Optogenetics: the hot new neuro tool

Optogenetics is a hot buzzword in the world of neuroscience, but it's hardly considered a household word. So what is this futuristic sci-fi-sounding topic and why should you care? I'd like to give you a taste of what it is and the potential it holds in a 3-minute summary.

Optogenetics is a novel technique which, with the flash of a light, allows us to control the electrical activity of one or many neurons. And it comes from a surprising source: pond scum.

Magnified green algae, aka pond scum

Pond scum, otherwise known as green algae, express a molecule on their surfaces that enable them to convert sunlight into an electric signal. A little more than a decade ago, some clever neuroscientists in Stanford thought to themselves, "What if we took that pond scum gene and inserted into neurons? Might we be able to then use light to control the electrical activity of neurons?" And you know what? It worked!

Some clever neuroscientists thought to themselves, "What if we took that pond scum gene for a molecule that converts light into electricity, and inserted into neurons? Might we be able to then use light to control the electrical activity of neurons?"(Image from nsf.gov)

In labs across the world, optogenetics is being applied for a variety of different applications. Neuroscientists have genetically modified many different classes of neurons to express optogenetic molecules for different experiments. This has enabled them to, all with the flick of a switch, make normally behaving mice suddenly start running in circles, relieve depression in mice, calm anxious mice, or eliminate trembling in mice suffering from Parkinsons-like symptoms. They have even used optogenetics to target and selectively erase specific memories. And that's only a few examples.

A fiber optic is implanted in a genetically-modified mouse brain in order to deliver light directly to the genetically-modified neurons expressing optogenetic molecules in order to control the activity of these neurons with light.

(This image has been widely circulated across the internet, so I don't know which source to site. Just google "optogenetic mouse" to see for yourself.)

So that's all fine, but what does tinkering with a bunch of lab rats—er, mice—mean for you and me? Well, just a couple of months ago, in early 2016, the first human underwent optogenetic therapy as part of a new clinical trial starting in the United States. This woman, who has lost her vision, hopes to have light sensitivity restored thanks to optogenetic molecules that should soon be expressed in her eye. If it works, it will be the first proof that optogenetics can be used in medicine. Potential future applications lie in many diseases and conditions across the board, including Parkinson's Disease, anxiety, chronic pain, depression, even cancer.

This may be the first you've heard of optogenetics, but I suspect it won't be the last.