Environmental Factors Determine Whether Immigrants Are Accepted by Cooperatively Breeding Animals

Feb. 6, 2013 — Cichlid fish are more likely to accept immigrants into their group when they are under threat from predators and need reinforcements, new research shows. The researcher suggests that there are parallels between cooperatively breeding fish’s and humans’ regulation of immigrants. The research was published February 6, 2013, in the journalProceedings of the Royal Society B.


The Princess of Lake Tanganyika (Neolamprologus pulcher), a cichlid fish which is popular in home aquariums, are cooperatively breeding fish with a dominant breeding pair and several ‘helper’ fish that do not normally breed but instead assist with raising offspring. Helpers also play a crucial role in defending the group’s territory against outsiders — although helpers also compete with the breeders for resources and reproductive opportunities.

The researchers, led by Dr Markus Zӧttl of the University of Cambridge, wanted to find out how environmental pressures might influence the acceptance of new immigrants. Zӧttl, who conducted the research while at the University of Bern, said: “All animal societies are affected in one or another by immigration and when we seek to understand social organisation we need to understand which environmental factors influence processes like immigration.”

A subdivided tank was used to carry out a series of tests in which different scenarios were observed. For the study, a breeding pair (which would be responsible for deciding whether a newcomer would be allowed to join the group) was placed in one compartment next to a compartment containing either a fish predator, an egg predator, a herbivore fish or no fish at all. An immigrant was placed in a third, adjoining compartment. The breeding pair was then exposed to the different fish in compartment two. The researchers then observed whether the type of fish they were exposed to would affect whether they accepted the immigrant fish from the third compartment.

The researchers found that breeders are less aggressive to immigrants and more likely to accept the unknown and unrelated fish as a member of their group when they are simultaneously exposed to predators. They concluded that cichlid fish are more likely to accept immigrants into their group when they are under threat from predators and can be used to increase their defences.

Dr Zӧttl added: “Our fish resemble human societies’ view of immigration in two crucial aspects: The need for help in the territory takes precedence, and it seems to be a strategy of the territory holders to accept immigrants only when they need assistance with territory defence. This resembles human societies which organise immigration according to the demand in the society by encouraging skilled immigration when certain types of labour are in short supply.”

The researchers also found that the fish appear to consider future threats. When egg predators were presented to a breeding pair who had not yet spawned they accepted new incomers. Their acceptance of reinforcements in the form of immigrant fish suggests that that the egg predator was viewed as a threat.

Dr Zӧttl concluded: “This behaviour suggests that breeders of this species might be able to anticipate a potential threat — and it seems to resemble the future planning evident in birds and apes.”


Story Source:

The above story is reprinted from materials provided byUniversity of Cambridge. The original story is licensed under a Creative Commons license.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


University of Cambridge (2013, February 6). Environmental factors determine whether immigrants are accepted by cooperatively breeding animals. ScienceDaily. Retrieved February 7, 2013, from http://www.sciencedaily.com/releases/2013/02/130206094716.htm

Nothing Fishy About Swimming With Same-Sized Mates

Feb. 6, 2013 — Same-sized fish stick together, using chemical cues to identify each other.


Have you ever wondered why, and how, shoals of fish are composed of fish of the same size? According to new research by Ashley Ward, from the University of Sydney in Australia, and Suzanne Currie, from Mount Allison University in Canada, fish can use a variety of different sensory cues to locate shoal-mates, but they are able to use chemical cues to find other fish of the same size as themselves. Using these cues, they can form a group with strength in numbers. The work is published online in Springer’s journal, Behavioral Ecology and Sociobiology.

Forming groups is beneficial for animals. One important benefit is the reduction of individual risk from predators. Indeed when animals are in groups, predators are confronted by a number of almost identical prey animals, making it more challenging to select a target.

Dr. Ward said, “Fish typically form shoals with fish of the same size. The key question that motivated our study is this: How on earth does a fish know how big it is? For humans this is trivial — we can stand on a flat surface and see whether we’re taller or shorter than someone, or we can look in a mirror. These options don’t exist for fish, so how do they choose to associate with fish of the same size?”

The scientists explored which of their senses fish use both to assess the size of other individuals, and to determine how big they are themselves. They studied two freshwater shoaling fish species: three-spined stickleback and banded killfish. In a series of experiments, they exposed the fish to a variety of chemical cues — either from fish of the same species of varying sizes or a control, so-called ‘blank’ cue. Chemical cues are formed as fish constantly emit molecules into their surroundings.

Ward continued, “We know the sense of smell is well developed in fish and that they are sensitive to tiny differences in the chemical signature given off by others. So could they smell how big they are themselves and use this as a template to assess the size of others? It seems they can.”

Both species of shoaling fish preferred the chemical cues of same-sized fish than those of larger or smaller fish from their own species. This suggests that the fish were able to determine their own size relative to other fish of the same species, primarily through chemical self-referencing.

