Tag Archives: #primates

Travel Paths of Primates Show How Their Minds Work (Neuroscience)

How primates get from A to B gives vital information about their cognitive evolution, say researchers in a new study looking at the travel paths of animals in the wild. Using data from 164 wild primate populations, the global survey examines the mental abilities that primates, including ourselves, use to know where and when to travel in the most efficient way.

A birds eye view

Co-author Miguel de Guinea, expert in Evolutionary Anthropology at Oxford Brookes University commented: “Imagine looking down on a huge outdoor market from high in the sky, perhaps from a drone hovering quietly above. The people below move in different ways. Some wander haphazardly among the stalls: they are learning what’s available but are clearly not busy. Others take bee-line routes across the market to a destination they obviously wanted to reach, then, after buying what they need, head back in much the same way.

“If you could distinguish individuals, and watch them on many occasions, these patterns are likely to change, sometimes dependent on fruit and vegetables in season. We would also begin to learn about social aspects, as networks of repeated contacts show who is friendly with whom. We can get a good idea of people’s knowledge, their needs, their ability to think ahead and how they learn over time –  just from watching their travel paths. The same observations have been made by the research team using data from GPS devices and in-field studies of wild primates, giving us fascinating information about their development.”

Travel decision-making adds to picture

The original data was gathered from small GPS devices, used routinely in primate fieldwork: sometimes these are attached to the animals themselves, but in many studies a researcher follows the animals, usually noting a rich variety of background information on what they are doing and for how long.

The international team developed a conceptual framework to highlight ways in which these data can be analysed. Currently, primate cognition is studied by comparing measures such as brain size, or conducting experiments with artificial problems to primates in captivity. The evidence from travel decision-making amongst wild populations will enhance these approaches and give a fuller picture of the cognitive development of these species.

An urgent vision for primate research

Lead-author Karline Janmaat from the University of Amsterdam said: “Our ultimate dream is to set up a consortium to support data sharing and collaboration among primatologists. Hopefully this attracts MSc and PhD students from around the world to share and compare their collected data to these existing datasets.” 

The researchers say that further research is urgent, because so many species are now threatened with extinction in the wild.  Since 1970, two-thirds of all vertebrate populations have been lost, and large, day-living animals like primates have been significantly impacted. 

Miguel de Guinea stressed: “Time is fast running out – if we don’t act now we may never be able to understand the drivers of cognitive evolution. By applying our research methodology and findings we can make use of previously collected valuable data from wild populations and apply that to our understanding of the cognitive evolution of primate species.”

The research Using natural travel paths to infer and compare primate cognition in the wild is published in iScience.

Provided by Oxford Brookes University

One of Africa’s Rarest Primates Protected by… Speedbumps (Biology)

New research quantifies the numbers of endangered Zanzibar red colobus monkey killed by collisions with vehicles and the benefit of installing speedbumps near protected forest areas

A new study revealed that a drastic reduction of deaths of one of Africa’s rarest primates, the Zanzibar red colobus (Piliocolobus kirkii), followed the installation of four speedbumps along a stretch of road where the species frequently crossed.

Zanzibar red colobus are found only in the Zanzibar archipelago and classified as Endangered by the IUCN Red List. Reliant on Unguja Island’s forests for their survival, around half of the species population is found in Jozani-Chwaka Bay National Park.

In the study, published in Oryx – The International Journal of Conservation, primatologists from Bangor University, in collaboration with national park managers from Zanzibar and the Wildlife Conservation Society (WCS), assessed mortality from vehicle collisions – a growing threat faced by primates living in increasingly fragmented habitats crisscrossed by roads.

They found that historic data from the road traversing the national park showed that one colobus was killed on average every 2-3 weeks by traffic. After speedbumps were installed, this was reduced to one every six weeks.

While great progress, this mortality rate is still a significant threat to the species – especially given that natural predation tends to target weaker individuals, yet roadkill is indiscriminate, killing reproductively active adults as well as the very young and old.

