Consapevolezza del momento della propria morte

Proseguono - e sono sempre più dettagliati - gli studi su che cosa succede realmente   quando si muore. 
Sono stati scritti numerosi libri romanzati sulle esperienze cosiddette di "pre morte"  (NDE: Near Death Experience) e su quelle "fuori dal proprio corpo" (Out of Body Experience). 
Oggi sono disponibili i primi risultati di uno studio Anglo-Americano-Austriaco su 2060 casi d'arresto cardiaco occorsi in 15 ospedali, effettuato nel 2008 e pubblicato sulla rivista 'Resuscitation' (Rianimazione).
I risultati scientifici (come sempre) sono molto meno 'appariscenti, sensazionali ed avventurosi' di quelli riportati dalla fantascienza non informata dei fatti reali. Questo non li priva di un risvolto in qualche modo affascinante, oltre che di estremo interesse scientifico.

In sintesi:

- il 39% dei pz che hanno sperimentato - attraverso un arresto cardiaco - quel fenomeno potenzialmente reversibile che è la soglia della morte, riferisce una sensazione di 
consapevolezza, ma non sa citare gli eventi accaduti.

- Il 46% di coloro che hanno avuto una sensazione di consapevolezza e che sono riusciti a portare a termine una più completa intervista, riferiscono una vasta gamma di ricordi, nessuno dei quali però compatibile con il fenomeno letterario della NDE (esperienza di 
pre-morte): tra quelli riferiti sono incluse esperienze spaventose e persecutorie.
Solamente un

- 9%  ha riportato esperienze sovrapponibili a NDE ed uno sparuto

- 2% ha riferito una piena consapevolezza compatibile con quella che la letteratura ha definito OBE (Out of Body Experience), accompagnata dalla descrizione esplicita di ciò che 
aveva 'udito' e 'visto' nel corso del processo.

Discussione.

C'è ancora molto d'incompreso, evidentemente ancora da scoprire ed indagare, anche se riguarda solamente un ridottissimo campione del 2%... 
Specialmente se consideriamo che il cervello smette di funzionare dopo un breve periodo (20- 30 secondi) di mancanza d'ossigeno (ipossia) determinato dal mancato battito cardiaco (arresto) e che non riprende le proprie funzioni se non dopo la ripresa dell'attività cardiaca. 
In più, alcuni di questi straordinari episodi (documentati scientificamente usando stimoli sonori  durante l'arresto) si sono verificati nell'arco di 2-3 minuti di mancanza d'attività e le esperienze visive riportate sono state verificate come realmente avvenute dallo staff presente.
E' indubbiamente una materia per pochi: anestesisti, rianimatori, ed eventualmente pochi appassionati. Questi ultimi è meglio che si limitino a leggere, evitando di esprimere proprie opinioni fantascientifiche. 


The human mind and 

consciousness at the time of death 



 The results of a four-year international study of 2060 cardiac arrest cases across 15 hospitals concludes the following.

The themes relating to the experience of death appear far broader than what has been understood so far, or what has been described as so called near-death experiences. 

In some cases of cardiac arrest, memories of visual awareness compatible with so called out-of-body experiences may correspond with actual events. 
A higher proportion of people may have vivid death experiences, but do not recall them due to the effects of brain injury or sedative drugs on memory circuits. 
Widely used yet scientifically imprecise terms such as near-death and out-of-body experiences may not be sufficient to describe the actual experience of death.

Recollections in relation to death, so-called out-of-body experiences (OBEs) or near-death experiences (NDEs), are an often spoken about phenomenon which have frequently been considered hallucinatory or illusory in nature; however, objective studies on these experiences are limited. 

In 2008, a large-scale study involving 2060 patients from 15 hospitals in the United Kingdom, United States and Austria was launched. 
The AWARE (AWAreness during REsuscitation) study, sponsored by the University of Southampton in the UK, examined the broad range of mental experiences in relation to death. 
Researchers also tested the validity of conscious experiences using objective markers for the first time in a large study to determine whether claims of awareness compatible with out-of-body experiences correspond with real or hallucinatory events. 
Dr Sam Parnia, Assistant Professor of Critical Care Medicine and Director of Resuscitation Research at The State University of New York at Stony Brook, USA, and the study's lead author, explained: "Contrary to perception, death is not a specific moment but a potentially reversible process that occurs after any severe illness or accident causes the heart, lungs and brain to cease functioning. If attempts are made to reverse this process, it is referred to as 'cardiac arrest'; however, if these attempts do not succeed it is called 'death'. In this study we wanted to go beyond the emotionally charged yet poorly defined term of NDEs to explore objectively what happens when we die." 

