TL;DR
- An EPFL scientist has pinpointed the signs of brain activity that make up our brain fingerprint, which — like our regular fingerprint — is unique. “I think about it every day and dream about it at night. It’s been my whole life for five years now,” says Enrico Amico, a scientist and SNSF Ambizione Fellow at EPFL’s Medical Image Processing Laboratory and the EPFL Center for Neuroprosthetics. He’s talking about his research on the human brain in general, and on brain fingerprints in particular. He learned that every one of us has a brain “fingerprint” and that this fingerprint constantly changes in time. His findings have just been published in Science Advances.
- Scientists argue that efforts to understand human cognition should expand beyond the study of individual brains. They call on neuroscientists to incorporate evidence from social science disciplines to better understand how people think.
- Meaningful social interactions are critical to an individual’s well-being, and such interactions rely on people’s behaviors towards one another. In research published in Science, investigators at Massachusetts General Hospital (MGH) have mapped the neurons in the brain that allow a monkey to process and remember the interactions and behaviors of another monkey to influence the animal’s own actions. The findings might be used to develop treatment strategies for people with neuropsychiatric conditions.
- Neuroscientists used wireless devices to record the neural activity of freely interacting Egyptian fruit bats, providing researchers with the first glimpse into how the brains of social mammals process complex group interactions.
- Newly published research details how a team of scientists from the University Miguel Hernández (Spain), the Netherlands Institute of Neuroscience (Netherlands) and the John A. Moran Eye Center at the University of Utah (USA) successfully created a form of artificial vision for a blind woman using a brain implant.
- Processing of sensory impressions and information depends very much on how the synapses in our brain work. A team has now shown how lipid and protein regulation impact brain’s processing of a beautiful and stimulating environment. The lipids located in the membranes of the synapses are central to signal transmission, the researchers report.
- A new study has uncovered neuronal circuitry in the brain of rodents that may play an important role in mediating pain-induced anhedonia — a decrease in motivation to perform reward-driven behaviors. Researchers were able to change the activity of this circuit and restore levels of motivation in a pre-clinical model of pain tested in rodents.
- It remains a central challenge in psychiatry to reliably judge whether a patient will respond to treatment. Researchers now show that moment-to-moment fluctuations in brain activity can reliably predict whether patients with social anxiety disorder will be receptive to cognitive behavioral therapy (CBT).
- A new study used functional magnetic resonance imaging to examine the brain activity of 51 male-female romantic couples as they experienced intimate partner aggression in real time. They found that aggression toward intimate partners was associated with aberrant activity in the brain’s medial prefrontal cortex, or MPFC, which has many functions, but among them is the ability to foster perceptions of closeness with and value of other people.
- Very young children learn words at a tremendous rate. Now researchers have seen how specific brain regions activate as two-year-olds remember newly learned words — while the children were sleeping.
- And more!
Neuroscience market
The global neuroscience market size was valued at USD 28.4 billion in 2016 and it is expected to reach USD 38.9 billion by 2027.
Latest news and researches
When makes you unique: Temporality of the human brain fingerprint
by Dimitri Van De Ville, Younes Farouj, Maria Giulia Preti, Raphaël Liégeois, Enrico Amico in Science Advances
“I think about it every day and dream about it at night. It’s been my whole life for five years now,” says Enrico Amico, a scientist and SNSF Ambizione Fellow at EPFL’s Medical Image Processing Laboratory and the EPFL Center for Neuroprosthetics. He’s talking about his research on the human brain in general, and on brain fingerprints in particular. He learned that every one of us has a brain “fingerprint” and that this fingerprint constantly changes in time. His findings have just been published in Science Advances.
“My research examines networks and connections within the brain, and especially the links between the different areas, in order to gain greater insight into how things work,” says Amico.
“We do this largely using MRI scans, which measure brain activity over a given time period.” His research group processes the scans to generate graphs, represented as colorful matrices, that summarize a subject’s brain activity. This type of modeling technique is known in scientific circles as network neuroscience or brain connectomics. “All the information we need is in these graphs, that are commonly known as “functional brain connectomes.” The connectome is a map of the neural network. They inform us about what subjects were doing during their MRI scan — if they were resting or performing some other tasks, for example. Our connectomes change based on what activity was being carried out and what parts of the brain were being used,” says Amico.
A few years ago, neuroscientists at Yale University studying these connectomes found that every one of us has a unique brain fingerprint. Comparing the graphs generated from MRI scans of the same subjects taken a few days apart, they were able to correctly match up the two scans of a given subject nearly 95% of the time. In other words, they could accurately identify an individual based on their brain fingerprint.
“That’s really impressive because the identification was made using only functional connectomes, which are essentially sets of correlation scores,” says Amico.
