Friday, July 02, 2021

The rise and fall of elephants

MUSEUM FÜR NATURKUNDE, LEIBNIZ INSTITUT FÜR EVOLUTIONS- UND BIODIVERSITÄTSFORSCHUNG

IMAGE: ABOUT 4 MILLION YEARS AGO, AN *AUSTRALOPITHECUS ANAMENSIS* OBSERVED THE RICHNESS OF PROBOSCIDEANS IN WHAT IS NOW TURKANA, KENYA. FROM LEFT TO RIGHT *ANANCUS ULTIMUS*, *DEINOTHERIUM BOZASI*, *LOXODONTA ADAURORA*... view more
CREDIT: ILLUSTRATION BY JULIUS CSOTONYI

Based on fossil finds, we know that the vast majority of species that once inhabited the earth have become extinct. For example, there are about 5,500 mammal species living on the planet today, but we know of at least 160,000 fossil species, so for every mammal species living today, there are at least 30 extinct ones. We therefore know with great certainty that the lineages of living things come and go along immense time scales. But what factors cause these lineages to come into being and disappear is still an unsolved question.

To investigate this problem more closely, the research team focused on a charismatic group: the proboscideans, which include today's elephants, but also the extinct mammoths, mastodons and dinotheria. The history of the proboscideans is one of glory and decline. Although today there are only three species of elephants left in Asia and Africa, we know fossil more than 180 species of these animals, which also inhabited Europe, South America and North America. "In the past, more than 30 species of these giants lived on the planet at the same time, and many ecosystems were so productive and ecologically complex that it was not uncommon for three or more species of proboscideans to live together in the same ecosystem," explains Juan López Cantalapiedra, a researcher at the University of Alcalá in Spain and lead author of the new study.

However, as the researchers were able to show, proboscideans were not always so diverse. In the first 30 million years of their history, the group was limited to Africa and Arabia, which together formed an isolated continent that was not connected to Asia as it is today. Until then, the evolution of these animals was quite slow and the few existing species were ecologically quite similar. But about 22 million years ago, Afro-Arabia connected with Eurasia and the proboscideans spread all over the world. The new challenges faced by the lineages scattered outside Afro-Arabia caused the ecology of the group to multiply. Species emerged with different, highly diverse tooth shapes, including strange, shovel-shaped tusks. "This ecological diversity reduced competition between species and allowed several of them to live together in the same ecosystem at the same time," points out Fernando Blanco, a researcher at the Museum für Naturkunde Berlin. This marked the beginning of the golden age of proboscideans. "If the link between Afro-Arabia and Eurasia had not happened, or had happened at a different time, the evolutionary history of proboscideans would have been radically different," Blanco adds.

The new study also revealed the factors that determined the group's ultimate decline. Seven million years ago, modern savannah ecosystems spread across all continents, and because of this change, many proboscideans adapted to life in forested areas disappeared. At the same time, however, new forms appeared that were able to feed on less nutritious plant material such as wood and especially grass, which is typical of savannas. Today's elephants are among these evolutionary newcomers.

About 3 million years ago, the rules of the game changed again with the onset of the ice ages. In Eurasia and Africa, the extinction rate quintupled. But as the researchers were able to show, the extinction rate rose even further in Eurasia and America 160,000 and 75,000 years ago, respectively. Were humans responsible for this debacle? "At that time, Homo sapiens had not yet made it to these continents," Cantalapiedra explains. The analyses showed that the different phases of extinction were linked to the decline and rapid fluctuations in global temperatures as a result of the ice ages. "The impact of our ancestors probably contributed to the extinction of the few surviving species, such as the woolly mammoth, a little later."

###

Publication: Cantalapiedra JL, Sanisidro O, Zhang H, Alberdi MT, Prado JL, Blanco F, Saarinen J (2021) The rise and fall of proboscidean ecological diversity. Nature Ecology & Evolution. doi: 10.1038/s41559-021-01498-w

RUDN University chemists synthesize biodiesel from jatropha curcas plant

RUDN UNIVERSITY

Research News

RUDN University chemists have proposed a new method of producing fuel from Jatropha Curcas, a poisonous tropical plant. Natural minerals and a non-toxic additive from vegetable raw materials are used for that. The reaction efficiency is 85%. The fuel can be used in diesel internal combustion engines. The results are published in the International Journal of Green Energy.

