Posts tagged emotion
Posts tagged emotion
Testosterone, a steroid hormone, is well known to contribute to aggressive behavior in males, but the neural circuits through which testosterone exerts these effects have not been clear.
Prior studies found that the administration of a single dose of testosterone influenced brain circuit function. Surprisingly, however, these studies were conducted exclusively in women.
Researchers, led by Dr. Justin Carré, sought to rectify this gap by conducting a study of the effects of testosterone on the brain’s response to threat cues in healthy men.
They focused their attention on brain structures that mediate threat processing and aggressive behavior, including the amygdala, hypothalamus, and periaqueductal gray.
The researchers recruited 16 healthy young male volunteers, who completed two test days on which they received either testosterone or placebo. On both testing days, the men first received a drug that suppressed their testosterone. This step ensured that testosterone levels were similar among all study participants. The amount of testosterone administered in this study only returned testosterone levels to the normal range. Subjects then completed a face-matching task while undergoing a functional magnetic resonance imaging scan.
Data analyses revealed that, compared with placebo, testosterone increased reactivity of the amygdala, hypothalamus and periaqueductal grey when viewing angry facial expressions.
"We were able to show for the first time that increasing levels of testosterone within the normal physiological range can have a profound effect on brain circuits that are involved in threat-processing and human aggression," said Carré, Assistant Professor at Nipissing University.
"Understanding testosterone effects on the brain activity patterns associated with threat and aggression may help us to better understand the ‘fight or flight’ response in males that may be relevant to aggression and anxiety," commented Dr. John Krystal, Editor of Biological Psychiatry.
Expanding our knowledge of exactly how testosterone affects the male brain is particularly important, as testosterone augmentation has become increasingly promoted and aggressively marketed as a solution to reduced virility in aging men. Further work is indeed continuing, Carré said. “Our current work is examining the extent to which a single administration of testosterone influences aggressive and competitive behavior in men.”
People choosing between two or more equally positive outcomes experience paradoxical feelings of pleasure and anxiety, feelings associated with activity in different regions of the brain, according to research led by Amitai Shenhav, an associate research scholar at the Princeton Neuroscience Institute at Princeton University.
In one experiment, 42 people rated the desirability of more than 300 products using an auction-like procedure. Then they looked at images of paired products with different or similar values and were asked to choose between them. Their brain activity was scanned using functional magnetic resonance imaging (fMRI). After the scan, participants reported their feelings before and during each choice. They received one of their choices at the end of the study.
Choices between two highly valued items (high-high), such as a digital camera and a camcorder, were associated with the most positive feelings and the greatest anxiety, compared with choices between items of low value (low-low), like a desk lamp and a water bottle, or between items of different values (low-high). Functional MRI scans showed activity in two regions of the brain, the striatum and the prefrontal cortex, both known to be involved in decision-making. Interestingly, lower parts of both regions were more active when subjects felt excited about being offered the choice, while activity in upper parts was strongly tied to feelings of anxiety.
This evidence that parallel brain circuits are associated with opposing emotional reactions helps to answer a puzzling question, according to Shenhav: “Why isn’t our positivity quelled by our anxiety, or our anxiety quelled by the fact that we’re getting this really good thing at the end? This suggests that it’s because these circuits evolved for two different reasons,” he said. “One of them is about evaluating the thing we’re going to get, and the other is about guiding our actions and working out how difficult the choice will be.”
The study, “Neural correlates of dueling affective reactions to win-win choices,” was published July 14 in the Proceedings of the National Academy of Sciences. Shenhav conducted the research as a graduate student at Harvard University, along with Professor of Psychology and Neuroscience Randy Buckner, the study’s senior author.
A second fMRI experiment showed that the same patterns of emotional reactions and brain activity persisted even when the participants were told before each choice how similarly they had valued the items. Their anxiety didn’t abate, despite knowing how little they stood to lose by making a “wrong” choice. In a third experiment, Shenhav and Buckner tested whether giving people more than two choices increased their levels of anxiety. Indeed, they found that providing six options led to higher levels of anxiety than two options, particularly when all six of the options were highly valued items. But positive feelings about being presented with the choice were similar for two or six options.
This suggests that the anxiety stems from the conflict of making the decision, rather than the opportunity cost of the choice — an economic concept that refers to the lost value of the second-best option. The opportunity cost should be the same, regardless of the number of choices. In addition, subjects in this final study were given an unlimited amount of time to make a decision, compared with 1.5 seconds in the first two studies. The results showed that time pressure was not the main source of anxiety during the choices.
