Micromachined probes for deep-brain stimulation

Although deep-brain stimulation (DBS) can be used to eliminate the severe side effects of Parkinson's disease (e.g., muscle tremors), it does not prevent neurodegeneration that leads to dementia or death. A combination of DBS and drug treatment might be capable of halting these degenerative processes by altering the response of neural tissue to drugs. In order to fully investigate this hypothesis, a comprehensive long-term stimulation study in an animal model is needed. We have designed, fabricated, and tested a novel micromachined probe that is able to accurately stimulate the subthalamic nucleus (STN) while minimizing damage to the surrounding tissue. The probe is coated with gold and insulated with silicon nitride for biocompatibility, has four platinum electrodes to provide a variety of stimulus patterns, and is formed in a novel 3-D plating process that results in a microwire-like geometry (i.e., smoothly tapering diameter) with a corresponding mechanically stable shank.