Feeding neural networks in the mollusc Aplysia

Neurosignals. 2004 Jan-Apr;13(1-2):70-86. doi: 10.1159/000076159.


Aplysia feeding is striking in that it is executed with a great deal of plasticity. At least in part, this flexibility is a result of the organization of the feeding neural network. To illustrate this, we primarily discuss motor programs triggered via stimulation of the command-like cerebral-buccal interneuron 2 (CBI-2). CBI-2 is interesting in that it can generate motor programs that serve opposing functions, i.e., programs can be ingestive or egestive. When programs are egestive, radula-closing motor neurons are activated during the protraction phase of the motor program. When programs are ingestive, radula-closing motor neurons are activated during retraction. When motor programs change in nature, activity in the radula-closing circuitry is altered. Thus, CBI-2 stimulation stereotypically activates the protraction and retraction circuitry, with protraction being generated first, and retraction immediately thereafter. In contrast, radula-closing motor neurons can be activated during either protraction or retraction. Which will occur is determined by whether other cerebral and buccal neurons are recruited, e.g. radula-closing motor neurons tend to be activated during retraction if a second CBI, CBI-3, is recruited. Fundamentally different motor programs are, therefore, generated because CBI-2 activates some interneurons in a stereotypic manner and other interneurons in a variable manner.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Aplysia / physiology*
  • Behavior, Animal
  • Digestive System Physiological Phenomena
  • Feedback
  • Feeding Behavior / physiology*
  • Ganglia, Invertebrate / cytology
  • Ganglia, Invertebrate / physiology
  • Motor Activity
  • Nerve Net / cytology
  • Nerve Net / physiology*
  • Neural Inhibition
  • Neural Networks, Computer
  • Neurons / classification
  • Neurons / physiology*