This mouse strain has loxP sites flanking exons 3 and 4 of the ChAT gene. There is a Neo gene in the intron between exons 4 and 5. Mating these mice to A-Cre mice generates a null allele in subsequent generations, in which no ChAT protein or activity is detectable. The mice are maintained in the C57/B6 background. The strain was used to study synaptic efficacy in synaptic competition.