“Using chemical cues to locate similarly sized fish of the same species in the wild promotes the formation of shoals, which creates confusion for predators as well as more coordinated, and potentially efficient, patterns of behavior for both activity and nutrition,” concluded Ward.

 

Story Source:

The above story is reprinted from materials provided bySpringer Science+Business Media.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Ashley J. W. Ward, Suzanne Currie. Shoaling fish can size-assort by chemical cues aloneBehavioral Ecology and Sociobiology, 2013; DOI: 10.1007/s00265-013-1486-9
Springer Science+Business Media (2013, February 6). Nothing fishy about swimming with same-sized mates. ScienceDaily. Retrieved February 7, 2013, from http://www.sciencedaily.com/releases/2013/02/130206093909.htm

Overall Eating Patterns Are Most Important for Healthful Eating

Feb. 5, 2013 — The overall pattern of food that a person eats is more important to a healthy diet than focusing on single foods or individual nutrients, according to the Academy of Nutrition and Dietetics in its newly updated position paper “Total Diet Approach to Healthy Eating.”


According to the position paper: “In contrast to the total diet approach, classification of specific foods as ‘good’ or ‘bad’ is overly simplistic and may foster unhealthy eating behaviors.” The Academy’s position paper stresses that moderation, portion size and exercise are the key concepts for balancing food and beverage intakes.

The position paper has been published in the February Journal of the Academy of Nutrition and Dietetics and can be found on the Academy’s website. It states: It is the position of the Academy of Nutrition and Dietetics that the total diet or overall pattern of food eaten is the most important focus of healthy eating. All foods can fit within this pattern, if consumed in moderation with appropriate portion size and combined with physical activity. The Academy strives to communicate healthy eating messages that emphasize a balance of food and beverages within energy needs, rather than any one food or meal.

The Academy’s position paper has been updated to reflect the most current nutrition guidance, such as the 2010 Dietary Guidelines for Americans and the USDA’s MyPlate food guidance system; the White House’s Let’s Move! campaign to reduce childhood obesity and Healthy People 2020. Each of these public policies and dietary patterns supports the total diet approach.

According to the position paper, while studies including the Academy’s “Nutrition and You” national consumer survey show Americans are “conscious of the importance of healthy diets and physical activity,” most people do not meet the recommendations of the Dietary Guidelines. For example, large majorities do not eat fruit (68 percent) or vegetables (74 percent) more than twice a day, and a substantial number (36 percent) engage in no leisure-time physical activity.

In that environment, according to the Academy: “Labeling specific foods in an overly simplistic manner as ‘good foods’ and ‘bad foods’ is not only inconsistent with the total diet approach, but it may cause many people to abandon efforts to make dietary improvements.”

The position paper adds: “In 2011, 82 percent of U.S. adults cited not wanting to give up foods they like as a reason for not eating healthier. For these reasons, the concepts of moderation and proportionality are necessary components of a practical, action-oriented understanding of the total diet approach.”

The Academy’s position paper notes that the most recent Dietary Reference Intakes use a total diet approach because it allows for a broad range of foods to meet a person’s nutrition needs over time. Therefore, a person can make diet choices based on individual preferences, genetic background, personal health status and food availability.

The position paper was written by registered dietitians Jeanne Freeland-Graves, Bess Heflin Centennial Professor in the department of nutritional sciences at the University of Texas — Austin; and Susan Nitzke, professor emerita and extension specialist in nutritional sciences at the University of Wisconsin — Madison.

The Academy’s position paper contains advice and recommendations for health professionals as well as consumers. It explains how food and nutrition practitioners can use behavioral theories and models to develop effective nutrition communications; and how food and beverage choices are affected by multiple factors that influence people’s ability to make use of expert advice on healthy eating.

Updated sections of the position paper look at new indicators of nutrient quality, such as the Nutrient Rich Food Index, the European Union Nutrient Profiling System and the Overall Nutrient Quality Index. In addition, the Social Ecological model, used in the Dietary Guidelines, is incorporated into the Academy’s position as “a guide for understanding why we eat what we do.”

According to the Academy’s position paper: “Food and nutrition practitioners have a responsibility to communicate unbiased food and nutrition information that is culturally sensitive, scientifically accurate, medically appropriate and tailored to the needs and preferences of the target audience. Some health and nutrition professionals and many ‘pseudo-experts’ promote specific types of foods to choose or avoid. A more responsible and effective approach is to help consumers understand and apply the principles of healthy diet and lifestyle choices. Unless there are extenuating circumstances (severe cognitive or physical limitations), the total diet approach is preferred because it is more consistent with research on effective communication and inclusive of cultural/personal differences.”

