Posts Tagged ‘MRI’


Signals long thought to be “noise” appear to represent a distinct form of brain activity.

By Tanya Lewis

Every few seconds a wave of electrical activity travels through the brain, like a large swell moving through the ocean. Scientists first detected these ultraslow undulations decades ago in functional magnetic resonance imaging (fMRI) scans of people and other animals at rest—but the phenomenon was thought to be either electrical “noise” or the sum of much faster brain signals and was largely ignored.

Now a study that measured these “infraslow” (less than 0.1 hertz) brain waves in mice suggests they are a distinct type of brain activity that depends on an animal’s conscious state. But big questions remain about these waves’ origin and function.

An fMRI scan detects changes in blood flow that are assumed to be linked to neural activity. “When you put someone in a scanner, if you just look at the signal when you don’t ask the subject to do anything, it looks pretty noisy,” says Marcus Raichle, a professor of radiology and neurology at Washington University School of Medicine in St. Louis and senior author of the new study, published in April in Neuron. “All this resting-state activity brought to the forefront: What is this fMRI signal all about?”

To find out what was going on in the brain, Raichle’s team employed a combination of calcium/hemoglobin imaging, which uses fluorescent molecules to detect the activity of neurons at the cellular level, and electrophysiology, which can record signals from cells in different brain layers. They performed both measurements in awake and anesthetized mice; the awake mice were resting in tiny hammocks in a dark room.

The team found that infraslow waves traveled through the cortical layers of the awake rodents’ brains—and changed direction when the animals were anesthetized. The researchers say these waves are distinct from so-called delta waves (between 1 and 4 Hz) and other higher-frequency brain activity.

These superslow waves may be critical to how the brain functions, Raichle says. “Think of, say, waves on the water of Puget Sound. You can have very rough days where you have these big groundswells and then have whitecaps sitting on top of them,” he says. These “swells” make it easier for brain areas to become active—for “whitecaps” to form, in other words.

Other researchers praised the study’s general approach but were skeptical that it shows the infraslow waves are totally distinct from other brain activity. “I would caution against jumping to a conclusion that resting-state fMRI is measuring some other property of the brain that’s got nothing to do with the higher-frequency fluctuations between areas of the cortex,” says Elizabeth Hillman, a professor of biomedical engineering at Columbia University’s Zuckerman Institute, who was not involved in the work. Hillman published a study in 2016 finding that resting-state fMRI signals represent neural activity across a range of frequencies, not just low ones.

More studies are needed to tease apart how these different types of brain signals are related. “These kinds of patterns are very new,” Hillman notes. “We haven’t got much of a clue what they are, and figuring out what they are is really, really difficult.”

https://www.scientificamerican.com/article/superslow-brain-waves-may-play-a-critical-role-in-consciousness1/

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An international team of researchers has linked specific symptoms of schizophrenia with various anatomical characteristics in the brain, according to research published in NeuroImage.

By analyzing the brain’s anatomy with magnetic resonance imaging (MRI), researchers from the University of Granada, Washington University in St. Louis, and the University of South Florida have demonstrated the existence of distinctive subgroups among patients with schizophrenia who suffer from different symptoms.

These findings could herald a significant step forward in diagnosing and treating schizophrenia.

To perform the study, the researchers conducted the MRI technique “diffusion tensor imaging” on 36 healthy participants and 47 schizophrenic participants.

The researchers found that tests on schizophrenic participants revealed various abnormalities in parts of the corpus callosum, a bundle of neural fibers that connects the left and right cerebral hemispheres and is essential for effective interhemispheric communication.

Different anomalies in the corpus callosum were associated with different symptoms in the schizophrenic participants. An anomaly in one part of the brain structure was associated with strange and disorganized behavior; another anomaly was associated with disorganized thought and speech, as well as negative symptoms such as a lack of emotion; and other anomalies were associated with hallucinations.

In 2014, this same research group proved that schizophrenia is not a single illness. The team demonstrated the existence of 8 genetically distinct disorders, each with its own symptoms. Igor Zwir, PhD, and Javier Arnedo from the University of Granada’s Department of Computer Technology and Artificial Intelligence found that different sets of genes were strongly linked with different clinical symptoms.

“The current study provides further evidence that schizophrenia is a heterogeneous group of disorders, as opposed to a single illness, as was previously thought to be case,” Dr Zwir said in a statement.

