Hi people,
I am studying bat brains through endocranial casts and I cannot identify which structure could be present in sort of a canal located dorsally to the cribriform plate. It is like olfactory nerves exit the olfactory bulbs through the punctuated cribriform plate, while another thing exit the olfactory bulbs more dorsally, going over the cribriform plate. It's really bizarre because it's like a plate of space starting at the antero-dorsal top of the olfactory bulbs, and depending on the taxa it can variate in thickness (sometimes thinner at the center of the bulbs, sometimes the reverse).
I tried to search in the literature but I didn't find anything satisfying. I eliminated the possibility that these structures may be vomeronasal nerves (they originate at the dorsal top of the accessory olfactory bulb, so rather in the middle of the main olfactory bulb ; see Fig. 6 of Article The connection of the vomeronasal organ with the accessory o...
for instance) or the terminal nerve (aka cranial nerve 0) that also runs more ventrally (see Fig. 7 ofArticle Terminal nerve in the mouse-eared bat (Myotis myotis): Ontog...
for instance).Could anyone help me ? Even if you don't work on bats especially, but on other mammalian groups, any idea would be helpful.
Thanks a lot,
Jacob
Hello Jacob; If you have any specimens available - pickled, not frozen - doing a couple of dissections under a stereomicroscope might allow you to trace the structures. Even if the dissections are less than perfect you would get some hints. I'd practice on something larger than a bat, a rat perhaps. Good luck, Jim Des Lauriers
Hello James, and thanks for your answer !
I am working on skulls only, so I cannot do some dissections. It would be, of course, the best way to answer to my question, but unfortunately I cannot do this for now.
I searched in the literature for some sections of the skull with the brain, but, most of times, stereotaxic atlases provide sections of the brain only.
I also asked a colleague working on the nasal cavity in mammals (turbinals morphology, cribriform plate, etc.). He deals with both CT-scanned skulls and dissections, and he dissected several small mammals (rodents and "insectivors", but no bats); however, he couldn't help me when I showed him this free space over the cribriform plate in bats, so it seems that this may be specific to them.
Jacob; Somewhere, in a zoology lab, a pet store freezer, a local zoo, there is a specimen. I don't know your circumstances, nor the laws where you live, but I bet that you can find some critter - not necessarily a bat - that you could work on. Where did you get your skulls? Maybe that source could help. Cheers, Jim Des Lauriers
Jim - I got skulls in collections, but skulls were prepared to remove soft tissues. I know where to find specimens that I could study, but my main issue is that I am not qualified to do this (for now); I'm in my final year of PhD, so even if compare a brain to an endocast is a very interesting topic, this is not my problematic for now (basically, I simply describe fossil endocasts). That's why I'm asking the RG community, if someone already knows or has at least an hypothesis, I could save some time (and verify all of this later). Cheers, Jacob
Hi Jacob,
This seems pretty specific. You might get some help by contacting the authors of these articles and asking them about an answer: Article Vomeronasal and Olfactory Structures in Bats Revealed by Dic...
Article Peramorphosis, an evolutionary developmental mechanism in ne...
Just an idea. Good luck!
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