BrainFacts.org Articles

The Moral Brain

Wed, 15 May 2013 00:00:00 -0400

Neuroscientists don’t pretend to hold the answers as to how people know what is right and what is wrong. But studies show individual biology may influence the ways people process the actions of others.

It turns out we judge others not only for what they do, but also for what we perceive they are thinking while they do it.

Consider the following scenario: Grace and Sally are touring a chemical factory when Grace decides to grab a cup of coffee. Sally asks Grace to pour her a cup as well. Grace spots a container of white powder next to the coffee maker and, knowing that her friend takes sugar in her coffee, she pours some into Sally's cup. As it turns out, the powder is poison, and Sally dies after a few sips.

Most of us would understand and maybe forgive Grace for accidentally poisoning — or even killing — her friend. But what would you think of Grace if you were to learn that she had a hunch that the powder was toxic, yet decided to add it to her friend’s cup anyway?

“Often, what determines moral blame is not what the outcome is, but what [we think] is going on in the mind of the person performing the act,” says Rebecca Saxe, a neuroscientist at the Massachusetts Institute of Technology who studies how the brain casts judgment.

Scientists are learning the ways the brain responds when we attempt to determine right from wrong. Ultimately, they hope such information will help show how the brain processes difficult situations.

What was she thinking?

One way scientists study how we make right-or-wrong judgments is to look at brain regions that are most active when people attempt to interpret the thoughts of others.

In some studies, participants read stories about characters that either accidentally or intentionally cause harm to others while scientists use functional magnetic resonance imaging (fMRI) to track how brain activity changes. Such studies show that thinking about another’s thoughts increases the activity of nerve cells in a brain region known as the right temporo-parietal junction located behind the right ear.

As it turns out, some of these cells respond differently when presented with an intentional harm versus an accident. By zeroing in on the distinct patterns of activity in these cells, Saxe’s group discovered that they could accurately predict how forgiving the participants would be.

“People who say accidents are forgivable have really different [activity] patterns” than those less willing to overlook the unintentional harm, Saxe says.

Thinking about harm

Neuroscientists also study how people respond when asked how they themselves would act in morally challenging scenarios.

In one popular moral dilemma scenario, scientists ask participants to imagine the following: A runaway train is barreling down on five people. The only way to save these people is to hit a switch that would redirect the train onto tracks where it will kill only one person. Would you hit the switch?

What if, instead, you had to push a man off of a bridge to stop the train, knowing that doing so will kill him but save the lives of the others?

Studies ran these scenarios by people with damage to the ventromedial prefrontal cortex — a region believed to be involved in the processing of emotions — and those without damage. Both groups equally support the decision to hit the switch to redirect the train to save more lives.

However, those with damage to the ventromedial prefrontal cortex are much more likely to endorse pushing the man in front of the train, a more direct and personal harm. These studies, led by neuroscientist Antonio Damasio of the University of Southern California, suggest the important role of emotion in the generation of such judgments.

To test how important the ventromedial prefrontal cortex is when we judge the actions of others, Damasio along with neuroscientist Liane Young of Boston asked a small group of people with damage to this region to evaluate variations of the Grace and Sally story.

When told that Grace deliberately puts powder she believes is toxic into Sally’s cup, only to later learn the powder was sugar, healthy adults regularly condemn Grace’s failed attempt to harm her friend. However, people with ventromedial prefrontal cortex damage shrug off Grace’s action. As they see it, as long as Sally survives, Grace’s actions are no big deal.

Damasio says these results, along with others, reveal the role of the ventromedial prefrontal cortex and emotion in evaluating harmful intent.

That’s not fair

There is also evidence that changes in the chemistry of the brain influence how we behave when others treat us unfairly.

To measure how changes in brain chemistry affect people’s reactions to unfairness, University College London neuroscientist Molly Crockett and others gave study participants a drink to drive down levels of the neurotransmitter serotonin in the brain before asking them to play the ultimatum game.

In the ultimatum game, participants are paired with strangers they are told have been given a lump sum of money to share with them. The stranger determines how to divvy up the money, and proposes a split to the participant. The participant decides whether or not to accept the stranger’s offer. If the participant accepts, both players walk away with some money. However, a participant may reject the offer, believing it to be unfair, leaving both players empty-handed. Crockett found that people with lower levels of serotonin were more likely than others to reject offers they deemed to be unfair.

