Tag Archives: research

How The Brain Maintains Memories

01 Wednesday Feb 2023

Posted by in brain

≈ Leave a comment

Tags

,

A team of neuroscientists at the University of Toronto in Canada has discovered a reason why we often struggle to remember small details of past experiences.

Many events in our lives resemble experiences we have had before, without being identical to them.

Whenever you attend a party, for example, you may well take along a gift, such as a bottle of wine or a box of chocolates, but the gift will differ on each occasion.

Researchers believe that as our memories for such events become older, the incidental details unique to each event (such as the identity of the gift) are mostly forgotten.

However, the common underlying patterns (what parties are like in general) are retained. This allows us to accumulate knowledge to guide our behavior in similar situations in the future.

Studies in rodents and people have shown that a region of the brain called the medial prefrontal cortex (mPFC) stores long-term memories about experiences.

But to what extent do neurons in this region represent abstract generalized knowledge as opposed to the specific incidental details?

“Memories of recent experiences are rich in incidental detail but, with time, the brain is thought to extract important information that is common across various past experiences,” said Dr. Kaori Takehara-Nishiuchi, senior author of the study.

“We predicted that groups of neurons in the mPFC build representations of this information over the period when long-term memory consolidation is known to take place, and that this information has a larger representation in the brain than the smaller details.”

To test their prediction, Dr. Takehara-Nishiuchi and her colleagues studied how two different memories with overlapping associative features are coded by neuron groups in the mPFC of rat brains, and how these codes change over time.

Rats were given two experiences with an interval between each: one involving a light and tone stimulus, and the other involving a physical stimulus. This gave them two memories that shared a common stimulus relationship.

The researchers then tracked the neuron activity in the animals’ brains from the first day of learning to four weeks following their experiences.

“This experiment revealed that groups of neurons in the mPFC initially encode both the unique and shared features of the stimuli in a similar way,” said Mark Morrissey, first author on the study.

“However, over the course of a month, the coding becomes more sensitive to the shared features and less sensitive to the unique features, which become lost.”

Further experiments also revealed that the brain can adapt the general knowledge gained from multiple experiences immediately to a new situation.

“This goes some way to answering the long-standing question of whether the formation of generalized memory is simply a result of the brain’s network ‘forgetting’ incidental features,” Morrissey said.

“On the contrary, we show that groups of neurons develop coding to store shared information from different experiences while, seemingly independently, losing selectivity for irrelevant details.”

“The unique coding property of the mPFC identified in the study may support its role in the formation, maintenance, and updating of associative knowledge structures that help support flexible and adaptive behavior in rats and other animals,” he said. 

Brain Scan May Help Decide Treatment for Depression

07 Wednesday Dec 2022

Posted by in brain, Depression

≈ Leave a comment

Tags

New research from Emory University in Atlanta has found that specific patterns of activity on brain scans may help clinicians identify whether psychotherapy or antidepressant medication is more likely to help individual patients recover from depression.

The study, called PReDICT, randomly assigned patients to 12 weeks of treatment with one of two antidepressant medications or with cognitive behavioral therapy (CBT).

At the start of the study, patients underwent a functional MRI brain scan, which was then analyzed to see whether the outcome from CBT or medication depended on the state of the brain prior to starting treatment.

The MRI scans identified that the degree of functional connectivity between an important emotion processing center — the subcallosal cingulate cortex — and three other areas of the brain was associated with the treatment outcomes, according to the researchers.

Specifically, patients with positive connectivity between the brain regions were significantly more likely to achieve remission with CBT, while patients with negative or absent connectivity were more likely to benefit from antidepressant medication.

“All depressions are not equal and like different types of cancer, different types of depression will require specific treatments. Using these scans, we may be able to match a patient to the treatment that is most likely to help them, while avoiding treatments unlikely to provide benefit,” said Helen Mayberg, M.D., a professor of psychiatry, neurology and radiology at Emory University School of Medicine.

Mayberg and her co-investigators, Boadie Dunlop, M.D., director of the Emory Mood and Anxiety Disorders Program, and W. Edward Craighead, Ph.D., a professor of psychiatry and behavioral sciences, sought to develop methods for a more personalized approach to treating depression.

