Category: Cognitive Science/Neuroscience

Scanning people’s brains with fMRI (functional magnetic resonance imaging) was significantly more effective at spotting lies than a traditional polygraph test, researchers in the Perelman School of Medicine at the University of Pennsylvania found in a study published in the Journal of Clinical Psychiatry.

When someone is lying, areas of the brain linked to decision-making are activated, which lights up on an fMRI scan for experts to see. While laboratory studies showed fMRI’s ability to detect deception with up to 90 percent accuracy, estimates of polygraphs’ accuracy ranged wildly, between chance and 100 percent, depending on the study.

The Penn study is the first to compare the two modalities in the same individuals in a blinded and prospective fashion. The approach adds scientific data to the long-standing debate about this technology and builds the case for more studies investigating its potential real-life applications, such as evidence in criminal legal proceedings.

Neuroscientists better than polygraph examiners at detecting deception

Researchers from Penn’s departments of Psychiatry and Biostatistics and Epidemiology found that neuroscience experts without prior experience in lie detection, using fMRI data, were 24 percent more likely to detect deception than professional polygraph examiners reviewing polygraph recordings. In both fMRI and polygraph, participants took a standardized “concealed information” test.*

Polygraph monitors individuals’ electrical skin conductivity, heart rate, and respiration during a series of questions. Polygraph is based on the assumption that incidents of lying are marked by upward or downward spikes in these measurements.

“Polygraph measures reflect complex activity of the peripheral nervous system that is reduced to only a few parameters, while fMRI is looking at thousands of brain clusters with higher resolution in both space and time. While neither type of activity is unique to lying, we expected brain activity to be a more specific marker, and this is what I believe we found,” said the study’s lead author, Daniel D. Langleben, MD, a professor of Psychiatry.

In one example in the paper, fMRI clearly shows increased brain activity when a participant, who picked the number seven, is asked if that is their number. Experts who studied the polygraph counterpart incorrectly identified the number six as the lie. The polygraph associated with the number six shows high peaks after the participant is asked the same questions several times in a row, suggesting that answer was a lie.

The scenario was reversed in another example, as neither fMRI nor polygraph experts were perfect, which is demonstrated in the paper. However, overall, fMRI experts were 24 percent more likely to detect the lie in any given participant.

Combination of technologies was 100 percent correct

Beyond the accuracy comparison, authors made another important observation. In the 17 cases when polygraph and fMRI agreed on what the concealed number was, they were 100 percent correct. Such high precision of positive determinations could be especially important in the United States and British criminal proceedings, where avoiding false convictions takes absolute precedence over catching the guilty, the authors said.

They cautioned that while this does suggest that the two modalities may be complementary if used in sequence, their study was not designed to test combined use of both modalities and their unexpected observation needs to be confirmed experimentally before any practical conclusions could be made.

The study was supported by the U.S. Army Research Office, No Lie MRI, Inc, and the University of Pennsylvania Center for MRI and Spectroscopy.

* To compare the two technologies, 28 participants were given the so-called “Concealed Information Test” (CIT). CIT is designed to determine whether a person has specific knowledge by asking carefully constructed questions, some of which have known answers, and looking for responses that are accompanied by spikes in physiological activity. Sometimes referred to as the Guilty Knowledge Test, CIT has been developed and used by polygraph examiners to demonstrate the effectiveness of their methods to subjects prior to the actual polygraph examination.

In the Penn study, a polygraph examiner asked participants to secretly write down a number between three and eight. Next, each person was administered the CIT while either hooked to a polygraph or lying inside an MRI scanner. Each of the participants had both tests, in a different order, a few hours apart. During both sessions, they were instructed to answer “no” to questions about all the numbers, making one of the six answers a lie.  The results were then evaluated by three polygraph and three neuroimaging experts separately and then compared to determine which technology was better at detecting the fib.

