Posts tagged brain
Articles and news from the latest research reports.
Research links ‘brain waves’ to cognition, attention and diagnosing disorders
February 7, 2012
Professor Jason Mattingley, Foundation Chair in Cognitive Neuroscience at The University of Queensland, released his findings into ‘brain waves’ at the Australian Neuroscience Society’s (ANS) annual conference last week.
'Brain waves' are the oscillations produced by the brain, which are thought to contribute to its remarkable capacity to integrate information about the world.
According to Professor Mattingley’s research, brain oscillations can be linked to sleep, navigation, cognition, attention, and to diagnosing a wide range of disorders including autism, schizophrenia and epilepsy.
To understand how the brain filters information during visual attention and perception, Professor Mattingley and his fellow researchers encouraged subjects to perform tasks involving the use of flickering stimuli on a computer display. This included embedding colour-coded visual information to see how well subjects track a specific target colour from a myriad of distracting information.
“Imagine the brain as a stadium full of sports fans. Each spectator is like an individual neuron in the brain. Now imagine the spectators starting a Mexican wave that sweeps through the crowd from one side of the stadium to the other. Our research shows that neurons in the brain act in much the same way. Distinct waves of neural activity, moving at different speeds and in different directions, help coordinate neurons across widely separated areas of the brain,” Professor Mattingley said.
“We can measure these brain waves as people engage in different tasks, such as focusing their attention on just one colour in multi-coloured display. The measurements we take from the brain are a bit like the ripples from a handful of pebbles thrown into a pond.”
“While interesting in their own right, these studies are also relevant to brain dysfunction, as defects in neural responses to flickering visual stimuli have been found in individuals with autism, schizophrenia, and epilepsy, and such oscillations have been found to be significantly altered in aging, depression, and neurodegenerative disorders. Using these tasks may help to both diagnose and understand the basis for differences in brain function in people with these conditions.”
The Australian Neuroscience Society’s (ANS) annual conference brings together researchers in search of a greater understanding of the human nervous system and its functions.
As part of the program around 100 international speakers and delegates shared their insights into the peripheral senses - touch, sight, hearing and smell – perception, cognition, learning and memory, with a particular focus on neurological and neurodegenerative disease.
Provided by University of Queensland
Source: medicalxpress.com
Warning! Collision imminent! The brain’s quick interceptions help you navigate the world
February 7, 2012
Researchers at The Neuro and the University of Maryland have figured out the mathematical calculations that specific neurons employ in order to inform us of our distance from an object and the 3-D velocities of moving objects and surfaces relative to ourselves.
When you are about to collide into something and manage to swerve away just in the nick of time, what exactly is happening in your brain? A new study from the Montreal Neurological Institute and Hospital – The Neuro, McGill University shows how the brain processes visual information to figure out when something is moving towards you or when you are about to head into a collision. The study, published in the Proceedings of the National Academy of Sciences (PNAS), provides vital insight into our sense of vision and a greater understanding of the brain.
Researchers at The Neuro and the University of Maryland have figured out the mathematical calculations that specific neurons employ in order to inform us of our distance from an object and the 3D velocities of moving objects and surfaces relative to ourselves. Highly specialized neurons located in the brain’s visual cortex, in an area known as MST, respond selectively to motion patterns such as expansion, rotation, and deformation. However, the computations underlying such selectivity were unknown until now.
Using mathematical models and sophisticated recording techniques, researchers have discovered how individual MST neurons function. “Area MST is typical of high-level visual cortex, in that information about important aspects of vision can be seen in the firing patterns of single neurons. A classic example is a neuron that only fires when the subject is looking at the image of a particular face. This type of neuron has to gather information from other neurons that are selective to simpler features, like lines, colors, and textures, and combine these pieces of information in a fairly sophisticated way,” says Dr. Christopher Pack, neuroscientist at The Neuro and senior author. “Similarly, for motion detection, neurons have to combine input from many other neurons earlier in the visual pathway, in order to determine whether something is moving toward you or just drifting past.” The brain’s visual pathway is made up of building blocks. For example, neurons in the retina respond to very simple stimuli, such as small spots of light. Further along the visual pathway, neurons respond to more complex stimulus such as straight lines, by combining inputs from neurons earlier on. Neurons further along respond to even more complex stimulus such as combinations of lines (angles), ultimately leading to neurons that can respond to, or recognize, faces and objects for example.
