Following the people and events that make up the research community at Duke

Category: Lecture Page 1 of 16

Polymath Mae Jemison encourages bolder exploration, collaboration

Photo from Biography.com

“I don’t believe that [going to] Mars pushes us hard enough.” This was just one of the bold, thought-provoking statements made by Dr. Mae Jemison, who came to speak at Duke on Monday, February 24 as part of the 15th annual Jean Fox O’Barr Distinguished Speaker Series, presented by Baldwin Scholars.

Dr. Jemison is at the pinnacle of interdisciplinary engagement—though she is most famous for serving as a NASA astronaut and being the first African American woman to go into space, she is also trained as an engineer, social scientist and dancer. Dr. Jemison always knew that she was going to space—even though there were no women or people or color participating in space exploration as she was growing up.

Dr. Jemison says that simply “looking up” brought her here. As a child, she would look up at the sky, see the stars and wonder if other children in other places in the world were looking at the same view that she had. Growing up in the 1960’s instilled into Dr. Jemison at an early age that our potential is limitless, and the political culture of civil rights, changing art and music and decolonization were all about “people declaring that they had a right to participate.” 

Photo courtesy of Elizabeth Roy

One of the biggest pieces of advice that Dr. Jemison wanted to impart on her audience was the value of confidence, and how to build confidence in situations where people are tempted to feel incapable or forget the strengths they already possess. “They told me if I wanted to lead projects I needed an M.D.,” Dr. Jemison explained. “I went to medical school because I know myself and I knew I would want to be in charge one day.” 

At 26 years old, Dr. Jemison was on call 24 hours a day, 7 days a week, 365 days a year as the Area Peace Corps Medical Officer for Sierra Leone and Liberia. She described a case where a man came back with a diagnosis of malaria from Senegal. When Dr. Jemison first took a look, the diagnosis seemed more likely to be meningitis. After making an “antibiotic cocktail,” from what she had on site, she realized this man might lose his life if they didn’t get him to a better hospital. At this point, Dr. Jemison wanted to call a military medical evacuation, and she had the authority to do it. However, another man working with her suggested calling a doctor in Ivory Coast, or a doctor at the hospital in Germany to see what he thought before making the evacuation. Dr. Jemison knew what the patient needed in this situation was to be flown to Germany regardless of the cost of the evacuation. In reflecting on this experience, she says that she could have given someone else her authority, but letting her confidence in herself and what she knew was the right thing to do would have negatively impacted her patient. 

So, how do you maintain confidence? According to Dr. Jemison, you come prepared. She knew her job was to save people’s lives, not to listen to someone else. Dr. Jemison also admonished the audience to “value, corral and protect your energy.” She couldn’t afford to always make herself available for non-emergency situations, because she needed her energy for when a patient’s life would depend on it. 

Photo courtesy of Elizabeth Roy

Dr. Jemison’s current project, 100 Year Starship, is about  trying to ensure we have the capabilities to travel to interstellar space. “The extreme nature of interstellar hurdles requires we re-evaluate what we think we know,” Dr. Jemison explained. Alpha Centauri, the next closest star, is more than 25 trillion miles away. Even if we go 10% the speed of light, it will still take us 50 years to get there. We need to be able to travel faster, the vehicle has to be self-replenishing, and we have to think about space-time changes. What Dr. Jemison calls the “long pole in the tent” is human behavior. We need to know how humans will act and interact in a small spaceship setting for possibly decades of space travel. Dr. Jemison is thinking deeply about how we can apply the knowledge we already possess to fix world problems, and how we can start preparing now for problems we may face in the future. For example, how would health infrastructure in deep space look different? How would we act on a starship that contains 5,000 people when we can’t figure out how to interact with each other on the “starship” we’re on now?

Returning to the childhood love for stargazing that brought her here, Dr. Jemison discussed towards the end of her talk that a stumbling block for the majority of people is insufficient appreciation of our connection across time and space. She has worked with a team to develop Skyfie, an app that allows you to upload photos and videos of your sky to the Sky Tapestry and explore images other people in different parts of the world are posting of their sky. Dr. Jemison’s hope is this app will help people realize that we are interconnected with the rest of the universe, and we won’t be able to figure out how to survive as a species on this planet alone. 

