“Scientists have designed a brain implant that sharpened decision making and restored lost mental capacity in monkeys, providing the first demonstration in primates of the sort of brain prosthesis that could eventually help people with damage from dementia, strokes or other brain injuries.”
The device, though years away from commercial development, gives researchers a model for how to support and enhance fairly advanced mental skills in the frontal cortex of the brain, the seat of thinking and planning.The new report appeared on Thursday in the Journal of Neural Engineering.
”The whole idea is that the device would generate an output pattern that bypasses the damaged area, providing an alternative connection in the brain,” he said.
Many hurdles remain. Decision making, like memory, is a multifaceted process that involves many neural circuits, depending on the decision being made.
In the study, researchers at Wake Forest trained five rhesus monkeys to play a picture-matching game. The monkeys saw an image on a large screen – of a toy, a person, a mountain range – and tried to select the same image from a larger group of images that appeared on the same screen a little while later. The monkeys got a treat for every correct answer.
After two years of practice, the animals developed some mastery, getting about 75 per cent of the easier matches correct and 40 per cent of the harder ones, markedly better than chance guessing. The monkeys were implanted with a tiny probe with two sensors; it was threaded through the forehead and into two neighbouring layers of the cerebral cortex, the thin outer covering of the brain.
The two layers, called L-2/3 and L-5, are known to communicate with each other during decision making of the sort that the monkeys were doing when playing the matching game.
The device recorded the crackle of firing neurons during the animals’ choices and transmitted it to a computer. Researchers at USC, led by Theodore Berger, analysed this neural signal, and determined its pattern when the monkeys made correct choices.
To test the device, the team relayed this ”correct” signal into the monkeys’ brains when they were in the middle of choosing a possible picture match, and it improved their performance by about 10 per cent.
The technology used in the study could easily be contained on an implantable chip, Deadwyler said, and it is possible to envision a system that could help people with brain damage.