Primatology.net

I’m scouring the American Journal of Primatology for a paper on gorillas using tools as weapons in the wild. National Geographic News says the paper is out, but I can’t find it anywhere in the early edition nor in the current issues. I’ll continue looking, but in the mean time here’s what we got to run on (and it ain’t much)

“Researchers [doing a three year study of Cross River gorillas (Gorilla gorilla diehli)] in Cameroon have documented three cases in which the [gorillas] threw clumps of grass or tree branches at humans.”

The people who documented the behavior suggest that the gorillas possibly learned their unusual behavior from interactions with humans. Captive gorillas have been documented picking up stone throwing from their chimpanzee neighbors, so it’s not too improbably that wild gorillas could pick up grass and branch hurling from human neighbors. How did these gorillas learn the behavior? Could it be possibly due to mirror neurons? Conveniently this is a perfect transition into an upcoming PNAS paper on tool use and mirror neurons in macaques, that was announced in this ScienceNOW news article,

“To investigate how the brain performs this sleight of hand, [the team] recorded brain activity in two macaque monkeys. Each was trained for 6 to 8 months to grasp items of food with pliers. The team documented the activity of 113 neurons in F5 and in a brain area called F1, which has also been implicated in the manipulation of objects. The researchers first established the brain’s firing sequence when the monkeys grasped only with their hands. The experiment was then repeated while the monkeys used normal pliers that required first opening the hand and then closing it to grasp the food. The same neurons fired in the same order. Remarkably, the same neurons also fired, in the same order, when the monkeys used “reverse pliers” that required them to close their fingers first and then open them to take the food.”

The research is coming from the University of Parma which seems to be specializing in this sorta research because about a year and half ago they documented mirror neurons role in mimicry. In the new paper, the researchers,

“conclude that when learning to use a tool, the pattern of neuronal activity is somehow transferred from the hand to the tool, “as if the tool were the hand of the monkey and its tips were the monkey’s fingers.” As for how the same neurons could affect both the opening and the closing of the hand, the team speculates that they may be connected with other sets of neurons that more directly control these movements. The authors also point out that area F5 is rich in so-called mirror neurons, a type of nerve cell discovered earlier… that fires both when a primate performs an action and when it observes another individual doing the same thing. Mirror neurons in F5, the authors suggest, may be involved in this transfer process as a monkey learns how to use a tool by watching others.”

The first observations of gorillas using tools in the wild was made a couple years ago, and last year we saw (albeit not too convincingly) a chimp fashioning a spear to hunt, so I’m not too surprised about this news… I just wanna see it!

There’s new research coming out from Nature that shows us rhesus macaques are really tuned into statistics and probabilities, they may even have neurons specialized to calculate probabilities. But don’t get your hopes up too high… these monkeys will not be your bookies or be crunchin’ gout some gnarly ANOVA tests with p-value significance.

What you can expect, and this is all paraphrased from a New Scientist news article on this research, is what authors Tianming Yang and Michael Shadlen from Howard Hughes Medical Institute and the University of Washington have reported. They tested the reasoning capabilities of two rhesus macaques,

“By showing them a series of abstract shapes on a video screen, the monkey saw a sequence of 4 of 10 possible shapes then, had to choose which target to look at. The probability that the red target would give the reward was the sum of the probabilities for each of the four shapes; otherwise, the green target yielded the drink… both macaques learned to match their choices closely to the actual probabilities revealed by the shapes they saw, choosing the correct target more than 75% of the time.

This is the first time monkeys have been shown to make such subtle probabilistic inferences.”

Yang and Shadlen observed neurons responding to the first shape,

by firing at a rate proportional to the probability suggested by that shape. As each successive shape was shown, the firing rate changed to match the probability determined by all the shapes seen so far.

“We’re seeing neurons that are making computations,” says Shadlen. In particular, the neurons appeared to be computing the log likelihood ratio of red versus green rewards – exactly the sort of computation a statistician might do.

Like I said above, the results are published in Nature, “Probabilistic reasoning by neurons.” Hat tip to Afarensis for pointing this study out in his blog.

I consider Pakinson’s a very devastating neurodegenerative disease because the affected individuals are fully aware of their degeneration. Unlike Alzheimer’s, where individuals become jaded as the disease progresses, individuals with Parkinson’s are very conscious of what’s happening or actually what’s not functioning correctly — and they can’t do a thing about it!

