Plastic neuronal probes for implantation in cortical and subcortical areas of the rat brain

We discuss the fabrication of flexible implantable probes for recording neuronal activity in the rat brain. We fabricated such probes bearing 12 platinum electrodes, using polyimide as a substrate and SU–8 as an insulation layer. The fabrication process was simplified through the use of laser ablation to define the probe outline. The probes showed not only good mechanical flexibility but also the required stiffness for implantation. Histology results and electrical recordings of neuronal activity lend support to the idea that the combination of polyimide and SU–8 represents a good choice of materials for the fabrication of implantable neuronal probes.