Two-color Multifiber Photometry Recordings of the Social Behavior Network in Mice

Fiber photometry, the bulk recording of signals through a fiber optic cable, is a useful method for recording calcium activity from groups of neurons in the freely moving rodent. In particular, this method makes targeting small populations of genetically specified neurons in more ventral and less accessible areas of the brain a tractable problem, since it remains challenging to record at cellular resolution. This technique can be scaled to record from multiple sites simultaneously using a bundled multifiber approach and can target multiple cell types using genetic strategies at each recorded site. Here, we provide a protocol for how to build and insert customized multifiber arrays for targeting the mouse social behavior network (up to 12 sites). This protocol details the surgical operating procedures required for successful targeting of multiple sites using our customized multifiber arrays and the viral approach for delivery of green- and red-shifted fluorescent indicators of calcium activity for simultaneous imaging of two genetically identified neural populations at each site. We demonstrate how to record from these regions using a commercially available complementary metal-oxide semiconductor (CMOS) camera system during social behavior. Further, this protocol demonstrates methods for quality control and details a preprocessing pipeline for noise correction and standardization. Finally, we discuss some potential applications of the tool to uncover novel findings about large-scale brain networks.