The work continues
Yesterday I mentioned all the work that was ahead for me. And work there is! While I have one dataset done (mostly) I need to process the rest of the data (ideally) to make my deadlines. Not all the data needs to be processed, but most of it would be nice, all of it would be great, and right now I have exactly no data processed so I am not exactly sure how much I’ll be able to finish today. Sometimes that’s just how these things go though.
(more…)Dissertation data update 1
I’m being lazy so we’re just going to number my updates with regards to the dissertation data I collected, because I’m tired and I can’t honestly think of a better way to do it at the moment. This is subject to change if I come up with a more creative way. So a while back I collected a bunch of data, then this weekend I had my first chance to teach the people who assisted the first steps to processing it. It turns out there’s a long way to go with them.
(more…)Effects of transcutaneous spinal cord stimulation on the brain
Transcutaneous spinal stimulation (TSS) is a relatively new approach to neuromodulation. We can activate networks in the spinal cord by injecting a small amount of current through the skin, which evokes a response in the muscles (muscle contraction). Depending on the person the electrical stimulus (the zappy time) feels either like a massage or it can be uncomfortable, not exactly painful, just not something you would go out of your way for. But the spinal cord is a two way street, so what does TSS do in the brain?
(more…)The value of clean data
In my line of research we have fancy algorithms to remove outside contamination to the data we collect. The problem with collecting electrophysiological data (electrical recordings from a person) is there is so much damned noise everywhere. The problem is magnified when you collect data that have a low signal to noise ratio (meaning lots of noise, not a lot of signal). Signal in this case is the thing we’re interested in measuring and while we have dozens of algorithms to filter (remove) the noise, there’s still no substitute for data that was well collected.
(more…)Real-time seizure state tracking
Since I shared one of the papers I was super proud of, I figure I can share the other one as well. Like the last paper (here) I’ll explain the concept and why this paper was important. I’ll also talk about why I think it was cool and where the idea came from. Mostly this post is for people who are interested in the work, but may not be familiar with the technical aspects so I’ll try to avoid technical terms or I will provide an explanation when needed.
(more…)Non-invasive study of the brain
Non-invasive research is difficult, especially when you’re working with something as complicated as the brain. Imagine being at a pro sports game outside the stadium and trying to figure out what’s going on inside just by listening. I’m constantly in awe that we can record activity from the brain without breaking the skin, it’s like magic. However, it’s still difficult and not without controversy.
(more…)Intro to ICA
Independent component analysis, probably not something you hear about all that often unless you’re in a field that uses it. If you’ve found this via google or the such, then you’re probably looking for an explanation on what the heck ICA is and how to use it. Fear not, today we’re going over the why of ICA, why it works, why we use it, and why it isn’t the perfect tool we wish it was. Hint, the reason it isn’t perfect is because of math, stupid math. Quick note, I’ll be focusing on EEG uses for ICA, but there are tons of other applications and this knowledge will still apply to them as well.
(more…)Learning can be painful
Well today was the final lab meeting of the term. While the weekly meetings will (probably) be continuing, it’s still a big deal and could (hopefully) mean the end of my six weeks or so of torment. Normally I give it a few days before I talk about just how badly the meeting went, but this time was different and I’m thankful for it. The difference? My main-PI was out for medical reasons, so we got to talk about the project a little more freely.
(more…)The long data processing road
Okay I’m taking another break from the “in statistics” posts, at least for today since the next topic is going to be a long multi-day post worth of stuff and I need an easier post for today. I have way too much stuff going on at the moment to organize a long post! In any case, I figure I could give an update to the data I’ve been working with and how that whole mess is going. It’s mind numbing and exhausting work, but not in the way you would think.
(more…)EEG cleaning progress
Yesterday’s coding work went better than expected! That may or may not bode will for the rest of the week, but hey at least I’m sort of ahead of schedule. Today I figure we can take a quick look at what I’ve been doing with the data and why. This will be part informative and part me complaining about how everything has to be so damned hard (basically the usual around here). Mostly it will just be some visuals of the things I’ve had to change to get everything looking like my main-PI wants, he’s got a particular style he likes so a lot of large text, bolded labels, etc.
(more…)An early present
Since my deadline has come and gone I can look around for a moment, but more importantly I don’t feel the pressure to hyperfocus on a single project. So today instead of working on that dataset I’m switching to a dataset I need to get done before my PhD proposal defense. It’s data that will (assuming I find something) further help make my case for studying my new “super secret” technique for the next 2-3 years depending on how long everything takes.
(more…)Back to EEG processing…
It’s the day after thanksgiving and I made my annual I don’t want to have to cook for the next week or two spread of tasty foods. I don’t do the traditional Thanksgiving foods though, I prefer Mexican dishes (since I’m Mexican). Namely I make a huge batch of tamales, since they are a bit of work I tend to make a comically large amount, think 100 or more. So while I have food to last, I need to get back to my main focus and that’s work!
(more…)How can we record from the brain non-invasively?
