Knowledge Base

References

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History of CatWalk

(Text by Frank Hamers, MD, PhD — October 24, 2005)

CatWalk was developed by Dr. Frank Hamers (Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, The Netherlands) as a research tool for his work on functional recovery from spinal cord contusion injury in the rat. Development started in the summer of 1996, after he had spent a month at the lab of Dr. Michael Beattie and Jacqueline Bresnahan at OSU (Columbus, OH) to gain experience with the newly developed Basso-Beattie-Bresnahan locomotor rating scale (BBB-test), a very sensitive and reproducible open-field test for assessment of locomotor recovery in this animal model.

An important landmark in the BBB-test is the return of FL-HL coordination, something which may be difficult to see with the naked eye. The definition used in the BBB-score is an operational one, as it is impossible to follow all four paws at the same time: even with two observers (the recommended setup for BBB-testing) each observer only sees at most three paws at the same time. Several months earlier, Frank Hamers had read some papers written by Kenneth Clarke (University of Sheffield, UK) who used a special walkway enabling evaluation of paw-floor contact with unprecedented detail for his research on gait development in rat puppies. Frank Hamers believed that such a walkway might be used to enable better evaluation of FL-HL coordination in spinal cord lesioned animals, and back in Utrecht a prototype of the walkway was built: it behaved as expected.

The first full-featured walkway was built in a weekend by Jan Brakkee, the chief biotechnician in the regeneration group, and several others have been built by the author himself since then. Frank Hamers had well-developed software engineering skills — in fact, since he enrolled in the lab as a PhD student in 1988 he largely automated data acquisition across the whole of the regeneration group — and as such he set out to write a simple videotaping program to capture animals crossing the walkway. This was the prototypical CatWalk program which eventually evolved into the program as it exists today. This evolution was driven by Frank Hamers' own research questions and those of his collaborators using the system, the more so as regeneration research was banned from the Pharmacology & Anatomy lab shortly after 2001.

For instance, assessment of coordination is just one of the many things that the program can be used for, and its ability to assess FL-HL coordination in an unbiased way has only recently been combined with the BBB-test by Guido Koopmans, a former PhD student in Bert Joosten's lab at Maastricht University. The first meaningful results with the system were presented at the Annual Neurotrauma Symposium in Miami Beach in November 1999. The second and third systems were set up by Frank Hamers at Jacqui Bresnahan's lab at OSU and at Barbara Bregman's lab at Georgetown University in September 2000, followed almost immediately by a system in Joost Verhaagen's lab at the Netherlands Institute for Brain Research in Amsterdam. Since then, the number of installed systems has greatly expanded and the value of the system in many different nervous system lesion models and others has become increasingly clear.