Duke Research Blog

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

Category: Neuroscience (Page 1 of 9)

How A Bat’s Brain Navigates

Most of what we know about how the hippocampus, a region of the brain associated with memory formation and spatial representations, comes from research done on rodents. Rat brains have taught us a lot, but researchers in Israel have found an interesting alternative model to understanding how the hippocampus helps mammals navigate: Bats.

The Egyptian fruit bat proved the perfect subject for studies of mammalian navigation.

Weizmann Institute neurophysiologist Nachum Ulanovsky, PhD, and his team have looked to bats to understand the nuances of navigation through space. While previous research has identified specific cells in the hippocampus, called place cells, that are active when an animal is located in a specific place, there is not much literature describing how animals actually navigate from point A to point B.

Nachum Ulanovsky

Ulanovsky believes that bats are an ingenious model to study mammalian navigation. While bats have the same types of hippocampal neurons found in rats, the patterns of bats’ neurons’ firings more closely match that of humans than rats do.

Ulanovsky sought to test how bats know where they are going. Using GPS tracking equipment, his team found that wild bats that lived in a cave would travel up to 20 kilometers to forage fruit from specific trees. Night after night, these bats followed similar routes past perfectly viable food sources to the same tree over and over again.

The understanding of hippocampal place cells firing at specific locations doesn’t explain the apparent guided travel of the bat night after night, and other explanations like olfactory input do not explain why the bats fly over good food sources to their preferred tree.

The researchers designed an experiment to test how bats encode the 3D information necessary for this navigation. By letting the bats fly around and recording brain activity, Ulanovsky and team found that their 3D models are actually spherical in shape. They also found another type of hippocampal cells that encode the orientation the bat is facing. These head direction cells operate in a coordinate system that allows for a continuity of awareness of its orientation as the animal moves through space.

http://www.cell.com/cms/attachment/2091916945/2076305003/gr1_lrg.jpg

Ulanovsky found bats relied on memory to navigate toward the goal.

To understand how the bats navigate toward a specific goal, the researchers devised another experiment. They constructed a goal with a landing place and a food incentive. The bat would learn where the goal was and find it. In order to test whether the bats’ ability to find the goal was memory-based, or utilized the hippocampus, the researchers then conducted trials where the goal was hidden from the bats’ view.

To test whether the bats’ relied on memory, the Ulvanosky team measured the goal direction angle, or the angle between the bat’s head orientation and the goal. After being familiarized with the location of the goal, the bats tended toward a goal-direction angle of zero, meaning they oriented themselves toward the goal even when the goal was out of sight.

Continued research identified cells that encode information about the distance the bat is from the goal, the final piece allowing bats to navigate to a goal successfully. These hippocampal cells selectively fire when the bat is within specific distances of the goal, allowing for an awareness of location over distance.

While Ulanovsky and his team have met incredible success in identifying new types of cells as well as new functions of known cells in the hippocampus, further research in a more natural setting is required.

“If we study only under these very controlled and sterile environments, we may miss the very thing we are trying to understand, which is behavior,” Ulanovsky concluded.

By Sarah Haurin

Dopamine, Drugs, and Depression

The neurotransmitter dopamine plays a major role in mental illnesses like substance abuse disorders and depressive disorders, as well as a more general role in reward and motivational systems of the brain. But there are still certain aspects of dopamine activity in the brain that we don’t know much about.

Nii Antie Addy and his lab are interested in the role of dopamine in substance abuse and mood disorders.

Duke graduate Nii Antie Addy, PhD, and his lab at Yale School of Medicine have been focusing on dopamine activity in a specific part of the brain that has not been studied: the ventral tegmental area (VTA).

To understand the mechanisms underlying this association, Addy and his team looked at cue-induced drug-seeking behavior. Using classical conditioning, rats can be trained to pair certain cues with the reward of drug administration. When a rat receives an unexpected award, dopamine activity increases. After conditioning, dopamine is released in response to the cue more  than to the drug itself. Looking at the patterns of dopamine release in rats who are forced to undergo detoxification can thus provide insight into how these cues and neurotransmitter activity relate to relapse of substance abuse.

When rats are taught to self-administer cocaine, and each administration of the drug is paired with the cue, after a period of forced detoxification, the rodents continue to try to self-administer the drug, even when the drug is withheld and only the cue is presented. This finding again demonstrates the connection between the cue and drug-seeking behavior.

Studying the activity in the VTA gave additional insights into the regulation of this system. During the period of abstinence, when the rodents are forced to detox, researchers observed an increase in the activity of cholingergic neurons, or neurons in the brain system that respond to the neurotransmitter acetylcholine.

Using these observations, Addy and his team sought to identify which of the various receptors that respond to acetylcholine can be used to regulate the dopamine system behind drug-seeking behaviors. They discovered that a specific type of acetylcholine receptor, the muscarinic receptor, is involved in more general reward-seeking behaviors and thus may be a target for therapies.

Using Isradipine, a drug already approved by the FDA for treatment of high blood pressure, Addy designed an experiment to test the role of these muscarinic receptors. He co-opted the drug to act as a calcium antagonist in the VTA and thus increase dopamine activity in rodents during their forced detox and before returning them to access to cocaine. The outcome was promising: administration of Isradipine was associated with a decrease in the coke-seeking behavior of rodents then placed in the chamber with the cue.

The understanding of the role of cholinergic neurons in regulation of dopamine-related mental illnesses like substance-abuse also contributes insights into depressive and anxiety disorders. If the same pathway implicated in cue-induced drug-seeking were involved in depressive and anxious behaviors, then increasing cholinergic activity should increase pro-depressive behavior.

Addy’s experiment yielded exactly these results, opening up new areas to be further researched to improve the treatment of mood disorders.

Post by Sarah Haurin

 

Morphogenesis: All Guts and Morning Glories

What is morphogenesis? Morphogenesis examines the development of the living organisms’ forms.

It also is an area of research for Lakshminarayanan Mahadevan, Professor of Applied Mathematics, Organismic and Evolutionary Biology and Physics at Harvard University. On his presentation in the Public Lectures Unveiling Math (PLUM) series here at Duke, he credited the beginnings of morphogenesis to D’Arcy Wentworth Thompson, author of the book On Growth and Form.

Mathematically, morphogenesis focuses on how different rates of growth change the shapes of organisms as they develop. Cell number, cell size, cell shape, and cell position comprise the primary cellular factors of multicellular morphogenesis, which studies larger structures than individual cells and is Mahadevan’s focus.

Effects on tissues appear through changes in sizes, connectivities, and shapes, altering the phenotype, or the outward physical appearance. All these variables change in space and time. Professor Mahadevan presented on morphogenesis studies that have been conducted on plant shoots, guts, and brains.

Research on plant shoots often concentrates on the question, “Why do plant shoots grow in such a wide variety of directions and what determines their shapes?” The picture below shows the different postures appearances of plant shoots from completely straight to leaning to hanging.

Can morphogenesis make sense of these differences? Through mathematical modeling, two stimuli for shoots’ shapes was determined: gravity and itself. Additionally, elasticity as a function of the shoots’ weight plays a role in the mathematical models of plant shoots’ shapes which appear in Mahadevan’s paper co-written with a fellow professor, Raghunath Chelakkot. Mahadevan also explored the formation of flower and leaf shapes with these morphogenesis studies. 

Over twenty feet of guts are coiled up inside you. In order to fit these intestines inside the mammals, they must coil and loop. But what variables determine how these guts loop around? To discover the answer to this question, Mahadevan and other researchers examined chick embryos which increase their gut lengths by a factor greater than twenty over a twelve-day span. They were able to create a physical model using a rubber tube sewn to a sheet that followed the same patterns as the chicks’ guts. Through their observation of not only chicks but also quail and mice, Mahadevan determined that the morphogenesis of the guts has no dependence on genetics or any other microscopic factors.

Mahadevan’s study of how the brain folds occurs through MRI images of human fetal development. Initially, barely any folding exists on fetal brains but eventually the geometry of the surrounding along with local stress forms folds on the brain. By creating a template with gel and treating it to mimic the relationship between the brain’s gray matter and white matter, Mahadevan along with other researchers discovered that they could reproduce the brain’s folds. Because they were able to recreate the folds through only global geometry and local stress, they concluded that morphogenesis evolution does not depend on microscopic factors such as genetics. Further, by examining if folding regions correlate with the activity regions of the brain, questions about the effect of physical form on abilities and the inner functions of the brain.

  

     

On a Mission to Increase Exercise

Dr. Zachary Zenko of the Center for Advanced Hindsight at Duke is on a mission to get people to exercise. He shared this mission and his research aimed at achieving this mission at Duke’s Exercise and the Brain Symposium on December 1st.

Dr. Zenko started out with a revealing statistic: Only 1 in 10 people meet the United States activity guidelines for exercise. While I wasn’t completely shocked at this fact as the U.S. is known for its high rates of obesity and easy access to fast-food, I was definitely eager to learn more about how Dr. Zenko planned to fight this daunting statistic.

Next, Dr. Zenko pointed out a common assumption in exercise psychology: if people know how good exercise is for them, they will exercise. However, this hasn’t proven to be true. Most people already know that they should be exercising, but don’t. And those that do often quickly drop out.

Then Dr. Zenko began to break down Dual-Process Theory in Behavioral Economics. Type 1 Processes are those that are fast and non-conscious, while Type 2 Processes are those that are controlled and conscious. While research on exercise usually focuses on Type 2 processes, Zenko believes that we must focus on both.

Ideally, exercise would involve the affect heuristic, which is a mental shortcut in which an emotional response drives an individual. This heuristic involves Type 1 processes. Dr. Zenko’s goal was to shift away from only considering Type 2 processes, and instead focus on using Type 1 processes to make exercise more appealing.

How did he propose doing this? By continually decreasing the difficulty of exercise. By changing the slope of the intensity of a workout and having a continually declining heart rate, exercisers could have a more pleasant experience. In addition, this positive experience could influence memory and make an individual more likely to exercise in the future.

Dr. Zenko put this hypothesis to the test by having unfit adults exercise while continually decreasing the intensity throughout the workout. While test subjects exercised, he measured the amount of pleasure experienced by asking “How do you feel right now?” at certain intervals. This new exercise method  has the most potential when starting at the highest intensity levels because it leaves more room to change the slope of the workout intensity throughout, leading to an overall more pleasurable workout.

Looking forward, this new method of exercise could possibly change the way we think about exercise. It may not only involve doing the right amount of exercise, but also doing the right kind of exercise that leaves us more likely to exercise in the future. Considering that traditional methods of promoting exercise, such as educating people about its benefits, have not been particularly successful thus far, Dr. Zenko’s method is very exciting.

Dr. Zenko wrapped up his talk by suggesting that people consider exercise prescriptions that are safe, effective, pleasant and enjoyable. As exercise has become a huge part of my weekly routine throughout college, I will definitely take this advice to heart. Maybe even look out for me lowering my intensity during a workout soon in a gym near you?

By Nina Cervantes

Exercise is Good for Your Head and Might Fight Alzheimer’s

Recent studies have confirmed that exercising is just about the best thing you can do for your brain health.

Dan Blazer, MD is a psychiatrist who studies aging.

On Dec. 1 during the DIBS event, Exercise and the Brain, Duke psychiatrist Dan Blazer reported findings about the relationship between physical activity and brain health. After lots of research, study groups at the National Academy of Medicine  concluded that their number one recommendation to those experiencing “cognitive aging” is exercise.

Processing speed, memory, and reasoning decline over time in every one of us. But thankfully, simple things like riding a bike or playing pick up basketball can help keep our minds fresh and at their best possible level.