Source: medicalxpress.com
Sharp Images from the Living Mouse Brain
February 6th, 2012
This STED image of a nerve cell in the upper brain layer of a living mouse shows in previously impossible detail the very fine dendritic protrusions of a nerve cell, the so-called spines, at which the synapses are located. The inset shows the mushroom-shaped head of such a dendritic spine at which the nerve cells receive information from their peers. © Max Planck Institute for Biophysical Chemistry
Source: Neuroscience News
It’s not solitaire: Brain activity differs when one plays against others
February 6, 2012
Rock, paper or scissors? Learning while playing a strategic game against others involves a different pattern of brain activity than learning from the consequences of one’s own actions, researchers found. Credit: L. Brian Stauffer
Researchers have found a way to study how our brains assess the behavior – and likely future actions – of others during competitive social interactions. Their study, described in a paper in the Proceedings of the National Academy of Sciences, is the first to use a computational approach to tease out differing patterns of brain activity during these interactions, the researchers report.
"When players compete against each other in a game, they try to make a mental model of the other person’s intentions, what they’re going to do and how they’re going to play, so they can play strategically against them," said University of Illinois postdoctoral researcher Kyle Mathewson, who conducted the study as a doctoral student in the Beckman Institute with graduate student Lusha Zhu and economics professor and Beckman affiliate Ming Hsu, who now is at the University of California, Berkeley. "We were interested in how this process happens in the brain."
Previous studies have tended to consider only how one learns from the consequences of one’s own actions, called reinforcement learning, Mathewson said. These studies have found heightened activity in the basal ganglia, a set of brain structures known to be involved in the control of muscle movements, goals and learning. Many of these structures signal via the neurotransmitter dopamine.
"That’s been pretty well studied and it’s been figured out that dopamine seems to carry the signal for learning about the outcome of our own actions," Mathewson said. "But how we learn from the actions of other people wasn’t very well characterized."
Researchers call this type of learning “belief learning.”
To better understand how the brain processes information in a competitive setting, the researchers used functional magnetic resonance imaging (fMRI) to track activity in the brains of participants while they played a competitive game, called a Patent Race, against other players. The goal of the game was to invest more than one’s opponent in each round to win a prize (a patent worth considerably more than the amount wagered), while minimizing one’s own losses (the amount wagered in each trial was lost). The fMRI tracked activity at the moment the player learned the outcome of the trial and how much his or her opponent had wagered.
A computational model evaluated the players’ strategies and the outcomes of the trials to map the brain regions involved in each type of learning.
"Both types of learning were tracked by activity in the ventral striatum, which is part of the basal ganglia," Mathewson said. "That’s traditionally known to be involved in reinforcement learning, so we were a little bit surprised to see that belief learning also was represented in that area."
Belief learning also spurred activity in the rostral anterior cingulate, a structure deep in the front of the brain. This region is known to be involved in error processing, regret and “learning with a more social and emotional flavor,” Mathewson said.
The findings offer new insight into the workings of the brain as it is engaged in strategic thinking, Hsu said, and may aid the understanding of neuropsychiatric illnesses that undermine those processes.
"There are a number of mental disorders that affect the brain circuits implicated in our study," Hsu said. "These include schizophrenia, depression and Parkinson’s disease. They all affect these dopaminergic regions in the frontal and striatal brain areas. So to the degree that we can better understand these ubiquitous social functions in strategic settings, it may help us understand how to characterize and, eventually, treat the social deficits that are symptoms of these diseases."
Provided by University of Illinois at Urbana-Champaign
Source: medicalxpress.com
Magnetic research for better brain health
February 6, 2012
A pioneering therapy that uses magnetic pulses to stimulate the brain to treat conditions such as Parkinson’s disease, depression, schizophrenia, epilepsy and stroke is now better understood thanks to researchers from The University of Western Australia and the Université Pierre et Marie Curie in France.
Research Associate Professor Jennifer Rodger from UWA’s School of Animal Biology said she and her team tested the therapy - known as repetitive transcranial magnetic stimulation (rTMS) - on mice to find out how it can be applied to treating human neurological disease.
The research was published recently in the prestigious journal FASEB.
"Our work demonstrated for the first time that pulsed magnetic fields promote changes in brain chemicals that correct abnormal brain connections, resulting in improved behaviour and brain function," joint lead author Dr Rodger said.
"rTMS is an exciting therapy that stimulates the brain. It has shown promising results in treating the damaged human brain. Our research helps to explain how this therapy works on the cells of the brain. Previously, evidence of its usefulness was mainly from anecdotal clinical evidence.