At the end of each study, participants had a surprise opportunity to reverse their earlier choices. Higher activity in a part of the brain called the anterior cingulate cortex around the time of an initial choice predicted whether that decision would later be reversed. Previous work has shown that this brain region is involved in assessing how conflicted an individual feels over a particular choice; this result suggests that some choices may have continued to elicit conflict after the participant made a decision, Shenhav said. The researchers also found that people who reported more anxiety in their daily lives were more likely to change their minds.
This work could explain why ostensibly positive options can evoke a mixture of positive and negative responses, which are not explained by purely economic analyses of choice. “Rationally, there’s no reason why when you put one good thing with another good thing, you should feel worse about the situation,” said Brian Knutson, an associate professor of psychology and neuroscience at Stanford University, who is familiar with the work but was not involved in it. “The neuroimaging tells us that these different mechanisms are fighting with each other,” he said. “Understanding that dynamic can help us understand why decisions that we think should make us feel better can actually make us feel worse.”
According to Shenhav, this research could shed light on the neural processes that can make more momentous choices so paralyzing for some people — for instance, deciding where to go to college or which job offer to take. But he admits that even more trivial decisions can be tough for him. “I probably experience more win-win choice anxiety than the average person,” he said. “I’m even terrible at choosing where to eat dinner.”
(Image caption:This is an overall fMRI composite comparison of the brains of highly sensitive people (HSP) compared to non-HSPs. The areas in color represent some of the regions of the brain where greater activation occurs in HSPs compared to non-HSPs. The brain region highly associated with empathy and noticing emotion (Anterior Insula) shows significantly greater activation in HSPs than non-HSPs when viewing a photo of their partner smiling. Credit: Art Aron)
Do you jump to help the less fortunate, cry during sad movie scenes, or tweet and post the latest topics and photos that excite or move you? If yes, you may be among the 20 percent of our population that is genetically pre-disposed to empathy, according to Stony Brook University psychologists Arthur and Elaine Aron. In a new study published in Brain and Behavior, Drs. Aron and colleagues at the University of California, Albert Einstein College of Medicine, and Monmouth University found that Functional Magnetic Resonance Imaging (fMRI) of brains provide physical evidence that the “highly sensitive” brain responds powerfully to emotional images.
Previous research suggests that sensory processing sensitivity (SPS) is an innate trait associated with greater sensitivity, or responsiveness, to environmental and social stimuli. According to Dr. Arthur Aron, the trait is becoming increasingly associated with identifiable behaviors, genes, physiological reactions, and patterns of brain activation. Highly sensitive people (HSP), those high in SPS, encompass roughly 20 percent of the population. Elaine Aron, PhD, originated the HSP concept. Humans characterized as HSPs tend to show heightened awareness to subtle stimuli, process information more thoroughly, and be more reactive to both positive and negative stimuli. In contrast, the majority of people have comparatively low SPS and pay less attention to subtle stimuli, approach situations more quickly and are not as emotionally reactive.
In “The Highly Sensitive Brain: An fMRI study of Sensory Processing Sensitivity and Response to Others’ Emotions,” Drs. Aron and colleagues used fMRI brain scans to compare HSPs with low SPS individuals. The analysis is the first with fMRI to demonstrate how HSPs’ brain activity processes others’ emotions.
The brains of 18 married individuals (some with high and some with low SPS) were scanned as they viewed photos of either smiling faces, or sad faces. One set of photos included the faces of strangers, and the other set included photos of their husbands or wives.
“We found that areas of the brain involved with awareness and emotion, particularly those areas connected with empathetic feelings, in the highly sensitive people showed substantially greater blood flow to relevant brain areas than was seen in individuals with low sensitivity during the twelve second period when they viewed the photos,” said Dr. Aron, a Research Professor in Psychology at Stony Brook. “This is physical evidence within the brain that highly sensitive individuals respond especially strongly to social situations that trigger emotions, in this case of faces being happy or sad.”
The brain activity was even higher when HSPs viewed the expressions of their spouses. The highest activation occurred when viewing images of their partner as happy. Most of the participants were scanned again one year later, and the same results occurred.
Areas of the brain indicating the greatest activity – as shown by blood flow – include sections known as the “mirror neuron system,” an area strongly associated with empathetic response and brain areas associated with awareness, processing sensory information and action planning.
Dr. Aron believes the results provide further evidence that HSPs are generally highly tuned into their environment. He said the new findings via the fMRI provide evidence that especially high levels of awareness and emotional responsiveness are fundamental features of humans characterized as HSPs.