Abstract: http://www.eatright.org/About/Content.aspx?id=8356


Story Source:

The above story is reprinted from materials provided byAcademy of Nutrition and Dietetics.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Academy of Nutrition and Dietetics (2013, February 5). Overall eating patterns are most important for healthful eating. ScienceDaily. Retrieved February 6, 2013, from http://www.sciencedaily.com/releases/2013/02/130205123008.htm

Meerkat Predator-Scanning Behavior Is Altruistic, Research Suggests

Feb. 4, 2013 — In order to spot potential predators, adult meerkats often climb to a higher vantage point or stand on their hind legs. If a predator is detected, they use several different alarm calls to warn the rest of the group. New Cambridge research shows that they are more likely to exhibit this behaviour when there are young pups present, suggesting that the predator-scanning behaviour is for the benefit of the group rather than the individual.


Meerkats are a cooperatively breeding species, with a dominant breeding pair and up to 40 ‘helpers’ of both sexes who do not normally breed but instead assist with a number of cooperative activities such as babysitting and feeding of offspring.

However, scientists have questioned whether sentinel behaviour, when helper meerkats climb to a high point to scan for predators, and other vigilance behaviour, such as standing on their hind legs, is done for their own preservation (with the group’s increased safety being an indirect consequence) or if the primary goal is altruistic, with the main purpose being the protection of the group.

Peter Santema, a PhD student at the University of Cambridge’s Department of Zoology, said: “You see similar behaviour in a range of mammal and bird species, and we know from previous work that other group members are less likely to be attacked by predators when someone is on guard. Biologists have been debating, however, whether the protection that other group members enjoy is just a side-effect or one of the reasons why individuals perform these guarding behaviours.”

For the research, which was funded by the BBSRC, scientists observed non-breeding helpers in the period just before the dominant female’s pups had joined the group on foraging trips. They repeated the observations immediately after the pups joined the group. When they compared the results, they found that after the pups had joined the group on foraging trips, helpers showed a sudden increase in their vigilance behaviour.

Santema added: “These results are exciting, as they show us that individuals are not just on the look-out for their own safety, but that the protection of other group members is another motivation for these behaviours. Our results thus suggest that vigilance and sentinel behaviour in meerkats represent forms of cooperation.”

The Cambridge research was published today in the journalAnimal Behaviour.

 

Story Source:

The above story is reprinted from materials provided byUniversity of Cambridge. The original story is licensed under a Creative Commons license.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


University of Cambridge (2013, February 4). Meerkat predator-scanning behavior is altruistic, research suggests. ScienceDaily. Retrieved February 5, 2013, from http://www.sciencedaily.com/releases/2013/02/130204220845.htm

Paired Genes in Stem Cells Shed New Light On Gene Organization and Regulation

Feb. 4, 2013 — Whitehead Institute researchers have determined that DNA transcription, the process that produces messenger RNA (mRNA) templates used in protein production, also runs in the opposite direction along the DNA to create corresponding long noncoding RNAs (lncRNAs). Moreover, the mRNAs and lncRNAs are transcribed coordinately as stem cells differentiate into other cell types. This surprising finding could redefine our understanding of gene organization and its regulation.

“It’s a surprise to me that genes come in pairs,” says Whitehead Member Richard Young, who is also a professor of biology at MIT. “At any one of the 20,000 protein-coding genes that are active in human stem cells, a lncRNA gene located upstream is also transcribed. So much effort has gone into studying protein-coding genes, and yet we have missed this concept that all protein-coding genes come in mRNA/lncRNA pairs. If you activate the mRNA gene, you’re going to activate the lncRNA gene.”

Young and his lab report their findings this week in theProceedings of the National Academy of Sciences (PNAS).

Until now, scientists thought transcription machinery attaches to DNA at certain points called promoters and moves just in one direction along the DNA to create mRNAs from protein-coding genes. Other RNAs that are not protein templates, including lncRNAs, are also created by transcription, but despite their important roles in in regulation of gene expression, development and disease, scientists knew little about how lncRNA transcription is initiated or where most lncRNA genes reside in the genome.

By looking at human and mouse embryonic stem cells, researchers in the Young lab found something astonishing — most lncRNA genes are located adjacent mRNA genes, and the transcription of about 65% of lncRNAs originates at active promoters associated with these mRNAs’ genes and runs “upstream” and in the opposite direction from the promoter.

When the transcription machinery attaches to a promoter, it seems that it is just as likely to move in one direction and transcribe the mRNA as it is to move in opposite direction and transcribe the neighboring lncRNA.

The researchers also noticed that as embryonic stem cells begin differentiating into other cell types, the mRNA/lncRNA pairs are regulated in the same way — the transcription of paired mRNAs and lncRNAs is upregulated or downregulated together. This further confirms the relationship between the transcription of mRNAs and lncRNAs.

“I think it’s quite a breakthrough,” says Alla Sigova, who is a postdoctoral researcher in the Young lab and a co-author of the paper in PNAS. “This provides a unifying principle for production of mRNAs and lncRNAs, and may lead to new insights into lncRNA misregulation in disease. For example, some mRNAs are up- or downregulated in cancer, so their lncRNA partners could potentially contribute to cancer.”

