Posts tagged brain
Articles and news from the latest research reports.
Your Unconscious Brain Can Do Math, Process Language
The unconscious brain may not be able to ace an SAT test, but new research suggests that it can handle more complex language processing and arithmetic tasks than anyone has previously believed. According to these findings, just published in the Proceedings of the National Academy of Sciences, we may be blithely unaware of all the hard work the unconscious brain is doing.
In their experiments, researchers from Hebrew University in Israel used a cutting-edge “masking” technique to keep their test subjects from consciously perceiving certain stimuli. With this technique, known as continuous flash suppression, the researchers show a rapidly changing series of colorful patterns to just one of the subject’s eyes. The bright patterns dominate the subject’s awareness to such an extent that when researchers show less flashy material to the other eye (like words or equations), it takes several seconds before the brain consciously registers it.
This masking technique is “a game changer in the study of the unconscious,” the scientists write, “because unlike all previous methods, it gives unconscious processes ample time to engage with and operate on subliminal stimuli.”
To study the unconscious brain’s ability to process language, the researchers subliminally showed the subject short phrases that made variable amounts of sense: For example, subjects might see the phrase “I ironed coffee” or “I ironed clothes.” The researchers gradually turned up the contrast between the phrase and its background, and measured how long it took for the phrase to “pop” into the subject’s conscious awareness. As the nonsensical phrases popped sooner, the researchers hypothesize that the unconscious brain processed the sentence, found it surprising and odd, and quickly passed it along to the conscious brain for further examination.
To determine the unconscious brain’s mathematical abilities, the researchers presented a simple subtraction or addition equation (for example, “9 − 3 − 4 = “) to a subject, but took it away before it could pop into consciousness. Then they stopped the masking pattern and displayed a single number, asking the viewer to pronounce the number as soon as it registered. When the number was the answer to the subtraction equation (for example, “2”), the subject was quicker to pronounce it. The researchers argue that the viewer was “primed” to respond to that number because the unconscious brain had solved the equation. Oddly, they didn’t find the same clear effect with easier addition equations.
(Source: spectrum.ieee.org)
Brain-damaged man ‘aware’ of scientists’ questions
A crash victim thought to have been in a vegetative state for more than a decade has used the power of thought to tell scientists he is not in pain.
Canadian Scott Routley, from London, Ontario, communicated with researchers via a brain scan, proving that he is conscious and aware. It is the first time such a severely brain-damaged patient has been able to provide clinically relevant information to doctors.
British neuroscientist Professor Adrian Owen, who leads the research team at the Brain and Mind Institute of Western Ontario, said: “Scott has been able to show he has a conscious, thinking mind. We have scanned him several times and his pattern of brain activity shows he is clearly choosing to answer our questions. We believe he knows who and where he is.”
Prof Owen was speaking on a BBC Panorama programme to be broadcast on Tuesday night.
Research suggests that humans are slowly but surely losing intellectual and emotional abilities
Human intelligence and behavior require optimal functioning of a large number of genes, which requires enormous evolutionary pressures to maintain. A provocative hypothesis published in a recent set of Science and Society pieces published in the Cell Press journal Trends in Genetics (1, 2) suggests that we are losing our intellectual and emotional capabilities because the intricate web of genes endowing us with our brain power is particularly susceptible to mutations and that these mutations are not being selected against in our modern society.
"The development of our intellectual abilities and the optimization of thousands of intelligence genes probably occurred in relatively non-verbal, dispersed groups of peoples before our ancestors emerged from Africa," says the papers’ author, Dr. Gerald Crabtree, of Stanford University. In this environment, intelligence was critical for survival, and there was likely to be immense selective pressure acting on the genes required for intellectual development, leading to a peak in human intelligence.