So some new findings from a biomedical/neurological experiment has just come out where the authors implanted dopamine generators (dopaminergics) into brain cells of macaques. They noted these new generators improved the symptoms of Parkinson’s. Here is a summary of the methods and findings,

“the research was extended to a greater number of non- human primates and for a longer period of time. The procedure involved implanting cell fragments extracted from the carotid body in the striate area of the brain. The carotid body is a small structure located at the bifurcation of the carotid artery, at the level of the neck. Its function is to control the rhythm of respiration and the cardiac frequency through releasing dopamine in situations of low oxygen level in the blood. After the implantation of the cellular aggregates of the carotid body into the striate area of the brain, the improvement in movement in monkeys with Parkinson’s and which had received transplants was demonstrated to last for at least a year.

The research team concluded that the mechanism by which the implants in the striate area of the brain of dopamine-generating cells manage to ameliorate Parkinson’s appears to be related to the capacity of these cells to release substances (trophic factors) that induce an increase of the dopaminergic cells (that usually exist in the normal brain but in lower quantities). Amongst these trophic factors is the GNDF (Glial Cell-derived Neurotrophic Factor).

Cells extracted from the carotid body have been used as a source for dopaminergic cells in the treatment of Parkinson’s disease in animal experiments and in humans. The advantage of this cell type with respect to others is the possibility of carrying out autoimplants, thus avoiding tissue rejection or immunosupressor treatment.”

Personally, I consider this an ethical use of primates in research. Firstly, the cause is noble in my opinion. Parkinson’s is a horrible disease, and in this situation, work done on a primate model has shown us a possible way to treat the disease by inserting doapamine generators. While, I think it will be a while until we actually do that in humans, this research has allowed a possible treatment to be investigated.

If you wanna read the entire publication, here is the a link to the paper, “Modification of the number and phenotype of striatal dopaminergic cells by carotid body graft.”

The following post is a departure from my usual reporting on an interesting primate related tidbit of research. I’ll be posting about how I have thought about how to study primate brain evolution research. These are just ideas I have brainstormed. It is very probable that people are doing this out in their respective labs but I’m not in the know of what’s totally current. I hope you are interested in what scope of primate brain evolution research I will be discussion… I’ll be mostly taking in a functional genomic and computational biology approach, but that’s not to say more objective sciences such as psychology can’t fit into this game plan.

To start off, understanding primate brain evolution, specifically the biological mechanisms by how the primate brains have been positively selected for by size involves two complementary aspects of research. One of it is to identify the genes involved in brain growth and development, as well as their expression patterns. This is wet lab work, a whole lot of tissue sampling, mRNA isolation, cDNA synthesis and RT-PCR amplification, gene quantification and qualification and ultimately sequencing. At this level, one would need to sample multiple samples of representative primates (that have their genomes sequenced) and different developmental stages and populations.

Once these key players can be identified, the functions of these genes need to be well understood. Of course making knockout monkeys will be a costly and time consuming endeavor full of ethical issues, so I imagine having knockout neuron cultures can help understand the function of these genes better when they aren’t expressed. That’s a bit hard, neurons are awfully fickle to grown in culture. Maybe reporter constructs? Also, other non-traditional research such as sequence homology to other known proteins can help isolate potential functions based on structure.

Now once these key developmental genes have been classified, their relative importance should be noted… or in other words, one needs to organize which genes are specific to all primates and which are specific to fewer primates. Do these genes correlate with the known lineage of primates? If a unique pattern can be extracted, this will make the second aspect of research much easier and conclusive. This is the computational biology approach, using computers, statistics, and other mathematical models to identify what genes were mutated the most to yield the most growth. What genes remained fairly consistent? Can we estimate ages of coalescence or divergence, are there unique mutations to populations or species of primates… ultimately can we begin to make a phylogenetic tree of these genes and their changes throughout evolutionary time?

As I currently laid it out, these two field complement each other and if anything one is dependent on the other. Currently, I know of computational studies that seem to search high and low to find genes that have been positively selected for in primates by scanning and comparing entire genomes. If a hit is found, the research then shifts backwards to estimate functions based on the sequence homology to other known genes and their functions. While that maybe a useful, quick and easy approach, it’s all sorts of wrong. It is wrong because it is the needle in the haystack method. I advise one first narrow down the list, by doing the functional genomic screens, which is arduous and tedious, but much more quantitative and thorough. That way, one can limit things down to candidate genes specific to a species, developmental stage, etc. The playing field will be much more narrow and the computations will be much more conclusive.

