Optogenetics allows researchers to control the activation of neurons in the brain using light. Initially, fiber optic cables have been used to deliver light, but these illuminate too large an area and require the animal to be attached to a tether. Now scientists at University of Michigan have developed LED lights so small that each one can activate only one neuron at a time. These were placed along electrodes that sense the nearby electrical activity into a matrix that covers an area of the brain .
Each such matrix has 12 LEDs and 32 electrodes and have been tested already on brains of freely moving mice. Because the implant has a substantial coverage area while producing very localized single neuron activation, it can be used to study the brain’s pathways at unprecedented detail, effectively helping to realize a lot of the expected capabilities of optogenetics.
From the study abstract in journal Neuron:
Spikes were robustly induced by 60 nW light power, and fast population oscillations were induced at the microwatt range. To demonstrate the spatiotemporal precision of parallel stimulation and recording, we achieved independent control of distinct cells ∼50 μm apart and of differential somato-dendritic compartments of single neurons. The scalability and spatiotemporal resolution of this monolithic optogenetic tool provides versatility and precision for cellular-level circuit analysis in deep structures of intact, freely moving animals.
Source: University of Michigan…