Monosynaptic rabies virus tracing from projection-targeted single neurons

Area of Science:

• Neuroscience
• Molecular Biology
• Systems Neuroscience

Background:

• Single neurons integrate vast inputs, but mapping their presynaptic connections is challenging.
• Existing rabies virus tracing (RVΔG) methods lack efficiency and validation for single-neuron resolution.

Purpose of the Study:

• To establish an efficient and validated method for monosynaptic tracing from projection target-defined single neurons.
• To improve the accuracy and success rate of RVΔG tracing for dissecting neural circuits.

Main Methods:

• Utilized TVA950 receptor for initial viral infection of targeted single neurons.
• Employed EnvA-pseudotyped G-deleted rabies virus (RVΔG) for transsynaptic labeling in adult mice.
• Focused on single neuronal networks within the primary visual cortex (V1) and higher visual areas (PM, AM).

Main Results:

• Achieved an 80% success rate for transsynaptic labeling from surviving TVA950-expressing starter neurons.
• Successfully mapped single neuronal networks in V1, PM, and AM, including PM-projecting V1 neurons.
• Revealed the input-output organization of single neuronal networks using projection target-defined tracing.

Conclusions:

• The developed RVΔG tracing method enhances efficiency and accuracy for single-neuron circuit analysis.
• This approach facilitates the dissection of neural circuit heterogeneity and the linkage of circuit motifs across scales.
• Enables a clearer understanding of information processing and circuit computation in the brain.