By Victoria Priester

Predictive maps in the brain

How do we represent space in the brain? Neuroscientists have been working to understand this question since the mid-20th century, when researchers like EC Tolman started experimenting with rats in mazes. When placed in a maze with a food reward that the rats had been trained to retrieve, the rats consistently chose the shortest path to the reward, even if they hadn’t practiced that path before.

Sam Gershman is interested in how we encode information about our environments.

Over 50 years later, researchers like Sam Gershman, PhD, of Harvard’s Gershman Lab are still working to understand how our brains encode information about space.

Gershman’s research questions center around the concept of a cognitive map, which allows the brain to represent landmarks in space and the distance between them. He spoke at a Center for Cognitive Neuroscience colloquium at Duke on Feb. 7.

Maps are formed via reinforcement learning, which involves predicting and maximizing future reward. When an individual is faced with problems that have multiple steps, they can do this by relying on previously learned predictions about the future, a method called successor representation (SR), which would suggest that the maps we hold in our brain are predictive rather than retroactive.

One specific region implicated in representations of physical space is the hippocampus, with hippocampal place cell activity corresponding to positions in physical space. In one study, Gershman found, as rats move through space, that place field activity corresponding to physical location in space skews opposite of the direction of travel; in other words, activity reflects both where the rodent currently is and where it just was. This pattern suggests encoding of information that will be useful for future travel through the same terrain: in Gershman’s words, “As you repeatedly traverse the linear track, the locations behind you now become predictive of where you are going to be in the future.”

Activation patterns in place cells correspond to both where the animal is and where the animal just was, pointing to the construction of a predictive map during learning. Graphic courtesy of Stachenfield et al., 2017.

This idea that cognitive activity during learning reflects construction of a predictive map is further supported by studies where the rodents encounter novel barriers. After being trained to retrieve a reward from a particular location, introducing a barrier along this known path leads to increased place cell activity as they get closer to the barrier; the animal is updating its predictive map to account for the novel obstacle.

This model also explains a concept called context preexposure facilitation effect, seen when animals are introduced to a new environment and subsequently exposed to a mild electrical shock. Animals who spend more time in the new environment before receiving the shock show a stronger fear response upon subsequent exposures to the box than those that receive a shock immediately in the new environment. Gershman attributes this observation to the time it takes the animal to construct its predictive map of the new environment; if the animal is shocked before it can construct its predictive map, it may be less able to generalize the fear response to the new environment.

With this understanding of cognitive maps, Gershman presents a compelling and far-reaching model to explain how we encode information about our environments to aid us in future tasks and decision making.

Brain networks change with age

Graph theory allows researchers to model the structural and functional connection between regions of the brain. Image courtesy of Shu-Hsien Chu et al.

As we age, our bodies change, and these changes extend into our brains and cognition. Although research has identified many changes to the brain with age, like decreases in gray matter volume or delayed recall from memory, researchers like Shivangi Jain, PhD, are interested in a deeper look at how the brain changes with age.

Shivangi Jain uses graph theory to study how the brain changes with age.

As a post-doctoral associate in the David Madden Lab at Duke, Jain is interested in how structural and functional connectivity in the brain change with age. Jain relies on the increasingly popular method of graph theory, which is a way of modeling the brain as a set of nodes or brain regions that are interconnected. Studying the brain in this way allows researchers to make connections between the physical layout of the brain and how these regions interact when they are active. Structural connectivity represents actual anatomical connections between regions in the brain, while functional connectivity refers to correlated activity between brain regions.

Jain’s studies use a series of tasks that test speed, executive function, and memory, each of which decline with age. Using fMRI data, Jain observed a decline in functional connectivity, where functional modules become less segregated with age.  In terms of structural connectivity, aging was associated with a decline in the strength of white matter connections and global efficiency, which represents the length between modules with shorter paths being more efficient. Thus, the aging brain shows changes at the anatomical, activational, and behavioral levels.

