A logical skill of some invertebrates

Source: https://news.umich.edu/paper-wasps-capable-of-behavior-that-resembles-logical-reasoning/Date May 7, 2019

ANN ARBOR—A new University of Michigan study provides the first evidence of transitive inference, the ability to use known relationships to infer unknown relationships, in a nonvertebrate animal: the lowly paper wasp.

For millennia, transitive inference was considered a hallmark of human deductive powers, a form of logical reasoning used to make inferences: If A is greater than B, and B is greater than C, then A is greater than C.

But in recent decades, vertebrate animals including monkeys, birds and fish have demonstrated the ability to use transitive inference.

The only published study that assessed TI in invertebrates found that honeybees weren’t up to the task. One possible explanation for that result is that the small nervous system of honeybees imposes cognitive constraints that prevent those insects from conducting transitive inference.

Paper wasps have a nervous system roughly the same size—about one million neurons—as honeybees, but they exhibit a type complex social behavior not seen in honeybee colonies. University of Michigan evolutionary biologist Elizabeth Tibbetts wondered if paper wasps’ social skills could enable them to succeed where honeybees had failed.

To find out, Tibbetts and her colleagues tested whether two common species of paper wasp, Polistes dominula and Polistes metricus, could solve a transitive inference problem. The team’s findings were published online May 8 in the journal Biology Letters.

This study adds to a growing body of evidence that the miniature nervous systems of insects do not limit sophisticated behaviors,” said Tibbetts, a professor in the Department of Ecology and Evolutionary Biology.

We’re not saying that wasps used logical deduction to solve this problem, but they seem to use known relationships to make inferences about unknown relationships,” Tibbetts said. “Our findings suggest that the capacity for complex behavior may be shaped by the social environment in which behaviors are beneficial, rather than being strictly limited by brain size.”

To test for TI, Tibbetts and her colleagues first collected paper wasp queens from several locations around Ann Arbor, Michigan.

In the laboratory, individual wasps were trained to discriminate between pairs of colors called premise pairs. One color in each pair was associated with a mild electric shock, and the other was not.

I was really surprised how quickly and accurately wasps learned the premise pairs,” said Tibbetts, who has studied the behavior of paper wasps for 20 years.

Later, the wasps were presented with paired colors that were unfamiliar to them, and they had to choose between the colors. The wasps were able to organize information into an implicit hierarchy and used transitive inference to choose between novel pairs, Tibbetts said.

I thought wasps might get confused, just like bees,” she said. “But they had no trouble figuring out that a particular color was safe in some situations and not safe in other situations.”

So, why do wasps and honeybees—which both possess brains smaller than a grain of rice—perform so differently on transitive inference tests? One possibility is that different types of cognitive abilities are favored in bees and wasps because they display different social behaviors.

A honeybee colony has a single queen and multiple equally ranked female workers. In contrast, paper wasp colonies have several reproductive females known as foundresses. The foundresses compete with their rivals and form linear dominance hierarchies.

A wasp’s rank in the hierarchy determines shares of reproduction, work and food. Transitive inference could allow wasps to rapidly make deductions about novel social relationships.

That same skill set may enable female paper wasps to spontaneously organize information during transitive inference tests, the researchers hypothesize.

For millennia, transitive inference was regarded as a hallmark of human cognition and was thought to be based on logical deduction. More recently, some researchers have questioned whether TI requires higher-order reasoning or can be solved with simpler rules.

The study by Tibbetts and her colleagues illustrates that paper wasps can build and manipulate an implicit hierarchy. But it makes no claims about the precise mechanisms that underlie this ability.

In previous studies, Tibbetts and her colleagues showed that paper wasps recognize individuals of their species by variations in their facial markings and that they behave more aggressively toward wasps with unfamiliar faces.

The researchers have also demonstrated that paper wasps have surprisingly long memories and base their behavior on what they remember of previous social interactions with other wasps.

The other authors of the new Biology Letters paper—Jorge Agudelo, Sohini Pandit and Jessica Riojas—are undergraduates...

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The sharing of food, experience and emotions


(Source: BBC Future Can the roots of spiritual behaviours and feelings be found in other animals? First part. By Brandon Ambrosino 19 April 2019 .)

(Excerpts)

The article is written from the viewpoint of a particular, namely Christian religious tradition. But it operates with general paleoanthropological evidence that pertains to the whole genesis of humankind.

Homo sapiens wasn’t the only species to discover the benefits of food-sharing. Neanderthals certainly pooled their resources, as did the several other Homo species dating back two million years.””But food-sharing even predates our Homo ancestors, and is currently observed in chimpanzees and bonobos. In fact, one recent paper even documented research of bonobos sharing food with bonobos outside of their own social group.”

While much of the scientific study of religion is on theology-based doctrinal religions, the evolutionary psychologist Robin Dunbar thinks this is a narrow way of studying the phenomenon because it “completely ignores the fact that for most of human history religions have had a very different shamanic-like form that lacks gods and moral codes”. (By shamanic, Dunbar means religions of experience that commonly involve trance and travel in spirit worlds.) While the theology-based forms are only a few thousand years old and characteristic of post-agricultural societies, Dunbar argues that the shamanic forms date back 500,000 years. These, he claims, are characteristic of hunter-gatherers.

…some theorists such as Dunbar argue that we should also look beyond the individual to the survival of the group.

This is known as multilevel selection, which “recognises that fitness benefits can sometimes accrue to individuals through group-level effects, rather than always being the direct product of the individual’s own actions”, as Dunbar defines it.

An example is cooperative hunting, which enables groups to catch bigger prey than any members could catch as individuals. Bigger prey means more for me, even if I have to share the meat (since the animal being shared is already larger than anything I could catch alone). Such group-level processes “require the individual to be sensitive to the needs of other members of the group”, says Dunbar.

The similarities between humans and chimps are well known, but one important difference has to do with group size. Chimpanzees, on average, can maintain a group size of about 45, says Dunbar. “This appears to be the largest group size that can be maintained through grooming alone,” he says. In contrast, the average human group is about 150, known as Dunbar’s Number. The reason for this, says Dunbar, is that humans have the capacity to reach three times as many social contacts as chimps for a given amount of social effort.

How did nature achieve the socialisation process? Jonathan Turner, author of The Emergence and Evolution of Religionsays the key isn’t with what we typically think of as intelligence, but rather with the emotions, which was accompanied by some important changes to our brain structure. Although the neocortex figures prominently in many theories of the evolution of religion, Turner says the more important alterations concerned the subcortical parts of the brain, which gave hominins the capacity to experience a broader range of emotions.

As selection worked on existing brain structures, enhancing emotional and interpersonal capacities, certain behavioural propensities of apes began to evolve. Some of the propensities already present in apes included: the ability to read eyes and faces and to imitate facial gestures; various capacities for empathy; the ability to become emotionally aroused in social settings; the capacity to perform rituals; a sense of reciprocity and justice; and the ability to see the self as an object in an environment.

