The logic of single-cell projections from visual cortex

摘要

Neocortical areas communicate via extensive axonal projections, but the logic of information transfer is unresolved because the projections of individual neurons have not been systematically characterized. It is unknown whether individual neurons send projections only to single cortical areas, or instead distribute signals across multiple targets. Here we determined the projection patterns of 591 individual neurons in mouse primary visual cortex (V1) using whole-brain fluorescence-based axonal tracing and high-throughput DNA sequencing of genetically barcoded neurons (MAPseq). Projections were highly diverse and divergent, collectively targeting at least 18 cortical and subcortical areas. Most neurons target multiple cortical areas, often in non-random combinations, suggesting the existence of sub-classes of intracortical projection neurons. Thus the dominant mode of intracortical information transfer is not based on “one neuron – one target area” mapping. Instead, signals carried by individual cortical neurons are shared across subsets of target areas, and thus concurrently contribute to multiple functional pathways.