4 research outputs found
Recommended from our members
Thermal navigation in larval zebrafish
Navigation in complex environments requires selection of appropriate actions as a function of local cues. To gain a quantitative and mechanistic understanding of zebrafish thermal navigation, we have developed a novel assay that requires animals to rely exclusively on thermosensory information in the absence of other cues such as vision or mechanosensation. We show that zebrafish use both absolute and relative temperature information to restrict their locomotor trajectories to a preferred temperature range. We identify components of movement that are modulated solely by absolute temperature, as well as components that are modulated by both absolute and relative temperature. Specifically, we find that dwell time between movements and displacement per movement depend solely on absolute temperature, whereas turn magnitude and turn direction bias are modulated by absolute and relative temperature. To evaluate whether these sensorimotor relationships could explain thermal restriction in our navigation assay, we performed Monte Carlo simulations of locomotor trajectories based on all or subsets of these relationships. We find that thermosensory modulation of turn magnitude and turn direction bias constitute the core navigation strategy in larval zebrafish, while modulation of dwell time accelerates the execution of this strategy at noxious temperatures. Modulation of turn direction bias represents a novel strategy not found in invertebrate models, whereby animals correct unfavorable headings by preferentially turning in a preferred turn direction until they obtain a favorable heading. Modulating turn direction bias in response to recent sensory experience is an effective strategy for selecting favorable headings in organisms that do not have a dedicated sampling phase before each reorientation event
Recommended from our members
The Tangential Nucleus Controls a Gravito-inertial Vestibulo-ocular Reflex
Whilst adult vertebrates sense changes in head position using two classes of accelerometer, at larval stages zebrafish lack functional semicircular canals and rely exclusively on their otolithic organs to transduce vestibular information. Despite this limitation, they perform an effective vestibulo-ocular reflex (VOR) that serves to stabilize gaze in response to pitch and roll tilts. Using single-cell electroporations and targeted laser-ablations, we identified a specific class of central vestibular neurons, located in the tangential nucleus, which are essential for the utricle-dependent VOR. Tangential nucleus neurons project contralaterally to extraocular motoneurons, and in addition, to multiple sites within the reticulospinal complex. We propose that tangential neurons function as a broadband inertial accelerometer, processing utricular acceleration signals to control the activity of extraocular and postural neurons, thus completing a fundamental three-neuron circuit responsible for gaze stabilization.Molecular and Cellular Biolog
Teaching Bioeconomics
Bioeconomics is a relatively young field that uses an expanded microeconomics to examine animal behavior, human behavior, and animal and human social institutions. A voluminous literature is rapidly accumulating. There are as yet no standard textbooks, but there are several excellent books and/or articles that can be used in combination with videos and other aids to make a course that students will enjoy and that teachers can use to advance the frontiers of scholarship in economics and biology. Copyright Springer 2005altruism, conflict, cooperation, evolution, game theory, institutions, rationality,