Jain then examined how these network-level changes played a role in the observed behavioral changes. Using statistical modeling, she found that the decline in performance in tasks for executive control could be explained by the observed changes in functional connectivity. Furthermore, Jain found that the changes in structural connectivity caused the change in functional connectivity. Taken together, these results indicate that the physical connections between areas in the brain deteriorate with age, which in turn causes a decrease in functional connectedness and a decline in cognitive ability.

Research like Jain’s can help explain the complicated relationships between brain structure and function, and how these relationships affect behavioral output.

Post by undergraduate blogger Sarah Haurin
Post by Sarah Haurin

Man’s Best Friend, Our Relationship to Dogs

The average dog costs its human owner $10,000-20,000 over the course of its lifetime, from vet care and grooming to treats and toys to the new fad of doggie DNA testing. But what’s in it for us? Researcher Kerri Rodriguez – a Duke alum of evolutionary anthropology and current grad student with Purdue University’s College of Veterinary Medicine – explores just that.

Rodriguez is a member of the OHAIRE Lab at Purdue, which stands for the Organization for Human-Animal Interaction Research and Education. Continuing her work from undergrad, Rodriguez researches the dynamic duo between humans and dogs – a relationship some 15,000 to 40,000 years in the evolutionary making. Rodriguez returned to Duke to speak on February 12th, honoring both Darwin Day and Duke’s second annual Dog Day.

It’s well-known that dogs are man’s best friend, but they do much more than just hang out with us. Dogs provide emotional support when we are stressed or anxious and are highly attentive to us and our emotional states.

In a study of 975 adult dog owners, dogs ranked closely to romantic partners and above best friends, children, parents, and siblings when their owners were asked who they turn to when feeling a variety of ways. Dogs provide non-judgmental support in a unique way. They have also been found to reduce levels of the stress hormone cortisol, lower perceived stress in individuals, improve mood, and improve energy up to 10 hours after interactions. Therapy dogs are prevalent on many college campuses now due to these impacts and are found in hospitals for the same reasons, having been found to reduce subjective pain, increase good hormones and dampen bad ones, causing some patients to require less pain medications.

(Creative Commons)

 Along with reduced stress, dogs make us healthier in other ways, from making us exercise to reducing risk of cardiovascular disease. A study of 424 heart attack survivors found that non-dog owners were four times more likely to be deceased one year after the attack than victims who owned dogs.

The increased social interaction that dogs offer their human companions is also quite amazing due to the social facilitation effect they provide by offering a neutral way to start conversations. One study with people who have intellectual disabilities found that they received 30% more smiles along with increased social interactions when out in public with a dog. Similar studies with people who use wheelchairs have produced similar results, offering that dogs decreased their loneliness in public spaces and led to more social engagements.

Rodriguez also shared results from a study dubbed Pet Wingman. Using dating platforms Tinder and Bumble, researchers found that after one month, simulated profiles containing pictures with dogs received 38% more matches, 58% more messages, and 46% more interactions than simulated profiles without. Even just having a dog in photos makes you appear more likable, happier, relaxed, and approachable – it’s science!

 A large bulk of Rodriguez’s own work is focused on dogs in working roles, particularly the roles of a service dog. She explained that unlike therapy or emotional support dogs, service dogs are trained for one person, to do work and perform tasks to help with a disability, and are the only dogs granted public access by the American Disability Association. Rodriguez is particularly interested in the work of dogs who help American veterans with post-traumatic stress disorder (PTSD).

(Creative Commons)

 Around one out of five post-9/11 military veterans have PTSD and the disorder is difficult to treat. Service dogs are becoming increasingly popular to help combat effects of PTSD, ranking at the third highest placed type of service dog in the United States. PTSD service dogs are able to use their body weight as a grounding method, provide tactile interruption, reduce hypervigilance, and prevent crowding of their veterans. However, because of the lack of research for the practice, the Veterans Association doesn’t support the use of the dogs as a therapy option. This is an issue Rodriguez is currently trying to address.           