As the ape line evolved from our last common ancestor in more open environments, it was necessary to pressure apes, who prefer to go it alone, to form more lasting social structures. Natural selection was able to accomplish this astonishing feat by enhancing the emotional palettes available that had long been available to our ancestors…

Self awareness and neural processes

S

Self reflection corellates wirh anterior medial prefrontal and posterior cingulate activation

(Excerpts)

SOURCE:

Neural correlates of self‐reflection

Sterling C. Johnson Leslie C. Baxter Lana S. Wilder James G. Pipe Joseph E. Heiserman George P. Prigatano

Brain, Volume 125, Issue 8, August 2002, Pages 1808–1814, https://doi.org/10.1093/brain/awf181

Published:

01 August 2002

The capacity to reflect on one’s sense of self is an important component of self‐awareness. In this paper, we investigate some of the neurocognitive processes underlying reflection on the self using functional MRI. Eleven healthy volunteers were scanned with echoplanar imaging using the blood oxygen level‐dependent contrast method. The task consisted of aurally delivered statements requiring a yes–no decision. In the experimental condition, participants responded to a variety of statements requiring knowledge of and reflection on their own abilities, traits and attitudes (e.g. ‘I forget important things’, ‘I’m a good friend’, ‘I have a quick temper’). In the control condition, participants responded to statements requiring a basic level of semantic knowledge (e.g. ‘Ten seconds is more than a minute’, ‘You need water to live’). The latter condition was intended to control for auditory comprehension, attentional demands, decision‐making, the motoric response, and any common retrieval processes. Individual analyses revealed consistent anterior medial prefrontal and posterior cingulate activation for all participants. The overall activity for the group, using a random‐effects model, occurred in anterior medial prefrontal cortex (t = 13.0, corrected P = 0.05; x, y, z, 0, 54, 8, respectively) and the posterior cingulate (t = 14.7, P = 0.02; x, y, z, –2, –62, 32, respectively; 967 voxel extent). These data are consistent with lesion studies of impaired awareness, and suggest that the medial prefrontal and posterior cingulate cortex are part of a neural system subserving self‐reflective thought…

The capacity to consciously reflect on one’s sense of self is an important aspect of self‐awareness. A sense of self is a collection of schemata regarding one’s abilities, traits and attitudes that guides our behaviours, choices and social interactions. The accuracy of one’s sense of self will impact ability to function effectively in the world. A patient for whom self‐awareness is compromised may have a sense of self regarding abilities and traits that is not congruent with what others observe (Stuss, 1991; Prigatano, 1999). For example, a brain‐injured patient may feel he/she can competently return to the same level of employment when observations by others indicate otherwise. When asked, brain‐injured patients often underestimate their own emotional dyscontrol, cognitive difficulties and interpersonal deficits relative to a family member’s rating of their abilities (Prigatano, 1996). Inaccurate self‐knowledge can significantly impede efforts to rehabilitate brain‐injured patients, since they may not appreciate the need for such treatment (Sherer et al., 1998a, b).

Hughlings Jackson postulated that a sense of self is dependent on the evolutionary development of the prefrontal cortex …

Consistent and robust anterior medial prefrontal and posterior cingulate activation during self‐reflection was observed in all 11 participants. While the peak of the activation varied somewhat between individuals, the preponderance of activity was always within AMPFC, BA 9 and 10, and posterior cingulate, in the area of BA 23, 30 and 31. Activation of the anterior medial prefrontal region was consistent with our hypothesis and with lesion studies of patients with impaired self‐awareness (Stuss, 1991). The consistency and magnitude of the activation was, however, somewhat greater than expected. “

Beszéd és zene

2019. április 17., szerda 15:29 |

…nem ugyanaz meghallgatni a kedvenc albumunkat, mint egy előadást vagy politikai beszédet. Látszólag teljesen más történik – ki gondolná, hogy mindeközben az agyunkban nagyon is hasonló folyamatok játszódnak le?

A verbális és a zenei kommunikáció

A zene és a beszéd között sok párhuzamot fedezhetünk fel. Talán nem is kell sokat taglalni, hogy mindkettő alapvetően kommunikációs funkciókkal rendelkezik, érzéseket, gondolatokat közvetítünk velük. Ha egy kicsit tovább megyünk, azt is megfigyelhetjük, hogy egymást követő hangokból állnak, amelyek egy hierarchikus szabályrendszer szerint rendeződnek egységekké – a hangok először szavakká és zenei motívumokká, majd ezek mondatokká és zenei paragrafusokká állnak össze és alkotnak egyre nagyobb részeket.

Emellett pedig a hangok magassága, jellege és ritmikája mindkét tevékenységben szerepet játszik a jelentés meghatározásában. Így már talán nem is meglepő, hogy a beszéd és a zene agyi feldolgozása részben közös agyterületeken történik – például az elsősorban beszédközpontként számon tartott Broca-mező, és a Wernicke-mező területén –, elvégre mindkettő akusztikus ingerek feldolgozását és létrehozását is jelenti. Több kutatásban is kimutatták, hogy a zenében szerzett kifinomult képességek pozitívan befolyásolják a beszédértés egyes összetevőit, mint a hangmagasság vagy a hangsúlyok érzékelése.

Szintén közös a beszédben és a zenében, hogy mindkettőnél hosszas gyakorlás során elsajátított készségeket, hangokat és mozdulatokat használunk – anélkül, hogy ez különösebben sok kognitív erőfeszítést jelentene a számunkra. A hangszeres tudás elsajátítása ilyenformán hasonlítható ahhoz, mint amikor megtanulunk vezetni: az első néhány alkalomkor tudatosan figyelünk a kuplung-váltó-kuplung mozdulatsor helyes elvégzésére, de pár óra gyakorlás után már automatikusan végezzük. A zene esetén sem gondolkodunk azon, hogyan üssünk le egy-egy billentyűt a zongorán – és a beszéd során sem törjük azon a fejünket, hogy milyen sorrendben kövessék egymást a szavak a nyelvtani helyesség érdekében.  De hogyan válik mindez kommunikációvá?

Rapperek és dzsessz-zongoristák az fMRI-ben

Megkerülhetetlen tehát a kettő közötti hasonlóság, hiszen ugyanazok az akusztikus paraméterek (például hangmagasság, hangintenzitás) határozzák meg a kettő jelentéstartalmát. A beszéd és a zene is a mondanivalónk/szándékaink közvetítését jelenti akusztikus ingerek segítségével. Így az improvizációs zenét, pontosabban a két vagy több zenész között zajló interaktív zenei improvizációt felfoghatjuk egy kommunikációs modellként is.

A beszéd és az improvizáció együttesét leginkább a freestyle, vagyis az improvizált rapben érhetjük tetten. Erre alapozva végzett agykutatást a Siyuan Liu által vezetett kutatócsoport 2012-ben, amikor rapperek agyi aktivitását mérték improvizáció alatt. A kapott eredmények közül kettőt is érdemes kiemelni. Az első, hogy a tevékenység alatt – érthető módon – aktívak voltak az agy beszéddel foglalkozó, beszédet feldolgozó területei, azonban ez az aktivitás nagyobb volt annál, mint ami általánosságban mérhető a hétköznapi beszéd során. A másik jelentős eredmény, mely az improvizáció jelenségéhez köthető, hogy az agynak egy olyan területében, ami többek közt önmagunk és viselkedésünk megfigyeléséért felel, a kutatók jelentős deaktivációt tapasztaltak – miközben megnövekedett aktivitás volt mérhető egy olyan agyterületen, amelynek egyik szerepköre – többek közt – az önkifejezés és az asszociációk tanulása.

Hogyan mérik a kutatók az agyi aktivitást?

Az emberi agy idegsejtek, vagy más néven neuronok hálójából áll, amelyek között az információ elektromos impulzusok formájában közvetítődik. Ezeket az impulzusokat különböző képalkotó technikákkal mérhetik – a tárgyalt kísérletekben egy fMRI, vagyis functional magnetic resonance imaging nevű technikát használtak. Az agynak azokon a területein, ahol több elektromos impulzus jelenik meg, a véroxigén-szint is megnő. Az oxigénnel telített hemoglobin-molekulák mágneses tulajdonságai eltérnek a telítetlen hemoglobin-molekulákétól. Az fMRI vizsgálat során ezt a különbséget mérik, és ebből következtetnek az agyi aktivitásra.

Hasonló eredményeket kaptak egy másik kutatásban, ahol improvizáló zongoristák agyi tevékenységét figyelték meg. A következtetések szerint az önmegfigyelést végző agyterület „kikapcsolása” szükséges az improvizáció megvalósulásához, miközben az önkifejezéssel foglalkozó agyterület nagyobb mértékben aktiválódik – Siyuan Liu kutatásában, amelyben a rappereket vizsgálták, ezt a jelenséget a flow-élménnyel hozzák kapcsolatba.  

A flow-, vagy más néven áramlat-élmény röviden az az élmény, amikor nagy átéléssel végzünk egy olyan tevékenységet, ami magas fokú koncentrációt igényel, azonban ezt abban a pillanatban nem erőfeszítésnek, hanem élvezetnek éljük meg. A „tökéletes élmény” pszichológiájával Csíkszentmihályi Mihály foglalkozott először.

Mi a különbség az improvizáció, és a nem-improvizáció között?

Általános esetben a cselekvési impulzusok kiindulópontja a homloklebeny egyes részei, melyek közé az előbb említett, önkifejezéssel és asszociáció-tanulással összefüggésbe hozható agyterület is tartozik. Ezen a területen jönnek létre a cselekvési impulzusaink, majd utána áthaladnak azon a területen is, amelyik az önmagunk és viselkedésünk megfigyeléséért is felelős  – ennek köszönhető, hogy eldönthetjük, végrehajtjuk-e az adott cselekvést, ami eszünkbe jutott. Illetve ennek a folyamatnak tulajdoníthatjuk az ágens-érzetünket is (vagyis, hogy úgy érzékeljük, szerzői, irányítói vagyunk a saját cselekedeteinknek). Az információ csak azután halad tovább a mozgatásért felelős területekre, miután ezen az agyterületen felülbíráltuk.

Siyuan Liu kutatásában azt a feltételezést fogalmazzák meg, hogy az improvizáció során a felülbírálást végző agyterület deaktivációja egyúttal a cselekvés megvalósulásának alternatív útját teszi lehetővé. Ennek hatására megszűnik az ágens-érzetünk, az improvizáció olyan élménnyé válik, mintha nem mi lennénk a saját cselekedeteink irányítói. Az információnak ezt az alternatív útvonalát hozzák kapcsolatba a flow-élménnyel.

A zenei improvizáció, mint kommunikációs eszköz

De vajon mi történik akkor, ha az improvizációs zenét kommunikációs kontextusban vizsgáljuk? A dzsessz-zongoristák agyi tevékenységét vizsgáló kísérlet alapján a kutatók végeztek egy olyan kísérletet is, mikor a szóló improvizáció helyett „négyeseket cserélgető” zongoristákat helyeztek az fMRI-be. A „négyesek cseréje” a dzsesszben szokásos tevékenység, mikor a zenészek felváltva játszanak egymásnak improvizált ütemeket. A szekvenciákkal egymás játékára is reagálnak, így a tevékenységük nemcsak improvizatív, hanem kommunikációs jellegű is lesz.

Az improvizáció során „négyeseket cserélgető” zongoristák esetében érdekes módon nem volt mérhető az a jelenség, amit a szóló improvizációnál tapasztaltak – nevezetesen, hogy az önmegfigyelést végző agyterület aktivációja csökken. Erre többféle magyarázat is felmerül, például az, hogy a kommunikációs helyzetekben szükséges az úgynevezett topic maintenance, figyelni kell a másik fél mondanivalójára – legyen az akár zenei, akár verbális. Ez amiatt releváns a zongoristák esetében, mert a válaszolgatós improvizáció során ugyanúgy „témánál maradnak”, mint egy beszélgetésben, az előző fél zenei motívumaira reagálva.

Ebben a tekintetben tehát más agyi folyamatok zajlanak a társas improvizáció alatt, mint a szóló improvizációnál. Az a jelenség, amelyet Siyuan Liu kutatásában a flow-élménnyel hoznak kapcsolatba, nem mérhető akkor, amikor a résztvevők egymásnak válaszolgatnak.

Az viszont fontos eredmény, hogy ugyanez a jelenség – a flow-élményhez kötött – megjelenik akkor, amikor a résztvevők nem hangszeren, hanem szavakkal improvizálnak. Tehát a flow-élmény megjelenése független attól, hogy zenei elemeket, vagy pedig verbális elemeket használunk az improvizáció során.

Ez az eredmény kifejezetten érdekes, ha azzal vetjük össze, hogy más agyterületek is átfedésben vannak e két tevékenység, a beszéd és a zene megvalósulásakor; például a sokáig nyelv-specifikusnak tartott Broca- és Wernicke-mező.

Véleményem szerint ezek a hasonlóságok, a közös neurológiai háttér sok kérdést vet fel, például a beszéd és a zene kialakulásának eredetét. Mivel a beszéd és a zene kommunikációs funkcióit tekintve, és az agyi feldolgozás szempontjából is ennyire hasonló, talán az is elképzelhető, hogy ugyanabból a vokális kommunikációból alakultak ki, és csak később váltak külön műfajokká. Részben hasonló következtetésre jut Merlin Donald evolúciós-antropológiai elgondolásaiban a kommunikáció kialakulásáról. Mivel ugyanazokat a funkciókat használjuk ebben a két tevékenységben, akár az is elképzelhető, hogy eredetileg egy tevékenységből alakultak ki, és a további fejlődésük során lettek ennyire különbözőek – például abban a tekintetben, hogy a beszéd sokkal alkalmasabb elméleti gondolatok közvetítésére, mint a zene, ami pedig sokszor az érzelmi tartalmak átadásában hatásosabb.

Így bár első ránézésre más meghallgatni a kedvenc számunkat, mint például egy izgalmas egyetemi előadást, az ezek mögött álló agyi folyamatok, és bizonyos gondolati mechanizmusok jobban hasonlítanak egymásra, mintsem azt elsőre gondolnánk.  

Kutya személyisége

A kutyafajtáknak nincs személyiségük

Varga-Molnár Orsolya

követés

2019. február 10., vasárnap 14:3

Attól, hogy egy kutyafajtára bizonyos tulajdonságok jellemzőek, még nem jelenti azt, hogy mindegyikük garantáltan olyan lesz. Személyiségük ugyanis az egyes egyedeknek van, nem pedig a fajtáknak.

Több száz kutyafajta van a világon, melyeket eredetileg valamilyen feladatra tenyésztettek ki. A többségnél az volt az elsődleges, hogy képes legyen megfelelően ellátni a funkcióját, ám sok fajtánál a külső megjelenés is nagy hangsúlyt kapott. Sok fajta azóta munkanélkülivé vált (hiszen nem kell lovaskocsit kísérni vagy épp marhákat a vágóhídra terelni), így aztán napjainkra a küllem még fontosabb lett, és a munkakutyák egy része családi kedvenccé vedlett át.

Amikor egy fajtára gondolunk, akkor – elsősorban a médiának köszönhetően – megjelenik bennünk egy kép, például hogy egy retriever mennyire könnyen kezelhető, vagy hogy egy vizslának milyen hatalmas mozgásigénye van. Hajlamosak vagyunk azt feltételezni, hogy a fajtának minden egyedére ugyanazok a tulajdonságok jellemzőek, és ha egy olyan kutyát viszünk haza, akkor biztos olyan is lesz. 

A fajtáknak vannak jellemző tulajdonságaik, de az egy fajtába tartozó kutyák között is nagy különbségek lehetnek

„A személyiség kifejezésnek sokféle köznapi használata van, a viselkedéstudományban azonban pontos definíciója van, és az egyedekre vonatkozik. Azaz csak egyednek, legyen az kutya vagy cserebogár lehet személyisége. Az egyed személyisége alatt olyan személyiségvonások összességét értjük, amelyek térben és időben állandóak, és ezért jellemzők az egyedre” – mondja dr. Miklósi Ádám, az ELTE Etológia Tanszékének vezetője, illetve annak a kutyaetológiai könyvnek a szerzője, melyet blogjában Bekoff is idéz. „Kutyafajtákra gondolva az a helyes megfogalmazás, hogy vannak olyan viselkedési jellegek, amelyek esetében ezek a fajták különböznek. Így például vannak jellemzően aktívabb és kevésbé aktív fajták, de itt is előfordulhat, hogy az aktívabb fajta egyes egyedei kevésbé aktívak, mint a kevésbé aktív fajta aktívabb egyedei. Figyelembe kell ugyanis venni, hogy a kinézetbeli hasonlóság ellenére (ami a legfontosabb szempont a tenyésztésben), az egyazon fajtához tartozó kutyák viselkedésében nagy eltérések lehetnek. Ezért nem szerencsés a gazdáknak azt sugallni, hogy egy fajta egyenlő egy típussal.”

Válasszunk tudatosan!

Akinek kutyája van, és gyakran találkozik más kutyásokkal, az valószínűleg pontosan tudja, hogy milyen nagy eltérések lehetnek az azonos fajtába tartozó kutyák viselkedése között. Nekem például egy francia juhászkutyám van (beauceron), amelyikre alapvetően az a jellemző, hogy idegenekkel szemben tartózkodóan viselkedik. Ehhez képest mindig nagy meglepetést okoz, amikor Nathan gond nélkül elkezd barátkozni másokkal, hamarabb, mint a golden retrieverem.

Amikor tehát kutyát szeretnénk, akkor ne csak a fajtát vegyük figyelembe, hanem a konkrét (kis)kutya tulajdonságait, mondjuk el a tenyésztőnek vagy az örökbe adó szervezetnek, hogy milyen céllal szeretnénk kutyát (például partnert a sportoláshoz vagy egy nyugodt társat a gyerekek mellé), és ő ezek alapján ki tudja választani, hogy melyik az, amelyik a leginkább hozzánk való. Ezzel lényegesen megkönnyíthetjük az életünket, és elkerülhetjük a kellemetlen meglepetéseket – például azt, amikor a könnyen kezelhető fajtájúnak gondolt kutyuskánk a valóságban meglepően önfejűnek bizonyul.

Neanderthal Inheritance

Neanderthal Inheritance

Source:

Source: AEON The Neanderthal renaissance

Rebecca Wragg Sykes

is a Palaeolithic archaeologist and heritage consultant, specialising in Neanderthals. Her first book Kindred: 300,000 Years of Neanderthal Life and Afterlife is due for publication in 2019. She lives in Wales.

4,400 words

Edited by Sally Davies

By the 1960s, it was widely believed that Neanderthals were primarily carnivores who dwelt in frigid surroundings with very little vegetation. This was in part based on ignorance of Indigenous plant use in comparable habitats, but also because anthropology was male-dominated, and particularly focused on the lives of big-game hunters. Reactions against this perspective, however – including from feminist scholars – pointed out that a significant proportion of calories came from the ‘slow and steady’ second part of the hunter-gatherer equation: not only plants, but small-game hunting and fishing. In reality, people who live by foraging are deeply embedded in their environment, and everyone, including women, elders and young children, takes part.

These shifts in perspective brought plants and creatures such as birds back into the picture, but their evidence among Neanderthals remained elusive in the archaeological record. The nadir came during the 1980s, when scholars proposed that the vast amounts of bones and teeth in Neanderthal sites weren’t even from hunting, but scavenging. This left Neanderthals skulking around the fringes of hyena or lion kills, grabbing scant scraps without invoking the ire of ‘true’ predators.

However, this scenario was also overturned as archaeology began to mature as a discipline throughout the final decades of the 20th century. A new array of methods, and a growing awareness of bias due to outdated excavation and collection standards, brought our perception of Neanderthals into much sharper resolution. In the decades since, evidence from hundreds of sites has been meticulously parsed and amassed, revealing the Neanderthals as top-level team hunters. They took on mighty beasts including bears, rhinos and possibly mammoth, using finely honed wooden spears for close-quarters jabbing; others were likely thrown like javelins. The myth of speedy critters such as birds or rabbits being out of reach has been crushed, while seafood was at least sometimes on the menu. Strand-line gathering was practised, whether for shellfish or the odd washed-up marine mammal, and maybe freshwater fish.

Plants supplemented this varied carnivorous diet. Neanderthals made their living across a huge geographical area, from North Wales down to Palestine, and eastwards nearly halfway across Siberia, so it’s no wonder we find preserved morsels of figs, olives, pistachios and date palm in caves across the Mediterranean and West Asia. In archaeological sediments and on stone tools, remnants of tubers (wild radish, water lily) and seeds (wild cereal, peas and lentils) have also been discovered. All this tells us that Neanderthals were very likely chowing down on cooked food more diverse than meat. Perhaps food was as important to social identity tens of millennia ago as it is for us today.

What if the first Homo sapiens walked into dark caves to find walls blazing with ancient visions?

Aside from the visceral satisfaction of a full belly, did the Neanderthals experience passions at a more profound level? Were they capable of self-expression, and abstract thought? Archaeologists are nudging closer to affirmative answers. Paintings found at three caves in Spain – La Pasiega, Maltravieso and Ardales – include red-daubed stalactites and flowstone, a clean vertical line and, most enchanting of all, a stencilled silhouette of a hand. Just recently, scientists applied a dating technique measuring the radioactive decay of uranium-thorium in the minerals encrusting the paintings, thereby revealing a minimum age. The results were startling: the oldest ranged from 67,000-52,000 years, appearing some 20,000-7,000 years before we believe that H sapiens arrived in Europe. For many scholars, this represents strong evidence that Neanderthals were responsible. (Others are more hesitant: dating millimetre-thick flowstone layers is complex, and some results suggested contamination.)


A Cave art at La Pasiega, Spain is dated by researchers at the University of Southampton to between 67,000 and 52,000 years old.

Studies across Europe had already found that many cave paintings rested on a substratum of red hand-stencils, lines and dots. The line image at the La Pasiega site seems connected to a ladder-like form, although the other parts might have been added later. Even so, the findings raise the possibility that the first H sapiens entering Europe’s caves walked into the darkness to find, not blank canvases, but walls blazing with ancient visions. If genuine, these discoveries have exposed a hidden layer of Neanderthal self-expression, sitting beneath the more famous Upper Palaeolithic oeuvre. Perhaps painting was even something our species actually learned, rather than being the independent wellspring of art.

Some of the Neanderthals’ creations carry more than a hint of the eldritch – structures so old that their attribution is unquestionable. In the 1990s, hundreds of metres deep inside the Bruniquel cave in southern France, researchers uncovered stalagmites snapped off and arranged into two rings, encircling smaller piles. But it was only in 2013, after a suspiciously old radiocarbon measurement was taken, that researchers began studying them in detail. Over 174,000 years ago, it seems that Neanderthals walked into the isolated chamber and carefully built these large circular structures. More than 400 pieces from the central parts of the stalagmite columns were placed in layers, some balanced on top of each other, others standing in parallel. Many had been extensively burned, and blazes had been kindled in the small piles. At least some of the fuel was bone, potentially including bear, which isn’t easy to set and keep alight. So far there are no artifacts, and no explanation for the rings, but these structures would have taken time and planning to create, and the foresight to provide sufficient illumination underground. Research is ongoing – most excitingly, to see what lies beneath the floor, entombed in calcium carbonate – but Bruniquel has already opened a vista onto a Neanderthal mind as elaborate as our own.

