The second week of the course concentrated mainly on the astonishing world of action potentials and synapses. Chapter 4 – The action potential – was mostly familiar to me, except for the concepts of saltatory conduction and conduction velocity in general. I hadn’t even thought there are factors affecting the speed of action potential, so everything related to it was interesting.
In chapter 5 the principles of synaptic integration were also especially intriguing. So far the information about synapses and action potential has basically been about how the information is transmitted from cell to cell; now we got the first glimpse/molecular basis on how the inhibition of signals happens, and what are the mechanisms to control which signals are passed forward and which are not. Now it’s a bit easier to think the brain as an sophisticated algorithm; if some effect is inhibited, maybe this happens because the action potential has passed through a pathway (or an algorithm block) that has an inhibitory effect.
It was also interesting to learn the fact that dendrites don’t have ion channels. This I could nicely relate to the earlier learned fact that dendrites are short; if they were longer, they couldn’t conduct the depolarization. This also lead me to think, how much does the dendrite length affect on whether some information gets passed; are some dendrites longer because they are meant to pass the action potential only if the depolarization is strong enough?