Physiology and morphology of descending neurons in pheromone-processing olfactory pathways in the male moth Manduca sexta

Ryohei Kanzaki, Edmund A. Arbas, John G. Hildebrand

Research output: Contribution to journalArticle

67 Scopus citations

Abstract

1. We have characterized the responses and structure of olfactory descending neurons (DNs) that reside in the protocerebrum (PC) of the brain of male sphinx moths Manduca sexta and project toward thoracic ganglia. 2. Excitatory responses of DNs to pheromone blends were of two general types: (a) brief excitation (BE) that recovered to background in <1 s after the stimulus, and (b) long-lasting excitation (LLE) that outlasted the stimulus by ≥1 s and, in many cases, as long as 30 s. Individual pheromone components were ineffective in eliciting LLE. 3. Some neurons showing LLE also exhibited state-dependent responses to pheromonal stimuli. When such neurons were in a state of low background firing, stimulation with pheromone blend elicited LLE. When they were in a state of LLE, an identical stimulus reduced firing for 5-10 s after which firing gradually increased to the initial higher level. 4. Thirteen stained DNs were reconstructed from serial sections for detailed analysis of their morphology in the brain. DNs exhibiting LLE had neurites concentrated in the lateral accessory lobes (LALs) in the protocerebrum and adjacent neuropil. Most DNs exhibiting only BE to pheromonal stimuli and other DNs showing responses only to visual or mechanosensory stimuli did not have branches in the LALs.

Original languageEnglish (US)
Pages (from-to)1-14
Number of pages14
JournalJournal of Comparative Physiology A
Volume169
Issue number1
DOIs
StatePublished - Jul 1 1991

Keywords

  • Manduca sexta
  • Moth
  • Olfactory interneurons
  • Pheromone
  • Protocerebrum

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Animal Science and Zoology
  • Behavioral Neuroscience

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