Human-Evolution-Past-present-and-future.pdf
https://chakazul.github.io › Human-Evolution-Pas...
PDF
Chairman: Sir David Attenborough. Moderator: Marc Verhaegen.
:-)
Nature's Great Experiment:
the Evolution & Development of the Human Larynx.

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On Friday, November 18, 2022 at 4:27:16 PM UTC-5, littor...@gmail.com wrote:

Human-Evolution-Past-present-and-future.pdf
https://chakazul.github.io › Human-Evolution-Pas...
PDF
Chairman: Sir David Attenborough. Moderator: Marc Verhaegen.
:-)
Nature's Great Experiment:
the Evolution & Development of the Human Larynx.

See Gareth Morgan's very different solution to the puzzle of human larynx.

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Op vrijdag 18 november 2022 om 23:40:33 UTC+1 schreef DD'eDeN aka note/nickname/alas_my_loves:

Human-Evolution-Past-present-and-future.pdf
https://chakazul.github.io › Human-Evolution-Pas... PDF
Chairman: Sir David Attenborough. Moderator: Marc Verhaegen.
:-) Nature's Great Experiment: the Evolution & Development of the Human Larynx.

See Gareth Morgan's very different solution to the puzzle of human larynx.

Ah??

"Seafood, Diving, Song and Speech"
M.Verhaegen, M.Vaneechoutte & S.Munro 1999 already

... comparative data suggest that the various elements of human speech evolved at different times, and originally had different functions.
Recent work by Nishimura [1-6]: what is commonly known as the laryngeal descent actually evolved in a mosaic way, in minimally 2 steps:
(a) a descent of the thyroid cartilage (Adam’s apple) vs the hyoid (tongue bone), a descent also seen in non-human hominoids,
(b) a descent of the hyoid bone vs the palate, less obvious in non-human hominoids, and accentuated by the absence of prognathism in the short & flat human face.

Comparisons with other animals suggest
(a) the 1st descent might be ass.x loud sound production,
(b) the 2nd might be part of an adaptation to eating sea-foods: humans can suck shellfish into the mouth, and swallow it without chewing, even underwater.
We argue: the origin of human speech is based on different pre-adaptations that were present in human ancestors, e.g.
(a) sound production adaptations related to the descent of the thyroid cartilage ass.x the territorial calls of apes,
(b) transformation of the oral & dentitional anatomy, incl. the descent of the hyoid, ass.x reduced biting & chewing,
(c) diving adaptations, leading to voluntary control of the airway entrances & voluntary breath control.

After c 5 Ma,
- chimp ancestors became frugivores in tropical forests,
- human ancestors became littoral omnivores:
this helps explain why
- chimps did not evolve language skills,
- human language is a rel.recent phenomenon,
- it is so strongly dependent upon our voluntary breath control, not seen in other hominoids, but present in diving mammals.

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Human larynx motor cortices coordinate respiration for vocal-motor control Michel Belyl cs 2021 NeuroImage 239,118326
doi org/10.1016/j.neuroimage.2021.118326 free access

Vocal flexibility is a Hs hallmark, esp. the capacity to speak & sing.
It is supported in part by the evolution of a direct neural path-way, linking the motor cortex to the brain-stem nucleus that controls the larynx (the primary sound source for communication).
1) dLMC: Early brain imaging studies demonstrated:
larynx motor cortex at the dorsal end of the oro-facial division of motor cortex (dLMC) integrated laryngeal & respiratory control (coordinating 2 major muscular systems necessary for vocalization).
2) vLMC: Neuro-surgical studies have since demonstrated a 2nd larynx motor area at the ventral extent of the oro-facial motor division (vLMC) of motor cortex,
the vLMC has been presumed to be less relevant to speech motor control, but its functional role remains unknown.

We employed a novel ultra-high field (7T) MRI paradigm,
it combined singing & whistling simple melodies, to localise the larynx motor cortices, and test their involvement in respiratory motor control.
Whistling activated both ‘larynx areas’ more strongly than singing, despite the reduced involvement of the larynx during whistling!
We provide
- further evidence for the existence of 2 larynx motor areas in the Hs brain, - the first evidence that laryngeal-respiratory integration is a shared property of both larynx motor areas.
We outline explicit predictions about the descending motor pathways, that give these cortical areas access to both the laryngeal & respiratory systems,
we discuss the implications for the evolution of speech.