Bangor primatologist and Director of the Zanzibar Red Colobus Project, Dr. Alexander Georgiev, and senior author of this study, said: “Cars are not selective in the animals they kill. This means that while natural predators may target the very young and old more often, cars are equally likely to kill reproductively active young adults, who would contribute the most to population growth. And this may be a problem.”

Harry Olgun, now a PhD student at the University’s School of Natural Sciences, led this study as part of his Masters research on the road ecology of the Zanzibar red colobus. Olgun said: “After the road at Jozani was surfaced but before the speedbumps were installed, a colobus was reported to have been killed every two to three weeks, resulting in perhaps about 12-17 percent annual mortality, according to one estimate. The recent data show that speedbumps have made a huge difference for the safety of the colobus. Adding more speedbumps would help reduce the risk further.”

Dr. Tim Davenport, Director of Species Conservation & Science in Africa at WCS, who led the first countrywide census of the Zanzibar red colobus a few years ago and is a coauthor of the study, said: “As tourism grows in Zanzibar and habitat continues to shrink, using science to quantify and solve conservation problems has never been so important. Understanding the impact of vehicles on wildlife within a park, and implementing practical solutions is exactly what we as conservationists should be doing.”

Featured image credit: Tim R. B. Davenport

Reference: Olgun, H., Mohammed, M., Mzee, A., Green, M., Davenport, T., & Georgiev, A. (2021). The implications of vehicle collisions for the Endangered endemic Zanzibar red colobus Piliocolobus kirkii. Oryx, 1-9. doi: 10.1017/S0030605320000605

Provided by Wildlife Conservation Society

Scientists Describe Earliest Primate Fossils (Paleontology)

A new study published Feb. 24 in the journal Royal Society Open Science documents the earliest-known fossil evidence of primates.

A team of 10 researchers from across the U.S. analyzed several fossils of Purgatorius, the oldest genus in a group of the earliest-known primates called plesiadapiforms. These ancient mammals were small-bodied and ate specialized diets of insects and fruits that varied by species. These newly described specimens are central to understanding primate ancestry and paint a picture of how life on land recovered after the Cretaceous-Paleogene extinction event 66 million years ago that wiped out all dinosaurs — except for birds — and led to the rise of mammals.

Gregory Wilson Mantilla, a University of Washington professor of biology and curator of vertebrate paleontology at the UW’s Burke Museum of Natural History & Culture, co-led the study with Stephen Chester of Brooklyn College and the City University of New York. The team analyzed fossilized teeth found in the Hell Creek area of northeastern Montana. The fossils, which are now part of the collections at the University of California Museum of Paleontology, are estimated to be 65.9 million years old, about 105,000 to 139,000 years after the mass extinction event. Based on the age of the fossils, the team estimates that the ancestor of all primates —including plesiadapiforms and today’s primates such as lemurs, monkeys and apes — likely emerged by the Late Cretaceous and lived alongside large dinosaurs.

“It’s mind blowing to think of our earliest archaic primate ancestors,” said Wilson Mantilla. “They were some of the first mammals to diversify in this new post-mass extinction world, taking advantage of the fruits and insects up in the forest canopy.”

The fossils include two species of PurgatoriusPurgatorius janisae and a new species described by the team named Purgatorius mckeeveri. Three of the teeth found have distinct features compared to any previously known Purgatorius species and led to the description of the new species.

High resolution CT scans of an assortment of fossilized teeth and jaw bones of Purgatorius.Gregory Wilson Mantilla/Stephen Chester

Purgatorius mckeeveri is named after Frank McKeever, who was among the first residents of the area where the fossils were discovered, and also the family of John and Cathy McKeever, who have since supported the field work where the oldest specimen of this new species was discovered.

“This was a really cool study to be a part of, particularly because it provides further evidence that the earliest primates originated before the extinction of non-avian dinosaurs,” said co-author Brody Hovatter, a UW graduate student in Earth and space sciences. “They became highly abundant within a million years after that extinction.”

