Quantitative Characterization and Classification of Leech Behavior

• Published in: Journal of neurophysiology Vol. 93; no. 1; pp. 580 - 593
• Main Authors: Mazzoni, Alberto, Garcia-Perez, Elizabeth, Zoccolan, Davide, Graziosi, Sergio, Torre, Vincent
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-01-2005
• Subjects: Animals; Behavior, Animal - classification; Behavior, Animal - physiology; Exploratory Behavior - physiology; Hirudinea; Invertebrata; Litchi - physiology; Locomotion - physiology; Microspheres; Models, Neurological; Motor Activity - physiology; Periodicity; Photography - methods; Physical Stimulation - methods; Spectrum Analysis; Swimming - physiology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00608.2004

1 Scuola Internazionale Superiore di Studi Avanzati and Instituto Nazionale Fisica della Materia Section Trieste, Italy; and 2 McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts
Submitted 15 June 2004;
accepted in final form 6 August 2004
This paper describes an automatic system for the analysis and classification of leech behavior. Three colored beads were attached to the dorsal side of a free moving or pinned leech, and color CCD camera images were taken of the animal. The leech was restrained to moving in a small tank or petri dish, where the water level can be varied. An automatic system based on color processing tracked the colored beads over time, allowing real-time monitoring of the leech motion for several hours. At the end of each experimental session, six time series (2 for each bead) describing the leech body motion were obtained. A statistical analysis based on the speed and frequency content of bead motion indicated the existence of several stereotypical patterns of motion, corresponding to different leech behaviors. The identified patterns corresponded to swimming, pseudo-swimming, crawling, exploratory behavior, stationary states, abrupt movements, and combinations of these behaviors. The automatic characterization of leech behavior demonstrated here represents an important step toward understanding leech behavior and its properties. This method can be used to characterize the behavior of other invertebrates and also for some small vertebrates.
Address for reprint requests and other correspondence: V. Torre, c/o SISSA, Via Beirut 2, 34014 Trieste, Italy (E-mail: torre{at}sissa.it )