Optogenetic modulation of long-range cortical circuits in awake nonhuman primates

Area of Science:

• Neuroscience
• Systems Neuroscience
• Primate Research

Background:

• Studying complex cognitive processes requires causal control of neural networks.
• Optogenetics offers precise genetic and temporal control of neural circuits.
• Current optogenetic methods in nonhuman primates (NHPs) often lack the ability to test inter-network connections.

Purpose of the Study:

• To describe a novel approach combining optogenetics and electrophysiology in awake NHPs.
• To enable manipulation and monitoring of both short- and long-range feedforward and feedback circuits.
• To provide detailed methodology for NHP-specific optogenetic targeting and viral vector application.

Main Methods:

• Viral vector injection for targeting intra- and interareal cortical projections.
• Simultaneous electrophysiological recordings with optogenetic stimulation at various cortical distances.
• Focal biopsy for evaluating gene expression and focal stimulation.

Main Results:

• Demonstrated a method for optogenetic manipulation of cortical projections in NHPs.
• Successfully combined optogenetic stimulation with electrophysiological recordings in awake NHPs.
• Detailed NHP-specific considerations for injection site targeting, viral constructs, and behavioral measures.

Conclusions:

• The described approach allows for causal control of short- and long-range circuits in NHPs.
• This method is valuable for investigating systems neuroscience questions, including attention and contrast normalization.
• The technique requires expertise in in vivo awake electrophysiology with NHPs and specific preparation timelines.