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6 Mouse?
Current Biology
Dispatches Behavioral Neuroscience: Who’s Afraid of the C57BL/6 Mouse? Damian J. Wallace and Jason N.D. Kerr Department of Behavior and Brain Organization, research center caesar, Bonn, Germany Correspondence: [email protected] (D.J.W.), [email protected] (J.N.D.K.) http://dx.doi.org/10.1016/j.cub.2016.09.047
Behavioral paradigms in which laboratory rodents express behaviors that their wild counterparts presumably need every day are rare: a novel prey-capture model for laboratory mice has been developed for examining the neurophysiological underpinnings of prey capture in mice. Who’s afraid of the C57/BL6 mouse? Crickets, as it turns out. In this issue of Current Biology, a paper by Hoy et al. [1] describes an interesting set of experiments demonstrating firstly that laboratory mice will readily and vigorously consume live insect prey, but also that a prey-capture behavior presents an excellent paradigm for examining the functioning of the visual pathway during an ethologically relevant behavior. Rodents, particularly mice and rats, are widely used as model organisms for studies of the visual system [2]. However, the tools, tasks and tests used for studying vision in mice were developed largely for investigating the visual systems of animals with vastly different visual capabilities, such as primates and cats, which evolved to occupy very different ecological niches. Many of these basic visual stimuli and visually based behavioral tasks have been, and continue to be, used to generate data that are central to our understanding of the mammalian visual system. Further, the basic properties of visually responsive neurons revealed by such stimuli are conserved across many animal species. In fact, one of the most notable aspects of the published findings on the visual systems of these very different species is just how similar the response characteristics are of individual neurons in the primary visual cortex [3–6]. Behavioral tasks for studying the visual system in rodents need to take account of the differences in visual system design and function between rodents and primates or cats. For example, while primates have frontally facing eyes, conjugate eye movements, trichromatic
color vision, high spatial acuity and excellent stereoscopic binocular vision, rodents have about an order of magnitude lower spatial acuity, dichromatic color vision with their ‘blue’ cones shifted into the ultraviolet range and disconjugate eye movements when freely moving [7]. Furthermore, their eyes are located on the side of the animal’s head, pointing 50–60 degrees laterally from frontal and about 30–40 degrees up [8]. The overlap of the left and right eye visual fields spans an area from below the snout to behind the head, and thanks to the large visual field of each eye (thought to be 200 degrees) they have, like many animals with non-frontally facing eyes, a near panoramic view of the world around them. As these rodent species are highly successful generalists, managing to avoid predation and find shelter, food and mates in a wide variety of environments world-wide [9], a logical and attractive option is to develop behavioral tasks related to behaviors that their wild relatives may use on a regular basis. One example is escape behavior. Rodents generally have to face a tradeoff between foraging in open areas where food is available and avoidance of predation, particularly from airborne predators. Escape behaviors appear to be innate and can be evoked in a laboratory setting [7,10] and are, therefore, one option for behavioral tasks. As mice and rats are both generalist omnivores [11–13], prey capture is another interesting behavior to explore. Hoy et al. [1], in a relatively simple but thought-provoking study, describe a series of experiments examining the role of vision in prey capture in laboratory mice.
R1188 Current Biology 26, R1177–R1196, November 21, 2016 ª 2016 Elsevier Ltd.