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Abstract of Polygraphy and Functional Magnetic Resonance Imaging in Lie Detection: A Controlled Blind Comparison Using the Concealed Information Test

Objective: Intentional deception is a common act that often has detrimental social, legal, and clinical implications. In the last decade, brain activation patterns associated with deception have been mapped with functional magnetic resonance imaging (fMRI), significantly expanding our theoretical understanding of the phenomenon. However, despite substantial criticism, polygraphy remains the only biological method of lie detection in practical use today. We conducted a blind, prospective, and controlled within-subjects study to compare the accuracy of fMRI and polygraphy in the detection of concealed information. Data were collected between July 2008 and August 2009.

Method: Participants (N = 28) secretly wrote down a number between 3 and 8 on a slip of paper and were questioned about what number they wrote during consecutive and counterbalanced fMRI and polygraphy sessions. The Concealed Information Test (CIT) paradigm was used to evoke deceptive responses about the concealed number. Each participant’s preprocessed fMRI images and 5-channel polygraph data were independently evaluated by 3 fMRI and 3 polygraph experts, who made an independent determination of the number the participant wrote down and concealed.

Results: Using a logistic regression, we found that fMRI experts were 24% more likely (relative risk = 1.24, P < .001) to detect the concealed number than the polygraphy experts. Incidentally, when 2 out of 3 raters in each modality agreed on a number (N = 17), the combined accuracy was 100%.

Conclusions: These data justify further evaluation of fMRI as a potential alternative to polygraphy. The sequential or concurrent use of psychophysiology and neuroimaging in lie detection also deserves new consideration.

In a review of neuroscience literature from more than 200 journals, published in Nature Reviews Neuroscience, a University of British Columbia-led team has proposed a radical new framework for understanding “mind wandering” and mental illness.

Within this framework, spontaneous thought processes — including mind-wandering, creative thinking, and dreaming — arise when thoughts are relatively free from deliberate and automatic constraints. Mind-wandering is not far from creative thinking.

“We propose that mind-wandering isn’t an odd quirk of the mind,” said Kalina Christoff, Ph.D., the review’s lead author and a professor of psychology at UBC. “Rather, it’s something that the mind does when it enters into a spontaneous mode. Without this spontaneous mode, we couldn’t do things like dream or think creatively.”

How mental disorders disrupt mind-wandering and creativity

“Mind-wandering is typically characterized as thoughts that stray from what you’re doing, but we believe this definition is limited,” Christoff said. Instead, mind-wandering happens when thoughts flow freely (that is, when the mind is in its default state).

In contrast, mental disorders, such as anxiety and depression, arise when two types of constraints — automatic and deliberate — disrupt free movement of thoughts and ideas.

“Sometimes the mind moves freely from one idea to another, but at other times it keeps coming back to the same idea, drawn by some worry or emotion,” said Christoff. “Understanding what makes thought free and what makes it constrained is crucial because it can help us understand how thoughts move in the minds of those diagnosed with mental illness.”

The team’s meta-analysis reframes disorders, anxiety, and ADHD, for instance, as extensions of a normal variation in thinking, the researchers explain. The anxious mind helps us focus on what’s personally important, while the ADHD mind is marked by an excessive variability in thought (too much spontaneity).

This new perspective on mind-wandering could help psychologists gain a more in-depth understanding of mental illnesses, said review co-author Zachary Irving, a postdoctoral scholar at the University of California, Berkeley, who has ADHD.

The review was also co-authored by a researcher from Cornell University and one from the University of Colorado Boulder.

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Abstract of Mind-wandering as spontaneous thought: a dynamic framework

Most research on mind-wandering has characterized it as a mental state with contents that are task unrelated or stimulus independent. However, the dynamics of mind-wandering — how mental states change over time — have remained largely neglected. Here, we introduce a dynamic framework for understanding mind-wandering and its relationship to the recruitment of large-scale brain networks. We propose that mind-wandering is best understood as a member of a family of spontaneous-thought phenomena that also includes creative thought and dreaming. This dynamic framework can shed new light on mental disorders that are marked by alterations in spontaneous thought, including depression, anxiety and attention deficit hyperactivity disorder.

Researchers at the Georgia Institute of Technology have developed a “passive haptic learning” (PHL) system that teaches people Morse code within four hours, using a series of vibrations felt near the ear. Participants wearing Google Glass learned it without paying attention to the signals —they played games while feeling the taps and hearing the corresponding letters.

