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Movies |
Modeling the Neural Control of Zebrafish Locomotive Behaviors
Scott A. Hill, Xiao-Ping Liu, Melissa A.
Borla, Jorge V. José, and Donald M. O'Malley
Larval zebrafish exhibit a sophisticated locomotive repertoire
which depends on neural control signals that descend from brainstem to
spinal cord (Budick and O'Malley, 2000; Borla et al., 2002). Because
of the complexity of the descending motor control system in brainstem
(O'Malley et al., 2003) and the complexity of the spinal networks that
receive and respond to descending signals (Hale et al., 2001), it is
difficult to learn the nature of the controls that shape larval
locomotive behaviors (which include: routine turns, escape behaviors,
prey-tracking and prey capture). We have therefore turned to modeling
of both the kinematics of the animal's behaviors and the underlying
neural networks. Our goal is to understand how the complex locomotive
maneuvers exhibited by these larvae are generated.
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Simulations of
molecular motors
Frank Gibbons, J-F. Chauwin, and Jorge José
The simulations here recreate attempt to model the work of Howard et al.
(Nature, 1989). In their gliding assay experiment, they coated a microscope slide with
kinesin (which we show as little green dots), causing the tail-domains to stick to
the surface. A microtubule (the stick-like object) was then dropped onto the surface,
and propelled along by the action of the motors.
Howard et al. studied the speed of this translation as a function of the density of
motors attached to the slide, and found that it was more or less constant, over several
orders of magnitude. Because the microtubule has a polarity, I have indicated the plus
end in some of the newer movies. The kinesins try to move towards this end, which means
the other (`minus') end leads.
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