Kubke Lab:/Notebook/Cranial nerve development/2014/12/16

Cranial Nerve Development

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Entry title General Helen I have been going over literature all day and will summarise my findings here: Article name and author Main point Implications for my research References to check out Diverse mechanisms for assembly of BMN, Cox et al 2011 In zebrafish, V = afferents enter first this is not true for VII, IX, X where efferents are proposed to enter and make way for afferents To check out whether this is true for chickens but my gut says that it is a similar difference because I see trigeminal afferents before I see facial afferents Honig 1998, Gilmour 2004 (axon towing), Begbie and Graham 2001 Developmental relationships between trigeminal ganglia and trigeminal MN I, Moody and Heaton 1983 Migration and early differentiation of MN not affected by removal of peripheral afferent innervation, Looks at the idea of distance to target being a reason for the differences in axon growth of cranial motorneurons and spinal motorneurons (where their targets are far closer in spinal motorneurons) Not the most relevant because it's talking about migration and differentiation post leaving the hindbrain, but the rationale about distance I find interesting Windle and Austen '36, Noden '75, Yntema '44, '43, Hollyday et al '77 Developmental relationships between trigeminal ganglia and trigeminal MN II Penetration of V afferents necessary for V efferents to exit (not just the presence of their cell bodies) Suggests that the physical penetration of afferents into the hindbrain plays a role for V efferents so provides a rationale for why that might be happening for other cranial nerves eg VII and VIII Windle '33, M Jacobsen '78 with a good quote on afferent bifurcation and guidance Developmental relationships between trigeminal ganglia and trigeminal MN III V motor axons grow preferentially towards V Parikarya after exiting the brainstem backs up idea demonstrated in II of the series - Neurogenin 1 null mutatns ...... Qiufu, David, 2000 Afferent innervation of inner ear is required for efferent outgrowth and in their absence some efferents project via facial nerve interesting to address gene knockout mice and think about their role within this, found it quite complex though and will need to read it again, one thing that I got from it that was potentially relevant was their use of soaked filter tips to dye nerve stubs which could be a potential new method? - Pathfinding by cranial nerve VII, CHang, Fan. Nayak 1992 Suggests stage 13 is the age for VII efferent devo (like V). Showed R4 ablation lead to variable patterns of growth in R5 rhombomeres but they always exited through a rhombomere with an even number (ie never through r5) also talks about lateral boundary line as a consistent place that efferents turn rostrally when in rhombomeres that don't have exit points, suggests a permissive field as mechanism for axon lateral movements and then the boundary of that is the point at which they turn rostrally (position denotes turning not direction though) dismisses role of afferent guidance as "this is probably not the case, as we have seen no evidence that sensory axons enter the hindbrain before the motorneurons exit" but would happily dispute or try test this, also the method here was immuno staining of mounted hind brains and could that be a potential way of imaging really delicate stage 13 or younger hind brains without having to dissect individual nerves? Jacobsen CO, '79 Fabiana