While current treatments for schizophrenia tend to be generic regardless of the symptoms exhibited by each patient, the researchers believe that in the future, analyzing how specific gene networks are linked to various brain features and specific symptoms will help develop treatments that are adapted to each patient’s individual disorder.

To conduct the analysis of the gene groups and brain scans, the researchers developed a new, complex analysis of the relationships between different types of data and recommendations regarding new data. The system is similar to that used by companies such as Netflix to determine what movies they want to broadcast.

“To conduct the research, we did not begin by studying individuals who had certain schizophrenic symptoms in order to determine whether they had the corresponding brain anomalies,” said Dr Zwir in a statement. “Instead, we first analyzed the data, and that’s how we discovered these patterns. This type of information, combined with data on the genetics of schizophrenia, will someday be of vital importance in helping doctors treat the disorders in a more precise and effective way.”

Reference
Arnedo J, Mamah D, Baranger DA, et al. Decomposition of brain diffusion imaging data uncovers latent schizophrenias with distinct patterns of white matter anisotropy. NeuroImage. 2015; doi:10.1016/j.neuroimage.2015.06.083.

http://www.psychiatryadvisor.com/schizophrenia-and-psychoses/types-subgroups-schizophrenia-linked-various-different-brain-anomalies-corpus-callosum/article/470226/?DCMP=EMC-PA_Update_rd&cpn=psych_md&hmSubId=&hmEmail=5JIkN8Id_eWz7RlW__D9F5p_RUD7HzdI0&NID=&dl=0&spMailingID=13630678&spUserID=MTQ4MTYyNjcyNzk2S0&spJobID=720090900&spReportId=NzIwMDkwOTAwS0

Mother-child MRI

Posted: December 15, 2015 in brain
Tags: , , , ,

While most new moms get their children’s first portrait done at, say, the local mall’s JC Penney Portrait Studio, neuroscientist Rebecca Saxe opted for a slightly different location: the tube of an MRI scanner.

“No one, to my knowledge, had ever made an MR image of a mother and child,” she wrote in a article for Smithsonian magazine.

“We made this one because we wanted to see it.”

A Professor of Cognitive Neuroscience at the Massachusetts Institute of Technology, Saxe told Mic that the inspiration behind the photo had little to do with the typical medical or research-based uses of MRI technology.

“We see brain scan images on TV and in subways advertisements as a proxy for technology and progress… [and] the Madonna is one of the oldest tropes in human art making,” she said of trying to capture the union between science and art in the image.

“These brain scanners are extremely modern technology, only available here and now, to the wealthiest place and time in human history,” she added. “[Yet] the image you see would look the same if it had been made on any continent or in any century, because the biology of human mothers and children you see in the picture has been the same for thousands, probably tens of thousands of years.”

In an interview with Today, Saxe suggested that the image may be indicative of how a child’s brain development is strengthened by a mother’s love. “Some people look at it and see mostly the differences: how thin his skull is, how little space there is between the outside world and his brain. It’s just this very fragile, very thin little shell,” she said. “On the other hand, you can look at it and see how similar it is to his mother’s brain. How close in size — so much closer in size than his hand is.”

Past MRI scans have also suggested that the bond between a child and mother can indeed have a major impact on brain size. Back in 2012, a side-by-side image of two three-year-olds’ brain scans indicated that the size of a neglected child’s brain is significantly smaller than one who was nurtured by his or her mother. Of that particular image, neurology professor Allan Schore told the Telegraph that the development of brain cells is a “consequence of an infant’s interaction with the main caregiver [usually the mother].”

Meanwhile, Saxe believes that the image can also help generate an interest in science. “I hope the main takeaway is that people who don’t normally feel a human connection to science and scientists, have a moment to pause and feel touched, and recognize that the scientific pursuit of self-knowledge is being done for, and by, people like us,” she told Mic.

http://mic.com/articles/130456/this-brain-scan-image-illustrates-the-powerful-bond-between-mother-and-child#.tkqP2UYTE

Scientific tests have revealed that an ancient Buddhist statue contains the perfectly preserved remains of a 1,000-year-old mummified monk, in what is believed to be the only such example in the world.

The monk, who is sitting in the lotus position, is thought to have starved himself to death in an act of extreme spiritual devotion in China or Tibet in the 10th century. His preserved remains were displayed in his monastery.

