# Key Points from the IRC Discussion

• Researchers discussed brain imaging technologies for connectomics, debating the feasibility of using aptamers to label brain cell surface receptors, with an estimated cost of $3M to develop a library targeting approximately 120 receptors.

• Fluorescent In Situ Sequencing (FISSEQ) was explored as a promising technique for molecularly-annotated connectomics, which transforms neural mapping from an imaging challenge to a sequencing and data mining problem.

• The discussion compared tissue sectioning methods for connectome reconstruction, including knife-edge scanning microscopy versus laser or electron beam approaches (like FIB-SEM), evaluating tradeoffs between cost, speed, and preservation of fine neural structures.

• Cellular barcoding technologies were extensively discussed, including a Cre Lox system for in situ barcoding that creates stable genetic identifiers in neurons without requiring ex vivo viral transduction.

• Researchers referenced Marblestone's "Rosetta Brains" strategy for molecularly-annotated connectomics and a newer paper on mapping single neuron projections through barcoded RNA sequencing.

• Various viral vectors for neural tagging were examined, including modified Sindbis virus and pseudorabies virus that can deliver genetic material to neurons without propagating further.

• A CRISPR-based anti-aging research project was mentioned that would test youth-restoring genes in elderly Arabian horses as a demonstration of efficacy in larger animals before human applications.