Feeding Experimentation Device version 3 (FED3): An open-source home-cage compatible device for measuring food intake and operant behavior

Abstract

SummaryFeeding is critical for survival and disruption in the mechanisms that govern food intake underlie disorders such as obesity and anorexia nervosa. It is important to understand both food intake and food motivation to reveal mechanisms underlying feeding disorders. Operant behavioral testing can be used to measure the motivational component to feeding, but most food intake monitoring systems do not measure operant behavior. Here, we present a new solution for monitoring both food intake and motivation: The Feeding Experimentation Device version 3 (FED3). FED3 measures food intake and operant behavior in rodent home-cages, enabling longitudinal studies of feeding behavior with minimal experimenter intervention. It has a programmable output for synchronizing behavior with optogenetic stimulation or neural recordings. Finally, FED3 design files are open-source and freely available, allowing researchers to modify FED3 to suit their needs. In this paper we demonstrate the utility of FED3 in a range of experimental paradigms.In BriefUsing a novel, high-throughput home cage feeding platform, FED3, Matikainen-Ankney et al. quantify food intake and operant learning in groups of mice conducted at multiple institutions across the globe. Results include rates of operant efficiency, circadian feeding patterns, and operant optogenetic self-stimulation.HighlightsThe Feeding Experimentation Device version 3(FED3) records food intake and operant behavior in rodent home cages.Analysis of food intake includes total intake, meal pattern analysis, and circadian analysis of feeding patterns.FED3 also allows for operant behavioral assays to examine food learning and motivation.

Metabolic sensing in AgRP neurons integrates homeostatic state with dopamine signalling in the striatum

“…This exploits the fact that food restriction enhances appetitive drive, which is a result of elevated AgRP neuronal activity ( Krashes et al, 2011 ; Chen et al, 2016 ). To avoid this potential confound we placed the open source Feeding Experimental Device 3 (FED3) ( Matikainen-Ankney et al, 2021 ) in home cages to facilitate learning in a low stress environment for long periods of time. As such, operant learning can be acquired quickly and easily in ad libitum-fed mice without the need for caloric restriction – an important consideration for our experiments in which differential feeding responses to fasting, as reported previously ( Reichenbach et al, 2018c ; Reichenbach et al, 2018b ), may affect task acquisition and performance ( Figure 3A ).…”

“…For operant conditioning experiments, Feeding Experiment Devices version 3 (FED3)( Matikainen-Ankney et al, 2021 ) were placed overnight (16 hr) inside home cages under ad libitum conditions trained to reliably nose poke on fixed ratio (FR)1, FR3, and FR5 schedules (criteria to move to higher schedule was three consecutive days over 75% correct nose pokes) The dispensing of a sugar pellet (20 mg, 65% sucrose, 5TUT Test Diets, Saint Louis, Missouri, USA) was paired with an LED light cue. During these FR sessions, a nose poke in the ‘active’ hole resulted in the delivery of a sugar pellet and was paired with a LED light cue whereas a nose poke in the ‘inactive’ hold resulted in no programmed response.…”

Identification of a stress-sensitive anorexigenic neurocircuit from medial prefrontal cortex to lateral hypothalamus

“…To assess whether the mPFC-LH pathway suppresses motivated behavior to obtain a food reward (20mg sucrose pellet), we used a FED3 home cage operant conditioning system (22). Mice were trained on FR1-FR3-FR5 schedules until all mice correctly selected the active nose poke 75% of total pokes performed (Fig 4J), and then were subjected to a progressive ratio task following CNO injection (Fig 4K) either in a mildly fasted or ad libitum fed state at the start of the dark phase.…”

“…For detailed description of behavior experiments and operant conditioning experiments using the feeding experimental devices 3 (FED3; Open Ephys, Portugal) (22) see supplemental methods and materials.…”

“…First, activation of the mPFC-LH circuit during the early light phase, the period when mice are typically inactive (Fig 4D ), significantly suppressed food intake after 4 hours (Fig 4G). We also examined food intake following a short-term 3hr fast to normalize feeding status during the dark phase, the period when mice consume most of their energy intake ( To assess whether the mPFC-LH pathway suppresses motivated behavior to obtain a food reward (20mg sucrose pellet), we used a FED3 home cage operant conditioning system (22). Mice were trained on FR1-FR3-FR5 schedules until all mice correctly selected the active nose poke 75% of total pokes performed ( There were also no differences in expression of walking, stationary, and rearing behaviors in the open field after DREADD activation.…”