Current treatment guidelines for major depression recommend that a patient’s preference for psychotherapy or medication be considered in selecting the initial treatment approach. However, in the PReDICT study, patients’ preferences were only weakly associated with outcomes — preferences predicted treatment drop-out, but not improvement, the study found.

These results are consistent with prior studies, suggesting that achieving personalized treatment for depressed patients will depend more on identifying specific biological characteristics in patients rather than relying on their symptoms or treatment preferences, the researchers noted.

The results from PReDICT suggest that brain scans may offer the best approach for personalizing treatment going forward, they add.

The researchers recruited 344 patients for the study from across the metro Atlanta area. Researchers note they were able to convene a more diverse group of patients than other previous studies, with roughly half of the participants self-identified as African American or Hispanic.

“Our diverse sample demonstrated that the evidence-based psychotherapy and medication treatments recommended as first-line treatments for depression can be extended with confidence beyond a white, non-Hispanic population,” said Dunlop.

“Ultimately our studies show that clinical characteristics, such as age, gender, etc., and even patients’ preferences regarding treatment, are not as good at identifying likely treatment outcomes as the brain measurement,” concluded Mayberg.

The study results were published in the American Journal of Psychiatry.

Arts appear to play role in brain development

09 Wednesday Nov 2022

Posted by in brain

≈ Leave a comment

Tags

,

Brain research in the past several years is just beginning to uncover some startling ideas about how students learn. First came the proof, some years ago, that our brains do not lose brain cells as we get older, but are always capable of growing.

Now neuroscientists are investigating how training students in the arts may change the structure of their brains and the way they think. They are asking: Does putting a violin in the hands of an elementary school student help him to do math better? Will learning to dance or paint improve a child’s spacial ability or ability to learn to read?

Research in those areas, Harvard professor Jerome Kagan said, is “as deserving of a clinical trial as a drug for cancer that has not yet been shown to be effective.”

There aren’t many conclusions yet that can be translated into the classroom, but there is an emerging interdisciplinary field between education and neuroscience. Like Hopkins, Harvard also has created a center to study learning and the brain.

Much of the research into the arts has centered on music and the brain. One researcher studying students who go to an arts high school found a correlation between those who were trained in music and their ability to do geometry. Yet another four-year study, being conducted by Ellen Winner of Boston College and Gottfried Schlaug of Harvard, is looking at the effects playing the piano or the violin has on students who are in elementary school.

Winner said she was quite skeptical of claims that schools that had introduced the arts had seen an increase in test scores and a generally better school climate. She had previously looked at those claims and found they couldn’t be backed up by research.

However, she is in the midst of a four-year study of elementary students that has shown some effects: One group is learning an instrument, and another is not. “It is the first study to demonstrate brain plasticity in young children related to music playing,” Schlaug said.

The study Winner is working on has shown that children who receive a small amount of training — as little as half an hour of lessons a week and 10 minutes of practice a day — do have structural changes in their brains that can be measured. And those students, Winner said, were better at tests that required them to use their fingers with dexterity.

About 15 months after the study began, students who played the instrument were not better at math or reading, although the researchers are questioning whether they have assessments that are sensitive enough to measure the changes. They will continue the study for several more years.

Charles Limb, a Johns Hopkins doctor and a jazz musician, studied jazz musicians by using imaging technology to take pictures of their brains as they improvised. He found that they allowed their creativity to flow by shutting down areas that regulated inhibition and self-control. So are the most creative people able to shut down those areas of the brain?

Most of the new research is focusing on the networks of the brain that are involved in specific tasks, said Michael Posner, a researcher at the University of Oregon. Posner has studied the effects of music on attention. What he found, he said, was that in those students who showed motivation and creativity, training in the arts helped develop their attention and their intelligence. The next great focus in this area, he said, is on proving the connection that most scientists believe exists between the study of music and math ability.

The imaging is now so advanced that scientists can already see the difference in the brain networks of those who study a string instrument and those who study the piano intensely.

