A self-powered, preprogrammable, constant current, electronic stimulator for implantation in conscious and...

A completely implantable electronic brain stimulator was designed and constructed using commercially available Complementary Metal Oxide Semiconductor digital, integrated circuits. All stimulation parameters were preprogrammed prior to implantation. They included bipolar pulse width (0.5 msec), constant current intensity (120 muA) and frequency (125 pulses/sec) as well as pulse train length (33 sec) and the interval between pulse trains (70 min). After complete encapsulation, the unit weighed 6.2 g and measured 30 mm X 15 mm X 8 mm. The units were easily implanted under the skin in the flank areas of 300 g rats. The 5 muW power consumption allowed implanted lifetimes of over 6 months. A miniature magnetic switch was included inside the package to allow testing of the unit after implantation. Stimulators were implanted in 17 rats for periods of 4--62 days in a study exploring the relationship between long term electrical stimulation of the lateral hypothalamus and the development of arterial pathology.