The brain is really hard to see. The whole thing is very large - the human brain is several pounds in weight - but the connections between brain cells, known as synapses, are really tiny. They're nanoscale in dimension. So if you want to see how the cells of the brain are connected in networks, you have to see those connections, those synapses.
Edward BoydenWhen I'm talking to somebody, I'll put a piece of paper on the table and I'll write what I call a conversation summary - notes about the conversation on the piece of paper. At the end of the conversation, I'll take a picture on my phone and give the other person the original piece of paper.
Edward BoydenIf you give somebody a lot of questions to answer and then they walk by a bowl of candy, they are more likely to grab the candy because they're tired out from answering questions and can't resist.
Edward BoydenFor the last century of neuroscience, lots of people have tried to control neurons using all sorts of different technologies - pharmacology (drugs), electrical pulses, and so on. But none of these technologies are precise. With optogenetics, we can aim light at a single cell, or a set of cells, and turn just that set of cells on or off.
Edward BoydenIf you could map out a human brain, an open question is, if you simulated it, would it be you? Now, as we discussed earlier, we don't have a great definition or even a good technological handle to know whether something is conscious or not just by looking at it, so there's that aspect that we're not ready to answer, I would argue. But it raises very interesting questions about the nature of identity.
Edward Boyden