Eric was right (aka Neurophysiology)

Eric was right. Quite a while ago (back when he was a fellow CA resident) I asked Eric what type of book I should read if I wanted to learn more about the brain. He told me that I was looking for stuff about the brain (the object), not the mind (thoughts - world of psychology) and that I should pick a particular sense and focus on it. He also gave me a few more clues on finding something I would find interesting. Well, I couldn't be satisfied by just picking one sense, I had to know about them all, and how neurons work, and about motion, and upper level thought, and basically all of neurophysiology and so I ended up reading the book Neurophysiology.

Holly crap that's a big topic. I had no idea. It's so big that I would say if someone wanted an introduction to it they should pick out one section to learn about... oh, wait, that sounds familiar.

I had been reading about cardiovascular physiology and that's a big topic, but wasn't terribly overwhelming. But after getting a bit into neurophysiology I realized that the eye, which may not be as complex as the heart, but is on a similar level, is one part of one sense and I realized how immense the topic is.

Before I go further - if you actually know something about the topic more than just reading one book feel free to jump in and correct any mistakes I make or add where I may have missed something.

Anyway, given that I did read the book I did learn a lot. I won't bother posting my page of equivalents between common electrical circuits and what is found in the body. One item I will comment on is that I knew that the body is very often a low pass filter (allows low frequency signals while stopping high frequency ones - a crude example is if you run your hand through a flame really fast it doesn't hurt as much as if you just leave it there - the body's low pass filtering also provides some leeway in how electric shocks are applied to it), but I didn't realize the amount of high pass filtering that is used in the body. The whole concept of adaption is high pass filtering (as you put on clothes you probably feel them, but once they are on you don't think about it - you've adapted to the feeling of them being there - you've high pass filtered the signal). This occurs in space as well as time by use of lateral inhibition - step into a really hot bath and you'll notice the feeling is really just the ring around where you are on the edge of being in the water. Also vision relies a lot of edge (or line) detection which is high pass filtering.

I also have to mention that the ear spatially performs a fourier transform - how cool is that!

One random fun fact about eyes. I had always had the impression that your pupils dilating and contracting is what controls the amount of light going into your eyes. Really it does make some difference, but not nearly enough to make up for the range of light that your eyes are able to deal with. What is really happening is that as your pupils contract they hide the more sensitive cells in your eyes, leaving only the cell that deal well with lots of light and as they dilate they expose the more light sensitive cells. The less sensitive cells are the ones that allow for color vision which is why color vision is better when there is more light. I feel like I've been lied to (or at least misled) by numerous science museums that all have that same exhibit with a light that shines in your eye and a mirror that lets you see your pupil adjust.

One sense I've always wondered about is smell. I never had a great idea how the other senses worked, but I had a general idea. But I had no idea how smell works - that's actually one of the reasons I wanted to read about more than one sense - I didn't want to just read about smell, but I wanted to know what's going on there. Well, I feel better now since it turns out no one really knows what's going on there. You're nose has a bunch of cells with a variety of molecule detectors, but how they all work together is a mystery. I really appreciate that the book was willing to admit when something is unknown - I think that's really missing from biology classes.

One thing that I've been realizing as I learn more about physiology is how much is going on inside cells. Perhaps I'm just revealing how little attention I paid in biology, but I had the impression that a cell is just a collection of some molecules (say 10 to 100). Clearly this is way off and a whole lot can go on inside a cell - catching on to that has really helped in understanding how biological systems can be so complex.

I guess I found it interesting and learned something because there are a number of things I would write about, but I should cut this off somewhere and if you're interested you can always read the book (or even better, take Eric's advice).