NF005 - embryo sb - Stage 26 - 2006.08.16
Objective: Inject VII and VIII on the same side to see how much of the branchiomotor neuron labelling when injecting VIII might be leakage into facial as Bob Baker once suggested.
Procedure Bilateral injection:
- VIII: DiO crystals on caudal half of cochleovestibular ganglion
- VII: DiI crystals on distal branch of facial ganglion
Notes Dye application looks really good and clean, no signs of cross contamination. Good differentiation between facial and cochlear.
- RED NF005_Series005_ch00 z00-13 Low mag
- GREEN NF005_Series009_Ch00 z00-13 Low mag
- RGB NF005_Merging_00 Ch00 Ch01 z00-13 Low mag
- movie ImageJ nf005 merging 00.avi
- RED nf005_Series018_ch00 z00-40 higher mag
- GREEN nf005_Series019_ch00 z00-40 higher mag
- RGB from ImageJ nf005 merge 18_19 higher mag
- movie ImageJ nf005 merging 01.avi
Good differentiation between green and red. The points of entry of each of the nerves is well defined, with facial entering at a more ventromedial position.
Both rostral and caudal afferent bundles seem to be loosely fasciculated, but do not appear to form separate discrete bundles. There are clear varicosities and "filopodia-like" structures along the axons, but don't see clear collaterals. The rostral bundle seems to be travelling in between the two rostral caudal VIII bundles, and some close apposition between the two types of axons can be seen.
Efferent neurons form a dispersed column. Their axons in r5 course laterally reaching or almost reaching the sensory bundle where they make a sharp turn towards the nerve exit point. Axons from efferents in r4 seem to have their axons coursing directly to the nerve exit point.
Nerve entry well differentiated from VIII nerve, entering ventromedially to the entry of caudal VIII. There are numerous processes crossing the floor plate.
Posterior cochlear ganglion labeling
Both rostral and caudal sensory bundles seem to be split. The rostral bundle seems to be split into a longer thinner dorsolateral bundle and a seemingly less fasciculated medial bundle. The caudal bundle seems to be split into two and perhaps 3 bundles. Both bundles rostral and caudal show perpendicular projections of axons coursing towards the midline.
Efferent neurons are found in both r4-r5 and appear to occupy a more ventral position than the VII efferents. Labelling appears to be more intense in r4, where there seem to be two groups - a more dorsal one in a more lateral position and a more ventral one with cells all the way to the floor plate.
Nerve entry well differentiated from VII nerve, entering in a more dorsolateral position with respect to VII.
High magnification of the floor plate also shows extensions crossing the floor plate, as well as some fibres that seem to be coursing rostrocaudally at the edge of the floor plate.
There are also clearly labelled cell bodies in the dorsolateral edge of the wholemount, most likely in the alar plate. These lateral cell bodies can be found in r4 and r5 but they also seem to be present in r3.