When the scientists examined the brain activity of participants with depleted serotonin levels as they accepted or rejected the offers, they found that rejecting offers led to increased activity in the dorsal striatum — a region involved in processing reward. Crockett says the findings suggest that dips in serotonin can shift people’s motivations to punish unfairness. For instance, when you deplete serotonin, people who are normally more forgiving may become happier with revenge, she says.

Crockett notes that serotonin levels may fluctuate when people are hungry or stressed. The findings illustrate how individual differences in biology might influence the way people view, and respond to, the actions of others.

Our First Anniversary

Tue, 07 May 2013 16:05:00 -0400

To celebrate this milestone, we've put together the most popular articles from each section of the site. Did your favorite article make the list?

Disease-Causing Proteins

Wed, 24 Apr 2013 00:00:00 -0400

Searching for the cause of a rare group of brain diseases revolutionized what scientists know about brain proteins — especially the surprisingly common and complex ways in which they can act in harmful ways. This new understanding, which was made possible by the funding of basic science, may someday lead to improved insights and possibly better treatments for brain diseases in which proteins tend to misfold, including Alzheimer's, Parkinson’s, and Huntington's diseases.

Rare disorders traced to proteins

A group of rare brain diseases may seem like an unlikely place to turn for clues about the estimated 36 million cases of Alzheimer's disease and related dementias worldwide. But, the shocking discovery that a misfolded protein was behind the mysterious disorders known as transmissible spongiform encephalopathies (TSEs) forever changed the way scientists think about proteins and their roles in many neurodegenerative diseases.

The Mystery behind Rare Neurological Disorders

TSEs strike people as well as animals. Creutzfeldt-Jakob disease (CJD) — a rare dementia that affects about one in every one million people each year — is one of the most well-known of the human TSEs. Bovine spongiform encephalopathy (BSE), or “mad cow” disease, and scrapie, a neurological disease that strikes sheep and goats, are also TSEs.

In 1972, after meeting a patient with CJD, neurology resident Stanley Prusiner became determined to uncover the source of the disease. Because studies suggested CJD could be transmitted, many scientists believed a small virus was to blame.

Misfolded Protein Leads to Infection

After a decade of research funded by the National Institutes of Health, Prusiner successfully isolated the agent in question. What he found surprised him: CJD traced back to a single protein. Prusiner named this protein "prion" (combining “protein” and “infectious”).

Scientists were shocked. How could a protein, which lacks genetic instructions, result in changes that cause disease? Many scientists questioned Prusiner’s findings, suggesting instead he had overlooked the true source of the mysterious diseases.

Despite immense skepticism, Prusiner kept at it. In 1984, he and his colleagues shocked scientists again with the discovery that a form of prion protein (PrP) was present in healthy people and animals. As it turns out, prion proteins can fold into two distinct shapes: one is harmless; the other leads to disease (like CJD). Remarkably, the misfolded, disease-causing prions have the ability to "corrupt" the harmless versions, causing them to misfold as well. For this work, Prusiner won the 1997 Nobel Prize in Physiology or Medicine.

Prions play leading role in mad cow outbreak

Just as Prusiner's ideas about prions were beginning to gain traction in the late 1980s, pockets of cattle in the United Kingdom began displaying aggressive behavior, weight loss, and difficulties standing — symptoms indicative of the neurodegenerative illness that would later come to be called mad cow disease.

Mad Cow Traced to Prions

The affected cattle, as it turns out, had consumed prion-infected feed. By the time the animals showed signs of the disease, the infectious prion proteins had been silently corrupting healthy proteins in the brain for some time. As the numbers of healthy proteins converted to the misfolded, disease-causing form, the areas of the brain where the misfolded proteins accumulated began to deteriorate. Scientists believe the mad cow outbreak was amplified and spread by the inclusion of affected animal tissue in the feed offered to healthy animals.

With no cure or ability to detect prions in living people or animals, stopping BSE required extreme steps. Government authorities banned using cattle tissue in feed and ordered the slaughter of older cattle to limit the spread of the disease.

