> We don't necessarily have to understand everything about the brain to communicate with it. And we'll learn a lot in the process. Very true! However, we're st

> We don't necessarily have to understand everything about the brain to communicate with it. And we'll learn a lot in the process. Very true! However, we're still learning a lot about the brain. For instance, astrocytes/glia are still quite understudied despite being ~1/2 of the cells in your brain (maybe). Mostly, this is because they are not very electrically reactive. But they are known to be a pathway for NMDAr recycling as well as surrounding the synapse in certain parts of the brain. This issue of astrocytes is one of thousands that we're still trying to get a grip on. Essentially, we have okay-ish knowledge of large-scale phenomena (~1cm3) and small-scale (synapse, nucleus) behavior, but the middle ground (10's of neurons) is quite hard. Unfortunately, that seems to be were all the magic happens. > A lot depends on how well the brain can adapt to a new form of I/O. Typically, it does this via scarring. Making sure the leads are engineered to deal with scarring is the first hurdle. Then you'd need to stimulate only a select few neurons, a feat that is quite difficult (dynamic positioning, heartbeat, discharges, feedback, etc). Not necessarily insurmountable problems, but we're not really sure how to do that compactly with wires. One way is just use light and optogenetics and CLARITY, but then you have to genetically modify a brain and wash it out in situ, which is downright crazy hard.