He decided to take this finding one step further. In previous studies, brain fingerprints were identified using MRI scans that lasted several minutes. But he wondered whether these prints could be identified after just a few seconds, or if there was a specific point in time when they appear — and if so, how long would that moment last?
“Until now, neuroscientists have identified brain fingerprints using two MRI scans taken over a fairly long period. But do the fingerprints actually appear after just five seconds, for example, or do they need longer? And what if fingerprints of different brain areas appeared at different moments in time? Nobody knew the answer. So, we tested different time scales to see what would happen,” says Amico.
His research group found that seven seconds wasn’t long enough to detect useful data, but that around 1 minute and 40 seconds was.
“We realized that the information needed for a brain fingerprint to unfold could be obtained over very short time periods,” says Amico. “There’s no need for an MRI that measures brain activity for five minutes, for example. Shorter time scales could work too.”
His study also showed that the fastest brain fingerprints start to appear from the sensory areas of the brain, and particularly the areas related to eye movement, visual perception and visual attention. As time goes by, also frontal cortex regions, the ones associated to more complex cognitive functions, start to reveal unique information to each of us.
The next step will be to compare the brain fingerprints of healthy patients with those suffering from Alzheimer’s disease.
“Based on my initial findings, it seems that the features that make a brain fingerprint unique steadily disappear as the disease progresses,” says Amico. “It gets harder to identify people based on their connectomes. It’s as if a person with Alzheimer’s loses his or her brain identity.”
Along this line, potential applications might include early detection of neurological conditions where brain fingerprints get disappear. Amico’s technique can be used in patients affected by autism, or stroke, or even in subjects with drug addictions.
“This is just another little step towards understanding what makes our brains unique: the opportunities that this insight might create are limitless.”
Enrico Amico’s research has been made possible thanks to an SNSF Ambizione Fellowship.
“This unique program was able to attract a promising young researcher to Switzerland when he was a post-doctoral scholar at Purdue University,” mentions Prof. Van De Ville, head of the Medical Image Processing Laboratory. “Ambizione has allowed him to pursue independently his research ideas, but also to choose on successful collaborations with the host lab. It is rewarding to see these goals achieved.”
Cognitive Neuroscience Meets the Community of Knowledge
by Steven A. Sloman, Richard Patterson, Aron K. Barbey in Frontiers in Systems Neuroscience
In a new paper, scientists suggest that efforts to understand human cognition should expand beyond the study of individual brains. They call on neuroscientists to incorporate evidence from social science disciplines to better understand how people think.
“Accumulating evidence indicates that memory, reasoning, decision-making and other higher-level functions take place across people,” the researchers wrote in a review in the journal Frontiers in Systems Neuroscience. “Cognition extends into the physical world and the brains of others.”
The co-authors — neuroscientist Aron Barbey, a professor of psychology at the University of Illinois Urbana-Champaign; Richard Patterson, a professor emeritus of philosophy at Emory University; and Steven Sloman, a professor of cognitive, linguistic and psychological sciences at Brown University — wanted to address the limitations of studying brains in isolation, out of the context in which they operate and stripped of the resources they rely on for optimal function.
“In cognitive neuroscience, the standard approach is essentially to assume that knowledge is represented in the individual brain and transferred between individuals,” Barbey said. “But there are, we think, important cases where those assumptions begin to break down.”
Take, for instance, the fact that people often “outsource” the task of understanding or coming to conclusions about complex subject matter, using other people’s expertise to guide their own decision-making.
“Most people will agree that smoking contributes to the incidence of lung cancer — without necessarily understanding precisely how that occurs,” Barbey said. “And when doctors diagnose and treat disease, they don’t transfer all of their knowledge to their patients. Instead, patients rely on doctors to help them decide the best course of action. “Without relying on experts in our community, our beliefs would become untethered from the social conventions and scientific evidence that are necessary to support them,” he said. “It would become unclear, for example, whether ‘smoking causes lung cancer,’ bringing into question the truth of our beliefs, the motivation for our actions.”
To understand the role that knowledge serves in human intelligence, the researchers wrote that it is necessary to look beyond the individual and to study the community.
“Cognition is, to a large extent, a group activity, not an individual one,” Sloman said. “People depend on others for their reasoning, judgment and decision-making. Cognitive neuroscience is not able to shed light on this aspect of cognitive processing.”
The limitations of individual knowledge and human dependence on others for understanding are the themes of “The Knowledge Illusion: Why We Never Think Alone,” a book Sloman wrote with Phil Fernbach, a cognitive scientist and professor of marketing at the University of Colorado.
“The challenge for cognitive neuroscience becomes how to capture knowledge that does not reside in the individual brain but is outsourced to the community,” Barbey said.
Neuroscientific methods such as functional MRI were designed to track activity in one brain at a time and have limited capacity for capturing the dynamics that occur when individuals interact in large communities, he said.