"Our results greatly increase our understanding of the specific cellular and molecular events that occur in the brain during rTMS therapy. We are the first to show that changes in brain circuits underpin these beneficial effects. Our results have implications for how rTMS is used in humans to treat disease and improve brain function."
Dr Rodger explained that the structural and functional changes caused by the therapy in malfunctioning circuits were not seen in the normal healthy brain, suggesting that the therapy could have minimal side effects in humans.
Provided by University of Western Australia
Source: medicalxpress.com
Mom’s Love Good for Child’s Brain
January 30th, 2012
The hippocampus (highlighted in fuchsia) is a key brain structure important to learning, memory and stress response. New research shows that children who were nurtured by their mothers early in life have a larger hippocampus than children who were not nurtured as much. Credit: Washington University Medical School from press release
Source: Neuroscience News
Gender Specific Behavior Traced To Hormone-Controlled Genes In The Brain
Article Date: 06 Feb 2012 - 0:00 PST
Men and women may be equals, but they often behave differently when it comes to sex and parenting. Now a study of the differences between the brains of male and female mice in the Cell Press journal Cell provides insight into how our own brains might be programmed for these stereotypically different behaviors.
The new evidence shows that the sex hormones - testosterone, estrogen, and progesterone - act in a key region of the brain, switching certain genes on and others off. When the researchers tinkered with each of these genes one by one, animals showed subtle but important shifts in individual sex-specific behaviors, such as how males mate or females care for their pups.
“What this means is that complex behaviors like male mating or maternal care in mice can be deconstructed at the genetic level,” said Nirao Shah of the University of California, San Francisco. The findings present a cellular and molecular representation of gender that is remarkable in its complexity, the researchers say.
Shah’s team made these discoveries after screening mouse brains for genes that show differences in expression in males versus females. The researchers focused specifically on the hypothalamus, a region previously implicated in the control of sex-specific behaviors. Their screen produced a list of 16 genes with clear sex differences in distinct neurons in the hypothalamus. Surprisingly, Shah’s team found that many of these genes also show sex differences in the amygdala, a part of the brain important for emotions.
In further studies, the researchers examined the effects of a subset of these individual genes. Mice missing only one of these 16 genes seemed to behave normally. But upon closer observation, these mice showed significant differences in sex-specific behaviors. For instance, Shah explained, females mutant for one gene took longer to return their pups to the nest and to fight off intruders. “They still take care of their pups, but less effectively,” he said.
In other experiments, deletion of a single gene produced females that were two-fold less receptive to mating with males. Similarly, males mutant for another gene were less interested in females. Together these results mean that sex-specific behaviors can be controlled in modular fashion, such that the loss of any one gene leads to subtle but potentially important changes.
“At the superficial level, the mice appear normal, but this is pretty significant variation in behavior,” Shah said. It suggests that variation in such genes might explain not just differences between the sexes, but also differences in behaviors within one sex or the other - why some male mice are more aggressive than other males or some females more attentive to their offspring than other females.
The researchers don’t yet know exactly how these differences in gene expression lead to those differences in behavior, although Shah says some of the genes are known to be involved in sending or receiving neural messages in the brain. It also remains to be seen how the male and female gene expression programs might be influenced by the animals’ social interactions and experiences.
There is still a lot to learn about what makes males and females tick. “This gene list of sex differences in the brain is probably just a small subset of what we will eventually unearth,” Shah said.
Source: Medical News Today
Memory Function - Decaffeinated Coffee May Help
Article Date: 05 Feb 2012 - 0:00 PST
Drinking decaffeinated coffee may improve brain energy metabolism associated with diabetes type 2, according to a study published in Nutritional Neuroscience and carried out by researchers at Mount Sinai School of Medicine. Brain energy metabolism is a dysfunction with a known risk factor for dementia and other neurodegenerative disorders like Alzheimer’s disease.
Giulio Maria Pasinetti, MD, PhD, and team decided to investigate whether dietary supplementation with a standard decaffeinated coffee prior to diabetes onset could improve insulin resistance and glucose utilization in mice with diet-induced type 2 diabetes.
The mice were given the supplement for five months, after which the researchers assessed the animals’ brain’s genetic response. They discovered that the brain could metabolize glucose more effectively and that it was used for cellular energy in the brain. People with type 2 diabetes have reduced glucose utilization in the brain, which often leads to neurocognitive problems.
