Laser light rewrites memories in mice

With a burst of light, scientists can change good mouse memories into bad ones, and bad ones into good. The results, published August 27 in Nature, underscore how memories are not written in stone, and bring scientists closer to understanding how nerve cells in the brain create and store memories.

The study provides a “much more precise handle on some of the steps of memory formation than we’ve had before,” says neuroscientist Richard Morris of the University of Edinburgh. One day, such knowledge may lead to treatments for people who struggle with unwanted negative memori

Stop and listen: Study shows how movement affects hearing

Date:

August 27, 2014

Source:

Duke University

Summary:

When we want to listen carefully to someone, the first thing we do is stop talking. The second thing we do is stop moving altogether. The interplay between movement and hearing has a counterpart deep in the brain. A new study used optogenetics to reveal exactly how the motor cortex, which controls movement, can tweak the volume control in the auditory cortex, which interprets sound.

Neurons in the mouse motor cortex (green) project to the auditory cortex. As the mouse moves, these neurons suppress activity in the auditory cortex.

When we want to listen carefully to someone, the first thing we do is stop talking. The second thing we do is stop moving altogether. This strategy helps us hear better by preventing unwanted sounds generated by our own movements.

This interplay between movement and hearing also has a counterpart deep in the brain. Indeed, indirect evidence has long suggested that the brain's motor cortex, which controls movement, somehow influences the auditory cortex, which gives rise to our conscious perception of sound.

A new Duke study, appearing online August 27 inNature, combines cutting-edge methods in electrophysiology, optogenetics and behavioral analysis to reveal exactly how the motor cortex, seemingly in anticipation of movement, can tweak the volume control in the auditory cortex.

The new lab methods allowed the group to "get beyond a century's worth of very powerful but largely correlative observations, and develop a new, and really a harder, causality-driven view of how the brain works," said the study's senior author Richard Mooney Ph.D., a professor of neurobiology at Duke University School of Medicine, and a member of the Duke Institute for Brain Sciences.

The findings contribute to the basic knowledge of how communication between the brain's motor and auditory cortexes might affect hearing during speech or musical performance. Disruptions to the same circuitry may give rise to auditory hallucinations in people with schizophrenia.

In 2013, researchers led by Mooney first characterized the connections between motor and auditory areas in mouse brain slices as well as in anesthetized mice. The new study answers the critical question of how those connections operate in an awake, moving mouse.

"This is a major step forward in that we've now interrogated the system in an animal that's freely behaving," said David Schneider, a postdoctoral associate in Mooney's lab.

Mooney suspects that the motor cortex learns how to mute responses in the auditory cortex to sounds that are expected to arise from one's own movements while heightening sensitivity to other, unexpected sounds. The group is testing this idea.

"Our first step will be to start making more realistic situations where the animal needs to ignore the sounds that its movements are making in order to detect things that are happening in the world," Schneider said.

In the latest study, the team recorded electrical activity of individual neurons in the brain's auditory cortex. Whenever the mice moved -- walking, grooming, or making high-pitched squeaks -- neurons in their auditory cortex were dampened in response to tones played to the animals, compared to when they were at rest.

To find out whether movement was directly influencing the auditory cortex, researchers conducted a series of experiments in awake animals using optogenetics, a powerful method that uses light to control the activity of select populations of neurons that have been genetically sensitized to light. Like the game of telephone, sounds that enter the ear pass through six or more relays in the brain before reaching the auditory cortex.

"Optogenetics can be used to activate a specific relay in the network, in this case the penultimate node that relays signals to the auditory cortex," Mooney said.

About half of the suppression during movement was found to originate within the auditory cortex itself. "That says a lot of modulation is going on in the auditory cortex, and not just at earlier relays in the auditory system" Mooney said.

More specifically, the team found that movement stimulates inhibitory neurons that in turn suppress the response of the auditory cortex to tones.

The researchers then wondered what turns on the inhibitory neurons. The suspects were many. "The auditory cortex is like this giant switching station where all these different inputs come through and say, 'Okay, I want to have access to these interneurons,' " Mooney said. "The question we wanted to answer is who gets access to them during movement?"

The team knew from previous experiments that neuronal projections from the secondary motor cortex (M2) modulate the auditory cortex. But to isolate M2's relative contribution -- something not possible with traditional electrophysiology -- the researchers again used optogenetics, this time to switch on and off the M2's inputs to the inhibitory neurons.

