Skip to main content
Log in

Functionally heterogeneous segmental oscillators generate swimming in the medicinal leech

  • Original paper
  • Published:
Journal of Comparative Physiology A Aims and scope Submit manuscript

Abstract.

Swimming behavior in the leech Hirudo medicinalis arises from neuronal circuits within the ventral nerve cord. Although the ventral nerve cord comprises a series of homologous segmental ganglia, it remains unresolved whether the swim oscillator circuits within individual ganglia are functionally equivalent. We have extended previous studies on pairs of ganglia to test whether individual ganglia throughout the nerve cord are capable of generating swim oscillations and to measure the cycle periods of local oscillations. We found that the swim-generating function of individual ganglia is broadly distributed, but not uniform. The swim-like oscillations in isolated ganglia from the anterior ganglia nerve cord were less robust than those from mid-cord. Swimming activity in posterior cord ganglia is even weaker – we were unable to obtain swim-like oscillations from individual ganglia of the nerve cord posterior to segment 12. Swim-cycle periods exhibited a U-shaped function: those recorded in the most anterior individual ganglia (2.3 s for ganglion M2) and short chains of posterior ganglia (up to 4.0 s) were two to four times longer than those obtained from mid-cord ganglia (near 1.0 s). We conclude that the leech swim system comprises a functionally heterogeneous set of local oscillator units.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Author information

Authors and Affiliations

Authors

Additional information

Electronic Publication

Rights and permissions

Reprints and permissions

About this article

Cite this article

Hocker, C., Yu, X. & Friesen, W. Functionally heterogeneous segmental oscillators generate swimming in the medicinal leech. J Comp Physiol A 186, 871–883 (2000). https://doi.org/10.1007/s003590000140

Download citation

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s003590000140

Navigation