Hoy et al. [1] begin by demonstrating that C57BL/6 laboratory mice vigorously and robustly capture and eat live insects, in particular crickets. This prey-capture behavior was displayed spontaneously by almost all individuals (97%). By conducting experiments in normal light, in darkness, with animals with surgically implanted ear plugs and in darkness with ear plugs, the authors could show that, while auditory information alone could be used by the mice to capture prey, vision was required for localization of the insect and for maintaining the animal’s heading towards the insect during approach. Animals in the dark and in the absence of hearing were essentially unable to capture prey. Finally, mice were able to locate and approach insects that were located behind a transparent acrylic barrier using similar approach and attack behaviors as they used in the open arena. This allowed greater control of the multisensory cues available to the animal by also allowing manipulation of olfactory cues and presumably eliminating whisking-based information. Another line of thought for experiments in the visual system is to use complex movie segments, such as those collected from a head-mounted camera, as the visual stimulus. These very rich stimuli, perhaps not surprisingly, result in very different patterns of activity in the visual system from patterns evoked by the more classic but simple stimuli. But they can never match the complexity that self-derived movements present and most importantly there is no control of the visual scene by the animal and therefore the relationship between the presented scene and the vestibular system is broken. The behavioral task described by Hoy et al. [1] overcomes
Current Biology
Dispatches these issues. First, the animal is free to do what it pleases while performing a seemingly innate behavior. Second, all the animal’s systems for image stabilization and interaction with the environment during movement, target selection, and processing of the image of the target are available. Finally, the animal is highly motivated to catch and eat the prey. With continued miniaturization of recording devices for neuroscience, from silicon probes with combined miniaturized LEDs or light guides for optogenetic stimulation [14,15], to amplifiers for electrophysiological recording [16–18], to multiphoton microscopes [19] and systems for tracking eye position and head position and orientation in freely moving rodents [7], it is now feasible to measure many relevant parameters required to investigate the activity of cortical networks while animals are performing this prey-capture behavioral paradigm. Indeed this prey-capture behavior has tremendous potential to reveal new insights into the function of the rodent visual system operating as it was evolved to work. REFERENCES 1. Hoy, J.L., Yavorska, I., Wehr, M., and Niell, C.M. (2016). Vision drives accurate
approach behavior during prey capture in laboratory mice. Curr. Biol. 26, 3046–3052. 2. Huberman, A.D., and Niell, C.M. (2011). What can mice tell us about how vision works? Trends Neurosci. 34, 464–473. 3. Drager, U.C. (1975). Receptive fields of single cells and topography in mouse visual cortex. J. Comp. Neurol. 160, 269–290. 4. Hubel, D.H., and Wiesel, T.N. (1959). Receptive fields of single neurones in the cat’s striate cortex. J. Physiol. 148, 574–591. 5. Hubel, D.H., and Wiesel, T.N. (1968). Receptive fields and functional architecture of monkey striate cortex. J. Physiol. 195, 215–243. 6. Parnavelas, J.G., Burne, R.A., and Lin, C.S. (1981). Receptive field properties of neurons in the visual cortex of the rat. Neurosci. Lett. 27, 291–296. 7. Wallace, D.J., Greenberg, D.S., Sawinski, J., Rulla, S., Notaro, G., and Kerr, J.N. (2013). Rats maintain an overhead binocular field at the expense of constant fusion. Nature 498, 65–69. 8. Hughes, A. (1979). A schematic eye for the rat. Vision Res. 19, 569–588. 9. Boursot, P., Auffray, J.C., Brittondavidian, J., and Bonhomme, F. (1993). The evolution of house mice. Annu. Rev. Ecol. Syst. 24, 119–152. 10. Yilmaz, M., and Meister, M. (2013). Rapid innate defensive responses of mice to looming visual stimuli. Curr. Biol. 23, 2011–2015. 11. Badan, D. (1986). Diet of the house mouse (Mus-musculus L) in 2 pine and a kauri forest. New Zeal. J. Ecol. 9, 137–141.
12. Clark, D.D. (1982). Foraging behavior of a vertebrate omnivore (Rattus rattus): meal structure, sampling, and diet breadth. Ecology 63, 763–772. 13. Rogers, L.M., and Gorman, M.L. (1995). The diet of the wood mouse Apodemus-sylvaticus on set-aside land. J. Zool. 235, 77–83. 14. Buzsa´ki, G., Stark, E., Bere´nyi, A., Khodagholy, D., Kipke, D.R., Yoon, E., and Wise, K. (2015). Tools for probing local circuits: high-density silicon probes combined with optogenetics. Neuron 86, 92–105. 15. Shim, E., Chen, Y., Masmanidis, S., and Li, M. (2016). Multisite silicon neural probes with integrated silicon nitride waveguides and gratings for optogenetic applications. Sci. Rep. 6, 22693. 16. Haiss, F., Butovas, S., and Schwarz, C. (2010). A miniaturized chronic microelectrode drive for awake behaving head restrained mice and rats. J. Neurosci. Meth. 187, 67–72. 17. Ng, K.A., Greenwald, E., Xu, Y.P., and Thakor, N.V. (2016). Implantable neurotechnologies: a review of integrated circuit neural amplifiers. Med. Biol. Eng. Comput. 54, 45–62. 18. Park, S.I., Shin, G., Banks, A., McCall, J.G., Siuda, E.R., Schmidt, M.J., Chung, H.U., Noh, K.N., Mun, J.G., Rhodes, J., et al. (2015). Ultraminiaturized photovoltaic and radio frequency powered optoelectronic systems for wireless optogenetics. J. Neural Eng. 12, 056002. 19. Sawinski, J., Wallace, D.J., Greenberg, D.S., Grossmann, S., Denk, W., and Kerr, J.N. (2009). Visually evoked activity in cortical cells imaged in freely moving animals. Proc. Natl. Acad. Sci. USA 106, 19557–19562.