Jatropha Curcas is a common plant in many tropical regions. Its seeds contain lots of oil, but they cannot be used agriculture because the oil contains toxins that are dangerous for people and animals. But the composition of jatropha oil is suitable for the manufacture of biodiesel. One of challenge of the processing the plant raw materials is to select sufficiently effective and safe catalysts. RUDN University chemists found a suitable catalyst and selected the optimal additive-a substance that improves the useful properties of the fuel.

"Mineral catalysts with a complex chemical composition, for example, zeolites -- calcium and sodium silicates, have performed well in biodiesel production from vegetable and animal fats. They are quite active, eco-friendly and can be reused. But biodiesel, like hydrocarbons, cannot be used without improving additives", Ezeldin Osman, PhD student at RUDN University.

RUDN University chemists decided to use furfural as an additive for diesel biodiesel. It is obtained from plant waste, such as sawdust or straw, it improves the characteristics of diesel fuel, in particular, its cetane number is an indicator of flammability.

As a first step, the researchers obtained biodiesel from Jatropha Curcas oil. To do this, they mixed the oil with three times as much methanol and added a catalyst -- minerals from the zeolite group, mainly thomsonite. The catalyst amount was 5 times lower than the oil. RUDN University chemists also tested other reaction settings, but the highest yield of biodiesels (up to 85% in the composition of the reaction products) was obtained at this ratio of reagents and a temperature of 75°C.

The main part of the experiment was the selection of the optimal amount of furfural to improve the characteristics of biodiesel. RUDN University chemists mixed biodiesel and the additive in equal quantities, in other variants they used twice as much additive as fuel, and vice versa. It turned out that the highest cetane number (64.1) is in fuel containing 66.6% of furfural. This is 4.3 units higher than that of biodiesels without furfural. In this ratio, the additive removes all compounds that impair flammability from the biodiesel, such as alcohols and carbonyl compounds. The achieved characteristics of biodiesel from jatropha kurkas allow it to be used in internal combustion engines in the future.

"The additive reduced the content of aluminum, sodium, magnesium, potassium, iron and other substances in biodiesel that form ash -- a non-combustible solid residue of fuel. This not only improves fuel performance, but also reduces the risk of engine wear. At the same time, furfural is a stable additive at high temperatures, environmentally friendly in production and application. We will continue experiments to improve diesel fuel with this substance", Tatiana Sheshko, PhD, the head of the Adsorption and Catalysis Laboratory at RUDN University.

Catalyzing the conversion of biomass to biofuel

Water in zeolites saves energy in the conversion of biomass into biofuel

TECHNICAL UNIVERSITY OF MUNICH (TUM)

Research News

IMAGE: PROF. LERCHER IN HIS LABORATORY AT THE DEPARTMENT OF CHEMISTRY AT THE TECHNICAL UNIVERSITY OF MUNICH. view more
CREDIT: ANDREAS HEDDERGOTT / TUM

Zeolites are extremely porous materials: Ten grams can have an internal surface area the size of a soccer field. Their cavities make them useful in catalyzing chemical reactions and thus saving energy. An international research team has now made new findings regarding the role of water molecules in these processes. One important application is the conversion of biomass into biofuel.

Fuel made from biomass is considered to be climate-neutral, although energy is still needed to produce it: The desired chemical reactions require high levels of temperature and pressure.

"If we are to do without fossil energy sources in the future and make efficient large-scale use of biomass, we will also have to find ways to reduce the energy required for processing the biomass," says Johannes Lercher, professor for Chemical Technology at the Technical University of Munich (TUM) and Director of the Institute for Integrated Catalysis at the Pacific Northwest National Laboratory in Richland, Washington (USA).

Working together with an international research team, Lercher has taken a closer look at the role of water molecules in reactions inside the zeolite's pores, which are less than one nanometer in size.

It all starts with acids

One characteristic of an acid is that it easily donates protons. Thus, when added to water, hydrochloric acid splits into negatively charged chloride anions, like those found in table salt crystals, and positively charged protons which attach themselves to the water molecules. This results in a positively charged hydronium ion, which looks to further pass on this proton, for example to an organic molecule.