This work was supported by National Institutes of Health Grants HG002668, GM34277, and DK090122, the American Gastroenterological Association, the Damon Runyon Cancer Research Foundation, and National Cancer Institute Cancer Center Support (Core) Grant P30-CA14051.


Story Source:

The above story is reprinted from materials provided byWhitehead Institute for Biomedical Research. The original article was written by Nicole Giese Rura.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Alla A. Sigova, Alan C. Mullen, Benoit Molinie, Sumeet Gupta, David A. Orlando, Matthew G. Guenther, Albert E. Almada, Charles Lin, Phillip A. Sharp, Cosmas C. Giallourakis, and Richard A. Young. Divergent transcription of long noncoding RNA/mRNA gene pairs in embryonic stem cellsPNAS, 2013 DOI:10.1073/pnas.1221904110
Whitehead Institute for Biomedical Research (2013, February 4). Paired genes in stem cells shed new light on gene organization and regulation. ScienceDaily. Retrieved February 5, 2013, from http://www.sciencedaily.com/releases/2013/02/130204153608.htm

Grooming Helps Insects Keep Their Senses Sharpened

Feb. 4, 2013 — Like a self-absorbed teenager, insects spend a lot of time grooming. In a study that delves into the mechanisms behind this common function, North Carolina State University researchers show that insect grooming — specifically, antennal cleaning — removes both environmental pollutants and chemicals produced by the insects themselves.

These are electron microscopy images of ungroomed, groomed and hexane washed male cockroach antennae. Grooming keeps olfactory senses keen. (Credit: NC State University)

The findings, published online this week in Proceedings of the National Academy of Sciences, show that grooming helps insects maintain acute olfactory senses that are responsible for a host of functions, including finding food, sensing danger and even locating a suitable mate.

The findings could also explain why certain types of insecticides work more effectively than others.

Insects groom themselves incessantly, so NC State entomologist Coby Schal and post-doctoral researchers Katalin Boroczky and Ayako Wada-Katsumata wanted to explore the functions of this behavior.

They devised a simple set of experiments to figure out what sort of material insects were cleaning off their antennae, where this material was coming from, and the differences between how groomed and ungroomed antennae functioned. Schal likened the straightforwardness of some of the experiments to something you’d see in a well-equipped high-school science lab.

The researchers compared cleaned antennae of American cockroaches with antennae that were experimentally prevented from being cleaned. They found that grooming cleaned microscopic pores on the antennae that serve as conduits through which chemicals travel to reach sensory receptors for olfaction. Cockroaches clean their antennae by using forelegs to place the antennae in their mouths; they then methodically clean every segment of the antenna from base to tip.

The researchers found that both volatile and non-volatile chemicals accumulated on the ungroomed antennae of cockroaches, but most surprising was the accumulation of a great deal of cuticular hydrocarbons — fatty, candlewax-like substances secreted by the roaches to protect them against water loss.

“It is intuitive that insects remove foreign substances from their antennae, but it’s not necessarily intuitive that they groom to remove their ‘own’ substances,” Schal says.

The researchers also tested groomed and ungroomed cockroach antennae to gauge how well roaches picked up the scent of a known sex pheromone compound, as well as other odorants. Clean antennae responded to these signals much more readily than ungroomed antennae.

The researchers then put carpenter ants, houseflies and German cockroaches to many of the same tests. Although they groom a bit differently than cockroaches — flies and ants seem to rub their legs over their antennae to remove particulates, with ants then ingesting the material off their legs — the tests showed that these insects also accumulated more cuticular hydrocarbons when antennae went ungroomed.

“The evidence is strong: Grooming is necessary to keep these foreign and native substances at a particular level,” Schal says. “Leaving antennae dirty essentially blinds insects to their environment.”

Schal adds that there could be pest-control implications to the findings. An insecticide mist or dust that settles on a cockroach’s antennae, for instance, should be ingested by the roach rather quickly due to constant grooming. That method of insecticide delivery could be more effective than relying on residual insecticides to penetrate the thick cuticle, for instance.

Finally, Schal says the study can also be used as a caution to other researchers who use insects in experiments. Gluing shut an insect’s mouth to prevent it from feeding, for example, also prevents the insect from grooming its antennae. Experimental results could be skewed as a result of this sensory deprivation, Schal suggests.

Dale Batchelor, a researcher in NC State’s Analytical Instrumentation Facility, co-authored the paper, as did Marianna Zhukovskaya at the Russian Academy of Sciences. The research was supported by the National Institute of Food and Agriculture, the U.S. Department of Agriculture, the National Science Foundation and the Blanton J. Whitmire Endowment at NC State.