Turning on M2 inputs reproduced a sense of movement in the auditory cortex, even in mice that were resting, the group found. "We were sending a 'Hey I'm moving' signal to the auditory cortex," Schneider said. Then the effect of playing a tone on the auditory cortex was much the same as if the animal had actually been moving -- a result that confirmed the importance of M2 in modulating the auditory cortex. On the other hand, turning off M2 simulated rest in the auditory cortex, even when the animals were still moving.

"I couldn't contain my excitement when we first saw that result," said Anders Nelson, a neurobiology graduate student in Mooney's group.

Rubber meets the road with new carbon, battery technologies

Date:

August 27, 2014

Source:

Oak Ridge National Laboratory

Summary:

Recycled tires could see new life in lithium-ion batteries that provide power to plug-in electric vehicles and store energy produced by wind and solar, say researchers. By modifying the microstructural characteristics of carbon black, a substance recovered from discarded tires, a team is developing a better anode for lithium-ion batteries.

ORNL researchers’ goal is to scale up the recovery process and demonstrate applications as anodes for lithium-ion batteries in large-format pouch cells.

Recycled tires could see new life in lithium-ion batteries that provide power to plug-in electric vehicles and store energy produced by wind and solar, say researchers at the Department of Energy’s Oak Ridge National Laboratory.

By modifying the microstructural characteristics of carbon black, a substance recovered from discarded tires, a team led by Parans Paranthaman and Amit Naskar is developing a better anode for lithium-ion batteries. An anode is a negatively charged electrode used as a host for storing lithium during charging.

The method, outlined in a paper published in the journal RSC Advances, has numerous advantages over conventional approaches to making anodes for lithium-ion batteries.

“Using waste tires for products such as energy storage is very attractive not only from the carbon materials recovery perspective but also for controlling environmental hazards caused by waste tire stock piles,” Paranthaman said.

The ORNL technique uses a proprietary pretreatment to recover pyrolytic carbon black material, which is similar to graphite but man-made. When used in anodes of lithium-ion batteries, researchers produced a small, laboratory-scale battery with a reversible capacity that is higher than what is possible with commercial graphite materials.

In fact, after 100 cycles the capacity measures nearly 390 milliamp hours per gram of carbon anode, which exceeds the best properties of commercial graphite. Researchers attribute this to the unique microstructure of the tire-derived carbon.

“This kind of performance is highly encouraging, especially in light of the fact that the global battery market for vehicles and military applications is approaching $78 billion and the materials market is expected to hit $11 billion in 2018,” Paranthaman said.

Anodes are one of the leading battery components, with 11 to 15 percent of the materials market share, according to Naskar, who noted that the new method could eliminate a number of hurdles.

“This technology addresses the need to develop an inexpensive, environmentally benign carbon composite anode material with high-surface area, higher-rate capability and long-term stability,” Naskar said.

Encyclopedia of how genomes function gets much bigger

Date:

August 27, 2014

Source:

DOE/Lawrence Berkeley National Laboratory

Summary:

A big step in understanding the mysteries of the human genome has been unveiled in the form of three analyses that provide the most detailed comparison yet of how the genomes of the fruit fly, roundworm, and human function. The analyses will likely offer insights into how the information in the human genome regulates development, and how it is responsible for diseases.

Berkeley Lab scientists contributed to an NHGRI effort that provides the most detailed comparison yet of how the genomes of the fruit fly, roundworm, and human function.

A Big step in understanding the mysteries of the human genome was unveiled today in the form of three analyses that provide the most detailed comparison yet of how the genomes of the fruit fly, roundworm, and human function.

 

The research, appearing August 28 in in the journal Nature, compares how the information encoded in the three species' genomes is "read out," and how their DNA and proteins are organized into chromosomes.

The results add billions of entries to a publicly available archive of functional genomic data. Scientists can use this resource to discover common features that apply to all organisms. These fundamental principles will likely offer insights into how the information in the human genome regulates development, and how it is responsible for diseases.

The analyses were conducted by two consortia of scientists that include researchers from the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab). Both efforts were funded by the National Institutes of Health's National Human Genome Research Institute.

One of the consortiums, the "model organism Encyclopedia of DNA Elements" (modENCODE) project, catalogued the functional genomic elements in the fruit fly and roundworm. Susan Celniker and Gary Karpen of Berkeley Lab's Life Sciences Division led two fruit fly research groups in this consortium. Ben Brown, also with the Life Sciences Division, participated in another consortium, ENCODE, to identify the functional elements in the human genome.

The consortia are addressing one of the big questions in biology today: now that the human genome and many other genomes have been sequenced, how does the information encoded in an organism's genome make an organism what it is? To find out, scientists have for the past several years studied the genomes of model organisms such as the fruit fly and roundworm, which are smaller than our genome, yet have many genes and biological pathways in common with humans. This research has led to a better understanding of human gene function, development, and disease.

