Imaging reveals synaptic targets of a swim-terminating neuron in the leech CNS.
In the leech, the command-like neuron called cell Tr2 is known to stop swimming, but the connections from cell Tr2 to the swim central pattern generator have not been identified. We used fluorescence resonance energy transfer voltage-sensitive dyes to identify three neurons that are synaptic targets of cell Tr2. We then used electrophysiological techniques to show that these connections are monosynaptic, chemical, and excitatory. Two of the novel targets, cell 256 and cell 54, terminate swimming when stimulated. These neurons are likely to mediate swim cessation caused by cell Tr2 activity, and thus play the role of intermediate control cells in the leech CNS.
Taylor
Adam L
AL
Department of Computer Science and Engineering, University of California, San Diego, La Jolla, California 92093, USA. altaylor@brandeis.edu
Cottrell
Garrison W
GW
Kleinfeld
David
D
Kristan
William B
WB
D000818:Animals; D001522:Behavior, Animal; D002490:Central Nervous System / Q000166:cytology* / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials; D031541:Fluorescence Resonance Energy Transfer; D005724:Ganglia / Q000166:cytology / Q000502:physiology; D007865:Leeches / Q000166:cytology / Q000502:physiology*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009415:Nerve Net; D009433:Neural Inhibition; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D013550:Swimming / Q000502:physiology*; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure