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Archive for March, 2020

Day 225: Class presentations

Presentation

Presentation

For the past week we have been utilizing online resources so that classes can continue while we are all social distancing. While this is means that we mostly use Zoom, we also have message boards and other resources that we can use. However, these resources are sometimes a poor substitute for in person classes. This is especially apparent when we have certain assignments for the class, such as a group presentation.

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Day 224: Review – Cortical and Subcortical Effects of Transcutaneous Spinal Cord Stimulation

Figure 1 of the paper showing the experimental set-up and the type of pulse used for stimulation
Figure 1 of the paper showing the experimental set-up and the type of pulse used for stimulation

Experimental set-up. (A) Participants were comfortably seated in a customized chair during transcutaneous electrical spinal stimulation (TESS) or sham-TESS for 20 min. TESS was delivered using a surface electrode on the back of the neck between C5–C6 spinous processes segments (cathode) and a surface electrode in each anterior crest of the hip bone (anode) using a custom made 5 channel stimulator (BioStim5, Cozyma). Electrophysiological and behavioral outcomes were tested before (Pre) and immediately after, 15, 30, 45, 60 and 75 min after the end of the stimulation or sham stimulation period. (B) Schematic representation of the type of current used during TESS. We used 5 biphasic pulses at 5kHz with each biphasic pulse lasting for 200us. The middle scheme shows the blocks of 5 biphasic pulses passed at a 30Hz frequency. Lower part of the schematic shows the number of pulses delivered in one second.

Well it’s been two weeks since the last critical review so it’s that time again. As usual, my PI gets a copy and so do all of you. Since I’ve done several of these now (this is number six) I have a category just for these reviews called critical reviews. This is a really new study which tries to help tease apart what we are actually stimulating when we apply transcutaneous spinal stimulation. I think it’s a super interesting paper and I hope you do as well.

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Day 223: Hell is other people

From Dante's Inferno, a drawing of Lucifer in hell
From Dante's Inferno, a drawing of Lucifer in hell

15th century art impression of Dante’s Lucifer from Inferno

Sure, Sartre didn’t mean that hell is literally other people, that is a common misconception and therefore the quote is often misused. However, I’m misusing it on purpose because right now in my situation, hell really is other people. Did I mention that I hate group work? I really do and as a change of pace I’m going to try to explain without the tangents I tend to take because it’s going to be a fairly long story.

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Day 222: We’re still experimenting…?

Uncertainty

Yesterday we did science. It’s a weird feeling to be doing science when there is a pandemic going on, but I actually enjoyed it. There is something about being in a small(ish) windowless room and getting to tune out the rest of the world for a few hours. Yes, I said a few hours, experimenting takes time. Things are in flux though, even for me when I seem to have the most consistent schedule out of our lab.

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Day 221: Doing my part

My first print from way back when I got the 3D printer (a Lulzbot Taz 6).
My first print from way back when I got the 3D printer (a Lulzbot Taz 6).

My first print from way back when I got the 3D printer (a Lulzbot Taz 6).

Another day another update. I have to admit while the situation is fast changing it gives me something new to write about at least. Small victories maybe, I don’t know. The point is I was never one to sit around and let things happen. I’m a fairly busy person, between school and my fellowship I don’t get a lot of time to do things. Thankfully someone else with more time and/or resources has set up a way to help with the coronavirus supply shortage. (more…)


Day 220: Modeling the spread of COVID-19

covid19 map

Here’s the situation. We still have classes despite the county shuttering for a few weeks. I mean they are online classes, don’t panic, we’re using zoom like a lot of schools. However, it means that we still have class work and what not going on. For our last assignment we had to come up with our own problem to solve, then solve it. It wasn’t as easy as it sounds, but that is how I got this request (see the title of the post). Don’t worry I’ll explain. (more…)


Day 219: The county is on lockdown now

stay home limit travel save lives

stay home limit travel save lives

Finally. The county has asked that everyone shelter in place basically. Only go out if you need to go out. Everything is shut down and people seem to be taking this seriously (somewhat). While I am still pissed off about yesterday’s statements by the GOP, this is a good thing and I’ll take a win when we can get it. Unfortunately, there are some caveats to the lockdown and of course it affects me… (more…)


Day 218: You too are expendable

herd immunity

Well after yesterday’s post there has been a huge shift in rhetoric, so either the GOP reads my blog and thought it would be great to apply the same principle to America in general, or I just happened to guess right. I have to say, being okay with mass murdering a large portion of Americans seems like a bad idea, but clearly we have only the “smartest” people working in our government and not just the wealthiest… right?  For posterity’s sake let me explain since (I hope) 10 years from now someone reading this will have no clue what I’m referring to.

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The VA wants me dead, do you?

I swear I didn't kill anyone by the incredibly talented Lora Zombie.
I swear I didn't kill anyone by the incredibly talented Lora Zombie.

