Varshney et al. 2011

Structural Properties of the Caenorhabditis elegans Neuronal Network

Lav R. Varshney, Beth L. Chen, Eric Paniagua, David H. Hall, Dmitri B. Chklovskii
PLOS Computational Biology 7(2): e1001066
Published: February 3, 2011

Data Acquisition

Assembled wiring diagram by consolidating existing data from both published and unpublished sources

White et al- The Mind of a Worm (MOW) (starting point)

extracted wiring data from diagrams, figures, tables and text
connectivity of each neuron, its synaptic partner, and synaptic type was manually entered into an electronic database
in the ventral cord, determining this level of synaptic specification was complicated by the fact that connections were recorded by neuron class
assigned proper connections to the appropriate left/right neuronby referring to White and coworker's original laboratory notebooks and original EMs

R.M. Durbin- the anterior portion of the worm

Anterior connections needed an update as MOW did not specify the location of syanpses, integration proved difficult
For these neurons, they obtained positional information by cross-referencing Durbin's data against original EMs and his handwritten annotations in White's laboratory notebooks
Only synapses located in regions addressed by Durbin were included
Connections in the middle and tail region of the worm were mostly unaffected by these updates.

Differences in data and gaps

[Hobert O and Hall DH, unpublished] differences between GFP neurons and White's work have been observed
- anterior processes of DVB and PVT could have been mistakenly switched in MOW
- so they reversed the connections for neurons DVB and PVT anterior to the vulva
reconstructions of neurons in the mid-body of the wor are incomplete
from a combination of these published works
- White et al 1986
- Durbin RM 1987
- Hall DH, Russel RL 1991
- White et al 1976
wiring data for 64 neurons had large gaps or were missing entirely
- 61 of these were motor neurons in the ventral cord
2 were excretory neurons (CANL/R) that do not appear to make any synapses
- RID is the only process in the dorsal cord that extends over the length of the animal

Updates to previous data

Using a White et al laboratory notebooks, they identified notes for full reconstructions of 24 of the aforementioned neurons
Partial connectivity data for the remaining 38 were also available where 22 neurons have partial/missing dorsal side connections and 6 neurons have partial ventral side connections
600 updates were made to the original notes and published reconstructions -additions of previously missed NMJs between ventral cord motor neurons and body wall muscles -large section on the dorsal side of the worm was never EM at high power magnification
produced new high power EMs of this dorsal region
3 neurons (DA5,DB4,DD3) were obtained from these EMs
resource constraints prevented them from covering the entire dorsal gap
reconciliation of discrepancies -561 synapses for 108 neurons (49% chemical "sends", 31% chemical "receives" and 20% for electrical junctions)