Some neuroscientists are trying to overcome this limitation. In a recent study, researchers placed two people face-to-face in a scanner and tracked their brain activity and eye movements while they interacted. Other teams use a technique called “hyperscanning,” which allows the simultaneous recording of brain activity in people who are physically distant from each another but interacting online.
Such efforts have found evidence suggesting that the same brain regions are activated in people who are effectively communicating with one another or cooperating on a task, Barbey said. These studies are also showing how brains operate differently from one another, depending on the type of interaction and the context.
Several fields of research are ahead of neuroscience in understanding and embracing the collective, collaborative nature of knowledge, Patterson said. For example, “social epistemology” recognizes that knowledge is a social phenomenon that depends on community norms, a shared language and a reliable method for testing the trustworthiness of potential sources.
“Philosophers studying natural language also illustrate how knowledge relies on the community,” Patterson said. “For example, according to ‘externalism,’ the meaning of words depends on how they are used and represented within a social context. Thus, the meaning of the word and its correct use depends on collective knowledge that extends beyond the individual.”
To address these shortfalls, neuroscientists can look to other social science fields, Barbey said.
“We need to incorporate not only neuroscience evidence, but also evidence from social psychology, social anthropology and other disciplines that are better positioned to study the community of knowledge,” he said.
Visual percepts evoked with an Intracortical 96-channel microelectrode array inserted in human occipital cortex
by Eduardo Fernández, Arantxa Alfaro, Cristina Soto-Sánchez, Pablo González-López, Antonio M. Lozano Ortega, Sebastian Peña, María Dolores Grima, Alfonso Rodil, Bernardeta Gómez, Xing Chen, Pieter R. Roelfsema, John D. Rolston, Tyler S. Davis, Richard A. Normann in Journal of Clinical Investigation
Newly published research details how a team of scientists from the University Miguel Hernández (Spain), the Netherlands Institute of Neuroscience (Netherlands) and the John A. Moran Eye Center at the University of Utah (USA) successfully created a form of artificial vision for a blind woman using a brain implant.
In the article Eduardo Fernández, MD, PhD, from the University Miguel Hernández details how an array of penetrating electrodes produced a simple form of vision for a 58-year-old blind volunteer. The team conducted a series of experiments with the blind volunteer in their laboratory in Elche, Spain. The results represent a leap forward for scientists hoping to create a visual brain prosthesis to increase independence of the blind.
A neurosurgeon implanted a microelectrode array composed of 100 microneedles into the visual cortex of the blind woman to both record from and stimulate neurons located close to the electrodes. She wore eyeglasses equipped with a miniature video camera; specialized software encoded the visual data collected by the camera and sent it to electrodes located in the brain. The array then stimulated the surrounding neurons to produce white points of light known as ‘phosphenes’ to create an image.
The blind woman was a former science teacher and had been completely blind for 16 years at the time of the study. She had no complications from the surgery, and researchers determined that the implant did not impair or negatively affect brain function. With the help of the implant, she was able to identify lines, shapes and simple letters evoked by different patterns of stimulation. To assist her in practicing with the prosthesis, researchers created a video game with a character from the popular television show The Simpsons. Due to her extensive involvement and insight, she is also co-author on the article.
“These results are very exciting because they demonstrate both safety and efficacy and could help to achieve a long-held dream of many scientists, which is the transfer information from the outside world directly to the visual cortex of blind individuals, thereby restoring a rudimentary form of sight,” said Prof. Eduardo Fernández. He also added that “although these preliminary results are very encouraging, we should be aware that there are still a number of important unanswered questions and that many problems have to be solved before a cortical visual prosthesis can be considered a viable clinical therapy.”
“This new study provides proof-of-principle and demonstrate that our previous findings in monkey experiments can be translated to humans,” said Prof. P. Roelfsema, a co-author on the study. “This work is likely to become a milestone for the development of new technologies that could transform the treatment of blindness.”
“One goal of this research is to give a blind person more mobility,” said Prof. R. A. Normann, also a co-author on the study. “It could allow them to identify a person, doorways, or cars. It could increase independence and safety. That’s what we’re working toward.”
The research team hopes that the next set of experiments will use a more sophisticated image encoder system, capable of stimulating more electrodes simultaneously and to elicit more complex visual images.
Social agent identity cells in the prefrontal cortex of interacting groups of primates
by Raymundo Báez-Mendoza, Emma P. Mastrobattista, Amy J. Wangand, Ziv M. Williams in Science
Meaningful social interactions are critical to an individual’s well-being, and such interactions rely on people’s behaviors towards one another. In research published in Science, investigators at Massachusetts General Hospital (MGH) have mapped the neurons in the brain that allow a monkey to process and remember the interactions and behaviors of another monkey to influence the animal’s own actions. The findings might be used to develop treatment strategies for people with neuropsychiatric conditions.