When the organic molecule is "forced" to accept a proton, it tries to stabilize itself. Thus, an alcohol can give rise to a molecule with a double bond - a typical reaction step on the path from biomass to biofuel. The zeolite walls stabilize transitional states occurring during conversion and, thus, help to minimize the amount of energy required by the reaction to occur.

Zeolites acting as acids

Zeolites contain oxygen atoms in their crystal structure which already carry a proton. Like molecular acids they form hydronium ions through the interactions with water.

However, while hydronium ions disperse in water, they remain closely associated with the zeolite. Chemical pre-treatment can vary the number of these active centers and, thus, establish a certain density of hydronium ions in the pores of the zeolite.

The ideal zeolite for every reaction

By systematically varying the size of the cavities, the density of the active sites and the amount of water, the research team was able to elucidate the pore sizes and concentrations of water which best catalyzed selected example reactions.

"In general, it's possible to increase the reaction rate by making the pores smaller and raising the charge density," Johannes Lercher explains. "However, this increase has its limits: When things get too crowded and the charges are too close to one another, the reaction rate drops again. This makes it possible to find the optimum conditions for every reaction."

"Zeolites are generally suitable as nanoreactors for all chemical reactions whose reaction partners fit into the pores and in which an acid is used as a catalyst," emphasizes Lercher. "We are at the very beginning of a development with the potential to increase the reactivity of molecules even at low temperatures and, thus, to save considerable amounts of energy in the production of fuels or chemicals."

Participants in the research included the Catalysis Research Center at the Technical University of Munich, the US Institute for Integrated Catalysis at the Pacific Northwest National Laboratory, the Swiss Paul Scherrer Institute as well as the University of Yangzhou and the Qingdao Institute of Bioenergy and Bioprocess Technology in China. The work was funded by the Technical University of Munich and the US Department of Energy, Office of Science.

Eruption of the Laacher See volcano redated

Revised date of the Laacher See eruption 13,077 years ago provides crucial information about historical climate fluctuations at the end of the last Ice Age

JOHANNES GUTENBERG UNIVERSITAET MAINZ

Research News

IMAGE: 13,000-YEAR-OLD TREE TRUNK FROM THE VOLCANIC DEPOSITS OF THE LAACHER SEE ERUPTION IN THE VICINITY OF MIESENHEIM, GERMANY. view more
CREDIT: PHOTO/©: OLAF JÖRIS

The eruption of the Laacher See volcano in the Eifel, a low mountain range in western Germany, is one of Central Europe's largest eruptions over the past 100,000 years. The eruption ejected around 20 cubic kilometers of tephra and the eruption column is believed to have reached at least 20 kilometers in height, comparable to the Pinatubo eruption in the Philippines in 1991. Technical advances in combination with tree remains buried in the course of the eruption now enabled an international research team to accurately date the event. Accordingly, the eruption of the Laacher See volcano occurred 13,077 years ago and thus 126 years earlier than previously assumed. This sheds new light on the climate history of the entire North Atlantic and European region and requires an adaptation of the European climate archives. "We can now precisely date a drop in temperature at the end of the last glacial period, so that the information coincides with that observed from the Greenland Ice Sheet cores," said Dr. Frederick Reinig, a dendrochronologist at Johannes Gutenberg University in Mainz (JGU). An international research team with experts in archeology, climatology, ecology, radiocarbon dating, and volcanology was involved in this study. The research results were published in the renowned scientific journal Nature.

Charred remains of birch and poplar wood have been preserved to this day

The eruption of the Laacher See volcano was a natural disaster that affected large parts of Europe. The ash rain reached as far as northern Italy in the south and Saint Petersburg in the Northeast. In the immediate vicinity and the neighboring Rhine Valley, mighty deposits of ash and pumice formed, which buried all life beneath them. "During the eruption, pyroclastic flows buried the local vegetation around the Laacher See volcano. The trees were partially charred within the ash deposits and have been preserved to this day," explained Reinig, describing the eruption process that took place over several weeks in late spring to early summer and which now enables scientists to precisely date the event. "These wooden contemporary witnesses are very rare, and they are difficult to recover," said Reinig, first author of the study.

