Question: Is it possible for someone to turn off and on brain cells?

Ed Bracey answered on 14 Nov 2017:

Great question! Absolutely!
About 10 years ago some clever scientists took little proteins called “channelrhodopsins”, which are normally found in the cell membranes of a type of algae, and they put them into brain cells in a mouse.
Channelrhodopsins work in a similar way to the channels in cells in your eyes that detect light.
When you shine light on them, the channels open, activating the cells.
So if we put those channels into brain cells, we can shine light on them and activate them.
The special thing is that we can be really selective about which brain cells we put these channels into.
Then we can turn just those cells on and see how it changes the mouse’s behaviour. There’s also a variety now that lets you switch brain cells off.

For example, this is a video of a mouse that has had channelrhodopsin put into cells in an area of the brain that controls its movement – the motor cortex.
A small fibre optic, like a much thinner version of what’s used in fibre optic broadband cables, delivers light to the brain cells to turn them on.

As you can see, the mouse is moving around exploring the cage normally until about 0.08s, when a blue light comes on between its ears.

This is a super useful technique for helping us understanding how the brain works!