Chronically implantable μLED arrays for optogenetic cortical surface stimulation in mice.

Area of Science:

• Neuroscience
• Bioengineering
• Medical Devices

Background:

• Cortical implants are crucial neurotechnologies for studying cognitive processes.
• Optogenetics provides cell-type specificity but faces challenges in achieving high-density, chronic stimulation.
• Complex neuronal networks require precise tools for selective probing and stimulation.

Purpose of the Study:

• To develop and evaluate a high-density micro-LED array for chronic optogenetic stimulation of the mouse cortex.
• To assess the stability, efficacy, and safety of the implantable micro-LED system.
• To demonstrate the utility of the device in modulating neural activity and behavior.

Main Methods:

• Fabrication of 100-element micro-LED arrays with 200 μm pixel pitch and a 2x2 mm² footprint.
• Chronic implantation of the micro-LED system in freely-behaving mice.
• Simultaneous electrophysiology recordings and behavioral outcome measurements.

Main Results:

• Micro-LED arrays demonstrated stable in vivo operation for over 300 hours.
• Robust neuronal responses were achieved at low drive currents (<5 mA), minimizing thermal effects.
• Spatiotemporal, patterned optogenetic stimulation successfully drove behavioral outcomes in auditory cortical circuits.

Conclusions:

• The developed micro-LED array system is a viable tool for chronic, high-resolution optogenetic stimulation of the cortex.
• This technology facilitates long-term investigation of neural circuit function and its relation to behavior.
• The system offers a promising approach for advancing neurotechnology and understanding cognitive functions.