A major challenge of neuroscience is to understand the circuit and gene bases of behavior. C. elegans is commonly used as a model system to investigate how various gene products function at specific tissue, cellular, and synaptic foci to produce complicated locomotory and bending behavior. The investigation generally requires quantitative behavioral analyses using an automated single-worm tracker, which constantly records and analyzes the position and body shape of a freely moving worm at a high magnification. Many single-worm trackers have been developed to meet lab-specific needs, but none has been widely implemented for various reasons, such as hardware difficult to assemble, and software lacking sufficient functionality, having closed source code, or using a programming language that is not broadly accessible. The lack of a versatile system convenient for wide implementation makes data comparisons difficult and compels other labs to develop new worm trackers. Here we describe Track-A-Worm, a system rich in functionality, open in source code, and easy to use. The system includes plug-and-play hardware (a stereomicroscope, a digital camera and a motorized stage), custom software written to run with Matlab in Windows 7, and a detailed user manual. Grayscale images are automatically converted to binary images followed by head identification and placement of 13 markers along a deduced spline. The software can extract and quantify a variety of parameters, including distance traveled, average speed, distance/time/speed of forward and backward locomotion, frequency and amplitude of dominant bends, overall bending activities measured as root mean square, and sum of all bends. It also plots worm travel path, bend trace, and bend frequency spectrum. All functionality is performed through graphical user interfaces and data is exported to clearly-annotated and documented Excel files. These features make Track-A-Worm a good candidate for implementation in other labs.
References
[1]
Cronin CJ, Mendel JE, Mukhtar S, Kim YM, Stirbl RC, et al. (2005) An automated system for measuring parameters of nematode sinusoidal movement. BMC Genet 6: 5.
[2]
Feng Z, Cronin CJ, Wittig JH Jr, Sternberg PW, Schafer WR (2004) An imaging system for standardized quantitative analysis of C. elegans behavior. BMC Bioinformatics 5: 115.
[3]
Tsibidis GD, Tavernarakis N (2007) Nemo: a computational tool for analyzing nematode locomotion. BMC Neurosci 8: 86.
[4]
Leifer AM, Fang-Yen C, Gershow M, Alkema MJ, Samuel AD (2011) Optogenetic manipulation of neural activity in freely moving Caenorhabditis elegans. Nat Methods 8: 147–152.
[5]
Li W, Feng Z, Sternberg PW, Xu XZS (2006) A C. elegans stretch receptor neuron revealed by a mechanosensitive TRP channel homologue. Nature 440: 684–867.
[6]
Rivera LI, Potsaid B, Wen JTY (2008) Multi-worm tracking using superposition of merit functions. Proc SPIE 7266: 72661C-72661 - 77266C-72612.
[7]
Yemini E, Kerr RA, Schafer WR (2011) Tracking movement behavior of multiple worms on food. Cold Spring Harb Protoc 2011: 1483–1487.
[8]
Ramot D, Johnson BE, Berry TL Jr, Carnell L, Goodman MB (2008) The Parallel Worm Tracker: a platform for measuring average speed and drug-induced paralysis in nematodes. PLoS One 3: e2208.
[9]
Swierczek NA, Giles AC, Rankin CH, Kerr RA (2011) High-throughput behavioral analysis in C. elegans. Nat Methods 8: 592–598.
[10]
Albrecht DR, Bargmann CI (2011) High-content behavioral analysis of Caenorhabditis elegans in precise spatiotemporal chemical environments. Nat Methods 8: 599–605.
[11]
Contreras EQ, Cho M, Zhu H, Puppala HL, Escalera G, et al. (2013) Toxicity of quantum dots and cadmium salt to Caenorhabditis elegans after multigenerational exposure. Environ Sci Technol 47: 1148–1154.
[12]
Qi YB, Garren EJ, Shu X, Tsien RY, Jin Y (2012) Photo-inducible cell ablation in Caenorhabditis elegans using the genetically encoded singlet oxygen generating protein miniSOG. Proc Natl Acad Sci U S A 109: 7499–7504.
[13]
Wen Q, Po MD, Hulme E, Chen S, Liu X, et al. (2012) Proprioceptive coupling within motor neurons drives C. elegans forward locomotion. Neuron 76: 750–761.
[14]
Lee J, Li W, Guan KL (2005) SRC-1 mediates UNC-5 signaling in Caenorhabditis elegans. Mol Cell Biol 25: 6485–6495.
[15]
Faumont S, Rondeau G, Thiele TR, Lawton KJ, McCormick KE, et al. (2011) An image-free opto-mechanical system for creating virtual environments and imaging neuronal activity in freely moving Caenorhabditis elegans. PLoS One 6: e24666.
[16]
Kawano T, Po MD, Gao S, Leung G, Ryu WS, et al. (2011) An imbalancing act: gap junctions reduce the backward motor circuit activity to bias C. elegans for forward locomotion. Neuron 72: 572–586.
[17]
Piggott BJ, Liu J, Feng Z, Wescott SA, Xu XZ (2011) The neural circuits and synaptic mechanisms underlying motor initiation in C. elegans. Cell 147: 922–933.
[18]
Sellings L, Pereira S, Qian C, Dixon-McDougall T, Nowak C, et al. (2013) Nicotine-motivated behavior in Caenorhabditis elegans requires the nicotinic acetylcholine receptor subunits acr-5 and acr-15. Eur J Neurosci 37: 743–756.
[19]
Silva MC, Fox S, Beam M, Thakkar H, Amaral MD, et al. (2011) A genetic screening strategy identifies novel regulators of the proteostasis network. PLoS Genet 7: e1002438.
[20]
Stephens GJ, Johnson-Kerner B, Bialek W, Ryu WS (2008) Dimensionality and dynamics in the behavior of C. elegans. PLoS Comput Biol 4: e1000028.
[21]
Stirman JN, Crane MM, Husson SJ, Wabnig S, Schultheis C, et al. (2011) Real-time multimodal optical control of neurons and muscles in freely behaving Caenorhabditis elegans. Nat Methods 8: 153–158.
[22]
Kim H, Pierce-Shimomura JT, Oh HJ, Johnson BE, Goodman MB, et al. (2009) The dystrophin complex controls BK channel localization and muscle activity in Caenorhabditis elegans. PLoS Genet 5: e1000780.
[23]
Chen B, Liu P, Zhan H, Wang ZW (2011) Dystrobrevin Controls Neurotransmitter Release and Muscle Ca2+ Transients by Localizing BK Channels in Caenorhabditis elegans. J Neurosci 31: 17338–17347.
[24]
Chen B, Liu P, Wang SJ, Ge Q, Zhan H, et al. (2010) α-Catulin CTN-1 is required for BK channel subcellular localization in C. elegans body-wall muscle cells. EMBO J 29: 3184–3195.
[25]
Chen B, Ge Q, Xia XM, Liu P, Wang SJ, et al. (2010) A novel auxiliary subunit critical to BK channel function in Caenorhabditis elegans. J Neurosci 30: 16651–16661.
[26]
Ben Arous J, Tanizawa Y, Rabinowitch I, Chatenay D, Schafer WR (2010) Automated imaging of neuronal activity in freely behaving Caenorhabditis elegans. J Neurosci Methods 187: 229–234.
[27]
Huang KM, Cosman P, Schafer WR (2006) Machine vision based detection of omega bends and reversals in C. elegans. J Neurosci Methods 158: 323–336.
[28]
Kwon N, Pyo J, Lee SJ, Je JH (2013) 3-D worm tracker for freely moving C. elegans. PLoS One 8: e57484.