Disease Moves from Animal to Human

Despite significant efforts to contain BSE, some people unknowingly consumed meat from the infected cattle. Research suggests the consumption of beef from cattle with BSE may have led to the emergence of a disease similar to CJD called variant CJD (vCJD) that began striking and killing younger people in the United Kingdom in 1996.

The misfolded prion proteins present in vCJD as well as in other TSEs tend to cluster into thick, compact sheets that are highly resistant to heat, the body's immune system, and even protein-busting enzymes. Clumps of the abnormal proteins can grow in the brain for years without notice. Eventually, this buildup blocks the ability of nerve cells to communicate and causes cell death. Research on the infectious form of prion proteins in prion diseases led scientists to look closely at the role of misfolded proteins in other neurodegenerative diseases.

Future treatments for neurodegenerative disease

Prion diseases aren't the only diseases in which misfolded proteins result in toxic clumps in the brain. In Alzheimer's, Parkinson's, and Huntington's diseases, plaques and tangles made up of different types of protein also build up, leading to nerve cell death.

New research suggests that the proteins in these diseases, while different than prions, share similarities with the misfolded, disease-causing proteins. For example, some animal studies show that the beta-amyloid protein, which is associated with Alzheimer's disease, can corrupt other proteins and cause new protein plaques to form when injected into the brain.

Scientists hope that efforts to uncover how disease-causing proteins corrupt healthy proteins in prion diseases and Alzheimer’s disease will inform future treatments for slowing the progression of neurodegenerative conditions.

Mystery Propels More Research

Even after decades of research, prions remain highly mysterious. Scientists continue to search for answers as to why some prion diseases arise spontaneously and the mechanism the misfolded proteins use to induce healthy cellular proteins into the misfolded, disease-causing form.

Scientists know that normal, healthy prion protein (PrP) has an important function, but specific information about its role remains elusive. Mice bred to lack PrP are immune to prion diseases, but show only subtle neurological changes, for instance. Recent evidence suggests that PrP may help protect nerve cells during stress or disease, and assist with the formation of new connections, or synapses, between brain cells, which are essential to learning and memory.

When Prusiner first set out to identify the agent responsible for the rare, but deadly prion diseases, little did he know his findings would have health implications far beyond, as is often the case with basic research. Sustained funding from NIH, the National Science Foundation, and the U.S. Department of Agriculture continues to be vital to scientists’ quest to understand the events that lead to protein misfolding in the brain and develop new therapies for the millions of people worldwide suffering from neurodegenerative diseases.

Is photographic memory real? If so, how does it work?

Wed, 17 Apr 2013 00:00:00 -0400

New Educator Resources Added

Thu, 11 Apr 2013 15:16:00 -0400

Teaching opportunities are everywhere, from a science club to a classroom.

Here, we provide 75 easy-to-use teaching resources and activities to engage young people’s interest, and educational tools sorted by age and reading level. Most resources in this section are aimed at pre-university students. Multimedia resources include videos and images to augment lesson plans.

In our committment to science education, we have added 25 new educators resources to the site.

If you have a website you'd like to be considered as a future educator resource, please send it to baw@sfn.org.

Sheep Brain Dissections

Thu, 11 Apr 2013 15:07:00 -0400

Dissection is one of the most fun and educational approaches to science, and one of the best ways for students to gain an appreciation of the three dimensional constriction of the brain. Dissect a real brain with your students with this sheep brain dissection guide.

Access Sheep Brain Dissections from the University of New England's Center for Excellence in the Neurosciences.

Kids 4 Research: Kids

Thu, 11 Apr 2013 12:42:00 -0400

Animals are a huge part of our daily lives, providing us with food, clothing, and companionship. Animals also serve an important role in research. This website shows you how animals help scientists in research — and how research, in turn, helps animals.

Access Kids 4 Research: Kids from Kids 4 Research.

Kids 4 Research: Teens

Thu, 11 Apr 2013 12:39:00 -0400

Animals are a huge part of our daily lives, providing us with food, clothing, companionship, and disability assistance. Animals also serve an important role in research. This website shows you how animals help scientists in research — and how research, in turn, helps animals.

Access Kids 4 Research: Teens from Kids 4 Research.