Evolution: When Dinosaurs Bested Their Early Rivals Stephen L. Brusatte School of GeoSciences, University of Edinburgh, Grant Institute, James Hutton Road, Edinburgh EH9 3FE, UK Correspondence: [email protected] http://dx.doi.org/10.1016/j.cub.2016.09.048
A sublime fossil discovery in Brazil shows that dinosaurs and their immediate evolutionary precursors lived together for tens of millions of years before dinosaurs ultimately rose to the top. Tyrannosaurus rex, Brontosaurus, Velociraptor — their names ring out like an advertising jingle, conjuring an image of big, powerful, fierce, dominant animals, the undisputed rulers of the prehistoric world. But dinosaurs weren’t always like this. As with any dynasty,
they started small and fought their way to the crown. For decades, scientists have debated how and why this happened. Were dinosaurs superior to their early competitors — somehow better endowed in their bodies or behaviors — or more lucky than good? Did they rise
up quickly or dispatch their rivals through a long war of attrition? A fantastic new fossil discovery from southern Brazil (Figure 1), described by Cabreira et al. [1] in this issue of Current Biology, gets at the heart of these questions by providing one of the clearest snapshots yet of how
Current Biology 26, R1177–R1196, November 21, 2016 ª 2016 Elsevier Ltd. R1189
Dispatches Behavioral Neuroscience: Who’s Afraid of the C57BL/6 Mouse? Damian J. Wallace and Jason N.D. Kerr Department of Behavior and Brain Organization, research center caesar, Bonn, Germany Correspondence: [email protected] (D.J.W.), [email protected] (J.N.D.K.) http://dx.doi.org/10.1016/j.cub.2016.09.047
Behavioral paradigms in which laboratory rodents express behaviors that their wild counterparts presumably need every day are rare: a novel prey-capture model for laboratory mice has been developed for examining the neurophysiological underpinnings of prey capture in mice. Who’s afraid of the C57/BL6 mouse? Crickets, as it turns out. In this issue of Current Biology, a paper by Hoy et al. [1] describes an interesting set of experiments demonstrating firstly that laboratory mice will readily and vigorously consume live insect prey, but also that a prey-capture behavior presents an excellent paradigm for examining the functioning of the visual pathway during an ethologically relevant behavior. Rodents, particularly mice and rats, are widely used as model organisms for studies of the visual system [2]. However, the tools, tasks and tests used for studying vision in mice were developed largely for investigating the visual systems of animals with vastly different visual capabilities, such as primates and cats, which evolved to occupy very different ecological niches. Many of these basic visual stimuli and visually based behavioral tasks have been, and continue to be, used to generate data that are central to our understanding of the mammalian visual system. Further, the basic properties of visually responsive neurons revealed by such stimuli are conserved across many animal species. In fact, one of the most notable aspects of the published findings on the visual systems of these very different species is just how similar the response characteristics are of individual neurons in the primary visual cortex [3–6]. Behavioral tasks for studying the visual system in rodents need to take account of the differences in visual system design and function between rodents and primates or cats. For example, while primates have frontally facing eyes, conjugate eye movements, trichromatic
color vision, high spatial acuity and excellent stereoscopic binocular vision, rodents have about an order of magnitude lower spatial acuity, dichromatic color vision with their ‘blue’ cones shifted into the ultraviolet range and disconjugate eye movements when freely moving [7]. Furthermore, their eyes are located on the side of the animal’s head, pointing 50–60 degrees laterally from frontal and about 30–40 degrees up [8]. The overlap of the left and right eye visual fields spans an area from below the snout to behind the head, and thanks to the large visual field of each eye (thought to be 200 degrees) they have, like many animals with non-frontally facing eyes, a near panoramic view of the world around them. As these rodent species are highly successful generalists, managing to avoid predation and find shelter, food and mates in a wide variety of environments world-wide [9], a logical and attractive option is to develop behavioral tasks related to behaviors that their wild relatives may use on a regular basis. One example is escape behavior. Rodents generally have to face a tradeoff between foraging in open areas where food is available and avoidance of predation, particularly from airborne predators. Escape behaviors appear to be innate and can be evoked in a laboratory setting [7,10] and are, therefore, one option for behavioral tasks. As mice and rats are both generalist omnivores [11–13], prey capture is another interesting behavior to explore. Hoy et al. [1], in a relatively simple but thought-provoking study, describe a series of experiments examining the role of vision in prey capture in laboratory mice.