I swear I didn’t kill anyone by the incredibly talented Lora Zombie.

I hate writing about the VA, I really do. Unfortunately because I live here in the US where we think it’s our right to die from disease and have ludicrous amounts of medical debt for a sprained ankle, it’s a conversation we should have. Hello America, I served my country and now my country wants me dead. I sincerely wish I was exaggerating. Please hold your, “thank you for your service” for the end that way I can tell you to go fuck yourself. Let me explain…

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Day 216: So I’m “essential” now…

pandemic

Fun fact, I love pandemic movies. Movies, not so much living through one. As humans we are selfish, greedy, prone to panic, and for being “evolved” we are so very, very stupid. Basically every dumb choice you see the characters in those movies make while screaming, “you idiot, that would never happen in real life!” Well, it’s happening and wow does it do a number on a persons mental health. But hey guess what? I’m essential, so let’s figure out what that means in a time where the world is practically on fire.

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Day 215: What now?!

look ahead

Social distancing is important, but maybe not this distant…

Well if you missed it, yesterday was our final post in the know your spinal cord series. I’m not crying, you’re crying! Now the question is, what does that mean for the blog? An excellent question, one I wish I would’ve asked myself!  Let’s take a look at some of the things that we will (probably) be discussing now that our designated topic has run its course.

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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.

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Day 213: Know your spinal cord – Translating neural signals

whole brain and spinal cord dissected

whole brain and spinal cord dissected

Here we are on day fifty-three, we are nearing the end for sure. I was going to end the series today, but there is at least one more thing that I think will be interesting to cover. As always, you can find all of our posts in the neuroanatomy category, after all there are quite a few now. Today we are going to talk about how the brain and muscles use different signals to communicate. Basically, they speak different languages; let’s talk about what that means.

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Day 212: A small break

It was bound to happen, with the COVID-19 outbreak, my entire schedule has been shifting faster than I can keep up with it. I was going to force myself to write today, but I need a break. I’m exhausted both mentally and physically. There is a possibility I won’t be getting my stipend from the school this month, even though I’m still working, and I have assignments due soon, so I can’t dedicate the normal hour or so I would writing.

Friendly reminder, wash your hands, don’t touch your face, and practice social distancing. Even if you’re healthy, you can infect people that are not healthy or worse, people who work with others who are not healthy. Don’t be selfish! It may seem stupid now, but if we don’t do these things then it will get a lot worse and no one wants that. We can get through this if we all work together.


Day 211: Know your spinal cord – Transcutaneous spinal direct current stimulation

tsDSC simulation
tsDSC simulation

E amplitude distribution over the spinal cord and nerve surface. The color scale on the right is normalized with respect to the maximum of E amplitude in the spinal cord.

Well after our short break yesterday with my biweekly review paper, it’s back to the know your spinal cord series and we’re on day fifty-two! If you’re here for the first time, you can find the posts in this mini-series in the neuroanatomy category. We’ve taken a few twists and turns since we’ve started the series, but we’ve covered way more than I originally planned. We’ve covered how transcutaneous spinal cord stimulation is thought to work, that post focused on the type of spinal cord stimulation I’m researching. However, there are other ways to stimulate the cord. Transcutaneous spinal direct current stimulation (tsDCS) is a different way to stimulate and today we will talk about the difference.

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Day 210: Review – Cervical trans-spinal direct current stimulation: a modelling-experimental approach

Cervical trans-spinal direct current stimulation - Fig. 3
Cervical trans-spinal direct current stimulation - Fig. 3

Average magnitude of the E-field and average amplitude of its components in the spinal-WM in all montages along the z axis. Position of spinal segments is marked on the grey vertical bar, electrodes are represented by vertical bars and active connectors are marked with letter “A”. Volume plots of the E-field magnitude in cervico-thoracic spinal-WM, brainstem and cerebellum are represented at the right of the average distribution in each montage, with the corresponding colour scales

I lied! I did know what today was going to be on, it’s the fifth critical review paper. Since my PI gets a copy, so do you! To be honest, I need to create a category for these reviews (Update: I did make a category, Critical reviews), but for now, my first looking at elbow spinal stretch reflexes is here. My second where I review modulating spinal cord excitability with a static magnetic field here. The third where I review modulating the H-reflex while walking in spinal cord injury populations. Lastly, my fourth on Motoneuron excitability during voluntary muscle activity in a spinal cord injury population  can be found here. That said, let’s take a look at my latest review.

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Day 209: Know your spinal cord – Microglia

macrophage eating a bactria
macrophage eating a bactria

We cover this in the post, but it’s so cool I had to use it for the featured image.

It’s day fifty-one of knowing your spinal cord! For those of you who just found us, fear not we have all these posts in reverse chronological order listed in our neuroanatomy category. For everyone else, lately we’ve been talking about glial cells. This came about from the post on glial scarring which made me realize we should probably define glia. There are four types of glial cells found in the spinal cord (that we know of) we’ve covered three of them already and today we are talking about the last kind, the microglia.

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Day 208: Know your spinal cord – Ependymocytes

ependymal cells
ependymal cells

Ependymal cells, which create cerebral spinal fluid (CSF), line the ventricles of the brain and central canal of the spinal cord. These cells are cuboidal to columnar and have cilia and microvilli on their surfaces to circulate and absorb CSF.

We made it to yet another milestone, day fifty in our know your spinal cord series! As usual, you can find each and every one of these posts neatly organized in reverse chronological order using our neuroanatomy category. For the past couple of posts, we’ve introduced the types of glial cells, probably a bit poorly, but they are just so complex we can only really focus on a few of the functions. Needless to say they are very important cells. Today we are talking about the third (of four) types of glial cells found in the spinal cord (and brain), that is the ependymocyte. Let’s take a look.

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Day 207: Know your spinal cord – Astrocytes

upregulated spinal cord astrocytes
upregulated spinal cord astrocytes

SNL induces MCP-1 upregulation in spinal cord astrocytes (A–C)MCP-1 expression in the spinal cord of naïve animals (A) and SNL animals at 3 days (B) and 10 days (C). Scale bar, 200 μm. (D–F) High magnification images of (A–C), indicated in the white boxes of A–C, show the dorsal horn of the ipsilateral spinal cord. Scale bar, 100 μm. (G–I) Double staining shows that MCP-1 is colocalized with GFAP, a marker for astrocytes (G), but not with NeuN, a marker for neurons (H) or OX42, marker for microglia (I). Scale bar, 50 μm. DOI: 10.1523/JNEUROSCI.3623-08.2009

Day forty-nine in the spinal cord series! You can find all the posts in this series in our super useful neuroanatomy category. A couple of posts back we introduced glial scarring, one of the problems we need to overcome to help people with spinal cord injuries. That led to the realization that we needed to introduce the glial cells, so yesterday we covered the oligodendrocytes and today we are talking about the astrocyte. Now that we have some background of how we got here, let’s introduce today’s topic.

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Day 206: Know your spinal cord – Oligodendrocytes

Oligodendrocyte wrapped around axons of several nerves

Oligodendrocyte wrapped around axons of several nerves

We made it to day forty-eight! As always, the neuroanatomy category will help you find each and every post in the spinal cord series. It’s all really good stuff! We mentioned yesterday that this was coming, we’re going to do a quick breakdown of the types of glial cells just to make understanding the glial scarring post easier. Plus it helps to understand the functions of glial cells in general when we talk about things that could go wrong. With that, let’s get into oligodendrocytes!

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Day 205: Know your spinal cord – Glial scarring

Spinal cord regeneration
Spinal cord regeneration

Previously injured nerve fibers (red) are shown regrowing through a dense astrocyte scar (green). UCLA research shows that astrocyte scars actually help support nerve fiber regeneration. You can read more about the study from UCLA here.

Here we are at day forty-seven of spinal cord posts. We are definitely wrapping up our series sad to say, maybe we can get to day fifty, that would be a nice round number to stop at. For those of you who want to read all the other posts, the neuroanatomy category has everything in reverse chronological order and will teach you everything from the medullary pyramids, the cauda equina, and all the stuff in between. Today we are talking about glial scarring and why it’s such a problem a topic I realized we should touch on after talking about the problems with invasive spinal stimulation methods yesterday.

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Day 204: Know your spinal cord – Invasive stimulation techniques

paddle implant

It’s day forty-six in our spinal cord series. While we’re nearing the end (maybe), there are still a few things to cover. First, if you’re new, you can find all of the posts in the neuroanatomy category for when you need a quick spinal cord fix. I’ve been debating about this post for some time, but I figure we might as well cover it since we’re here. Today we are going to talk briefly about invasive spinal stimulation and what the future might hold.

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Day 203: Know your spinal cord – Compound action potentials

Action potential recording
Action potential recording

Image from: Get body smart

Day forty-five of the know your spinal cord series is here! With so many posts, you may be wondering how to find them all. Fear not, we have a super helpful neuroanatomy category for all your spinal cord needs. For the past few posts we’ve looked at some very interesting tools to probe the spinal cord. We’ve seen that there are quite a few ways we can go about it, but more importantly they all tell us something slightly different. Today we are looking at the product of that stimulation, the compound action potential.

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Day 202: Know your spinal cord – Transcutaneous Spinal Stimulation

TSS model

Welcome to day forty-four in the know your spinal cord series! As usual all of our posts are in a super easy to find neuroanatomy category. Now that we’ve covered our into into diagnostic tools to probe the spinal cord, let’s look at some of the ways we are working to help treat spinal cord injuries. Today we’re looking at a heavy hitter so to speak and something my research is focused on, transcutaneous spinal stimulation (TSS). Let’s take a look!

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