 Working with a group called K9s for Warriors, Rodriguez’s research evaluated the mental health, social health, quality of life, and cortisol levels of veterans who have received service dogs and those who were on the wait list for dogs. Veterans with service dogs had lower PTSD symptoms, better mental health, and better social health. Rodriguez is now working on a modification to this study using both veterans and their spouses that will be able to measure these changes to their well-being and health over time, as well as assessing the dog’s health too. Unlike other organizations, K9s for Warriors uses 90% shelter dogs, most of which are mutts. Each dog is as unique as the human it is placed with, but no bond is any less special.

By Cydney Livingston

Visual Perception in Congenitally Blind Adults

Vision provides a rich source of information that most people’s lives revolve around. Yet, for blind people, how do they conceive of visual intake and what happens to regions of the brain dedicated to vision if a person doesn’t have typical visual input? These are questions that drive Marina Bedny PhD, an Assistant Professor of Psychological and Brain Sciences and principal investigator of a neuroplasticity and development lab at John Hopkins University.

Bedny spoke at Duke’s Institute for Brain Sciences on Friday, January 17th, about her work with congenitally blind adults. Her lab explores similarities and distinctions of visual perceptions between blind and seeing people and seeks to understand how nuanced, natural variation in experience shapes the human mind and brain.

Many of the studies Bedny discussed have very important linguistic components. In one trial, she investigated the meaning of verbs pertaining to light events and visual perception as compared to touch, amodal, auditory, and motion verbs.

Both blind and sighted people displayed nearly identical results when comparing the different types of verbs used in the study. This showed that there were no differences in what blind people knew about the terms. Analysis of the verbs revealed that linguistic dimensions of intensity and instability were used to evaluate the words’ comparative meanings. Blind people agreed more on the comparison of sound emission and touch perception words. This shows that blind participants have more aligned comprehension of the meanings of other sensory terms compared to sighted people.

In other cases, Bedny’s lab assessed what blind individuals know about color. One study used three object types – natural kinds, functional artifacts, and non-functional artifacts. These categories were used to evaluate agreeance not only on color, but the relevancy of color to certain objects’ functions as well.

Another crucial question of Bedny’s work looks at how the innate structure of the brain constrains cortical function. The findings show that the visual system in blind participants has been repurposed for higher cognitive functions and that portions of the visual system connected to high cognitive abilities are invaded by the visual systems. Along with repurposing visual regions for linguistic use, Bedny’s lab found that visual regions of the brain are active during numerical processing tasks too.

Blind people display additional activity in the visual centers of their brain in numerous studies beyond having the same regional brain responsiveness as sighted people. Though further research is necessary, Bedny proposes that there is a sensitive period during development that is critical to the specialization of the brain. Study participants who have adult-onset blindness do not show the same sensitivity and patterned responses in visual cortices repurposed for different functions as congenitally blind subjects.

At birth, the human cortex is pluripotent – providing the best of both worlds, Bedny said. The brain is prepared but highly flexible. Her studies have repeatedly shown that the brain is built for and transformed by language, and they underscore the importance of nature and nurture in human development.

Post by Cydney Livingston

The evolution of a tumor

The results of evolution are often awe-inspiring — from the long neck of the giraffe to the majestic colors of a peacock — but evolution does not always create structures of function and beauty.

In the case of cancer, the growth of a population of malignant cells from a single cell reflects a process of evolution too, but with much more harrowing results.

Johannes Reiter uses mathematical models to understand the evolution of cancer

Researchers like Johannes Reiter, PhD, of Stanford University’s Translational Cancer Evolution Laboratory, are examining the path of cancer from a single sell to many metastatic tumors. By using this perspective and simple mathematical models, Reiter interrogates the current practices in cancer treatment. He spoke at Duke’s mathematical biology seminar on Jan. 17.

 The evolutionary process of cancer begins with a single cell. At each division, a cell acquires a few mutations to its genetic code, most of which are inconsequential. However, if the mutations occur in certain genes called driver genes, the cell lineage can follow a different path of rapid growth. If these mutations can survive, cells continue to divide at a rate faster than normal, and the result is a tumor.