Kids 4 Research: Teachers

Thu, 11 Apr 2013 12:36:00 -0400

Animals are a huge part of our daily lives, providing us with food, clothing, and companionship. Animals also serve an important role in research. This website provides information to students, teachers, and parents on responsible laboratory animal care and use in biomedical research, testing, and education.

Access Kids 4 Research: Teachers from Kids 4 Research.

Auditory Neuroscience: Making Sense of Sound

Thu, 11 Apr 2013 12:21:00 -0400

How does the brain decipher voices from music, and location from sound? What would it be like to have a cochlear implant? Explore these questions and more with sound examples, color figures, and animations.

Access Auditory Neuroscience: Making Sense of Sound from Jan Schnupp and Andrew King (University of Oxford), and Eli Nelken (Hebrew University of Jerusalem).

Alzheimer's Disease: Just for Kids and Teens

Thu, 11 Apr 2013 12:17:00 -0400

Does a friend or family member you know have Alzheimer’s disease? This page provides resources to help learn about Alzheimer’s disease and understand how it affects people. Alzheimer’s changes the lives of everyone it touches.

Access Just for Kids and Teens from the Alzheimer's Association.

The Forgetting: Lesson Plans for Educators

Wed, 10 Apr 2013 17:04:00 -0400

The Forgetting: A Portrait of Alzheimer's is a documentary on Alzheimer’s disease. This site provides three lesson plans designed for grades 9-12 educators in science, social studies, and language arts classes. The lesson plans can be used in conjunction with The Forgetting program or as stand-alone resources.

Access The Forgetting: Lesson Plans for Educators from PBS.

Speaking Honestly – Animal Research Education

Wed, 10 Apr 2013 16:58:00 -0400

A program designed to guide educators in leading a discussion-based classroom activity on the different views on the use of animals in research. The founders saw a great need to provide the public with factual information rather than sensationalized stories that often grab the attention of young people and facilitate common misconceptions about the use of animals in research.

Access Speaking Honestly – Animal Research Education.

Sleep Memory Connection

Wed, 10 Apr 2013 16:56:00 -0400

What happens in your brain as you cycle through the various stages of sleep, and how does this activity affect learning and memory? Use this interactive guide to explore what scientists are learning about REM (rapid-eye movement) sleep, and explore recent research linking sleep—and sleep deprivation—to different types of memories.

Access Sleep Memory Connection at NOVA.

Phantom Limbs

Wed, 10 Apr 2013 16:55:00 -0400

In cases of phantom limbs, amputees and even those born without one or more limbs feel pain and other sensations in their missing body parts. Explore six interactive cases with neuroscientist V.S. Ramachandran's vivid descriptions of his experiences with phantom-limb patients and how he managed to help them.

Access Phantom Limbs at NOVA.

Goosebumps: The Science of Fear

Wed, 10 Apr 2013 16:52:00 -0400

Experience fear in a safe and fun environment, and learn about the science behind fear as well as the emotional response involved. This website is built as a walkthrough of the activities at a science museum exhibit on fear, but contains the details to build your own science of fear exhibit.

Access Goosebumps: The Science of Fear from the California Science Center.

Fear and the Brain

Wed, 10 Apr 2013 16:50:00 -0400

Fear is a full-body experience. While the brain does the brunt of the processing and coordination work, the entire body quickly gets involved to create the fear response. Learn about important brain areas and pathways involved, and how they affect the body.

Access Fear and the Brain from the California Science Center.

Brain Trauma

Wed, 10 Apr 2013 16:48:00 -0400

Knocks to the head may seem funny in cartoons and YouTube videos, but even minor head injuries often lead to serious concussions. A concussion may leave no external trace yet cause permanent memory loss, attention problems, and depression. This NOVA scienceNOW video investigates promising new leads in understanding this puzzling condition, which affects millions of people in the United States, including many student athletes.

Access Brain Trauma at NOVA.

Erich Jarvis: Connecting Birdsong to Human Speech

Wed, 10 Apr 2013 00:00:00 -0400

Jarvis’ research aims to reveal how the brain learns and generates vocalizations, such as speech. Such studies may one day shed light on the evolution and mechanisms of spoken language in humans, and the causes of speech disorders.

Jarvis is the recipient of numerous awards for his research, including the Alan T. Waterman Award, the National Science Foundation's highest honor for a young researcher, and the National Institutes of Health Director's Pioneer Award. For nearly four years Jarvis has served as the program director of the Society for Neuroscience’s Neuroscience Scholars Program, a three-year fellowship that provides career development and professional opportunities for underrepresented and diverse undergraduate students, graduate students, and postdoctoral fellows in neuroscience. Over the course of his career, Jarvis has mentored hundreds of young neuroscientists.

What do you study in your lab?

I study vocal learning (sound imitation) in animals, particularly song learning birds. You can think of vocal learning as the foundation of human language. While there are some big differences between human language and birdsong, there is also a great deal of similarity in the pathways the brain uses to learn and produce vocal sounds.

By studying vocal learning birds, including those that can imitate human speech, such as parrots, we can find the essential brain pathways, genes, and behaviors that are necessary for this trait.

How common is vocal learning?

It's actually a pretty rare trait. The sounds most animals make are innate, which means they are limited in their ability to alter them or mimic other sounds.

Six months ago I would have told you that the only vocal learners were songbirds, parrots, and hummingbirds amongst birds, and dolphins, bats, elephants, sea lions, and humans amongst mammals. But recent research, including studies in our lab, suggests different species, including mice, may have the ability to imitate sound to different degrees.

How are the brains of vocal learners different from other animals?

Vocal learners all have a connection, or pathway, between neurons in the forebrain — a brain region that helps control vocal learning — and neurons in the brainstem, which control the muscles involved in producing innate vocalizations. When we look at these pathways across vocal learners, we see that they're very similar, even though these species are only distantly related to one another.

How did learning evolve in such distantly related species?

In the songbird, the evidence suggests that the brain centers involved in vocal learning evolved from a motor control pathway. What separates vocal learners and non-learners could have been a genetic mutation that occurred in the learners that controls the connection of the forebrain vocal learning pathways to the brainstem motor neurons that control vocal production. This would explain how vocal learning could arise in distantly related animals.

What methods do you use to answer these questions?

Answering questions about the mechanisms of spoken language or how vocal learning evolved requires attacking the question from multiple angles, including using the tools and techniques in the fields of genetics, cell biology, and anatomy.

If I have a question, I’m going to find whatever means I can to answer it. Getting the big science done requires collaboration.

In addition to your research, you are known for your active role in the Neuroscience Scholars Program (NSP), which aims to increase the likelihood that diverse trainees who enter the neuroscience field continue to advance in their careers. What sorts of challenges do minorities in the sciences face?

I think there are several main types of challenges that minorities face, which I learned from my own personal experience as an African American and part Native American. One challenge is more internal — you have to have strong enough self-esteem to believe you are where you are because of your abilities and qualifications alone, as well as the confidence to go after what you want. The other type of challenge is external, as minorities often face the unconscious biases from others, including faculty and mentors.

What can be done to overcome these challenges?

We've got to get rid of both the internal and external biases. To do this requires a lot more mentoring, a lot more sensitivity training of faculty and others who are doing the mentoring of young minorities in the sciences, and a village of support. Once you have these things in place, I think we'll have a much greater impact.

It's been shown time and again if you have a culturally diverse workforce, everyone benefits. Everyone will make more advancements and be more successful. I've seen that in my own lab, which tends to be diverse not only in the techniques that we use but in the people that come to it.

Image of the Week: An Inverted Mystery

Fri, 05 Apr 2013 00:00:00 -0400

Our brains have a spectacular ability to recognize faces. Minimal information is required to do so — for example, a nose, a mouth, and two eyes. In the first image above, there isn’t quite enough distinguishing information for most people to see a face. However, when the image is inverted (the second image above), a face appears. This results because our brain is tuned to seeing faces in this orientation.

Designing Brain-Based Robots

Wed, 27 Mar 2013 00:00:00 -0400

Scientists are constructing models that simulate what goes on inside the human brain to help better understand how the brain works and discover new ways to create computers that act more like humans.

Although the brain is sometimes compared to a computer, scientists working to build such models are quick to point out the differences between the two.