One cool thing a committee conducting the research did to advertise their findings was create keychains saying “take your brain for a walk.” There’s a little image of a brain with legs walking. They wanted to get the word out that physical activity has another benefit than just staying in shape — it can also support your cognitive health.

However, the committees are having a hard time motivating people to exercise in the first place. Even after hearing their findings, it’s not like people everywhere are suddenly going to get off their couches and hit the gym. A world with healthier people — both physically and mentally — sounds nice, but getting there is much more than a matter of publishing these studies.

And, as always, too much of a good thing can make it harmful. While there does seem to appear a potential “biological gradient,” where greater physical activity correlated with better outcomes, you can’t just run a marathon every day of the week and then ~boom~ aging hardly affects your brain anymore. You don’t want to do that to yourself. Just get a healthy amount of exercise and you’ll be keeping your brain young and smart.

One of the best parts about why exercising is so great for you and your brain is because it helps you sleep (and we all know how important sleep is). If you ever have trouble going to bed or are having disrupted sleeps, physical activity could be your savior. It’s a much healthier option for your brain than taking stuff like melatonin, and you’ll get fit in the process.

Regarding exercising and Alzheimer’s, a disease where vital mental functions deteriorate, studies have unfortunately been insufficient to conclude anything. But if getting Alzheimer’s is your worst fear, I’m sure staying active can’t hurt as a preventative. More research on this topic is being conducted as we speak.

When is the best time to start exercising, in order to reap the maximum cognitive benefits, you ask? Well, the sooner the better. As Blazer said, “exercising helps in maintaining or improving cognitive function in later life,” so you better get on that. Go outside and get moving!

Will Sheehan      Post by Will Sheehan

 

 

How We Know Where We Are

The brain is a personalized GPS. It can keep track of where you are in time and space without your knowledge.

The hippocampus is a key structure in formation of memories and includes cells that represent a person’s environment.

Daniel Dombeck PhD, and his team of researchers at Northwestern University have been using a technique designed by Dombeck himself to figure out how exactly the brain knows where and when we are. He shared his methods and findings to a group of researchers in neurobiology at Duke on Tuesday.

Domeck and his lab at Northwestern are working at identifying exactly how the brain represents spatial environments.

The apparatus used for these experiments was adapted from a virtual reality system. They position a mouse on a ball-like treadmill that it manipulates to navigate through a virtual reality field or maze projected for the mouse to see. Using water as a reward, Dombeck’s team was able to train mice to traverse their virtual fields in a little over a week.

In order to record data about brain activity in their mice as they navigated virtual hallways, Dombeck and his team designed a specialized microscope that could record activity of single cells in the hippocampus, a deep brain structure previously found to be involved in spatial navigation.

The device allows researchers to observe single cells as a mouse navigates through a simulated hallway.

Previous research has identified hippocampal place cells, specialized cells in the hippocampus that encode information about an individual’s current environment. The representations of the environment that these place cells encode are called place fields.

Dombeck and his colleague Mark Sheffield of the University of Chicago were interested in how we encode new environments in the hippocampus.

Sheffield studied the specific neural mechanisms behind place field formation.

After training the mice to navigate in one virtual environment, Sheffield switched the virtual hallway, thus simulating a new environment for the mouse to navigate.

They found that the formation of these new place cells uses existing neural networks initially, and then requires learning to adapt and strengthen these representations.

After identifying the complex system representing this spatial information, Dombeck and colleagues wondered how the system of representing time compared.

Jim Heys, a colleague of Dombeck, designed a new virtual reality task for the lab mice.

In order to train the mice to rely on an internal representation of passing time, Heys engineered a door-stop task, where a mouse traversing the virtual hallway would encounter an invisible door. If the mouse waited 6 seconds at the door before trying to continue on the track, it would be rewarded with water. After about three months of training the mice, Heys was finally able to collect information about how they encoded the passing of time.