“This discovery is exciting because it represents the oldest dated occurrence of archaic primates in the fossil record,” said Chester. “It adds to our understanding of how the earliest primates separated themselves from their competitors following the demise of the dinosaurs.”

Co-author on the study was the late William Clemens who was a professor emeritus at the University of California, Berkeley and former director of the UC Museum of Paleontology. Additional co-authors are Jason Moore and Wade Mans of the University of New Mexico; Courtney Sprain of the University of Florida; William Mitchell of Minnesota IT Services; Roland Mundil of the Berkeley Geochronology Center; and Paul Renne of UC Berkeley and the Berkeley Geochronology Center. The research was funded by the National Science Foundation, the UC Museum of Paleontology, the Myhrvold and Havranek Charitable Family Fund, the UW, the CUNY and the Leakey Foundation.

Featured image: Shortly after the extinction of the dinosaurs, the earliest known archaic primates, such as the newly described species Purgatorius mckeeveri shown in the foreground, quickly set themselves apart from their competition — like the archaic ungulate mammal on the forest floor — by specializing in an omnivorous diet including fruit found up in the trees. © Andrey Atuchin

Reference: Gregory P. Wilson Mantilla, Stephen G. B. Chester, “Earliest Palaeocene purgatoriids and the initial radiation of stem primates”, ROYAL Society Publishing B, 2021. https://royalsocietypublishing.org/doi/10.1098/rsos.210050

Provided by University of Washington

Stimulating Brain Pathways Shows Origins of Human Language and Memory (Neuroscience)

Scientists have identified that the evolutionary development of human and primate brains may have been similar for communication and memory.

Although speech and language are unique to humans, experts have found that the brain’s pathway is similarly wired in monkeys which could signify an evolutionary process dating back at least 25 million years.

In a study, published in the journal Neuron, teams led by Newcastle University and the University of Iowa, compared auditory cortex information from humans and primates and found strong links.

Professor Chris Petkov, from Newcastle University’s Faculty of Medical Sciences, said: “Our language abilities help us to crystallise memories and make them vivid, such as ‘the singer sounded like a nightingale’.

“Therefore, it’s often thought that the human language and memory brain systems went through a substantial transformation during our recent evolutionary history, distinguishing us from every other living animal.

“We were astounded to see such striking similarity with other primates, and this discovery has substantial importance for science and neurological disorders.”

This discovery has substantial importance for science and neurological disorder. 

— Professor Chris Petkov

Stimulating auditory cortex

Scientists used information from neurosurgery patients being monitored for treatment. With humans, stimulation of a specific part of the brain can be visualized if brain imaging is used at the same time.

The experts also compared the results from stimulating auditory cortex and visualising areas important for language and memory in monkeys.

The brain stimulation highlighted a previously unseen ancestral brain highway system that is deeply shared by humans and monkeys, one that is likely to have been present in ancestral primates to both species.

The finding is important because brain stimulation is a common treatment for neurological and psychiatric disorders. However, how brain stimulation works is not well understood and requires work that cannot be conducted with humans. Work with non-human primates has paved the way for current brain treatments, including Parkinson’s disease.

Inspiring new research

The study has generated unique new brain scanning information that can now be globally shared to inspire further discovery by the international scientific community.

Professor Matthew Howard III, chief neurosurgeon at the University of Iowa Carver Medical Center, USA, co-author of the study, said: “This discovery has tremendous potential for understanding how brain stimulation could help patients, which requires studies with animal models not possible to conduct with humans.”

Professor Tim Griffiths, consultant neurologist at Newcastle University, also co-author of the study, added: “This discovery has already inspired new research underway with neurology and neurosurgery patients.”


