A convex-shaped, PDMS-parylene hybrid multichannel ECoG-electrode array.

Long-term electrode implant is a challenge for successful brain-computer interfaces (BCIs). It is well known that electrocorticography (ECoG) using flexible planar electrodes is more suitable for long-term implants than intracortical neural recordings using penetrative electrodes. In this study, we propose a convex-shaped, PDMS-parylene hybrid multi-electrode array for long-term stable ECoG recording on the brain or the spinal cord. The electrode array consists of 10 gold recording sites which show impedance values between 50 and 70 kOhm at 1 kHz with a diameter of 100 μm. It is designed like octopus's leg to tightly adhere to the ellipsoidal brain. To assess its performance, epidural ECoG recordings were performed from the main olfactory bulb (MOB) of an anesthetized rat during odor stimulation. The odor-evoked response was shown with an increase of the power in the beta band.