Meaghan Creed has developed a novel device for assessing preferences by mice among fluids in their homecages, i.e. two-bottle choice test. She shared the design on http://hackaday.io and contributed the summary of it below.
Often in behavioral neuroscience, we need to measure how often and how much a mouse will consume multiple liquids in their home cage. Examples include sucrose preference tasks in models of depression, or oral drug self-administration (ie. Morphine, opiates) in the context of addiction. Classically, two bottles are filled with liquids and volumes are manually recorded at a single time point. Here, we present a low-cost, two-sipper apparatus that mounts on the inside of a standard mouse cage. Interactions are detected using photointerrupters at the base of each sipper which are logged to an SD card using a standard Arduino. Sippers are constructed from 15 mL conical tubes which allows additional volumetric measurements, the rest of the holding apparatus is 3D printed, and the apparatus is constructed with parts from Arduino and Sparkfun. This automated approach allows for high temporal resolution collected over 24 hours, allowing measurements of patterns of intake in addition to volume measurements. Since we don’t need to manually weigh bottles we can do high-throughput studies, letting us run much larger cohorts.
This is designed such that each set of 2 sippers uses its own Arduino and SD card. With a bit of modification to the code one Arduino Uno can be programmed to log from 6 cages onto the same SD card. Arduino compatible boards with more GPIOs (like Arduino Mega) can log from up to 56 sippers on one Arduino.
From the Kravitz lab at the NIH comes a simple device for dispensing pre-measured quantities of food at regular intervals throughout the day. Affectionately known as “SnackClock”, this device uses a 24-hour clock movement to rotate a dispenser wheel one revolution per day. The wheel contains 12 compartments, which allows the device to dispense 12 pre-measured “snacks” at regular 2 hour intervals. The Kravitz lab has used this device to dispense high-fat diet throughout the day, rather than giving mice one big piece once per day. The device is very simple to build and use, requiring just two 3D printed parts and a ~$10 clock movement. There is no microcontroller or coding required for this device, and it runs on one AA battery for >1 year. The 3D files are supplied and can be edited to fit SnackClock in different brands of caging, or to adjust the number of snack compartments. With additional effort the clock movement could be replaced by a stepper motor to allow for dispensing at irregular or less frequent intervals.
An interesting summary of recent methods for monitoring behavior in rodents was published this week in Nature.The article mentions Lex Kravitz and his lab’s efforts on the Feeding Experimentation Device (FED) and also OpenBehavior. Check it out: https://www.nature.com/articles/d41586-018-02403-5
Alexxai Kravitz has generously shared the following regarding FED, part 2:
The Feeding Experimentation Device (FED) is a free, open-source system for measuring food intake in rodents. FED uses an Arduino processor, a stepper motor, an infrared beam detector, and an SD card to record time-stamps of 20mg pellets eaten by singly housed rodents. FED is powered by a battery, which allows it to be placed in colony caging or within other experimental equipment. The battery lasts ~5 days on a charge, providing uninterrupted feeding records over this duration. The electronics for building each FED cost around $150USD, and the 3D printed parts cost between $20 and $400, depending on access to 3D printers and desired print quality.
The Kravitz lab has published a large update of their Feeding Experimentation Device (FED) to their Github site, including updated 3D design files that print more easily and updates to the code to dispense pellets more reliably.
The openBehavior github repository from Hao Chen’s lab at UTHSC aims to establish a computing platform for rodent behavior research using the Raspberry Pi computer. They have built several devices for conducting operant conditioning and monitoring environmental data.
The operant licking device can be placed in a standard rat home cage and can run fixed ratio, various ratio, or progressive ratio schedules. A preprint describing this project, including data on sucrose vs water intake is available. Detailed instructions for making the device is also provided.
The environment sensor can record the temperature, humidity, barometric pressure, and illumination at fixed time intervals and automatically transfer the data to a remote server.
Feeding Experimentation Device (FED) is a home cage-compatible feeding system that measures food intake with high accuracy and temporal resolution. FED offers a low-cost alternative (~$350) to commercial feeders, with the convenience of use in tradition colony rack caging.
KravitzLab has shared the Arduino scripts for controlling FED, as well as, the python code used to analyze the feeding data collected by FED on the KravitzLab Github. Additionally, build instructions and power considerations are detailed on the FED Wiki page and 3D Design Files provided through TinkerCAD.