Researchers from University College London’s Sainsbury Wellcome Centre have devised a brain-machine interface (BMI) which allows mice to learn to move a cursor to a target using only their brain activity
This discovery could eventually be applied to improve BMI design. While BMIs have been under development for many decades, they still have limitations and are often invasive or time-consuming to learn to use.
“Brain machine interfaces are devices that allow a person or animal to control a computer with their mind,” said Dr Kelly Clancy, first author of the Neuron study. “In humans, that could be controlling a robotic arm to pick up a cup of water, or moving a cursor on a computer to type a message using the mind. In animals, we are using these devices as models for understanding how to make BMIs better.”
Sainsbury Wellcome Centre director Professor Tom Mrsic-Flogel added: “Right now, BMIs tend to be difficult for humans to use and it takes a long time to learn how to control a robotic arm, for example.”
“Once we understand the neural circuits supporting how intentional control is learned, which this work is starting to elucidate, we will hopefully be able to make it easier for people to use BMIs.”
Studying how causally-controlled objects are represented in the brain has proved a challenge, particularly due to the difficulty of discriminating between active control and passive observation. With BMIs, the subject does not physically move (no motor signals), meaning that a clearer comparison can be made.
In this study, the researchers used widefield brain imaging. This technique allowed them to look at the entire dorsal surface of the cortex while the animal was using the device – learning to control the cursor to a target to receive a reward and locate the areas involved in this process. They found that visual cortical areas were involved, including the parietal cortex: an area of the brain associated with intention in humans.
“Researchers have been studying the parietal cortex in humans for a long time. However, we weren’t necessarily expecting this area to pop out in our unbiased screen of the mouse brain,” said Clancy. “There seems to be something special about parietal cortex as it sits between sensory and motor areas in the brain and may act as a way station between them.”
The learning task in this mouse model – mapping their brain activity to sensory feedback – is analogous to how humans learn to interact with the world. Our brains build representations of how objects typically behave, and execute actions accordingly. Understanding how these rules are generated and updated in the brain could contribute to the development of human BMIs.