Sapphire-Based Optrode for Low Noise Neural Recording and Optogenetic Manipulation

Area of Science:

• Neuroscience
• Biomedical Engineering
• Materials Science

Background:

• Optogenetic stimulation and electrophysiological recordings are crucial for understanding neural activity in behavior and cognition.
• Advancements in implantable optrodes are needed to improve spatiotemporal resolution for research and clinical applications.
• A lack of robust, integrated neural optrodes combining recording arrays and high-intensity light-emitting diodes (LEDs) exists.

Purpose of the Study:

• To propose and validate a novel neural optrode based on Gallium Nitride (GaN) on sapphire technology.
• To integrate a high-intensity blue LED with a 5x2 recording array monolithically for simultaneous neural recording and optogenetic manipulation.
• To demonstrate the optrode's capability for precise deep brain region access and neural activity manipulation.

Main Methods:

• Developed a monolithic neural optrode using Gallium Nitride (GaN) on sapphire technology.
• Integrated a high-intensity blue LED with a 5x2 recording array.
• Incorporated three metal grounding interlayers to mitigate noise interference between the LED and recording electrodes.
• Validated noise reduction using electromagnetic simulations and experimental demonstrations.
• Performed in vivo electrophysiological recordings in mouse olfactory bulbs and gerbil medial superior olive (MSO) neurons.

Main Results:

• Successfully demonstrated simultaneous neural recording and optogenetic stimulation using the GaN optrode.
• Confirmed significant reduction of LED-induced artifacts in neural recordings due to the grounding interlayers.
• Recorded action potentials from mitral/tuft cells in mouse olfactory bulbs.
• Observed elevated action potential firing in gerbil MSO neurons upon optogenetic stimulation, confirming deep brain region access.

Conclusions:

• The proposed Gallium Nitride (GaN) on sapphire optrode offers a robust solution for simultaneous neural recording and optogenetic manipulation.
• The integrated design and noise-reduction techniques enable precise access to neural activities in deep brain regions.
• This technology holds promise for advancing neuroscience research and future clinical applications requiring high spatiotemporal resolution.