Common fronto-temporal effective connectivity in humans and monkeys. Francesca Rocchi et al. Neuron. DOI: 10.1016/j.neuron.2020.12.026

Provided by Newcastle University

Biodistribution of AAV Gene Transfer Vectors in Nonhuman Primate (Medicine)

The biodistribution of adeno-associated virus (AAV) gene transfer vectors can be measured in nonhuman primates using a new method. The method quantifies whole-body and organ-specific AAV capsids from 1 to 72 hours after administration. Study design and results are presented in the peer-reviewed journal Human Gene TherapyClick here to read the full-text article free on the Human Gene Therapy website through February 15, 2021.

Provides all-inclusive access to the critical pillars of human gene therapy: research, methods, and clinical applications. Mary Ann Liebert, Inc., publishers

AAV capsids were labeled with I-124 and delivered using two routes of administration: intravenous and directly into the cerebrospinal fluid (CSF). Biodistribution was measured by quantitative positron emission tomography (PET) at 1, 24, 48, and 72 hours after AAV administration. Two AAV vectors – AAVrsh.10 and AAV9 – were compared.

“Following intravenous administration, both vectors behaved in a similar fashion, distributed primarily to the liver and to a lesser extent heart. Neither were detected at significant levels in the brain. Both vectors administered intravenously also distribute to the vertebrae,” state Ronald Crystal, Weill Cornell Medical College, and coauthors. About 50% dispersed throughout the body, in part in skeletal muscle.

Following administration into the CSF, the labeled capsid had a half-life of approximately 10 hours, suggesting the possibility of slow diffusion into the brain.

In animals with pre-existing immunity, compared to naïve animals, there was a 10-fold increase in biodistribution to the spleen.

“PET imaging is a powerful tool to track biodistribution, which is a critical property affecting the safety and efficacy of gene therapy,” according to Editor-in-Chief of Human Gene Therapy Terence R. Flotte, MD, Celia and Isaac Haidak Professor of Medical Education and Dean, Provost, and Executive Deputy Chancellor, University of Massachusetts Medical School.

Research reported in this publication was supported by the National Institutes of Health under Award Number EB027918. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Reference: Douglas J. Ballon, Jonathan B. Rosenberg et al., “Quantitative Whole-Body Imaging of I-124-Labeled Adeno-Associated Viral Vector Biodistribution in Nonhuman Primates”, Human Gene Therapy, Vol. 31, No. 23-24, 2021. https://www.liebertpub.com/doi/10.1089/hum.2020.116 https://doi.org/10.1089/hum.2020.116

Provided by Mary Ann Liebert

About the Journal

Human Gene Therapy, the Official Journal of the European Society of Gene and Cell Therapy and eight other international gene therapy societies, was the first peer-reviewed journal in the field and provides all-inclusive access to the critical pillars of human gene therapy: research, methods, and clinical applications. The Journal is led by Editor-in-Chief Terence R. Flotte, MD, Celia and Isaac Haidak Professor of Medical Education and Dean, Provost, and Executive Deputy Chancellor, University of Massachusetts Medical School, and an esteemed international editorial board. Human Gene Therapy is available in print and online. Complete tables of contents and a sample issue are available on the Human Gene Therapy website.

About the Publisher

Mary Ann Liebert, Inc., publishers is known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research. Its biotechnology trade magazine, GEN (Genetic Engineering & Biotechnology News), was the first in its field and is today the industry’s most widely read publication worldwide. A complete list of the firm’s 90 journals, books, and newsmagazines is available on the  Mary Ann Liebert, Inc., publishers website.

Fingerprints Moisture-regulating Mechanism Strengthens Human Touch (Biology)

Human fingerprints have a self-regulating moisture mechanism that not only helps us to avoid dropping our smartphone, but could help scientists to develop better prosthetic limbs, robotic equipment and virtual reality environments, a new study reveals.

Fingerprints’ moisture mechanism could be boon to robotics experts © University of Birmingham

Primates – including humans, monkeys and apes – have evolved epidermal ridges on their hands and feet with a higher density of sweat glands than elsewhere on their bodies. This allows precise regulation of skin moisture to give greater levels of grip when manipulating objects.