Comparing transcriptomes

In all organisms, the information encoded in genomes is transcribed into RNA molecules that are either translated into proteins, or utilized to perform functions in the cell. The collection of RNA molecules expressed in a cell is known as its transcriptome, which can be thought of as the "read out" of the genome.

In the research announced today, dozens of scientists from several institutions looked for similarities and differences in the transcriptomes of human, roundworm, and fruit fly. They used deep sequencing technology and bioinformatics to generate large amounts of matched RNA-sequencing data for the three species. This involved 575 experiments that produced more than 67 billion sequence reads.

A team led by Celniker, with help from Brown and scientists from several other labs, conducted the fruit fly portion of this research. They mapped the organism's transcriptome at 30 time points of its development. They also explored how environmental perturbations such as heavy metals, herbicides, caffeine, alcohol and temperature affect the fly's transcriptome. The result is the finest time-resolution analysis of the fly genome's "read out" to date -- and a mountain of new data.

"We went from two billion reads in research we published in 2011, to 20 billion reads today," says Celniker. "As a result, we found that the transcriptome is much more extensive and complex than previously thought. It has more long non-coding RNAs and more promoters."

When the scientists compared transcriptome data from all three species, they discovered 16 gene-expression modules corresponding to processes such as transcription and cell division that are conserved in the three animals. They also found a similar pattern of gene expression at an early stage of embryonic development in all three organisms.

This work is described in a Nature article entitled "Comparative analysis of the transcriptome across distant species."

Comparing chromatin

Another group, also consisting of dozens of scientists from several institutions, analyzed chromatin, which is the combination of DNA and proteins that organize an organism's genome into chromosomes. Chromatin influences nearly every aspect of genome function.

Karpen led the fruit fly portion of this work, with Harvard Medical School's Peter Park contributing on the bioinformatics side, and scientists from several other labs also participating. The team mapped the distribution of chromatin proteins in the fruit fly genome. They also learned how chemical modifications to chromatin proteins impact genome functions.

Their results were compared with results from human and roundworm chromatin research. In all, the group generated 800 new chromatin datasets from different cell lines and developmental stages of the three species, bringing the total number of datasets to more than 1400. These datasets are presented in a Nature article entitled "Comparative analysis of metazoan chromatin organization."

Here again, the scientists found many conserved chromatin features among the three organisms. They also found significant differences, such as in the composition and locations of repressive chromatin.

But perhaps the biggest scientific dividend is the data itself.

"We found many insights that need follow-up," says Karpen. "And we've also greatly increased the amount of data that others can access. These datasets and analyses will provide a rich resource for comparative and species-specific investigations of how genomes, including the human genome, function."

First study of brain activation in MS using fNIRS

Date:

August 27, 2014

Source:

Kessler Foundation

Summary:

Using functional near infrared spectroscopy, researchers showed differential brain activation patterns between people with multiple sclerosis (MS) and healthy controls. This is first MS study to examine brain activation using fNIRS during a cognitive task.

Using functional near infrared spectroscopy (fNIRS), Kessler Foundation researchers have shown differential brain activation patterns between people with multiple sclerosis (MS) and healthy controls. This is the first MS study in which brain activation was studied using fNIRS while participants performed a cognitive task. The article, "Neuroimaging and cognition using functional near infrared spectroscopy (fNIRS) in multiple sclerosis," was published online on June 11 by Brain Imaging and Behavior. Authors are Jelena Stojanovic-Radic, PhD, Glenn Wylie, DPhil, Gerald Voelbel, PhD, Nancy Chiaravalloti, PhD, and John DeLuca, PhD.

Researchers compared 13 individuals with MS with 12 controls for their performance on a working memory task with four levels of difficulty. Most such studies have employed functional magnetic resonance imaging (fMRI); fNIRS has been used infrequently in clinical populations, and has not been applied previously to neuroimaging research in MS. Studies comparing fMRI findings with those of fNIRS, however, show broad agreement in terms of activation patterns.

Results showed differences in activation between the groups that were dependent on task load. The MS group had an increase in activation at low task difficulty and a decrease in activation at high task difficulty. Conversely, in the control group, activation decreased with low task difficulty and increased with high task difficulty. Performance accuracy was lower in the MS group for low task load; there were no differences between the groups at the higher task loads.