Story Source:

The above story is reprinted from materials provided byNorth Carolina State University.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Katalin Böröczky, Ayako Wada-Katsumata, Dale Batchelor, Marianna Zhukovskaya, and Coby Schal.Insects groom their antennae to enhance olfactory acuityPNAS, February 4, 2013 DOI:10.1073/pnas.1212466110
North Carolina State University (2013, February 4). Grooming helps insects keep their senses sharpened. ScienceDaily. Retrieved February 5, 2013, from http://www.sciencedaily.com/releases/2013/02/130204153603.htm

Finding the Way to Memory: Receptor Plays Key Role in Regulating Plasticity of Brain’s Nerve Cell Connections

Feb. 4, 2013 — Our ability to learn and form new memories is fully dependent on the brain’s ability to be plastic — that is to change and adapt according to new experiences and environments. A new study from the Montreal Neurological Institute — The Neuro, McGill University, reveals that DCC, the receptor for a crucial protein in the nervous system known as netrin, plays a key role in regulating the plasticity of nerve cell connections in the brain. The absence of DCC leads to the type of memory loss experienced by Dr. Brenda Milner’s famous subject HM. Although HM’s memory loss resulted from the removal of an entire brain structure, this study shows that just removing DCC causes the same type of memory deficit.


The finding published in this week’s issue of Cell Reports, extends Dr. Milner’s seminal finding to another level, revealing a key part of the molecular basis for learning and memory.

Although both netrin and DCC are essential for normal development (in terms of guiding nerve cell growth) until now their function in the adult brain was not known. Dr. Tim Kennedy, lead researcher and neuroscientist at The Neuro, contributed to the discovery of netrins as a young post-doctoral fellow. This new study reveals the answer to the question that drove him to first start a lab. “I remember that exact moment when I knew I could run a research lab, it was 1993 and I was studying the developing nervous system and I was amazed to spot netrins in the adult brain — raising the important question, ‘what are they doing there?’ 20 years of dedicated research later the answer provides an important piece of the puzzle for understanding our nervous system and neurological disorders.

“The power of this study is that it looks at the animal on all levels, molecular, structural, and behavioural. We show that the netrin receptor DCC is a critical component of synapses between neurons in the adult brain, and is required for synapses to function properly. To demonstrate this, we selectively removed DCC from a specific subset of neurons in the adult mouse brain. This results in progressive degeneration of synapses, leading to defects in synaptic plasticity and memory. The synapses continue to function in that they still communicate but, the synapses cannot adjust or change in response to new experiences. Therefore, you can’t learn anymore.”

Furthermore, DCC deletion from mature neurons results in changes in the shape of specialized protrusions called dendritic spines, and alters the NMDA receptor, a critical trigger for mechanisms that make changes in synaptic strength. Therefore the study reveals that DCC is required to maintain proper synapse morphology or shape, and to regulate the ability of the NMDA receptor to switch on, which ensures activity-dependent synaptic plasticity.

Mutant mice that entirely lack DCC in all cells do not survive past birth and exhibit major defects in brain development. In order to investigate the function of netrin in the adult brain, researchers from the Netherlands Cancer Institute, collaborators on this study, engineered a new strain of floxed mice, in which the DCC gene can be selectively deleted from a specific sub-set of cells. Floxing involves putting short sequences of DNA on either side of a gene sequence. An enzyme that is activated later in life then recombines the DNA and cuts out the intervening sequence — deleting the gene only from specific cells. The Kennedy lab activated this enzyme only in the mature mouse brain, and limited activation to only a subset of neurons, consequently deleting the DCC gene from only from these neurons. These mice live to adulthood (DCC is made normally in all other cells in the mouse) as the enzyme only turns on and deletes DCC in specific cells in the adult brain. Although the mice otherwise appear normal, testing their behavior revealed severe deficits in their ability to form certain types of new long-term memories.

This study provides important new insight into the neural mechanisms of learning and memory, processes that are fundamental to our existence, survival, and everyday life.

This research was funded by the Canadian Institutes of Health Research. Dr. Kennedy is a Chercheur national of the Fonds de recherche du Québec — Santé and a Scholar of the Killam Trusts.

 

Story Source:

The above story is reprinted from materials provided byMcGill University.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Katherine E. Horn, Stephen D. Glasgow, Delphine Gobert, Sarah-Jane Bull, Tamarah Luk, Jacklyn Girgis, Marie-Eve Tremblay, Danielle McEachern, Jean-François Bouchard, Michael Haber, Edith Hamel, Paul Krimpenfort, Keith K. Murai, Anton Berns, Guy Doucet, C. Andrew Chapman, Edward S. Ruthazer, Timothy E. Kennedy. DCC Expression by Neurons Regulates Synaptic Plasticity in the Adult BrainCell Reports, 2013; 3 (1): 173 DOI:10.1016/j.celrep.2012.12.005
McGill University (2013, February 4). Finding the way to memory: Receptor plays key role in regulating plasticity of brain’s nerve cell connections. ScienceDaily. Retrieved February 5, 2013, from http://www.sciencedaily.com/releases/2013/02/130204142644.htm

Human Brain Is Divided On Fear and Panic: Different Areas of Brain Responsible for External, Internal Threats

Feb. 4, 2013 — When doctors at the University of Iowa prepared a patient to inhale a panic-inducing dose of carbon dioxide, she was fearless. But within seconds of breathing in the mixture, she cried for help, overwhelmed by the sensation that she was suffocating.