"The regional effects of the volcanic eruption have been well studied. What we have been missing so far is the certainty of when exactly this happened," emphasized Professor Ulf Büntgen, co-author of the Nature publication from the University of Cambridge. This was now determined based on samples from buried birch and poplar trees.

The analysis of tree rings reveals the precise date of the eruption

The volcanic sediments not only preserved the wood for over 13,000 years but also allowed to identify the individual tree rings. "The tree rings enable us to exactly determine the age of the samples," said Professor Jan Esper from Mainz University. In a joint initiative of the Federal Research Institute for Forests, Snow and Landscape WSL in Birmensdorf, Switzerland, together with the Archaeological Research Center and Museum for Human Behavioral Evolution MONREPOS in Neuwied, both newly discovered samples and older finds were analyzed. For this purpose, the Laboratory for Ion Beam Physics at ETH Zurich carried out radiocarbon measurements on 157 individual tree rings of the examined trees. Calibration of these results against a Swiss reference chronology then resulted in the precise dating. "The constant advances in radiocarbon measurement technology and the calibration methods used, as well as the careful handling of the sensitive samples, were the key to establish this dating with an uncertainty of less than ten years," said Lukas Wacker from ETH Zurich.

CAPTION

A charred tree trunk in the deposits of the Laacher See volcanic eruption: the individual annual rings of the sample were decisive for the exact dating of the eruption.

CREDIT

photo/©: Olaf Jöris

Revised dating of the volcanic eruption has consequences for the synchronization of European climate archives and the understanding of large-scale climate dynamics

According to the description in Nature, the eruption of the Laacher See volcano took place 13,006 years before 1950, with an uncertainty of nine years. That is 126 years earlier than the generally accepted dating based on sediments in the Meerfelder Maar from the Eifel region in Germany.

This difference has far-reaching consequences for the synchronization of European climate archives and the understanding of North Atlantic and European climate history. Laacher See eruption ashes were widespread over large areas of Central and Northern Europe as a result of the volcanic eruption and represent an important time marker for paleoenvironmental archives. Due to the new dating, the European archives now have to be temporally adapted. At the same time, a previously existing temporal difference to the data from the Greenland ice cores was closed.

This means that the massive cooling at the beginning of the Younger Dryas - i.e., the last Ice Age intermezzo lasting around 1,300 years before the currently prevailing warm phase, the Holocene - also occurred in Central Europe 130 years earlier, around 12,870 years ago respectively. This is in line with the onset of the cooling in the North Atlantic region identified in ice cores from Greenland. During the Younger Dryas period, temperatures in Central Europe fell by up to 5 degrees Celsius. This strong cooling did not take place time transgressively, as previously thought, but rather synchronously over the entire North Atlantic and Central European region," said Frederick Reinig. The results of the interdisciplinary research team not only set a precise date for the eruption of the Laacher See in the Eifel. The revised age of the ash deposits and the associated shift in the European climate archives now sheds new light on the climate history of the entire North Atlantic region.

CAPTION

Tree rings reveal much more than the age of a tree. For example, they allow conclusions to be drawn about the respective growing conditions and thus enable indirect climatic insight.

CREDIT

photo/©: Jan Esper

Images:

https://download.uni-mainz.de/presse/09_geograph_klimatologie_laacher_see_01.jpg
13,000 year old tree trunk from the volcanic deposits of the Laacher See eruption in the vicinity of Miesenheim, Germany. photo/©: Olaf Jöris

https://download.uni-mainz.de/presse/09_geograph_klimatologie_laacher_see_02.jpg
Recovery of a charred tree trunk that was buried by volcanic deposits during the Laacher See eruption. photo/©: Olaf Jöris

https://download.uni-mainz.de/presse/09_geograph_klimatologie_laacher_see_03.jpg
A charred tree trunk in the deposits of the Laacher See volcanic eruption: the individual annual rings of the sample were decisive for the exact dating of the eruption. photo/©: Olaf Jöris

https://download.uni-mainz.de/presse/09_geograph_klimatologie_laacher_see_04.jpg
The individual annual rings can be seen on an x-ray image of charred birch wood, recovered from the Laacher See Eruption deposits. photo/©: Frederick Reinig

https://download.uni-mainz.de/presse/09_geograph_klimatologie_laacher_see_05.jpg
Subfossil pine disc found in Zurich, Switzerland. Radiocarbon calibration of trees found within the Laacher See deposits against the Swiss radiocarbon reference based on such pines resulted in the precise eruption date. photo/©: Daniel Nievergelt

https://download.uni-mainz.de/presse/09_geograph_klimatologie_laacher_see_06.jpg
Tree rings reveal much more than the age of a tree. For example, they allow conclusions to be drawn about the respective growing conditions and thus enable indirect climatic insight. photo/©: Jan Esper

