Thank you to to everyone who came to the Illinois Science Council’s Science Cocktail party!
As you may have noticed, because we thought the food, drinks,
music, raffle, and photo booth wouldn’t be enough, we provided you with a healthy dose of science as well. What would a science cocktail party be without it? In case you missed some of the demos, or if you want to learn more about the science behind them, you can read about each one here:
This game, called Mindflex Duel, is literally a battle of brains! The goal of the game is to push the ball to the other player’s side by concentrating the hardest. Sounds like science fiction? Perhaps it was a few years ago. But now, all it takes is an electroencephalograph (an EEG), which picks up your brain waves, and a motorized ball acts on the EEG’s signals.
How does it work?
The neurons in a player’s cortex (the wrinkled outer layer of the brain) send out small electrical signals that radiate through the scalp. The game’s headset has sensors that make contact with the forehead and can pick up on these small signals. This technology is called electroencephalography (ell – eck – tro – en – sef – o – la – grah – fee) electro = electricity, encephalo = in the head, graphy = writing). The EEGs that you are used to seeing on TV or in hospitals (like the one to the left) are much more complicated than the ones that are used in this game – they have a lot more sensors so that they can pick up a lot more information. With EEG technology, we can get an idea of what the cortex is doing at each millisecond. (That’s 1/1000th of a second!) Different cognitive activities produce different electrical signals (sometimes called “brainwaves”), and cognitive neuroscientists have figured out what a lot of thoughts and behaviors look like in the cortex by examining people’s brainwaves.
One way of looking at brainwaves is through frequency analysis. In other words, scientists look at how quickly electrical activity is fluctuating within the brain, or, the frequency of the brain waves. To the right are some different brainwave frequencies and the behaviors (in this case, states of arousal) that are associated with them. If you look at a continuous EEG recording like the one below, you can see some of these frequencies quite easily. In the example below, you can see some theta waves during an EEG session (using the full EEG cap pictured above). Looks like someone is getting sleepy!
Can you figure out, based on the schematic on the right, which kind of wave the game is looking for?
As you might have guessed, the game is looking for beta waves, which are brainwaves with a high frequency. This frequency indicates that the person is alert and concentrating. So, the EEG on your head noticed when your brain was emitting beta waves and took that to mean that you were concentrating on the ball, and therefore it moved it towards your opponent’s goal. Cool, right?
The Mirror Drawing Task
There are many areas of the brain involved in voluntary movements. One of these is the cerebellum, a leafy- looking structure at the base of the brain. The cerebellum’s main job is to guide the brain in learning procedural motor skills, such as riding a bike, painting, or playing a musical instrument. When first learning how to play the trumpet, for example, it’s likely you won’t spontaneously know where to put your fingers, much less be able to move them swiftly enough to play a tune. Instead, you’ll probably be a bit clumsy or unable to play at all. After a lot of practice though, your skills improve. Learning to play the trumpet (which requires procedural memory) is different from learning, say, all the state capitals (which requires semantic memory). You don’t develop procedural memories (and therefore motor skills) by reading books. Instead, you have to learn by doing. This is where the cerebellum comes in to help you. Once you have learned a new movement and your cerebellum gets the news, it places it in a permanent file, and every time you practice the movement, your cerebellum adds more information to that file (known as “muscle memory”). This is why you get better at motor tasks the more you practice them. It’s why you’ll never forget how to walk, talk, chew, or ride a bike.
The mirror drawing task is used to test impairments in procedural learning and memory. In this task, your job is to trace a star or some other shape. The trick is that you can’t look directly at your hand; you have to look at a mirror that is reflecting your hand and the paper you are drawing on. This reverses the image and makes it very difficult at first to trace the star. However, over time, your cerebellum, in coordination with your visual system, learns how to do it pretty well, just like how you learn to play the trumpet. This task was used to demonstrate the specificity of procedural memory in a famous neurosurgical patient known as H.M.
H.M. had a debilitating seizure disorder, and he underwent surgery to remove the brain region that was causing the seizures, which happened to be the region called the hippocampus. Fortunately, this stopped his intense seizures. However, it also had an unintended effect: he had anterograde amnesia, which means he could no longer retain memories of anything that happened after the surgery! If you met him one day, the next day he would have no idea who you were. In fact, you could meet him every single day for a year and he would never remember your face, your voice, or your name after you left. Surprisingly though, when doctors had him try out the mirror drawing task, he got better the more he practiced! This meant that while his ability to encode semantic memories (like facts) was gone, he was still able to form procedural memories. In fact, whenever they had H.M. complete this task, they had to teach him how to do it every single time, yet once he started, he was better at it than the last time he did it. This was one of the first pieces of evidence that our memory is broken down into different systems. One system supports learning things like names and state capitals (semantic memory), and another system supports learning an instrument or learning how to draw a start by looking in a mirror (procedural memory).
Want to learn about the other demos from the party? Check out part II here!
Will Beischel is a graduate student in psychology at the University of Michigan.