...or rather, the visual system. Cause you can't really talk about the optic nerve unless you talk about the rest of the eye along with it.
We humans rely pretty heavily on vision as a species. At least, being able to see is a lot more important to our daily lives than, say, being able to smell. But the visual system is, in many ways, surprisingly simple. In many OTHER ways, it's confusing as all get out. I will do my best. 🙂
So, I'm going to start with this: an image is going to come in. It will get flipped BACKWARD. It will hit the first cells LAST. It will then go along to the back of the brain, and on the way it will get flipped upside down. And then our brain processes it, and everything's all right. It's opposite day, my friends!!!
Today's is the first in a series of posts on the CRANIAL NERVES, the nerves that innervate a good chunk of your body, and which emerge DIRECTLY from your brain. We're going in order from the "front" of the brain, "brackward". So today's post is about the cranial nerve that's the closest to your face, the olfactory.
Take a nice, BIG sniff. What do you smell? Sci smells coffee, some nice spring air outside, car exhaust (ah, city living), my deodorant...you know, the basics. Whatever it is YOU smelled...well I hope it wasn't gross.
The reason you can smell what you're smelling is entirely due to the glory of your olfactory nerve. So today's post is, in a way, a salute to your nose. 'Cause it KNOWS.
(Used under Creative Commons, some rights reserved. Source)
I've been waiting for a while to take on another multi-part project (ok, I needed to recover from EB first), and now I think it is TIME. Time for a series SO LARGE that it's going to take me probably more than three weeks, or even four to finish (with breaks for Friday Weird Science, hey, I know what you're really here for). This is going to be INTENSE.
Today I would like to introduce you to the CRANIAL NERVES. When many people think of nerves, they tend to think of white, ropey kind of things which go down your hand. You know, like this:
The nerves that we tend to think of are bundles of neurons which extend from the central nervous system to provide impulses to, and receives sensory information from, various areas of our body. Most people think that these nerves extend exclusively from the spinal cord, and that all the impulses that you need travel up and down via the spinal cord. And these nerves certainly exist and you couldn't do a whole lot without them. But what a lot of people don't know is that a large portion of your body is innervated DIRECT from your brain, with nerves that we call the cranial nerves (because they emerge from, you know, the cranium). There are twelve of these cranial nerves, and over the next several weeks, you all will be getting a crash course in neuroanatomy as I go through them in detail, where they come from, where they go, what they are generally responsible for, and what happens when they are not working properly.
You can see the twelve cranial nerves listed in the photo above. Numbered 1-12, grad students in neuroscience and medical students in anatomy have to remember them all, as well as their characteristics (luckily for you, there will be no quiz at the end of this lesson!). To help in these we've contrived various mnemonics over the years. My favorites (the ones that aren't horribly dirty) are below.
Sci has been intending to do one of these posts for a while. I seem to spend ages talking about neurons, synapses, action potentials, connections, neurotransmitters, and different brain areas. But for all that, a lot of people don't really know what a neuron looks like and where the connections are taking place. So it's time to get back to basics. And that means a neuron (of course, things can get WAY more basic and in turn get more complicated, but we're sticking with the neurons for now).
And to help me out with this, I'm gonna take my first hack at Vuvox, a program allowing me to make an interactive collage. I saw Ed try it out to great effect for a post on ants as rafts (yes, AS rafts, it's awesome, go look), and I knew I HAD to try this one myself.
Here's what I've got:
The full text of the entry, with pictures in order and minus the popouts, is below. But it's much cooler up there, huh?
Welcome to...THE NEURON
Today's post is dedicated to Mr. S. My sad, sniffly Mr. S, who has welcomed the advent of spring with raucous sternutation. We don't understand it. There's no grass yet, the tree pollen is low. But the poor guy is a mess. And over the weekend, as his playing of Black Ops was continually interrupted by vigorous sneezes, we began to notice a certain amount of diurnal rhythm.