What do you think? Do I have it right, do I have it wrong? Not to be rubbing my ego, but I think I have a thorough plan here — one that would make the most killer dissertation ever. Do you know of any researchers doing it this way? If any one out there, who reads this blog, carries out primate brain evolution research please feel free to comment and discuss. I’m really curious to know if what I have been thinking is even right.

Since primate brains and sexual dimorphism are topics that are still fresh on our minds after this morning’s post, I figured I should let you know about a new publication that came out of the open access journal BMC Biology on the differences between male and female primate brain structures and how they developed. It ain’t paleoprimatology in any sense, it’s straight up primtate neuroscience.

In “Primate brain architecture and selection in relation to sex” authors,

“Patrik Lindenfors, Charles Nunn and Robert Barton [we wrote about Dr. Barton before, here] examined data on primate brain structures in relation to traits important for male competition, such as greater body mass and larger canine teeth. The researchers also took into account the typical group size of each sex for individual primate species in order to assess sex-specific sociality – the tendency to associate with others and form social groups. The researchers then studied the differences between 21 primate species, which included chimpanzees, gorillas, and rhesus monkeys, using statistical techniques that incorporate evolutionary processes.”

What they found is pretty important, in my opinion. They have concluded that differences between primate sexes cause developmental effects on the brain, and that is due to different pressures on males and females to keep up with social or competitive demands. From News-Medical.net,

“The authors found that sexual selection had an important influence on primates brains. Greater male-on-male competition (sexual selection) correlated with several brain structures involved with autonomic functions, sensory-motor skills and aggression. Where sexual selection played a greater role the septum was smaller, and therefore potentially exercised less control over aggression.

In contrast, the average number of females in a social group correlates with the relative size of the telencephalon (or cerebrum), the largest part of the brain. The telencephalon includes the neocortex, which is responsible for higher functions such as sensory perception, generation of motor commands and spatial reasoning. Primates with the most sociable females evolved a larger neocortex, suggesting that female social skills may yield the biggest brains for the species as a whole. Social demands on females and competitive demands on males require skills handled by different brain components, the authors suggest. The contrasting brain types, a result of behavioural differences between the sexes, might be a factor in other branches of mammalian brain evolution beyond anthropoid primates, too.”

I’ve bolded the conclusions that I consider the most impacting. While, I’m weary about the how this applies to humans, I cannot deny the correlations the authors have derived. Research like this is fundamental to understanding the physical origin of very complicated social behaviors, and the authors provide us with a map of primate brains and how they correlate to sex related behaviors.

As far as how this impacts humanity — I believe human brain development is much more complex and social issues and culture imprint human brain development to a much greater degree in humans as compared to non human primates. So it’s a bit hard to say, in my opinion again, that this model of sex-selection and number of females really impact the developments of our brains.

So if you have been in the dark about what’s been making a lot of buzz around the internet today, have no worries. I’m more than happy to explain it to you, because this new research will really help us understand what it means to be human and non-human.

How, you ask?

Well, it identifies a unique protein in human brains and compares that to chimpanzees. This form of comparison is important. Often, I’ve told people that, while it maybe significant that chimpanzees and humans share a remarkable amount of genomic similarity, where we don’t share similarities, areas that span millions of base pairs, the developmental implications are really dramatic.

The research is hardcore molecular biology, specifically proteomics. Proteomics is a branch of molecular biology that seeks to determine the large scale patterns of protein expression and function. The researchers, led by Dr. Bing Su of the Chinese Academy of Sciences in Kunming, China, show,

“a certain form of neuropsin, a protein that plays a role in learning and memory, is expressed only in the central nervous systems of humans and that it originated less than 5 million years ago. The study, which also demonstrated the molecular mechanism that creates this novel protein.”

The publication, ain’t out yet. But I’m getting this all from EurekAlert, a very trustworthy pop-science news outlet run by Science. The divergence time of this protein falls in line with newly assessed dates of human lineage divergence from other great apes. So it has got that going for itself.

The specific paper will be published in Human Variation.