Hardware, software differences

For starters, the brain isn’t wired like a computer, says theoretical neuroscientist Chris Eliasmith, of the University of Waterloo, in Ontario.

“One way to describe the difference between digital computers and the brain is in terms of the architecture,” he says. “That is, in how the components are arranged and what each of the components do.”

While the hardware of a computer is an elaborate collection of electric on-off switches, brain cell communication is more variable. Sometimes a cell will send a chemical message across a synapse — the junction between cells — and sometimes it won’t. Instead of treating all incoming signals alike, as a digital circuit does, neurons can give added weight to pulses coming from a favorite source. This flexibility allows the brain to be less precise in its calculations, but more energy efficient than a computer, because it doesn’t require as much energy per computation.

Unlike a computer, your brain is capable of continuously changing, or updating its hardware, in response to new experiences. Over time, the connections between some brain cells are strengthened, and in some cases, cells can be added or removed. Computers don’t have this kind of flexibility. While updated software can instruct computers to perform in different ways, their hardware is unchanging.

Brains and computers both store and retrieve information, but they go about doing it in different ways. Computers typically run a single software program that has access to all the memory inside the computer. In the brain, no single nerve cell has access to all information. Instead, individual cells communicate with hundreds of nearby cells to access information. Millions of nerve cells combine signals simultaneously, forming circuits to process information or plan a sequence of actions.

A more human model

In recent years, the way in which systems of neurons in the brain interact as a network has become the inspiration for massive parallel-processing architectures and models that process information in human-like ways.

Eliasmith designed a large-scale computer model he named Spaun (short for Semantic Pointer Architecture Unified Network). Using about 2.5 million simulated “nerve cells” that mimic some of the brain’s physiological properties, a simulated eye that sees, and an arm that draws, Spaun is able to recognize, process, and jot down numbers and lists of items when commanded.

Models such as Spaun empower scientists to screen theories about how the brain directs information through itself, Eliasmith says.

“Because we have access to all of the data that the model generates, we can record activity patterns that occur as [the model] performs various functions. We can then look in a real brain to see if the patterns of activity are similar across the two.”

Learning from experience

At the Technical University of Munich, researchers are designing mobile robots that can see, move, and lift objects. The scientists are developing models — that run on massive parallel processors — that allow the robots to learn concepts that have not been pre-programmed based on their sensory experience.

“Humans do this naturally all the time,” says Jörg Conradt, a neuroscientist working on the project. “We fuse information from what we see and how we move with what our sensory systems tell us.”

Over the past two years, the team has seen signs the robots can modify their behaviors in response to changes in the environment. In one study, a robot learned to adjust its position when lifting a glass, based on how much water was in the glass. Another study found near-sighted robots learned to move closer to objects for observation, just as people would, to make up for their shortsighted camera-eye.

“In the near future I expect we’ll see more adaptive, flexible robots, that can survive in a human world, not only in an environment that is prepared for robots,” Conradt says.

Information on the workings of such robots will also provide a better understanding of fundamental computing principles performed in brains, he adds.

Living Laboratories

Wed, 20 Mar 2013 16:17:00 -0400

Fruit flies and other model organisms permit scientists to investigate questions that would not be possible to study in any other way. These living systems are, relatively speaking, simple, inexpensive, and easy to work with. Model organisms are indispensable to science because creatures that appear very different from us and from one another actually have a lot in common when it comes to body chemistry.

Access Living Laboratories from the National Institute of General Medical Science.

The Truth About Lies: The Science of Deception

Wed, 20 Mar 2013 00:00:00 -0400

Regardless of why we choose to lie, scientists want to understand how the brain works when we stretch the truth. By analyzing the changes that take place in the brain when we deceive, scientists hope to learn more about the process of lying and, ultimately, how to detect it.

Lying in the laboratory

Scientists believe that a lie is made up of two parts: a person must create the lie and also withhold the truth.

To study deception in a laboratory setting, scientists create a variety of situations in which people are asked to lie. One popular test is the ‘mock theft’ paradigm, where each volunteer is told to take one of two items, such as a ring or watch, from a room and hide it in a locker. The volunteer is also instructed to deny having either item (a lie in one case and a truth in the other) during subsequent questioning.

