PVN
The Mind of 
	a Worm

Members: PVNL, PVNR.

PVN is a set of two interneurons/motoneurons with cell bodies situated in the lumbar ganglia. Anteriorly directed processes enter the pre-anal ganglion via the lumbar commissures and then run alongside each other near the centre of the ventral cord. Prominent lateral branches enter the anterior regions of the vulva (e), running underneath the vm1 vulval muscles. These branches become quite large and contain a few vesicles, although no obvious focal synaptic contacts have been seen. The processes of PVN also branch extensively in the anterior extremities of the ventral cord; PVN is the most highly branched class of neuron in the nervous system. Many of the branches probably develop quite late, as PVN neurons in the JSH series (an L4 larva) had few branches. The branches of PVN tend to stay in the same neighbourhood as the main processes, running alongside them (they have been drawn separated for clarity). The main processes of both PVNL and PVNR enter the nerve ring on the right-hand side and run round it near the inside surface of the neuropile, in close association with the processes of BDU. PVNL has an additional branch, which enters the ring on the left- hand side, travelling in the same neighbourhood as the other branches of PVN. The synapses that are made by PVN are all rather small, with few vesicles in their synaptic terminals. In the nerve ring there are a few synapses to and from BDU (a, *c) and to AVJ (b). In the ventral cord the synapses are more numerous and are mainly onto AVD, NMJs (d), VDn, DDn (d), AVJ and PVW. There is a single gap junction to both HSN and PVQ, and a couple to AVB. Magnifications: (a, b) x 25500, (c, d) x 17000, (e) x 12750.


PVN ventral cord synapses
partners gap junctions synapses from synapses to and corecipients
AVD - - 2AVD, PQR, AVJ, AVA, AVE
PQR - - AVD, AVB, PVW
NMJ - - 3, VD12, 2DD1, VD3
PVW - - PQR, PVN, HDC
AVB 2 1m 1, PQR, HDC
PVN - 4m AVL, PVW, AVG, VD4
PVT - - 1,AVL
AVA - - 2, PVC, AVD, VD4, VA6
AVL - - 2PVN, PVT, VA6
HDC - - PVW, AVB
AVJ - - 2, AVD, AVJ, HSN, BDU
PVC - - 1,AVA
VD12 - - NMJ
AVG - 1+1m PVN
BDU - - AVJ
AVE - - 2,AVD
AVF - 1m RIF
RIF - - AVF
AVH - 1m -
PVQ 1 - -
DD1 - - 2NMJ
VD3 - - NMJ, DD2
DD2 - - VD3
VD4 - - 2, AVA, PVN
VC2 - - 1,VC3
VC3 - 1m VC2
VA6 - - AVL, AVA
DVB - - VD7
VD7 - - DVB
HSN - - AVJ
DB3 - - 1
DD3 - - 1
LUA - 1m -
VA11 - 2m -
VD12 - - NMJ
PDA - 1m -


Web adaptation, Thomas Boulin, for Wormatlas, 2001, 2002