The patient, a woman in her 40s known as SM, has an extremely rare condition called Urbach-Wiethe disease that has caused extensive damage to the amygdala, an almond-shaped area in the brain long known for its role in fear. She had not felt terror since getting the disease when she was an adolescent.

In a paper published online Feb. 3 in the journal Nature Neuroscience, the UI team provides proof that the amygdala is not the only gatekeeper of fear in the human mind. Other regions — such as the brainstem, diencephalon, or insular cortex — could sense the body’s most primal inner signals of danger when basic survival is threatened.

“This research says panic, or intense fear, is induced somewhere outside of the amygdala,” says John Wemmie, associate professor of psychiatry at the UI and senior author on the paper. “This could be a fundamental part of explaining why people have panic attacks.

If true, the newly discovered pathways could become targets for treating panic attacks, post-traumatic stress syndrome, and other anxiety-related conditions caused by a swirl of internal emotional triggers.

“Our findings can shed light on how a normal response can lead to a disorder, and also on potential treatment mechanisms,” says Daniel Tranel, professor of neurology and psychology at the UI and a corresponding author on the paper.

Decades of research have shown the amygdala plays a central role in generating fear in response to external threats. Indeed, UI researchers have worked for years with SM, and noted her absence of fear when she was confronted with snakes, spiders, horror movies, haunted houses, and other external threats, including an incident where she was held up at knife point. But her response to internal threats had never been explored.

The UI team decided to test SM and two other amygdala-damaged patients with a well-known internally generated threat. In this case, they asked the participants, all females, to inhale a gas mixture containing 35 percent carbon dioxide, one of the most commonly used experiments in the laboratory for inducing a brief bout of panic that lasts for about 30 seconds to a minute. The patients took one deep breath of the gas, and quickly had the classic panic-stricken response expected from those without brain damage: They gasped for air, their heart rate shot up, they became distressed, and they tried to rip off their inhalation masks. Afterward, they recounted sensations that to them were completely novel, describing them as “panic.”

“They were scared for their lives,” says first author Justin Feinstein, a clinical neuropsychologist who earned his doctorate at the UI last year.

Wemmie had looked at how mice responded to fear, publishing a paper in the journal Cell in 2009 showing that the amygdala can directly detect carbon dioxide to produce fear. He expected to find the same pattern with humans.

“We were completely surprised when the patients had a panic attack,” says Wemmie, also a faculty member in the Iowa Neuroscience Graduate Program.

By contrast, only three of 12 healthy participants panicked — a rate similar to adults with no history of panic attacks. Notably, none of the three patients with amygdala damage has a history of panic attacks. The higher rate of carbon dioxide-induced panic in the patients suggests that an intact amygdala may normally inhibit panic.

Interestingly, the amygdala-damaged patients had no fear leading up to the test, unlike the healthy participants, many who began sweating and whose heart rates rose just before inhaling the carbon dioxide. That, of course, was consistent with the notion that the amygdala detects danger in the external environment and physiologically prepares the organism to confront the threat.

“Information from the outside world gets filtered through the amygdala in order to generate fear,” Feinstein says. “On the other hand, signs of danger arising from inside the body can provoke a very primal form of fear, even in the absence of a functioning amygdala.”

Contributing authors include Colin Buzza, Robin Follmer, and William Coryell, from the UI Department of Psychiatry; Rene Hurlemann, from the University of Bonn Department of Psychiatry; Nader Dahdaleh, of the UI Department of Neurosurgery; and Michael Welsh, UI professor of internal medicine and molecular physiology and biophysics and a Howard Hughes Medical Institute investigator. Buzza and Hurlemann are co-first authors on the paper.


Story Source:

The above story is reprinted from materials provided byUniversity of Iowa. The original article was written by John Riehl.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal References:

  1. Justin S Feinstein, Colin Buzza, Rene Hurlemann, Robin L Follmer, Nader S Dahdaleh, William H Coryell, Michael J Welsh, Daniel Tranel, John A Wemmie. Fear and panic in humans with bilateral amygdala damageNature Neuroscience, 2013; DOI: 10.1038/nn.3323
  2. Adam E. Ziemann, Jason E. Allen, Nader S. Dahdaleh, Iuliia I. Drebot, Matthew W. Coryell, Amanda M. Wunsch, Cynthia M. Lynch, Frank M. Faraci, Matthew A. Howard, Michael J. Welsh, John A. Wemmie. The Amygdala Is a Chemosensor that Detects Carbon Dioxide and Acidosis to Elicit Fear BehaviorCell, 2009; 139 (5): 1012 DOI: 10.1016/j.cell.2009.10.029
University of Iowa (2013, February 4). Human brain is divided on fear and panic: Different areas of brain responsible for external, internal threats. ScienceDaily. Retrieved February 5, 2013, from http://www.sciencedaily.com/releases/2013/02/130204130106.htm

Men Are from Mars Earth, Women Are from Venus Earth

Feb. 4, 2013 — For decades, popular writers have entertained readers with the premise that men and women are so psychologically dissimilar they could hail from entirely different planets. But a new study shows that it’s time for the Mars/Venus theories about the sexes to come back to Earth.

