%0 Journal Article
%T Phase-dependent preference of thermosensation and chemosensation during simultaneous presentation assay in Caenorhabditis elegans
%A Ryota Adachi
%A Hiroshi Osada
%A Ryuzo Shingai
%J BMC Neuroscience
%D 2008
%I BioMed Central
%R 10.1186/1471-2202-9-106
%X We studied the behavior of a population of C. elegans during simultaneous presentation of thermal and chemical stimuli. First, we examined thermotaxis within the radial temperature gradient produced by a feedback-controlled thermoregulator. Separately, we examined chemotaxis toward sodium chloride or isoamyl alcohol. Then, assays for simultaneous presentations of 15ˇăC (colder temperature than 20ˇăC room temperature) and chemoattractant were performed with 15ˇăC-cultivated wild-type worms. Unlike the sum of behavioral indices for each separate behavior, simultaneous presentation resulted in a biased migration to cold regions in the first 10 min of the assay, and sodium chloride-regions in the last 40 min. However, when sodium chloride was replaced with isoamyl alcohol in the simultaneous presentation, the behavioral index was very similar to the sum of separate single presentation indices. We then recorded tracks of single worms and analyzed their behavior. For behavior toward sodium chloride, frequencies of forward and backward movements in simultaneous presentation were significantly different from those in single presentation. Also, migration toward 15ˇăC in simultaneous presentation was faster than that in 15ˇăC-single presentation.We conclude that worms preferred temperature to chemoattractant at first, but preferred the chemoattractant sodium chloride thereafter. This preference was not seen for isoamyl alcohol presentation. We attribute this phase-dependent preference to the result of integration of thermosensory and chemosensory signals received by distinct sensory neurons.While awake, animals detect multiple sensory cues such as chemical and physical stimuli. The variety of sensory information in the environment requires integration of multiple cues within an animal's nervous system. Due to their complexity, neuronal mechanisms that support the multi-sensory integration are difficult to study. The anatomically characterized and compact nervous system of Caenorha
%U http://www.biomedcentral.com/1471-2202/9/106