The moment a person slips from conscious thought into unconsciousness has long been a mystery.

Now researchers have pinpointed exactly what goes on in the brain as people become unconscious after taking anesthesia. It turns out that there probably aren't individual neurons, or brain cells, responsible for consciousness.

"This data shows that consciousness might not be the result of a special group of neurons, but rather might be the result of how neurons communicate with one another," study co-author Martin Monti, a psychology professor at the University of California at Los Angeles, wrote in an email.

When people are conscious, information zips from one place to another along a direct route, much like an express bus, whereas the way information travels in the unconscious brain is more like taking several buses and stopping in North Dakota and Tennessee to get from New York to Los Angeles, Monti said.

Bold and outgoing or shy and retiring - - while many people can shift from one to the other as circumstances warrant, in general they lean toward one disposition or the other. And that inclination changes little over the course of their lives.

Why this is the case and why it matters in a more traditional context are questions being addressed by anthropologists at UC Santa Barbara. Using fertility and child survivorship as their main measures of reproductive fitness, the researchers studied over 600 adult members of the Tsimane, an isolated indigenous population in central Bolivia, and discovered that more open, outgoing - - and less anxious - - personalities were associated with having more children - - but only among men.

Their findings appear online in the journal Evolution and Human Behavior.

"The idea that we're funneled into a relatively fixed way of interacting with the world is something we take for granted," said Michael Gurven, UCSB professor of anthropology and the paper's lead author. Gurven is also co-director of the University of New Mexico-based Tsimane Health and Life History Project. "Some people are outgoing and open, others are more quiet and introverted. But from an evolutionary standpoint, it doesn't really make sense that our dispositions differ so much, and are not more flexible.

Childhood poverty and chronic stress may lead to problems regulating emotions as an adult, according to research published online in the Proceedings of the National Academy of Sciences.

"Our findings suggest that the stress-burden of growing up poor may be an underlying mechanism that accounts for the relationship between poverty as a child and how well your brain works as an adult," said Dr. K. Luan Phan, professor of psychiatry at University of Illinois at Chicago College of Medicine and senior author of the study.

The study was conducted by researchers at UIC, Cornell University, University of Michigan and University of Denver.

The researchers found that test subjects who had lower family incomes at age 9 exhibited, as adults, greater activity in the amygdala, an area in the brain known for its role in fear and other negative emotions. These individuals showed less activity in areas of the prefrontal cortex, an area in the brain thought to regulate negative emotion.

Older adults are often encouraged to stay active and engaged to keep their minds sharp, that they have to "use it or lose it." But new research indicates that only certain activities - learning a mentally demanding skill like photography, for instance - are likely to improve cognitive functioning.

These findings, forthcoming in Psychological Science, a journal of the Association for Psychological Science, reveal that less demanding activities, such as listening to classical music or completing word puzzles, probably won't bring noticeable benefits to an aging mind.

"It seems it is not enough just to get out and do something - it is important to get out and do something that is unfamiliar and mentally challenging, and that provides broad stimulation mentally and socially," says psychological scientist and lead researcher Denise Park of the University of Texas at Dallas. "When you are inside your comfort zone you may be outside of the enhancement zone."

The new findings provide much-needed insight into the components of everyday activities that contribute to cognitive vitality as we age.

"We need, as a society, to learn how to maintain a healthy mind, just like we know how to maintain vascular health with diet and exercise," says Park. "We know so little right now."

For their study, Park and colleagues randomly assigned 221 adults, ages 60 to 90, to engage in a particular type of activity for 15 hours a week over the course of three months.

Some participants were assigned to learn a new skill - digital photography, quilting, or both - which required active engagement and tapped working memory, long-term memory and other high-level cognitive processes.

In the movie Groundhog Day, the TV weatherman Phil Connors finds himself living the same day again and again. This has its advantages, as he has hundreds of chances to get things right. He can learn to speak French, to sculpt ice, to play jazz piano, and to become the kind of person with whom his beautiful colleague Rita might fall in love. But it's a torment, too. An awful solitude flows from the fact that he's the only one in Punxsutawney, Pennsylvania, who knows that something has gone terribly wrong with time. Nobody else seems to have any memory of all the previous iterations of the day. What is a new day for Rita is another of the same for Phil. Their realities are different - what passes between them in Phil's world leaves no trace in hers - as are their senses of selfhood: Phil knows Rita as she cannot know him, because he knows her day after day after day, while she knows him only today. Time, reality, and identity are each curated by memory, but Phil's and Rita's memories work differently. From Phil's point of view, she, and everyone else in Punxsutawney, is suffering from amnesia.

Amnesia comes in distinct varieties. In "retrograde amnesia," a movie staple, victims are unable to retrieve some or all of their past knowledge - Who am I? Why does this woman say that she's my wife? - but they can accumulate memories for everything that they experience after the onset of the condition. In the less cinematically attractive "anterograde amnesia," memory of the past is more or less intact, but those who suffer from it can't lay down new memories; every person encountered every day is met for the first time. In extremely unfortunate cases, retrograde and anterograde amnesia can occur in the same individual, who is then said to suffer from "transient global amnesia," a condition that is, thankfully, temporary. Amnesias vary in their duration, scope, and originating events: brain injury, stroke, tumors, epilepsy, electroconvulsive therapy, and psychological trauma are common causes, while drug and alcohol use, malnutrition, and chemotherapy may play a part.

In findings that give fresh meaning to the old adage that a good night's sleep clears the mind, a new study shows that a recently discovered system that flushes waste from the brain is primarily active during sleep. This revelation could transform scientists' understanding of the biological purpose of sleep and point to new ways to treat neurological disorders.

