Sublime

Philosophical Foundations of Neuroscience, Bennett and Hacker

Why do we care about mTOR? Because this mechanism turns out to be one of the most important mediators of longevity at the cellular level. Not only that, but it is highly “conserved,”2 meaning it is found in virtually all forms of life, ranging from yeast to flies to worms and right on up to us humans. In biology, “conserved” means that something

self-replicating molecules known as DNA

Consciousness is still one of the great mysteries of science. A special 2005 issue of the journal Science ranked the top 125 open questions in science. The first-place winner was: What is the universe made of? A well-deserved win, given that today 96 percent of the matter and energy in the universe is “dark,” meaning “we’re in the dark about it.”

Neuromodulators are chemicals that fiddle with the settings of a neural circuit. They can turn the strength of connections between neurons up or down and make neurons fire more, less or in different patterns.

Evolution has pushed the nervous systems of insects toward minimalism and efficiency, cramming as much processing power as possible into small heads and bodies. Any extra mental ability—say, consciousness—requires more neurons, which would sap their already tight energy budget. They should pay that cost only if they reaped an important benefit.