>Date: Fri, 5 Mar 1999 02:19:16 -0800 >To:Cynthia >From:[EMAIL PROTECTED] (Alex Constantine) >Subject:Brain Implants That Allow "Willful Thinking" > >Principles of Psychobiology >Interactive Study Guide for the Allied Neurosciences >[Visit Principles Home Page] >------------------------------------------------------------- >Short Feature Contents >Last Update: 02/21/99 > >Brain Implants That Allow "Willful Thinking" > > Neuroscientists have implanted a device in the motor neocortex of two >people that has allowed them to operate a computer display by "thinking" >about it. It has been known for many years that direct electrical >stimulation of particular brain regions can elicit sensory experiences, >memory recall, or motor responses. However, unlike scenes from many >(oftentimes bad) science fiction movies, it has always been unclear >whether or not brain cell activity could be used to control external >machines. > Dr. Phillip R. Kennedy, a researcher who has worked with researchers >at Georgia Institute of Technology and Emory University, developed an >implant that can be used to detect that activity of neurons, and convey >these signals to computers for further processing and control operations. >The small recording sensor is enclosed in a glass envelope and coated with >nerve growth factors that allow neurons in the region of the implant to >establish functional connections with the sensor. Normally, when >recording electrodes are implanted in brain tissue the region surrounding >the electrode is enveloped by glial cells (Module 1; Principles of >Psychobiology) that attempt to encapsulate the "foreign" material. This >electrically isolates the recording electrodes from small amplitude >potentials that are conveyed by individual axons, dendrites or gap >junctions (Modules 1-5; Principles of Psychobiology). The key development >is the application of nerve growth factors that apparently encourages the >growth of functional connections to the recording electrode -- This >formation of intact connections could be followed after implantation by a >change in the pattern of electrical activity detected by the electrode. > Surgeries on two patients were performed by Dr. Roy Bakay from Emory, >who presented the findings at the Congress of Neurological Surgeons annual >meeting in Seattle. The electrodes were implanted in the motor cortex, >near the arm/facial region (Module 7c; Principles of Psychobiology), and >signals were routed to a computer that moved a cursor across a screen to >an icon region. Both patients were paralyzed and unable to move their >limbs or speak. The first patient, who had the implant for 2.5 months >before dying from amyotrophic lateral sclerosis, learned to control the >signals in an "on-off manner" for seven days. The second patient (J.R.), >who suffered brain stem stroke after a heart attack, has had the implant >for 6 months. > Initially, this patient had a problem stopping his brain's electrical >activity, but researchers programmed a pause into the system so that >whenever the cursor landed on an icon, it stopped. Eventually, the patient >was able to stop the cursor at an icon and click it to say a word or a >phrase. > "This will hopefully open up a whole new world for J.R.," Bakay said. >"He is learning and so are we." > >More on this development from National Public Radio... >Click Here For NPR� Link (REAL AUDIO (tm) INTERVIEW) >