On physical characteristics, like strength (top graph), men and women fall into distinct groups with very little overlap. But for most psychological attributes, including masculine attitudes (lower graph), variability within each sex and overlap between the sexes is extensive. The physical strength graph shows statistical analysis of the scores for the National Collegiate Athletic Association’s long jump, high jump, and javelin throw competitions. The masculinity-assertiveness graph is based on self-reported measures of competitiveness, decisiveness, sense of superiority, persistence, confidence, and the ability to stand up under pressure. (Credit: University of Rochester)

From empathy and sexuality to science inclination and extroversion, statistical analysis of 122 different characteristics involving 13,301 individuals shows that men and women, by and large, do not fall into different groups. In other words, no matter how strange and inscrutable your partner may seem, their gender is probably only a small part of the problem.

“People think about the sexes as distinct categories,” says Harry Reis, professor of psychology at the University of Rochester and a co-author on the study to be published in the February issue of the Journal of Personality and Social Psychology. “‘Boy or girl?’ is the first question parents are asked about their newborn, and sex persists through life as the most pervasive characteristic used to distinguish categories among humans.”

But the handy dichotomy often falls apart under statistical scrutiny, says lead author Bobbi Carothers, who completed the study as part of her doctoral dissertation at Rochester and is now a senior data analyst for the Center for Public Health System Science at Washington University in St. Louis. For example, it is not at all unusual for men to be empathic and women to be good at math — characteristics that some research has associated with the other sex, says Carothers. “Sex is not nearly as confining a category as stereotypes and even some academic studies would have us believe,” she adds.

The authors reached that conclusion by reanalyzing data from 13 studies that had shown significant, and often large, sex differences. Reis and Carothers also collected their own data on a range of psychological indicators. They revisited surveys on relationship interdependence, intimacy, and sexuality. They reopened studies of the “big five” personality traits: extroversion, openness, agreeableness, emotional stability, and conscientiousness. They even crunched the numbers on such highly charged and seemingly defining gender characteristics as femininity and masculinity. Using three separate statistical procedures, the authors searched for evidence of attributes that could reliably categorize a person as male or female.

The pickings, it turned out, were slim. Statistically, men and women definitely fall into distinct groups, or taxons, based on anthropometric measurements such as height, shoulder breadth, arm circumference, and waist-to-hip ratio. And gender can be a reliable predictor for interest in very stereotypic activities, such as scrapbooking and cosmetics (women) and boxing and watching pornography (men).

But for the vast majority of psychological traits, including the fear of success, mate selection criteria, and empathy, men and women are definitely from the same planet. Instead of scores clustering at either end of the spectrum — the way they do with, say, height or physical strength — psychological indicators fall along a linear gradation for both genders. With very few exceptions, variability within each sex and overlap between the sexes is so extensive that the authors conclude it would be inaccurate to use personality types, attitudes, and psychological indicators as a vehicle for sorting men and women.

“Thus, contrary to the assertions of pop psychology titles like Men Are From Mars, Women Are From Venus, it is untrue that men and women think about their relationships in qualitatively different ways,” the authors write. “Even leading researchers in gender and stereotyping can fall into the same trap.”

That men and women approach their social world similarly does not imply that there are no differences in average scores between the sexes. Average differences do exist, write the authors. “The traditional and easiest way to think of gender differences is in terms of a mean difference,” Carothers and Reis write. But such differences “are not consistent or big enough to accurately diagnose group membership” and should not be misconstrued as evidence for consistent and inflexible gender categories, they conclude.

“Those who score in a stereotypic way on one measure do not necessarily do so on another,” the authors note. A man who ranks high on aggression, may also rank low on math, for example. Caution the authors: “the possession of traits associated with gender is not as simple as ‘this or that’.”

Although emphasizing inherent differences between the sexes certainly strikes a chord with many couples, such simplistic frameworks can be harmful in the context of relationships, says Reis, a leader in the field of relationship science. “When something goes wrong between partners, people often blame the other partner’s gender immediately. Having gender stereotypes hinders people from looking at their partner as an individual. They may also discourage people from pursuing certain kinds of goals. When psychological and intellectual tendencies are seen as defining characteristics, they are more likely to be assumed to be innate and immutable. Why bother to try to change?”

The best evidence we have that the so-called Mars/Venus gender division is not the true source of friction within relationships, says Reis, is that “gay and lesbian couples have much the same problems relating to each other that heterosexual couples do. Clearly, it’s not so much sex, but human character that causes difficulties.”