"This study shows that the brain has different functional states when asleep and when awake," said Maiken Nedergaard, M.D., D.M.Sc., co-director of the University of Rochester Medical Center (URMC) Center for Translational Neuromedicine and lead author of the article. "In fact, the restorative nature of sleep appears to be the result of the active clearance of the by-products of neural activity that accumulate during wakefulness."

The study, which was published today in the journal Science, reveals that the brain's unique method of waste removal - dubbed the glymphatic system - is highly active during sleep, clearing away toxins responsible for Alzheimer's disease and other neurological disorders. Furthermore, the researchers found that during sleep the brain's cells reduce in size, allowing waste to be removed more effectively.

The purpose of sleep is a question that has captivated both philosophers and scientists since the time of the ancient Greeks. When considered from a practical standpoint, sleep is a puzzling biological state. Practically every species of animal from the fruit fly to the right whale is known to sleep in some fashion. But this period of dormancy has significant drawbacks, particularly when predators lurk about. This has led to the observation that if sleep does not perform a vital biological function then it is perhaps one of evolution's biggest mistakes.

Individuals suffering with schizophrenia are subject to a whole host of disturbing, life-changing symptoms. They can range from disorganized thinking and an inability to plan for the future to full-on hallucinations and paranoid delusions. Through treatment with psychiatric therapy and medication can be effective for some, the psychiatric disease has largely remained a medical mystery.

However, researchers at the RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory at MIT have uncovered what they term "a faulty brain mechanism" they believe is crucial in the eventual development of schizophrenia and other psychiatric disorders in humans.

Speaking about the study published in today's issue of Neuron, Susumu Tonegawa, director at RIKEN-MIT said, "Our study provides new insight into what underlies schizophrenia's disordered thinking and zeroes in on a new target for future investigation into the neural basis of a cognitive disorder that affects more than 1 percent of the world's population." Tonegawa is also a senior author of the study.

This study, like many others in the fields of genetics, was an animal study. The team employed the use of genetically engineered mice that displayed symptoms of schizophrenia. One difficulty faced by this study, in particular, was figuring out how to model the complex nature of disorganized thought in the mice.

If you're happy and you know it, clap your hands! That's easy enough for children to figure out because the emotion matches the movement. But when feelings and reactions don't align, can kids tell there's something wrong? New research from Concordia University proves that they can - as early as 18 months.

In a study recently published in Infancy: The Official Journal of the International Society on Infant Studies, psychology researchers Sabrina Chiarella and Diane Poulin-Dubois demonstrate that infants can detect whether a person's emotions are justifiable given a particular context. They prove that babies understand how the meaning of an experience is directly linked to the expressions that follow.


The implications are significant, especially for caregivers. "Our research shows that babies cannot be fooled into believing something that causes pain results in pleasure. Adults often try to shield infants from distress by putting on a happy face following a negative experience. But babies know the truth: as early as 18 months, they can implicitly understand which emotions go with which events," says psychology professor Poulin-Dubois.

Surprising USC study shows that brains process the pain of villains more than the pain of people we like.

Counterintuitive findings from a new USC study show that the part of the brain that is associated with empathizing with the pain of others is activated more strongly by watching the suffering of hateful people as opposed to likable people.

While one might assume that we would empathize more with people we like, the study may indicate that the human brain focuses more greatly on the need to monitor enemies closely, especially when they are suffering.

"When you watch an action movie and the bad guy appears to be defeated, the moment of his demise draws our focus intensely," said Lisa Aziz-Zadeh of the Brain and Creativity Institute of the USC Dornsife College of Letters, Arts and Sciences. "We watch him closely to see whether he's really down for the count, because it's critical for predicting his potential for retribution in the future."

Aziz-Zadeh, who has a joint appointment with the USC Division of Occupational Science and Occupational Therapy, collaborated with lead author Glenn Fox, a PhD candidate at USC; and Mona Sobhani, formerly a grad student at USC and who is now a post-doctoral researcher at Vanderbilt University, on a study that appears in Frontiers in Psychology this month.

The study examined activity in the so-called "pain matrix" of the brain, a network that includes the insula cortex, the anterior cingulate, and the somatosensory cortices - regions known to activate when an individual watches another person suffer.

Schizophrenia patients usually suffer from a breakdown of organized thought, often accompanied by delusions or hallucinations. For the first time, MIT neuroscientists have observed the neural activity that appears to produce this disordered thinking.

The researchers found that mice lacking the brain protein calcineurin have hyperactive brain-wave oscillations in the hippocampus while resting, and are unable to mentally replay a route they have just run, as normal mice do.

Mutations in the gene for calcineurin have previously been found in some schizophrenia patients. Ten years ago, MIT researchers led by Susumu Tonegawa, the Picower Professor of Biology and Neuroscience, created mice lacking the gene for calcineurin in the forebrain; these mice displayed several behavioral symptoms of schizophrenia, including impaired short-term memory, attention deficits, and abnormal social behavior.

In the new study, which appears in the Oct. 16 issue of the journal Neuron, Tonegawa and colleagues at the RIKEN-MIT Center for Neural Circuit Genetics at MIT's Picower Institute for Learning and Memory recorded the electrical activity of individual neurons in the hippocampus of these knockout mice as they ran along a track.

Previous studies have shown that in normal mice, "place cells" in the hippocampus, which are linked to specific locations along the track, fire in sequence when the mice take breaks from running the course. This mental replay also occurs when the mice are sleeping. These replays occur in association with very high frequency brain-wave oscillations known as ripple events.

In mice lacking calcineurin, the researchers found that brain activity was normal as the mice ran the course, but when they paused, their ripple events were much stronger and more frequent. Furthermore, the firing of the place cells was abnormally augmented and in no particular order, indicating that the mice were not replaying the route they had just run.

This pattern helps to explain some of the symptoms seen in schizophrenia, the researchers say.