nf023- chicken sb embryo - Stage 26 - 2006.09.16
Objective Separate facial from auditory
Procedure Inject DiI in Metoh into ear vesicle and crystals of DiO into the facial nerve stump
- RIGHT ear vesicle: DiI MetOH
- LEFT ear vesicle: DiI MetoH
- RIGHT VII DiO cristal (maybe more on anterior branch)
- LEFT VII DiO crystal into stump
- nf023_Series007 z00-14
- nf023_Series011 z00-14
- nf023_Series022 z00-17
- nf023_Series025 z00-17
- nf023_Series029 z00-17
- nf023_Series030 z00-17
- nf023_Series035 z00-16
- nf023_Series039 z00-17
- nf023_Series041 z00-17
- nf023_Series050 z00-29
- nf023_Series054 z00-13
- nf023_Series056 z00-13
Labelling is quite symmetrical
The caudal bundle appearst to run in a bit of a medial position with respect to the rostral one. The rostral bundle is clearly separated into a longer more lateral one and a shorter more medial one at low magnification. When a slice stack is taken in a narrower part of VIII there are 2 clearly distinct groups of afferents - forming two bundles that run parallel and next to each other. I can see this clearly on the right side but not so much on the left side
Not a huge number compared to facial, but a singificant amount of labeling. All in the superficial group no deep column. Processes also cross the floor plate.
Caudal bundle running in a more medial position than rostral bundle. Didnt get much labelling of rostral bundle on the right side (where the dye placement was localised more to the anterior branch. On both sides the caudal branch is somewhat desfasciulated with a larger with more tightly placked axons on a medial position and a few defasciculated ones more laterally. On the right side I see what appears to be some ectopic afferents, running along the area where the motoneuron= axons make their rostral turn. Axons do not seem to extend beyond the level of entry of IX
Both groups of motoneurons are labelled.
Low magnification of red/green shows that there is a clear separation of the auditory and facial afferent bundles, with the facial afferents running more medially than the auditory ones. In contrast, axons of motoneurons seem to be running in close contact to each other, and at least at this stage, they do not appear to be segregated in the hindbrain. Facial BMN do not seem to cross the midline, but it appears that chochlear do (series 050 and free proj max 09) . The red axons also seem to be quite mixed in the more rostral set of MNs of VII and not in the deep group.
Questions I seem to be getting less efferents than when I inject VIII directly - but afferent labelling seems comparable. What does this say?