Seven years of recording from monkey cortex with a chronically implanted multiple microelectrode.

Area of Science:

• Neuroscience
• Primate research
• Electrophysiology

Background:

• Chronic neural recordings are crucial for understanding brain function.
• Minimizing tissue damage during electrode implantation is essential for long-term stability.
• Current implantation methods can cause significant damage to cortical tissue.

Purpose of the Study:

• To present a novel, minimally invasive surgical technique for chronic microwire implantation.
• To evaluate the long-term stability and recording quality of neural implants.
• To assess the extent of tissue damage associated with the new implantation method.

Main Methods:

• A brush of 64 microwires was implanted in the ventral premotor cortex of a macaque monkey.
• Wires were inserted from the white matter side, avoiding direct penetration of the cortical surface.
• Neural activity (isolated potentials and multiunit activity) was recorded for over 7 years.

Main Results:

• One-third of electrodes provided stable recordings for more than 7 years.
• The indirect insertion method minimized mechanical pressure on the dura and pia mater.
• Histological examination revealed only marginal damage to the cortical recording site.
• Excellent recording stability was achieved within and across sessions, with some neurons tracked for years.

Conclusions:

• The white matter insertion technique offers a minimally invasive approach for chronic microwire implantation.
• This method significantly improves long-term neural recording stability and data quality.
• The technique provides a valuable tool for long-term studies of brain function in non-human primates.