Custom-designed high-density conformal planar multielectrode arrays for brain slice electrophysiology

Area of Science:

• Neuroscience
• Bioengineering
• Electrophysiology

Background:

• Multielectrode arrays (MEAs) advance electrophysiology, but planar MEAs (pMEAs) face spatial resolution vs. recording area trade-offs.
• Existing pMEAs limit exploration of complex spatio-temporal dynamics in neural circuits.

Purpose of the Study:

• To develop custom, experiment-specific, tissue-conformal high-density pMEAs (cMEAs) to overcome limitations of traditional MEAs.
• To demonstrate the utility of cMEAs for precise stimulation and recording in acute hippocampal slices.

Main Methods:

• Designed and fabricated four configurations of cMEAs with high electrode density (50-60 µm spacing) on glass substrates.
• Utilized photolithography, ITO leads, silicon nitride and SU-8 insulation, and gold/platinum electrode coatings.
• Conformed cMEA designs to hippocampal slice cytoarchitecture for targeted stimulation and recording.

Main Results:

• Successfully recorded monosynaptic, disynaptic, and trisynaptic field potentials, demonstrating cMEA stimulation and recording capabilities.
• Conformal designs enabled optimal electrode placement for stimulating specific afferent pathways (e.g., Schaffer collaterals, perforant path).
• High-density arrays facilitated detailed current source density (CSD) analysis of laminar profiles in the CA1 region.

Conclusions:

• Custom-designed cMEAs effectively address the spatial resolution and recording area limitations of traditional pMEAs.
• cMEAs provide high spatial resolution for selective neural pathway stimulation and advanced electrophysiological analysis like CSD.
• These novel cMEAs enhance the ability to investigate complex neural dynamics in brain slices.