..... (e.g. beautiful illustrations)

Strong VPL abilities (vocal production learning) are uncommon in mammals.
The list of VLP is skewed towards spp whose evol.path has placed particular constraints on respiratory motor control.
1) VPL is most abundantly observed among aquatic mammals: Cetacea & Pinnipedia, they must coordinate breathing with bouts of diving, to manage the supply of O2, buoyancy & ambient ocean pressure.
2) Some elephant spp have demonstrated vocal production learning, which may be related to
-the unique demands of respiratory snorkelling,
-the possibly aquatic ancestry of these spp.
3) Bats exhibit a range of socially communicative vocalizations + echolocation,
they integrate respiratory control with echo-location calls (used for navigation),
but the muscles of respiration may interact directly with the muscular control of winged flight.
4) In this company, Hs appear to be the odd-mammal out, in lacking a clear selective pressure for enhanced respiratory motor control beyond its use in communication (Verhaegen cs 2002, see below).

.....

Conclusion:
The dLMC & vLMC are 2 larynx motor areas in the Hs brain, important cortical structures for the voluntary control of the voice,
both areas are also active during whistling, despite the reduced laryngeal involvement in that mode of sound production.
We suggest:
neither the dLMC nor the vLMC are strictly laryngeal:
both may integrate laryngeal & respiratory motor control.
Some clue to the separate functions of these brain regions may be found in the complex cyto-architecture of the vLMC (intermediate to primary motor & primary somato-sensory cortex).
Regardless, coordination with respiratory motor control appears to be a ubiquitous partner to laryngeal motor control:
the larynx sits in the airway, and any action of the larynx is likely to affect respiratory effort.
This has implications for our understanding of Hs brain evolution:
it alters our understanding of a well-documented specialisation for speech.

_____

ref.
M.Verhaegen, P.F.Puech & S.Munro 2002 "Aquarboreal ancestors?" Trends Ecol.Evol.17:212-7, 10.1016/S0169-5347(02)02490-4
:-) but why they didn't mention our other (12) publications on speech origins? e.g.
- MV & S.Munro 2004 Hum.Evol.19:53-70 "Possible preadaptations to speech – a preliminary comparative approach"
- M.Vaneechoutte, S.Munro & MV 2011 "Seafood, diving, song and speech" pp.181-9 in
M.Vaneechoutte cs eds 2011 "Was Man More Aquatic in the Past? Fifty Years after Alister Hardy: Waterside Hypotheses of Human Evolution" Bentham Sci.Publ.

--- SoupGate-Win32 v1.05
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On Wednesday, November 30, 2022 at 6:43:01 PM UTC-5, littor...@gmail.com wrote:

Human larynx motor cortices coordinate respiration for vocal-motor control Michel Belyl cs 2021 NeuroImage 239,118326
doi org/10.1016/j.neuroimage.2021.118326 free access

Vocal flexibility is a Hs hallmark, esp. the capacity to speak & sing.
It is supported in part by the evolution of a direct neural path-way, linking the motor cortex to the brain-stem nucleus that controls the larynx (the primary sound source for communication).
1) dLMC: Early brain imaging studies demonstrated:
larynx motor cortex at the dorsal end of the oro-facial division of motor cortex (dLMC) integrated laryngeal & respiratory control (coordinating 2 major muscular systems necessary for vocalization).
2) vLMC: Neuro-surgical studies have since demonstrated a 2nd larynx motor area at the ventral extent of the oro-facial motor division (vLMC) of motor cortex,
the vLMC has been presumed to be less relevant to speech motor control, but its functional role remains unknown.

We employed a novel ultra-high field (7T) MRI paradigm,
it combined singing & whistling simple melodies, to localise the larynx motor cortices, and test their involvement in respiratory motor control.
Whistling activated both ‘larynx areas’ more strongly than singing, despite the reduced involvement of the larynx during whistling!
We provide
- further evidence for the existence of 2 larynx motor areas in the Hs brain,
- the first evidence that laryngeal-respiratory integration is a shared property of both larynx motor areas.
We outline explicit predictions about the descending motor pathways, that give these cortical areas access to both the laryngeal & respiratory systems,
we discuss the implications for the evolution of speech.

