To enable genetic access without genetically engineered animals, we developed and benchmarked enhancer-AAVs for selectively targeting dopamine (DA) neurons across mice and marmosets. 12 DA enhancer candidates were nominated through integrated single-nucleus RNA-seq/ATAC-seq analysis of marmoset ventral midbrain tissue. We identified two leads (cjDAE8, cjDAE4) by systemic AAV delivery and dual-color fluorescence screening in mice. Local co-injection of both AAVs in marmoset confirmed DA-restricted expression, with cjDAE8 exhibiting higher specificity. However, antibody amplification of reporter fluorescence exposed weakly labeled off-target cells (leaky expression). We therefore engineered next-generation AAV backbones for cjDAE8 to strengthen expression while limiting leakiness. Quantitative histology comparing natural versus antibody-amplified fluorescence defined AAV doses for achieving both high efficiency and greater than 90-95% specificity of DA neuron labeling across injection routes. We demonstrate applications for (i) retrograde targeting of projection-defined DA populations in marmoset, (ii) fiber-photometric recording of divergent DA-axonal dynamics in mouse striatal subregions, and (iii) driving optogenetic VTA DA self-stimulation. Our results provide a resource for interspecies DA targeting and two practical guidelines: backbone context critically shapes enhancer performance, and antibody-amplified readouts rigorously assesses specificity.
Neural manifolds that orchestrate walking and stopping
Walking, stopping and maintaining posture are essential motor behaviors, yet the underlying neural processes remain poorly understood. Here, we investigate neural activity behind locomotion and