![]() A platform at its center supported the agar disc such that all but its top surface was immersed in a bath solution with the same salt and glycerol concentrations as the disc. ![]() The experimental apparatus resembled a two-axis gel electrophoresis chamber. elegans nervous system converts sensory perception into motor behavior. Our results establish electrosensory behavior as a new framework for studying how the C. elegans nervous system on electrosensory behavior, and quantified electrosensory detection among the amphid sensory neurons by imaging intracellular calcium dynamics. In this study, we analyzed the movements of individual worms navigating fixed and time-varying electric fields across a wide range of stimulus parameters, quantified the effects of specific genetic and physical perturbations to the C. ![]() elegans as they crawled toward the negative poles of an electric field, but they neither quantified the physical determinants of electrotaxis (also called galvanotaxis) nor determined whether electrotaxis has a neural basis. Sukul and Croll (1978) noted the strikingly straight trajectories of wild-type C. Here, we focus on electrosensory behavior, another case of direct steering. For example, when the worm navigates thermal gradients at temperatures near its previous cultivation temperature, it tends to crawl along isotherms in single prolonged runs ( Hedgecock and Russell, 1975 Luo et al., 2006). elegans is also capable of direct steering. This strategy is called the biased random walk. When it happens to be oriented toward declining conditions, it shortens runs. When the worm happens to be oriented toward improving conditions, it prolongs runs. elegans navigates sensory gradients during chemotaxis or thermotaxis based on random trial-and-error ( Pierce-Shimomura et al., 1999 Ryu and Samuel, 2002). elegans motility may be characterized as periods of forward movement (runs) that are interrupted by reorientation maneuvers (turns and reversals) ( Croll, 1975). The neural basis of navigational behavior may be approachable in the nematode Caenorhabditis elegans, as sensory detection, behavioral choice, and motor output are regulated by a small 302-neuron nervous system. At the motor level, an organism may have to decide between different types of movements in response to the same sensory inputs an example is the leech for which triggering movement necessitates the choice between crawling movement or swimming movement ( Esch et al., 2002). For instance, at the sensory level, an organism may have to integrate time-varying sensory inputs with its own movements to infer its own orientation an example is Escherichia coli chemotaxis, in which the bacterium processes temporal changes in ambient chemical concentration during periods of its own forward movement to decide whether it is swimming toward or away from nutrients ( Berg and Brown, 1972). However, the neural circuits that guide navigation are less understood, because complexities may arise at each level from sensory input to motor output. In a few cases, it has been possible to map feedforward circuits that encode reflexive responses, such as gill withdrawal in Aplysia or touch avoidance in the nematode ( Kupfermann and Kandel, 1969 Chalfie et al., 1985). The major function of the nervous system is to transform sensory inputs into motor outputs, ranging in sophistication from simple reflexive responses to navigation in variable environments. Thus, electrosensory behavior may be used as a model system for understanding how sensory inputs are transformed into motor outputs by the C. ![]() We extend our analysis to the motor level by showing that specific interneurons affect the utilization of sudden turns and reversals during electrosensory steering. ![]() By imaging intracellular calcium dynamics among the amphid sensory neurons of immobilized worms, we show that specific amphid sensory neurons are sensitive to the direction and strength of electric fields. Mutation or laser ablation that disrupts the structure and function of amphid sensory neurons also disrupts electrosensory behavior. elegans uses during other modes of motile behavior. elegans reorients itself in response to time-varying electric fields by using sudden turns and reversals, standard reorientation maneuvers that C. elegans prefers to crawl at specific angles to the direction of the electric field in persistent periods of forward movement and that the preferred angle is proportional to field strength. By quantifying the movements of individual worms navigating electric fields, we show that C. The nematode Caenorhabditis elegans deliberately crawls toward the negative pole in an electric field. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |