Sci is at SciAm today, talking about the latest “wastebook” a book released to point out “ridiculous” public spending, and which singled out many STEM projects this year, including one on cocaine…and risky sex habits in quail. At SciAm, I’ll talk about why we need these research projects, and why pointing it out in a “wastebook” isn’t going to change whether or not it is funded. Check it out!
After somewhat of a hiatus, the cranial nerves RETURN! After all, we can’t quit now! Only four more to go. And here’s where we’re at:
Oh: Optic and Optic 2
Virginia’s: Vestibulocochlear and Vestibulocochlear 2
So we’re up to cranial nerve IX, the Glossopharyngeal.
And for function:
Some Say Marry Money But My Brother Says Big Brains Matter Most.
Where the first letter of each word (they are all S, M, or B), corresponds with the functional role, where S is sensory, M is motor, and B is both. So you can see that the glossopharyndeal is going to have both sensory and motor fibers, which is going to make it that much more complicated.
But that’s ok. Repeat after me: Glossopharyngeal. Glossopharyngeal. Doesn’t it just SOUND nice? Like an onomatopoeia of what happens when a sip of delicious Coca-Cola Slurpee slips over the tongue and fizzes a little at the back.
And speaking of Slurpees…well what did you THINK the glossopharyngeal did?
Sci loves Portal. I think it’s a magnificently clever game, and Portal 2 is the in the same vein. I love the songs, I love the humor, and I love the concept (puzzle solving with a giant gun! That makes portals!), and I DESPERATELY want to play.
Sci, not unlike many people on this planet, is a sufferer of motion sickness. I’ve never been able to read in the car, and sitting in the back seat is often too much. Heck, sitting in the FRONT seat is sometimes bad! And Portal. Whooooo, Portal. Just WATCHING Portal makes me green in about 2 minutes, and attempting to play myself…well I only lasted about 30 seconds.
Motion sickness is caused by a mismatch between the perception of movement (say, moving in a car), and what your sense of balance perceives (that you’re sitting still). Finally the difference in perception causes dizziness and nausea. It’s stronger in some than in others, and for those of us who are really weak of stomach, well, we can thank an overactive vestibular system.
Last week we covered the basics of the auditory system, controlled by cranial nerve VIII, the vestibulocochlear nerve. But the “vestibulo” part of the vestibulocochlear nerve is, though in the same general location, something else entirely. Because cranial nerve VIII not only controls your hearing (the -cochlear part), it also controls your BALANCE and sense of how you’re moving through space. While this may seem to most people like it’s merely a matter of avoiding sharp objects and not embarrassing yourself on the dance floor, knowing your orientation in space is a universal issue for all living creatures. It’s something we don’t really think about, but are you facing up or down? Where is your head relative to your feet? When you’re moving forward, how do you know how FAST you’re going? These are all questions for your vestibular system.
And the vestibular system is OLD. All jawed vertebrates, you and the fish you just ate, and the chicken you had for dinner, pretty much have the same vestibular system setup.
You can the the cochlea sitting there, like a cute little snail, right where we covered it last time. Now, look just above it and slightly to the left. You see those two arches? Those are part of your semicircular canals. And those loops detect position and acceleration…and determine whether you’re feeling motion sick.
If you’ll excuse me, I’m feelin’ a bit queasy talking about all that acceleration…
Ok, I had a lot of fun writing about the Trigeminal. Making it all about a Bollywood movie makes EVERYTHING better. Unfortunately, Bollywood movies do not apply to everything (but they DO apply to most things).
So now, we move on to Cranial Nerve VII, the Facial nerve. Why, you say, WHERE was Cranial Nerve VI? I covered it with cranial nerve IV, actually, the trochlear and abducens together, since both innervate very similar muscles in the eye.
And so now we move onward to cranial nerve VII, the facial nerve. This is another mixed nerve, one that does BOTH sensory and motor functions. And being the facial nerve, it’s ALL about the FACE.
The question becomes: can I illustrate this ENTIRE post using nothing but pictures of different facial expressions?
(This is an example of an internet meme known as rage comics. They are user made and thus only sometimes funny, but i discovered them via this, which is both funny and horribly, horribly true. Basically, you have a limited number of faces, male or female, and you make comics out of them, and they all look a little like this guy. And I hope whoever invented them (I think it’s Reddit) doesn’t hurt me, cause I love Reddit. If you think these are funny, you can build them yourself, using the memebuilder, which is what I used for all of these).
You know, doing a series on the Cranial Nerves can get you down sometimes. I know this thing is going to be MAD useful for everyone (and may already be useful to many of you!) when it’s done. But right now, it’s “blah de blah nerve goes to the herp derp nucleus located in the blort de blort and innervates the doodads…”. It’s all a little formulaic and can get kind of…old. And Sci don’t DO old.
So I was reading all about the Trigeminal, and trying to think of a way to spice it up a little. And then it occurred to me. The trigeminal nerve and what it innervates can be ENTIRELY explained with the major plot points of a Bollywood movie.
If you don’t know what Bollywood is, well you’re missing out.
(Completely random time periods? Check. Highly suggestive moves without ANY KISSING EVAR? Check. Entirely random plot points? Check. Folks, we have BOLLYWOOD!)
