Cochlear Implants Prevent 'scrambling' In Deaf Brains

摘要

Brain activity that is "scrambled" in deaf cats develops normally if they are fitted with a cochlear implant shortly after birth. The finding may explain how deaf children given implants as babies can learn to speak almost as well as hearing children.rnIn hearing animals, sound vibrates hair cells in the inner ear, triggering neurons to send impulses to the brain. In deaf animals, these hair cells are often defective; cochlear implants compensate by stimulating neurons directly.rnTo see how this artificial stimulation affects the brain, Rob Shephard at the Bionic Ear Institute in Melbourne, Australia, and colleagues recorded electrical activity in the cortex of 178-month-old cats that were deaf from birth. As they monitored the cats' brains, they activated each cat's cochlear implant.rnTen of the cats had received the implant relatively recently and their electrical activity was "completely scrambled", indicating that they did not perceive sound coherently: normal cortex activityrnis key to perceiving sound and, in humans, to developing speech.