RIF is a set of two interneurons with cell bodies situated in the retro-vesicular ganglion.
Processes run anteriorly from the cell bodies and run in the interior of the ventral nerve cord
symmetrically disposed about the mid-line. They move to the dorsal surface of the cord as the
ring is approached and then run round either side of the ring on the inside surface near the
posterior face. The processes of RIF meet and terminate on the dorsal mid-line but do not have
a gap junction. The main synaptic output is to AVB in dyadic combination with RIM (a), AVJ (b), PVP (c) or ALM (d). The main synaptic input is from AIA (*a) via large synapses
in the neuropile of the ventral ganglion. There is also some synaptic input from HSN (*g).
A short process from AVG (*b) often pokes into the cell body of one of the RIFs. AVG has
gap junctions with both RIFs.
Magnifications: (a, d) x 25500, (b, c) x 17000.