They were 94 percent accurate keying a sentence that included every letter of the alphabet and 98 percent accurate writing codes for every letter.

Georgia Tech researchers used this same method to teach people braille, how to play the piano and improved hand sensation for those with partial spinal cord injury.

The team used Glass for this study because it has both a built-in speaker and tapper (a bone-conduction transducer).

Unconscious learning

In the study, participants played a game while feeling vibration taps between their temple and ear. The taps represented the dots and dashes of Morse code and passively “taught” users through their tactile senses — even while they were distracted by the game.

The taps were created when researchers sent a very low-frequency signal to Glass’s speaker system. At less than 15 Hz, the signal was below hearing range but, because it was played very slowly, the sound was felt as a vibration.

Half of the participants in the study felt the vibration taps and heads a voice prompt for each corresponding letter. The other half — the control group — felt no taps to help them learn.

Participants were tested throughout the study on their knowledge of Morse code and their ability to type it.  After less than four hours of feeling every letter, everyone was challenged to type the alphabet in Morse code in a final test.

The control group was accurate only half the time.  Those who felt the passive cues were nearly perfect.

The method “shows that PHL lowers the barrier to learn text-entry methods — something we need for smartwatches and any text-entry that doesn’t require you to look at your device or keyboard,” said Georgia Tech Professor Thad Starner.

“This research also shows that other common devices with an actuator could be used for passive haptic learning,” he says. “Your smartwatch, Bluetooth headset, fitness tracker or phone.”

The researchers’ next study will go a step further, investigating whether PHL can teach people how to type on a QWERTY keyboard.

The work is supported in part by the National Science Foundation.

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Abstract of Tactile taps teach rhythmic text entry: passive haptic learning of morse code

Passive Haptic Learning (PHL) is the acquisition of sensorimotor skills with little or no active attention to learning. This technique is facilitated by wearable computing, and applications are diverse. However, it is not known whether rhythm-based information can be conveyed passively. In a 12 participant study, we investigate whether Morse code, a rhythmbased text entry system, can be learned through PHL using the bone conduction transducer on Google Glass. After four hours of exposure to passive stimuli while focusing their attention on a distraction task, PHL participants achieved a 94% accuracy rate keying a pangram (a phrase with all the letters of the alphabet) using Morse code on Glass’s trackpad versus 53% for the control group. Most PHL participants achieved 100% accuracy before the end of the study. In written tests, PHL participants could write the codes for each letter of the alphabet with 98% accuracy versus 59% for control. When perceiving Morse code, PHL participants also performed significantly better than control: 83% versus 46% accuracy.

A new theory on how the brain first learns basic math could alter approaches to identifying and teaching students with math-learning disabilities, according to Ben-Gurion University of the Negev (BGU) researchers.

The widely accepted “sense of numbers” theory suggests people are born with a “sense of numbers,” an innate ability to recognize different quantities, and that this ability improves with age. Early math curricula and tools for diagnosing math-specific learning disabilities such as dyscalculia, a brain disorder that makes it hard to make sense of numbers and math concepts, have been based on that consensus.

Other theories suggest that a “sense of magnitude” that enables people to discriminate between different “continuous magnitudes,” such as the density of two groups of apples or total surface area of two pizza trays, is even more basic and automatic than a sense of numbers.

Not just numbers

The new study, published in the Behavioral and Brain Sciences journal, combines these approaches. The researchers argue that understanding the relationship between size and number is what’s critical for the development of higher math abilities. By combining number and size (e.g., area, density, and perimeter), we can make faster and more efficient decisions.

For example: how do you choose the quickest checkout line at the grocery store? While most people intuitively get behind someone with a less filled-looking cart, a fuller-looking cart with fewer, larger items may actually be quicker. The way we make these kinds of decisions reveals that people use the natural correlation between number and continuous magnitudes to compare options — not just numbers.

Other factors, such as language and cognitive control, also play a role in acquiring numerical concepts, they note.

“This new approach will allow us to develop diagnostic tools that do not require any formal math knowledge, thus allowing diagnosis and treatment of dyscalculia before school age,” says Tali Leibovich, PhD, from University of Western Ontario, who led the study.