It’s important to add a note of caution to all this, since Palaeolithic archaeology is still full of ‘unknown unknowns’. It’s true that we have no fossil evidence for H sapiens west of the Danube delta – never mind southern Iberia – before 45,000 years ago, which leaves Neanderthals as the chief suspects for the paintings. But absence of bones does not prove absence of hominins, and we know that H sapiens were making their way into the Levant by at least 150,000 years ago. So the case is not entirely closed for the cave art, even if the 3D creation at Bruniquel seems secure. Still, these revelations have radically altered our understanding, and expectations, of what Neanderthals did in their daily lives – which now includes the possibility of more esoteric practices.

Alongside the archaeological evidence, genetics is the second pillar of the recent scientific reappraisal of the Neanderthals. Increasingly refined data suggest that humans and Neanderthals shared an ancestor around 800,000-700,000 years ago, before they split along different evolutionary paths. This process could even have taken place within genetically diverse but interconnected hominin populations that evolved in Africa, and moved out from there to the Near East and farther lands.

In 2010, researchers analysed the genome of three Neanderthal individuals, and compared the data with modern humans from various parts of the world. Based on genetic links, it seems that some time after 200,000 years ago, early H sapiens emerging from Africa interbred with Eurasia’s indigenous hominin inhabitants. That’s why the genomes of all living people – with the exception of those from sub-Saharan Africa – contain a small percentage of Neanderthal DNA. However it happened, the science is clear: to produce the amount of DNA surviving today, taking into account complex processes of selection against Neanderthal genes and less fertile hybrids, there must have been an awful lot of sex between the communities.

This finding rocked the scientific world, and shredded the ‘replacement without interbreeding’ story of the Neanderthals’ decline. Living people preserve a stunning 20 per cent, maybe more, of the Neanderthal genome, albeit as a somewhat tattered archive that’s distributed between different populations. Even more surprisingly, it’s not Western Europeans who have the most Neanderthal DNA: East Asians have up to a fifth more. There were also numerous phases of hybridisation. The earliest known encounter happened more than 220,000 years ago, when a female ancestor of H sapiens mated with a male Neanderthal – much earlier than other known interbreeding between the two groups. At the other end of the temporal scale, the jaw of a human who lived 40,000 years ago in Romania reveals that he counted a Neanderthal among his ancestors just four to six generations back – right at the time when they were about to disappear from the fossil record.

The girl was a first-generation hybrid: her mother Neanderthal, her father Denisovan

In the same year as the Neanderthal DNA announcement, humans were introduced to another long-lost cousin we didn’t even know we had – and with whom we’d also merged. Since the 1970s, Russian scientists had been excavating the Denisova cave in western Siberia. Among thousands of bones they’d found was the tip of a child’s pinky finger. Genetic analysis published in 2010 revealed it to be an entirely unknown hominin population. The ‘Denisovans’, as they were called, were a ‘sister’ group to the Neanderthals, branching off around 600,000-430,000 years ago. A sizeable proportion of the Denisovan genome survives in us, and scientists have pieced together evidence that we interbred with them multiple times. Many more Denisovans have now been identified at the same site, from tiny scraps of bone or even DNA in the cave sediment itself. Yet we still have no idea what these people really looked like, beyond the fact some had dark eyes and skin.

In yet another twist, it turns out the Neanderthals and Denisovans were close contemporaries, living in the same region for thousands of years. During protein sampling aimed at locating more hominins among unidentified bones from the cave, one stood out. Researchers had chanced upon a bone fragment from a girl, probably a teenager, who was a first-generation hybrid: her mother a Neanderthal, her father a Denisovan. Even more incredibly, her paternal ancestry revealed an even older genetic record of mixing between these populations, hundreds of generations before.

It’s hard to square these narratives of repeated contact and reproduction with the archaeological record of the Neanderthals’ sudden demise. Everything we’ve found, whether from new excavations or improved dating, has drawn the noose tighter around that period of time around 40,000 years ago, when Neanderthals’ distinctive skeletal and material remains disappear. Given the chronological resolution that’s possible so far back, this is tantamount to an almost simultaneous vanishing across their entire geographical range. Yet the genetics shows that they were not extinguished, but rather engulfed in a human flood. H sapiens weren’t their executioners so much as their assimilators.

It’s not clear how or why the encounters that led to interbreeding took place. For starters, we shouldn’t treat Neanderthals or early H sapiens as monolithic entities; in reality, the population dynamics must have been enormously varied, with groups spreading out and mingling in different ways in different places. What about the result of all these trysts: with whom, and how, were the hundreds, if not thousands, of hybrid babies raised? Basic anatomy, combined with neurocognitive and psychological research, both imply that these youngsters needed care, support and love to survive and flourish – just as our own offspring do. But does this mean that entire groups merged physically and culturally, or that our mixed genetic dossier is the byproduct of a profusion of ‘one-offs’, accidental encounters that accumulated over 100,000 years? At present we can make only hazy guesses.

Beyond the advances in science, these changes in perspective on Neanderthals are the fruit of a longstanding cultural obsession. Since 1856, we have been trying to capture the likeness of these people – and yes, Neanderthals must indeed be seen as people, albeit of another kind. Yet the portrait is never finished. With each new archaeological advance, they edge closer and closer to us, feeding our hunger to know ever-more intimate details. Yet something lurks: niggling, uncanny. Evolution has primed us with extraordinarily sensitive face-detection capabilities, but this comes with a deep-brain warning system. When faces are not obviously fake, but fall short of hyper-realistic, they snag our reflex recognition while also triggering alarm.

This disquieting aversion to aberrance, the so-called ‘uncanny valley’ effect, was observed in people’s reactions to robots as far back as the 1970s. One explanation for the ‘dyspathy’ it evokes is a protective instinct, helping us recognise threats from cadavers or the diseased. The Neanderthals induce something similar, a mirror image of us in so many ways, yet somehow aslant. Their liminal quality, at some anthropic edge, produces an uneasy tension. We mentally flinch at the same time as being drawn towards them, because they force us to reconsider how we mark the borders of humanity.

This is why the hand stencil at Maltravieso is so breathtaking. It’s a manifestation of corporeality, proof that all those untouchable skeletons in museum cases were once real, vital bodies. Until that point, the rare cases of Neanderthal ‘trace fossils’ were little more than blurred outlines, mostly footprints at just a few sites. A single, clear fingerprint was found around 50 years ago during industrial open-cast mining in the foothills of the Harz Mountains in Germany. It was imprinted on the surface of a piece of soft birch tar. Cooked from bark, this is the world’s first synthetic material, a natural glue used to join stone tip to wooden handle. The Neanderthal who sat fashioning the tool 80,000 years ago, wreathed in astringent fumes, was probably thinking about the near future – how much longer the stone edge would last, when the season would shift – little knowing these actions would stretch to a world thousands of generations later, as a single finger pressed a whorl into the softened tar.

Corporeal encounters with the Neanderthals can bewitch us because they perform a sort of temporal sorcery. Hands pressed on cave walls seem to imbue the rock with the memory of warmth; bodies moving against each other 50,000 years ago become time-travellers in the blood of their descendants. The changing visions we have conjured in our imaginations are made manifest in how Neanderthals are represented in artistic recreations – from the strikingly bestial and depressed-looking creatures of the Victorian era, to the exquisite digital portraits of the contemporary artist Tom Björklund, whose Neanderthals certainly think, feel and dream as much as we do.

