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Brain ripples may help bind information across the human cortex: Ubiquitous bursts of brain waves appear to synchronize disparate and distant elements of memory, unifying them upon recollection -- ScienceDaily

The UC San Diego team, led by Halgren, found that ripples also occur in all areas of the human cortex, in waking as well as sleep. The ripples were brief, lasting roughly one-tenth of a second, and had a consistent narrow frequency close to 90 cycles per second. The authors calculated that a typical brief ripple event may involve approximately 5,000 small modules becoming active simultaneously, distributed across the cortical surface. This work is part of the doctoral thesis in neurosciences by first author Charles W. Dickey. "Remarkably, the ripples co-occurred and synchronized across all lobes and between both hemispheres, even at long distances," said Dickey. "Cortical neurons increased firing during ripples, at the ripple rhythm, potentially supporting interaction between distant locations. "There were more co-occurrences preceding successful memory recall. All of which suggests that distributed, cortical co-ripples promote the integration of different elements that may comprise a particular experiential memory."

Scent of a friend: Similarities in body odor may contribute to social bonding: An electronic nose relying on body odor chemistry may predict whether we are likely to 'click' with a stranger -- ScienceDaily

ilar to their own. To test her hypothesis, Ravreby recruited pairs of click friends: same-sex nonromantic friends whose friendships had originally formed very rapidly. She hypothesized that because such friendships emerge prior to an in-depth acquaintance, they may be particularly influenced by physiological traits such as body odor. She then collected body odor samples from these click friends and conducted two sets of experiments to compare the samples with those collected from random pairs of individuals. In one set of experiments, she performed the comparison using the eNose, which assessed the chemical signatures of the odors. In the other, she asked volunteers to smell the two groups of body odor samples in order to assess similarities measured by human perception. In both types of experiments, click friends were found to smell significantly more like each other than did the individuals in the random pairs.

We're Beginning to Understand the Power of Eye Contact  | Discover Magazine

Hirsch’s experiments have also revealed the unique tendency for two brains to synchronize during eye contact and verbal communication. “They become kind of phase-locked in a coherent state,” she says of this dyad brain activity. Emerging research out of Dartmouth has similarly highlighted pupil synchrony in the eyes. Researchers Thalia Wheatley, an expert in social brain science, and Sophie Wohltjen published a study last fall exploring the nuances of eye contact and “shared attention” during conversations. Interestingly, they found that precise moments of shared eye contact actually decrease the pupil synchrony between two people, perhaps in a beneficial way.  They hypothesize that this function can spark unexpected variation that enlivens an interaction. “Eye contact may usefully disrupt synchrony momentarily in order to allow for a new thought or idea,” Wheatley said in a press release about the study.

Anesthetic drastically diverts the travels of brain waves -- ScienceDaily

Imagine the conscious brain as a sea roiling with the collisions and dispersals of waves of different sizes and shapes, swirling around and flowing across in many different directions. Now imagine that an ocean liner lumbers through, flattening everything that trails behind with its powerful, parting wake. A new study finds that unconsciousness induced by the commonly used drug propofol has something like that metaphorical effect on higher frequency brain waves, appearing to sweep them aside and, as an apparent consequence, sweeping consciousness away as well.

A spouse's education can positively impact their partner's overall health -- ScienceDaily

They found that the effect of spousal education on a person's self-assessed overall health is positive and relatively large, suggesting that people benefit from having more highly educated partners in the same way (and to roughly the same extent) that they benefit from being highly educated themselves. This pattern was especially pronounced among women, whose health was more closely tied to spousal education than men's. This finding, Hernandez said, could reflect the time period (1960s-1970s) in which most of the respondents completed their education, married and entered the labor force.

When people 'click' they respond faster to each other: Study reveals the science of connection -- ScienceDaily

Do outside observers also use response times to infer when two people "click?" To test this, respondents from Amazon's Mechanical Turk listened to audio clips of conversations for which the response times had been manipulated to be faster, slower or the original speed (control condition). Consistent with the results from the earlier two studies, outside observers thought two speakers were more connected when their conversations contained faster rather than slower response times. Because these conversation clips were identical except for response times, this study demonstrates that response times alone are a powerful signal of social connection. "It's well-established that, on average, there's about a quarter of a second gap between turns during a conversation. Our study is the first to look at how meaningful that gap is, in terms of connection," says senior author Thalia Wheatley, the Lincoln Filene Professor in Human Relations at Dartmouth, and principal investigator of the Dartmouth Social Systems Laboratory. "When people feel like they can almost finish each other's sentences, they close that 250-millisecond gap, and that's when two people are clicking."