Thirty-nine per cent of patients who survived cardiac arrest and were able to undergo structured interviews described a perception of awareness, but interestingly did not have any explicit recall of events. 
"This suggests more people may have mental activity initially but then lose their memories after recovery, either due to the effects of brain injury or sedative drugs on memory recall," explained Dr Parnia, who was an Honorary Research Fellow at the University of Southampton when he started the AWARE study. 

Among those who reported a perception of awareness and completed further interviews, 46 per cent experienced a broad range of mental recollections in relation to death that were not compatible with the commonly used term of NDE's.

These included fearful and persecutory experiences. 

Only 9 per cent had experiences compatible with NDEs and 2 per cent exhibited full awareness compatible with OBE's with explicit recall of 'seeing' and 'hearing' events. 

One case was validated and timed using auditory stimuli during cardiac arrest. 
Dr Parnia concluded: "This is significant, since it has often been assumed that experiences in relation to death are likely hallucinations or illusions, occurring either before the heart stops or after the heart has been successfully restarted, but not an experience corresponding with 'real' events when the heart isn't beating. 

In this case, consciousness and awareness appeared to occur during a three-minute period when there was no heartbeat. 

This is paradoxical, since the brain typically ceases functioning within 20-30 seconds of the heart stopping and doesn't resume again until the heart has been restarted. 
Furthermore, the detailed recollections of visual awareness in this case were consistent with verified events. 
"Thus, while it was not possible to absolutely prove the reality or meaning of patients' experiences and claims of awareness, (due to the very low incidence (2 per cent) of explicit recall of visual awareness or so called OBE's), it was impossible to disclaim them either and more work is needed in this area. 
Clearly, the recalled experience surrounding death now merits further genuine investigation without prejudice."

Further studies are also needed to explore whether awareness (explicit or implicit) may lead to long term adverse psychological outcomes including post-traumatic stress disorder. Dr Jerry Nolan, Editor-in-Chief of Resuscitation, stated: "The AWARE study researchers are to be congratulated on the completion of a fascinating study that will open the door to more extensive research into what happens when we die."

Results of the study have been published in the journal Resuscitation. 


Source:  University of Southampton. [October 08, 2014]

Perché il linguaggio è unicamente umano?

Why is language unique to humans?

New research published today in Journal of the Royal Society Interface suggests that human language was made possible by the evolution of particular psychological abilities. 

A mural in Teotihuacan, Mexico (ca. 200 AD) depicting a person emitting a speech scroll from his mouth, symbolizing speech [Credit: Daniel Lobo/WikiCommonjs]

Researchers from Durham University explain that the uniquely expressive power of human language requires humans to create and use signals in a flexible way. They claim that his was only made possible by the evolution of particular psychological abilities, and thus explain why language is unique to humans.

Using a mathematical model, Dr Thomas Scott-Phillips and his colleagues, show that the evolution of combinatorial signals, in which two or more signals are combined together, and which is crucial to the expressive power of human language, is in general very unlikely to occur, unless a species has some particular psychological mechanisms. Humans, and probably no other species, have these, and this may explain why only humans have language.

In a combinatorial communication system, some signals consist of the combinations of other signals. Such systems are more efficient than equivalent, non-combinatorial systems, yet despite this they are rare in nature. Previous studies have not sufficiently explained why this is the case. The new model shows that the interdependence of signals and responses places significant constraints on the historical pathways by which combinatorial signals might emerge, to the extent that anything other than the most simple form of combinatorial communication is extremely unlikely.

The scientists argue that these constraints can only be bypassed if individuals have the sufficient socio-cognitive capacity to engage in ostensive communication. Humans, but probably no other species, have this ability. This may explain why language, which is massively combinatorial, is such an extreme exception to nature’s general trend.

