@article{oai:iwate-u.repo.nii.ac.jp:00009713,
 author = {Adachi, Ryota and Osada, Hiroshi and Shingai, Ryuzo},
 issue = {106},
 journal = {BMC Neuroscience},
 month = {Jan},
 note = {Background: Multi-sensory integration is necessary for organisms to discriminate different
environmental stimuli and thus determine behavior. Caenorhabditis elegans has 12 pairs of amphid
sensory neurons, which are involved in generating behaviors such as thermotaxis toward
cultivation temperature, and chemotaxis toward chemical stimuli. This arrangement of known
sensory neurons and measurable behavioral output makes C. elegans suitable for addressing
questions of multi-sensory integration in the nervous system. Previous studies have suggested that
C. elegans can process different chemoattractants simultaneously. However, little is known about
how these organisms can integrate information from stimuli of different modality, such as thermal
and chemical stimuli.

Results: 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 15°C
(colder temperature than 20°C room temperature) and chemoattractant were performed with
15°C-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 15°C in simultaneous presentation was faster than that in
15°C-single presentation.

Conclusion: 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.},
 pages = {1--15},
 title = {Phase-dependent preference of thermosensation and chemosensation during simultaneous presentation assay in Caenorhabditis elegans},
 volume = {9},
 year = {2008}
}