Heys indentified cells in the hippocampus that would become active only after a certain amount of time had passed – one cell would be active after 1 second, then another would become active after 2 seconds, etc. until the 6-second wait time was reached. Then, the mouse knew it was safe to continue down the hallway.

When comparing the cells active in each different task, Dombeck and Heys found that the cells that encode time information are different from the cells that encode spatial information. In other words, the cells that hold information about where we are in time are separate from the ones that tell us where we are in space.

Still these cells work together to create the built-in GPS we share with animals like mice.

By Sarah Haurin

New Blogger Nirja Trivedi: Neuroscience Junior with Infinite Curiosity

My name is Nirja Trivedi and I’m a junior from Seattle interested in the intersections between health, technology and business. At Duke, I’m the co-president of P.A.S.H., a writer for the Standard and a member of B.O.W.

Nirja Trivedi blocking the sun with her hand

Nirja Trivedi

During high school, I considered liberal arts and scientific research to be separate disciplines: if technology was my strength then philosophy must be my weakness. In my two years at Duke, I have experienced the duality of these fields through participating in the Global Health Focus Program, developing my own research projects, working with professors and now applying to write for Duke Research. Science truly is for everyone; no matter your field, interests or opinion. Research and discovery are conduits for every mind. Research isn’t just the forefront of innovation, it paves the way for the future.

Growing up with a passion for service and influenced by my family in the medical field, the research I leaned towards combined aspects of community and health. My senior project in high school examined traumatic brain injury (TBI) in youth sports, which provided the research-based approach for designing my own Concussion Prevention Program. After my first semester, I wanted to discover what kinds of research I wanted to fully integrate myself in. I began research with the Duke Institute of Brain Sciences and spent my summer volunteering for the Richman Lab, which examines the effects of psychosocial factors like discrimination, social hierarchies and power. After I declared my Neuroscience major, I spent the year assisting in studies at the Autism Clinic, sparking my interest in technology.

Nirja Trivedi on a mountain top

Nirja Trivedi on a mountain top.

Now going into my third year, my interests in scientific discovery have only grown. From insight into the human psyche and social economic behavior to medical advances, I love the complexity of the human mind and how it fuels innovation.

My unrestricted interests guided me to the Innovation & Entrepreneurship Certificate as well as this writing position, both which foster an environment of curiosity and inspiration. Through writing, I hope to connect with faculty, discover areas of research I never knew existed, widen my breadth of scientific knowledge, and connect students to research opportunities. The threshold of knowledge is where you draw the line – why not make it infinite?

Post by Nirja Trivedi

New Blogger Sarah Haurin, Neuroscience Sophomore With a Thing for Criminal Minds

Hello! My name is Sarah Haurin (rhymes with Heron), and I am a sophomore at Duke. Along with being pre-med, I am pursuing a double major in neuroscience and German. I grew up outside of Philadelphia, Pennsylvania, and I originally fell in love with Duke both because of its vast research opportunities and also its mild winters. In grade school, a requirement to read nonfiction books led me to start reading popular science books for fun. Beginning with books about forensic science and articles about the chemistry of cooking, I soon expanded my interest to include natural and health sciences.

Since then, I have discovered my favorite genres to be abnormal psychology and biomedical research (my favorites being You Are Not So Smart and The Psychopath Whisperer), which interestingly enough make great beach reads (as evidenced by this picture of me from my family’s most recent vacation to Hilton Head Island, SC). In high school, I decided to take this love of reading scientific literature to a new place, and I joined the school newspaper, which allowed me to share recent and exciting findings with my peers through my articles in our health and science pages.

Sarah reading non-fiction at the beach.

I have always loved writing, which is what originally led me to joining my high school newspaper, and through my roles as section editor and eventually editor-in-chief, I came to appreciate the whole writing and publishing process. At Duke, I have written several articles for The Chronicle about the impressive and diverse ongoing research going on here at Duke.

I hope that being a well-rounded person, by allowing myself to enjoy activities not directly related to my majors, will eventually help me to be a better doctor, but for now I just enjoy the ability to combine my loves of writing and science. I hope to be able to further pursue this combination by writing for the Duke Research Blog.

