Genetically-encoded activity imaging was coupled with the development and application of methods for optogenetic control of multiple individually defined cells to both optically monitor and manipulate the activity of many orbitofrontal cortex neurons at the single-cell level in real time during rewarding experiences.
All in vivo two-photon experiments were conducted with a customized Ultima IV microscope (Bruker) and a 20×/0.45-NA LCPLN20XIR objective (Olympus) fitted with a GRIN lens to improve depth of focus. Two separate femtosecond-pulsed laser beams controlled by independent sets of XY galvanometric scanning mirrors were used for simultaneous calcium imaging and optogenetic stimulation experiments. Sequential spiral stimulation was performed using Prairie View 5.4 software (Bruker).
Distinct populations of neurons within the orbitofrontal cortex were identified that selectively responded to either feeding or social stimuli. The activity of individually specified naturally feeding-responsive neurons was causally linked to increased feeding behavior. These results reveal the presence of potent cellular-level subnetworks within the orbitofrontal cortex that can be precisely engaged to bidirectionally control feeding behaviors subject to, for example, social influences.