Bollywood refers to a very specific kind of movie in the Hindi language, produced in India, and specific (often) to Mumbai. It’s got some very specific themes: Wildly incongruous, high energy song and dance numbers (Bollywood movies are ALWAYS musicals), highly melodramatic plot points (an evil villain tying a girl up on the train tracks is par for the course here), and the “almost kiss” which is about the sexiest thing you can get away with when making movies in India. And Bollywood…is wildly entertaining. Seriously. If you ever want to sit back with some popcorn and some seriously entertaining movies, I totally recommend Bollywood.
But melodrama. Let’s talk about melodrama. Because if there’s any nerve that does drama, it’s the trigeminal. Here we go.
Today we continue ONWARD with the series on the Cranial Nerves. But we’re doing something a little different. Because last time we covered the Oculomotor Nerve, which innervates FOUR of the SIX muscles which control the eye, today we’re going to round out the eye (heh, round, eye, heh) and do the other TWO. But we’re going to have to go out of order. The order of the Cranial Nerves (with convenient mnemonic!) goes like this:
We’ve been through the Oh, Oh, Oh (cranial nerves I, II, and III), but the two cranial nerves that control motor movements of the rest of the eye are NOT IV and V. Instead, they are IV and VI, the Trochlear Nerve and the Abducens. And we’re going to cover them together, because each one is a motor nerve that moves exactly one muscle, and each one sends signals out from exactly one nucleus. Nice and relatively simple.
So here we go. And we’ll start out seeing where they peek out from the brain:
You can see the trochlear nerve poking out, all thin, just to either side of the top of that rounded trapezoid that is the basal pons, while the abducens comes out of the bottom of the basal pons.
So I posted something the other day on bees and cell phones. The science in the paper itself wasn’t convincing to me, but the other references they pulled out in the discussion made me pull an about face. I thought, hey, maybe the electromagnetic field potentials from the cell phones ARE contributing to colony collapse disorder.
And thus I wrote my post.
And then came the morning, and Jonathan, on Twitter, who pointed out I was wrong (Credit to him and all the people at Ars Technica, for not only doing good writing, but for including links to papers at the end!!! WOO!!). And I looked, and asked, and then asked around.
I am TOTALLY F***ING WRONG, YOU GUYS.
I hate being wrong. I feel really dumb, and I feel like I’ve let you all down (all two of you who read the blog). I’m sorry, you guys. 🙁
(See? I maded an apology LOL)
SO. Like the good little scientist, I am going to revise my hypothesis. We’re going to cover this paper again, with MOAR references, and MOAR research. And I’m going to get it RIGHT. Or as right as I can under the circumstances.
Favre, D. “Mobile phone-induced honeybee worker piping” Apidologie, 2011.
(This dog in a bee suit, however, is NEVER wrong and way too cute. Source via Creative Commons)
IMPORTANT NOTE: Sci was too credulous when she wrote this post. I have since seen the error, written a correction, and the result is up here. PLEASE GO THERE for the real story on bees and cell phones. Thanks, y’all!
– a very ashamed Scicurious
Sci has been really interested in the latest literature on cell phones. Partially because some of it involves holding a cell phone over a petri dish filled with sperm, I will admit. 🙂 But it’s also just one of those things that really interest people. We’re using these super cool little gadgets that can access the internet anywhere…what ARE they doing to us? To our environments? Is it bad when you talk for a while and they get all warm and stuff? So I’ve begun digging through the lit. And just the other day, the brilliant and talented Desiree of Skeptically Speaking handed me this little gem.
It’s Official: Cell Phones are Killing Bees.
My first thought was…well KILLING seems an awfully strong word, especially if you’re not smashing a bee with your cell phone. So I had to read the paper. And now…I think I might be convinced.
Favre, D. “Mobile phone-induced honeybee worker piping” Apidologie, 2011.
So today we are taking a break from the cranial nerves (hey, I never said I would do them all straight through!) and delving into this. Everyone, put on your bee suits.
In the last few posts we’ve covered the first two cranial nerves, the Olfactory and the Optic nerves (remember our mnemonic: Oh, Oh, Oh, To Touch And Feel Virginia’s Gucci Vest, Ah Heaven). Both of these cranial nerves carry sensory information IN to the brain for processing, and don’t really control motion. For nerves like the olfactory, you wouldn’t expect much motion (can’t really move our nose around very well), but for the visual system, eye movements are extremely important, allowing you to focus the eye on the things that are most important in the visual field. Being able to do this accurately and at speed is extremely for complete processing of our visual field.
So today is for the third “Oh”, the oculomotor nerve. Move those eyeballs!
Last time we talked about the very basic anatomy of the eye. It was a lot of material. It’s too much. For you, I will sum up.
Light and images come through the cornea and hit the lens. The lens flips the image backward. The light continues to the back of the eye, often to your area of best focus called the fovea, where it filters through the layers of cells to hit your rods and cones. The rods and cones send signals to bipolar cells, which send signals to ganglion cells. The axons of the ganglion cells mass up at the back of eye and head off as your OPTIC NERVE!
Got it? Good. 🙂 If you want more, please head over to Monday’s post!
So, an image comes in. It will get flipped BACKWARD. It will hit the first cells LAST (the rods and cones are actually buried beneath several other layers). From here, we will go along to the back of the brain, and on the way the information will get flipped upside down. And then our brain processes it, and everything’s all right.
So, the image has come through. We’re past the lens, and everything is backward.