Accessing genetically defined cell types in the superior colliculus with transgenic mouse lines.

Recent studies have revealed diverse neuron types in the superior colliculus (SC), a midbrain structure critical for sensorimotor transformation. Here, as an important step toward studying the function of these subtypes, we characterize 10 transgenic mouse lines based on a recently published molecular atlas of the superficial SC. We show that Cre or fluorescence expression in some lines corresponds specifically to certain transcriptomic neuron types. These include two GENSAT lines that have been used to target morphological cell types in the SC and three knockin lines. In contrast, such a correspondence is not seen in other tested mice. Importantly, the expression pattern of marker genes in all these lines is highly consistent with the molecular atlas. Together, our studies support a correlation between morphological and transcriptomic neuron types, identify useful lines for targeting SC neuron types genetically, and demonstrate the validity of the single-cell transcriptomics data.