There is no cognitive chasm between us, just as there was no reproductive barrier

Today, the story of the Neanderthals is still in flux. It is only 10 years since the watershed DNA discovery and subsequent demolition of their status as evolutionary dead-losses. We now know there were no Neanderthal endlings, no last lonely survivors. Many researchers now question whether we can even think of them as a different species. All the new evidence calls into question the way we have theorised their lives, often involving lists of standards they must meet to be considered genuinely human. ‘Modern’ behaviour has always been a very particular version of how we like to think of ourselves. A classic example – still being played out in arguments over re-excavation of the La Chapelle site – is at what point are we prepared to grant Neanderthals a conception of death? Too often, clear evidence for special treatment of the deceased is not enough; only a perfectly cut grave, the epitome of ‘proper’ Christian burial, is considered proof of meaningful social practices.

The next step is to kick our habit of narcissism and self-projection, and try to illuminate the Neanderthals on their own terms.

The origins of human language

Paleolithic Continuity Paradigm

The origins of human language

(excerpt)

Source:

Date de parution : 01/2017
Éditeur : Edizioni dell’Orso
Nombre de pages : 64
ISBN : 978-88-6274-727-1

FRANCESCO BENOZZO & MARCEL OTTE

SPEAKING AUSTRALOPITHECUS

A New Theory on The Origins

of Human Language

pp 49-50:

Conclusions

It is crucial to bear in mind the following assertion recently made by two eminent paleoanthropologists: The relationship between modern anatomy, cognition, culture and language is a complex one, and cannot be captured by a single saltationary event, let alone by a single ‘gene’ acquired at a specific moment in our evolutionary history, leaving unambiguous traces in the fossil or archaeological record. This myth of a ‘modern human revolution’ is now totally rejected by paleoanthropologists and archaeologists, but it is disturbing to see it persisting – explicitly or implicitly – in discussion of language and cultural evolution…

Also Seyfarth & Cheney (2016) insist on this point, asserting that, “despite their differences, human language and the vocal communication of nonhuman primates share many features”. These common features suggest that “during evolution the ancestors of all modern primates faced similar social problems and responded with similar systems of communication and cognition”. In this respect, “when language later evolved from this common foundation, many of its distinctive features were already present”.

According to Hillert, 2015, “Australopithecus was already able to use […] referential vocalizations (possibly in combination with facial expressions and gestures) to display basic emotions and perceptions”; and Kimbel & Villmoare, 2016, state: “A fresh look at brain size, hand morphology and earliest technology suggests that a number of key Homo attributes may already be present in generalized species of Australopithecus, and that adaptive distinctions in Homo are simply amplifications or extensions of ancient hominin trends”. Their conclusion is that “the expanded brain size, human-like wrist and hand anatomy, dietary eclecticism and potential tool-making capabilities of ‘generalized’ australopiths root the Homo lineage in ancient hominin adaptive trends, suggesting that the ‘transition’ from Australopithecus to Homo may not have been that much of a transition at all”. Bringing together the PCP, Chomsky’s innatism, and the refusal of a conception of languages as evolving organisms, more concrete elements for inferring the existence of an articulated language in early humans from the Plio-Pleistocene can be offered by the four elements of deductive evidence indicated before [1) the lithic-geolinguistic correlation, 2) the millennial stability of languages, 3) the new discovers about the language of animals, and 4) the process of human world formation], linked to paleontological-archaeological considerations on Australopithecus [concerning its 4) anathomy, 5) habitat, 7) tools, and 8) bone remains]

As linguists and prehistorians working in the epistemological frame offered by the Paleolithic Continuity Paradigm, we can positively answer to the question luminously posed 20 years ago by Tobias. We would then point out the three following conclusions:

(1) Homo was born loquens (2.5 million years ago); (2) languages appeared with Homo himself; 3) language existed much earlier on (before 2.5 million years ago), with Australopithecus.

Narrative processing

A cross-modal hub for narrative processing

copy

Posted on December 3, 2018

Stories are focused on the protagonist Excerpts from: Journal of Cognitive Neuroscience Volume30 , No. 9

Storytelling Is Intrinsically Mentalistic: A Functional Magnetic Resonance Imaging Study of Narrative Production across Modalities

https://www.mitpressjournals.org/doi/full/10.1162/jocn_a_01294

my notes in: [ ]

Abstract

 People utilize multiple expressive modalities for communicating narrative ideas about past events. The three major ones are speech, pantomime, and drawing. The current study used functional magnetic resonance imaging to identify common brain areas that mediate narrative communication across these three sensorimotor mechanisms. In the scanner, participants were presented with short narrative prompts akin to newspaper headlines (e.g., “Surgeon finds scissors inside of patient”). The task was to generate a representation of the event, either by describing it verbally through speech, by pantomiming it gesturally, or by drawing it on a tablet.In a control condition designed to remove sensorimotor activations, participants described the spatial properties of individual objects(e.g., “binoculars”). Each of the three modality-specific subtractions produced similar results, with activations in key components of the mentalizing network, including the TPJ,

[temporoparietal junction]

posterior STS [posterior superior temporal sulcus], and posterior cingulate cortex. Conjunction analysis revealed that these areas constitute a cross-modal “narrative hub”that transcends the three modalities of communication. The involvement of these areas in narrative production suggests that people adopt an intrinsically mentalistic and character-oriented perspective when engaging in storytelling, whether using speech,pantomime, or drawing.

INTRODUCTION

Theories of language origin can be divided into“vocal” and “gestural” models (McGinn, 2015;Arbib, 2012;Armstrong & Wilcox, 2007;MacNeilage & Davis, 2005;Corballis, 2002).Gestural models posit that manually produced symbols evolved earlier than those produced vocally and that speech was a replacement for a preestablished symbolic system that was mediated by gesture alone.Importantly, the kind of gesturing that gestural models allude to is“pantomime” or iconic gesturing. Iconic gesturing through pantomime is thought to have predated symbolic gesturing, passing through an intermediate stage that Arbib (2012)refers to as “proto-symbol.”

From a neuroscientific perspective, these theories of language origin establish a fundamental contrast between two different sensorimotor routes for the conveyance of language, namely,the audiovocal route for speech and the visuo-manual route for pantomime. Language is an inherently multimodal phenomenon, not least through the gesturing that accompanies speaking (Beattie, 2016;Kendon, 2015;McNeill, 2005).Humans have yet a third means of conveying semantic ideas, and that is through the generation of images, as occurs through drawing and writing (Elkins, 2001).We have argued elsewhere that the capacity for drawing is an evolutionary offshoot of the system for producing iconic gestures such as pantomimes (Yuan & Brown, 2014).Drawing is essentially a tool-use gesture that “leaves a trail behind” in the form of a resulting image. Overall, speech,pantomime, and image generation comprise a “narrative triad,”representing the three major modalities by which humans have evolved to referentially communicate their ideas to one another.

Perhaps, the most important function of language is the communication of narrative, conveying the actions of agents, or“who did what do whom.”

