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Question about Vomeronasal Organ (VNO)?

F. Frank LeFever flefever at ix.netcom.com
Tue Aug 3 22:19:35 EST 1999

In <7o7766$ou6$1 at nnrp1.deja.com> *Hemidactylus*
<hemidactylus at my-deja.com> writes: 
>In article <7o3432$8mk at dfw-ixnews19.ix.netcom.com>,
>  flefever at ix.netcom.com(F. Frank LeFever) wrote:
>> About time for me to pop off on the basis of dim memories of stuff
>> possibly not well understood (by me) when I read it, and possibly
>> revised by later work, anyway.
>> Anyway, for what it's worth, I came to the conclusion, after a book
>> C. Judson Herrick sent me (c. 30-40 yrs ago?) to the comparative
>> anatomy literature then available, that while one might consider the
>> rhinal cortex (indeed, the whole cerebral cortex, ultimately, but
>> rrhinal cortex immediately?) an outgrowth of the olfactory nerve
>> (hypertrophy of its central ganglion), the amygdala (or some parts
>> it) could in the same sense be considered an outgrowth of the
>> vomeronasal organ.
    (F. LeFever)

>The amygdala is a nucleus involved with (among other functions I'd
>social interactions and aggression, right? It's been a while since
>studied some of the neurochemistry and assumed localization of
function for
>the limbic system and the basal ganglia and sundry assorted regions.
>Sometimes I feel like I'm running in place.
>It would seem reasonable that smell or pheromone reception and social
>interaction would be linked, but I'd think that this is a murky issue
>humans. We're not quite ants.

I didn't base my conclusions on any speculations about pheromones.
This was strictly an argument from comparative anatomical data.
If it makes sense in terms of pheromones, OK.

F. LeFever

Hemi continues (with my original responses quoted):

>Looking through my stack of papers, I noticed I have two which are
>to the VNO and pheromones, if any lurkers are interested:
>Weller A. 1998. Communication through body odour. Nature (392): 128-7
>and views)
>Stern K and McClintock MK. 1998. Regulation of ovulation by human
>Nature (392): 177-9 (letters to nature)
>I'm not quite sure to make of these articles, because I've heard of
>controversy surrounding these ideas.
>> Conceivably, it might persist in phylogeny even after its ancestral
>> point of origin atrophied.
>We have several "vestiges". From reading your posts in the past, I've
>you have some background in immunology. The vermiform appendix is a
>yet has some minor immunological function as I recall. Why not assign
>minor (relatively non-essential?) duty to something that's literally
>hanging around for the ride?
>I noticed that some vertebrate species might have a cranial nerve O
>nerve), but I'm not sure whether humans ever exhibit this as a
"vestige" or
>throwback to the embryology of ancestors. I guess this qualifies as
>pursuit biology :-)
>> In the absence of a vomeronasal organ, are there alternative routes
>> incoming pheromone signals?  One thinks of analogous non-geniculate
>> even non-retinal routes for photoperiod synchronization and other
>> "non-visual" aspects of light influences on neuroendocrine activity
>> behavior. Indeed, we don't even have to invoke the idea of light
>> filtering through your thinning hair to the pineal gland: one recent
>> study suggests that light to the back of the leg (behind the knee)
>> be effective for something or other (was it SAD treatment?
>> circadian rhythm?  I forget.)
>It's been quite a while since I was familiar with the intricacies of
>various biological rhythms. I covered this in ecology, but it was in
>abnormal psych course where I wrote a paper on this stuff. Basically,
as I
>recall, it was photons incident on the retina which triggger some
>neurochemical cascades involving both the suprachiamsatic nucleus of
>hypothalamus and the pineal gland (heavy hand waving here :-)). It all
>centers on the level at which melatonin is being enzymatically
produced (via
>an indole pathway) in the pineal.
>Biological rhythms might have a stricter control on the
>processes of other species, and just like pheromones, I'd ask whether
this is
>as important in humans anyway.
>Of course SAD is an issue. I recall the use of light banks for 15
minutes in
>the morning as a means of ameliorating the symptoms of SAD. It's been
so long
>since I've read about the circadian rhythms that I'm sure all my info
>somewhat out of date.
>As far as your mention of the light spot on the head, I think some
>(either snakes or lizards) have a "third eye" which is apparent from a
>discoloration on top of the head. I'm not sure how widely this trait
>through the reptiles.
>> In <7nq0ut$rp5$1 at nnrp1.deja.com> *Hemidactylus*
>> <hemidactylus at my-deja.com> writes:
>> >
>> >In article <19990725205613.06206.00001365 at ng-fu1.aol.com>,
>> >  holson1000 at aol.com (Howard Olson) wrote:
>> >> >Does anyone know if reconstruction of the nasal pathways (a nose
>> job) would
>> >> >typically damage or destroy the Vomeronasal Organ (VNO)?
>> >> >
>> >> >Thanks.
>> >>
>> >>   It would obviously depend on the extent of the surgery. But the
>> real problem
>> >> is the fact that many medical experts did not believe in a human
>> until it
>> >> was proven
>> >> that humans did have pheromones like the axillary androgens. Hope
>> that
>> >> helps.....
>> >>
>> >>
>> >
>> >One question I've had, which come from something I picked up in a
>> comparative
>> >anatomy class, is whether humans have cranial nerve O (aka the
>> terminal
>> >nerve). I think, if memory serves me correctly, the terminal nerve
>> >developed in elasmobranchs but that there is controversy over
>> such a
>> >cranial nerve exists in mammals or humans especially. This might
>> in with
>> >the VNO / pheromone issue. I've had a literature search on
>> synchony
>> >on the backburner, so I should motivate myself to explore this
>> interesting
>> >issue (ie- pheromones and human physiology/behavior).
>> >
>> >The terminal nerve question really eats at me though, since I'm
>> interested in
>> >things that are conserved in evolution (ie- homologies). Do we
>> this
>> >cranial nerve O feature with our elasmobranchian fellow vertebrates
>> has
>> >our "lineage" (sic) abandoned this.
>> >
>> >--
>> >Scott Chase
>> >
>> >
>> >Sent via Deja.com http://www.deja.com/
>> >Share what you know. Learn what you don't.
>Scott Chase
>Sent via Deja.com http://www.deja.com/
>Share what you know. Learn what you don't.

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