"The data we obtained via fNIRS are consistent with fMRI data for clinical populations. We demonstrated that fNIRS is capable of detecting neuronal activation with a reasonable degree of detail," noted Glenn Wylie, DPhil, associate director of Neuroscience and the Neuroimaging Center at Kessler Foundation. "We attribute the differences in brain activation patterns to the effort expended during the working memory task rather than to differences in speed of processing," he added. "Because fNIRS is more portable and easier to use that fMRI, it may offer advantages in monitoring cognitive interventions that require frequent scans."

In addition to working memory, future research in clinical populations should focus on processing speed and episodic memory, cognitive functions that are also affected in MS.

Fear, Safety and the Role of Sleep in Human PTSD

 Fragmented REM sleep may hinder effective treatment of mental health condition

The effectiveness of post-traumatic stress disorder (PTSD) treatment may hinge significantly upon sleep quality, report researchers at the University of California, San Diego School of Medicine and Veterans Affairs San Diego Healthcare System in a paper published today in the Journal of Neuroscience.

“I think these findings help us understand why sleep disturbances and nightmares are such important symptoms in PTSD,” said Sean P.A. Drummond, PhD, professor of psychiatry and director of the Behavioral Sleep Medicine Program at the VA San Diego Healthcare System. “Our study suggests the physiological mechanism whereby sleep difficulties can help maintain PTSD. It also strongly implies a mechanism by which poor sleep may impair the ability of an individual to fully benefit from exposure-based PTSD treatments, which are the gold standard of interventions.

“The implication is that we should try treating sleep before treating the daytime symptoms of PTSD and see if those who are sleeping better when they start exposure therapy derive more benefit.”

PTSD is an often difficult-to-treat mental health condition triggered by a terrifying event. It is frequently associated with persons who have served in war zones and is characterized by severe anxiety, flashbacks, nightmares and uncontrollable thoughts, often fearful. Research has shown that fear conditioning, considered an animal model of PTSD, results in disruption of animals’ rapid eye movement (REM) sleep – periods of deeper, dream-filled slumber. Fear conditioning is a form of learning in which the animal model is trained to associate an aversive stimulus, such as an electrical shock, with a neutral stimulus, such as a tone or beep.

Drummond and colleagues investigated the impact of fear conditioning – and another form of behavioral training called safety signal learning – upon human REM sleep, using 42 healthy volunteers tested over three consecutive days and nights. Safety signals are learned cues that predict the non-occurrence of an aversive event.

“We examined the relationship between REM sleep and the ability to learn – and consolidate memory for – stimuli that represent threats and that represent safety,” said Drummond.

“In PTSD, humans learn to associate threat with a stimulus that used to be neutral or even pleasant. Often, this fear generalizes so that they have a hard time learning that other stimuli are safe. For example, a U.S. Marine in Iraq might suffer trauma when her personnel carrier is blown up by road side bomb hidden in trash alongside the road. When she comes home, she should learn that trash on the side of I-5 does not pose a threat – it’s a safe stimulus – but that may be difficult for her.”

The researchers found that increased safety signaling was associated with increased REM sleep consolidation at night and that the quality of overnight REM sleep was related to how well volunteers managed fear conditioning.

Drummond said stimuli representing safety increased human REM sleep and that “helps humans distinguish threatening stimuli from safe stimuli the next day. So while animal studies focused on learning and unlearning a threat, our study showed REM sleep in humans is more related to learning and remembering safety.”

He noted, however, that the findings are not conclusive. No comparable animal studies, for example, have examined the relationship between safety and REM sleep. Nonetheless, the findings do encourage further investigation, eventually into human PTSD populations where fear, safety and sleep are on-going and paramount concerns among military veterans and others.

“A very large percentage of missions in both Iraq and Afghanistan were at night,” said Drummond, who is also associate director of the Mood Disorders Psychotherapy Program at VA San Diego Healthcare System. “So soldiers learned the night was a time of danger. When they come home, they have a hard time learning night here is a time to relax and go to sleep.”

Co-authors include Anisa J. Marshall, VA San Diego Healthcare System; Dean T. Acheson and Victoria B. Risbrough, VA San Diego Healthcare System and Department of Psychiatry, UCSD; and Laura D. Straus, VA San Diego Healthcare System and SDSU-UCSD Joint Doctoral Program in Clinical Psychology.

Funding support came, in part, from the Defense Medical Research and Development Program (DM102425). Infrastructure support provided by VA San Diego Center for Excellence in Stress and Mental Health.