The study had three Rhesus monkeys sit around a rotary table and take turns to offer an apple slice to one of the other two monkeys. At the same time, the researchers recorded the activity of individual neurons in a brain area known to play a role in social cognition, called the dorsomedial prefrontal cortex (dmPFC).
During these interactions, the monkeys reciprocated past offers of an apple slice and retaliated when they did not receive a slice from another. The researchers’ recordings identified distinct neurons in the dmPFC that responded to the actions of other monkeys in the group. Certain neurons were activated with a particular action and outcome of specific individuals within the group (such as a neighbor monkey offering an apple slice leads to the outcome of receiving the reward). Many of the neurons encoded information not only about the actions and outcomes of specific individuals but also about their past behavior. This information about past interactions with group members influenced an animal’s upcoming decisions to reciprocate or retaliate, and investigators could use the neuronal information to predict which monkey would receive an apple slice from a particular monkey even before it was offered.
“This finding suggested that the dmPFC plays a role in strategic decisions. To test this idea, we disrupted the normal activity in this area and found that the animals were less likely to reciprocate,” says lead author Raymundo Báez-Mendoza, PhD, an investigator in the Department of Neurosurgery at MGH.
The results suggest that the dmPFC plays an important role in mapping out our actions and outcomes as well as the actions of others.
“In neuropsychiatric conditions in which this ability is compromised, treatments aimed at improving the functioning of this brain area, either directly or indirectly, might improve peoples’ lives,” says senior author Ziv Williams, MD.
Cortical representation of group social communication in bats
by Maimon C. Rose, Boaz Styr, Tobias A. Schmid, Julie E. Elie and Michael M. Yartsev in Science
Whether chatting with friends at a dinner party or managing a high-stakes meeting at work, communicating with others in a group requires a complex set of mental tasks. Our brains must track who is speaking and what is being said, as well as what our relationship to that person may be — because, after all, we probably give the opinion of our best friend more weight than that of a complete stranger.
A study provides the first glimpse into how the brains of social mammals process these types of complex group interactions.
In the study, neuroscientists at the University of California, Berkeley, used wireless neural recording devices to track the brain activity of Egyptian fruit bats as they freely interacted in groups and occasionally vocalized to each other through high-pitched screeches and grunts.
“Most studies of communication, particularly vocalization, are typically performed with single animals or with pairs of animals, but basically none have been conducted in actual group settings,” said study co-first author Maimon Rose, a graduate student in the NeuroBat Lab at UC Berkeley. “However, many social mammals, including humans, typically interact in groups. Egyptian fruit bats, specifically, like to interact within large colonies.”
By tracking which of the bats vocalized, while simultaneously measuring the real-time neural activity in both the vocalizing and the listening bats, the researchers were able to decode how neurons in the bats’ frontal cortices distinguished among vocalizations made by themselves and by others, as well how the bats distinguished among different individuals in the group.
When they compared the neural recordings among the different bats, they also found that brain activity became highly correlated when a bat made a vocalization. Surprisingly, they found that communication produced by bats that were “friendlier” — those that spent more time in close proximity to others — induced a higher degree of correlations across the brains of the group members.
“Other neuroscience studies have tried to examine small pieces of these interactions individually. For example, one study might examine how neurons respond when somebody else speaks, and then a separate study might look at how neurons respond when that individual speaks,” said study senior author Michael Yartsev,an assistant professor of neurobiology and bioengineering at UC Berkeley. “This study is the first to really put all of these pieces together to get a full picture of communication within a social group.”
Like humans, Egyptian fruit bats are highly social creatures. After long nights spent flying 10 miles or more in search of ripe fruit, these nocturnal animals pass the daylight hours packed into tight caves and crevices alongside hundreds or thousands of other bats. Not surprisingly, studies suggest that these bats typically vocalize to squabble over food, sleeping space and mating attempts.
“These bats are very long-lived — they live about 25 years — and basically their entire lives are spent in this group social living,” Yartsev said. “So, the ability to live together in a group and communicate with each other is an inherent feature of their lives.”
Even in laboratory settings, bats seem to prefer the comfort of a crowd, typically spending most of their time physically pressed against each other in a tight cluster. Notably, aside from making clicking noises for echolocation, Egyptian fruit bats do not engage in any long-distance form of communication and appear to vocalize to other bats only when clustered together.
“If you visit these bat caves, you can just look up and see tens of thousands of animals,” Yartsev said. “So, it really wouldn’t make sense for a bat to shout across to the cave to another bat.”
Bats’ habit of only vocalizing within tight social clumps makes them ideal subjects for studying group communication because, if a bat does call out while in a cluster, that call is most likely an indicator that social communication is taking place. However, this behavior also posed one of many technical challenges for the research team, said study co-first author Boaz Styr, a postdoctoral researcher in the NeuroBat Lab.