As cells divide, they acquire mutations that can drive abnormal growth and form tumors. Tumors and their metastases can consist of diverse cell populations, complicating treatment plans out patient outcomes. Image courtesy of Reiter Lab

With each additional division, the cell continues to acquire mutations. The result is that a single tumor can consist of a variety of unique cell populations; this diversity is called intratumoral heterogeneity (ITH). As tumors metastasize, or spread to other locations throughout the body, the possibility for diversity grows.

Intratumoral heterogeneity can exist within primary tumors, within metastases, or between metastases. Vogelstein et al., Science, 2013

Reiter describes three flavors of ITH. Intra-primary heterogeneity describes the diversity of cell types within the initial tumor. Intrametastatic heterogeneity describes the diversity of cell types within a single metastasis. Finally, inter-metastatic heterogeneity describes diversity between metastases from the same primary tumor.

For Reiter, inter-metastatic heterogeneity presents a particularly compelling problem. If treatment plans are made based on biopsy of the primary tumor but the metastases differ from each other and from the primary tumor, the efficacy of treatment will be greatly limited.

With this in mind, Reiter developed a mathematical model to predict whether a cell sample collected by biopsy of just the primary tumor would provide adequate information for treatment.

Using genetic sequence data from patients who had at least two untreated metastases and a primary tumor, Reiter found that metastases and primary tumors overwhelmingly share a single driver gene. Reiter said this confirmed that a biopsy of the primary tumor should be sufficient to plan targeted therapies, because the risk of missing driver genes that are functional in the metastases proved to be negligible.

 In his next endeavors as a new member of the Canary Center for Cancer Early Detection, Reiter plans to use his knack for mathematical modeling to tackle problems of identifying cancer while still in its most treatable stage.  

Post by undergraduate blogger Sarah Haurin

Post by Sarah Haurin

Understanding and Addressing Vaccine Hesitancy

In the midst of increasing outbreaks of vaccine-preventable disease, Duke global health researcher Lavanya Vasudevan (PhD, MPH, LPH) is investigating the reasons for vaccine hesitancy with focus on America and Tanzania.

Vaccine hesitancy refers to the refusal of or delay in accepting vaccinations, despite their availability. Vasudevan hopes to figure out what interventions will change the minds of target populations on such a heated topic.

She presented at Duke’s Global Health Institute on November 15th about her “big 5 research areas:” identification of sub-optimal vaccine uptake, contextualization of barriers to uptake, measuring parental concern, debunking misinformation, and developing and testing strategies aimed at addressing vaccine hesitancy.

Lavanya Vasudevan presenting at Duke’s Global Health Institute.

Globally, Vasudevan says that there are too many kids playing catch-up with their vaccines, meaning that even when children are getting vaccinated, the vaccinations they receive are not on time with the scheduled progression of immunizations, putting them at risk for contracting disease. Different countries measure vaccination coverage in different ways and on different timelines, which makes it harder to understand where sub-optimal vaccine uptake is happening. A better standard for assessing timeliness of vaccines is crucial. Vasudevan is working to confront this issue to gain better understanding of who and where hesitancy is coming from.

Identification of specific regions of vaccine hesitancy is crucial to navigating interventions, she added. Vasudevan wants to be able to pinpoint areas and understand the context-specific issues that vary across time, place, and vaccine type in order to be most effective.

She said that her work in Tanzania has provided insight to the problem of geographic accessibility and lack of proper supplies in the country, prompting delayed and missed vaccinations among 72% of children, according to self-reporting by their mothers. Tanzanian mothers expressed their frustrations during interviews. They frequently arrange to go to a clinic where vaccinations are offered on specific dates and travel long distances to get there. However, if there are not enough kids who come to be vaccinated, the facilities just won’t vaccinate those who did manage to show up for immunizations.  

Though the qualitative data gained through extensive interviewing and group discussions has been extremely useful and rich, Vasudevan says there is a need for quantitative tools that can rapidly screen for parent’s concerns when it comes to the vaccination of their children. Qualitative data is simply not informative on a large scale.

A review of pre-existing measures evaluated 159 studies, but the quantitative scales found were often complex and context-specific, as well as designed and validated for high-income settings. On this basis, Vasudevan and her larger research team decided to design a scale for use in Tanzania because of its specificity in addressing the contexts of the region. Tailored counseling is also being used to address the local concerns and issues.