Long-term stress in dogs linked to the owner-dog relationship -- ScienceDaily

"The results showed that the owner's personality affected the stress level in hunting dogs, but interestingly enough not in the ancient dogs. In addition, the relationship between the dog and the owner affected the stress level of the dogs. This was the case for both types, but the result was less marked for the ancient dogs," says Lina Roth, senior lecturer in the Department of Physics, Chemistry and Biology at Linköping University. In a previous study, the same researchers had seen that dogs from herding breeds, which have been genetically selected for their ability to collaborate with humans, mirror the long-term stress level of their owner. When the researchers now added information about the relationship of the herding dogs to their owner, it became clear that the relationship was significant for the long-term stress levels also in these dogs.

Anesthesia doesn't simply turn off the brain, it changes its rhythms -- ScienceDaily

"All the cortex has to be on the same page to produce consciousness," Miller said. "One theory about how this works is through thalamo-cortical loops that allow the cortex to synchronize. Propofol may be breaking the normal operation of those loops by hyper synchronizing them in prolonged down states. It disrupts the ability of the cortex to communicate." For instance, by making measurements in distinct layers of the cortex, the team found that higher frequency "gamma" rhythms, which are normally associated with new sensory information like sights and sounds, were especially reduced in superficial layers. Lower frequency "alpha" and "beta" waves, which Miller has shown tend to regulate the processing of the information carried by gamma rhythms, were especially reduced in deeper layers.

Salad or cheeseburger? Your co-workers shape your food choices -- ScienceDaily

When co-workers are eating together, individuals are more likely to select foods that are as healthy -- or unhealthy -- as the food selections on their fellow employees' trays. "We found that individuals tend to mirror the food choices of others in their social circles, which may explain one way obesity spreads through social networks," says Douglas Levy, PhD, an investigator at the Mongan Institute Health Policy Research Center at Massachusetts General Hospital (MGH) and first author of new research published in Nature Human Behaviour. Levy and his co-investigators discovered that individuals' eating patterns can be shaped even by casual acquaintances, evidence that corroborates several multi-decade observational studies showing the influence of people's social ties on weight gain, alcohol consumption and eating behavior.

Hypnosis changes the way our brain processes information -- ScienceDaily

"In a normal waking state, different brain regions share information with each other, but during hypnosis this process is kind of fractured and the various brain regions are no longer similarly synchronised," describes researcher Henry Railo from the Department of Clinical Neurophysiology at the University of Turku. The finding shows that the brain may function quite differently during hypnosis when compared to a normal waking state. This is interesting because the extent to which hypnosis modifies neural processing has been hotly debated in the field. The new findings also help to better understand which types of changes and mechanisms may explain the experiential and behavioural alterations attributed to hypnosis, such as liability to suggestions. The study focused on a single person who has been extensively studied earlier and been shown to react strongly to hypnotic suggestions. During hypnosis, this person can experience phenomena that are not typically possible in a normal waking state, such as vivid and controlled hallucinations.

Brain waves guide us in spotlighting surprises -- ScienceDaily

By measuring thousands of neurons along the surface, or cortex, of the brain in animals as they reacted to predictable and surprising images, the researchers observed that low frequency alpha and beta brain waves, or rhythms, originating in the brain's frontal cognitive regions tamped down neural activity associated with predictable stimuli. That paved the way for neurons in sensory regions in the back of the brain to push forward information associated with unexpected stimuli via higher-frequency gamma waves. The backflow of alpha/beta carrying inhibitory predictions typically channeled through deeper layers of the cortex, while the forward flow of excitatory gamma carrying novel stimuli propagated across superficial layers.