“If we are able to understand how the brain learns math, and how it understands numbers and more complex math concepts that shape the world we live in, we will be able to teach math in a more intuitive and enjoyable way,” says Leibovich.

The study was supported by the European Research Council under the European Union’s Seventh Framework Programme.

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Abstract of From ‘sense of number’ to ‘sense of magnitude’ – The role of continuous magnitudes in numerical cognition

In this review, we are pitting two theories against each other: the more accepted theory—the ‘number sense’ theory—suggesting that a sense of number is innate and non-symbolic numerosity is being processed independently of continuous magnitudes (e.g., size, area, density); and the newly emerging theory suggesting that (1) both numerosities and continuous magnitudes are processed holistically when comparing numerosities, and (2) a sense of number might not be innate. In the first part of this review, we discuss the ‘number sense’ theory. Against this background, we demonstrate how the natural correlation between numerosities and continuous magnitudes makes it nearly impossible to study non-symbolic numerosity processing in isolation from continuous magnitudes, and therefore the results of behavioral and imaging studies with infants, adults and animals can be explained, at least in part, by relying on continuous magnitudes. In the second part, we explain the ‘sense of magnitude’ theory and review studies that directly demonstrate that continuous magnitudes are more automatic and basic than numerosities. Finally, we present outstanding questions. Our conclusion is that there is not enough convincing evidence to support the number sense theory anymore. Therefore, we encourage researchers not to assume that number sense is simply innate, but to put this hypothesis to the test, and to consider if such an assumption is even testable in light of the correlation of numerosity and continuous magnitudes.

Embryonic neural stem cells transplanted into damaged areas of the visual cortex of adult mice were able to differentiate into pyramidal cells — forming normal synaptic connections, responding to visual stimuli, and integrating into neural networks — researchers at LMU Munich, the Max Planck Institute for Neurobiology in Martinsried and the Helmholtz Zentrum München have demonstrated.

The adult human brain has very little ability to compensate for nerve-cell loss, so biomedical researchers and clinicians are exploring the possibility of using transplanted nerve cells to replace neurons that have been irreparably damaged as a result of trauma or disease, leading to a lifelong neurological deficit.

Previous studies have suggested there is potential to remedy at least some of the clinical symptoms resulting from acquired brain disease through the transplantation of fetal nerve cells into damaged neuronal networks. However, it has not been clear whether transplanted intact neurons could be sufficiently integrated to result in restored function of the damaged network.

Stem-cell-derived neurons mirror connections of damaged neurons

Now, in study published in Nature, the researchers have found that transplanted embryonic nerve cells properly differentiated into pyramidal cells, forming normal synaptic connections, responding to visual stimuli, and carrying out the tasks performed by the damaged cells (videos here).

The researchers were also “astounded” to find that the replacement neurons grew axons throughout the adult brain, reaching proper target areas, and receiving V1-specific (from the primary visual cortex) inputs from host neurons — precisely the same inputs that the original neurons had received.

This includes neocortical circuits that normally never incorporate new neurons in the adult brain.

In addition, after 2–3 months, the transplanted neurons were fully integrated in the brain, showing functional properties indistinguishable from the original neurons.

The study was supported by funding from the German Research Foundation (DFG). 

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Abstract of Transplanted embryonic neurons integrate into adult neocortical circuits

The ability of the adult mammalian brain to compensate for neuronal loss caused by injury or disease is very limited. Transplantation aims to replace lost neurons, but the extent to which new neurons can integrate into existing circuits is unknown. Here, using chronic in vivo two-photon imaging, we show that embryonic neurons transplanted into the visual cortex of adult mice mature into bona fide pyramidal cells with selective pruning of basal dendrites, achieving adult-like densities of dendritic spines and axonal boutons within 4–8 weeks. Monosynaptic tracing experiments reveal that grafted neurons receive area-specific, afferent inputs matching those of pyramidal neurons in the normal visual cortex, including topographically organized geniculo-cortical connections. Furthermore, stimulus-selective responses refine over the course of many weeks and finally become indistinguishable from those of host neurons. Thus, grafted neurons can integrate with great specificity into neocortical circuits that normally never incorporate new neurons in the adult brain.