Su had an idea on where to look and what to compare, because her previous work had shown a longer form of the protein, neuropsin II,

“is not expressed in the prefrontal cortex (PFC) of lesser apes and Old World monkeys. In the current study, they tested the expression of type II in the PFC of two great ape species, chimpanzees and orangutans, and found that it was not present. Since these two species diverged most recently from human ancestors (about 5 and 14 million years ago respectively), this finding demonstrates that type II is a human-specific form that originated relatively recently, less than 5 million years ago.

Gene sequencing revealed a mutation specific to humans that triggers a change in the splicing pattern of the neuropsin gene, creating a new splicing site and a longer protein. Introducing this mutation into chimpanzee DNA resulted in the creation of type II neuropsin. “Hence, the human-specific mutation is not only necessary but also sufficient in creating the novel splice form,” the authors state.”

Human version of neuropsin is longer, which alters the efficacy of its function. I don’t know how, but obviously must do something better. Other conclusions have been made, but none are as significant as the ones I’ve bolded in the above quote.

I’ve decided to do some of my own research on neuropsin, to see what we know of it… where it’s located, what sorta promoters it has, etc. So I fired up NCBI’s GenBank and put in ‘neuropsin‘. Sadly, no current genomic information on the gene is up there yet. Some interesting nucleotide and protein sequences are there, as well as a cool 3d model of the protein.

Most importantly, neuropsin has been identified to function as “A Serine Protease Expressed In The Limbic System Of Mouse Brain.” A protease is an enzyme that basically breaks up things, and since serine prefixes it… neruposin functions as a breakdown component of serine, a hydrophilic amino acid that is a constituent of most proteins. Currently three human diseases are attributed to the malfunction of this enzyme, which I wonder what implications that has as far as symptoms? Reduced cognitive functions?

I also wonder why humans have this alternative modified protein in our brains and not chimpanzees, now that I know the function? Does having a second type of neuropsin allow for us to process serine more effectively, ultimately facilitating some of our cognitive differences? I know I already asked that but it is something I don’t fully understand. That’s something the authors advocate to be studied in the future, to identify,

“the biological function of type II neuropsin in humans, as the extra 45 amino acids in this form may cause protein structural and functional changes. They note that in order to understand the genetic basis that underlies the traits that set humans apart from nonhuman primates, recent studies have focused on identifying genes that have been positively selected during human evolution. They conclude, “The present results underscore the potential importance of the creation of novel splicing forms in the central nervous system in the emergence of human cognition.”

Very interesting news, none the less. Definately one of those genes to keep in the back of your head, no pun intended… really. If you like this sorta stuff, please keep in touch with me, and also check out John Hawks who published out an issue of the neuroscience blog carnival, Encephalon. I wish this post coulda made today’s issue, but I just got word of it midday! Maybe next time.

P.S. This article on ‘stalled human evolution‘ maybe also of interest. I haven’t read it yet, but with a headline like that, its bound to have some controversial stuff in it.

Well hot dang, I was reading Omni Brain the other day, where Steve broke the news that Atlanta Zoo’s orangutans play video games. But I didn’t post about it, not because it ain’t primatology related news, but because there wasn’t a video to support it. In my mind, if I can’t see it, it is less real. I think Steve operates in the same way because in his post he made a call to locate the video. One hasn’t surfaced yet, but I figured that since Engadget and Digg have posted about this news, its legitimate enough to follow suite.

From Australia’s The Age, “Gaming apes wow zoogoers” the basis of this behavior is explained,

“…Two Sumatran orangutans are part of new Zoo Atlanta research that uses computer games to study the cognitive skills of the primates.

The best part? Visitors to the US zoo get to watch their every computer move.

The orangutans play the games on a touch screen built into a tree-like structure in the habitat to blend in with their environment. Visitors watch from a monitor in front of the orangutan exhibit.”

The orangs actually have two games to play, one where its a matching game based on selecting,

“identical photographs or match orangutan sounds with photos of the animals. Correct answers mean food pellets.

There also is a painting game where they can draw pictures by moving their hands and other body parts around the screen. Printouts of their masterpieces are on display in the zoo.

The computer games test the animals’ memory, reasoning and learning, spitting out sheets of data for researchers at the zoo and Atlanta’s Center for Behavioral Neuroscience, a partner in the project.”

