Electronic chip, interacting with the brain, modifies pathways for controlling movement

October 24, 2006

Researchers at the University of Washington (UW) are working on an implantable electronic chip that may help establish new nerve connections in the part of the brain that controls movement. Their most recent study, to be published in the Nov. 2, 2006, edition of Nature, showed such a device can induce brain changes in monkeys lasting more than a week. Strengthening of weak connections through this mechanism may have potential in the rehabilitation of patients with brain injuries, stroke, or paralysis.

The authors of study, titled "Long-Term Motor Cortex Plasticity Induced by an Electronic Neural Implant," were Dr. Andrew Jackson, senior research fellow in physiology and biophysics, Dr. Jaideep Mavoori, who recently earned a Ph.D. in electrical engineering from the UW, and Dr. Eberhard Fetz, professor of physiology and biophysics. For many years Fetz and his colleagues have studied how the brains of monkeys control their limb muscles.

When awake, the brain continuously governs the body's voluntary movements. This is largely done through the activity of nerve cells in the part of the brain called the motor cortex. These nerve cells, or neurons, send signals down to the spinal cord to control the contraction of certain muscles, like those in the arms and legs.

The possibility that these neural signals can be recorded directly and used to operate a computer or to control mechanical devices outside of the body has been driving the rapidly expanding field of brain-computer interfaces, often abbreviated BCI. The recent Nature study suggests that the brain's nerve signals can be harnessed to create changes within itself.

The researchers tested a miniature, self-contained device with a tiny computer chip. The devices were placed on top of the heads of monkeys who were free to carry out their usual behaviors, including sleep. Called a Neurochip, the brain-computer interface was developed by Mavoori for his doctoral thesis.

"The Neurochip records the activity of motor cortex cells," Fetz explained, "It can convert this activity into a stimulus that can be sent back to the brain, spinal cord, or muscle, and thereby set up an artificial connection that operates continuously during normal behavior. This recurrent brain-computer interface creates an artificial motor pathway that the brain may learn to use to compensate for impaired pathways."

Jackson found that, when the brain-computer interface continuously connects neighboring sites in the motor cortex, it produces long-lasting changes. Namely, the movements evoked from the recording site changed to resemble those evoked from the stimulation site.

The researchers said that a likely explanation for these changes is the strengthening of pathways within the cortex from the recording to the stimulation site. This strengthening may have been produced by the continuous synchronization of activity at the two sites, generated by the recurrent brain-computer interface.

Timing is critical for creating these connections, the researchers said. The conditioning effect occurs only if the delay between the recorded activity and the stimulation is brief enough. The changes are produced in a day of continuous conditioning with the recurrent brain-computer interface, but last for many days after the circuit is turned off.

"This unusually long-lasting plasticity may be related to the fact that the conditioning is associated with normal behavior," Fetz said.
-end-
The research was supported by grants from the National Institutes of Health, the Office of Naval Research, and the University of Washington Royalty Fund.

University of Washington

Related Spinal Cord Articles from Brightsurf:

Stem cells can help repair spinal cord after injury
Spinal cord injury often leads to permanent functional impairment. In a new study published in the journal Science researchers at Karolinska Institutet in Sweden show that it is possible to stimulate stem cells in the mouse spinal cord to form large amounts of new oligodendrocytes, cells that are essential to the ability of neurons to transmit signals, and thus to help repair the spinal cord after injury.

Improving treatment of spinal cord injuries
A group led by UC Riverside bioengineering professor Victor G.

Spinal cord gives bio-bots walking rhythm
Miniature biological robots are making greater strides than ever, thanks to the spinal cord directing their steps.

Co-delivery of IL-10 and NT-3 to enhance spinal cord injury repair
Spinal cord injury (SCI) creates a complex microenvironment that is not conducive to repair; growth factors are in short supply, whereas factors that inhibit regeneration are plentiful.

Locomotor engine in the spinal cord revealed
Researchers at Karolinska Institutet in Sweden have revealed a new principle of organization which explains how locomotion is coordinated in vertebrates akin to an engine with three gears.

Neurological signals from the spinal cord surprise scientists
With a study of the network between nerve and muscle cells in turtles, researchers from the University of Copenhagen have gained new insight into the way in which movements are generated and maintained.

An 'EpiPen' for spinal cord injuries
An injection of nanoparticles can prevent the body's immune system from overreacting to trauma, potentially preventing some spinal cord injuries from resulting in paralysis.

From spinal cord injury to recovery
Spinal cord injury disconnects communication between the brain and the spinal cord, disrupting control over part of the body.

Transplanting adult spinal cord tissues: A new strategy of repair spinal cord injury
Spinal cord injury repair is one of the most challenging medical problems, and no effective therapeutic methods has been developed.

Gene medication to help treat spinal cord injuries
The two-gene medication has been proven to recover motor functions in rats.

Read More: Spinal Cord News and Spinal Cord Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.