The amygdala is a key “fear center” in the brain. Alterations in the development of the amygdala during childhood may have an important influence on the development of anxiety problems, reports a new study in the current issue of Biological Psychiatry.
Researchers at the Stanford University School of Medicine recruited 76 children, 7 to 9 years of age, a period when anxiety-related traits and symptoms can first be reliably identified. The children’s parents completed assessments designed to measure the anxiety levels of the children, and the children then underwent non-invasive magnetic resonance imaging (MRI) scans of brain structure and function.
The researchers found that children with high levels of anxiety had enlarged amygdala volume and increased connectivity with other brain regions responsible for attention, emotion perception, and regulation, compared to children with low levels of anxiety. They also developed an equation that reliably predicted the children’s anxiety level from the MRI measurements of amygdala volume and amygdala functional connectivity.
The most affected region was the basolateral portion of the amygdala, a subregion of the amygdala implicated in fear learning and the processing of emotion-related information.
“It is a bit surprising that alterations to the structure and connectivity of the amygdala were so significant in children with higher levels of anxiety, given both the young age of the children and the fact that their anxiety levels were too low to be observed clinically,” commented Dr. Shaozheng Qin, first author on this study.
Dr. John Krystal, Editor of Biological Psychiatry, commented, “It is critical that we move from these interesting cross-sectional observations to longitudinal studies, so that we can separate the extent to which larger and better connected amygdalae are risk factors or consequences of increased childhood anxiety.”
“However, our study represents an important step in characterizing altered brain systems and developing predictive biomarkers in the identification for young children at risk for anxiety disorders,” Qin added. “Understanding the influence of childhood anxiety on specific amygdala circuits, as identified in our study, will provide important new insights into the neurodevelopmental origins of anxiety in humans.”
Pregnant women show increased activity in the area of the brain related to emotional skills as they prepare to bond with their babies, according to a new study by scientists at Royal Holloway, University of London.
The research, which will be presented at the British Psychological Society’s annual conference today (Wednesday 7 May), found that pregnant women use the right side of their brain more than new mothers do when they look at faces with emotive expressions.
“Our findings give us a significant insight into the ‘baby brain’ phenomenon that makes a woman more sensitive during the child bearing process”, said Dr Victoria Bourne, from the Department of Psychology at Royal Holloway. “The results suggest that during pregnancy, there are changes in how the brain processes facial emotions that ensure that mothers are neurologically prepared to bond with their babies at birth.”
Researcher examined the neuropsychological activity of 39 pregnant women and new mothers as they looked at images of adult and baby faces with either positive or negative expressions. The results showed that pregnant women used the right side of their brain more than new mothers, particularly when processing positive emotions.
The study used the chimeric faces test, which uses images made of one half of a neutral face combined with one half of an emotive face to see which side of the participants’ brain is used to process positive and negative emotions.
Dr Bourne said: “We know from previous research that pregnant women and new mothers are more sensitive to emotional expressions, particularly when looking at babies’ faces. We also know that new mothers who demonstrate symptoms of post-natal depression sometimes interpret their baby’s emotional expressions as more negative than they really are.
“Discovering the neuropsychological processes that may underpin these changes is a key step towards understanding how they might influence a mother’s bonding with her baby.”
Neuroscientists have discovered a brain pathway that underlies the emotional behaviours critical for survival.
New research by the University of Bristol, published in the Journal of Physiology, has identified a chain of neural connections which links central survival circuits to the spinal cord, causing the body to freeze when experiencing fear.
Understanding how these central neural pathways work is a fundamental step towards developing effective treatments for emotional disorders such as anxiety, panic attacks and phobias.
An important brain region responsible for how humans and animals respond to danger is known as the PAG (periaqueductal grey), and it can trigger responses such as freezing, a high heart rate, increase in blood pressure and the desire for flight or fight.
This latest research has discovered a brain pathway leading from the PAG to a highly localised part of the cerebellum, called the pyramis. The research went on to show that the pyramis is involved in generating freezing behaviour when central survival networks are activated during innate and learnt threatening situations.
The pyramis may therefore serve as an important point of convergence for different survival networks in order to react to an emotionally challenging situation.
Dr Stella Koutsikou, first author of the study and Research Associate in the School of Physiology and Pharmacology at the University of Bristol, said: “There is a growing consensus that understanding the neural circuits underlying fear behaviour is a fundamental step towards developing effective treatments for behavioural changes associated with emotional disorders.”
Professor Bridget Lumb, Professor of Systems Neuroscience, added: “Our work introduces the novel concept that the cerebellum is a promising target for therapeutic strategies to manage dysregulation of emotional states such as panic disorders and phobias.”