I like this project. I think it gives us an insight into how complex these great apes are. I hope it does raise awareness that orangutans are really endangered, as intended by the zoo officials. Another side benefit, is that this is a unique form of enrichment for the orangutans. Definitely not the the traditional ‘hide and go seek’ method of placing treats in puzzles, but equally as challenging.

I was thinking maybe one day we can get Kanzi, the Pacman playing chimp, to play these two orangutans? Perhaps we can have a LAN-party or something?

Last year, Nick Matzke of the ever informative evolutionary biology blog “The Panda’s Thumb” posted a neat little graph where he made a comparison of hominin brain sizes in relation to body sizes.

His post, “Fun with hominin brain size as a percentage of body mass” touches on one of my favorite topics in primatology, the evolution of primate brain evolution. One of the general characteristics that make primates unique are the larger brain sizes compared to body sizes in relation to other organism. His graph is limited in that it shows only the comparison of brain to body sizes of a tribe, within the family Hominidae, under a much larger taxonomic organization, the order Primates. This image (to your right) from the Encyclopædia Britannica, Inc. is a much illustrative but only depicts brain size evolution as a function of time.

This leads me to open a discussion on a fairly recent publication Evolutionary Anthropology, where Robert A. Barton, Director of the Evolutionary Anthropology Research Group at the University of Durham, U.K. addresses a much larger question,

“How did such variation evolve and why, and what are its cognitive implications?”

Robert Barton uses phylogenetic comparative methods to study the evolution of primate brains and behavior. His recent work has examined the evolution of neocortex size, the role of visual specialization in brain evolution, and ecological correlates of neural system evolution.

In the paper that I am talking about,”Primate brain evolution: Integrating comparative, neurophysiological, and ethological data,” Barton argues that people must be careful in using,

“comparative methods and in finding multiple converging strands of comparative evidence as opposed to making speculative interpretations of single correlations. In particular, recent work demonstrates the value of examining how evolutionary changes at different anatomical levels interrelate.”

What is of interest to primatologists out there, is that Barton tackles the adaptive significance of brain size in primates. He addresses a prominant assumption most people make about primates, that they are (and I’ve bolded what I consider important conclusions),

“distinguished from most other mammals by superior cognitive abilities. Large relative brain size is the most obvious justification for this view. Why did large brains evolve and what is it that they enable primates to do?

One way to tackle these questions is to examine which brain systems, with what functional properties, are associated with increased brain size. As noted, the neocortex is disproportionately expanded in primates compared with at least some other mammals, and anthropoid primates have larger neocortices than do lemurs and lorises. The fact that within primates variation in neocortex size relative to the rest of the brain is highly correlated with encephalization emphasizes the role of “neocorticalization” in primate brain expansion.

Relative expansion of the neocortex, however, reveals comparatively little about which functional systems are involved, and hence what is the adaptive significance of overall brain size. As described, the functional systems of the brain cut across the major subdivisions. No known cognitive process is mediated exclusively by the neocortex. Complex cognitive processes are mediated by networks that link the neocortex with many other structures. Furthermore, the neocortex is a highly heterogenous organ, processing information from all the senses and being involved in many different aspects of sensory, motor, and cognitive processing. Hence, the neocortex is necessary for many cognitive functions but sufficient for none. It is therefore misleading to view the neocortex as the “cognitive” part of the brain. As with overall brain size, we still need to identify the specific systems in which selective expansion accounts for the increase in overall neocortex size and hence, in brain size. “

Barton goes on to show how other fields have made premature conclusions. Since we know so little about the function of the brain, he wraps up his paper with an argument that we need a greater understanding of brain evolution, one which

“depends on studying and interrelating evolutionary change at a variety of levels, from microscopic to macroscopic anatomy and from neural systems to behavioral ecology. While it has been fashionable in some circles to denigrate brain size as a crude measure of cognitive abilities, to an evolutionary biologist the manifest variation in brain size is intrinsically interesting and demanding of an explanation. Yet, in order to explain variation in brain size we need to understand which systems, with what functional properties, contribute to it, and what constraints act on it. Conversely, cognitive neuroscience may learn valuable lessons from phylogenetic comparative studies.”

I completely side with this advice Barton has given, however I don’t know how that will stop or prevent people from making conclusions in general. Many evolutionary biologists like Lewontin, Gould, etc. have argued (in the 70′s!) that we should not make ‘adaptionist’ stories to justify why we see certain adaptations… but it is still prevalent to this day.