Scientists find neurochemicals have unexpectedly profound roles in the human brain: Dopamine, serotonin involved in sub-second perception, cognition -- ScienceDaily

"An enormous number of people throughout the world are taking pharmaceutical compounds to perturb the dopamine and serotonin transmitter systems to change their behavior and mental health," said P. Read Montague, senior author of the study and a professor and director of the Center for Human Neuroscience Research and the Human Neuroimaging Laboratory at the Fralin Biomedical Research Institute at Virginia Tech Carilion. "For the first time, moment-to-moment activity in these systems has been measured and determined to be involved in perception and cognitive capacities. These neurotransmitters are simultaneously acting and integrating activity across vastly different time and space scales than anyone expected." Better understanding of the underlying actions of dopamine and serotonin during perception and decision-making could deliver important insight into psychiatric and neurological disorders, the researchers said. "Every choice that someone executes involves taking in information, interpreting that information, and making decisions about what they perceived," said Kenneth Kishida, a corresponding author of the study and an assistant professor of physiology and pharmacology, and neurosurgery, at Wake Forest School of Medicine. "There's a whole host of psychiatric conditions and neurological disorders where that process is altered in the patients, and dopamine and serotonin are prime suspects."

Two-person-together MRI scans on couples investigates how touching is perceived in the brain: An MRI in each other's arms shows how physical contact alters the brains of couples -- ScienceDaily

"During social interaction, people's brains are literally synchronised. The associated mental imitation of other people's movements is probably one of the basic mechanisms of social interaction. The new technology now developed will provide totally new opportunities for studying the brain mechanisms of social interaction," says Professor Lauri Nummenmaa from Turku PET Centre.

Flickering light mobilizes brain chemistry that may fight Alzheimer's -- ScienceDaily

n 2016, researchers discovered that light flickering at 40 Hz mobilized microglia in mice afflicted with Alzheimer's to clean up that junk. The new study looked for brain chemistry that connects the flicker with microglial and other immune activation in mice and exposed a surge of 20 cytokines -- small proteins secreted externally by cells and which signal to other cells. Accompanying the cytokine release, internal cell chemistry -- the activation of proteins by phosphate groups -- left behind a strong calling card. "The phosphoproteins showed up first. It looked as though they were leading, and our hypothesis is that they triggered the release of the cytokines," said Singer, who co-led the new study and is an assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory.

Gut reaction: How immunity ramps up against incoming threats -- ScienceDaily

Eating causes a hormone called VIP to kickstart the activity of immune cells in response to potentially incoming pathogens or 'bad' bacteria. The researchers also found that immunity increased at anticipated mealtimes indicating that maintaining regular eating patterns could be more important than previously thought. With the rise in conditions associated with chronic inflammation in the gut, such as irritable bowel and Crohn's disease, a better understanding of the early protective mechanisms governing gut health could help researchers to develop prevention strategies against unwanted inflammation and disease.

Your Life is Driven by Network Effects

Compatibility between two people in terms of their individual characteristics is sometimes much less important than the compatibility between their networks. This is one possible reason why there is a surprisingly low divorce rate amongst arranged matches made solely on the basis of compatibility between kin networks.

In mice, alcohol dependence results in brain-wide remodeling of functional architecture -- ScienceDaily

"The neuroscience of addiction has made tremendous progress, but the focus has always been on a limited number of brain circuits and neurotransmitters, primarily dopaminergic neurons, the amygdala and the prefrontal cortex," said senior author Olivier George, PhD, associate professor in the Department of Psychiatry at UC San Diego School of Medicine. "Research groups have been fighting for years about whether 'their' brain circuit is the key to addiction. Our results confirm these regions are important, but the fact that we see such a massive remodeling of the functional brain architecture was a real shock. It's like studying the solar system and then discovering that there is an entire universe behind it. It shows that if you really want to understand the neurobiological mechanisms leading to addiction, you can't just look at a handful of brain regions, you need to look at the entire brain, you need to take a step back and consider the whole organ." George said the findings further undermine the idea that addiction is simply a psychological condition or consequence of lifestyle. "You would be surprised at how prevalent this view remains," he said. "The brain-wide remodeling of the functional architecture observed here is not 'normal.' It is not observed in a naïve animal. It is not observed in an animal that drinks recreationally. It is only observed in animals with a history of alcohol dependence and it is massive. Such a decrease in brain modularity has been observed in numerous brain disorders, including Alzheimer's disease, traumatic brain injury and seizure disorders." Brain modularity is the theory that there are functionally specialized regions in the brain responsible for different, specific cognitive processes. For example, the frontal lobes of the human brain are involved in executive functions, such as reasoning and planning, while the fusiform face area located in the lower rear of the brain is involved in recognizing faces. Reduced modularity, said George, likely interferes with "normal neuronal activity and information processing and contributes to cognitive impairment, emotional distress and intense craving observed in mice during abstinence from alcohol." Due to the format of the testing, George said it was not clear if the reduced modularity was permanent. "So far, we only know that it lasts at least one week into abstinence. We have not tested longer durations of abstinence, but it's one of our goals."

