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From test arena to habitat: multi-cage video tracking and behavioral observation in group-housed rats

Supervisor: Prof. dr. Lucas Noldus, Section Neurophysics, Donders Institute for Brain, Cognition and Behavior, Radboud University

Co-supervisor: Prof. dr. Judith Homberg, Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center

Background and objectives

For the foreseeable future, the discovery and development of new therapies for human brain disorders will require research on animals, in particular mice and rats. Full understanding of an animal’s response to internal or external stimuli requires measurement of multiple biomarkers: visible (behavior), acoustic (audible sounds, ultrasonic vocalizations) and physiological parameters (cardiovascular, respiratory, brain activity and other signals). In line with the principles of Refinement, Reduction and Replacement (3Rs) of animal testing, we strive to collect this data in a continuous fashion, in an environment that mimics the natural habitat of rodents (such as social housing in an enriched cage), with minimal discomfort for the animals.

This project will focus on the physical environment in which rodents are tested. During the past 20 years, behavioral neuroscientists have become increasingly convinced that an enriched cage with bedding, food, drink and shelter has a higher ecological validity as a test environment than a barren test arena. An example of such an enriched cage is the PhenoTyper (www.noldus.com/phenotyper), which can be used to measure sleep-wake cycles, individual and social behavior as well as the response to challenges. Using a variety of sensors and stimulus devices, protocols can be programmed to investigate attention, cognition, hedonic preference, anxiety and other mental states. As the number of enrichment objects, stimulus and response devices grows, the test cage runs the risk of losing its ecological validity.

Just like we humans don’t perform all activities of daily living in the same room, with family members as well as strangers, it makes sense to enlarge the rodent test environment and separate ‘residential activities’ (eating, drinking, sleeping) from ‘work’ (various cognitive and physical tasks). A larger space also provides more options for social structures to manifest themselves more naturally. Several European research groups have been experimenting with this idea, but their efforts are limited in scope (e.g. limited to cage transitions, no behavioral or acoustic recording). In the proposed project, this concept will be tested by connecting multiple PhenoTyper cages to form a multi-cage habitat. Each cage will be equipped with different facilities and devices, depending on its functional assignment. The data streams acquired in each cage will need to be integrated in a novel manner, to allow animal tracking and behavioral analysis at the habitat level.

The research project

This internship will encompass the following phases:

  • Literature study of past and ongoing initiatives related to multi-cage rodent research setups
  • Design of an initial habitat using two PhenoTyper cages, connected with a tunnel
  • Observing and tracking 2-4 rats in the setup, using video tracking software
  • Mounting RFID ring antennas to detect animal transitions between cages
  • Integrate RFID data with the video tracking data of all rats in all cages
  • Design of software for multi-animal behavioral analysis at the habitat level
  • Expand the habitat to 3 or more cages

During this internship, you will use state-of-the-art tools for video tracking, behavior recognition and experiment automation (EthoVision, www.noldus.com/ethovision) and ultrasonic vocalization recording and analysis (UltraVox, www.noldus.com/ultravox). On top of that you will develop new data analysis and visualization software. The scope of the project (e.g. the size of the habitat and the number of modalities being recorded and integrated) will depend on the amount of time available and the outcome of the analysis during the first phase in the project. You will perform the tests on rats that are subjects in ongoing animal studies, under daily supervision of a PhD student or postdoctoral researcher. Hardware design and engineering will be supported by mechanical and electronic engineers of DCN’s technical services group.

Work environment

As a research intern in the Donders Center for Neuroscience (DCN), you join a vibrant community of more than 200 researchers, technical and support staff. DCN is part of the world-renowned Donders Institute for Brain, Cognition and Behavior. With more than 20 nationalities represented in our center, our common language is English. You will become a member of the local research community “Rodent behavior and bioacoustics” consisting of Prof. Lucas Noldus, Prof. Judith Homberg, Dr. Bernhard Englitz, postdoctoral researchers, PhD candidates and master students, some 15 in total. The project will be carried out in collaboration with Noldus Information Technology in Wageningen, a leading developer of research tools for behavioral neuroscience. During the internship you will be able to visit the company and get a sense of a work environment outside academia. For the analysis of ultrasonic vocalizations, you will collaborate with Brain Builders, a local AI company who develop the UltraVox software. If your project is successful, the results may be published in a journal paper, of which you will become a co-author.

Requirements

  • Education: Bachelor’s degree in computer science, physics, AI or related discipline
  • Knowledge: Basic understanding of video tracking, bioacoustics, signal processing, pattern recognition
  • Skills: Programming in Python; experience with Jupyter Notebook and relevant libraries (OpenCV, FFmpeg, NumPy, SciPy, Pandas) is an advantage
  • Interest: Mechanical engineering, animal behavior, animal models of human brain disorders, preclinical research

Practical information

  • Duration: 5-6 months
  • Location of work: Donders Center for Neuroscience, Huygens Building (office work) and Central Animal Facility (experimental work) on the Radboud University campus

Contact information

Prof. dr. Lucas P.J.J. Noldus, Section Neurophysics, Donders Center for Neuroscience, Radboud University

Address: Huygens Building, Room 00.136, Heyendaalseweg 135, 6525 AJ Nijmegen

Phone: +31-6-53425199

Email: lucas.noldus@donders.ru.nl

RU-homepage: https://www.ru.nl/en/people/noldus-l

LinkedIn: http://www.linkedin.com/in/lucasnoldus