Posted by Ken | Posted in TED Conference, Videos | Posted on 22-11-2011
Ed Boyden At the MIT Media Lab, Ed Boyden leads the Synthetic Neurobiology Group, which invents technologies to reveal how cognition and emotion arise from brain networks
Ed Boyden shows how, by inserting genes for light-sensitive proteins into brain cells, he can selectively activate or de-activate specific neurons with fiber-optic implants. With this unprecedented level of control, he’s managed to cure mice of analogs of PTSD and certain forms of blindness. On the horizon: neural prosthetics.
Think about your day for a second. You woke up, felt fresh air on your face as you walked out the door, encountered new colleagues and had great discussions, and felt at awe when you found something new. But I bet there’s something you didn’t think about today – something so close to home that you probably don’t think about it very often at all. And that’s that all the sensations, feelings, decisions and actions are mediated by the computer in your head called the brain.
Now the brain may not look like much from the outside – a couple pounds of pinkish-gray flesh,amorphous – but the last hundred years of neuroscience have allowed us to zoom in on the brain, and to see the intricacy of what lies within.And they’ve told us that this brain is an incredibly complicated circuit made out of hundreds of billions of cells called neurons. Now unlike a human-designed computer, where there’s a fairly small number of different parts – we know how they work, because we humans designed them –the brain is made out of thousands of different kinds of cells, maybe tens of thousands. They come in different shapes; they’re made out of different molecules; and they project and connect to different brain regions. And they also change different ways in different disease states.
Let’s make it concrete. There’s a class of cells, a fairly small cell, an inhibitory cell, that quiets its neighbors. It’s one of the cells that seems to be atrophied in orders like schizophrenia. It’s called the basket cell. And this cell is one of the thousands of kinds of cell that we are learning about. New ones are being discovered everyday.As just a second example: these pyramidal cells, large cells, they can span a significant fraction of the brain. They’re excitatory. And these are some of the cells that might be overactive in disorders such as epilepsy. Every one of these cells is an incredible electrical device. They receive input from thousands of upstream partners and compute their own electrical outputs, which then, if they pass a certain threshold, will go to thousands of downstream partners. And this process, which takes just a millisecond or so, happens thousands of times a minute in every one of your 100 billion cells, as long as you live and think and feel.
So how are we going to figure out what this circuit does? Ideally, we could go through the circuit and turn these different kinds of cell on and off and see whether we could figure out which ones contribute to certain functions and which ones go wrong in certain pathologies. If we could activate cells, we could see what powers they can unleash, what they can initiate and sustain. If we could turn them off, then we could try and figure out what they’re necessary for. And that’s a story I’m going to tell you about today. And honestly, where we’ve gone through over the last 11 years, through an attempt to find ways of turning circuits and cells and parts and pathways of the brain on and off, both to understand the science, and also to confront some of the issues that face us all as humans. ………… this is part of the script from his talk at TED. How to get over fear & a lot more. http://www.ted.com/talks/ed_boyden.html