University of Washington researchers are working hard on an electronic chip that may help establish new nerve connections in the part of the brain that controls movement. This implantable chip strengthens weak connections and may rehabilitate patients with brain injuries, stroke, or paralysis.
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 study suggests that the brain"s nerve signals can be harnessed to create changes within it.
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 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 are turned off.