The findings support the “gender similarities hypothesis” put forth by University of Wisconsin psychologist Janet Hyde. Using different methods, Hyde has challenged “overinflated claims of gender differences” with meta-analyses of psychology studies, demonstrating that males and females are similar on most, though not all, psychological variables.

Those results were not a surprise for Carothers. Raised by two physical education teachers, the self-described tomboy grew up with “all kinds of sporting equipment… I did not question stereotypical attitudes, I just knew that they did not necessarily fit me and the folks I hung out with.” That experience, she says, fueled a lifelong interest into the biological basis of behavior. When she discovered in graduate school that she could apply her prowess in statistics to exploring sex differences, the project became “a marriage of two interests.”

The authors acknowledge that the study is based largely on questionnaires and may not fully capture real life actions. “Methods that more pointedly measure interpersonal behaviors (how many birthday cards have they sent this year, how many times a month do they call a friend just to see how he or she is, etc.) may more readily reveal a gender taxon,” they write.

By the same token, however, as gender roles are liberalized, the authors speculate that new studies may show even less divergence between men and women in the United States. The opposite may be the case in cultures that are far more prescriptive of male and female roles, such as Saudi Arabia, Reis and Carothers predict.

 

Story Source:

The above story is reprinted from materials provided byUniversity of Rochester.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Bobbi J. Carothers, Harry T. Reis. Men and women are from Earth: Examining the latent structure of gender..Journal of Personality and Social Psychology, 2013; 104 (2): 385 DOI: 10.1037/a0030437
University of Rochester (2013, February 4). Men are from Mars Earth, women are fromVenus Earth. ScienceDaily. Retrieved February 5, 2013, from http://www.sciencedaily.com/releases/2013/02/130204094518.htm

Pioneering Research Helps to Unravel the Brain’s Vision Secrets

Feb. 3, 2013 — A new study led by scientists at the Universities of York and Bradford has identified the two areas of the brain responsible for our perception of orientation and shape.


 

Using sophisticated imaging equipment at York Neuroimaging Centre (YNiC), the research found that the two neighbouring areas of the cortex — each about the size of a 5p coin and known as human visual field maps — process the different types of visual information independently.

The scientists, from the Department of Psychology at York and the Bradford School of Optometry & Vision Science established how the two areas worked by subjecting them to magnetic fields for a short period which disrupted their normal brain activity. The research which is reported in Nature Neuroscience represents an important step forward in understanding how the brain processes visual information.

Attention now switches to a further four areas of the extra-striate cortex which are also responsible for visual function but whose specific individual roles are unknown.

The study was designed by Professor Tony Morland, of York’s Department of Psychology and the Hull York Medical School, and Dr Declan McKeefry, of the Bradford School of Optometry and Vision Science at the University of Bradford. It was undertaken as part of a PhD by Edward Silson at York.

Researchers used functional magnetic resonance imaging (fMRI) equipment at YNiC to pinpoint the two brain areas, which they subsequently targeted with magnetic fields that temporarily disrupt neural activity. They found that one area had a specialised and causal role in processing orientation while neural activity in the other underpinned the processing of shape defined by differences in curvature.

Professor Morland said: “Measuring activity across the brain with FMRI can’t tell us what causal role different areas play in our perception. It is by disrupting brain function in specific areas that allows the causal role of that area to be assessed.

“Historically, neuropsychologists have found out a lot about the human brain by examining people who have had permanent disruption of certain parts of the brain because of injury to it. Unfortunately, brain damage seldom occurs at the spatial scale that allows the function of small neighbouring areas to be understood. Our approach is to temporarily disrupt brain activity by applying brief magnetic fields. When these fields are applied to one, small area of the brain, we find that orientation tasks are harder, while disrupting activity in this area’s nearest neighbour only affected the ability to perceive shapes.”

Dr McKeefry added: “The combination of modern brain scanning technology along with magnetic neuro-stimulation techniques provides us with a powerful means by which we can study the workings of the living human brain.

“The results that we report in this paper provide new insights into how the human brain embarks upon the complex task of analysing objects that we see in the world around us.

“Our work demonstrates how processing of different aspects of visual objects, such as orientation and shape, occurs in different brain areas that lie side by side. The ultimate challenge will be to reveal how this information is combined across these and other brain areas and how it ultimately leads to object recognition.”


Story Source:

The above story is reprinted from materials provided byUniversity of York, via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Edward H Silson, Declan J McKeefry, Jessica Rodgers, Andre D Gouws, Mark Hymers & Antony B Morland.Specialized and independent processing of orientation and shape in visual field maps LO1 and LO2Nature Neuroscience, 2013 DOI: 10.1038/nn.3327
University of York (2013, February 3). Pioneering research helps to unravel the brain’s vision secrets. ScienceDaily. Retrieved February 4, 2013, from http://www.sciencedaily.com/releases/2013/02/130203145511.htm