Baby and adult brains 'sync up' during play: It's not your imagination -- you and your baby really are on the same wavelength -- ScienceDaily

When they looked at the data, the researchers found that during the face-to-face sessions, the babies' brains were synchronized with the adult's brain in several areas known to be involved in high-level understanding of the world -- perhaps helping the children decode the overall meaning of a story or analyze the motives of the adult reading to them. When the adult and infant were turned away from each other and engaging with other people, the coupling between them disappeared. That fit with researchers' expectations, but the data also had surprises in store. For example, the strongest coupling occurred in the prefrontal cortex, which is involved in learning, planning and executive functioning and was previously thought to be quite underdeveloped during infancy. "We were also surprised to find that the infant brain was often 'leading' the adult brain by a few seconds, suggesting that babies do not just passively receive input but may guide adults toward the next thing they're going to focus on: which toy to pick up, which words to say," said Lew-Williams, who is a co-director of the Princeton Baby Lab.

What your friends' brains look like when they think of you: Your brain patterns are reflected in them, study finds -- ScienceDaily

The fMRI took images of each person's brain while they completed a task similar to the one they did earlier. They rated each of their friends and themselves on 48 traits, including lonely, sad, cold, lazy, overcritical, trustworthy, enthusiastic, clumsy, fashionable, helpful, smart, punctual and nice. As they expected from previous research, the researchers saw activity in the medial prefrontal cortex, a part of the brain implicated in thinking about the self and close others, as the participants thought about the personality traits of themselves and their friends. The study found that for each participant, the combined brain activity of their friends evaluating them looked a lot like their own brain activity. This suggests that order to accurately perceive another person, your neural representation of that person -- your patterns of brain activity for their identity -- has to essentially match the pattern in that persons' brain when they are thinking about themselves, Wagner said.

In Alzheimer's research, scientists reveal brain rhythm role -- ScienceDaily

In 2016, Tsai and colleagues showed that Alzheimer's disease model mice exposed to a light flickering at 40 Hz for an hour a day for a week had significantly less buildup of amyloid and tau proteins in the visual cortex, the brain region that processes sight, than experimental control mice did. Amyloid plaques and tangles of phosphorylated tau are both considered telltale hallmarks of Alzheimer's disease. But the study raised new questions: Could GENUS prevent memory loss? Could it prevent the loss of neurons? Does it reach other areas of the brain? And could other senses be stimulated for beneficial effect? The new studies addressed those questions. In March, the team reported that sound stimulation reduced amyloid and tau not only in the auditory cortex, but also in the hippocampus, a crucial region for learning and memory. GENUS-exposed mice also performed significantly better on memory tests than unstimulated controls. Simultaneous light and sound, meanwhile, reduced amyloid across the cortex, including the prefrontal cortex, a locus of cognition.

Molecule links weight gain to gut bacteria -- ScienceDaily

The study also found that microbes program these so-called circadian rhythms by activating a protein named histone deacetylase 3 (HDAC3), which is made by cells that line the gut. Those cells act as intermediaries between bacteria that aid in digestion of food and proteins that enable absorption of nutrients. The study, done in mice, revealed that HDAC3 turns on genes involved in the absorption of fat. They found that HDAC3 interacts with the biological clock machinery within the gut to refine the rhythmic ebb and flow of proteins that enhance absorption of fat. This regulation occurs in the daytime in humans, who eat during the day, and at night in mice, which eat at night. "The microbiome actually communicates with our metabolic machinery to make fat absorption more efficient. But when fat is overabundant, this communication can result in obesity. Whether the same thing is going on in other mammals, including humans, is the subject of future studies," added lead author Dr. Zheng Kuang, a postdoctoral fellow in the Hooper laboratory.

Perception of musical pitch varies across cultures: How people interpret musical notes depends on the types of music they have listened to -- ScienceDaily

This question has been hard to answer, in part because of the difficulty in finding people who have not been exposed to Western music. Now, a new study led by researchers from MIT and the Max Planck Institute for Empirical Aesthetics has found that unlike residents of the United States, people living in a remote area of the Bolivian rainforest usually do not perceive the similarities between two versions of the same note played at different registers (high or low). The findings suggest that although there is a natural mathematical relationship between the frequencies of every "C," no matter what octave it's played in, the brain only becomes attuned to those similarities after hearing music based on octaves, says Josh McDermott, an associate professor in MIT's Department of Brain and Cognitive Sciences.

