<p>I am a member of <a href="http://www.openworm.org" rel="nofollow noreferrer">OpenWorm.org</a>, an open-source project that aims to simulate a C. elegans cell-by-cell. I didn't know the answer to this myself off the top of my head, but I have access to a number of folks who have been working hard on C. elegans anatomy for the last couple of years so I went ahead and asked them this question <a href="https://groups.google.com/forum/?fromgroups=#!topic/openworm-discuss/-GmHGJIZ5fQ" rel="nofollow noreferrer">on our discuss mailing list</a>. Thanks to Chris Grove and Tim Busbice for providing the answer that I am reporting below:</p>

<p><em>Chris Grove</em>:</p>

<blockquote>
  <p>Finding the neuron with the largest span partly depends on your
  definition of "length" in this context. In terms of largest amount of
  total axon/dendrite length, this would most probably be the PVDL/PVDR
  sensory neurons. They produce a large number of branches of dendrites
  that act to perceive mechano and thermo-sensation. See the <a href="http://wormatlas.org/neurons/Individual%20Neurons/PVDframeset.html" rel="nofollow noreferrer">WormAtlas
  page here</a>.</p>
</blockquote>

<p><em>Tim Busbice</em>:</p>

<blockquote>
  <p>If by "length" one means, absolute longest extension from head to
  tail, that's a tougher call, as there are several that extend from the
  head to the tail. An example of these are the AVDL/AVDR command
  interneurons, that function as touch modulators for backward
  locomotion induced by head-touch, and also drive backward movement of
  the animal along with driver cell AVA neuron, AVE and A-type motor
  neurons.</p>
</blockquote>

<p>You can find a lot of info on C. elegans anatomy on <a href="http://wormatlas.org/index.html" rel="nofollow noreferrer">WormAtlas</a> and on an <a href="https://docs.google.com/spreadsheet/ccc?key=0Avt3mQaA-HaMdHZWLWJEMkdrSGtIX0FMUlh2LXhXWnc#gid=0" rel="nofollow noreferrer">OpenWorm data spreadsheet</a> in which we are consolidating detailed anatomy data from different sources.</p>

<p>Also I would advise checking out the <a href="http://browser.openworm.org/" rel="nofollow noreferrer">OpenWorm Browser</a> - a web-based 3D viewer that you can use to explore the C. elegans anatomy cell-by-cell (the 3D model was developed by Chris Grove, see <a href="http://caltech.wormbase.org/virtualworm/" rel="nofollow noreferrer">VirtualWorm</a> for details). For instance you can easily search for those "longest" neurons mentioned above! Screenshot of one of them selected (AVDL) below:</p>

<p><img src="https://i.sstatic.net/nD1IW.png" alt="AVDL neuron"></p>

<p>Hope this helped!</p>

CC BY-SA 3.0
2013-03-05T12:45:42.183Z
Awesome answer!  I meant length in Tim Busbice's sense, since these types of neurons cause havoc for my network analysis.
Douglas S. Stones
CC BY-SA 3.0
2013-03-06T01:18:29.640Z
Glad to hear it helped - keep in mind AVDL/R are among the longest in that sense, but there are many neurons that span from head to tail, such as CANL/R [ http://www.wormatlas.org/neurons/Individual%20Neurons/CANframeset.html ].
JohnIdol
CC BY-SA 3.0
2013-03-05T01:18:44.580Z
2013-03-05T01:24:19.783Z
2013-03-05T01:24:19.783Z
JohnIdol
<p>The model organism <a href="http://en.wikipedia.org/wiki/Caenorhabditis_elegans" rel="nofollow noreferrer">C. elegans</a> is about 1 mm in length.  This is quite small.  In fact, some C. elegans neurons span >25% of the length of its body (<a href="http://www.wormatlas.org/neuronalwiring.html" rel="nofollow noreferrer">ref.</a>).</p>

<p><img src="https://i.sstatic.net/NI527.jpg" alt="Source: Wikipedia"></p>

<p>This observation leads me to the following question: Which neuron in C. elegans has the largest span, and why is it this large?</p>

<neuroscience>
In C. elegans, which neuron has the largest span, and why is it this large?
Douglas S. Stones
# In C. elegans, which neuron has the largest span, and why is it this large?

(Asked by: username_0 on 2013-02-21)

The model organism [C. elegans](http://en.wikipedia.org/wiki/Caenorhabditis_elegans) is about 1 mm in length. This is quite small. In fact, some C. elegans neurons span >25% of the length of its body ([ref.](http://www.wormatlas.org/neuronalwiring.html)).

![Source: Wikipedia](https://i.sstatic.net/NI527.jpg)

This observation leads me to the following question: Which neuron in C. elegans has the largest span, and why is it this large?

**Tags:** neuroscience


---

## 1 answers

### Answer by username_1 on 2013-03-05. Score: 5 | Accepted answer

I am a member of [OpenWorm.org](http://www.openworm.org), an open-source project that aims to simulate a C. elegans cell-by-cell. I didn't know the answer to this myself off the top of my head, but I have access to a number of folks who have been working hard on C. elegans anatomy for the last couple of years so I went ahead and asked them this question [on our discuss mailing list](https://groups.google.com/forum/?fromgroups=#!topic/openworm-discuss/-GmHGJIZ5fQ). Thanks to Chris Grove and Tim Busbice for providing the answer that I am reporting below:

*Chris Grove*:

> Finding the neuron with the largest span partly depends on your
> definition of "length" in this context. In terms of largest amount of
> total axon/dendrite length, this would most probably be the PVDL/PVDR
> sensory neurons. They produce a large number of branches of dendrites
> that act to perceive mechano and thermo-sensation. See the [WormAtlas
> page here](http://wormatlas.org/neurons/Individual%20Neurons/PVDframeset.html).

*Tim Busbice*:

> If by "length" one means, absolute longest extension from head to
> tail, that's a tougher call, as there are several that extend from the
> head to the tail. An example of these are the AVDL/AVDR command
> interneurons, that function as touch modulators for backward
> locomotion induced by head-touch, and also drive backward movement of
> the animal along with driver cell AVA neuron, AVE and A-type motor
> neurons.

You can find a lot of info on C. elegans anatomy on [WormAtlas](http://wormatlas.org/index.html) and on an [OpenWorm data spreadsheet](https://docs.google.com/spreadsheet/ccc?key=0Avt3mQaA-HaMdHZWLWJEMkdrSGtIX0FMUlh2LXhXWnc#gid=0) in which we are consolidating detailed anatomy data from different sources.

Also I would advise checking out the [OpenWorm Browser](http://browser.openworm.org/) - a web-based 3D viewer that you can use to explore the C. elegans anatomy cell-by-cell (the 3D model was developed by Chris Grove, see [VirtualWorm](http://caltech.wormbase.org/virtualworm/) for details). For instance you can easily search for those "longest" neurons mentioned above! Screenshot of one of them selected (AVDL) below:

![AVDL neuron](https://i.sstatic.net/nD1IW.png)

Hope this helped!

> **Comments:**
> **username_0**: Awesome answer!  I meant length in Tim Busbice's sense, since these types of neurons cause havoc for my network analysis.  
> **username_1**: Glad to hear it helped - keep in mind AVDL/R are among the longest in that sense, but there are many neurons that span from head to tail, such as CANL/R [ http://www.wormatlas.org/neurons/Individual%20Neurons/CANframeset.html ].  

---