We can read your mind! Okay, not quite, we can read the electrical activity going on in the brain and we can do this non-invasively. That’s right, you can do it from your own home if you wanted (here). It’s easy and since you don’t have to break the skin, it’s about as safe as can be. The real question here is why does this even work? For that we need to talk a bit on biology so let’s do this!
(more…)EEG Cleaning: ICA and Dipoles
Let it be known that I’m a person of my word and today we’re going to give a rather broad overview of ICA and dipoles. Don’t know what those words mean? Well start here and that will give you a high level view of the entire process. Today we’re going to do a slightly deeper dive into what the heck a dipole is, why we use it for ICA and why ICA is so helpful in EEG data processing. Sound like a lot? Well it is, but let’s take a crack at it anyway!
(more…)How to process EEG data
For those just tuning in, I’ve been busy! I made my deadline, barely. Unfortunately that was one of two. The second requires me to have all the work done, not just part of it. I managed to finish one of ten (yes ten) of the datasets I had, so now I have less than two weeks to finish the rest of it Let’s take it from the top and discuss how we process EEG data!
(more…)EEG, not quite mind reading
Well I’m behind schedule and even though I was given an extra week (6 days now) I don’t know that I’m going to meet my deadline. It’s not me, it’s my computer, things take time to run so I’m stuck waiting for it to do its thing. Today let’s talk about what EEG is and how we make sense of it.
(more…)Into the unknown
Today is going to be a somewhat anxious day for me. It’s the day I get to crack open my data and see what spills out. There was a process to get to this point of course, it took me about a week, but today with just a few clicks I’m going to see if I have something or if my idea was never meant to be.
Read more… if you dare!Day 143: Meeting with my two PI’s
Some of our exoskeletons from the lab
Today was an interesting set of events. I had my meeting with my two PI’s (which I still think would make a hilarious television show). The meeting went well, I’m very excited, but I’m also getting ready to be very, VERY busy. Let’s breakdown how it went shall we?
Day 142: So you want to record from the brain…
My college helping me set up for the experiment I just did. This is how we add gel to the head, there is a tiny hole by each sensor, we then insert a blunt tip needle (we do NOT puncture the skin!) to add the gel between the sensor and the top of the head to eliminate the air gap caused by the hair. Unfortunately it looks scary, but we need something tiny to get around the sensor (if you look close you can seethe tiny, tiny opening each senor has). The lights on each sensor tell us how good of a connection we have, red means bad, yellow means we’re getting close, and green means good.
Today’s post was inspired by a conversation I was having yesterday in the comment section (you know who you are and thank you for the questions). I thought I would elaborate on how we record from the brain and why. There are a lot of different ways we can do this, some of them are super invasive and others are non-invasive. In the lab I work in now, we do things non-invasively there are good things about this and bad things about this, so let’s get into it!
Day 110: Experiment!
This is an actual photo from my experiment setup, one of my colleagues is adding gel to the sensors. While the giant syringe looks scary, it isn’t. It’s full of conductive gel that gets placed between the head and the sensor. There is no pain or puncturing of the skin involved. Afterwards the gel washes out of the hair. The real pain is sitting for ~30 minutes or so while we gel each electrode enough to get a good reading.
A few days ago I mentioned I did a thing, well an experimental thing really. It was… fun? It was definitely something. Overall it went well, but I said I would give everyone an update and I try to be a man of my word, so let’s do this.
Day 106: Super Busy!!!!!
Today I had my experiment (yay), so now I need to process the data. I also sat in another PhD defense for one of our lab members, so now that I have a free second I wanted to give an update. Expect a longer post tomorrow, but for today, I have sooooo much work to do!
Until next time, don’t stop learning!
Day 105: Defense day #1
This basically sums up today’s post…
Here we are another day another post. Today I will be spending the bulk of my time studying and getting my slides ready for the confrence I’ll be attending next week. That will be … fun? However today is also an important day for one of my fellow students, he’s defending his PhD.
Day 104: Experiment Prep
It looks like things are moving a little quicker than I thought for me. As you may or may not know, I’m getting ready to do an experiment. Well, we finally (finally!) finalized the protocol and just in time too. While I won’t make the deadline for my project update, I will have some data to show when we get to the conference, which is a good consolation prize.
Day 2: Power Spectral Density (pmtm)
A example EKG signal
This is a (somewhat) continuation on what we were discussing in the previous post. We covered the pwelch MATLAB function, this time we will cover the PMTM function, this function uses the Thomson multitaper method to calculate power spectral density. We can do a deep dive into the differences between the two next time, but for now let’s talk about the command itself.*
Day 1: Power Spectral Density (pwelch)
Some EEG data that I’ve aligned, processed, and made look nice and pretty.
Signal processing, it’s complex, there are a million ways to go about processing a signal, and like life, there is no best way to go about doing it. Trust me, it is as frustrating as it sounds. Today’s scratch pad note is on power spectral density or PSD for short. So let’s dive in.*
Lunatic Laboratories 