One of the fundamental challenges in monitoring and modulating central nervous system activity is the lack of tools for simultaneous non-invasive interrogation of local neuronal ensembles in different regions of the brain. Despite recent advances in neural modulation techniques, including a rapidly expanding optogenetic and imaging toolset, we still lack a robust, minimally- invasive optogenetic stimulation platform. The ability to independently deliver light to multiple highly-localized regions of the brain would drastically improve in vivo optogenetic experiments. Illuminating a large volume of brain using light sources above the brain surface does not provide the requisite spatial resolution, and since the intensity diminishes rapidly only a small fraction of target neurons in the vicinity of the light source (~200 µm) will be excited. Increasing the light source power, conversely, results in the generation of excessive heat in the brain and the potential for tissue damage. This project uses specially designed up-converting nanocrystal particles (UCNP) to deliver light locally to neurons. We use an acoustic-optics modality to deliver and steer light in the brain from outside without causing damage to the brain tissue.
Project end date: 08/12/16