The brain research, while moving quickly by some measures, is still painfully slow for educators who would like answers today. Morgan, the Washington County schools chief, said some research did help her support the drive to build the Barbara Ingram School for the Arts in Hagerstown.

Mariale Hardiman, the former principal of Roland Park Elementary/Middle School, was once one of those principals who focused a lot of attention on reading and math scores. But she saw what integrating the arts into classrooms could do for students, she said, and she then began her own research into the subject.

She is now the co-director of the Hopkins Neuro-Education Initiative. She said there are a myriad of questions that could be answered in the research that is just starting, but there are two she would like to see approached: Do children who learn academic content through the arts tend to hold onto that knowledge longer? And are schools squeezing creativity out of children by controlling so much of their school day?

Even without research though, Kagan of Harvard said there is ample evidence of the value of an arts education because so many children who aren’t good at academics can gain self-confidence through the arts.

“The argument for an arts education is based not on sentimentality but on pragmatism,” he said. “If an arts program only helped the 7 million children in the bottom quartile, the dropout rate would drop.”

Research Identifies How Stress Triggers Relapse

05 Wednesday Oct 2022

Posted by in Addiction, brain, Stress

≈ Leave a comment

Tags

,

Recent research from Brown University could pave the way for new methods of treatment for those recovering from addiction. Researchers identified an exact brain region in rats where the neural steps leading to drug relapse take place, allowing them to block a crucial step in the process that leads to stress-induced relapse.

Prior research has established that acute stress can lead to drug abuse in vulnerable individuals and increase the risk of relapse in recovering addicts. But the exact way that stress triggers the neural processes leading to relapse is still not clearly understood. The Brown study provides new insights on how stress triggers drug abuse and could lead to more effective treatments for addiction.

According to the study, stress has significant effects on plasticity of the synapses on dopamine neurons in the ventral tegmental area (VTA), the brain region where the neural activities leading to a stress-induced drug relapse take place.

Stress activates kappa opioid receptors (KORs) in the VTA, and the researchers found that by blocking the KORs, they could prevent the rats from relapsing to cocaine use while under stress.

Published in the journal Neuron, the study shows blocking these receptors may be a critical step in preventing stress-related drug relapses in humans, as well. The chemical used to block the receptor, “nor-BMI,” may eventually be tested on humans, according to the study’s authors.

“If we understand how kappa opioid receptor antagonists are interfering with the reinstatement of drug seeking, we can target that process,” senior study author Julie Kauer said in a statement. “We’re at the point of coming to understand the processes and possible therapeutic targets. Remarkably, this has worked.”

Kauer noted that the study builds upon over a decade of research on how changes in brain synapses relate to behaviors like addiction. The advance is significant and could accelerate progress towards a medication for those struggling to recover from addiction.

“If we can figure out how not only stress, but the whole system works, then we’ll potentially have a way to tune it down in a person who needs that,” Kauer said.

US-European Satellite Will Make World’s First Global Freshwater Survey

02 Friday Sep 2022

Posted by in Research

≈ Leave a comment

Tags

,

https://nasa.gov/feature/jpl/us-european-satellite-will-make-world-s-first-global-freshwater-survey

“A collaboration between NASA and the French space agency Centre National d’Études Spatial (CNES), with contributions from the Canadian Space Agency and the United Kingdom Space Agency, SWOT is scheduled to launch in November from Vandenberg Space Force Base in California.“

“SWOT has several key tasks, including measuring the height of water bodies on Earth’s surface. Over the ocean, the satellite will be able to “see” features like eddies less than 60 miles (100 kilometers) across – smaller than those that previous sea level satellites could observe. SWOT will also measure more than 95% of Earth’s lakes larger than 15 acres (6 hectares) and rivers wider than 330 feet (100 meters) across.”

via #NASA_APP

Depression and the inflammatory process

29 Wednesday Dec 2021

Posted by in Depression, Mental Health, Research, Uncategorized

≈ Leave a comment

Tags

, ,

Most people feel down, tired and inactive when they’re injured or ill. This “sickness behavior” is caused by the activation of the body’s immune response. It’s the brain’s way of conserving energy so the body can heal.

