Generating Mice with Optogenetic Control

All experimental procedures were approved by the committee for the Care and Use of Laboratory animals of the Government of Upper Bavaria, Germany. Mice selectively expressing ChR2(H134R)-EYFP in forebrain glutamatergic neurons were generated by breeding homozygous NEX-Cre mice (Goebbels et al., 2006 (link)) to homozygous Ai32 mice (Madisen et al., 2012 (link); purchased from the Jackson Laboratory). Genotyping was performed using the following primers specific for NEX-Cre: NEXCre4 5′-GAG-TCC-TGG-AAT-CAG-TCT-TTT-TC-3′, NEXCre5 5′-AGA-ATG-TGG-AGT-AGG-GTG-AC-3′, and NEXCre6 5′-CCG-CAT-AAC-CAG-TGA-AAC-AG-3′. Standard PCR conditions resulted in a Cre-specific PCR product of 525-bp and a wild-type PCR product of 770-bp. Genotyping for ChR2 was conducted according to the genotyping protocol provided by the Jackson Laboratory. All animals were housed under a 12 h light/dark cycle starting 5 days before the experiment and had access to water and food ad libitum. All experiments were performed in 8- to 12-week-old male mice.