The human brain contains on the order of X-hundred trillion synapses, making it one of the most complex systems known to man[sic].
Sensationalists love hooks like that. (I’m not going to lie though, I’ve used something like it myself.) However, to be more accurate, we should probably swap “one of the most complex systems known” for “one of the systems we are least likely to ever understand.” But that doesn’t mean we can’t try.
If we are ever to understand how the brain works, it will be through understanding its vast networks of connections. The brain contains many classes of connections, such as those between the cerebral hemispheres, or those between brain regions. But, if you go way down to the cellular level, you see connections between neurons called synapses, and that is where the magic actually happens. These synapses are the most basic connections through which information flows in the brain. Although there are probably other ways that the brain processes information, cell to cell communication through synapses (and its complexities) is currently the only one we have a substantial amount of evidence for and knowledge of.
We think information is processed not by single neurons passing info onward or back and forth, but by complex networks of neurons communicating with one another in specific spatial patterns (where a neuron is firing) and temporal patterns (when a neuron fires). A very basic example of a neural network is one we all know from the Dr.’s office: the knee-jerk reflex takes the neural signal produced in a sensory neuron by a tap to your knee, sends it up to your spinal cord, where the impulse is passed, via a synapse, to a motor neuron that then sends the impulse back down to your quadruceps and causes them to contract, resulting in a kick, or knee jerk.
This doesn’t involve much computation – you hit the patellar tendon, you get a knee jerk. It’s an all or none response, no halfway. But when you get up into the brain, where neurons have been known to have as many as 10 000 synapses on them, things get more complex.
In The Naive Observer I review new research about things like synapses, neural networks and connectomics. We know a fair bit about how synapses work, but as far as networks go, the work is largely descriptive, meaning that we are still working on seeing what the networks look like. So you won’t find much info on how any of these connections work to bring about things like memory, thought and emotion, because I don’t think we really know anything much about that. That’s not to say I won’t review lots of correlation and conjecture though.
I am a student and I always will be. Considering how much there is to know, I know essentially nothing and never will. The same goes for you. But you probably know more than I do, so please, when I am wrong, let me know – and don’t trust a word I say.