Another parallel research project that Vasudevan is involved with aims to identify common vaccine myths, creating a taxonomy to tag these myths and developing and testing an intervention that will highlight and debunk misinformation found on the internet. The current end-goal for the work being done is a “vaccine fact-checker” that could be used on web browsers to identify the myths in vaccine-related information found online.

A common example of needles and vials containing immunization products (Creative Commons).

In closing, Vasudevan identified three main areas for developing and testing intervention strategies. She says these are behavioral nudges, educational strategies, and vaccination policy and legislation.

There is a need for parent-focused strategies that recognize parental concern for their child’s safety on all sides of the vaccination issue, she said. Stringent policies are likely to alienate hesitant parents rather than increasing vaccine uptake. This is why Vasudevan is so focused on understanding and contextualizing issues specific to hesitancy among parents. It seems that increase of vaccinations and improvement of immunization timeliness lies in hearing and reconciling with parental apprehensions and underlying root causes of these hesitations.

One area of focus that Vasudevan feels is underutilized is pre-natal care. Reduction of the divide between obstetrician/gynecologists (OBGYNs) and pediatric care may be a crucial component to educate parents and enrich their understanding about vaccinations following the birth of the child.

Beyond everything else, she said, building trust is essential; simply providing information to parents is not enough. It takes time and empathy to be enable parents to make healthy vaccination choices. Providing credible resources in a safe environment while tuning in to the causes of hesitancy may be the next step to the reduction of vaccine-preventable disease, a current top ten threat to global health.

Post by Cydney Livingston

The Anthropology of “Porkopolis”

Alex Blanchette, cultural anthropologist and lecturer in anthropology and environmental studies at Tufts University, is a scholar of pork production.

As America’s pork industry is continually pushed to ever greater production, so are the human beings who labor to breed, care for, and slaughter these animals.

Blanchette, who gave a talk hosted by the Ethnography Workshop at Duke on November 4th, said there is an intimate relationship between pig and person. The quality of the factory farm worker’s life is tied to that of the porcine species.

Alex Blanchette of Tufts University

Blanchette’s current work will be published in the 2020 ethnographic book – Porkopolis: American Animality, Standardized Life, and the “Factory” Farm. The book is focused on the consequences of human labor and identity that are bound to the pig – an animal which has become more industrialized over time due to corporations’ goal of a mass produced, standardized pig predictable in nature, uniform in existence, and easy to slaughter.

A common practice in factory farming is the ‘runting’ of litters, genetically making piglets smaller to increase the number each sow produces. But this practice has propelled a fundamental shift in the need for human workers to act as neonatal nurses, what Blanchette calls “external prosthetics,” to care for the newborns. Blanchette described one extraordinary worker responsible for taking care of piglet litters, saving the weak and deformed after birth. She has taken measures so drastic as to give a piglet mouth-to-mouth, incubate them in her pockets, and quickly form body-casts out of duct-tape for the small creatures. This worker has had the chance to study over 400,000 piglets in her seven-year career, encountering conditions of the pig body that no scientist has seen in real life.

Blanchette explained the active engagement required in any portion of the factory production. For example, people working with pregnant sows have to be extremely conscious of the way that the pigs are perceiving them to keep the sensory state of the mother pigs balanced. This means avoiding touching them unless work requires it, not wearing perfumes on the job, and taking overall care and precision in every motion throughout the workday. The danger is the risk of causing mass miscarriages and spontaneous abortions within a barn of sows because of their genetically engineered weakness and inability to handle stresses.

Piglets nursing in a device known as a farrowing crate.

Blanchette said one worker could be seen standing in the exact same place over the course of 1,000 compiled picture frames. He developed this habit to prevent large hogs in open pens from knocking him down and biting his legs while he was working. This is something that Blanchette said he couldn’t manage for more than a few minutes even though he too has worked within the pork industry before.

Workers on slaughter and “disassembly” lines are responsible for making the same exact cut or slice 9,500 times a day.

