Relationships between Bilateral Circadian Pacemakers in Intact and Neurally Separated Optic-Lobes of a Carabid Beetle

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4 Citations (Scopus)

Abstract

The mutual interactions between the bilaterally-paired optic-lobe circadian pacemakers in the carabid beetle, Carabus insulicola insulicola, were investigated by recording electroretinograms (ERGs) under constant darkness. The ERG amplitudes of both right and left compound eyes exhibited clear circadian rhythms due to direct efferent controls from the ipsilateral optic-lobe pacemakers. In the free-running state, the circadian period of the two pacemakers in each beetle ran parallel to each other. The phase-angle difference between the two pacemakers was generally close to 0° but we found that the two-oscillator system also stabilizes with phase-angles of 90°, 180° and 270°. Unilateral severance of the optic tract resulted in increased free-running period lengths of both the ipsilateral and contralateral pacemakers, indicating that the mutual neural interactions shorten the period.

Original languageEnglish (US)
Pages (from-to)537-542
Number of pages6
JournalApplied Entomology and Zoology
Volume30
Issue number4
DOIs
StatePublished - 1995

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optic lobe
electroretinography
Coleoptera
compound eyes
optics
circadian rhythm

Keywords

  • Carabus
  • circadian rhythm
  • electroretinogram
  • pacemaker coupling
  • phase-angle difference

ASJC Scopus subject areas

  • Insect Science

Cite this

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title = "Relationships between Bilateral Circadian Pacemakers in Intact and Neurally Separated Optic-Lobes of a Carabid Beetle",
abstract = "The mutual interactions between the bilaterally-paired optic-lobe circadian pacemakers in the carabid beetle, Carabus insulicola insulicola, were investigated by recording electroretinograms (ERGs) under constant darkness. The ERG amplitudes of both right and left compound eyes exhibited clear circadian rhythms due to direct efferent controls from the ipsilateral optic-lobe pacemakers. In the free-running state, the circadian period of the two pacemakers in each beetle ran parallel to each other. The phase-angle difference between the two pacemakers was generally close to 0° but we found that the two-oscillator system also stabilizes with phase-angles of 90°, 180° and 270°. Unilateral severance of the optic tract resulted in increased free-running period lengths of both the ipsilateral and contralateral pacemakers, indicating that the mutual neural interactions shorten the period.",
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N2 - The mutual interactions between the bilaterally-paired optic-lobe circadian pacemakers in the carabid beetle, Carabus insulicola insulicola, were investigated by recording electroretinograms (ERGs) under constant darkness. The ERG amplitudes of both right and left compound eyes exhibited clear circadian rhythms due to direct efferent controls from the ipsilateral optic-lobe pacemakers. In the free-running state, the circadian period of the two pacemakers in each beetle ran parallel to each other. The phase-angle difference between the two pacemakers was generally close to 0° but we found that the two-oscillator system also stabilizes with phase-angles of 90°, 180° and 270°. Unilateral severance of the optic tract resulted in increased free-running period lengths of both the ipsilateral and contralateral pacemakers, indicating that the mutual neural interactions shorten the period.

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