Electrical stimulation can boost brain's willingness to engage in mental effort

The bigger question is what you want to use it for. I think we've got a ways to go before we have "fire-and-forget" procedure work for everybody. Depending on where/how/when you stimulate, it's sometimes possible to produce the exact opposite of your intended effect. One of the headsets marketed for improving gaming had a big dust-up over that.

Are you interested in anything specific? Neuroscience is an absolutely massive field. At one end of my department, some folks are poking at the atomic structure of individual ion channels; at the other, people are looking at how social factors affect the brain and vice versa. It's hard to think of any one book that does it all justice.

On the other hand, there's been a flood of interesting books lately, so there's almost certainly something for you. Since you're on HN, you might like Grace Lindsay's Models of the Mind. It's about using math and physics to probe the brain, but it's a nice light read that focuses on analogies; no walls of impenetrable equations. If you like this, there are a ton of books that dive more deeply into the math to read next.

I've heard good things about Luiz Pessoa's The Entangled Brain, but haven't read it. It's more general neuroscience than focused on applications of math. People love Gyorgy Buzsaki's books Rhythms of the Brain and The Brain from Inside Out. I couldn't really get into them, in part because he was--loudly--wrong about the brain stim stuff in that article--but that's more of a personal beef.

If you want something more like a textbook, the standard is Kandel's Principles of Neural Science. It touches on almost everything, though often not in a particularly exciting or up-to-date way. It's not the worst book for a class, but it'd be a slog to power through in bed. Instead, I'd recommend Levitan and Kaczmarek's The Neuron: Cell and Molecular Biology. It covers a bit less (individual cells up through small neural networks), but I like the writing a lot more.

Another approach might be some hybrid science-biographies. These include Lessons from the Lobster, which is about Eve Marder and her work. The lobster stomach is a really fascinating circuit: seemingly simple, but capable of really complex behavior. The principles she worked out there have huge implications for more complex brains (like ours). Similarly, Brain and Visual Perception is about how David Hubel and Torsten Wiesel worked out some of the circuits in primary visual cortex--and won the Nobel Prize. I have not read Jill Bolte Taylor's My Stroke of Insight, but people seem to like it. It's about a brain anatomist realizing that she's having a stroke. Oliver Sacks' books are probably the standard bearer in this category. Some of the explanations are a bit dated, especially in The Man Who Mistook His Wife for a Hat (understandable, as it's from 1985), but the descriptions of the symptoms are fascinating.

Some anti-recommendations: I'd avoid Rodger Penrose's The Emperor's New Mind. It did get me interested in moving from CS to Neuro, but its explanations are, to put it EXTREMELY charitably, not very mainstream. Jeff Hawkin's book is not nearly as far out there, but his ideas also don't have a lot of traction. Stephen Grossberg's stuff is very polarizing: some ideas are very interesting, but also sometimes presented in ways that don't tie in well with the rest of the field, so I wouldn't start there.

That's a random walk through my reading list! If you're interested in a particular niche, let me know. There's also cool stuff about drugs, weird animals, sensation, etc...

The shocks you observe are caused by your body slightly grounding the conductive case. They are seen with any conductive case equipment used without grounding. Fortunately, they are not dangerous on doubly-insulated equipment like Macbooks.

I always assumed that was just because the surface has a strange microscopic pattern. I don't have one now, but I believe it only happens in one direction.

SignaGel is a conductive gel. It'll mostly stay in place and stays wet a lot longer than the sponges, but it is a little gross. Get it from a medical supplier rather than Amazon, where the individual tubes are massively overpriced. You might also be interested in 10-20 paste, which is a sticky conductive putty. It's a bit more expensive, but it stays put. Instead of the bands, you can also try a neoprene "swimcap" style holder.

Some of the tingling is unavoidable--the currents are driving fibers in the skin--but you can do a few things to reduce it. First, make sure there's good contact with the scalp: fully coat/saturate the electrodes and make sure they're pressed tight. The lower the impedance, the better. because the "dose" is specified in terms of current and you want to use as little voltage as possible to deliver that. Second, gradually ramp up the current instead of just switching it on/off. The sensation will diminish a bit over time anyway, so slowly increasing the current will make it more bearable. The difference between on/off and a 30 second ramp is really striking! We've used a topical anesthetic to block sensations, but it's a giant pain--it takes an hour to kick in and you need to tightly cover it too. Finally, be careful because you can burn the skin!

This is more of a side effect, which disappears over time. Relying on the euphoria of stimulants to get work done is a dead end, so be careful with this assumption.

That's a super cool activity, sounds so simple to manipulate your brain into the 'productive' behavior.