R1188 Current Biology 26, R1177–R1196, November 21, 2016 ª 2016 Elsevier Ltd.
Hoy et al. [1] begin by demonstrating that C57BL/6 laboratory mice vigorously and robustly capture and eat live insects, in particular crickets. This prey-capture behavior was displayed spontaneously by almost all individuals (97%). By conducting experiments in normal light, in darkness, with animals with surgically implanted ear plugs and in darkness with ear plugs, the authors could show that, while auditory information alone could be used by the mice to capture prey, vision was required for localization of the insect and for maintaining the animal’s heading towards the insect during approach. Animals in the dark and in the absence of hearing were essentially unable to capture prey. Finally, mice were able to locate and approach insects that were located behind a transparent acrylic barrier using similar approach and attack behaviors as they used in the open arena. This allowed greater control of the multisensory cues available to the animal by also allowing manipulation of olfactory cues and presumably eliminating whisking-based information. Another line of thought for experiments in the visual system is to use complex movie segments, such as those collected from a head-mounted camera, as the visual stimulus. These very rich stimuli, perhaps not surprisingly, result in very different patterns of activity in the visual system from patterns evoked by the more classic but simple stimuli. But they can never match the complexity that self-derived movements present and most importantly there is no control of the visual scene by the animal and therefore the relationship between the presented scene and the vestibular system is broken. The behavioral task described by Hoy et al. [1] overcomes
Current Biology
Dispatches these issues. First, the animal is free to do what it pleases while performing a seemingly innate behavior. Second, all the animal’s systems for image stabilization and interaction with the environment during movement, target selection, and processing of the image of the target are available. Finally, the animal is highly motivated to catch and eat the prey. With continued miniaturization of recording devices for neuroscience, from silicon probes with combined miniaturized LEDs or light guides for optogenetic stimulation [14,15], to amplifiers for electrophysiological recording [16–18], to multiphoton microscopes [19] and systems for tracking eye position and head position and orientation in freely moving rodents [7], it is now feasible to measure many relevant parameters required to investigate the activity of cortical networks while animals are performing this prey-capture behavioral paradigm. Indeed this prey-capture behavior has tremendous potential to reveal new insights into the function of the rodent visual system operating as it was evolved to work. REFERENCES 1. Hoy, J.L., Yavorska, I., Wehr, M., and Niell, C.M. (2016). Vision drives accurate
approach behavior during prey capture in laboratory mice. Curr. Biol. 26, 3046–3052. 2. Huberman, A.D., and Niell, C.M. (2011). What can mice tell us about how vision works? Trends Neurosci. 34, 464–473. 3. Drager, U.C. (1975). Receptive fields of single cells and topography in mouse visual cortex. J. Comp. Neurol. 160, 269–290. 4. Hubel, D.H., and Wiesel, T.N. (1959). Receptive fields of single neurones in the cat’s striate cortex. J. Physiol. 148, 574–591. 5. Hubel, D.H., and Wiesel, T.N. (1968). Receptive fields and functional architecture of monkey striate cortex. J. Physiol. 195, 215–243. 6. Parnavelas, J.G., Burne, R.A., and Lin, C.S. (1981). Receptive field properties of neurons in the visual cortex of the rat. Neurosci. Lett. 27, 291–296. 7. Wallace, D.J., Greenberg, D.S., Sawinski, J., Rulla, S., Notaro, G., and Kerr, J.N. (2013). Rats maintain an overhead binocular field at the expense of constant fusion. Nature 498, 65–69. 8. Hughes, A. (1979). A schematic eye for the rat. Vision Res. 19, 569–588. 9. Boursot, P., Auffray, J.C., Brittondavidian, J., and Bonhomme, F. (1993). The evolution of house mice. Annu. Rev. Ecol. Syst. 24, 119–152. 10. Yilmaz, M., and Meister, M. (2013). Rapid innate defensive responses of mice to looming visual stimuli. Curr. Biol. 23, 2011–2015. 11. Badan, D. (1986). Diet of the house mouse (Mus-musculus L) in 2 pine and a kauri forest. New Zeal. J. Ecol. 9, 137–141.
