That Neuroscience Guy - Q&A: Pain, Mind Reading, and More

Episode Date: April 4, 2021

Am I Neurotypical? Does Artificial Intelligence really think like me? In the first That Neuroscience Guy Q&A, I answer your burning questions about neuroscience. 

Hi, my name is Olaf Krogolson, and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Today, it's Ask a Neuroscientist. People have emailed me questions or asked me questions in person, and you can too. I'll tell you how at the end of the episode. But what I'm going to do is answer your questions. So it's your chance to ask a neuroscientist. First question, do cells have their own central nervous system?

So in humans, the central nervous system is the brain and the spinal cord, So in humans, the central nervous system is the brain and the spinal cord, and the peripheral nervous system are effectively the nerves or neurons that run off of the central nervous system. In terms of a cell, or at least in terms of a neuron, there is a small central nervous system, and that is the nucleus of the cell, which is effectively the structure within the neuron that governs what it does. For the next question, how do we feel pain? Well, underneath your skin, you have a whole bunch of receptors. Those receptors are sensitive to touch, they're sensitive to temperature,

hot or cold, and you also have special pain receptors. So the way they work is essentially when that receptor is stimulated, then the neuron fires and that provides this sensation of pain. It also triggers some other responses. For instance, the emotional system might get involved and you experience pain, an unpleasant sensation that you want to avoid. You can imagine then, for instance, if these cells get damaged for some reason, you don't feel pain. You might have heard, for instance, that people that have frostbite, that's left permanent numbness in the foot, don't experience pain. That's because the pain receptors are effectively dead and the person doesn't experience pain. And the person then doesn't experience pain anymore.

Now, is this sensation the same for everybody? Well, not really. Pain is a learned experience in a sense, so we all experience pain slightly differently. And for instance, if you trained yourself to ignore some pain then you would be experiencing it different than another person and you can also look at it from the angle of individual differences in body state for instance a lot of people are hypersensitive to pain when they're extremely fatigued or tired and that's just your central nervous system it's sort of adjusting the the level of sensation that you experience So we don't all feel pain the same way.

Can you read someone's mind? Well, kind of. Using neuroimaging techniques such as functional magnetic resonance imaging or electroencephalography, we can get some idea of what a person is experiencing or thinking. But the technology is pretty blunt right now. With that being said, there's some really cool work coming out of some laboratories. For instance, there was a group over in Europe that put people in a fMRI scanner, and they showed them pictures of rooms that they'd been in and rooms that they had not been in. And that group was able to differentiate whether or not someone had been in the room before, based on the reaction of the brain to seeing the images. In another study done by another

research group, they showed people a series of objects. So imagine an apple, a fork, and a house, and they looked at the brain's response to those items. And then they used a computer algorithm to learn that pattern of neural activity. And then when that same person was shown those images again, the computer could decide whether the person was looking at a house or a apple or a fork. So in a sense, using neuroimaging technology, you can read someone's mind. whether the person was looking at a house or a apple or a fork. So in a sense, using neuroimaging technology, you can read someone's mind, but it's not quite as accurate as science fiction might portray it to be.

What is neurofeedback? Essentially, neurofeedback generally refers to a process where you read someone's current brain state, either using functional magnetic resonance imaging or EEG or functional near-infrared spectroscopy, and then you essentially show that information to them. So imagine you had an EEG system on your head. You could read in the brainwaves, and you could then show those brainwaves to a person and get them to attempt to adjust their brainwaves, for instance, by relaxing or by concentrating on something. And you've created a closed loop where you see your brainwaves, you do something to adjust your mental state, and then you see that change in your brain waves and

that's what neurofeedback is a lot of people say that neurofeedback can be beneficial to any number of different cognitive states the reality is the research on this is still not 100 clear but given the massive number of people that have reported positive experience from neurofeedback, it definitely needs to be investigated. Is a neural network or artificial intelligence actually performing as the human brain does? In principle, sort of. Typically, a neural network is an attempt on a computer using code to replicate, to some extent, the processing that goes on in the brain. So virtual neurons are created that are sensitive to input. And you could imagine, for instance, if you wanted to capture a photograph, you have an

input neuron for every pixel. And by activating a specific pattern you in a sense have represented the picture. Then there's typically a second layer of neurons which are called hidden neurons and this is where the math happens if you will. The input layer is processed through the hidden layer and that allows a classification. This is how your phone, for instance, recognizes your face relative to someone else. The input layer is the picture. The picture is processed through the hidden layer, virtual neurons,

and a classification decision is made. Now, this technology doesn't work right out of the box. You actually need to train the neural network so that it gets smart and it can recognize different pictures. But it does learn, and it does by simple feedback learning. You tell it when it's right or wrong, and it adjusts some parameters until it gets it right. And as these neural networks get more complex, they can do more incredible things. For instance, the Google DeepMind project plays Go, which is considered

to be one of the toughest games that you can learn to play. But always bear in mind that the Google DeepMind, while it can play Go, for instance, can't make you a pizza. So neural networks attempt to mirror the brain, and they do so in a limited extent in the way they function, but they're not quite the same as the human brain. Here's an interesting question. How many people are neurotypical? Well, there is no such thing as neurotypical. Let's take a different example. Let's think about this in terms of something like height. As you walk throughout the world, clearly you see that everyone has a different height, and if you factor in their weight as well, and the length and color of their hair, and any number of other factors, you'll see

that everyone is kind of unique. This is also true in the brain, in that our brains are all slightly different. Now, is there an average brain or an average state of brain function? Yes. But if you think of the word neurotypical in terms of something like Asperger's syndrome, for instance, that's a spectrum, and we all experience some aspects of that to some extent. It's just that some people experience these aspects more than others. So neurotypical is not really a thing. It's just an average, like the average height or average weight. And at the end of the day, we're all slightly different from each other. Following a stroke, what helps the brain create new pathways?

Following a stroke, what helps the brain create new pathways? Well, there's a lot of debate about how this works, but synaptic plasticity is a real thing, in the sense that throughout our lifespan, the brain can form new connections between existing neurons. So this is one of the mechanisms that we get new pathways following a stroke. As the brain adapts, new connections are made, and they're made basically by the neuron either actually growing and creating a new bridge, or by changing the strength of existing connections. And this is the second way in which the brain creates new pathways. The brain has existing connections that are present. Those connections might not be used as much as they would be prior to a stroke, for instance. And post-stroke, those connections are

activated. And following a stroke, we learn to use those connections that were previously not being used before. Kind of like driving a different route home. It might be a route that you don't normally take, but all of a sudden you decide to try a different pathway you haven't used before and it gets you to where you want to be. What is a phantom limb? Some people following a car crash or another tragic instance, report that the limb is still present. So the classic example would be someone that might have had their left arm amputated, yet they report that they can still feel their left arm. This is a phantom limb. The best theory that's been put forth was by Dr. Ramachandran, a famous neuroscientist, who suggested

that the phantom limb is still present because the body representation that we have. So within the primary sensory cortex and the related dissociation areas, the brain creates a representation of self or your body, and that representation still includes a left arm. And because of the way that the sensory neurons are organized, if a sensory area that's near the area that used to be used by the phantom limb is activated, then that causes activation of the sensory area that was previously used by the phantom limb. And you, in a sense, feel that the limb is still present. My name is Olof Kregolsen, and I'm That Neuroscience Guy. If you'd like to ask me a question, feel free to email me at thatneuroscienceguy at gmail.com, or post a question on my Twitter

feed at thatneurosciguy. Also, you can check out my website at www.olivkirgolson.com. Thanks for listening today, and I'll see you on the next episode.