The S cell: An interneuron essential for sensitization and full dishabituation of leech shortening

Christie L. Sahley, Barbara K. Modney, Nicholas M. Boulis, Kenneth J Muller

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Abstract

Sensory neurons in the leech excite the S interneuron, which in turn excites motoneurons that shorten the leech, although activity in the S cell reportedly cannot by itself shorten the animal. Experiments were performed in semi-intact leeches using established dishabituation and sensitization protocols. S-cell activity increased during reflexive shortening once the animal was sensitized or dishabituated with a strong shock. S-cell activity otherwise was not associated with shortening. To test the role of the S-cell in dishabituation and sensitization of the shortening reflex, single S cells were ablated in vivo by intracellular injections of pronase. S-cell lesions reduced but did not eliminate dishabituation; however, sensitization was completely disrupted. This was consistent with recent evidence that separate processes contribute to dishabituation and sensitization. Since the S cell in each ganglion is a link in a rapidly conducting chain along the length of the animal, it may be sufficient to break the chain at a single point to eliminate sensitization.

Original languageEnglish
Pages (from-to)6715-6721
Number of pages7
JournalJournal of Neuroscience
Volume14
Issue number11 I
StatePublished - Nov 15 1994

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Keywords

  • dishabituation
  • learning
  • leech
  • S-cell
  • S-cell ablation
  • sensitization

ASJC Scopus subject areas

  • Neuroscience(all)

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