CAPTION

Portrait of Sir Patrick Geddes (c. 1888) at the age of 34, several years after publishing observations from his experiments on animals containing chlorophyll.

CREDIT

libraryblogs.is.ed.ac.uk

LaJeunesse and his colleagues used genetic information; outward physical, or morphological, characteristics; ecological traits; and geographic distributions to define the diversity found within the newly recognized Philozoon genus. They obtained animal samples -- including from soft and stony corals, jellyfish, and sea anemones -- from locations all over the world. They also obtained samples from Italy where Geddes first conducted his original research.

"Because our team comprises scientists from seven countries, we were able to collect all of these samples, and some during the global pandemic," said LaJeunesse. "This study highlights how the spirit of scientific discovery brings people together, even in times of hardship."

"The fact that these algae exist in animals from the Mediterranean Sea to New Zealand to Chile reminds us how widespread these symbioses are on Earth," said LaJeunesse. "Also, since most of the algae in the family Symbiodiniaceae have been thought to be mostly tropical where they are critical to the formation of coral reefs, finding and describing these new species in cold waters highlights the capacity of these symbioses to evolve and live under a broad range of environmental conditions. Life finds a way to persist and proliferate."

The team documented that at their northernmost and southernmost latitudinal extremes, Philozoon experience water temperatures that may reach winter lows of nearly 40 degrees F and summer highs of close to 90 F.

"The abilities of these Philozoons to withstand a wide range of temperatures is likely due to their diversification during the cooler periods of the late Pliocene and most recent Pleistocene epochs," said LaJeunesse. "This adaptation to a range of temperatures could protect them and the animals with which they associate from some of the effects of climate change, at least in the near term. Similarly, adaptation to high latitude environments may condition Philozoon species to tolerating future increases in atmospheric carbon dioxide, which could also help make them resilient to some of the effects of ocean acidification."

He added that careful identification and categorization of these symbiotic algae is essential to understanding the biology and evolution of marine animals that rely on these organisms for their survival.

"The advanced molecular-genetic techniques available to us today have substantially improved our ability to study and understand these microbes," said Pilar Casado-Amezúa, researcher, HyT Association, Spain. "Our new study lays the groundwork for extensive research on the ecological role of animal-algal mutualisms in temperate marine ecosystems."

LaJeunesse noted that although there were a handful of other scientists during the late 1800s that were investigating these 'yellow cells' it was Geddes who unequivocally recognized the full significance of the evidence before him.

He explained, "In describing the associations between the cells and the host animals, Geddes called them 'animal lichens' and eloquently wrote, 'Such an association is far more complex than that of the fungus and alga in the lichen, and indeed stands unique in the physiology as the highest development, not of parasitism, but of the reciprocity between the animal and vegetable kingdoms.' Geddes vigorously contended that these algae were symbiotic in nature. Now, more than a century after their discovery, the true identities of these algae are finally being properly characterized."

CAPTION

The jellyfish, Cotylorhiza tuberculata, from Naples, Italy hosts the symbiotic algae Philozoon medusarum.

CREDIT

Marco Cannavacciuolo

Other authors on the paper include Joerg Wiedenmann, University of Southampton, United Kingdom; Pilar Casado-Amezúa, Hombre y Territorio Association, Spain; Isabella D'Ambra, Stazione Zoologica Anton Dohrn, Italy; Kira Turnham, Penn State, United States; Matthew Nitschke, University of Technology Sydney, Australia, and Victoria University of Wellington, New Zealand; Clinton Oakley, Victoria University of Wellington, New Zealand; Stefano Goffredo, University of Bologna, Spain, and The Inter-Institute Center for Research on Marine Biodiversity, Resources and Biotechnologies, Italy; Carlos Spano, Ecotecnos S.A., Chile; Victor Cubillos, Universidad Austral de Chile, Chile, and Universidad Austral de Chile, Chile; Simon Davy, Victoria University of Wellington, New Zealand; and David Suggett, University of Technology Sydney, Australia.