Also, let me personally interject on Barton’s advice by adding that in order to understand primate brain evolution we also need to decipher a larger understanding of comparative and functional genomics between primates. We need to understand what genes are facilitating the development of primate brains, and how they have changed throughout evolutionary time.

BBC News recently reported on a pretty interesting three-year long research project that is not the typical non-human primate-focused research we usually highlight on this site, but I couldn’t resist bringing it up. The project, FEELIX Growing, a multi-national project is aiming to create robots that read and react to humans in an appropriate manner.

Dr. Lola Canamero, coordinator of the project, from the University of Hertfordshire:

“We are most interested programming and developing behavioural capabilities, particularly in social and emotional interactions with humans.”

Here’s the project summary:

“If robots are to be truly integrated in humans’ everyday environment in order to provide services such as company, caregiving, entertainment, patient monitoring, aids in therapy, etc., they cannot be simply designed and taken off the shelf to be directly embedded into a real-life setting. Adaptation to incompletely known and changing environments and personalization to their human users and partners are necessary features to achieve successful long-term integration. This integration would require that, like children (but on a shorter time-scale), robots develop embedded in the social environment in which they will fulfill their roles. The overall goal of this project is the interdisciplinary investigation of socially situated development from an integrated or global perspective, as a key paradigm towards achieving robots that interact with humans in their everyday environments in a rich, flexible, autonomous, and user-centred way. To achieve this general goal we set the following specific objectives:

1. Identification of scenarios presenting key issues and typologies of problems in the investigation of global socially situated development of autonomous (biologically and robotic) agents.
2. Investigation of the roles of emotion, interaction, expression, and their interplays in bootstrapping and driving socially situated development, which includes implementation of robotic systems that improve existing work in each of those aspects, and their testing in the key identified scenarios.
3. Integration of (a) the above capabilities in at least 2 different robotic systems, and (b) feedback across the disciplines involved.
4. Identification of needs and key steps towards achieving standards in: (a) the design of scenarios and problem typologies, (b) evaluation metrics, (c) the design of robotic platforms and related technology that can be realistically integrated in people’s everyday life.

FEELIX GROWING takes a highly interdisciplinary approach that combines theories, methods, and technology from developmental and comparative psychology, neuroimagery, ethology, and autonomous and developmental robotics, to investigate how socially situated development can be brought to robots that grow up and adapt to humans in everyday environments. We expect to have a significant impact on the scientific community, on two grounds. On the one hand, our research focus poses an important and as-yet largely unexplored scientific question that is increasingly recognized as a keystone in the development of human-oriented social technology and in the understanding of humans, and can contribute to the advancement of entertainment, developmental, service, and rehabilitation robotics. On the other hand, our strongly interdisciplinary effort could make important contributions to a number of disciplines and set the grounds towards long-term collaborations among them.”

The description of the robot itself is quite reminiscent of a family pet (or a service animal) in that it is

“to be truly integrated in humans’ everyday environment in order to provide services such as company, caregiving, entertainment, patient monitoring, aids in therapy, etc.”

With that in mind, I couldn’t help but think about the vastly different perceptions science has on the animal mind (some may say that I’m a bit obsessed about it). It’s fascinating that we as a scientific community are on the verge of creating a machine (or more specifically software) with the capabilities to “learn from humans and respond in a socially and emotionally appropriate manner,” yet frequently deny this ability in non-human animals.

It’s frustrating to work with a scientist that comes into their lab telling stories of how when he got home last night, he could immediately tell that his golden retriever, Harry, did something wrong based upon the look on his face alone… and then proceed to close off all thought about the possibility that his subjects share those emotions. He of course will say that he is simply being objective. But couldn’t one argue that not taking into account all of your subject’s abilities be a hindrance to your objectivity?

This is not to suggest that we should bias our opinions based on what happens at home, but to suggest that we as humans are the only emotional beings appears to be a bit arrogant. I feel that not taking a chance and hiding behind scientific precedents (potentially to save one’s career) is a hindrance upon what we can discover. Sure new theories and thoughts can be intimidating, but exploring those in an objective manner is what we thrive upon… it’s why we do what we do.

Please don’t take this the wrong way, I’m not saying that this is something I’m seeing in the FEELIX Growing project, it’s just some thoughts that have popped up while reading about their interesting project… and it leaves me wondering what will come from this project in terms of the animal mind.