One of the aspects of Duke’s community that I love the most is its diversity, which extends from the people who make up the student and faculty to the passions and interests that they pursue. I hope that writing for the Duke Research Blog will provide me with the opportunity to meet more of the incredibly passionate people who make up Duke’s campus.

Post by Sarah Haurin

Students Share Research Journeys at Bass Connections Showcase

From the highlands of north central Peru to high schools in North Carolina, student researchers in Duke’s Bass Connections program are gathering data in all sorts of unique places.

As the school year winds down, they packed into Duke’s Scharf Hall last week to hear one another’s stories.

Students and faculty gathered in Scharf Hall to learn about each other’s research at this year’s Bass Connections showcase. Photo by Jared Lazarus/Duke Photography.

The Bass Connections program brings together interdisciplinary teams of undergraduates, graduate students and professors to tackle big questions in research. This year’s showcase, which featured poster presentations and five “lightning talks,” was the first to include teams spanning all five of the program’s diverse themes: Brain and Society; Information, Society and Culture; Global Health; Education and Human Development; and Energy.

“The students wanted an opportunity to learn from one another about what they had been working on across all the different themes over the course of the year,” said Lori Bennear, associate professor of environmental economics and policy at the Nicholas School, during the opening remarks.

Students seized the chance, eagerly perusing peers’ posters and gathering for standing-room-only viewings of other team’s talks.

The different investigations took students from rural areas of Peru, where teams interviewed local residents to better understand the transmission of deadly diseases like malaria and leishmaniasis, to the North Carolina Museum of Art, where mathematicians and engineers worked side-by-side with artists to restore paintings.

Machine learning algorithms created by the Energy Data Analytics Lab can pick out buildings from a satellite image and estimate their energy consumption. Image courtesy Hoël Wiesner.

Students in the Energy Data Analytics Lab didn’t have to look much farther than their smart phones for the data they needed to better understand energy use.

“Here you can see a satellite image, very similar to one you can find on Google maps,” said Eric Peshkin, a junior mathematics major, as he showed an aerial photo of an urban area featuring buildings and a highway. “The question is how can this be useful to us as researchers?”

With the help of new machine-learning algorithms, images like these could soon give researchers oodles of valuable information about energy consumption, Peshkin said.

“For example, what if we could pick out buildings and estimate their energy usage on a per-building level?” said Hoël Wiesner, a second year master’s student at the Nicholas School. “There is not really a good data set for this out there because utilities that do have this information tend to keep it private for commercial reasons.”

The lab has had success developing algorithms that can estimate the size and location of solar panels from aerial photos. Peshkin and Wiesner described how they are now creating new algorithms that can first identify the size and locations of buildings in satellite imagery, and then estimate their energy usage. These tools could provide a quick and easy way to evaluate the total energy needs in any neighborhood, town or city in the U.S. or around the world.

“It’s not just that we can take one city, say Norfolk, Virginia, and estimate the buildings there. If you give us Reno, Tuscaloosa, Las Vegas, Pheonix — my hometown — you can absolutely get the per-building energy estimations,” Peshkin said. “And what that means is that policy makers will be more informed, NGOs will have the ability to best service their community, and more efficient, more accurate energy policy can be implemented.”

Some students’ research took them to the sidelines of local sports fields. Joost Op’t Eynde, a master’s student in biomedical engineering, described how he and his colleagues on a Brain and Society team are working with high school and youth football leagues to sort out what exactly happens to the brain during a high-impact sports game.

While a particularly nasty hit to the head might cause clear symptoms that can be diagnosed as a concussion, the accumulation of lesser impacts over the course of a game or season may also affect the brain. Eynde and his team are developing a set of tools to monitor both these impacts and their effects.

A standing-room only crowd listened to a team present on their work “Tackling Concussions.” Photo by Jared Lazarus/Duke Photography.

