'Virtual schizophrenia' could help scientists understand human brain
Scientists are using computers to develop a model that simulates what happens to cause brain dysfunction.
Researchers from the University of Texas at Austin and Yale University hope to learn more about the human brain by setting up a computer network that is a type of “virtual schizophrenia” that mimics dopamine release in the human brain.
Uli Grasemann, a graduate student in the Department of Computer Science at The University of Texas at Austin explains, “The hypothesis is that dopamine encodes the importance-the salience-of experience. When there’s too much dopamine, it leads to exaggerated salience, and the brain ends up learning from things that it shouldn’t be learning from.”
Grasemann and his adviser, Professor Risto Miikkulainen set up a computer network called DISCERN - Designed by Miikkulainen to learn natural language.
Computer mimics schizophrenic brain
Using simple stories, the researchers programmed the computer network to respond to words, phrases and other input in a consistent manner, mimicking the same process used by the human brain.
“With neural networks, you basically train them by showing them examples, over and over and over again,” says Grasemann. “Every time you show it an example, you say, if this is the input, then this should be your output, and if this is the input, then that should be your output. You do it again and again thousands of times, and every time it adjusts a little bit more towards doing what you want. In the end, if you do it enough, the network has learned.”
Next, the researchers increased the computer program’s learning rate. Grasemann said, “What we found is that if you crank up the learning rate in DISCERN high enough, it produces language abnormalities that suggest schizophrenia.”
The researchers found the computer memory broke down in ways similar to schizophrenia in humans. Grasemann says, in essence, the computer “derailed” from hyperlearning by jumbling information, dissociating and resorting to the “third-person” then back again.
“We have so much more control over neural networks than we could ever have over human subjects,” he says. “The hope is that this kind of modeling will help clinical research.”
Modeling the computer program to simulate what happens to humans to induce schizophrenia could give scientists more clues about what happens when excess dopamine is released in the human brain. The researchers say there is much to learn that perhaps can be gleaned from “virtual schizophrenia”.