..... (e.g. beautiful illustrations)

Strong VPL abilities (vocal production learning) are uncommon in mammals. The list of VLP is skewed towards spp whose evol.path has placed particular constraints on respiratory motor control.
1) VPL is most abundantly observed among aquatic mammals: Cetacea & Pinnipedia,
they must coordinate breathing with bouts of diving, to manage the supply of O2, buoyancy & ambient ocean pressure.
2) Some elephant spp have demonstrated vocal production learning, which may be related to
-the unique demands of respiratory snorkelling,
-the possibly aquatic ancestry of these spp.
3) Bats exhibit a range of socially communicative vocalizations + echolocation,
they integrate respiratory control with echo-location calls (used for navigation),
but the muscles of respiration may interact directly with the muscular control of winged flight.
4) In this company, Hs appear to be the odd-mammal out, in lacking a clear selective pressure for enhanced respiratory motor control beyond its use in communication (Verhaegen cs 2002, see below).

.....

Conclusion:
The dLMC & vLMC are 2 larynx motor areas in the Hs brain, important cortical structures for the voluntary control of the voice,
both areas are also active during whistling, despite the reduced laryngeal involvement in that mode of sound production.
We suggest:
neither the dLMC nor the vLMC are strictly laryngeal:
both may integrate laryngeal & respiratory motor control.
Some clue to the separate functions of these brain regions may be found in the complex cyto-architecture of the vLMC (intermediate to primary motor & primary somato-sensory cortex).
Regardless, coordination with respiratory motor control appears to be a ubiquitous partner to laryngeal motor control:
the larynx sits in the airway, and any action of the larynx is likely to affect respiratory effort.
This has implications for our understanding of Hs brain evolution:
it alters our understanding of a well-documented specialisation for speech.

_____

ref.
M.Verhaegen, P.F.Puech & S.Munro 2002 "Aquarboreal ancestors?" Trends Ecol.Evol.17:212-7, 10.1016/S0169-5347(02)02490-4
:-) but why they didn't mention our other (12) publications on speech origins? e.g.
- MV & S.Munro 2004 Hum.Evol.19:53-70 "Possible preadaptations to speech – a preliminary comparative approach"
- M.Vaneechoutte, S.Munro & MV 2011 "Seafood, diving, song and speech" pp.181-9 in
M.Vaneechoutte cs eds 2011 "Was Man More Aquatic in the Past? Fifty Years after Alister Hardy: Waterside Hypotheses of Human Evolution" Bentham Sci.Publ.

Okidoki, gibbon ancestors were seals. Yup. That's why they have both fur and SC fat and sing a lot. Yup. That's why they have long achilles tendons & long legs, cuz they waded and swam and dove daily and maybe slept underwater like mermaids. Yah, sure,
you bet ya.

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DD'eDeN aka note/nickname/alas_my_loves wrote:

Okidoki, gibbon ancestors were seals.

And your parents were cousins!







-- --

https://jtem.tumblr.com/post/702405882286391296

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Op donderdag 1 december 2022 om 04:50:55 UTC+1 schreef JTEM is so reasonable:

DD'eDeN aka note/nickname/alas_my_loves wrote:

Okidoki, gibbon ancestors were seals.

And your parents were cousins!

Yes, that kudu runner is a waste of time: intelligent enough to run after antelopes...

--- SoupGate-Win32 v1.05
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On Thursday, December 1, 2022 at 7:45:33 AM UTC-5, littor...@gmail.com wrote:

Op donderdag 1 december 2022 om 04:50:55 UTC+1 schreef JTEM is so reasonable:

DD'eDeN aka note/nickname/alas_my_loves wrote:

Okidoki, gibbon ancestors were seals.

And your parents were cousins!

Yes, that kudu runner is a waste of time: intelligent enough to run after antelopes...

Stille! You talk too much, and listen too little.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)