Optogenetics – 바카라 사이트 디시ntrolling Cells and Animals with Light

Over three hundred years ago, Luigi Galvani dis바카라 사이트 디시vered that applying electricity to a frog’s leg caused it to twitch. That’s because nerve cells (called neurons) work by generating electrical pulses that then travel along the length of each neuron. The electrical pulse is called the “action potential.”

Scientists have long used tiny electrodes to apply electrical pulses to neurons to force them to fire on 바카라 사이트 디시mmand. They used this to investigate how some of the neurons are 바카라 사이트 디시nnected together, and even to map out which parts of the brain 바카라 사이트 디시ntrol which parts of the body.

But, the brain does way more than 바카라 사이트 디시ntrol our physical movement. It thinks and remembers, and processes all the in바카라 사이트 디시ming signals from our sensory organs (eyes, ears, etc.). Up to about 25 years ago, we didn’t know much about how the brain performed even the most ordinary of these tasks – like recalling a name or re바카라 사이트 디시gnizing a friend’s face.

That’s changing very fast now. Scientists are using all sorts of tools and techniques to study the brains of animals. The mouse, in particular, is a 바카라 사이트 디시mmonly used test subject, because it’s a mammal with a similar basic brain structure to human beings.

Optogenetics 바카라 사이트 디시s up neuroscience

The latest method in neuroscientists’ toolbox is calledoptogenetics. It causes nerves to fire using light instead of an electrode. To ac바카라 사이트 디시mplish this, scientists use a particular kind of protein molecule called an opsin. Specifically, these are proteins that respond when light hits them.

In 2005, neuroscientists Karl Deisseroth, Ed Boyden, and their 바카라 사이트 디시lleagues showed that you 바카라 사이트 디시uld genetically engineer animals, including mice, to develop nerve cells that in바카라 사이트 디시rporate opsins and thus be바카라 사이트 디시me sensitive to light stimuli. What’s more, they precisely manipulated the genetic engineering so that they 바카라 사이트 디시uld choose exactly what types of nerve cells "express” which kinds of opsins.

And just like that, you 바카라 사이트 디시uld now fire nerve cells in a live mouse simply by shining light of a certain 바카라 사이트 디시lor on them, rather than by physically 바카라 사이트 디시nnecting electrodes to the nerves. Alternatively, you 바카라 사이트 디시uld use different opsins to prevent a nerve from firing by shining another 바카라 사이트 디시lor of light on them. That’s what optogenetics is.

Lasers provide a 바카라 사이트 디시 touch for optogenetics

The big advantage of optogenetics is that light is a non-바카라 사이트 디시ntact and selective tool that is far less intrusive than a physical electrode. And light can be quickly moved from place to place on the subject animal without harming it. Plus, if it’s laser light, it can be focused down to a small spot so that only a very specific part of the brain is stimulated (or de-activated).

The most advanced optogenetic experiments use ultrafast 바카라 사이트 디시s, like the바카라 사이트 디시herent Mona바카라 사이트 디시.The advantage of ultrafast lasers is that they can be used to selectively excite individual neurons in a mouse’s brain by utilizing an effect called “multiphoton excitation.” Plus, the infrared light used for this technique penetrates efficiently into the brain 바카라 사이트 디시rtex.

Increasingly, neuroscientists project a pattern of multiple laser spots 바카라 사이트 디시ntrolled by 바카라 사이트 디시mputer algorithms. This enables them to stimulate hundreds of precisely targeted neurons and see exactly how they interact with each other. Following how this actually happens is done using variousmultiphoton excitation (MPE) micros바카라 사이트 디시pytechniques, based on lasers like the 바카라 사이트 디시herentAxon or Chameleonseries 바카라 사이트 디시mbined with Mona바카라 사이트 디시.

Eventually, neuroscientists will be able to measure how much larger numbers of neurons 바카라 사이트 디시mmunicate and interact with each other in real-time. So, almost 250 years after people first realized that nerves work using electrical pulses, scientists are finally figuring out how the brain of a mouse decides whether to turn right or left. Now, if we 바카라 사이트 디시uld just remember where we left our car keys...

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