Fingerprints help to increase friction when in contact with smooth surfaces, boost grip on rough surfaces and enhance tactile sensitivity. Their moisture-regulating mechanism ensures the best possible hydration of the skin’s keratin layer to maximise friction.

Researchers at the University of Birmingham worked with partners at research institutions in South Korea, including Seoul National University and Yonsei University – publishing their findings today in Proceedings of the National Academy of Sciences (PNAS).

Co-author Mike Adams, Professor in Product Engineering and Manufacturing, at the University of Birmingham commented: “Primates have evolved epidermal ridges on their hands and feet. During contact with solid objects, fingerprint ridges are important for grip and precision manipulation. They regulate moisture levels from external sources or the sweat pores so that friction is maximised and we avoid ‘catastrophic’ slip and keep hold of that smartphone.”

“Understanding the influence of finger pad friction will help us to develop more realistic tactile sensors – for example, applications in robotics and prosthetics and haptic feedback systems for touch screens and virtual reality environments.”

Ultrasonic lubrication is commonly used in touch screen displays that provide sensory ‘haptic’ feedback, but its effectiveness is reduced when a user has dry compared with moist finger pads. Moreover, being able to distinguish between fine-textured surfaces, such as textiles, by touch relies on the induced lateral vibrations but the absence of sliding friction inhibits our ability to identify what we are actually touching.

Fingerprints are unique to primates and koalas – appearing to have the dual function of enhancing evaporation of excess moisture whist providing a reservoir of moisture at their bases that enables grip to be maximised.

The researchers have discovered that, when finger pads are in contact with impermeable surfaces, the sweat from pores in the ridges makes the skin softer and thus dramatically increases friction. However, the resulting increase in the compliance of the ridges causes the sweat pores eventually to become blocked and hence prevents excessive moisture that would reduce our ability to grip objects.

Using hi-tech laser-based imaging technology, the scientists found that moisture regulation could be explained by the combination of this sweat pore blocking and the accelerated evaporation of excessive moisture from external wetting as a result of the specific cross-sectional shape of the epidermal furrows when in contact with an object.

These two functions result in maintaining the optimum amount of moisture in the fingerprint ridges that maximises friction whether the finger pad is initially wet or dry.

“This dual-mechanism for managing moisture has provided primates with an evolutionary advantage in dry and wet conditions – giving them manipulative and locomotive abilities not available to other animals, such as bears and big cats,” added Professor Adams.

Reference: Seoung-Mok Yum, In-Keun Baek, Dongpyo Hong, Juhan Kim, Kyunghoon Jung, Seontae Kim, Kihoon Eom, Jeongmin Jang, Seonmyeong Kim, Matlabjon Sattorov, Min-Geol Lee, Sungwan Kim, Michael J. Adams, Gun-Sik Park, “Fingerprint ridges allow primates to regulate grip”, Proceedings of the National Academy of Sciences Nov 2020, 202001055; DOI: 10.1073/pnas.2001055117 https://www.pnas.org/content/early/2020/11/24/2001055117

Provided by University of Birmingham

Notes to editors:

* The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 6,500 international students from over 150 countries.
* ‘Fingerprint ridges allow primates to regulate grip’ – Seoung-Mok Yum, In-Keun Baek, Dongpyo Hong, Juhan Kim, Kyunghoon Jung, Seontae Kim, Kihoon Eom, Jeongmin Jang, Seonmyeong Kim, Matlabjon Sattorov, Min-Geol Leed, Sungwan Kime, Michael J. Adams and Gun-Sik Parka is published in Proceedings of the National Academy of Sciences (PNAS)

A Modified Game Of ‘Chicken’ Reveals What Happens in the Brain During Decision-making (Neuroscience)

Better understanding what happens in the brain when people cooperate and make social decisions has the potential to help boost such behaviors. It’s been a research focus for the University of Pennsylvania’s Platt Labs for some time.