A big topic of conversation in zoos and other animal facilities is stress: Who suffers from it? What are the causes and repercussions? How can we identify it biologically? And what are the best ways to recognize the causes in hopes of alleviating the stress?

We have all seen stress in animals (including ourselves) appear in some form of aberrant behaviors and other various conditions: pacing, head tossing (with carnivores), hypergrooming, displaying (like throwing feces or vomit), losing sleep, breaking out into hives, and self mutilation, just to name a few. While these behaviors and conditions are visual, concern also lies in what we can’t easily see… chronic stress resulting in suppression of the immune system, high blood pressure, stress dwarfism, fibrosing cardiomyopathy, etc.

Robert Sapolsky of Stanford University has been researching the physiological effects of stress on health (with a nice set of publications including both scientific papers and popular books) for decades and recently presented at the American Association for the Advancement of Science in San Francisco on Feb 17^th, 2006 (which I’m sad to say I missed). ScienceDaily highlights his research asking “Why Do Humans And Primates Get More Stress-related Diseases Than Other Animals?”

The bottom line is that:

“Primates are super smart and organized just enough to devote their free time to being miserable to each other and stressing each other out. But if you get chronically, psychosocially stressed, you’re going to compromise your health. So, essentially, we’ve evolved to be smart enough to make ourselves sick.”

Sapolsky helps us to think of it in terms of real stress versus psychological stress:

“During real stress – for example, something is intent on eating you and you’re running for your life – versus what your body does when you’re turning on the same stress response for months on end for purely psychosocial reasons.”

By constantly stressing ourselves out we are forcing our bodies to run in ways that are only intended for short bursts of time. We are essentially breaking down our system and becoming vulnerable to severe health problems (like those previously mentioned).

The baboon studies Sapolsky spearheaded are hugely relevant to this situation:

“We’ve found that baboons have diseases that other social mammals generally don’t have. If you’re a gazelle, you don’t have a very complex emotional life, despite being a social species. But primates are just smart enough that they can think their bodies into working differently. It’s not until you get to primates that you get things that look like depression.

The reason baboons are such good models is, like us, they don’t have real stressors. If you live in a baboon troop in the Serengeti, you only have to work three hours a day for your calories, and predators don’t mess with you much. What that means is you’ve got nine hours of free time every day to devote to generating psychological stress toward other animals in your troop. So the baboon is a wonderful model for living well enough and long enough to pay the price for all the social-stressor nonsense that they create for each other. They’re just like us: They’re not getting done in by predators and famines, they’re getting done in by each other.”

Needless to say, it’s important to understand more of the neuroscience behind stress. Sapolsky highlights some of the new research:

“It’s becoming clear that in the hippocampus, the part of the brain most susceptible to stress hormones, you see atrophy in people with post-traumatic stress disorder and major depression. There’s a ton of very exciting, very contentious work as to whether stress is causing that part of the brain to atrophy, and if so, is it reversible. Or does having a small hippocampus make you more vulnerable to stress-related traumas?”

Also…

“There are now studies showing that chromosomal DNA aging accelerates in young, healthy humans who experience something incredibly psychologically stressful. That’s a huge finding.”

Animals respond differently to every situation and stress is no exception. Understanding these differences, according to Sapolsky, is one of the most important areas of neuroscience research:

“This gets you into the realm of why do some people see stressors that other people don’t, and why, in the face of something that is undeniably a stressor to everybody, do some people do so much worse than others?”

It will be interesting to see how this research unfolds. Will it result in solid methods to understand how stress works? Will it lead to non-invasive biological markers of stress? Currently some researchers are relying on cortisol as a hormonal marker of stress. I’ve been to many a lecture reviewing the pros and cons of using cortisol in behavioral research, each generally ending with the same thought: cortisol is an accurate marker telling us that something is happening, but whether that something is bad stress (versus good stress, like riding a roller coaster) is still unknown. Some may say that the captive situations we’re using in research are more likely to prompt bad stress which would mean that cortisol is a better marker of bad stress than we are giving it credit for, but until that separation is apparent, we’re kind of back to the drawing board.

Understanding the animals that we work with can sometimes be a challenging job. Hopefully with all of the research going on in this field, we will be able to formulate a better understanding of what stress is (for each individual animal) so that we can do our best to identify and eliminate the stressors (and consequently the health problems).