https://www.sciencedaily.com/releases/2019/08/190805143525.htm

Researchers, publishing in Nature Biomedical Engineering, believe the device can speed up efforts to uncover brain diseases such as Parkinson's, Alzheimer's, addiction, depression, and pain.

The device, using Lego-like replaceable drug cartridges and powerful bluetooth low-energy, can target specific neurons of interest using drug and light for prolonged periods.