Learning Hesitation

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Science  21 Jun 2002:
Vol. 296, Issue 5576, pp. 2105
DOI: 10.1126/science.296.5576.2105c

Ishihara et al. have studied how neuronal circuits manage integration of multiple signals in Caenorhabditis elegans, whose simple nervous system contains 302 neurons. Wild-type animals are attracted to the odorant diacetyl and repulsed by Cu2+. Normally, avoidance of Cu2+ can be suppressed by the presence of diacetyl, but, in hen-1 mutants, diacetyl was less effective in luring the animals across a barrier of Cu2+. In the absence of Cu2+, hen-1 mutants were equally sensitive to the attractant properties of diacetyl, but hen-1 mutants were less sensitive than wild-type animals to Cu2+ as an inhibitor of chemotaxis toward diacetyl. Thus, the defect seems to lie in the association of the two signals. In a second behavioral assay using NaCl and starvation, hen-1 mutants were again less sensitive to interacting signals. The HEN-1 protein appears to be a secreted protein and may function as a neuromodulator, like the peptide FMRFamide. — LBR

Cell109, 639 (2002).

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