“We talk about inputs and outputs — what happens, and what are the results,” Eynde said. “For the inputs, we want to actually see when somebody gets hit, how they get hit, what kinds of things they experience, and what is going on in the head. And the output is we want to look at a way to assess objectively.”

The tools include surveys to estimate how often a player is impacted, an in-ear accelerometer called the DASHR that measures the intensity of jostles to the head, and tests of players’ performance on eye-tracking tasks.

“Right now we are looking on the scale of a season, maybe two seasons,” Eynde said. “What we would like to do in the future is actually follow some of these students throughout their career and get the full data for four years or however long they are involved in the program, and find out more of the long-term effects of what they experience.”

Kara J. Manke, PhD

Post by Kara Manke

Mental Shortcuts, Not Emotion, May Guide Irrational Decisions

If you participate in a study in my lab, the Huettel Lab at Duke, you may be asked to play an economic game. For example, we may give you $20 in house money and offer you the following choice:

  1. Keep half of the $20 for sure
  2. Flip a coin: heads you keep all $20; tails you lose all $20

In such a scenario, most participants choose 1, preferring a sure win over the gamble.

Now imagine this choice, again starting with $20 in house money:

  1. Lose half of the $20 for sure
  2. Flip a coin: heads you keep all $20; tails you lose all $20

In this scenario, most participants prefer the gamble over a sure loss.

If you were paying close attention, you’ll note that both examples are actually numerically identical – keeping half of $20 is the same as losing half of $20 – but changing whether the sure option is framed as a gain or a loss results in different decisions to play it safe or take a risk. This phenomenon is known as the Framing Effect. The behavior that it elicits is weird, or as psychologists and economists would say, “irrational”, so we think it’s worth investigating!

Brain activity when people make choices consistent with (hot colors) or against (cool colors) the Framing Effect.

Brain activity when people make choices consistent with (hot colors) or against (cool colors) the Framing Effect.

In a study published March 29 in the Journal of Neuroscience, my lab used brain imaging data to test two competing theories for what causes the Framing Effect.

One theory is that framing is caused by emotion, perhaps because the prospect of accepting a guaranteed win feels good while accepting a guaranteed loss feels scary or bad. Another theory is that the Framing Effect results from a decision-making shortcut. It may be that a strategy of accepting sure gains and avoiding sure losses tends to work well, and adopting this blanket strategy saves us from having to spend time and mental effort fully reasoning through every single decision and all of its possibilities.

Using functional magnetic resonance imaging (fMRI), we measured brain activity in 143 participants as they each made over a hundred choices between various gambles and sure gains or sure losses. Then we compared our participants’ choice-related brain activity to brain activity maps drawn from Neurosynth, an analysis tool that combines data from over 8,000 published fMRI studies to generate neural maps representing brain activity associated with different terms, just as “emotions,” “resting,” or “working.”

As a group, when our participants made choices consistent with the Framing Effect, their average brain activity was most similar to the brain maps representing mental disengagement (i.e. “resting” or “default”). When they made choices inconsistent with the Framing Effect, their average brain activity was most similar to the brain maps representing mental engagement (i.e. “working” or task”). These results supported the theory that the Framing Effect results from a lack of mental effort, or using a decision-making shortcut, and that spending more mental effort can counteract the Framing Effect.

Then we tested whether we could use individual participants’ brain activity to predict participants’ choices on each trial. We found that the degree to which each trial’s brain activity resembled the brain maps associated with mental disengagement predicted whether that trial’s choice would be consistent with the Framing Effect. The degree to which each trial’s brain activity resembled brain maps associated with emotion, however, was not predictive of choices.

Our findings support the theory that the biased decision-making seen in the Framing Effect is due to a lack of mental effort rather than due to emotions.

This suggests potential strategies for prompting people to make better decisions. Instead of trying to appeal to people’s emotions – likely a difficult task requiring tailoring to different individuals – we would be better off taking the easier and more generalizable approach of making good decisions quick and easy for everyone to make.

Guest post by Rosa Li

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