Researchers have developed a tiny flexible probe with light-emitting diodes (LEDs) that can be safely inserted into the brain tissue of free-roaming mice (Kim TI et al. Science. 2013;340:211-216). The wireless probe is intended for studying neural circuits in optogenetic studies, which use genetically engineered animals with neurons that respond to pulses of light.
Such studies allow researchers to analyze and to affect precise brain functions in isolation in ways that are impossible with electrical stimulation or drugs. The ultrathin probe's size allows investigators to insert it deep within the brain, where it can trigger select neurons without causing damage.
Hampton T. Shining a Light on the Brain. JAMA. 2013;309(21):2205. doi:10.1001/jama.2013.5956