 

Finding Keys to Glioblastoma Therapeutic Resistance

Researchers at the University of California, San Diego School of Medicine have found one of the keys to why certain glioblastomas – the primary form of a deadly brain cancer – are resistant to drug therapy. The answer lies not in the DNA sequence of the tumor, but in its epigenetic signature. These findings have been published online as a priority report in the journal Oncotarget.

“There is a growing interest to guide cancer therapy by sequencing the DNA of the cancer cell,” said Clark Chen, MD, PhD, vice-chairman of Research and Academic Development, UC San Diego Division of Neurosurgery and the principal investigator of the study. “Our study demonstrates that the sensitivity of glioblastoma to a drug is influenced not only by the content of its DNA sequences, but also by how the DNA sequences are organized and interpreted by the cell.”

The team of scientists, led by Chen, used a method called comparative gene signature analysis to study the genetic profiles of tumor specimens collected from approximately 900 glioblastoma patients. The method allows investigators to discriminate whether specific cellular processes are “turned on” or “turned off” in glioblastomas. “Our study showed that not all glioblastomas are the same. We were able to classify glioblastomas based on the type of cellular processes that the cancer cells used to drive tumor growth,” said Jie Li, PhD, senior postdoctoral researcher in the Center for Theoretical and Applied Neuro-Oncology at UC San Diego and co-first author of the paper.

One of these cellular processes involves Epidermal Growth Factor Receptor (EGFR). The study revealed that EGFR signaling is suppressed in a subset of glioblastomas. Importantly, this suppression is not the result of altered DNA sequences or mutations. Instead, EGFR is turned off as a result of how the DNA encoding the EGFR gene is organized in the cancer cell. This form of regulation is termed “epigenetic.” Because EGFR is turned off in these glioblastomas, they become insensitive to drugs designed to inhibit EGFR signaling.

“Our research suggests that the selection of appropriate therapies for our brain tumor patients will require a meaningful synthesis of genetic and epigenetic information derived from the cancer cell,” said co-first author Zachary J. Taich.

Co-authors include Amit Goyal, David Gonda, Johnny Akers, Bandita Adhikari, Kunal Patel and Bob S. Carter, Center for Theoretic and Applied Neuro-Oncology, UCSD; Scott Vandenberg, Department of Pathology, UCSD; Wei Yan, Zhaoshi Bao and Tao Jiang, Department of Neurosurgery, UCSD; Renzhi Wang, Peking Union Medical College Hospital, China; and Ying Mao, Huashan Hospital, Shanghai Medical College, Fudan University, China.

Funding for this research came, in part, from  the Sontag Foundation, the Burroughs Wellcome Foundation, the Kimmel Foundation, the Doris Duke Foundation and the Forbeck Foundation.

Is proposed college rating systems unfair to low-income, minority students?

In an effort to address recent accountability and financial aid policy proposals in Washington that may be detrimental to low-income and minority students, a higher education research and policy briefing will take place Sept. 2, 9 a.m.–noon. Stella Flores, associate professor at Vanderbilt University’s Peabody College of education and human development, will be a member of a panel of education researchers who will discuss recent research related to these issues.

“Do Higher Ed Accountability Proposals Narrow Opportunity For Minority Students and Minority-Serving Institutions? What New Research Tells Us,” will convene at the U.S. Capitol Visitors Center, Congressional Auditorium and Atrium.

Flores is lead investigator of a new study that sheds light on the role of pre-college factors on college completion at Minority Serving Institutions, will discuss how racial gaps in college completion rates are associated with both the pre-college characteristics of students and the institutional characteristics of the colleges and universities they attend.

The briefing is open to congressional staff, policymakers, advocates, researchers and the press. It is hosted by The Civil Rights Project at UCLA. Moderating will be Gary Orfield, a Distinguished Research Professor of Education, Law, Political Science, and Urban Planning at UCLA, and co-director of the CRP.

Additional panelists will include Marybeth Gasman (University of Pennsylvania); Sara Goldrick-Rab (University of Wisconsin–Madison); Sylvia Hurtado (UCLA); Nicholas Hillman (University of Wisconsin–Madison); Willie Kirkland (Dillard University); and Anne-Marie Nuñez (University of Texas-San Antonio).

This briefing is supported by The Ford Foundation. Additional support is provided by the Graduate School of Education at Penn State, The Center for MSIs, Wisconsin Hope Lab, the Center for Access, Equity, and Diversity at Vanderbilt University, UNCF, Excelencia in Education, and the American Council on Education/Center for Policy Research and Strategy.

