14 September 2012

We Are All Cyborgs Now: Brain Implants that Think

A collaborative team of US scientists have developed a neural prosthesis which seems to exhibit the ability to restore lost cognitive functions -- and even to improve the function above the normal ability.

The study was performed in monkeys, but the findings will almost certainly apply to human brains, with the proper safeguards and modifications.

More from Technology Review:
The researchers used an array of electrodes to record the electrical activity of neurons in the prefrontal cortex of monkeys while they performed a memory task. The prefrontal cortex is involved in decision making and directs many types of cognitive responses associated with memory or other types of information processing.

The five monkeys in the study were trained to play a matching game in which they were shown an image on a screen and then had to use hand movements to steer a cursor to that same image out of two to seven others that they were shown anywhere from one to 90 seconds later.

...From their recordings in the prefrontal cortex, the research team extrapolated a mathematical model of the electrical activity of neurons involved in the movement decision. The study authors had previously shown that this kind of mathematical model, called MIMO—short for multi-input/multi-output—could interpret and replace memories in rats with the neural implant (see "A First Step Toward a Prosthesis for Memory").

In the new study, the model took multiple signals produced by the brain layer that integrates sensory information related to the task. It then extracted the relevant information to choose a particular movement. The implant can stimulate neurons in order to influence the decision to move the hand to select the correct image.

To test the implant's ability to improve or recover the decision process, the researchers gave the monkeys cocaine intravenously, since cocaine disrupts decision making. Without the activity of the implant, cocaine-affected monkeys frequently could not choose the correct image. But with the device, their decision making was on par, if not slightly better, than normal, even under the influence of cocaine. _TechnologyReview

This research represents the early stages of a neuroscientific campaign to gain the ability to replace damaged brain tissue after trauma, stroke, tumours, and abscesses -- as well as the ability to compensate for non-functioning and atrophied tissue from degenerative diseases such as Alzheimer's and Parkinson's.

It will be decades more before such prostheses are able to restore brain damaged persons to normal function -- or to convert normal brains into super-brains. But even marginal and incremental improvement can make a huge difference in the lives of those with brain impairment -- and in the lives of their families and caretakers.

Study Abstract

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