“One big problem was trying to identify which bat made a vocalization, because they spend their time in tight clusters and sometimes obscure each other,” Styr said. “Even though we had high resolution cameras recording at different angles, and lots of microphones around, it could be hard to pinpoint which bat was making a call at exactly which point.”
During the experiments, four to eight bats were allowed to freely interact in a darkened enclosure in the lab, and allowed to spontaneously vocalize. To accurately identify which bat made each vocalization, the team developed wireless vibration sensors that the bats could wear around their necks, almost like necklaces, and which could detect the vibrations created when a bat made a call.
“These vibration sensors, paired with our ability to wirelessly record neural data from multiple bats at the same time, allowed us to create this experiment in which the bats could freely behave and spontaneously communicate,” Styr said. “Getting all of these technical things to work together was extremely challenging, but it allowed us to ask these very important questions.”
In one set of experiments, the researchers allowed groups of four or five bats to freely interact within a darkened enclosure in the lab, while carefully monitoring each bat’s vocalizations and brain activity.
They found that, within each bat’s frontal cortex — an area known to be involved in mediating social behaviors in animals and humans — separate sets of neurons were activated, depending on which bat in the group vocalized; in other words, a vocalization from one bat would stimulate activity in one set of neurons, while a vocalization from a different bat would stimulate a different set of neurons. These correlations were so strong that, after identifying which sets of neurons corresponded to which bat, the researchers could identify which bat had vocalized purely by looking at the neural activity of the other bats.
“What these individual neurons cared about was, ‘Am I making the call? Or is somebody else making the call?’ no matter what type of vocalization it was,” Styr said. “Other neurons were only sensitive to when one specific bat within the group was talking.”
Earlier work from the NeuroBat Lab has demonstrated that the brains of bat pairs tend to sync up when they socialize. In this study, the authors discovered that during vocal communication, the whole group syncs up together. This effect was not observed when the bats simply heard playback of the same sounds, suggesting that this phenomenon was specific to active communication taking place among the group members.
Intriguingly, the degree of correlation among the group members’ brains appeared to depend on which bat was talking, with some bats having stronger synchronization with specific individuals. Remarkably, these inter-brain patterns lasted for weeks, presumably representing stable social relationships among the individuals.
To better understand how social dynamics impact brain activity, the researchers conducted a separate set of experiments in which eight bats were allowed to freely interact in a larger enclosure. In addition to monitoring the vocalizations and neural activity of each bat, they also tracked each bat’s spatial position relative to the other bats in the group.
“Bats can recognize and have stable social relationships with other individual bats, even over long periods of time and in different circumstances,” Rose said. “And because we had this group of bats, we decided to track their positions in a larger area to see if that would tell us anything about their social relationships — who likes whom, and who are more sociable bats and the less sociable bats.”
They found that, while most “in-cluster” bats spent nearly all their time clumped together with other bats, a couple of “out-of-cluster” bats spent more time off to the side, separate from the group. Surprisingly, the team also found that the in-cluster or out-of-cluster status of a bat impacted the neural activity of the other bats during vocalizations.
“We found that when the in-cluster bats vocalized, they elicited a much more accurate neural representation of their identity in the other bats and also elicited a much higher level of brain synchrony within the group,” Rose said. “So, while its not entirely clear what exactly is going on, it seems that the behavior of the out-of-cluster bats really shifts their neural representation in the brains of the other bats.”
Understanding the neural underpinnings of why some individuals can navigate almost any social situation with ease, while others are consistently ostracized or misunderstood, could have major implications for improving human mental health, Yartsev said. He hopes the study inspires neuroscientists to take a more comprehensive look at group communication within other social mammals.
Multiomics of synaptic junctions reveals altered lipid metabolism and signaling following environmental enrichment
by Maximilian Borgmeyer, Cristina Coman, Canan Has, Hans-Frieder Schött, Tingting Li, Philipp Westhoff, Yam F.H. Cheung, Nils Hoffmann, PingAn Yuanxiang, Thomas Behnisch, Guilherme M. Gomes, Mael Dumenieu, Michaela Schweizer, Michaela Chocholoušková, Michal Holčapek, Marina Mikhaylova, Michael R. Kreutz, Robert Ahrends in Cell Reports
Processing of sensory impressions and information depends very much on how the synapses in our brain work. A team has now shown how lipid and protein regulation impact brain’s processing of a beautiful and stimulating environment. The lipids located in the membranes of the synapses are central to signal transmission, the researchers report.
“We usually enjoy a beautiful environment, socializing, a cosy apartment, good restaurants, a park — all this inspires us,” says Robert Ahrends from the Institute of Analytical Chemistry of the University of Vienna and former group leader at ISAS in Dortmund. Previous studies have already shown that such an enriched environment can sometimes have a positive effect on child development or even on the human ability to regenerate, e.g. after a stroke, however the reason for these observations “was not yet clarified at the molecular level.”