This immune response can also occur in people with depression. This has prompted some researchers and clinicians to hypothesise that depression is actually a side effect of the inflammatory process.

But while there may be a connection between inflammation and depression, one doesn’t necessarily lead to the other. So it’s too simplistic to say depression is a physical, rather than a psychiatric, illness.

The inflammation hypothesis

University of California clinical psychologist and researcher George Slavich is one of the key recent proponents of depression as a physical illness. He hypothesises that social threats and adversity trigger the production of pro-inflammatory “cytokines”. These are messenger molecules of the immune system that play a critical role in orchestrating the host’s response to injury and infection.

This inflammatory process, Slavich argues, can initiate profound behavioral changes, including the induction of depression.

5241352878_f53a343088.jpg

The idea that the activation of the immune response may trigger depression in some people is by no means a new one. Early descriptions of post-influenza depression appeared in the 19th century in the writings of English physician Daniel Tuke.

But it was not until the 1988 seminal paper, published by veterinarian Benjamin Hart, that the phenomenon of acute “sickness behavior” caught the interest of the scientific community.

Hart described his detailed observations of the “behavior of sick animals”. During acute infection, and in response to fever, the animals sought sleep, lost their appetite, showed a reduction in activity, grooming and social interactions, as well as showing signs of “depression”.

Just like the immune response itself, these changes reflect an evolved survival strategy that shifts priorities toward energy conservation and recovery.

Putting the theory into practice

Cytokine-induced sickness behavior has subsequently been studied as an example of communication between the immune system and the brain.

The behavioral changes during sickness resemble those associated with depression, so it didn’t take long for researchers to make a connection between the phenomenon of sickness behavior and mental disorders.

Such speculation was strengthened by research showing that depressive states can be experimentally induced by administering cytokines and other immunogenic agents (such as vaccines) that cause an inflammatory response.

Depression is frequently associated with inflammatory illnesses such as heart disease and rheumatoid arthritis. It’s also a side effect of treatment with cytokines to enhance the immune system.

Over recent decades, researchers have made progress in understanding how inflammation may impact on the activity of signalling pathways to and from the brain, as well as on the functioning of key neural systems involved in mood regulation.

But there’s not always a link

From the available evidence it’s clear, however, that not everyone who suffers from depression has evidence of inflammation. And not all people with high levels of inflammation develop depression.

Trajectories of depression depend on a complex interplay of a spectrum of additional risk and resilience factors, which may be present to varying degrees and in a different combination in any individual at different times. These factors include the person’s:

  • genetic vulnerabilities affecting the intensity of our inflammatory response
  • other medical conditions
  • acquired hyper-vigilance in the stress response systems due to early life trauma, current adversities, or physical stressors
  • coping strategies, including social support
  • health behaviors, such as sleep, diet and exercise.

Implications for treatment

In line with the notion that inflammation drives depression, some researchers have already trialled the effectiveness of anti-inflammatory therapy as a treatment for depression.

While some recipients (such as those with high levels of inflammation) showed benefit from the treatment, others without increased inflammation did not. This supports the general hypothesis.

However, in our desire to find more effective treatments for depression, we should not forget that the immune response, including inflammation, has a specific purpose. It protects us from infection, disease and injury.

Cytokines act at many different levels, and often in subtle ways, to fulfill their numerous roles in the orchestration of the immune response. Undermining their vital role could have negative consequences.

Mind versus body

The recent enthusiasm to embrace inflammation as the major culprit in psychiatric conditions ignores the reality that “depression” is not a single condition. Some depressive states, such as melancholia, are diseases; some are reactions to the environment; some are existential; and some normal.

Such separate states have differing contributions of biological, social and psychological causes. So any attempt to invoke a single all-explanatory “cause” should be rejected. Where living organisms are concerned it is almost never that simple.

In the end, we cannot escape the reality that changes must occur at the level of the brain, in regions responsible for mood regulation, for “depression” to be experienced.