Multichannel Silicon Probes for Awake Hippocampal Recordings in Large Animals

Area of Science:

• Neuroscience
• Biomedical Engineering

Background:

• Understanding cognition and memory requires decoding laminar information in deep brain structures.
• Large animal models are crucial for translational research due to similar neuroanatomy.
• A key limitation is the lack of suitable long-length probes for deep brain penetration in large animals.

Purpose of the Study:

• To evaluate the performance of novel multichannel silicon probes for large animal electrophysiology.
• To identify optimal probe designs for chronic implantation and recording in deep brain structures.

Main Methods:

• Tested various multichannel silicon probes in Yucatan pigs.
• Recorded neurophysiological signals (single units, local field potentials) from the dorsal hippocampus.
• Analyzed probe performance over time, focusing on signal quality and tissue damage.

Main Results:

• EDGE-style probes demonstrated the highest yield for intra-hippocampal recordings in pigs.
• Silicon probe cross-sectional area significantly impacted long-term performance, likely by reducing neural interface damage.
• Novel 64-channel EDGE-style probes showed optimal single unit separation and laminar structure sampling.

Conclusions:

• EDGE-style probes are suitable for chronic implantation and awake behavioral studies in large animals.
• Probe design, particularly cross-sectional area, is critical for sustained high-quality neural recordings.
• Current silicon probe designs are approaching the physical limits for achieving long-term, single-unit resolution in deep brain structures.