Funding for this research was provided by the U.S. National Science Foundation, the University of Southampton, the Association of Marine Biology Laboratories Program, the ABBaCo project, PO FEAMP Campania and the Australian Research Council.

Near-death experiences, a survival strategy ?

A study in the journal Brain Communications by Danish and Belgian researchers attributes for the first time a biological purpose to near-death experiences (NDEs)

UNIVERSITY OF LIEGE

Research News

Near-death experiences are known from all parts of the world, various times and numerous cultural backgrounds. This universality suggests they may have a biological origin and purpose, but exactly what this could be has been largely unexplored.

A new study conducted jointly by the University of Copenhagen (Denmark) and the University of Liege (Belgium) and published in Brain Communications shows how near-death experiences in humans may have arisen from evolutionary mechanisms.

"Adhering to a preregistered protocol, we investigated the hypothesis that thanatosis is the evolutionary origin of near-death experiences", says Daniel Kondziella, a neurologist from Rigshospitalet, Copenhagen University Hospital.

When attacked by a predator, as a last resort defense mechanism, animals can feign death to improve their chances of survival, one example being the opossum. This phenomenon is termed thanatosis, also known as death-feigning or tonic immobility. "As a survival strategy," Daniel Kondziella adds, "thanatosis is probably as old as the fight-or-flight response."

Charlotte Martial, neuropsychologist from the Coma Science Group at ULiège explains: "We first show that thanatosis is a highly preserved survival strategy occurring at all major nodes in a cladogram ranging from insects to fish, reptiles, birds and mammals, including humans. We then show that humans under attack by big animals such as lions or grizzly bears, human predators such as sexual offenders, and 'modern' predators such as cars in traffic accidents can experience both thanatosis and near-death experiences. Furthermore, we show that the phenomenology and the effects of thanatosis and near-death experiences overlap."

Steven Laureys, neurologist and head of GIGA Consciousness research unit and Centre du Cerveau (ULiège, CHU Liège) is excited: "In this paper, we build a line of evidence suggesting that thanatosis is the evolutionary foundation of near-death experiences and that their shared biological purpose is the benefit of survival."

The authors propose that the acquisition of language enabled humans to transform these events from relatively stereotyped death-feigning under predatory attacks into the rich perceptions that form near-death experiences and extend to non-predatory situations.

"Of note, the proposed cerebral mechanisms behind death-feigning are not unlike those that have been suggested to induce near-death experiences, including intrusion of rapid eye movement sleep into wakefulness," Daniel Kondziella explains. "This further strengthens the idea that evolutionary mechanisms are an important piece of information needed to develop a complete biological framework for near-death experiences."

No previous work has tried to provide such a phylogenetic basis. Steven Laureys concludes, "this may also be the first time we can assign a biological purpose to near-death experiences, which would be the benefit of survival."

And Daniel Kondziella adds, "after all, near-death experiences are by definition events that are always survived, without exception."

THE METHOD OF SCIENCE THE AIM OF RELIGION

Researchers identify brain circuit for spirituality

Using datasets from neurosurgical patients and those with brain lesions, investigators mapped lesion locations associated with spiritual and religious belief to a specific human brain circuit

BRIGHAM AND WOMEN'S HOSPITAL

Research News

More than 80 percent of people around the world consider themselves to be religious or spiritual. But research on the neuroscience of spirituality and religiosity has been sparse. Previous studies have used functional neuroimaging, in which an individual undergoes a brain scan while performing a task to see what areas of the brain light up. But these correlative studies have given a spotty and often inconsistent picture of spirituality. A new study led by investigators at Brigham and Women's Hospital takes a new approach to mapping spirituality and religiosity and finds that spiritual acceptance can be localized to a specific brain circuit. This brain circuit is centered in the periaqueductal gray (PAG), a brainstem region that has been implicated in numerous functions, including fear conditioning, pain modulation, altruistic behaviors and unconditional love. The team's findings are published in Biological Psychiatry.

