Optical analysis of circuitry for respiratory rhythm in isolated brainstem of foetal mice

Kenneth J. Muller, Gavriil Tsechpenakis, Ryota Homma, John G. Nicholls, Lawrence B. Cohen, Jaime Eugenin

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Respiratory rhythms arise from neurons situated in the ventral medulla. We are investigating their spatial and functional relationships optically by measuring changes in intracellular calcium using the fluorescent, calcium-sensitive dye Oregon Green 488 BAPTA-1 AM while simultaneously recording the regular firing of motoneurons in the phrenic nerve in isolated brainstem/spinal cord preparations of E17 to E19 mice. Responses of identified cells are associated breath by breath with inspiratory and expiratory phases of respiration and depend on CO2 and pH levels. Optical methods including two-photon microscopy are being developed together with computational analyses. Analysis of the spatial pattern of neuronal activity associated with respiratory rhythm, including cross-correlation analysis, reveals a network distributed in the ventral medulla with intermingling of neurons that are active during separate phases of the rhythm. Our experiments, aimed at testing whether initiation of the respiratory rhythm depends on pacemaker neurons, on networks or a combination of both, suggest an important role for networks.

Original languageEnglish (US)
Pages (from-to)2485-2491
Number of pages7
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Issue number1529
StatePublished - Sep 12 2009


  • Brainstem
  • Breathing
  • Calcium imaging
  • Two-photon microscopy

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)


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