More on experimental prep
Since we have a rather large and cumbersome set of experiments happening it’s my job to make sure they go off without too much trouble. I say too much trouble because no matter how much you plan, test, and retest, something will go wrong. Heck it may not even be wrong on our end, it may be wrong on someone else’s side, but that’s why we plan. So once again I’m talking about how we prep for our experiments.
There are a lot of moving pieces to this experiment. In fact, it’s probably the most ambitious experiment we’ve tried and there are a lot of things we’re missing because the experiment is larger than we’ve ever tried to do. For the past week I’ve been furiously soldering parts together to get ready and I’m happy to say that everything is made… at least I hope it is! Since we’ve cleared that hurdle, it’s time to get the rest of the stuff ready.
Mostly experiment prep for electrophysiological research means setting up the sensors we will use to collect the data. Typically that’s not as easy as it sounds. There are a lot of cables, things running from one thing to another, stuff like that. In our case we have stuff that runs to an amplifier, that amplifier goes to, for lack of a better word the hub where all the data are sent to the computer to be stored. There are parts in between and parts before and after, but for a brief overview that sums it up pretty well.
Not always, but in our case, we have one wire per channel, per piece of equipment. With me so far? Good because we have 96 channels worth of data we’re collecting, and 3 “steps” the data take before going to to the computer and one wire for each step and each channel totalling roughly 288 individual connections, but who’s counting? Here’s where it gets fun, that doesn’t include ground, reference, or in some cases bipolar connections (meaning we double the wires for those bad boys, at the first step anyway).
All in all that’s a few hundred failure points and we haven’t even gotten to talk about software issues or the connections between the computer and our little hubs where the data get sent before storage on the computer. Thankfully all those channels aren’t being used by just us. No, because we don’t have room for that many channels worth of data. To be clear, since I don’t think I defined this and it may not be as obvious as I think, a channel is one individual measurement. It can be simple EMG (muscle recording), it can be EEG (brain recording), or just about anything else we can measure from breathing, heartbeat, eye blinks/movement, etc. And our setup doesn’t have that many channels so we’ve enlisted help from our collaborators on the experiment.
They will be supplying us with their own little setup to collect the data and we will be using additional equipment on our side to expand how much we can record. Which for those counting means we have three distinct systems collecting data. Which means we need a way to sync all that data. We can’t just hit one record button, we have to hit three, meaning no matter how well we time it, there will be a delay.
So we have yet another cable between all three systems that we use to generate what we call a sync pulse. The sync pulse is just what it sounds like, it sends a little pulse to each system at the exact same time to establish a point to align our data. That is a separate system so even more failure points (fun!), but generally speaking the equipment is reliable enough that we trust it, mostly. The fun part about research and using expensive, fancy, high accuracy, high tech, equipment is that it works incredibly well… until you do an experiment.
To help combat this well known and well documented phenomenon, we will be setting up the equipment beforehand and doing a dry run. I’ve basically assembled everything on our end already to go through and make sure our stuff is working properly (so far so good), so we will be setting up our joint equipment and testing all the connections/software/etc. to make sure it all plays nicely together and to help speed things up the day of the experiment. We can essentially set it up and forget it until the start of the experiment meaning we don’t waste precious time putting it all together again and running the risk of setting it up incorrectly.
There are a few teams we’re working with on this experiment, so we’ll need to coordinate well to make sure everything goes smoothly and we all have different things we want to try/do, but for the most part it’s our show since it was my idea that spurred the research. It’s a little scary, but I’m hopeful things will go well and hospital-PI had some good feedback regarding everything.
This isn’t my first time doing an experiment, nor is it the first time I’ve helped design an experiment, but it is the first time I’ve been the driving force for the experiment. It’s an odd feeling being on this side of the equation and not the do as I’m told side. I mean my dissertation is 110% my own little project, but that is, in my opinion anyway, vastly different from this.
Now with all the preparations being made, I’m hopeful that this will go off without too much trouble, but I fully expect to complain about it after the fact. So just know that if the next update is just a bunch of complaining, I knew it was coming!