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Day 214: Know your spinal cord – The Recap

motor neuron histology

It’s day fifty-four and we’ve hit the end of our journey for this mini-series. For one last time, you can find all our posts in the neuroanatomy category. Everything comes to an end eventually and today I think we should do a small wrap up. This isn’t just a repeat of everything we went over though, we’re going to attempt to tie a lot of the topics together. So let’s give this a shot.

Over the past fifty-four days, we’ve covered a lot. We’ve learned that the spinal cord has a lot of different functions, from reflexes to playing translator for the brain and muscles. The spinal cord is far more than just a freeway for information, it processes data independently of the brain! But let’s take it from the top!

 

brainstem

The spinal cord technically starts after the medullary pyramids (shown above). It’s organized into several tracts, like the corticospinal tract. While the brain and the spine are made up of the same grey and white matter, unlike the brain, the grey matter is on the inside and the white matter is on the outside. The grey matter forms a “butterfly” shape and we can see a good image of that below.

dorsal root ganglion

We talked about different ways we can “poke” the circuitry of the spinal cord to see how it responds. One of the main ways we do this in my lab is by using the H-reflex, which tells us a lot about how the spinal circuitry works without actually seeing the reaction from the spinal cord directly (since we can’t record the signals from the spinal cord directly). While electrical stimulation gives us a very repeatable way to test, we can also perturb limbs to study reflexes, which was one of my favorite studies I’ve reviewed becuase of how thoroughly they tested.

We also learned quite a bit about the state of spinal cord injury rehabilitation. Unfortunately there isn’t a lot we can do (right now) to help people dealing with spinal cord injury. While rehabilitation is our first line of defense, our lab does spinal cord stimulation to help pre activate spinal motoneuron networks. This preactivation means the neurons fire more easily. Because spinal cord injury typically interferes with signaling and thus reducing the amplitude of signal, we can restore some function by reducing the threshold for firing with some pretty amazing results (like the video below, which to me is incredible).

We also took a look at the glial cells and the glial scar that forms after trauma to the cord. Depending on who you ask, the glial scar is a good thing that helps recovery or is something that hinders it. To be fair, it’s probably a combination of both helping and hindering. Ultimately, being able to regenerate the spinal cord would be the best way to recover from a spinal cord injury. However, until we can accomplish that, spinal cord stimulation seems to be one of the best interventions for spinal cord injury we have right now.

Overall it’s been a fun series and I hope that you’ve learned a lot. We’ve covered so much over the past almost eight weeks that it’s just crazy to think we’ve made it to the end! Since this was a very high level overview of everything, it may be worth going back and getting into even more detail. For now, we’re going to close this mini-series and while it’s sad for sure, it was a lot of fun for me. Thanks for following along and I hope I’ve inspired some of you to join the field!

Until next time, don’t stop learning! 

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