Interactive fNIRS Signal Simulator: Hemodynamics, Beer-Lambert Law & BCIs | BioniChaos

Yeah, we're going to be reviewing this new tool. It's uh fNIRS simulation functional near-infrared spectroscopy. It's a synthetic signal generator, essentially. Everything we do is available on body kills.com. Go check out the website. There's more than 200 tools, spectrograms, generators, and data processing, signal processing, and medical data viewers, BCI brain computer interfaces, simulators, EMG hand simulation tool. Some fun things as well, like drawing, uh music generator. Check it out as well. So, it's currently playing, so you can just do the drawing, it will turn it into into music. So, you can play multiple streams at the same time. Change your major minor scale. Yes, you get I think you get the picture. Let me know if you tried it out, if it's any if it's useful for you or not. Actually, have another one if you're already on it. This is more of a possible to get in a double touch on on a touch screen. >> Yes, it's full a full-fledged musical instrument cuz you can change your harmonic keys. Yes, you go check it out as well. But currently we'll focus on this F knees simulator. I will put it in full screen. Yes, there's a description at the bottom of the page. I'll put it in full screen. So, you can play with yourself. And this demo mode will actually play a demonstration as well, like a visual. It actually show what the controller is doing and what this simulation tool is capable of. And we have this overview by a notebook. It's not notebook 11 anymore. I don't know what it's called. A Gemini notebook. Yes, so we'll listen to it while the the page itself will be in demo mode changing parameters and things so you can see how to use it and what you can do with it. >> If you break your arm, an X-ray gives you like a jagged white line. It says structural, binary, and honestly comforting because we can clearly see the hardware. >> It's very straightforward. >> Yeah, but today we're looking at the software. We are looking at a way to literally watch the brain think in real time just by shining a beam of light through the skull. Welcome to this deep dive. >> It's such an amazing concept. >> is. Today we're exploring the interactive simulation tool over at bionikaios.com pronounced bionic chaos. Our mission is to act as your audio guide to this optical neuroimaging simulator. >> Exactly. >> So, if you're running the application's automated demo mode right now, just sit back and watch the canvas as we decode what you are actually seeing. >> And it's an incredibly detailed model you're looking at. On that main canvas, the most prominent features are, well, those two moving lines undulating across the screen. >> and blue ones. >> Yeah, exactly. The red line represents oxygenated hemoglobin, and the blue line is for deoxygenated hemoglobin. >> I know this is simulating fNIRS, or functional near-infrared spectroscopy, but before we get into the specific controls on the dashboard, how does shining a light at a head give us, you know, two distinct measurements of blood? >> So, it all comes down to the modified Beer-Lambert law. >> Okay. >> This law describes how light travels through a scattering medium like human tissue. So, near-infrared light actually passes safely through the scalp and skull. >> Just right through the bone? >> Yeah, right through. But, the crucial part is what happens when it hits your blood. Oxygenated and deoxygenated hemoglobin actually absorb different wavelengths of near-infrared light at different rates. >> Oh, wow. >> So, by measuring the specific light that bounces back to the sensors, the tool calculates exactly how much fresh blood is present in that area. >> Let me make sure I have this mechanism right. It's almost like a microscopic traffic report. >> That is a really good way to put it, yeah. >> Like a region of the cortex works hard, demands energy, and then triggers a massive delivery of fresh oxygen-rich blood, right? And that surge registers as our red line. Then that rush of fresh blood physically washes away the old deoxygenated traffic, which causes the blue line to dip. >> You nailed it. That dynamic is called neurovascular coupling. >> Neurovascular coupling? >> Yeah. It as the physiological signature of actual cognitive effort. It basically separates true brain activity from just like random physiological noise. >> Wait, if we are measuring blood flow, isn't there a delay? I mean, blood doesn't move at the speed of an electrical thought. >> Good catch. Yeah, there is. The vascular response actually peaks a few seconds after the initial neural firing. >> Makes sense. >> So, it's a proxy for brain activity rather than a direct electrical measurement, but it provides highly localized and really reliable spatial data. >> Okay, that makes total sense. And as the demo mode runs for you all listening, you'll notice it interacting with the control panel on the right. You can actually manipulate the entire 300 second session. >> Yeah, like toggling specific optode channel pairs to isolate different physical source detector geometries on the head. >> Which is super cool. Like, when it selects pairs like FP1-F3 and FP2-F4, it's actually isolating the left and right sides of the prefrontal cortex. >> Exactly. And the vital takeaway on the canvas there is the resulting bilateral symmetry. >> Right. You see the blood flow for both regions moving in tandem. >> Yeah, proving that both hemispheres are teaming up to handle the mental workload. >> You can also speed up the playback, too. >> Right, absolutely. Scrubbing through it two or five times speed makes those vascular peaks much easier to spot visually. >> Totally. Another layer to this is the hemodynamic sonification toggle. When you turn the audio on, the web tool translates the subtle amplitudes of the red oxygenated blood flow into pitch shifts. >> Yeah, shifting between 100 and 800 hertz, it literally turns the vascular data into a real-time acoustic symphony. >> It sounds wild. >> It really does. But, it's important to clarify that this entire setup isn't just, you know, a clever visualization trick. The synthetic data engine driving this simulation is actually modeling real-world interference. >> Interference like, uh, motion artifacts from someone just moving their head around. >> Sometimes, yeah, but also much deeper physiological noise. The simulation specifically includes Mayer waves. >> Wait, Mayer waves? >> Yeah, they are natural systemic blood pressure fluctuations that occur around 0.1 hertz. >> Oh, wow. So, it's that detailed. >> Very. In real clinical data, Mayer waves can easily mask the subtle brain signals you're actually trying to extract. So, this tool forces researchers to confront that messy reality. >> So, it's like a training ground. >> Exactly. It's designed to prep developers for the Bionic Cloud SDK where they'll be tasked with integrating real wearable brain computer interfaces. >> So, you train here on the simulator to prepare for the live noisy data coming from actual human heads. That is incredible. >> It is a massive step for developers, for sure. >> It really is. And that brings up a larger implication for you to consider as you watch those red and blue waves roll by. If a simple web application can map the hidden blood flow of our cognitive effort and translate it into visible charts and audible tones, how long until we use these exact real-time feedback loops to consciously rewire how our own brains process focus, stress, or even joy? >> Okay, so that was a noble lamb. Good over stay. Improve that demo mode. It should have showcased more things. Like adding different and removing up to channel pairs. Uh scrolling fast and slow. So, we have oxygenation, deoxygenation and deoxygenation. You can choose which one you want to see. Yeah, that's pretty much keep it keep it simple like like that. And do let me know if you tried it. If you have any questions, comments, anything we can improve, do let me know. Could perhaps simulate a real task of actually do like a cognitive task. So, it matches the activity of brain in brain. The blood oxygen oxygenation deoxygenation is actually matches the the cognitive task uh synthetic patient is doing. Yes, you can check this tool on the bodycal.com/fNIRS. Check out all the other tools we have. And I'll see you next time.