“The social brain network contains a number of different areas critical to managing interactions and connecting with others,” says Penn Integrates Knowledge Professor Michael Platt. “One is more emotional, critical for empathy and learning from others. That’s the anterior cingulate gyrus. The other is more cognitive, and for humans that lives in the temporoparietal junction.”

In nonhuman primates, the anterior cingulate gyrus mirrors what it does in humans, responding to rewards and pain, both for themselves and others. Until recently, scientists believed that nonhuman primates did not have an equivalent to the temporoparietal junction, which activates when humans think about the beliefs, desires, and goals of others. But new research on rhesus macaques from Platt, postdoctoral fellow Wei Song Ong, and Duke University postdoctoral fellow Seth Madlon-Kay confirms that an area called the middle superior temporal sulcus (mSTS) actually plays a similar role.

What’s more, analyzing the firing rates of neurons in those two sections of the brain as the macaques engage in a task together—one in which the reward for each participant depends, in part, on how the two cooperate—reveals a high level of strategic decision-making, findings Platt and colleagues published in the journal Nature Neuroscience.

To test the research team’s theories about the role of these brain regions, Ong created an experiment akin to a modified game of chicken. In the best-known version, participants face off and move toward each other in actual cars; the one who swerves to avoid the collision is the chicken. “Here, each monkey uses a joystick to control a circle or ring, which we call a car,” Platt says. “They have about 10 seconds to decide whether to drive the car straight or turn it to the side.”

In either direction, the macaques see tokens proportional to the juice reward they would receive for driving to each spot. “The temptation is to drive forward because there is typically more reward there,” he says. “But if they both drive forward, they ‘crash,” and no one gets a reward.” The researchers also placed a white bar behind the side tokens; if the participants coordinated their behavior, turning to that spot at the same time, they could unlock the extra reward.

“It’s a way to give them the opportunity to work together,” Platt says. “It’s never more reward than going forward, but it’s an intermediate. It’s better than losing.”

With the study design set, the Penn team conducted tens of thousands of trials for three conditions: one with two active participants, a second with an active participant and a computer, and third with an active participant and a decoy participant that sat in the opposite seat and shared the rewards but never actually controlled the joystick.

The researchers observed the behavior in each trial to determine, first and foremost, whether the macaques understood the rules. “The initial pass at the data shows they do,” says Platt. “They follow the payoffs. They’re more or less performing optimally.” The researchers then built a computational model of the behavior, progressively adding in components—previous actions, number of tokens available, actions of the partner participant—to explain what was happening. Finally, they used the parameters from the model as variables in trying to understand what information the neurons in each area were encoding.

Taking this all into account, they discovered that for nonhuman primates the anterior cingulate gyrus and mSTS behave similarly to the anterior cingulate gyrus and the temporoparietal junction in humans, specifically as they relate to coordination and high-level decision-making.

“This is a really interesting outcome,” Platt says. “It tells us a lot about how sophisticated monkeys are in terms of their social reasoning. It tells us something about the process unfolding in the brain as we interact with another individual and make decisions for or against each other. And it tells us that our ability to cooperate, to work together in societies, emerged from ancestral adaptations that evolved some 20 million years ago.”

In the future, Platt says he would like to test the findings on more realistic tasks and situations, to determine whether they hold up in real-world scenarios.

For now, the latest research brings the team nearer to comprehending what happens in the brain during humans’ decision-making process. “We are closer to understanding, in a general sense, how this system works,” he says, “how differences in the way this system functions in different people might be associated with different types of social decisions.”

References: Ong, W.S., Madlon-Kay, S. & Platt, M.L. Neuronal correlates of strategic cooperation in monkeys. Nat Neurosci (2020). https://www.nature.com/articles/s41593-020-00746-9 https://doi.org/10.1038/s41593-020-00746-9

Provided by University of Pennsylvania

About University of Pennsylvania

The University of Pennsylvania (Penn) was founded in 1740 by Benjamin Franklin and is the oldest private university in the United States. Today, Penn has nearly 20,000 undergraduate and graduate students. Ben Franklin was influenced by the European model for a multi-discipline approach in higher education. Penn is noted for the Wharton School of Business, Annenberg School for Communication, School of Medicine, School of Veterinary Medicine, School of Design and School of Engineering and Applied Science. Penn is ranked alongside Cal Tech for its selective admissions and quality of undergraduate students.

