Secrete

A way to link unconnected neurons in the brain and change an organism’s behavior, dubbed neural engineering, could one day help treat spinal injuries.

Michael Krieg at the Institute of Photonic Sciences in Spain wanted to devise a non-invasive alternative, using light as a neurotransmitter. In a typical brain, neurotransmitters are chemicals that are secreted into the gap between two neurons, also known as a synapse, allowing them to communicate.

Krieg and his colleagues figured out a way to do this using particles of light, called photons, in some of the synapses of a nematode worm.

To do this, the researchers genetically engineered some of the worm’s neurons so that they didn’t produce any neurotransmitters when activated. They also modified two types of protein present on either side of a synapse, called the presynapse and postsynapse, that normally send and receive neurotransmitters.

The genetically engineered presynapse produced an enzyme that releases photons when activated, while the modified postsynapse produced a protein that responds to photons and fires a second neuron.