Stimulating sensory perceptions are ultimately formed via the activity or regulation of synapses, i.e. those connecting units between our neurons that transfer information from one nerve cell to another. To clarify the underlying molecular principles, the researchers offered the rodents, their model organisms, an enriched environment based on plenty of room to move, a running wheel and other toys. With the help of post-genomic analysis strategies (multiomics) and using state-of-the-art mass spectrometry and microscopy as well as bioinformatics for data analysis, they investigated the regulation of synapses in the hippocampus of the rodents, more precisely the interaction of the proteins and especially lipids (fats) located in the synaptic membranes.
“80 percent of the brain cells are only supporting cells. We have therefore focused on the synapses as central sites of signal transmission and isolated them,” says neuroscientist Michael Kreutz.
The team gathered quantitative and qualitative information about the network of molecules regulated at synapses and examined their lipid metabolism, also under the influence of an enriched environment. The analyses revealed that 178 proteins and 20 lipids were significantly regulated depending on whether the rodents had spent time in an enriched environment or an uncomfortable one.
The regulations were characterized by specific lipids as well as proteins of the organisms’ endocannabinoid metabolism, which was particularly strongly influenced by the sensory impressions of an enriched environment.
If the information arrives at the synapse as a signal, signal processing is enhanced, which ultimately leads to improved learning and development. In this context, the complex networks of lipids and proteins had a decisive effect on the functioning of the synapses. Thus, the current study provides a molecular explanation for why an enhancing stimulating environment can have a positive effect on neuronal plasticity and brain development.
Moment-to-moment brain signal variability reliably predicts psychiatric treatment outcome
by Kristoffer N.T. Månsson, Leonhard Waschke, Amirhossain Manzouri, Tomas Furmark, Håkan Fischer, Douglas D. Garrett in Biological Psychiatry
It remains a central challenge in psychiatry to reliably judge whether a patient will respond to treatment. In a new study published in the journal Biological Psychiatry, researchers from Karolinska Institutet in Sweden and the Max Planck Institute for Human Development in Germany show that moment-to-moment fluctuations in brain activity can reliably predict whether patients with social anxiety disorder will be receptive to cognitive behavioural therapy (CBT).
Viable predictors of psychiatric treatment response are often sought, but remain elusive. Brain imaging techniques such as functional magnetic resonance imaging (fMRI) have shown promise, but low reliability has limited the utility of typical fMRI measures as harbingers of treatment success. Although historically considered a marker of ‘noise’ in the brain, moment-to-moment brain signal variability continues to gain momentum as a sensitive and reliable indicator of individual differences in the effectiveness of neural function. However, neural variability had not yet been examined in relation to psychiatric treatment outcomes.
To do so, the research team designed a unique study; 45 patients with social anxiety disorder had their brains imaged during passive rest and emotional face viewing (a social anxiety-relevant task) in two sessions (11 weeks apart) to capture moment-to-moment neural variability. Then, patients underwent a 9-week cognitive behavioural therapy delivered via the internet. The researchers showed that brain signal variability measured during the emotional task was the strongest and most reliable predictor of treatment outcome, despite the task only taking three minutes for patients to complete.
“Variability in brain signals is often considered measurement ‘noise,’ something to be eliminated prior to further analysis. We show first evidence that neural variability may be a reliable and efficient predictor of psychiatric treatment outcome, particularly when disorder-relevant task designs are utilized. We simply need to rethink our standard approaches in psychiatric neuroimaging to maximize clinical impact,” says lead author Dr. Kristoffer Månsson, clinical psychologist and researcher at the Department of Clinical Neuroscience, Karolinska Institutet.
In the next phase of their research, the authors will collect larger samples to examine whether brain signal variability can predict which specific treatment a patient should undergo.
“If moment-to-moment neural variability is to be worth its salt as a clinically useful predictor of treatment outcome, it needs to tell clinicians not only how much a patient will respond to a given treatment, but whether treatment A or B is better suited for them. Establishing this will be our long-term goal. In the meantime, our methods are immediately and openly available to any researcher interested in whether neural variability provides clinical utility within and beyond social anxiety disorder patients,” says senior author Dr. Douglas Garrett, leader of the Lifespan Neural Dynamics Group at the Max Planck UCL Centre for Computational Psychiatry and Ageing Research in Berlin.
Neural mechanisms of intimate partner aggression
by David S. Chester, Alexandra M. Martelli, Samuel J. West, Emily N. Lasko, Phoebe Brosnan, Anastasia Makhanova, Andrea L. Meltzer, James K. McNulty in Biological Psychology
Why do people hurt the ones they claim to love? That question has driven researchers to discover much about the psychological and sociological predictors and consequences of intimate partner aggression. But an understanding of the neurobiological causes — or what happens in the brain — remains incomplete.