Coal’s continued dominance of global industrialization must be made more vivid in climate change accounting

The world’s accounting system for carbon emissions, run by the United Nations, disregards capital investments in future coal-fired and natural-gas power plants that will commit the world to several decades and billions of tons of greenhouse gas emissions, according to a new study from Princeton University and the University of California-Irvine published Aug. 26 in the journal Environmental Research Letters.

In the paper, Robert Socolow, a Princeton professor, emeritus, of mechanical and aerospace engineering, and co-author Steven Davis, a professor of earth system science at the UC-Irvine, develop a “commitment accounting” that assigns all the future emissions of a facility to the year when it begins working. This method reveals that the fossil-fuel-burning power plants built worldwide in 2012 alone will produce roughly 19 billion tons of the global-warming gas carbon dioxide (CO2) over their lifetime, assuming the plants operate for 40 years. This is considerably more than the 14 billion tons of CO2 emissions produced by all the plants operating worldwide in 2012.

“We are flying a plane that is missing a crucial dial on the instrument panel,” Socolow said. “The needed dial would report committed emissions. Right now, as far as emissions are concerned, the only dial on our plane tells us about current emissions, not the emissions that current capital investments will bring about in future years.”

Further findings from the study show that the plants that were operating around the world in 2012, before they are shut down, will emit more than 300 billion tons of CO2. The number of new power plants is rapidly growing and very few old ones are being retired. In fact, total remaining commitments in the global power sector have not declined in a single year since 1950. These commitments grew at an average rate of 4 percent per year between 2000 and 2012.

he authors report that the increases in global commitments reflect the rapid expansion of China’s power sector since 1995, as well as new power plants built in developing countries such as India, Indonesia, Saudi Arabia and Iran. Plants in China and India now respectively represent 42 percent and 8 percent of committed future emissions, while plants operating in the United States and Europe represent roughly 11 percent and 9 percent, respectively. The share of commitments related to natural gas-fired plants has increased from roughly 15 percent in 1980 to 27 percent in 2012, but aside from the Middle East, almost the entire developing world is relying on coal for its industrialization.

“A high-carbon future is being locked in by the world’s capital investments in power plants and other infrastructure,” Socolow said. “Finding paths to low-carbon industrialization must become a global priority.”

“Without commitment accounting, we are like the dieter who makes a pledge to eat better while buying 20 gallons of rich ice cream and a new freezer,” said David Hawkins, director of Climate Programs at the Natural Resources Defense Council.

“By revealing the emissions that are anticipated decades into the future, commitment accounting may help to integrate analyses of capital investment, cumulative emissions and damages from climate warming,” Davis said.

Trash burning worldwide significantly worsens air pollution

Unregulated trash burning around the globe is pumping far more pollution into the atmosphere than shown by official records. A new study led by the National Center for Atmospheric Research estimates that more than 40 percent of the world’s garbage is burned in such fires, emitting gases and particles that can substantially affect human health and climate change.

The new study provides the first rough estimates, on a country-by-country basis, of pollutants such as particulates, carbon monoxide, and mercury that are emitted by the fires. Such pollutants have been linked to serious medical issues.

The researchers also estimated emissions of carbon dioxide, the most common greenhouse gas produced by human activity.

Unlike emissions from commercial incinerators, the emissions from burning trash in open fires often go unreported to environmental agencies and are left out of many national inventories of air pollution. For that reason, they are not incorporated into policy making.

“Air pollution across much of the globe is significantly underestimated because no one is tracking open-fire burning of trash,” said NCAR scientist Christine Wiedinmyer, lead author of the new study. “The uncontrolled burning of trash is a major source of pollutants, and it’s one that should receive more attention.”

Quantifying the extent of burning trash may change how policy makers track emissions, as well as how scientists incorporate air pollution into computer models used to study the atmosphere.

Because trash burning is unregulated and unmonitored, Wiedinmyer said that actual emissions could be larger or smaller than the study’s estimates by a factor of two. Still, the analysis represents the most comprehensive effort to date to account for emissions from trash burning.

The new study, published in Environmental Science & Technology, was funded by the National Science Foundation, which is NCAR’s sponsor. It was co-authored by scientists from the University of Montana and the U.S. Environmental Protection Agency who were also involved in measuring the composition of trash-burning emissions.

Shrouded in smoke

Trash burning is a global phenomenon. But it is most prevalent in developing countries where there are fewer trash disposal facilities, such as landfills and incinerators.

The amount of garbage burned in remote villages and crowded megacities is likely on the rise, as more people worldwide are consuming more goods. The trash often contains discarded plastics and electronics as well as traditional materials such as food scraps and wood.

