High-density, Identified Cell Recordings from Motor Cortex of Awake Behaving Macaques using 1024-channel SiNAPS-NHP...

Area of Science:

• Neuroscience
• Bioengineering
• Primate Research

Background:

• Acquiring bioelectric signals from numerous single neurons in primate brains is challenging.
• Chronic implants offer limited spatial sampling (~100 channels) from fixed cortical regions.
• Acute electrode insertion allows daily sampling from wider cortical areas.

Purpose of the Study:

• To develop an active dense CMOS probe for acute, large-scale single unit recordings in behaving monkeys.
• To establish experimental procedures for effective acute recordings in primate motor cortex.

Main Methods:

• A single-shank CMOS probe utilizing SiNAPS technology with multiplexing circuits was designed for macaque intracortical recordings.
• Multiple probe systems achieved synchronous sampling at 20 kHz/channel from over 2000 electrode-pixels.
• Procedures for multi-day insertions in behaving macaques and extraction of antidromically-identified neuron spiking times were developed.

Main Results:

• The probe features a 1024-electrode array (14 x 14 μm²) with 30 μm pitch, facilitating dural penetration via a pilot hole.
• Optimized insertion procedures enabled recordings from diverse cortical sites.
• Pyramidal tract neurons projecting to the spinal cord were identified via antidromic activation.

Conclusions:

• The developed probe configuration can access the anterior bank of the central sulcus.
• This region contains crucial corticospinal cells directly connecting to motoneurons.
• This work represents a significant advancement in primate neurophysiology tools.