A new study led by Virginia Commonwealth University researchers used functional magnetic resonance imaging to examine the brain activity of 51 male-female romantic couples as they experienced intimate partner aggression in real time.
They found that aggression toward intimate partners was associated with aberrant activity in the brain’s medial prefrontal cortex, or MPFC, which has many functions, but among them is the ability to foster perceptions of closeness with and value of other people.
“We found that aggression towards intimate partners has a unique signature in the brain,” said lead author David Chester, Ph.D., an associate professor in the Department of Psychology in the College of Humanities and Sciences. “There is something distinct happening at the neural level when people decide whether to harm their romantic partners, a process that differs in a meaningful way from decisions about whether to harm friends or strangers.”
The research was led by Chester’s Social Psychology and Neuroscience Lab, which seeks to understand the psychological and biological processes that motivate and constrain aggressive behavior. The study, “Neural Mechanisms of Intimate Partner Aggression,” will be published in the journal Biological Psychology.
The researchers were able to observe couples’ brain activity during intimate partner aggression by asking participants to play a computer game against three people, one at a time: their romantic partner, a close friend and a stranger. In reality, they were playing against a computer.
The participants were tasked with pressing a button faster than their opponents. The loser, they were told, would be punished with a nasty blast of sound in their headphones. The researchers measured aggression by giving participants, and their fictitious opponents, the opportunity to select the volume of that sound blast, with higher volume representing more aggression, and lower volume representing less aggression.
“Basically, we gave participants repeated opportunities to hurt or not hurt each of these three people, and we examined how brain activity changed based on who they thought they were hurting,” Chester said. “But … no one was actually hurt by this computer game, participants unknowingly played against the computer.”
The researchers’ findings also extended beyond the lab into the real world. They had participants fill out a validated questionnaire that asked whether they had perpetrated acts of intimate partner violence prior to the study.
They found that blunted medial prefrontal cortex activity predicted some of the participants’ real-world acts of intimate partner violence.
“We expected to see that intimate partner aggression was linked to a unique signature of brain activity,” Chester said. “What we were surprised about was the ability of this brain signature to predict real-world intimate partner violence.”
They also investigated how men’s and women’s neural activity affected each other’s aggression. They found that women’s intimate partner aggression was predicted by their male partner’s brain response to perceived provocation.
“This result fits with the well-established finding that women’s intimate partner aggression may very often be in self-defense,” Chester said.
Taken together, he said, the study’s results provide new insights into brain regions that are likely to be fruitful targets for interventions that aim to reduce intimate partner aggression and help science build an accurate brain model of such harmful acts.
Chester added that the researchers approached this study with utmost care. Couples were pre-screened to ensure they were not at elevated risk for intimate partner violence. The researchers carefully debriefed each participant individually to make sure they felt comfortable to be reunited with their partner. And they carefully debriefed both partners again as a couple to make sure there were no lingering, negative effects of the study.
“We had robust protocols in place in case anything went wrong, to safeguard the well-being of our participants,” Chester said. “It is of paramount importance that studies into intimate partner aggression prioritize the safety and well-being of their participants, and we believe we achieved this goal.”
While this study focused on male-female intimate partner aggression, Chester said future work is needed to examine these dynamics across a greater diversity of gender identities and sexual orientations.
Pain induces adaptations in ventral tegmental area dopamine neurons to drive anhedonia-like behavior
by T Markovic, et al. in Nature Neuroscience
A new study published today in Nature Neuroscience has uncovered neuronal circuitry in the brain of rodents that may play an important role in mediating pain-induced anhedonia — a decrease in motivation to perform reward-driven behaviors. In the study funded by the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health, researchers were able to change the activity of this circuit and restore levels of motivation in a pre-clinical model of pain tested in rodents.
On a basic level, pain includes two components — sensory (the pain you feel) and affective (the negative emotional component of pain). The presence of anhedonia, a hallmark of affective pain, is a common feature of depression, and may also increase one’s vulnerability to opioid use disorder (OUD). Given this relationship, better understanding the brain circuitry involved in the affective component of pain is an important part of NIDA’s research portfolio.
“Chronic pain is experienced on many levels beyond just the physical, and this research demonstrates the biological basis of affective pain. It is a powerful reminder that psychological phenomena such as affective pain are the result of biological processes,” said NIDA Director, Nora D. Volkow, M.D. “It is exciting to see the beginnings of a path forward that may pave the way for treatment interventions that address the motivational and emotional effects of pain.”
