So I spent today playing with human brains. The first time you hold someone’s loves, hopes and fears between your hands is really quite a numinous moment. It is just amazing to reflect that a person’s entire memory, their desires and hates, their quirks and oddities, are all written as a pattern of neural connections onto that orange-sized chunk of porridgy stuff. It makes me remember why I’m here, that in spite of how heavy and difficult the work load is, I really am in the privileged position of learning how our biology, our brains, our behavior, really works.
Just thought I’d like to share…
Batteries power the clock in your living room. Sunlight powers the one in your brain—or at least keeps it accurate. That jet lag you feel when you step off a plane after an epic trip is caused by a brain clock, or circadian rhythm, out of sync with the world. Therefore, the best thing you can do after such a trip? Is go out into the sunlight, and stay in it long enough for the sun and the brain clock to synchronize.
Sunlight is absorbed by special cells in the eye called intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells do not need the rods and cones in the eye responsible for vision. Instead, they contain the pigment melanopsin that absorbs the sunlight directly. The ipRGCs then project to the superchiasmatic nucleus (SCN), which contains the “clock cells.” Levels of PER and CRY proteins in these cells increase and decrease on a regular time schedule, marking the 24 hours of the day (more or less), and tell the brain what time it is. [If you want more detail on that, let me know. It’s pretty amazing].
At least, that’s the classic model.
But what’s this? New research is saying that we don’t need the ipRGCs for our circadian rhythms either. The rods and cones of the retina can do a fine job setting the brain clock without these special melanopsin-containing cells. Surprisingly, The retina seems to have a rhythm of its own! In fact, if you take a retina, put it in a petri dish, and then sync it to light, you can sync the clock of SCN cells by just plopping them into the same petri dish! No projections necessary!
Somehow, the retina is sending out signals that can synchronize the SCN. What it is sending out? Hormones? Neurotransmitters? Magic powers? No one knows.
For now, though, it might be best to just keep syncing with sunlight. >_<
I’m Facebook chatting with a former student because her stupid college Psychology textbook uses analogies to explain stuff before even posting a diagram of a concept and explaining it in a straightforward, scientific manner. I understand that American people are achieving less and less academically as the years go by, but maybe it has something to do with the fact that we need to have our hands held because our seemingly feeble minds can’t handle straight-up science.
Seriously, this book, which I’m looking at right now online, decides to explain action potentials of the neuron with a baseball stadium analogy before even attempting to show a picture of what’s going on with the scientific explanation written out. And the analogy isn’t even very good because a baseball stadium is generally circular in shape. I can see this actually confusing some of the students even more.
This is why I barely use a textbook with my Psychology students. We’ll refer to it here and there in class when certain diagrams need to be looked at. But I would much rather have them make connections to the real world while outside of the classroom after having had the core concepts explained and discussed together at school (via many, many custom handouts that I’ve made over the years).
Learning is about connecting new ideas to ones that you already know, and making sure that these connections are meaningful is the best way to help people learn those things for life. That’s why analogies are helpful. But they better be good ones that don’t break down with the tiniest bit of scrutiny. And teachers need to remember that some people learn best when information is presented confidently, clearly, and in the most straightforward manner. You can’t ignore the tendencies of the more “traditional” learners (I know, that’s a loaded term) to only satisfy the needs of the ones who learn very differently. Lately, I see a strong trend towards meeting the needs of that latter group at the expense of the former.
It’s all about balance. But in order to do that, teachers need to be balanced, well-rounded individuals who can think in many different modes and empathize with all types of teenagers. Maybe that should be our first goal.
All I can think off is the chemistry popular science book that likened the electrons in the respiratory chain to a stolen handbag being passed along a line of criminals. There was not a single chemical formula or cell schematic in this book and these analogies just made the whole thing even more confusing!
This post is a worthwhile read.