PeerPub: A Device for Concurrent Operant Oral Self-Administration by Multiple Rats.

The social environment has long been recognized to play an important role in substance use, which is often modeled in rodents using operant conditioning. However, most operant chambers only accommodate one rodent at a time. We present PeerPub - a unique social operant chamber. PeerPub employs touch sensors to track the licking behavior on drinking spouts. When the number of licks meets a set reinforcement schedule, it dispenses a drop of solution with a fixed volume as a reward at the tip of the spout. A radio-frequency identification (RFID) chip implanted on each rat's skull identifies it throughout the experiment. The system is managed by a Raspberry Pi computer. We evaluated PeerPub using Sprague Dawley rats in daily one-hour sessions, where supersac (a glucose and saccharin solution) was provided under a fixed ratio 5 schedule. We discovered that male rats consumed more supersac in dual rat conditions compared to single rat conditions. These findings illustrate PeerPub's effectiveness in modeling the interaction between motivated behavior and social context. We expect devices like PeerPub will help highlight the role of social environments in substance use disorder phenotypes. All computer code, 3D design, and build instructions for PeerPub can be found at http://github.com/nijie321/PeerPub. Social environments significantly influence food and drug consumption, but traditional operant chambers limit the study of these effects by accommodating only single animals. PeerPub, a novel social operant chamber, addresses this gap by enabling simultaneous oral operant drug self-administration in multiple rats. Using RFID and touch sensors, PeerPub tracks individual licking behaviors and delivers appropriate rewards for each individual. Testing with Sprague Dawley rats revealed that social interactions influence consumption behaviors, with male rats consuming more in social settings. PeerPub offers a powerful tool for studying the interplay between social context and motivated behavior, providing valuable insights into substance use disorder phenotypes and aiding in the development of effective prevention and treatment strategies.