And finally, the conformation of human labor to the precisions of the factory pig often does not stop at the end of the work shift. In rural factory farming areas, corporations try to re-engineer the human communities in which their workers live to further regulate the human body outside of work because of potential impacts on the pigs. For example, workers’ socialization has been monitored by companies in some cases due to the threat of communicable disease reaching the hogs through human kinship.

No worker knows the pig from birth to death, but for the individual portion of the pig’s life for which they are responsible, they are bound intimately and intricately to the hog, Blanchette said. These people are also disproportionately people of color and immigrant workers who are underpaid for how strenuous, demanding, and encapsulating this labor is. Workers in factory farms often have little protections, and Blanchette’s work gives new life to the consequences of industrial capitalism in America as the pig has become a product of vertical integration in rural communities.

We have long been moving at the speed limits of human physiology in the pork industry,  Blanchette said. In 2011, one company’s annual effort to improve their corporation was to build a new human clinic on the jobsite to treat cuts and injuries acquired on the slaughter lines. This clinic was also responsible for assessing new hires in order to match the strongest part of their body to a place on the line where they would be most productive.

The interior of a typical confined animal feeding operation (CAFO).

Factory farms are actively searching for new money to be found in the pig and to have a closed-loop system which uses every aspect of its life and death for profit. This has caused a deep integration of the “capital swine” into everyday human life for the laborers and communities sustained by these economic ventures.

The Trump administration recently removed standards for pork slaughter line speeds and ultimately reduced overall regulations. People like Blanchette are already considering something you too might be wondering, What happens next? Where does pork and the human labor behind it go from here?

Post by Cydney Livingston

Does aging make our brains less efficient?

We are an aging population. Demographic projections predict the largest population growth will be in the oldest age group – one study predicted a doubling of people age 65 and over between 2012 and 2050. Understanding aging and prolonging healthy years is thus becoming increasingly important.

Michele Diaz and her team explore the effects of aging on cognition.

For Michele Diaz, PhD, of Pennsylvania State University, understanding aging is most important in the context of cognition. She’s a former Duke faculty member who visited campus recently to update us on her work.

Diaz said the relationship between aging and how we think is much more nuanced than the usual stereotype of a steady cognitive decline with age.

Research has found that change in cognition with age cannot be explained as a simple decline: while older people tend to decline with fluid intelligence, or information processing, they maintain crystallized intelligence, or knowledge.

Diaz’s work explores the relationship between aging and language. Aging in the context of language shows an interesting phenomenon: older people have more diverse vocabularies, but may take longer to produce these words. In other words, as people age, they continue to learn more words but have a more difficult time retrieving them, leading to a more frequent tip-of-the-tongue experience.

In order to understand the brain activation patterns associated with such changes, Diaz conducted a study where participants of varying ages were asked to name objects depicted in images while undergoing fMRI scanning. As expected, both groups showed less accuracy in naming of less common objects, and the older adult group showed a slightly lower naming accuracy than the younger.

Additionally, Diaz found that the approach older adults take to solving more difficult tasks may be different from younger adults: in younger adults, less common objects elicited an increase in activation, while older adults showed less activation for these more difficult tasks.

Additionally, an increase in activation was associated with a decrease in accuracy. Taken together, these results show that younger and older adults rely on different regions of the brain when presented with difficult tasks, and that the approach younger adults take is more efficient.

In another study, Diaz and her team explored picture recognition of objects of varying semantic and phonological neighborhood density. Rather than manipulation of how common the objects presented in the images are, this approach looks at networks of words based on whether they sound similar or have similar meanings. Words that have denser networks, or more similar sounding or meaning words, should be easier to recognize.

An example of a dense (left) and sparse (right) phonological neighborhood. Words with a greater number of similar sounding or meaning words should be more easily recognized. Image courtesy of Vitevitch, Ercal, and Adagarla, Frontiers in Psychology, 2011.

With this framework, Diaz found no age effect on recognition ability for differences in semantic or phonological neighborhood density. These results suggest that adults may experience stability in their ability to process phonological and semantic characteristics as they age.