[MISTAKE IN ORIGINAL TEXT. CORRECTLY: “WHO DID WHAT TO WHOM” ]

Agency is one of the primary elements that is encoded in syntactic structure (Tallerman, 2015).Although word order varies across languages, 96% of languages place the subject (the agent) before the thing that the subject acts upon(Tomlin, 1986).Hence, an “agent first” organization of sentences seems to be an ancestral feature of language grammar (Jackendoff, 1999),and gestural models of language origin highlight this type of sentence organization as well (Armstrong & Wilcox, 2007). Although language is well designed to communicate agency through syntax, it typically does so in a multimodal manner, combining speech and gesture. A basic question for the evolutionary neuroscience of human communication is whether the conveyance of narrative is linked to specific sensorimotor modalities (vocal vs. manual) or whether there are cross-modal narrative areas in the brain that transcend these modalities. This question led us to design an experiment in which we would explore for the first time whether cross-modal brain areas mediate the communication of narrative ideas using speech,pantomime, and drawing as the triad of production modalities.

Most previous neuroimaging studies of cross-modal communication are perceptual, and we are not aware of production studies that have compared any pair of functions among speech,pantomime, and drawing in healthy adults.

Evolutionary Implications

Both vocal and gestural models of language attempt to account for the origins of syntax. As mentioned in the Introduction, language grammar seems to have an intrinsically narrative structure to it,being efficient at describing who did what to whom—in other words,agency. Standard subject–verb–object models of syntactic structure (Tallerman, 2015)essentially encapsulate the kinds of transitive actions that we examined in our headlines. A large majority of languages operate on an agent-first basis, putting the actor before either the action or the target of the action. To the extent that agency is one of the most fundamental things that is conveyed in grammars (and which is lacking in so-called proto-languages; Bickerton, 1995),then our results have application to evolutionary models of language.In particular, the imaging results that were obtained in the most purely linguistic condition (speech) were replicated almost identically in the nonlinguistic conditions of pantomime and drawing.This cross-modal similarity suggests that the capacity of syntax to represent agency can be achieved through nonlinguistic means employing essentially the same brain network.

A number of biological theories of language propose that syntax emerged from basic processes of motor sequencing (Arbib, 2012;Fitch, 2011;Jackendoff, 2011).Although this might account for grammar’s connection with object-directed actions—in other words, the gestural level of representation—it may not do justice to the sense of agency that is well contained in syntactic structure. Hence, we suggest that another important evolutionary ingredient in the emergence of syntax—beyond the “plot” elements contained in motor sequencing—would be the incorporation of circuits that mediate the sense of agency, not least“other” agency. To be clear, we are not arguing that the TPJ and pSTS are syntax areas. We are simply suggesting that, whereas circuits in the IFG [inferior frontal gyrus] more typically associated with syntax (Zaccarella & Friederici, 2017)might mediate the gestural level of language, the TPJ might have a stronger connection with agents in the overall scheme of language,discourse, and narrative. Agency can be conveyed linguistically through speech and sign, but it can also be conveyed nonlinguistically through pantomime (iconic gesturing) and drawing.

Conclusions

In this first three-modality fMRI study of narrative production, we observed results that suggest that people generate stories in an intrinsically mentalistic fashion focused on the protagonist, rather than in a purely gestural manner related to the observable action sequence. The same set of mentalizing and social cognition areas came up with each of the three modalities of production that make up the narrative triad, pointing to a common set of cognitive operations across modalities. These operations are most likely rooted in character processing, as related to a character’s intentions, motivations, beliefs, emotions, and actions. Hence,narratives—whether spoken, pantomimed, or drawn—seem to be rooted in the communication of “other-agency.”

Posted in English, ScienceTagged hub mentalistic storytelling

Darwin on expression of emotions

The Expression of the Emotions in Man and Animals (Wikipedia)

Author Charles Darwin
Country United Kingdom
Language English
Subject Evolutionary theory, human behaviour
Publisher John Murray
Publication date 1872

The Expression of the Emotions in Man and Animals is Charles Darwin‘s third major work of evolutionary theory, following On the Origin of Species (1859) and The Descent of Man (1871). Initially intended as a section of The Descent of Man, it was published separately in 1872 and concerns the biological aspects of emotional life. In this book, Darwin sets out some early ideas about behavioural genetics, and explores the animal origins of such human characteristics as the lifting of the eyebrows in moments of surprise and the mental confusion which typically accompanies blushing. A German translation of The Expression appeared in 1872; Dutch and French versions followed in 1873 and 1874. A second edition of the book, with only minor alterations, was published in 1890.

Before Darwin, human emotional life had posed problems to the western philosophical categories of mind and body.Darwin’s interest can be traced to his time as a medical student and the 1824 reprint of Sir Charles Bell‘s Anatomy and Philosophy of Expression which argued for a spiritual dimension to the subject. In contrast, Darwin’s biological approach links mental states to the coordination of movement, and allows cultural factors only an auxiliary role in the shaping of expression. This biological emphasis leads to a concentration on six emotional states: happiness, sadness, fear, anger, surprise and disgust. It also leads to an appreciation of the universal nature of expression, with its implication of a single origin for the entire human species; and Darwin points to the significance of emotional communication with children in their psychological development. Darwin sought out the opinions of some leading British psychiatrists, notably James Crichton-Browne, in the preparation of the book which forms his main contribution to psychology.[

Amongst the innovations with this book are Darwin’s circulation of a questionnaire (probably inspired by his cousin, Francis Galton) during his preparatory research; simple psychology experiments on the recognition of emotions with his friends and family; and (borrowing from Duchenne de Boulogne, a physician at the Salpêtrière) the use of photographs in his presentation of scientific information. Publisher John Murray warned Darwin that including the photographs would “poke a hole in the profits” of the book; and The Expression of the Emotions is an important landmark in the history of book illustration.

Epigenetics/endocrinology

source:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4071959/?fbclid=IwAR2xtUPKnqazgKP0vavon2wq8_0Pup64aKCkRMtpIYFQ7LNyUrS9LaMNe0k

Excerpts from “Epigenetics meets endocrinology” by Xiang Zhang and Shuk-Mei Ho

…1.We propose a three-dimensional model (genetics, environment, and developmental stage) to explain the phenomena related to progressive changes in endocrine functions with age, the early origin of endocrine disorders, phenotype discordance between monozygotic twins, rapid shifts in disease patterns among populations experiencing major lifestyle changes such as immigration, and the many endocrine disruptions in contemporary life.

2.The inherited variability is static and does not change in response to the environment. The acquired variability can be caused by an environmental factor such as u.v. radiation from the sun (exogenous) or reactive oxygen species generated during metabolism (endogenous). But once acquired these effects are permanent and irreversible. Thus, inherited and acquired variability, either alone or in concert, cannot fully explain the high degree of variability and the reversibility of the endocrine system in response to the environment.

3. Most cells or organs have various degrees of phenotypic plasticity, whereby the phenotype expressed by a genotype is dependent on environmental influences

Collectively, these findings indicate that nongenetic factors, including the environment, are important determinants of variability in endocrine function and risk of disorders. Endocrine glands and their target organs, because they function to maintain homeostasis in the body, must be highly responsive to environmental changes.

4. A high degree of mismatch between the adaptive trait and the future environment, which includes aging, changes in lifestyle, or the introduction of new chemicals, pathogens, and pollutants, may increase the risk of developing disease. Prime examples are the strong correlations observed between hyponutrition and/or low birth weight with many endocrine disorders related to thyroid function, calcium balance, utilization of glucose, insulin sensitivity, and adrenal gland function (Vaag & Poulsen 2007, Hyman et al. 2009, Latini et al. 2009).

5. The mechanisms underlying the interactions of genetics and the environment, which produce an adaptive phenotype in an endocrine axis, remain elusive. However, a growing body of literature suggests that the missing connection resides in epigenetics, a pivotal mechanism of interactions between genes and the environment (Jaenisch & Bird 2003, Cook et al. 2005, Jirtle & Skinner 2007, Tang & Ho 2007, Vaag & Poulsen 2007, Ling & Groop 2009; Fig. 1).