Wiedinmyer began wondering about the impact of burning trash while visiting remote villages in Ghana. The villages were shrouded in smoke caused in part from trash fires that smoldered all day.

To estimate emissions from trash fires, Wiedinmyer and her co-authors compared population figures and per capita waste production with official tallies of trash disposal for each country in the world. They estimated that 1.1 billion tons (1 billion metric tons), or 41 percent, of the total waste generated worldwide is disposed of through unregulated burning every year.

The countries that produce the most total waste, according to the study’s methods, are heavily populated countries with various levels of industrial development: China, the United States, India, Japan, Brazil, and Germany. But the study concluded that the nations with the greatest emissions from trash burning are populous developing countries: China, India, Brazil, Mexico, Pakistan, and Turkey.

By analyzing consumption patterns in each country, the research team then estimated the type and amount of pollutants from the fires.

The study concluded that as much as 29 percent of human-related global emissions of small particulates (less than 2.5 microns in diameter) come from the fires, as well as 10 percent of mercury and 40 percent of a group of gases known as polycyclic aromatic hydrocarbons (PAHs). These pollutants have been linked to such significant health impacts as decreased lung function, neurological disorders, cancer, and heart attacks.

Trash burning in some countries accounts for particularly high quantities of certain types of pollutants. In China, for example, 22 percent of larger particles (those up to 10 microns in diameter) come from burning garbage.

The global impact on greenhouse gas emissions appears to be less, though still significant, with burning trash producing an estimated 5 percent of human-related carbon dioxide emissions. (By comparison, the Kyoto Protocol strove for a global 5 percent cut in greenhouse-gas emissions from industrialized countries.) In certain developing countries—such as Lesotho, Burundi, Mali, Somalia, and Sri Lanka—the trash burning produces more carbon dioxide than is tallied in official inventories. This discrepancy can be important in international negotiations over reducing greenhouse gas emissions.

Wiedinmyer said the next step in her research will be to track the pollutants to determine where they are having the greatest impacts.

“This study was a first step to put some bounds on the magnitude of this issue,” she said. “The next step is to look at what happens when these pollutants are e

Insect diet helped early humans build bigger brains, study suggests

Quest for elusive bugs spurred primate tool use, problem-solving skills

Figuring out how to survive on a lean-season diet of hard-to-reach ants, slugs and other bugs may have spurred the development of bigger brains and higher-level cognitive functions in the ancestors of humans and other primates, suggests research from Washington University in St. Louis.

“Challenges associated with finding food have long been recognized as important in shaping evolution of the brain and cognition in primates, including humans,” said Amanda D. Melin, PhD, assistant professor of anthropology in Arts & Sciences and lead author of the study.

“Our work suggests that digging for insects when food was scarce may have contributed to hominid cognitive evolution and set the stage for advanced tool use.”

Based on a five-year study of capuchin monkeys in Costa Rica, the research provides support for an evolutionary theory that links the development of sensorimotor (SMI) skills, such as increased manual dexterity, tool use, and innovative problem solving, to the creative challenges of foraging for insects and other foods that are buried, embedded or otherwise hard to procure.

Published in the June 2014 Journal of Human Evolution, the study is the first to provide detailed evidence from the field on how seasonal changes in food supplies influence the foraging patterns of wild capuchin monkeys.

The study is co-authored by biologist Hilary C. Young and anthropologists Krisztina N. Mosdossy and Linda M. Fedigan, all from the University of Calgary, Canada.

It notes that many human populations also eat embedded insects on a seasonal basis and suggests that this practice played a key role in human evolution.

“We find that capuchin monkeys eat embedded insects year-round but intensify their feeding seasonally, during the time that their preferred food – ripe fruit – is less abundant,” Melin said. “These results suggest embedded insects are an important fallback food.”

Previous research has shown that fallback foods help shape the evolution of primate body forms, including the development of strong jaws, thick teeth and specialized digestive systems in primates whose fallback diets rely mainly on vegetation.

This study suggests that fallback foods can also play an important role in shaping brain evolution among primates that fall back on insect-based diets, and that this influence is most pronounced among primates that evolve in habitats with wide seasonal variations, such as the wet-dry cycles found in some South American forests.

“Capuchin monkeys are excellent models for examining evolution of brain size and intelligence for their small body size, they have impressively large brains,” Melin said. “Accessing hidden and well-protected insects living in tree branches and under bark is a cognitively demanding task, but provides a high-quality reward: fat and protein, which is needed to fuel big brains.”

But when it comes to using tools, not all capuchin monkey strains and lineages are created equal, and Melin’s theories may explain why.