Teasing out these patterns of decline and stability in cognitive function is just one part of understanding aging. Research like Diaz’s will only prove to be more important to improve care of such a growing demographic group as our population ages.

Post by undergraduate blogger Sarah Haurin

Post by undergraduate blogger Sarah Haurin

Legendary Paleontologist Richard Leakey Visits Duke

Hoping to catch up with an old friend who is a professor at Duke, Richard Leakey accepted an invitation to speak at the university on Oct. 22, though he “gave up public speaking to a large extent many years ago.”

Richard E. Leakey visited Duke on Oct. 22, 2019.

Leakey, age 74, is a world-renowned pioneer in Paleoanthropology – the study of the human fossil record – and is also well-known for his involvement in Kenyan politics and lifelong efforts towards conservation and wildlife protection. Once, he famously burned twelve tons of elephant tusks that were confiscated from poachers, which gathered international attention and helped usher in a global ban on the ivory trade.

Leakey came to paleontology by heredity. He is one of an entire family of Paleo-pioneers. His mother, Mary, discovered a skull in Africa that was dated to 1.75 million years ago (MYA) in 1960. Leakey said that this “electrified interest in the origin story” – that is, the human origin story. When his father, Louis, showed that the “quite clever” ancient tools he had discovered were made around 1.75 MYA, the original idea that human origins began outside of Africa began to change.

Leakey said the British people were hoping that “if we had evolved … let it happen in England” and if not England, then Asia, but this was not to be the case. At first, Louis Leakey was ostracized because of his work and discoveries of human origins in Africa. This helped steer Richard away from academics because of the fights that he saw his father endure.

Leakey’s famous 1984 Kenyan discovery, “Turkana Boy,” a 1.5 million-year-old, nearly-complete specimen of Homo erectus. (Wikipedia)

Successfully achieving his self-described ambition to not finish high school, Richard Leakey was thrown out of school at age 16. Yet today he is accredited with many awards, has written at least eight books, and has advanced the Leakey family legacy of discovery. From 1968 to the present day, he and fellow workers have discovered enormous numbers of fossils of our ancestors along the East and West shores of Lake Turkana in Kenya, which have an age span from 4.5 MYA to our very recent ancestors, which Leakey calls “fossil us.”

Leakey described for the Duke audience in an overflowing auditorium at the Nasher Museum a scenario he facilitated with colleagues and students.

He had taken a group to a camp site to talk about evolution and asked them to perform some tasks. First, they were charged to make tools from stone. The following day, they were led to a freshly slaughtered goat. Leakey told his pupils to butcher the goat and remove the flesh from its carcass.

After several hours watching the individuals try to pull at the goat with their hands to no avail, Leakey suggested that they might use their new stone tools. So they did, but they still could not get through the animal’s tough hide, even with a blade.

He said that during human evolution, our imagination was turned on genetically and this gave early humans the “capability to think of things that weren’t.” There is lots of work to be done studying an ancient period over 3.5 million years that Leakey says lends itself to “early ancestry of speech, imagination, [and] cooperation.” He is hopeful for the knowledge and new understandings that will come from investigation of this period. 

“Why not ask someone to help you?” Leakey prompted again, and within an hour, nothing was left of the goat. The exercise demonstrated that though other monkeys and apes use stone, it is the human’s vocal communication and sense of working together that sets us apart, says Leakey.     

Leakey’s current project is a “mega-museum” to “cerebrate and celebrate the story of the African origin.” The origin story which his parents first provided crucial evidence for is hugely important to the African continent and to the people of Africa and because we have “desecrated our motherland,” he said. Leakey wants the museum to highlight stages of evolution, genetics, climate, ecology, other species, and extinctions.

An architectural rendering of Ngaren: The Museum of Humankind to be built near Nairobi. (Studio Libeskind )

Before moving into the panel and Q&A portion of his talk, which was moderated by Duke professors Steven Churchill and Anne Yoder, Leakey prompted the audience to think about climate change, asking why we do not think we need to save ourselves. If we die, then other species go with us.

“Don’t for a minute think that climate change isn’t a real crisis that we’re in together,” Leakey said, earning a round of applause.

Post by Cydney Livingston

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