"Our results suggest that spirituality and religiosity are rooted in fundamental, neurobiological dynamics and deeply woven into our neuro-fabric," said corresponding author Michael Ferguson, PhD, a principal investigator in the Brigham's Center for Brain Circuit Therapeutics. "We were astonished to find that this brain circuit for spirituality is centered in one of the most evolutionarily preserved structures in the brain."

To conduct their study, Ferguson and colleagues used a technique called lesion network mapping that allows investigators to map complex human behaviors to specific brain circuits based on the locations of brain lesions in patients. The team leveraged a previously published dataset that included 88 neurosurgical patients who were undergoing surgery to remove a brain tumor. Lesion locations were distributed throughout the brain. Patients completed a survey that included questions about spiritual acceptance before and after surgery. The team validated their results using a second dataset made up of more than 100 patients with lesions caused by penetrating head trauma from combat during the Vietnam War. These participants also completed questionnaires that included questions about religiosity (such as, "Do you consider yourself a religious person? Yes or No?").

Of the 88 neurosurgical patients, 30 showed a decrease in self-reported spiritual belief before and after neurosurgical brain tumor resection, 29 showed an increase, and 29 showed no change. Using lesion network mapping, the team found that self-reported spirituality mapped to a specific brain circuit centered on the PAG. The circuit included positive nodes and negative nodes -- lesions that disrupted these respective nodes either decreased or increased self-reported spiritual beliefs. Results on religiosity from the second dataset aligned with these findings. In addition, in a review of the literature, the researchers found several case reports of patients who became hyper-religious after experiencing brain lesions that affected the negative nodes of the circuit.

Lesion locations associated with other neurological and psychiatric symptoms also intersected with the spirituality circuit. Specifically, lesions causing parkinsonism intersected positive areas of the circuit, as did lesions associated with decreased spirituality. Lesions causing delusions and alien limb syndrome intersected with negative regions, associated with increased spirituality and religiosity.

"It's important to note that these overlaps may be helpful for understanding shared features and associations, but these results should not be over-interpreted," said Ferguson. "For example, our results do not imply that religion is a delusion, that historical religious figures suffered from alien limb syndrome, or that Parkinson's disease arises due to a lack of religious faith. Instead, our results point to the deep roots of spiritual beliefs in a part of our brain that's been implicated in many important functions."

The authors note that the datasets they used do not provide rich information about the patient's upbringing, which can have an influence over spiritual beliefs, and that patients in both datasets were from predominantly Christian cultures. To understand the generalizability of their results, they would need to replicate their study across many backgrounds. The team is also interested in untangling religiosity and spirituality to understand brain circuits that may be driving differences. Additionally, Ferguson would like to pursue clinical and translational applications for the findings, including understanding the role that spirituality and compassion may have in clinical treatment.

"Only recently have medicine and spirituality been fractionated from one another. There seems to be this perennial union between healing and spirituality across cultures and civilizations," said Ferguson. "I'm interested in the degree to which our understanding of brain circuits could help craft scientifically grounded, clinically-translatable questions about how healing and spirituality can co-inform each other."

###

Funding for this work was provided by an NIH Ruth L. Kirschstein National Research Service Award (NRSA) Institutional Research Training Grant (T32MH112510), the Shields Research Grant from the Child Neurology Foundation, the Sidney R. Baer, Jr. Foundation, the Nancy Lurie Marks Foundation, the Mather's Foundation, the Kaye Family Research Endowment, and the National Institutes of Health (grants R01 MH113929, R01 MH115949, and R01 AG060987).

Paper cited: Ferguson, M et al. "neural circuit for spirituality and religiosity derived from patients with brain lesions" Biological Psychiatry DOI: 10.1016/j.biopsych.2021.06.016

LA REVUE GAUCHE - Left Comment

Friday, July 02, 2021

The rise and fall of elephants

RUDN University chemists synthesize biodiesel from jatropha curcas plant

Catalyzing the conversion of biomass to biofuel

CAPTION

CREDIT

CAPTION

CREDIT

CAPTION

CREDIT

CAPTION

CREDIT

Near-death experiences, a survival strategy ?

About Me