Thin flexible arrays for long-term multi-electrode recordings in macaque primary visual cortex

Area of Science:

• Neuroscience
• Biomedical Engineering
• Implantable Devices

Background:

• Large-scale invasive neural recordings are crucial for neuroscience research.
• Existing technologies face challenges in large animals due to brain size and complexity.
• There is a need for chronic, high-density neural recording solutions in primates and humans.

Purpose of the Study:

• To evaluate thin, flexible multi-electrode arrays (MEAs) for long-term neural recording in macaque monkeys.
• To assess the electrical, mechanical, and magnetic resonance imaging (MRI) properties of the MEAs.
• To determine the capacity of MEAs for recording neuronal activity over one year.

Main Methods:

• Flexible MEAs with resorbable poly(lactic-co-glycolic acid) coating were designed for insertion.
• Arrays were implanted into the primary visual cortex of two macaque monkeys.
• In vivo and ex vivo MRI compatibility and neural recording capabilities were assessed over 12 months.

Main Results:

• The MEAs demonstrated excellent MRI compatibility.
• Clear single-unit and multi-unit activity (MUA) were recorded from a high percentage of electrodes.
• Stable MUA responses and receptive fields were maintained for up to one year post-implantation.

Conclusions:

• Thin, flexible MEAs offer significant advantages in brain tissue compliance, scalability, and coverage compared to existing arrays.
• These MEAs show promise for advanced brain-machine interface applications in humans.
• The developed technology facilitates long-term, high-resolution neural monitoring in large animal models.