To investigate what might be underlying the affective component of pain, researchers at Washington University in St. Louis built upon prior studies where researchers observed that rats in pain were more likely to consume higher doses of heroin than the rats that were not in pain. In addition, their motivation for natural rewards, such as sugar tablets, was decreased. The new line of investigation sought to uncover the brain circuitry involved in this pathway, to better understand the relationship between pain and related changes in one’s motivational state.
In this new study, the researchers measured the activity of dopamine neurons in the ventral tegmental area, part of the brain’s “reward system,” which process rewards and orchestrate motivated behavior. Dopamine neuronal activity was measured in rats while they pressed a lever with their front paw to receive a sugar tablet (the reward). To assess the impact of pain on the animals’ behavior and activity of these dopamine neurons, either saline (the control condition) or a solution that produces a local inflammation (the pain condition) was injected into the hind paw.
After 48 hours, the researchers found that rats in the pain condition pressed the lever less to obtain the sugar tablet, demonstrating a decrease in motivation, and that their dopamine neurons were less active. They then discovered that the reason the dopamine neurons were less active was because pain was activating cells from a region of the brain known as the rostromedial tegmental nucleus (RMTg), which makes the inhibitory neurochemical GABA, and GABA blocks the activity of the dopamine neurons.
However, when the researchers artificially restored the activity of dopamine neurons (through a process called chemogenetics), they were able to reverse the negative effect of pain on the reward system and reinstate the motivation to push the lever for the sugar tablet among the rats in pain, even with the painful stimuli still present.
In additional experiments, the researchers were also able to restore the activity of the dopamine neurons by reversing the pain-induced hyperactivity of the GABA neurons. Doing so restored the motivation of rats that were experiencing pain to prefer a sweet solution of sucrose over water, indicating an improvement in their ability to feel pleasure, despite being in pain.
To the authors’ knowledge, this is the first time it has been reported that pain promotes increased activity of GABA neurons and an “inhibitory pathway” in the reward system of the brain from the RMTg, which causes decreased activity of dopamine cells.
“Pain has primarily been studied at peripheral sites and not in the brain, with a goal of reducing or eliminating the sensory component of pain. Meanwhile, the emotional component of pain and associated comorbidities such as depression, anxiety, and lack of ability to feel pleasure that accompany pain has been largely ignored,” said study author Jose Morón-Concepcion, Ph.D., of Washington University in St. Louis.
“It is fulfilling to be able to show pain patients that their mental health and behavioral changes are as real as the physical sensations, and we may be able to treat these changes someday,” added study author Meaghan Creed, Ph.D., of Washington University in St. Louis.
Activation for newly learned words in left medial-temporal lobe during toddlers’ sleep is associated with memory for words
by Elliott Gray Johnson, Lindsey Mooney, Katharine Graf Estes, Christine Wu Nordahl, Simona Ghetti in Current Biology
Very young children learn words at a tremendous rate. Now researchers at the Center for Mind and Brain at the University of California, Davis, have for the first time seen how specific brain regions activate as two-year-olds remember newly learned words — while the children were sleeping.
“We can now leverage sleep to look at basic mechanisms of learning new words,” said Simona Ghetti, professor at the Center for Mind and Brain and UC Davis Department of Psychology.
At two to three years old, children enter a unique age in memory development, Ghetti said. But young children are challenging to study, and they especially dislike being in a functional MRI scanner.
“The scariest things to small children are darkness and loud noises, and that’s what it’s like during an MRI scan,” Ghetti said.
Ghetti’s team had previously found that if children fell asleep in a scanner while it wasn’t working, they could later start the scan and see brain activation in response to songs the children had heard earlier.
In the new study, they looked at how toddlers retained memories of words.
Graduate student Elliott Johnson and Ghetti created a series of made-up, but realistic sounding words as names for a series of objects and puppets. In the first session, two-year-olds were introduced to two objects and two puppets, then tested on their memory of the names after a few minutes. A week later, they returned and were tested on whether they remembered the names of the objects and puppets. Soon after the second test, they slept overnight in an MRI scanner. The researchers played back the words the children had learned, as well as other words, as they slept.
The researchers found activation of the hippocampus and the anterior medial temporal lobe when the sleeping children were played words they had previously learned. This activation correlated with how well they had performed when they initially learned the words a week earlier.
“This suggests that the hippocampus is particularly important for laying down the initial memory for words,” Ghetti said. “This compares quite well with findings from older children and adults, where the hippocampus is associated with learning and with recalling recent memories” Johnson added.
Although young children are rapidly forming memories of new words, they are also losing a lot of memories. When we form a memory, it includes the context: where, when, what else was going on. But if we just learned the name of an object, we don’t need to remember the context to use the word again. That extra detail can go.
It’s not clear how children remember some things, such as names, while losing the rest. Ghetti suspects that overlapping learning experiences interfere with each other and cancel out the unneeded details. Future research will focus on the memory processes that support these changes.
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