Bluebrain is a ten-year documentary film-in-the-making about the twenty-first century race to reverse engineer the human brain. Such is the goal of The Blue Brain Project, based in Lausanne, Switzerland, one of the highest-profile neuroscience projects in the world today. Blue Brain’s audacious leader is Henry Markram, who publicly announced in 2009 that he seeks to reverse-engineer a human brain with digital simulations of all the physical properties of every neuron, powered by IBM supercomputers, by 2020. Director Noah Hutton began shooting in 2009, focusing exclusively on Markram’s Blue Brain Project— but starting in Year 3, the scope of the film has expanded to include the work of other prominent projects and labs seeking to understand the brain through different methods, including Sebastian Seung of M.I.T., Rafael Yuste of Columbia University, and Jeff Lichtman of Harvard University.
The film will continue to survey the work of other projects and their leaders in years to come, with yearly shorts released ahead of a full re-edit into a documentary feature due for completion in 2020. As the Blue Brain simulation is built over the course of this decade, so too will this documentary about a historic quest in human history. Through yearly updates from Blue Brain and other prominent scientists, philosophers, and ethicists, Bluebrain will track a crucial decade in the human mind’s relentless drive to understand itself.
Early stress may sensitize girls’ brains for later anxiety
High levels of family stress in infancy are linked to differences in everyday brain function and anxiety in teenage girls, according to new results of a long-running population study by University of Wisconsin-Madison scientists.
The study highlights evidence for a developmental pathway through which early life stress may drive these changes. Here, babies who lived in homes with stressed mothers were more likely to grow into preschoolers with higher levels of cortisol, a stress hormone. In addition, these girls with higher cortisol also showed less communication between brain areas associated with emotion regulation 14 years later. Last, both high cortisol and differences in brain activity predicted higher levels of adolescent anxiety at age 18.
The young men in the study did not show any of these patterns.
"We wanted to understand how stress early in life impacts patterns of brain development which might lead to anxiety and depression,” says first author Dr. Cory Burghy of the Waisman Laboratory for Brain Imaging and Behavior. "Young girls who, as preschoolers, had heightened cortisol levels, go on to show lower brain connectivity in important neural pathways for emotion regulation — and that predicts symptoms of anxiety during adolescence."
To test this, scans designed by Dr. Rasmus Birn, assistant professor of psychiatry in the UW School of Medicine and Public Health, showed that teenage girls whose mothers reported high levels of family stress when the girls were babies show reduced connections between the amygdala or threat center of the brain and the ventromedial prefrontal cortex, a part of the brain responsible for emotional regulation. Birn used a method called resting-state functional connectivity (fcMRI), which looks at the brain connections while the brain is at a resting state.
The study was published in Nature Neuroscience.
Newborn Neurons — Even in the Adult Aging Brain - are Critical for Memory
Newly generated, or newborn neurons in the adult hippocampus are critical for memory retrieval, according to a study led by Stony Brook University researchers published online in Nature Neuroscience. The functional role of newborn neurons in the brain is controversial, but in “Optical controlling reveals time-dependent roles for adult-born dentate granule cells,” the researchers detail that by ‘silencing’ newborn neurons, memory retrieval was impaired. The findings support the idea that the generation of new neurons in the brain may be crucial to normal learning and memory processes.
Previous research by the study’s lead investigator Shaoyu Ge, PhD, Assistant Professor in the Department of Neurobiology & Behavior at Stony Brook University, and others have demonstrated that newborn neurons form connections with existing neurons in the adult brain. To help determine the role of newborn neurons, Dr. Ge and colleagues devised a new optogenetic technique to control newborn neurons and test their function in the hippocampus, one of the regions of the brain that generates new neurons, even in the adult aging brain.
“Significant controversy has surrounded the functional role of newborn neurons in the adult brain,” said Dr. Ge. “We believe that our study results provide strong support to the idea that new neurons are important for contextual fear memory and spatial navigation memory, two essential aspects of memory and learning that are modified by experience.
“Our findings could also shed light on the diagnosis and treatment of conditions common to the adult aging brain, such as dementia and Alzheimer’s disease,” he said.