Some 200 years later, perhaps after his remains started to deteriorate, his mummified body was placed inside the elaborate, lacquered statue of Buddha.

The unusual contents of the statue were discovered in the 1990s when the statue underwent restoration. Experts were unable to remove the mummy due to the risk of disintegration, so they could do little more than peer into the darkened cavity of the Buddha.

Now, an international team of German, Dutch and Italian scientists has conducted a CAT scan which revealed the monk’s skeleton in perfect detail.

“It was not uncommon for monks to practise self-mummification but to find a mummified monk inside a statue is really extraordinary,” said Wilfrid Rosendahl, a German palaeontologist who led the research. “It’s the only known example in the world.

“Using a CAT scan, we saw that there was a perfectly preserved body with skin and muscles inside the statue. It’s a complete mummy, not just a skeleton. He was aged between 30 and 50.”

The mummy has been studied by an interdisciplinary team of experts, including radio carbon dating specialists and textile analysts, at the Meander Medical Centre in Amersfoort, the Netherlands.

Using an endoscope, experts took samples from inside the mummy’s thoracic and abdominal cavities and discovered that the monk’s organs had been removed and replaced with ancient wads of paper printed with Chinese characters.

Samples of bone were also taken for DNA testing.

The Buddha statue was bought several decades ago on the art market by a Dutch private collector, who had no idea that the mummy was hidden inside.

It will go on display in museums around Europe, and is currently in the Natural History Museum in Budapest.

“The monk died in a process of self-mummification,” said Dr Rosendahl.

“During the last weeks he would have started eating less food and drinking only water. Eventually he would have gone into a trance, stopped breathing and died. He basically starved himself to death.

“The other monks would have put him close to a fire to dry him out and put him on display in the monastery, we think somewhere in China or Tibet.

“He was probably sitting for 200 years in the monastery and the monks then realised that he needed a bit of support and preservation so they put him inside the statue.”

Mummified monks were not only the focus of religious devotion, but important for the economy of the monastery because they attracted pilgrims who would offer donations.

Mummified-monk-revealed-inside-1000-year-old-Buddha-statue

Thanks to Steven Weihing for bringing this to the attention of the It’s Interesting community.

Everyone knows it’s easier to learn about a topic you’re curious about. Now, a new study reveals what’s going on in the brain during that process, revealing that such curiosity may give a person a memory boost.

When participants in the study were feeling curious, they were better at remembering information even about unrelated topics, and brain scans showed activity in areas linked to reward and memory.

The results, detailed October 2 in the journal Neuron, hint at ways to improve learning and memory in both healthy people and those with neurological disorders, the researchers said.

“Curiosity may put the brain in a state that allows it to learn and retain any kind of information, like a vortex that sucks in what you are motivated to learn, and also everything around it,” Matthias Gruber, a memory researcher at the University of California, Davis, said in a statement. “These findings suggest ways to enhance learning in the classroom and other settings.”

Gruber and his colleagues put people in a magnetic resonance imaging (MRI) scanner and showed them a series of trivia questions, asking them to rate their curiosity about the answers to those questions. Later, the participants were shown selected trivia questions, then a picture of a neutral face during a 14-second delay, followed by the answer. Afterward, the participants were given a surprise memory test of the faces, and then a memory test of the trivia answers.

Not surprisingly, the study researchers found that people remembered more information about the trivia when they were curious about the trivia answers. But unexpectedly, when the participants were curious, they were also better at remembering the faces, an entirely unrelated task. Participants who were curious were also more likley than others to remember both the trivia information and unrelated faces a day later, the researchers found.

The brain scans showed that, compared with when their curiosity wasn’t piqued, when people were curious, they showed more activation of brain circuits in the nucleus accumbens, an area involved in reward. These same circuits, mediated by the neurochemical messenger dopamine, are involved in forms of external motivation, such as food, sex or drug addiction.

Finally, being curious while learning seemed to produce a spike of activity in the hippocampus, an area involved in forming new memories, and strengthened the link between memory and reward brain circuits.

The study’s findings not only highlight the importance of curiosity for learning in healthy people, but could also give insight into neurological conditions. For example, as people age, their dopamine circuits tend to deteriorate, so understanding how curiosity affects these circuits could help scientists develop treatments for patients with memory disorders, the researchers said.

http://www.livescience.com/48121-curiosity-boosts-memory-learning.html