The researchers involved in this work are all members of Bristol Neuroscience which fosters interactions across one of the largest communities of neuroscientists in the UK.
Professor Richard Apps said: “This is a great example of how Bristol Neuroscience brings together expertise in different fields of neuroscience leading to exciting new insights into brain function.”
Older people who have apathy but not depression may have smaller brain volumes than those without apathy, according to a new study published in the April 16, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology. Apathy is a lack of interest or emotion.
“Just as signs of memory loss may signal brain changes related to brain disease, apathy may indicate underlying changes,” said Lenore J. Launer, PhD, with the National Institute on Aging at the National Institutes of Health (NIH) in Bethesda, MD, and a member of the American Academy of Neurology. “Apathy symptoms are common in older people without dementia. And the fact that participants in our study had apathy without depression should turn our attention to how apathy alone could indicate brain disease.”
Launer’s team used brain volume as a measure of accelerated brain aging. Brain volume losses occur during normal aging, but in this study, larger amounts of brain volume loss could indicate brain diseases.
For the study, 4,354 people without dementia and with an average age of 76 underwent an MRI scan. They were also asked questions that measure apathy symptoms, which include lack of interest, lack of emotion, dropping activities and interests, preferring to stay at home and having a lack of energy.
The study found that people with two or more apathy symptoms had 1.4 percent smaller gray matter volume and 1.6 percent less white matter volume compared to those who had less than two symptoms of apathy. Excluding people with depression symptoms did not change the results.
Gray matter is where learning takes place and memories are stored in the brain. White matter acts as the communication cables that connect different parts of the brain.
“If these findings are confirmed, identifying people with apathy earlier may be one way to target an at-risk group,” Launer said.
What’s one of your worst memories? How did it make you feel? According to psychologists, remembering the emotions felt during a negative personal experience, such as how sad you were or how embarrassed you felt, can lead to emotional distress, especially when you can’t stop thinking about it.
When these negative memories creep up, thinking about the context of the memories, rather than how you felt, is a relatively easy and effective way to alleviate the negative effects of these memories, a new study suggests.
Researchers at the Beckman Institute at the University of Illinois, led by psychology professor Florin Dolcos of the Cognitive Neuroscience Group, studied the behavioral and neural mechanisms of focusing away from emotion during recollection of personal emotional memories, and found that thinking about the contextual elements of the memories significantly reduced their emotional impact.
“Sometimes we dwell on how sad, embarrassed, or hurt we felt during an event, and that makes us feel worse and worse. This is what happens in clinical depression—ruminating on the negative aspects of a memory,” Dolcos said. “But we found that instead of thinking about your emotions during a negative memory, looking away from the worst emotions and thinking about the context, like a friend who was there, what the weather was like, or anything else non-emotional that was part of the memory, will rather effortlessly take your mind away from the unwanted emotions associated with that memory. Once you immerse yourself in other details, your mind will wander to something else entirely, and you won’t be focused on the negative emotions as much.”
This simple strategy, the study suggests, is a promising alternative to other emotion-regulation strategies, like suppression or reappraisal.
“Suppression is bottling up your emotions, trying to put them away in a box. This is a strategy that can be effective in the short term, but in the long run, it increases anxiety and depression,” explains Sanda Dolcos, co-author on the study and postdoctoral research associate at the Beckman Institute and in the Department of Psychology.
“Another otherwise effective emotion regulation strategy, reappraisal, or looking at the situation differently to see the glass half full, can be cognitively demanding. The strategy of focusing on non-emotional contextual details of a memory, on the other hand, is as simple as shifting the focus in the mental movie of your memories and then letting your mind wander.”
Not only does this strategy allow for effective short-term emotion regulation, but it has the possibility of lessening the severity of a negative memory with prolonged use.
In the study, participants were asked to share their most emotional negative and positive memories, such as the birth of a child, winning an award, or failing an exam, explained Sanda Dolcos. Several weeks later participants were given cues that would trigger their memories while their brains were being scanned using magnetic resonance imaging (MRI). Before each memory cue, the participants were asked to remember each event by focusing on either the emotion surrounding the event or the context. For example, if the cue triggered a memory of a close friend’s funeral, thinking about the emotional context could consist of remembering your grief during the event. If you were asked to remember contextual elements, you might instead remember what outfit you wore or what you ate that day.
