As a child, Yvonne Visser (30) roamed every spring in the weekends across the Veluwe. Not to cycle or walk, but to help her father with his bird research. She climbed with a ladder against trees to nest boxes to see how many eggs there were. Together they gave the tits they caught a ring and determined the age.
Her father Marcel Visser investigated as an evolutionary ecologist how climate change disrupts the food chain of plants and animals. “If the oaks run earlier, caterpillars come into action earlier and are birds too late to find caterpillars for their youngsters.” In the meantime, he explained his daughter how to set up an experiment, what you should check for and how you do that. “That structured appealed to me enormously. And that his work came from things he wanted to know himself. That seemed great to me. “
A future in science was obvious, but in another field. “I wanted to do it on my own.” She did a Bachelor Psychobiology in Amsterdam and a Master Cognitive Neurosciences in Nijmegen, after which she worked as a research assistant in Paris for two years. “What interests me immensely is how it is possible that the brain works so well. We never think about that, but that is actually very special. “
Motor
This week Visser obtained his PhD at Radboud University in Nijmegen on fundamental research into decisions. “How do we process information from our environment, how do we make decisions and how do we prepare for action?” As an example in which these three aspects come together, Visser mentions a keeper in a football match that has to stop a penalty.
“The ball comes to you and you know that the ball will land left or right of you. Do you first decide that the ball goes to the left and then give your body the order to jump to the left? Or is it all happening at the same time? That is the basis of my research. ”
Despite the intuitive feeling that we first make a decision and only then act, earlier research shows that this is not the case. “While you make a decision, you are simultaneously preparing the different actions that are part of the decisions.” To stay with the example of the keeper; While it makes a trade -off, the muscles prepare to be able to go to the left and right. “The information on which the keeper bases his decision does not only remain in the visual processing and decision-making areas of the brain, but is constantly shared with the motor areas in your brain and the nerves that control your muscles,” Visser explains.
Moving dots on a screen
To imitate that situation in the lab, Visser showed test subjects moving dots on a screen and they had to indicate in which direction the dots moved.
Even before they determined that, Visser gave the upper arm a short push. “Because of that push, the muscle stretches for a moment and then moves together again to his previous state. In this way we measure how strong the muscle is prepared for a scenario to the left or to the right. If you want to go left, then the muscle must contract and if you want to the right, the muscle must stretch. ”
Because of that experiment, Visser could see that muscles are usually just a little more prepared for one action than the other. “It is not that you can no longer go to the other side, but in the muscles on which side the body is preparing more strongly. Even before the decision is made. ”
The same experiment shows that if someone decides to change direction, the muscles are less prepared for that movement. “If you are less convinced of yourself, you will see that in the muscles.”
Brain -controlled prostheses
Finally, Visser wanted to know how people react in an imminent situation. Specifically what they do in one Freezing State. “Compare it with a deer that sees a car coming off and stiffly stands still on the road. That is a very specific state of the body. ” The sympathetic nervous system, which is active in stress and activity, is very active. But the parasympathetic system, which ensures that the body can come to rest, also. “You will be stopped for a moment and you have to think about what is best to do.”
Visser simulated this state in its test subjects by giving them light electric shocks on their hand while the test subjects move to a suddenly appearing goal. “With the results we saw that the right direction has been more prepared under threat. It was already known that we then make better decisions, but that is therefore not only because of the cognitive decision, but also because you have better preparation in the muscle. ”
Just like her father, Visser is driven by curiosity. But if she still has to mention an application of her research, they are brain -controlled prostheses. “They often don’t work so well now, because we can’t read where someone wants to move. With research like mine, we are better able to understand how this goes naturally. As a result, we might let that prosthesis work better. ”