12. Clark, D.D. (1982). Foraging behavior of a vertebrate omnivore (Rattus rattus): meal structure, sampling, and diet breadth. Ecology 63, 763–772. 13. Rogers, L.M., and Gorman, M.L. (1995). The diet of the wood mouse Apodemus-sylvaticus on set-aside land. J. Zool. 235, 77–83. 14. Buzsa´ki, G., Stark, E., Bere´nyi, A., Khodagholy, D., Kipke, D.R., Yoon, E., and Wise, K. (2015). Tools for probing local circuits: high-density silicon probes combined with optogenetics. Neuron 86, 92–105. 15. Shim, E., Chen, Y., Masmanidis, S., and Li, M. (2016). Multisite silicon neural probes with integrated silicon nitride waveguides and gratings for optogenetic applications. Sci. Rep. 6, 22693. 16. Haiss, F., Butovas, S., and Schwarz, C. (2010). A miniaturized chronic microelectrode drive for awake behaving head restrained mice and rats. J. Neurosci. Meth. 187, 67–72. 17. Ng, K.A., Greenwald, E., Xu, Y.P., and Thakor, N.V. (2016). Implantable neurotechnologies: a review of integrated circuit neural amplifiers. Med. Biol. Eng. Comput. 54, 45–62. 18. Park, S.I., Shin, G., Banks, A., McCall, J.G., Siuda, E.R., Schmidt, M.J., Chung, H.U., Noh, K.N., Mun, J.G., Rhodes, J., et al. (2015). Ultraminiaturized photovoltaic and radio frequency powered optoelectronic systems for wireless optogenetics. J. Neural Eng. 12, 056002. 19. Sawinski, J., Wallace, D.J., Greenberg, D.S., Grossmann, S., Denk, W., and Kerr, J.N. (2009). Visually evoked activity in cortical cells imaged in freely moving animals. Proc. Natl. Acad. Sci. USA 106, 19557–19562.
Evolution: When Dinosaurs Bested Their Early Rivals Stephen L. Brusatte School of GeoSciences, University of Edinburgh, Grant Institute, James Hutton Road, Edinburgh EH9 3FE, UK Correspondence: [email protected] http://dx.doi.org/10.1016/j.cub.2016.09.048
A sublime fossil discovery in Brazil shows that dinosaurs and their immediate evolutionary precursors lived together for tens of millions of years before dinosaurs ultimately rose to the top. Tyrannosaurus rex, Brontosaurus, Velociraptor — their names ring out like an advertising jingle, conjuring an image of big, powerful, fierce, dominant animals, the undisputed rulers of the prehistoric world. But dinosaurs weren’t always like this. As with any dynasty,
they started small and fought their way to the crown. For decades, scientists have debated how and why this happened. Were dinosaurs superior to their early competitors — somehow better endowed in their bodies or behaviors — or more lucky than good? Did they rise
up quickly or dispatch their rivals through a long war of attrition? A fantastic new fossil discovery from southern Brazil (Figure 1), described by Cabreira et al. [1] in this issue of Current Biology, gets at the heart of these questions by providing one of the clearest snapshots yet of how
Current Biology 26, R1177–R1196, November 21, 2016 ª 2016 Elsevier Ltd. R1189