Monday, January 01, 2007

From the Labs: Biotechnology

New publications, experiments, and breakthroughs in biotechnology--and what they mean.

By Emily Singer

An implantable neurochip circuit board, hooked up to tiny wires, can be used to artificially connect two parts of the brain. Credit: A. Jackson, J. Mavoori, E. Fetz

Rerouting Brain Circuits with Implanted Chips
A chip being tested in monkeys could one day reconnect areas of a damaged brain

Source: "Long-Term Motor Cortex Plasticity Induced by an Electronic
Neural Implant"
Andrew Jackson et al.
Nature 444(7115): 56-60

RESULTS: Researchers from the University of Washington in Seattle showed for the first time in live animals that an implantable device could record signals from one part of the brain and transmit them to another part, reshaping neural connections in the process.

WHY IT MATTERS: In stroke and spinal­-cord injuries, neural circuits that mediate language or movement may be damaged, leaving patients with profound disabilities. The Washington research is a significant first step in developing neural prosthetics that can help bridge broken connections.

METHODS: Tiny wire electrodes were surgically implanted into a monkey's motor cortex. (Neurons in this area are active when an animal makes a voluntary movement.) The wires record the activity of nearby cells and relay their signals to a small printed circuit board for amplification and processing. The neural activity is converted to electric pulses, which stimulate cells at a neighboring motor-cortex site. The entire apparatus, about half the size of a deck of cards, is encased in titanium and attached to the monkey's head, where it doesn't interfere with the animal's normal daily activities.

NEXT STEPS: Project leader ­Eberhard Fetz and his colleagues hope to show that a similar device could transmit neural signals from the brain directly to the spinal cord or to a ­muscle, bypassing areas of neurological injury. The researchers have shown that electrically stimulating certain cells in the spinal cord can elicit specific movements, such as grasping.