6. Epigenetics links genetics with the environment in endocrine function. Hormone levels vary in response to internal and external environmental changes. Epigenetics, in response to exogenous and endogenous environmental cues, defines active and repressed domains of the genome. These responses explain the high phenotypic plasticity observed in the endocrine system, in which different genetic programs are executed from the same genome based on changes in the environment.

7. Epigenetic modifications defined as heritable changes in gene function that occur without a change in the nucleotide sequence (Bird 2007, Goldberg et al. 2007, Berger et al. 2009). They are mitotically and transgenerationally inheritable (Rakyan et al. 2002, 2003, Hitchins et al. 2007) and potentially reversible (Bannister & Kouzarides 2005, Weaver et al. 2005). The most studied mechanisms known to affect the epigenome are DNA methylation, histone modification, and aberrant expression of microRNAs (miRNAs; Esteller 2005). These processes along with other epigenetic events determine when and whether various sets of genes are expressed in a tissue or cell.

8. Histones are special proteins that facilitate the packaging of the DNA into nucleosomes, the basic building block of the chromatin. Posttranslational modifications such as acetylation, methylation, phosphorylation, sumoylation, and ubiquitination occur at specific residues in histones N-terminal tails (Cosgrove et al. 2004). These modifications determine whether the DNA wrapped around histones is accessible to the transcriptional machinery… In most instances, histone modifications work hand-in-hand with DNA methylation to achieve short- and long-term changes in transcriptional programs through transient or permanent reorganization of the chromatin architecture (Kondo 2009; Fig. 2).

9. DNA methylation and histone modification are two major epigenetic mechanisms that corroborate in regulating endocrine-related gene expression. Packaging genes into active or inactive chromatin determines whether they are transcriptionally accessible or not. The N-termini of histones have specific amino acids that are sensitive to posttranslational modifications, which contribute to chromatin status.

10. Epigenetics also plays important roles in regulating thyroid hormone and retinoic acid metabolism. For example, the expression of the sodium iodide symporter (SLC5A5), which is responsible for the uptake of iodine in the thyroid, was shown to be regulated by cytosine methylation of its promoter (Venkataraman et al. 1999, Smith et al. 2007).

11. As a general observation, epigenetic dysregulation of the expression of type I receptor genes is closely linked to endocrine-related disorders including cancers of the breast, prostate, testis, and endometrium. DNA methylation dysregulates androgen receptor expression in prostate and endometrial cancer (Kinoshita et al. 2000, Sasaki et al. 2000), estrogen receptor-α in breast cancer (Yoshida et al. 2000, Archey et al. 2002, Adams et al. 2007, Champagne & Curley 2008), estrogen receptor-β in ovarian, prostate, and breast cancer (Zhao et al. 2003, Zhu et al. 2004, Zhang et al. 2007, Zama & Uzumcu 2009), and progesterone receptor in endometrial cancer (Sasaki et al. 2003).

12. Peptide hormones are another major class of hormones, which have a broad spectrum of action, including regulation of energy metabolism (e.g. insulin), adiposity (e.g. leptin), growth (e.g. GH), and differentiation (e.g. FSH).

Disruption of the synthesis of peptide hormones or their cognate receptors by epigenetic events often leads to metabolic changes (e.g. obesity and metabolic syndrome; Plagemann et al. 2009) and abnormalities in neuropsychological behavior (e.g. autism and alcohol dependence; Gregory et al. 2009, Hillemacher et al. 2009), as opposed to cancer, the predominant disorder for epigenetic dysregulation of steroid hormones and their receptors (Widschwendter et al. 2004).

…Notably, epigenetic regulation of genes encoding peptide hormones or their receptors is largely related to developmental stage- and tissue-specific function or the development of a metabolic or neural disorder. For example, in cultures of mouse embryonic stem cells, the hypermethylated promoter of the insulin gene undergoes demethylation as these cells differentiate into hormone-producing cells; and in both the mouse and human insulin gene promoters, the CpG sites are demethylated in insulin-producing pancreatic β-cells but not in other tissues without insulin expression (Kuroda et al. 2009).

13. In a recent study of autism-spectrum disorders, hypermethylation of the gene promoter encoding the oxytocin receptor was found to be associated with a reduced level of mRNA expression and was significantly associated with autism (Gregory et al. 2009). In another report, significant alterations of the mRNA expression and promoter-related DNA methylation of vasopressin were reported in patients with alcohol dependence (Hillemacher et al. 2009).

At the organismal level, the functioning of an endocrine axis involves multiple endocrine organs: for example, the hypothalamo–pituitary-gonadal axis comprising at least three hormone-producing tissues and many target tissues. The coordination of the entire axis, representing the first dimension of regulation controlled by genetic programs, is complex and meticulously well controlled. The interaction of these programs with the environment produces variable epigenomes, greatly amplifying the complexity of interaction and outcomes. These interactions can be viewed as the second dimension of influence…Finally, we will emphasize the effects of lifespan events that have strong modifying influences on epigenetics and pay special attention to windows of susceptibility during human development from conception to death.

14. Genetics, environment, and stages of lifespan development interact in a three-dimensional space to create discordant endocrine phenotypes (epigenomes) from an identical genetic background (a single genome).

A widely studied area of epigenetics–environment– lifespan interactions is the relationship between birth weight and disease in later life. Animal studies have demonstrated that retardation of intrauterine growth results in progressive loss of β-cell function and the eventual development of type 2 diabetes in the adult. This association directly links chromatin remodeling with suppression of gene transcription (Simmons 2009).

15. A review of human studies also indicated an inverse relationship between birth weight and susceptibility to endocrine metabolic disorders such as insulin resistance, type 2 diabetes, hyperlipidemia, and obesity (Godfrey 2006).

Insulin resistance is another example of epigenetic dysregulation resulting in the loss of function in an endocrine axis over time when it is constantly challenged by environmental changes such as specific dietary deficits. It is the condition in which normal amounts of insulin are insufficient to produce a normal insulin response from insulin-sensitive organs/tissues such as the liver, muscle, and adipose tissue, which all play an important role in the etiology and clinical course of patients with type 2 diabetes, high blood pressure, or coronary heart disease (Reaven 1993).

16. Summary and perspectives
It has become apparent that genetics alone is insufficient to explain the dynamic and complex interdependent relationships between the endocrine system and endogenous and exogenous environmental changes. … Epigenetics serves as a mechanism mediating the continuous `editing’ of the genome or epigenetic marks laid down in early life by exposures and experiences during later life. This paradigm has expanded the static and gene-centric view of phenotypic attributes to a more plastic and adaptive view molded by epigenetics. To fully understand the impacts of epigenetics on endocrine function and vice versa, we need a genome-wide search for plasticity genes or loci directly responsive to a specific environmental stimulus. To achieve this goal, current research is applying high-throughput investigative technologies to uncover global changes in the methylome(s), miRNA signatures, and the histone codes defining the interplay and advanced informatics to produce biologically meaningful data and conclusions. To advance these investigations, our focus should be placed on two commonly raised questions: 1) whether epigenetic changes induced by environmental exposures or lifestyle choices in one generation can be passed to the next and 2) whether these `inherited’ changes can be reversed upon removal of the exposures or through lifestyle modifications. Answers to the first question are of paramount importance to the primary prevention of endocrine disorders such as obesity, and answers to the second would open doors to the use of epigenetic drugs or interventions for the reversal of endocrine disorders with a strong epigenetic etiology. The opportunities of applying epigenetics to the prevention and treatment of endocrine disorders are limitless and certainly will emerge rapidly in the near future.