A tiny alga has helped show how memories, feelings and behaviour form in our brains, in research by three scientists awarded the Nobel prize for physiology or medicine this month.
Chlamydomonas is a one-celled alga that swims towards light using a light-sensing protein called channelrhodopsin, remarkably similar to the rhodopsin in our eyes. When the channelrhodopsin detects light, electrically charged ions rush into the cell from outside, triggering an electrical signal incredibly fast that tells the alga to move with its hair-like motor.
In the research, the gene for the Chlamydomonas channelrhodopsin was transferred into living animal brain cells and flashes of light were used to switch individual neurons on or off, helping pinpoint the exact circuits in the brain that control behaviour, feelings, memories, movements, waking and sleeping, and other bodily functions. It could even switch on how mice gather their young in a nest or groom them.
This technique is being used to investigate disorders such as depression, anxiety and Parkinson’s disease, and is being tested to partially restore vision in people with diseases of the retina. All of this stemming from esoteric studies of a humble alga.