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Int'l Worm Meeting

Shawn Lockery shawn at chinook.uoregon.edu
Wed May 26 10:46:39 EST 1999


         Discussion topic for the 11th International C. elegans meeting

            A C. elegans Neurome Project: Whether and How

                   12:30 - 2:00 pm,  Capitol View Room

                 Organizers: Miriam Goodman and Shawn Lockery

One of the original goals of the C. elegans research community was to
understand the function of the nervous system and its genetic
regulation. The last several years have seen the development of
several important new techniques in C. elegans neurobiology:

         (1) patch-clamp recordings from identified neurons
         (2) patch-clamp recordings and sharp-electrode recordings from muscles
         (3) optical recordings from neurons and muscles
         (4) automated behavioral recordings

Have these new techniques, in combination with well-established
methods such as genetics, anatomical reconstruction, and laser
ablation, brought us to the point where a virtually complete
functional description of the Ce nervous system--a C. elegans neurome
project--is an attainable goal?

We would like to invite all members of the C. elegans research
community to an informal discussion centered around this question.  We
list below specific issues that are of general or immediate concern in
our minds.  However, we welcome suggestions for other topics now
(shawn at chinook.uoregon.edu) or during the discussion itself.

                         Immediate issues

1. Physiological salines.  Different labs are using different (and
arbitrary) external and internal salines, a disturbing trend that will
make it difficult to make general conclusions about the electrical
properties of C. elegans neurons and muscles.  Thus, there is a clear
need for standardized salines based on ion concentrations measured in
situ.  Several technologies exist for measuring ion concentrations in
tiny cells (e.g. x-ray microanalysis and ion-selective electrodes).
How can we accomplish this task?

2. GFP strain construction.  Recording from neurons identified by GFP
will be essential.  Many of the GFP strains produced so far are
unusable in electrophysiological experiments because they are not
integrated, because they are too dim, or because they use
transformation markers such as rol-6 which make it impossible to glue
the animal correctly.  What can be done about this problem?  How
should such strains be maintained and distributed?

3. Neuronal identities.  For many of the GFP strains currently
available the neurons have been identified only tentatively.
Relatively few laboratories are able to make definitive
identifications.  What can be done to ensure definitive
identifications are made in as many strains as possible?

4. Synaptic transmission.  To compute the behavior of neural networks
and their genetic regulation, we must know the polarity and dynamics
of wild-type chemical synapses.  Simultaneous whole-cell recordings
>from pre- and postsynaptic neurons remains a daunting prospect in
C. elegans, but much can be learned from other methods including (1)
extracellular stimulation coupled with recording from the postsynaptic
cell (neuron or muscle), (2) optical methods such as FM 1-43 and/or
synpatolucin or pHluorin (ph-sensitive GFP), and (3) measurement of changes
in whole-cell capacitance of presynaptic neurons.  How can we
coordinate our efforts to address the study of synaptic transmission?

                         Long-term issues

1. Is a C. elegans neurome project in one form or another a desirable

2. What form should the project take?  For example, should we aim for
a physiological profile of each neuron?

3. What steps should be taken in the short and long term to achieve
this goal?  Centralized vs decentralized organization?  Explicit

4. Data storage and distribution.  Should neurome data be stored and
distributed through ACeDB, or a separate entity?

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