Wednesday, November 3, 2010

Controlling Visual Images

It may be possible someday for the Touchpad to be the Thought-Pad. New research at NIH shows that it is possible to manipulate complex visual images on a computer screen using only the mind. A study published in “Nature” found that when research subjects had their brains connected to a computer displaying two merged images, they could force the computer to display one of the images and discard the other. The signals transmitted from each subject’s brain to the computer were derived from just a handful of brain cells.

“The subjects were able to use their thoughts to override the images they saw on the computer screen”, said the study’s lead author, Itzhak Fried, M.D., PhD, a Professor of Neurosurgery at the University of California, Los Angeles.

The study shows progress in developing Brain-Computer Interfaces (BCI) devices allowing people to control computers or other devices with their thoughts. BCIs hold promise for helping paralyzed individuals to communicate or control prosthetic limbs. In the study, BCI technology was tested mostly as a tool to understand how the brain processes information and especially understand how thoughts and decisions are shaped by the collective activity of single brain cells.

The study involved 12 people with epilepsy who had fine wires implanted in their brains to record seizure activity to locate areas of the brain responsible for seizures. While the recordings from their brains were transmitted to a computer, the research subjects viewed two pictures superimposed on a computer screen, each picture showing a familiar object, place, animal, or person.

They were told to select one image as a target and to focus their thoughts on it until that image was fully visible and the other image faded away. The monitor was updated every one tenth of one second based on the input from the brain recordings. As a group, the subjects attempted this game nearly 900 times in total, and were able to force the monitor to display the target image in 70 percent of these attempts.

The brain recordings and the input to the computer were based on the activity of just four cells in the temporal lobe. Dr. Fried’s team first identified four brain cells with preferences for celebrities or familiar objects, animals, or landmarks, and then targeted the recording electrodes to those cells. The team found that when the subjects played the image switching game, their success appeared to depend on their ability to power up cells that preferred the target image and suppress cells that preferred the non-target image.

“This is a novel use of brain computer interface to explore how the brain directs attention and makes choices. The remarkable aspects of this study are that we can concentrate our attention to make a choice by modulating a few brain cells and control those cells very quickly,” said Debra Babcock, M.D., PhD, a Program Director at the National Institute of Neurological Disorders and Stroke that partly funded the study along with the National Institute of Mental Health.