“Neurologically, we wanted to know what happened in the brain when people were using this simple emotion-regulation strategy to deal with negative memories or enhance the impact of positive memories,” explained Ekaterina Denkova, first author of the report. “One thing we found is that when participants were focused on the context of the event, brain regions involved in basic emotion processing were working together with emotion control regions in order to, in the end, reduce the emotional impact of these memories.”
Using this strategy promotes healthy functioning not only by reducing the negative impact of remembering unwanted memories, but also by increasing the positive impact of cherished memories, Florin Dolcos said.
In the future, the researchers hope to determine if this strategy is effective in lessening the severity of negative memories over the long term. They also hope to work with clinically depressed or anxious participants to see if this strategy is effective in alleviating these psychiatric conditions.
These results were published in Social Cognitive and Affective Neuroscience.
A joint study by researchers at the University of California, San Diego and the University of Toronto has found that a computer system spots real or faked expressions of pain more accurately than people can.
The work, titled “Automatic Decoding of Deceptive Pain Expressions,” is published in the latest issue of Current Biology.
“The computer system managed to detect distinctive dynamic features of facial expressions that people missed,” said Marian Bartlett, research professor at UC San Diego’s Institute for Neural Computation and lead author of the study. “Human observers just aren’t very good at telling real from faked expressions of pain.”
Senior author Kang Lee, professor at the Dr. Eric Jackman Institute of Child Study at the University of Toronto, said “humans can simulate facial expressions and fake emotions well enough to deceive most observers. The computer’s pattern-recognition abilities prove better at telling whether pain is real or faked.”
The research team found that humans could not discriminate real from faked expressions of pain better than random chance – and, even after training, only improved accuracy to a modest 55 percent. The computer system attains an 85 percent accuracy.
“In highly social species such as humans,” said Lee, “faces have evolved to convey rich information, including expressions of emotion and pain. And, because of the way our brains are built, people can simulate emotions they’re not actually experiencing – so successfully that they fool other people. The computer is much better at spotting the subtle differences between involuntary and voluntary facial movements.”
“By revealing the dynamics of facial action through machine vision systems,” said Bartlett, “our approach has the potential to elucidate ‘behavioral fingerprints’ of the neural-control systems involved in emotional signaling.”
The single most predictive feature of falsified expressions, the study shows, is the mouth, and how and when it opens. Fakers’ mouths open with less variation and too regularly.
“Further investigations,” said the researchers, “will explore whether over-regularity is a general feature of fake expressions.”
In addition to detecting pain malingering, the computer-vision system might be used to detect other real-world deceptive actions in the realms of homeland security, psychopathology, job screening, medicine, and law, said Bartlett.
“As with causes of pain, these scenarios also generate strong emotions, along with attempts to minimize, mask, and fake such emotions, which may involve ‘dual control’ of the face,” she said. “In addition, our computer-vision system can be applied to detect states in which the human face may provide important clues as to health, physiology, emotion, or thought, such as drivers’ expressions of sleepiness, students’ expressions of attention and comprehension of lectures, or responses to treatment of affective disorders.”
Finnish and Danish researchers have developed a new method that performs decoding, or brain-reading, during continuous listening to real music. Based on recorded brain responses, the method predicts how certain features related to tone color and rhythm of the music change over time, and recognizes which piece of music is being listened to. The method also allows pinpointing the areas in the brain that are most crucial for the processing of music. The study was published in the journal NeuroImage.
Using functional magnetic resonance imaging (fMRI), the research team at the Finnish Centre of Excellence in Interdisciplinary Music Research in the Universities of Jyväskylä and Helsinki, and the Center for Functionally Integrative Neuroscience in Aarhus University, Denmark, recorded the brain responses of participants while they were listening to a 16-minute excerpt of the album Abbey Road by the Beatles. Following this, they used computational algorithms to extract a collection of musical features from the musical recording. Subsequently, they employed a collection of machine-learning methods to train a computer model that predicts how the features of the music change over time. Finally, they develop a classifier that predicts which part of the music the participant was listening to at each time.
The researchers found that most of the musical features included in the study could be reliably predicted from the brain data. They also found that the piece being listened to could be predicted significantly better than chance. Fairly large differences were however found between participants in terms of the prediction accuracy. An interesting finding was that areas outside of the auditory cortex, including motor, limbic, and frontal areas, had to be included in the models to obtain reliable predictions, providing thus evidence for the important role of these areas in the processing of musical features.
"We believe that decoding provides a method that complements other existing methods to obtain more reliable information about the complex processing of music in the brain", says Professor Petri Toiviainen from the University of Jyväskylä. "Our results provide additional evidence for the important involvement of emotional and motor areas in music processing."