How do you measure vision?

Columbia University neuroscientist, Rudy Behnia answers the questions, how do you measure vision?



So, I think vision is really one of the most important senses that we have.

You know, we use our vision at every moment of our awake life.

And it really helps us understand the world around us and navigate the world.

And I study two particular aspects of vision, which are understanding -- The first one is to understand how we detect movement around us.

The other one is color vision, so how we manage to discriminate the different colors that are around us, you know, how is this blue, how is this green?

How can we tell?

How can we experience these different colors?

And so this is where the fruit fly comes in.

So the fruit fly is made up -- The brain of the fruit fly is made up of about 100,000 to 200,000 neurons, which is, you know, quite a bit less daunting than, you know, the amazing human brain.

So what I do is I can take a single fly that is alive and well, and I fix its head on a little platform.

It's still alive, it's still moving its legs, and I can open its skull.

You know, it's called a cuticle when it's a fly, but it's the same as your skull, as if I was opening your skull, to have access to the brain.

And then the specific fly that I'm using, I've made it so that one type of neuron is glowing green.

So maybe 800 neurons in the whole brain are gonna glow green.

And what I do is that I put this little fly that is held with its head and I put it in front of a kind of a 'fly TV.'

[ Chuckles ] It's a screen onto which I can project a variety of images.

And then I go with a recording electrode so I can record the electrical activity of these cells as the fly is seeing different visual scenes.

So we can, with this kind of experiment, can start to understand what each type of neuron is actually doing while vision is happening.