Identification of neural circuits by imaging coherent electrical activity with FRET-based dyes

Neuron. 1999 Jul;23(3):449-59. doi: 10.1016/s0896-6273(00)80799-0.


We show that neurons that underlie rhythmic patterns of electrical output may be identified by optical imaging and frequency-domain analysis. Our contrast agent is a two-component dye system in which changes in membrane potential modulate the relative emission between a pair of fluorophores. We demonstrate our methods with the circuit responsible for fictive swimming in the isolated leech nerve cord. The output of a motor neuron provides a reference signal for the phase-sensitive detection of changes in fluorescence from individual neurons in a ganglion. We identify known and possibly novel neurons that participate in the swim rhythm and determine their phases within a cycle. A variant of this approach is used to identify the postsynaptic followers of intracellularly stimulated neurons.

Publication types

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

MeSH terms

  • Animals
  • Cell Membrane / physiology
  • Electrophysiology / methods*
  • Fluorescent Dyes*
  • Ganglia, Invertebrate / cytology
  • Ganglia, Invertebrate / physiology
  • Interneurons / cytology
  • Interneurons / physiology
  • Leeches
  • Microscopy, Fluorescence / methods
  • Motor Neurons / cytology*
  • Motor Neurons / physiology*
  • Movement / physiology
  • Nervous System / cytology
  • Neural Pathways
  • Swimming / physiology


  • Fluorescent Dyes