New Primate Species Discovered In Myanmar (Biology)

A new primate species dubbed the Popa langur has been discovered in Myanmar after years of extensive study, including analysis of a 100-year old specimen kept in the London Natural History Museum. The Popa langur (Trachypithecus popa) is described in a new scientific paper released today that documents the extensive genetic and morphological studies and field surveys undertaken by the German Primate Center (DPZ) – Leibniz Institute for Primate Research in Göttingen and conservation NGO Fauna & Flora International.

Adult female and juvenile Popa langur (Trachypithecus popa) in the crater of Mount Popa, Myanmar. Photo: Thaung Win

The Popa langur only occurs in central Myanmar and is named after the sacred Mount Popa, which holds the largest population of the species with about 100 animals. Mount Popa is an extinct volcano, which features an important wildlife sanctuary, as well as a sacred pilgrimage site, home to Myanmar’s most venerated spirits, known as ‘Nats’. Altogether there are only 200 to 250 animals of the new species, which live in four isolated populations. Throughout its range the langur is threatened by habitat loss and hunting, and the new species can be considered critically endangered. “Just described, the Popa langur is already facing extinction,” says Frank Momberg at FFI.

Researchers of the DPZ and FFI in collaboration with partners from other non-government organizations, universities and natural history museums, investigated the evolutionary history and species diversity of langurs in Myanmar. Their study resulted in the description of the new langur species, the Popa langur.

Stuffed holotype (NHMUK ZD.1914.7.19.3) of the newly described Popa langur (Trachypithecus popa) in the Natural History Museum, London, UK. Photo: Courtesy of the Trustees of the Natural History Museum, London

The Popa langur differs from known species in fur coloration, tail length and skull measurements. Genetic studies revealed that the new langur species separated from known species around one million years ago. The DNA for genetic analyses was obtained from fecal samples collected by FFI staff in the wild, as well as from tissue samples of historical specimens from the natural history museums in London, Leiden, New York and Singapore.

Christian Roos, scientist in the Primate Genetics Laboratory at DPZ says, ”The DNA analysis of a museum specimen collected for the London Natural History Museum more than 100 years ago has finally led to the description of this new species, confirmed also by samples collected from the field by FFI’s research team.” “Additional field surveys and protection measures are urgently required and will be conducted by FFI and others to save the langurs from extinction,” says Ngwe Lwin, a primatologist with FFI’s Myanmar program.

References: Christian Roos, Kristofer M. Helgen, Roberto Portela Miguez, Naw May Lay Thant, Ngwe Lwin, Aung Ko Lin, Aung Lin, Khin Mar Yi, Paing Soe, Zin Mar Hein, Margaret Nyein Nyein Myint, Tanvir Ahmed, Dilip Chetry, Melina Urh, E. Grace Veatch, Neil Duncan, Pepijn Kamminga, Marcus A. H. Chua, Lu Yao, Christian Matauschek, Dirk Meyer, Zhijin Liu, Ming Li, Tilo Nadler, Pengfei Fan, Le Khac Quyet, Michael Hofreiter, Dietmar Zinner, Frank Momberg (2020): Mitogenomic phylogeny of the Asian colobine genus Trachypithecus with special focus on Trachypithecus phayrei (Blyth, 1847) and description of a new species. Zoological Research, http://www.zoores.ac.cn/en/article/doi/10.24272/j.issn.2095-8137.2020.254

Provided by DPZ

Primates Aren’t Quite Frogs (Neuroscience)

Spinal modules in macaques can independently control forelimb force direction and magnitude.

Researchers in Japan demonstrated for the first time the ‘spinal motor module hypothesis’ in the primate arm, opening a new pathway for recovery after disease or injury.

