addressable 25 µm-diameter LEDs in a linear arrangement.

While being minimally invasive, these devices allow precise spatiotemporal patterns of optogenetic neural activation, as demonstrated in vivo in mouse cortex.

Schematic showing the single-shank probe dimensions and a picture of the six-shank probe in operation