Studying Medicine

Neurosciences 371: Pretty Darn Cool

Today I feel lazy and not in the mood to study, even though I have a big test next Friday. I felt so lazy that I actually got up and made some Rice Crispie cakes; and then proceeded to eat them all. All in the name of not studying. I feel quite ill, if that is any consolation.

Rice Crispy Treats, image from wix.com

Anyway, in an effort to feel like I have done some revision today, I figured I’d go over the reasons I think Neurosciences are, to use a 90s expression, the bomb.

Not only is the department super organised and put a lot of effort into teaching, but it is also SUPER interesting. That’s a lot from somebody who, for the most part, found second year to be a drag.

Ever bumped your toe and instinctively curled up in a little ball clutching it as though it might fall off? There is a very nice physiological reason for that. In the afferent part of our peripheral nervous system, there are stimulatory neurons and inhibitory neurons. The activation of certain neurons on one little spot of toe can have an inhibitory effect on the neuron in another little spot of the toe. Thus, while pain may be the stimulus, applying pressure in a nearby spot activates an inhibitory neuron, which ACTUALLY lessens the pain.

That sounds way more complicated than it did in my mind and I now cannot find a nice picture for it on Google.

It gets more interesting. Why does it hurt when you touch an open wound? That sounds like a stupid question right, like DUH, it’s an open wound, of course it will hurt. But what about a bruise? Or a torn ligament? We possess over something called wide dynamic range cells. These are specific receptors that only work once activated by pain. In other words, they sense pain only once initially activated by pain. Pain = more pain. In essence, they lower the pain threshold, which is why you are then more sensitive to modalities that may previously not have hurt.

“Seeing stars” is also not just a metaphor. Every sensory receptor in your body is made to register only a specific stimulus. This is called “label line coding” and explains why you can’t hear with your fingers (lip reading doesn’t count). The rods and cones in your retina are only made to register vision, and so any energy applied to it will be interpreted as a visual pattern.

Many of us know that a particular smell can awaken emotions much easier than say, a view or a melody. This is thought to be because the olfactory sense is the only sense that isn’t first routed through a part of the brain called the thalamus. The sense of smell passes directly to the cerebral cortex.

We also do some ophthalmology. A lot, actually, and I find it quite interesting. Quick, tilt your head to the side.

Can you still read this? It doesn’t appear skew?

That’s because of some pretty cool muscles of ocular motility, the superior and inferior obliques. It is their job to keep your eyes gazing level even when your head is tilted.

Also, it seems that the image projected to your brain by your eyes is actually a pretty fuzzy, pixelated and rudimentary image. Our brains fill the missing gaps to create the clear image we see. Now I think – and this is purely a theory and I have NO EVIDENCE WHATSOEVER – that maybe that is the reason we view different things, different people even, as being attractive. Maybe? Maybe because we actually SEE them differently. Just a thought. A pretty clever evolutionary trick if you ask me.

So I think neuro or ophthal are pretty cool. Who knows… it might just be my thing…

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