Followers of the leech command-like neuron Tr2 discovered using a FRET-based voltage indicator

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Followers of the leech command-like neuron Tr2
discovered using a FRET-based voltage indicator

• Adam L. Taylor
• Garrison W. Cottrell
• David Kleinfeld
• William B. Kristan, Jr.

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Tr2 terminates swimming
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Tr2 swim-termination pathways
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Voltage-sensitive dye imaging

• Impale one Tr2
• Inject current pulses to elicit bursts of spikes
  at 1 Hz

• Image a midbody ganglion, look for cells with
  activity at 1 Hz

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Imaging reveals Tr2 targets
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Imaging reveals Tr2 targets
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Optical recordings are very sensitive

• High sensitivity due to FRET-based
  voltage-sensitive dyes

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Tr2 spikes elicit 1-1 EPSPs

• Connections are monosynaptic, chemical

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256 and 54 stop swimming
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Cell morphologies
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Conclusions

• Using FRET-based voltage-sensitive dyes, we found
  three novel Tr2 targets 256, 252, and 54
• Two of these cells, cells 256 and 54, terminate
  swimming when driven strongly
• This suggests that these cells play a role in
  Tr2-induced swim stops
• We havent connected Tr2 to the swim CPG yet, but
  weve moved the cloud back one layer
• Optical recording is a very efficient way of
  finding synaptic targets

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Acknowledgements

• Tim Cacciatore
• Tito Gonzalez
• Roger Tsien
• Aurora Biosciences Corporation (now Panvera Ltd.)
• La Jolla Interfaces in Science, Burroughs
  Wellcome Fund
• National Institutes of Health GM08107