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Posts tagged “biology

Day 326: Review: The state of spinal cord research

Figure 2 from and yet it moves
Figure 2 from and yet it moves

Facilitation of stepping-like volitional oscillations using non-invasive transcutaneous electrical spinal cord stimulation in SCI subject. (A) Position of the participant in the gravity-neutral apparatus. (B) Biphasic electrical stimulation was delivered using unique waveforms consisting of 0.3–1.0 ms bursts filled by 10 kHz frequency that were administered at 5–40 Hz. (C) EMG activity of right soleus (RSol), right tibialis anterior (RTA), right medial gastrocnemius (RMG), right hamstrings (RHam), right vastus lateralis (RVL), right rectus femoris (RRF) and angular displacement in the knee and hip joints of both legs during leg oscillations with a voluntary effort alone (Vol), stimulation at T11 (Stim), and Vol + Stim are shown. (D) Schematics demonstrating the approximate location of transcutaneous electrodes above the lumbosacral enlargement, in relation to the location of the motor pools based on Kendall et al. (1993) and Sharrard (1964).

Well it’s been two weeks (roughly) and my PI asked specifically that this week I do a review on the state of spinal cord research, with emphasis on the spinal cord stimulation work I’m doing. So this review is going to look slightly different, namely it has a rather long references section (15 total). If you find this research fascinating I recommend “And yet it moves” (reference 5). It’s long, but open access and worth the read. I’m a little bias though, my Co-PI is one of the authors. In any case, I had two weeks to write this, so hopefully it is a good dip into what we know about the spinal cord and a lot of what we don’t. Enjoy!

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Day 317: Mental health and you

neural symphony

I scream it loudly from the mountain tops, I suffer all the fucking time from mental health issues. I do it because staying silent doesn’t keep me from feeling them and it does nothing for others who are suffering. Yes, it’s embarrassing to talk about it because it feels like a taboo, or something you’re making up, but that’s why we need to talk about it and why you need to keep track of your own mental health.

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Day 316: Internships in the pandemic

Distance learning

For those of you not in academia, summertime means we get interns in the lab to learn about how research works in a real-life setting. We typically have them help with things that require basic skills, but lets them see how research really happens. This year, we are doing everything virtually thanks to COVID-19. This is a great thing because it really means we’re doing what we can to stop the spread while still giving students a chance to experience research.

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Day 315: Neural Engineering in a pandemic

pandemic PPE

For the past week or so my PI has been away, so I’ve had the chance to work on other projects from home. Unfortunately he returns this week so I’ve got to switch gears from protests, working from home, and undergrad mentoring back to experiments and experimental setup. As the senior student in the lab, I’ve got a lot of responsibilities.

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Day 310: Review – Interfacing with alpha motor neurons in spinal cord injury patients

Figure 1 from the paper showing EMG recordings and the transformation using deconvolution to motor neuron spike trains
Figure 1 from the paper showing EMG recordings and the transformation using deconvolution to motor neuron spike trains

Spatiotemporal spinal maps of ipsilateral a-MNs. (A) Experimental set-up for ankle plantar flexion. (B) HD-EMG is decomposed into a-MN spike trains using a convolutive blind-source separation technique. (C) The spinal output to generate the neural drive to muscles is estimated from the a-MN spike trains.

The world is on fire, we’re protesting for a future, but today I have my review paper due so instead of writing about my frustrations I’m going to share my review. Today we’re looking at the effects of trans-spinal direct current stimulation (tsDCS) on alpha motor neurons and how we can determine that effect using electromyography. It’s actually a very cool paper, the work is well done, and it’s open source so you can read it if you’re interested.

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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 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 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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Day 201: Know your spinal cord – The V-wave

spine

We’ve made it to day forty-three of our know your spinal cord series! While that is a lot of posts, we’ve made it super simple for you to find all of them with our neuroanatomy category. Lately, we’ve looked at several different tools in our spinal cord probing toolbox. We’ve seen all sorts of different ways to create a response, but we are still missing one important tool for our exploration into the unknown spinal cord world and that is what we are going to talk about today!

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Day 200: Know your spinal cord – Somatosensory evoked potentials

Somatosensory Evoked Potentials
Somatosensory Evoked Potentials

Somatosensory evoked potentials travel from peripheral nerves to the brain and we can record the response along the spinal cord and the brain non-invasively.

We’re back again with day forty-two of spinal cord knowledge series and day 200 in our 365 days of academia series! A friendly reminder that you can find each and every one of these posts in our very helpful neuroanatomy category. Yesterday we looked at motor evoked potentials, or electrical pulses that we create which travel from the brain to the muscles. Today we are looking at the almost reverse, signals we create originating in the peripheral nerves and arriving at the somatosensory cortex of the brain.

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Day 199: Know your spinal cord – Motor evoked potentials

Transcutaneous magnetic stimulation of the brain
Transcutaneous magnetic stimulation of the brain

Transcutaneous magnetic stimulation (left) stimulating a portion of the motor cortex, which travels down the spine and activates a muscle (right)

Day forty-one in the know your spinal cord series. While the number of posts is going up, we made them easy to find by using our awesome neuroanatomy category! Maybe we did this a bit backwards, but it’s our series and this was the order we did it in. Yesterday we covered cervicomedullary motor evoked potentials, which is a subset of what we will be covering today. So again, slightly out of order, but hey let’s look at motor evoked potentials.

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Day 198: Know your spinal cord – Cervicomedullary motor evoked potentials

Brainstem

Brainstem

We made it, day forty in the know your spinal cord series! I honestly didn’t think we would get this far into things, but here we are. As per usual, if you’re new you can find all of the posts in this series in our super helpful neuroanatomy category! For the rest of you, or the ones interested in this topic, today we are looking at yet another tool in uncovering the secrets of the spinal cord.

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Day 197: Know your spinal cord – The F-wave

H-reflex vs F-wave

It’s day thirty-nine of our know your spinal cord series and we’re only touching the surface (so to speak)! If you’re just joining us, then welcome! You can find all of our spinal cord knowledge in the handy neuroanatomy category. Well as these things typically happen, yesterday brought up an interesting gap in our knowledge base. While I introduced the H-reflex, we never talked about the F-wave! So of course yesterday’s post probably left some of you scratching your head as to what an F-wave even is, fear not we’re going to clear that up today!

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Day 195: Know your spinal cord – The spinotectal tract

Anterolateral-view-of-lumbar-spinal-cord

Welcome to day thirty-eight in the know your spinal cord series. As always, you can find the entire know your spinal cord series exclusively listed under our neuroanatomy category. We’ve amassed quite a bit of spinal information and I’ve gotten into more detail than I originally planned, which is part of the reason why we are going back and covering some of the things we skipped over. Today is one of those topics, we will be talking about the spinotectal tract, not to be confused with the tectospinal tract, which we already covered.

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