You can imagine over very long timescales, perhaps far beyond the multi-decade time scale, we might be able to ask very deep questions about why we feel the way we feel about things, or why we think of ourselves in certain ways - questions that have been in the realm of psychology and philosophy but have been very difficult to get a firm mechanistic laws-of-physics grasp on.

I think the definition will change as we learn more, but my working definition of solving the brain is: one, we can model, maybe in a computer, the processes that generate things like thoughts and feelings, and two, we can understand how to cure brain disorders, like Alzheimer's and epilepsy. Those are my two driving goals. One is more human-condition oriented, and one more clinical.

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.

Unlike optogenetics, where there are existing nonprofits that give away the DNA for free or at cost, expansion microscopy requires chemicals to be used, so having a company that makes the chemistry kit that anybody can use can save time.

Work backward from your goal.

It's actually kind of weird that we can comprehend the law of gravity, or that we can understand quantum mechanics, enough at least to make computers.

For 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.