Authors: Thomas C. Scott-Phillips and Richard A. Blythe | Source:  The Royal Society [September 18, 2013]

Linguaggio & fabbricazione di utensili

Language and tool-making skills evolved at same time

Lo stato della ricerca , presso l'Università di Liverpool  porta a concludere che  il cervello sfrutta le medesime capacità per il linguaggio e per la costruzione di utensili: pertanto le due capacità umane potrebbero essersi evolute contemporaneamente. 

Research by the University of Liverpool has found that the same brain activity is used for language production and making complex tools, supporting the theory that they evolved at the same time.

Three hand axes produced by participants in the experiment. Front, back
and side views are shown [Credit: University of Liverpool]

I ricercatori dell'Università hanno controllato l'attività cerebrale di 10 esperti lavoratori della pietra (scheggiatori) sia mentre producevano un utensile, sia mentre affrontavano un test del linguaggio.

 Researchers from the University tested the brain activity of 10 expert stone tool makers (flint knappers) as they undertook a stone tool-making task and a standard language test.

Misurato il flusso ematico durante l'attività.

Brain blood flow activity measured

E' stato misurato il flusso ematico cerebrale  dei partecipanti, durante ambedue le attività, usando un ecodoppler grafia funzionale transcranica, che normalmente si impiega per valutare l'eventuale danno cerebrale post traumatico o pre operatorio.

 They measured the brain blood flow activity of the participants as they performed both tasks using functional Transcranial Doppler Ultrasound (fTCD), commonly used in clinical settings to test patients’ language functions after brain damage or before surgery.

I ricercatori hanno ottenuto pattern cerebrali correlati per ambedue le attività, il che suggerisce che ambedue sfruttano le medesime aree cerebrali. Il linguaggio e la capacità di produrre utensili di forma voluta dalle pietre sono attività considerate caratteristiche esclusivamente umane, che hanno avuto un'evoluzione di milioni di anni.

The researchers found that brain patterns for both tasks correlated, suggesting that they both use the same area of the brain.  Language and stone tool-making are considered to be unique features of humankind that evolved over millions of years.

The brain activity of an experienced flint-knapper is monitored using a
Transcranial Doppler Ultrasound, as he works the stone
[Credit: University of Liverpool]

Darwin fu il primo a suggerire  che l'uso di strumenti ed il linguaggio potessero essere andati incontro ad un'evoluzione contemporanea, in quanto entrambe le capacità dipendono  da una complessa pianificazione e dalla coordinazione di differenti azioni, ma fino ad oggi non si era data una prova convincente di questa possibilità.

Darwin was the first to suggest  that tool-use and language may have co-evolved, because they both depend on complex planning and the coordination of actions but until now there has been little evidence to support this.

Il dottor  Georg Meyer, del Dipartimento di psicologia Sperimentale sostiene  "Questo è il primo studio sul cervello che metta direttamente a confronto la confezione di manufatti complessi ed il linguaggio".

Dr Georg Meyer, from the University Department of Experimental Psychology, said:  “This is the first study of the brain to compare complex stone tool-making directly with language.

La manifattura di strumenti ed il linguaggio evolvettero parallelamente.

Tool use and language co-evolved

"Il nostro studio ha correlato i pattern del flusso ematico  nei primi 10 secondi  dall'inizio del compito, in ambedue le attività. Questo dimostra che ambedue le attività sono dipendenti dalle stesse aree cerebrali  ed è coerente con la teoria per cui la costruzione di strumenti complessi di pietra ed il linguaggio si evolvettero contemporaneamente e condividono analoghi percorsi nel cervello".

 “Our study found correlated blood-flow patterns in the first 10 seconds of undertaking both tasks.  This suggests that both tasks depend on common brain areas and is consistent with theories that tool-use and language co-evolved and share common processing networks in the brain.”

La dott.sa Natalie Uomini del Dipartimento di archeologia (Classics & Egiptology)  conferma che nessuno prima aveva misurato l'attività cerebrale mentre il soggetto costruiva uno strumento: si tratta di una prima volta, sia per la psicologia, sia per l'archeologia.

Dr Natalie Uomini from the University’s Department of Archaeology, Classics & Egyptology, said: “Nobody has been able to measure brain activity in real time while making a stone tool. This is a first for both archaeology and psychology.” 
I risultati sono pubblicati su  PLoS ONE.

The findings have been published in the journal PLoS ONE.

Source: University of Liverpool [September 02, 2013]