An implantation technique for polyimide based flexible array probes facilitating neuronavigation and chronic implantation

Flexible, polyimide based probes for chronic implantation provide a promising option for biocompatible neural interfaces minimizing foreign body response in the tissue and preventing electrode micromovements. Low mechanical stability is an issue for insertion of flexible probes. Solutions for precise intracerebral implantation are required to provide transient stability during insertion without obstructing functionality. We used flexible, polyimide based probes with lateral arrangement of recording and stimulation sites and a reinforced punch hole at the probe tip. Via the punch hole at the tip, the probe was mounted to a support rod and was then navigated to the insertion site. While the probe was lowered into the tissue, neuronal activity was recorded via the flexible probe in steps of 200 mu m. Characteristic multi-unit neuronal activity was recorded on the trajectory to the subthalamic nucleus. After insertion, the support rod was removed and neuronal activity was measured from the subthalamic nucleus in the awake and freely behaving animal. The reported implantation technique facilitates precise insertion while preserving probe functionality.