Artificially connecting the activity of two brain sites can alter the motor function of freely behaving monkeys, according to a study published online in Nature. Associative plasticity - the classic theory that the paired activity of neurons underlies learning and memory in the brain - has, until now, been difficult to demonstrate in behaving animals.
Eberhard Fetz and colleagues implanted a 'Neurochip' into the brains of two adult monkeys (Macaca nemestrina), in an area of the primary motor cortex that controls wrist movement. They mapped the motor output of two sites within this area by observing the different wrist movements elicited when each of the sites was stimulated. A conditioning stage was then undertaken during which nerve impulses recorded at one site - referred to as Nrec - were used to trigger the delivery of an electrical stimulus to the other site - referred to as Nstim. The authors report that this changed the motor output of the first brain site, such that stimulating Nrec resulted in wrist movements similar to those observed following stimulation of Nstim.
The authors propose that their findings show that functional reorganization can be induced using neural activity at one site to trigger stimulation at another, thus creating an artificial connection. This represents a novel development for the field of brain-computer interface technology, and may have practical implications for rehabilitation after brain injury.
Eberhard Fetz (University of Washington, Seattle, WA, USA)
Abstract available online.
(C) Nature press release.
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