Perhaps the most notable difference between the robust (tufted, genus Sapajus) and gracile (untufted, genus Cebus) capuchin lineages is their variation in tool use. While Cebus monkeys are known for clever food-foraging tricks, such as banging snails or fruits against branches, they can’t hold a stick to their Sapajus cousins when it comes to the
innovative use and modification of sophisticated tools.

One explanation, Melin said, is that Cebus capuchins have historically and consistently occupied tropical rainforests, whereas the Sapajus lineage spread from their origins in the Atlantic rainforest into drier, more temperate and seasonal habitat types.

“Primates who extract foods in the most seasonal environments are expected to experience the strongest selection in the ‘sensorimotor intelligence’ domain, which includes cognition related to object handling,” Melin said. “This may explain the occurrence of
tool use in some capuchin lineages, but not in others.”

Genetic analysis of mitochondial chromosomes suggests that the Sapajus-Cebus diversification occurred millions of years ago in the late Miocene epoch.

“We predict that the last common ancestor of Cebus and Sapajus had a level of SMI more closely resembling extant Cebus monkeys, and that further expansion of SMI evolved in the robust lineage to facilitate increased access to varied embedded fallback foods,
necessitated by more intense periods of fruit shortage,” she said.

One of the more compelling modern examples of this behavior, said Melin, is the seasonal consumption of termites by chimpanzees, whose use of tools to extract this protein-rich food source is an important survival technique in harsh environments.

What does this all mean for hominids?

While it’s hard to decipher the extent of seasonal dietary variations from the fossil record, stable isotope analyses indicate seasonal variation in diet for at least one South African hominin, Paranthropus robustus. Other isotopic research suggests that early human diets may have included a range of extractable foods, such as termites, plant roots and tubers.

Modern humans frequently consume insects, which are seasonally important when other animal foods are limited.

This study suggests that the ingenuity required to survive on a diet of elusive insects has been a key factor in the development of uniquely human skills:

It may well have been bugs that helped build our brains.

Chimp Intelligence ‘Runs In Families,’ Environment Less Important

A chimpanzee’s intelligence is largely determined by its genes, while environmental factors may be less important than scientists previously thought, according to a Georgia State University research study.

The study found that some, but not all, cognitive, or mental, abilities, in chimpanzees depend significantly on the genes they inherit. The findings are reported in the latest issue of Current Biology.

“Intelligence runs in families,” said Dr. William Hopkins, professor in the Center for Behavioral Neuroscience at Georgia State and research scientist in the Yerkes National Primate Research Center at Emory University. “The suggestion here is that genes play a really important role in their performance on tasks while non-genetic factors didn’t seem to explain a lot. So that’s new.”

The role of genes in human intelligence or IQ has been studied for years, but Hopkins’ study is among the first to address heritability in cognitive abilities in nonhuman primates. Studies have shown that human intelligence is inherited through genes, but social and environmental factors, such as formal education and socioeconomic status, also play a role and are somewhat confounded with genetic factors. Chimpanzees, which are highly intelligent and genetically similar to humans, do not have these additional socio-cultural influences.

“Chimps offer a really simple way of thinking about how genes might influence intelligence without, in essence, the baggage of these other mechanisms that are confounded with genes in research on human intelligence,” Hopkins said.

The study involved 99 chimpanzees, ranging in age from 9 to 54, who completed 13 cognitive tasks designed to test a variety of abilities. Hopkins used quantitative genetics analysis to link the degree of relatedness between the chimpanzees to their similarities or differences in performance on the various cognitive measures to determine whether cognitive performance is inherited in chimpanzees.

Genes were found to play a role in overall cognitive abilities, as well as the performance on tasks in several categories.

Traditionally, researchers studying animal intelligence or animal learning have shared the view that environment and how previous behavior is reinforced affect how animals perform on a particular task.

“In our case, at least, it suggests that purely environmental explanations don’t really seem to tell the whole story,” Hopkins said. “Genes matter as well.”

Hopkins also studied the structure of chimpanzee intelligence to determine whether there were any similarities to the structure of human intelligence.

“We wanted to see if we gave a sample of chimpanzees a large array of tasks,” he said, “would we find essentially some organization in their abilities that made sense. The bottom line is that chimp intelligence looks somewhat like the structure of human intelligence.”

In the future, Hopkins wants to continue the study with an expanded sample size. He would also like to pursue studies to determine which genes are involved in intelligence and various cognitive abilities as well as how genes are linked to variation in the organization of the brain.

Hopkins also would like to determine which genes changed in human evolution that allowed humans to have such advanced intelligence.