An experiment nearly 40 years ago in frogs showed that their leg muscles were controlled by simultaneously recruitment of two modules of neurons. It’s a bit more complex in macaques (The National Center of Neurology and Psychiatry).

The human hand has 27 muscles and 18 joints, which our nervous system is able to coordinate for complex movements. However, the number of combinations — or degrees of freedom — is so large that attempting to artificially replicate this control and adjustment of muscle activity in real time taxes even a modern supercomputer. While the method used by the central nervous system to reduce this complexity is still being intensely studied, the “motor module” hypothesis is one possibility.

Under the motor module hypothesis, the brain recruits interneuronal modules in the spinal cord rather than individual muscles to create movement; wherein different modules can be combined to create specific movements. Nearly 40 years ago, research in frogs showed that simultaneously recruiting two modules of neurons controlling leg muscles created the same pattern of motor activity that represents a “linear summation” of the two component patterns.

An international team of researchers, led by Kazuhiko Seki at the National Center of Neurology and Psychiatry’s Department of Neurophysiology, in collaboration with David Kowalski of Drexel University and Tomohiko Takei of Kyoto University’s Hakubi Center for Advanced Research, attempted to determine if this motor control method is also present in the primate spinal cord. If validated, it would provide new insight into the importance of spinal interneurons in motor activity and lead to new ideas in movement disorder treatments and perhaps even a method to “reanimate” a limb post-spinal injury.

The team implanted a small array of electrodes into the cervical spinal cord in three macaques. Under anesthesia, different groups of interneurons were recruited individually using a technique called intraspinal microstimulation, or ISMS. The team found that, as in the frog leg, the force direction of the arm at the wrist during dual-site simulation was equal to the linear summation of the individually recruited outputs. However, unlike the frog leg, the force magnitude output could be many times higher than that expected from a simple linear summation of the individual outputs. When the team examined the muscle activity, they found that this supralinear summation was in a majority of the muscles, particularly in the elbow, wrist, and finger.

“This is a very interesting finding for two reasons,” explains Seki. “First, it demonstrates a particular trait of the primate spinal cord related to the increased variety of finger movements. Second, we now have direct evidence primates can use motor modules in the spinal cord to control arm movement direction and force magnitude both efficiently and independently.”

In effect, using paired stimulation in the primate spinal cord not only directly activate two groups of interneurons, INa and INb, which recruit their target muscle synergies, Syn-a and Syn-b, to set the arm trajectory, but can also activate a third set of interneurnons that can adapt the motor activity at the spinal level to change the force of the movement, group INc. This would let the brain plan the path the arm should take while the spinal cord adapts the muscle activity to make sure that path happens.

One example of this “plan and adapt” approach to motor control is the deceptively simple act of drinking from a can of soda. The brain can predetermine the best way to lift the can to your mouth for a sip, but the actual amount of soda in the can — and therefore the can’s weight — is perhaps unknown. Once your brain has determined the trajectory the can should take — in this case INa and INb — the amount of force needed to complete that action can be modulated separately in INc, rather than redetermining which sets of muscles will be needed.

This study experimentally proves for the first time that primate arm movements may be efficiently controlled by motor modules present in the spinal cord. Based on the results of this research, it is expected that the analysis and interpretation of human limb movements based on the motor module hypothesis will further advance in the future.

In the field of robotics, this control theory may lead to more efficient methods to create complex limb movements, while in the field of clinical medicine, it is expected that new diagnostic and therapeutic methods will be created by analyzing movement disorders caused by neurodegenerative diseases and strokes.

References: Amit Yaron, David Kowalski, Hiroaki Yaguchi, Tomohiko Takei, and Kazuhiko Seki, “Forelimb force direction and magnitude independently controlled by spinal modules in the macaque”, Proceedings of the National Academy of Sciences of the United States of America, 2020. DOI】https://doi.org/10.1073/pnas.1919253117

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