The mornings are the worst, no question. Dawn breaks out, and the tissues do too. He's full of gluey misery until about 11am or so, when things seem to generally quiet down. And then, then comes sundown, and the mucus flows most robustly until poor Mr. S finally passes out in a pile of used tissues. Don't worry, we've got antihistamine and lots of it, but it never gets rid of the symptoms entirely.
But being the scientist that I am, I noticed the pattern, he always seemed less miserable in the middle of the day. But the POLLEN can't be all that much better in the middle of the day, right? And at night, shouldn't it be better? But his allergies are worse! Is this normal? What does it MEAN?
I turned to the lit.
Nicholson and Bogie (a very appropriate name given the subject material...) "Diurnal variation in the
symptoms of hay fever: implications for pharmaceutical development" Current Medical Research and Opinion, 1973.
Perhaps some of you have heard of the fictional baby X (that's a PDF), a children's story piece which appeared in Ms. Magazine in 1975. I know that when I read it, I was amused, fascinated, and intrigued. The story is about a baby who is raised not as a girl, not as a boy, but as an X. The parents tell no one whether X is a boy or a girl, and many adventures ensue. I highly recommend you read the story, it's a fascinating reflection on what shapes us and forms us as boys and girls, beginning right at birth (and there is evidence of before birth shaping, too, but that's not what we're working on today).
Once you read the story of baby X, you might wonder, as I did, what the REAL effects of known gender have on how we deal with babies and young children. We might think we deal with babies fairly equally without regard to boy or girl, but...what DO we do? And more relevant to baby X, what do when do when we DON'T KNOW?
Welcome to the story of the REAL baby X.
(Is it a boy? Is it a girl? Is it a LOBSTER? It is ADORABLE. Source)
Seavey, Katz, and Zalk. "Baby X: The effect of gender labels on adult responses to infants" Sex roles, 1975.
I thought that I had wavy hair
Until I shaved. Instead,
I find that I have STRAIGHT hair
And a very wavy head.
The poem above is something I think of whenever I think of phrenology (also it's just awesome, because Shel Silverstein is always awesome). Phrenology was (and is!) a pseudoscientific practice that was most popular for about 30 years between 1810 and 1840. It's always held some interest for me, because it seems like the inventors got SO CLOSE to getting stuff RIGHT, and then they just veered off in the wrong direction and went off the deep end and took the express train to crazytown. And today's paper is one shining example.
"Comparison of the Skulls of Assassins and Men of Note" Science, 1885.
Sci is aware that the world freakin covered this paper last week. I don’t get access to press releases and so couldn’t get the paper until Friday, and well, time. But I really wanted to read it myself (yes, sometimes I read scientific papers for fun. What?!?!). And dang, this paper is COMPLETELY FASCINATING. I normally don’t say that about stuff outside my field. But WHOA.
Amoebas. They navigate mazes. They go from single, solitary little beings to huge conglomerates of cells in times of trouble. And now, they’re farming. Next, the WORLD. After all, they already figured out the transport system of Tokyo.
Brock, et al. “Primitive agriculture in a social amoeba” Nature, 2011.
The other night, Sci was drifting slowly off to sleep. Suddenly, I sneezed. It woke me up completely again, and left me wondering, with some irritation, whether it couldn't have waited til I was asleep and didn't care.
And then I thought: CAN you sneeze in your sleep? I asked the Twitterverse and looked around in vain. There are conflicting reports. I may not ever have my answer.
But dang did I ever learn a lot about sneezing. And of course, when that happens...I gotta blog it. So today's post is going to be a basic science post (SCIENCE! 101) on the SNEEZE. How it works, what causes it, and...whether you can do it in your sleep.
Songu and Cingi. "Sneeze reflex: facts and fiction" Therapeutic Advances in Respiratory Disease, 2009.
(Props go out to Songu and Cingi, who have written what may very well be one of the most entertaining reviews I have EVER read. I highly recommend).