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

Area of Science:

• Neuroscience
• Biomedical Engineering
• Materials Science

Background:

• Long-term electrode implantation remains a significant hurdle for effective brain-computer interfaces (BCIs).
• Electrocorticography (ECoG) with flexible electrodes offers advantages over penetrative intracortical electrodes for chronic implantation.
• Developing stable, high-performance ECoG arrays is crucial for advancing BCI technology.

Purpose of the Study:

• To introduce a novel convex-shaped, hybrid polydimethylsiloxane (PDMS)-parylene multi-electrode array for stable, long-term ECoG recordings.
• To evaluate the performance of this new electrode array for neural recordings on the brain or spinal cord.
• To assess the array's ability to conform to curved biological surfaces like the brain.

Main Methods:

• Fabrication of a convex-shaped, PDMS-parylene hybrid multi-electrode array with 10 gold recording sites (100 μm diameter).
• Characterization of electrode impedance (50–70 kOhm at 1 kHz).
• Epidural ECoG recordings from the main olfactory bulb (MOB) of anesthetized rats during odor stimulation.

Main Results:

• The electrode array demonstrated stable ECoG recording capabilities.
• Odor stimulation successfully evoked responses in the MOB, evidenced by an increase in beta band power.
• The convex, octopus-leg-like design facilitated tight adherence to the ellipsoidal brain surface.

Conclusions:

• The proposed convex-shaped hybrid electrode array is a promising candidate for long-term, stable ECoG recordings.
• This technology could enhance the reliability and longevity of brain-computer interfaces.
• The design facilitates conformal contact, crucial for high-fidelity neural signal acquisition from curved brain structures.