Worm Breeder's Gazette 1(1): 17a

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Title unknown.

Authors unknown.

We have been studying the structure of the N2 hermaphrodite ventral 
and dorsal nerve cords for some time and have recently extended these 
studies to L1 larvae prior to the post-embryonic development that 
takes place.
The adult has 5 classes of motor neurone in the ventral cord 
designated A, B, C, AS and D.  Classes A, B and D can be divided into 
two sub-classes; those that innervate the ventral muscles and those 
that have axones that run in the dorsal cord and innervate the dorsal 
muscles.  Class AS only innervate dorsal muscles and class C only 
innervate the ventral muscles (predominantly the sex specific muscles).
Classes A, B, and AS are driven from interneurones that come from 
the nerve ring.  Class D neurones that innervate the ventral side have 
a dendritic process on the dorsal which is driven by all the other 
motor neurones active in its locality.  Conversely, dorsal type D 
receive their innervation from ventral motor neurones and innervate 
the dorsal body muscles.  If all the motor neurones which are known to 
develop post-embryonically are subtracted one is left with the 
complement of motor neurones which is present in the L1 larva and 
these turn out to be dorsal A, B, and D.  This seemed paradoxical, but 
when the nerve cords of an L1 were looked at it was seen that the 
cells which were dorsal type D's in the adult innervate the ventral 
side of the L1, receiving their innervation from a dendrite on the 
dorsal side which is driven by the dorsal type A and B motor neurones. 
Thus it seems as if these cells 're-wire' in the course of 
development.  We are now trying to find out whether this re-wiring is 
induced by the arrival of the new motor neurones or is autonomous.