Existing methods for controlling brain activity tend to skew the results by their very nature -- it's difficult to behave normally with a wad of optical fibers or electrical wires in your head. The University of Illinois and Washington University have developed a much subtler approach to optogenetics that could lift that weight from the mind in a very literal sense. Their approach inserts an extra-thin ribbon into the brain with LEDs that are about as big as the neurons they target, stimulating deeper parts of the mind with high precision and minimal intrusion; test mice could act as if the ribbon weren't there. The solution also lets researchers detach the wireless transceiver and power from the ribbon to lighten the load when experiments are over. Practical use of these tiny LEDs is still a long ways off, but it could lead to both gentler testing as well as better treatment for mental conditions that we don't fully understand today.