Sunflowers found to share nutrient-rich soil with others of their kind

In the first study, the researchers placed isolated sunflower plants near a rich food source and watched how it behaved. As expected, the plant sent more roots into the area, allowing it to consume more nutrients. But they also found that when they placed two sunflower plants an equal distance from the same food source, both sent fewer roots than they would have were they alone. This was a clear sign that the plants were not only aware of the presence of the other, but were working together to allow both of them to gain the greatest benefit. In another experiment, the researchers placed sunflower plants at different distances from the rich soil patch and found that the sunflower nearest the soil patch sent out just as many new roots as if it were isolated. In other experiments, the researchers planted multiple plants at different distances from the nutrient-rich patch to see how they would respond. They report that plants that were growing with a neighbor actually decreased root length in such shared patches—and they did not increase them when they were close to very high-quality soil areas. The researchers conclude that sunflowers work together to gain the most benefit from the soil for themselves and for those around them.

Brain waves detected in mini-brains grown in a dish -- ScienceDaily

The pea-sized brains, called cerebral organoids, are derived from human pluripotent stem cells. By putting them in culture that mimics the environment of brain development, the stem cells differentiate into different types of brain cells and self-organize into a 3D structure resembling the developing human brain. Scientists have successfully grown organoids with cellular structures similar to those of human brains. However, none of the previous models developed human-like functional neural networks. Networks appear when neurons are mature and become interconnected, and they are essential for most brain activities. "You can use brain organoids for several things, including understand normal human neurodevelopment, disease modeling, brain evolution, drug screening, and even to inform artificial intelligence," Muotri says. Muotri and colleagues designed a better procedure to grow stem cells, including optimizing the culture medium formula. These adjustments allowed their organoids to become more mature than previous models. The team grew hundreds of organoids for 10 months and used multi-electrode arrays to monitor their neural activities. The team began to detect bursts of brain waves from organoids at about two months. The signals were sparse and had the same frequency, a pattern seen in very immature human brains. As the organoids continued to grow, they produced brain waves at different frequencies, and the signals appeared more regularly. This suggests the organoids have further developed their neural networks.

Neuroscientists discover neuron type that acts as brain's metronome: By keeping the brain in sync, these long-hypothesized but never-found neurons help rodents to detect subtle sensations -- ScienceDaily

This type of neuron spikes rhythmically, and in a synchronized manner, independent of external sensations, said Chris Moore, a professor of neuroscience at Brown and the associate director of the Carney Institute for Brain Science. By "setting the beat," the neurons appear to improve rodents' ability to detect when their whiskers are lightly tapped. Brain waves with approximately 40 cycles per second -- also known as gamma rhythms -- have been studied since the mid-1930s in humans and rodents, and earlier work from Moore's lab showed that boosting the rodents' natural gamma rhythms helped the rodents detect fainter whisker sensations. "Gamma rhythms have been a huge topic of debate," Moore said. "Some greatly respected neuroscientists view gamma rhythms as the magic, unifying clock that align signals across brain areas. There are other equally respected neuroscientists that, colorfully, view gamma rhythms as the exhaust fumes of computation: They show up when the engine is running but they're absolutely not important." The metronome-like function of the gamma rhythm has been hypothesized before, but has been largely written off because gamma rhythms change in response to sensations, Moore added. These newly discovered spiking "metronome" neurons -- which spike around 40 cycles a second -- do not.

Decentralizing science may lead to more reliable results in biomedical research: Analysis of data on tens of thousands of drug-gene interactions -- ScienceDaily

"The way science is often produced may inadvertently contribute to unreliable results," says senior author James Evans, Professor of Sociology at the University of Chicago, and External Professor at the Santa Fe Institute, US. "For example, a large group of scientists who frequently collaborate, use similar methods, share equipment, and frequently cite similar works are prone to producing the same, self-confirming results. Although such a group may produce repeated published experiments, our results demonstrate that their findings are not independent. Independent labs perform experiments in different ways with different expectations and are less prone to peer pressure than a densely connected networks of scientists."