Before questioning begins, electrodes are placed on the participant’s scalp. The electrodes record event-related potentials, which measure electrical signals on the surface of the brain. Such signals can provide clues about how the brain performs during lying and truth-telling. However, because this technique measures the activity of large brain regions, it is not suited to identify the exact brain areas involved when telling a lie.

Over the last decade, scientists have used functional magnetic resonance imaging (fMRI) to more accurately locate regions of the brain that change when a person lies. This technique measures changes in blood flow in the brain — a reflection of neural activity — as people answer questions while inside of a scanner. The resulting images pinpoint brain activity in specific regions during the lie and truth phases of the deception paradigms.

Regions of deceit

Although several brain areas appear to play a role in deception, the most consistent finding across multiple fMRI studies is that activity in the prefrontal cortex increases when people lie. The prefrontal cortex, situated just behind the forehead, is a collection of regions responsible for executive control (the ability to regulate thoughts or actions to achieve goals). Executive control includes cognitive processes such as planning, problem solving, and attention — all important components of deception — so it’s no surprise the prefrontal cortex is active when we lie. Dishonesty requires the brain to work harder than honesty, and this effort is reflected by increased brain activity. Studies even show people take longer to respond when lying.

While lies lead to greater activity in the prefrontal cortex, so do many everyday tasks, such as cooking dinner or playing a game of chess, explains Josh Greene, who studies moral judgment and decision-making at Harvard University. “It’s not like there’s some ‘lying’ part of the brain” that is only involved in deception, he says.

Most neuroimaging studies of deception have examined this behavior in healthy people, so information about how the brains of people who lie compulsively differ from healthy people remains largely unknown.

fMRI for lie detection?

Even without a clear ‘lying’ region, researchers can use fMRI to detect when a study participant is telling a lie in the laboratory with about 85 percent accuracy (polygraph tests, which measure changes in blood pressure, skin conductivity, and respiration during questioning, produce similar accuracy in the laboratory setting). Even with such a high rate of accuracy, however, use of fMRI and polygraph tests to identify deceit outside of the laboratory is controversial.

Two U.S. companies market fMRI lie detection commercially and a few court cases around the world have considered using it as evidence. But both have received much opposition from the neuroscience community.

How closely do laboratory paradigms model real-world lies? Not very closely, says Stanford University’s Anthony Wagner, who studies memory and has testified in court against the validity of fMRI lie detection. As Wagner explains, laboratory studies involve instruction to tell a low-stakes lie about an action they recently performed. However, in the real world, lies are self-generated, often high risk and emotionally charged, and lie detection may occur years after the event in question.

Another issue that has not been adequately studied, Wagner says, is how countermeasures, such as small movements, changes in breathing, or altered cognitive processing, can affect the accuracy of fMRI lie detection. By using countermeasures, a person may be able to deliberately offset any brain changes associated with deception to defeat lie detection technology. A recent study found the accuracy of fMRI for lie detection dropped to a mere 33 percent when participants used countermeasures during questioning.

As neuroscientists like Wagner and University of Plymouth professor Giorgio Ganis see it, right now there isn’t enough evidence to support the use of fMRI for lie detection.

“Any application of this technique in the real world is premature,” says Ganis, who studies deception using brain imaging. However, with more sophisticated analysis and technology development, he concedes there may one day be a future for accurately detecting deception.

Learning and Memory

Tue, 19 Mar 2013 12:12:00 -0400

Although you may assume that what you see is what your eyes see and send to the brain, our brain cells actually have to work together to sort and prioritize information. Learn how our brain interprets and remembers the sensory information it receives with this lesson plan. Three hands-on activities show students the Stroop effect, the blind spot, and the role of repetition in memory.

Access Learning and Memory from the University of New England's Center for Excellence in the Neurosciences.

Neurological Disorders

Tue, 19 Mar 2013 12:12:00 -0400

Although some neurological disorders are quite common, such as migraines and Alzheimer’s disease, understanding their effects on the brain can be a challenge. This lesson plan has two hands-on activities to demonstrate some of the symptoms of a few neurological diseases.

Access Neurological Disorders from the University of New England's Center for Excellence in the Neurosciences.

Neuroscience in the Classroom