Scientists have combined lasers and genetics to encourage mice to run in circles, form false memories of fearful experiences in flies, and stop worms from wiggling through light-stimulation techniques. Now, the use of lasers in neuroscience has even led scientists to control flirting in flies.
A new Fly Mind-Altering Device (FlyMAD) uses tracking technology to pass an infrared light through exoskeletons of genetically modified flies to control their behaviour.
It is hoped that this field of optogenetics will offer a biological explanation of how the human brain works, eventually mapping neurological disorders involved in depression, schizophrenia and Alzheimer’s.
The human brain is a dense network of interwoven cells, controlled by intricately timed electrical signals and biochemical messengers. The greatest obstacle to understanding it is our inability to break down its complexity. Electrical stimulation is too crude a tool that sparks all circuitry in one location, whilst drugs act too slowly to be useful in studying brain activity in real time. To best crack the secrets of the brain, we need a way of controlling one cell type at a time.
The idea of using light to stimulate individual neurons originated with the famous DNA decoder Francis Crick in the 80s. He suggested that light could be the key to targeting specific brain cells. However, the challenge lay in making particular neurons in animal brains light sensitive.
It was only in 2004 that research teams working in two separate fields realized, by a brilliant stroke of luck, that they could combine their research to solve this problem. One research team isolated the genetic sequence for a light-sensitive protein from green algae, whilst another transferred the genetic sequence into animal cells in culture, which then began to express the protein in their cell walls. When light was shone onto the cells the proteins would immediately activate the neurons. With a lot of hard work and a bit of genius thrown in, scientists had made a huge leap in developing a technique that could help decode the human brain.
Using this technique, scientists can now evoke behavioural responses in freely moving animals by remotely activating these light-sensitive neurons with lasers. Researchers believe these methods can be used to discover what neurons control decision-making in animals, and eventually unravel the mysteries of the mammalian mind. Optogenetics has already shed light on the neurological processes in Parkinson’s disease, autism and drug abuse.
Should we be worried about the dangers posed by an army of mind-controlled mice in the near future? Probably. Should we be excited about finally understanding how our minds work? Definitely.