Micromanufactured electrodes for cortical field potential recording: in vivo study

摘要

Introduction: Electrodes able to perform high-resolution recordings with low interference and long term stable recording of cortical field potentials (CFP) have a wide medical applicability. The utilization of CFP was proposed as control signal for neuronal motor prostheses and epileptology. This study investigates the applicability of micromanufactured electrodes for subdural cortical recordings. Objective: To evaluate the applicability of subdural microelectrodes and study their signal quality across time. Method: A prototype of a grid array with eight platinum microelectrodes (320 urn diameter, arranged as a 2x4 grid with a pitch of 0.95mm) was developed based on laser- structuring of silicone rubber and precious metal foils. The electrodes were connected to a percutaneous plug which was encapsulated in silicone rubber. For the experiment eight adult Wistar rats underwent implantation. The animals were submitted to right parietal craniotomy. After the durotomy the grid was placed above the cortical surface guided by stereotaxic coordinates (aimed at the visual cortical area) and transoperative electrocorticography (ECoG) to ensure optimal contact. The bone flap was reinserted and the system was fixed to the skull with acrylic cement. After the recovering period the rats were taken to systematic bioimpedance measurements and ECoG recordings and the signal was analyzed with Spike2 and Matlab7.3. Results: The rats presented normal behavior during the recording sessions. The mean amplitude values were stable over a four weeks period. The impedances increased one week after implantation, but were then stable over a four week period. Conclusion: The use of micromanufactured electrodes may constitute a promising technique for chronic electrocorticographic recordings.