New form of brain plasticity: Study shows how social isolation disrupts myelin production
Research may prompt new investigations into white matter’s role in psychiatric disorders as well as connections between mood and myelin diseases, like MS
Animals that are socially isolated for prolonged periods make less myelin in the region of the brain responsible for complex emotional and cognitive behavior, researchers at the University at Buffalo and Mt. Sinai School of Medicine report in Nature Neuroscience online.
The research sheds new light on brain plasticity, the brain’s ability to adapt to environmental changes. It reveals that neurons aren’t the only brain structures that undergo changes in response to an individual’s environment and experience, according to one of the paper’s lead authors, Karen Dietz, PhD, research scientist in the Department of Pharmacology and Toxicology in the UB School of Medicine and Biomedical Sciences.
Dietz did the work while a postdoctoral researcher at Mt. Sinai School of Medicine; Jia Liu, PhD, a Mt. Sinai postdoctoral researcher, is the other lead author.
The paper notes that changes in the brain’s white matter, or myelin, have been seen before in psychiatric disorders, and demyelinating disorders have also had an association with depression. Recently, myelin changes were also seen in very young animals or adolescents responding to environmental changes.
"This research reveals for the first time a role for myelin in adult psychiatric disorders," Dietz says. "It demonstrates that plasticity in the brain is not restricted to neurons, but actively occurs in glial cells, such as the oligodendrocytes, which produce myelin."
(Source: eurekalert.org)
Fat cells store excess energy and signal these levels to the brain. In a new study this week in Nature Medicine, Georgios Paschos PhD, a research associate in the lab of Garret FitzGerald, MD, FRS director of the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, shows that deletion of the clock gene Arntl, also known as Bmal1, in fat cells, causes mice to become obese, with a shift in the timing of when this nocturnal species normally eats. These findings shed light on the complex causes of obesity in humans.
The Penn studies are surprising in two respects. “The first is that a relatively modest shift in food consumption into what is normally the rest period for mice can favor energy storage,” says Paschos. “Our mice became obese without consuming more calories.” Indeed, the Penn researchers could also cause obesity in normal mice by replicating the altered pattern of food consumption observed in mice with a broken clock in their fat cells.
This behavioral change in the mice is somewhat akin to night-eating syndrome in humans, also associated with obesity and originally described by Penn’s Albert Stunkard in 1955.
The second surprising observation relates to the molecular clock itself. Traditionally, clocks in peripheral tissues are thought to follow the lead of the “master clock” in the SCN of the brain, a bit like members of an orchestra following a conductor. “While we have long known that peripheral clocks have some capacity for autonomy – the percussionist can bang the drum without instructions from the conductor – here we see that the orchestrated behavior of the percussionist can, itself, influence the conductor,” explains FitzGerald.
Inflammation for Regeneration
The secret to zebrafish’s remarkable capacity for repairing their brains is inflammation, according to a report published online in Science. Neural stem cells in the fish’s brains express a receptor for inflammatory signaling molecules, which prompt the cells to multiply and develop into new neurons.
“This is a very interesting paper,” said Guo-li Ming, a professor of neurology and neuroscience at The Johns Hopkins University in Baltimore, who was not involved in the study. “It is well known that fish have this ability to self-repair, and this paper provides a mechanism,” she said.
Zebrafish, like many other vertebrates, are able to regenerate a variety of body tissues, including their brains. In fact, said Michael Brand, a professor of developmental genetics at the Technische Universität in Dresden, Germany, “mammals are the ones that seem to have lost this ability—they are kind of the odd ones out.” Given the therapeutic potential of neuron regeneration for patients with brain or spinal injuries, “we’d like to figure out if we can somehow reactivate this potential in humans,” Brand said.
Brain Power: From Neurons to Networks is a 10-minute film and an accompanying TED Book. Based on new research on how to best nurture children’s brains from Harvard University’s Center on the Developing Child and University of Washington’s I-LABS, the film explores the parallels between a child’s brain development and the development of the global brain of Internet, offering insights into the best ways to shape both. The film and TEDBook launched at the California Academy of Sciences on November 8, 2012.