Dr. Pasinetti stated:
"Impaired energy metabolism in the brain is known to be tightly correlated with cognitive decline during aging and in subjects at high risk for developing neurodegenerative disorders. This is the first evidence showing the potential benefits of decaffeinated coffee preparations for both preventing and treating cognitive decline caused by type 2 diabetes, aging, and/or neurodegenerative disorders."
Drinking coffee is not recommended for everyone, because of its association with cardiovascular health risks, including elevated blood cholesterol and blood pressure, both of which result in a higher risk of developing heart disease, stroke, and premature death. However, these negative effects have mainly been caused because of the high caffeine content of coffee - the study findings prove that some components in decaffeinated coffee have beneficial health factors for mice.
Dr. Pasinetti wants to investigate whether decaffeinated coffee as a dietary supplement in humans can act as a preventive measure.
He concludes:
"In light of recent evidence suggesting that cognitive impairment associated with Alzheimer’s disease and other age-related neurodegenerative disorders may be traced back to neuropathological conditions initiated several decades before disease onset, developing preventive treatments for such disorders is critical."
Petra Rattue
Source: Medical News Today
Hearing Metaphors Activates Brain Regions Involved in Sensory Experience
ScienceDaily (Feb. 3, 2012) — When a friend tells you she had a rough day, do you feel sandpaper under your fingers? The brain may be replaying sensory experiences to help understand common metaphors, new research suggests.
Regions of the brain activated by hearing textural metaphors are shown in green. Yellow and red show regions activated by sensory experience of textures visually and through touch. (Credit: Image courtesy of Emory University)
Linguists and psychologists have debated how much the parts of the brain that mediate direct sensory experience are involved in understanding metaphors. George Lakoff and Mark Johnson, in their landmark work ‘Metaphors we live by’, pointed out that our daily language is full of metaphors, some of which are so familiar (like “rough day”) that they may not seem especially novel or striking. They argued that metaphor comprehension is grounded in our sensory and motor experiences.
New brain imaging research reveals that a region of the brain important for sensing texture through touch, the parietal operculum, is also activated when someone listens to a sentence with a textural metaphor. The same region is not activated when a similar sentence expressing the meaning of the metaphor is heard.
The results were published online this week in the journal Brain & Language.
"We see that metaphors are engaging the areas of the cerebral cortex involved in sensory responses even though the metaphors are quite familiar," says senior author Krish Sathian, MD, PhD, professor of neurology, rehabilitation medicine, and psychology at Emory University. "This result illustrates how we draw upon sensory experiences to achieve understanding of metaphorical language."
Sathian is also medical director of the Center for Systems Imaging at Emory University School of Medicine and director of the Rehabilitation R&D Center of Excellence at the Atlanta Veterans Affairs Medical Center.
Seven college students who volunteered for the study were asked to listen to sentences containing textural metaphors as well as sentences that were matched for meaning and structure, and to press a button as soon as they understood each sentence. Blood flow in their brains was monitored by functional magnetic resonance imaging. On average, response to a sentence containing a metaphor took slightly longer (0.84 vs 0.63 seconds).
In a previous study, the researchers had already mapped out, for each of these individuals, which parts of the students’ brains were involved in processing actual textures by touch and sight. This allowed them to establish with confidence the link within the brain between metaphors involving texture and the sensory experience of texture itself.
"Interestingly, visual cortical regions were not activated by textural metaphors, which fits with other evidence for the primacy of touch in texture perception," says research associate Simon Lacey, PhD, the first author of the paper.
The researchers did not find metaphor-specific differences in cortical regions well known to be involved in generating and processing language, such as Broca’s or Wernicke’s areas. However, this result doesn’t rule out a role for these regions in processing metaphors, Sathian says. Also, other neurologists have seen that injury to various areas of the brain can interfere with patients’ understanding of metaphors.
"I don’t think that there’s only one area responsible for metaphor processing," Sathian says. "Actually, several recent lines of research indicate that engagement with abstract concepts is distributed around the brain." "I think our research highlights the role of neural networks, rather than a single area of the brain, in these processes. What could be happening is that the brain is conducting an internal simulation as a way to understand the metaphor, and that’s why the regions associated with touch get involved. This also demonstrates how complex processes involving symbols, such as appreciating a painting or understanding a metaphor, do not depend just on evolutionarily new parts of the brain, but also on adaptations of older parts of the brain."
Sathian’s future plans include asking whether similar relationships exist for other senses, such as vision. The researchers also plan to probe whether magnetic stimulation of the brain in regions associated with sensory experience can interfere with understanding metaphors.
The research was supported by the National Institutes of Health and the National Science Foundation.
Source: ScienceDaily