Category: Neurofeedback

In this feature, we discuss six studies that uncover new and unexpected truths about the organ we hold in our skulls. Neuroscience is never easy, but the resulting intrigue is worth the effort.

The brain is the pivotal hub of our central nervous system. Through this organ, we take note of the world, we assess our version of reality, we dream, we ponder, we laugh.

Its nervous tendrils permeate every inch of our bodies, innervating, controlling, and monitoring all that we touch, think, and feel.

Its other, more silent, yet vital role is its command over our survival as an organism — our heartbeat, our breathing rate, the release of hormones, and much more.

Because of its vast complexity, it is no surprise that we continuously learn new things about the brain.

In this feature, we will discuss some recent research that shines fresh light on the organ that defines us as individuals, controls our emotions, and retains detailed information about our first pet.

To start, we will take a look at links between the brain and a seemingly unrelated part of the body — the gut.

Brain and gut
At first glance, it seems surprising that our brain and gut are interlinked, but we have all experienced their tight relationship. By way of example, many of us, when especially hungry, might be more easily enraged.

In fact, there is a great deal of neural conversation between the gut and the brain. After all, if the gut is not well fed, it could be a matter of life and death; the brain needs to be informed when energy is low so that it can call other systems into action.

1. Sugar may alter brain chemistry after only 12 days
Recently, Medical News Today published a study that investigated how sugar influenced the brain of a particular breed of swine, known as Göttingen minipigs. For 1 hour each day for 12 days, the pigs had access to sucrose solution.

Before and after the 12-day sugar intervention, the scientists used a PET imaging technique that measured dopamine and opioid activity. They also imaged five of the pigs’ brains after their first sucrose experience.

They chose to focus on the dopamine and opioid systems because both play pivotal roles in pleasure seeking behavior and addiction. One of the authors, Michael Winterdahl, explains what they found:

“After just 12 days of sugar intake, we could see major changes in the brain’s dopamine and opioid systems. In fact, the opioid system, which is that part of the brain’s chemistry that is associated with well-being and pleasure, was already activated after the very first intake.”

The authors published their findings in the journal Scientific Reports. Scientists have debated whether sugar is addictive for decades, but these findings, as the authors explain, suggest that “foods high in sucrose influence brain reward circuitry in ways similar to those observed when addictive drugs are consumed.”

2. Gut bacteria and the brain
Over recent years, gut bacteria and the microbiome at large have become increasingly popular with scientists and laypeople alike. It is no surprise that gut bacteria can influence gut health, but it does come as more of an eye-opener that they might influence our brain and behavior.

Although at first, this idea was a fringe topic, it is now moving closer to the mainstream. However, links between gut bacteria and mental health are still relatively controversial.

Recently, a study appearing in Nature Microbiology utilized data from the Flemish Gut Flora Project, which included 1,070 participants. The scientists wanted to understand whether there might be a relationship between gut flora and depression.

As the researchers hypothesized, they did find distinct differences in the gut bacterial populations of those with depression when they compared them with those who did not experience depression.

These differences remained significant even after they had adjusted the data to account for antidepressant medication, which might also influence gut bacteria.

However, as the authors note, there is still the chance that factors other than depression might have driven the correlation. Before they firm up the links between gut bacteria and mental health, scientists will need to carry out much more work.

MNT published an in-depth article on how gut bacteria might influence the brain and behavior here.

3. Parkinson’s and the gut
Perhaps now that we have established a connection between the gut and the brain, we will find the thought of a gut link to Parkinson’s disease less surprising. MNT covered a study that looked at this theory in 2019.

Misfolded alpha-synuclein is the primary hallmark of Parkinson’s disease. These proteins aggregate and destroy certain dopamine producing cells in the brain, causing tremor and the other symptoms of the disease.

The study, in the journal Neuron, explains how the researchers created a model of Parkinson’s disease by injecting alpha-synuclein fibrils into muscles in the mice’s gut.

In the experiment, these clumps traveled from the gut to the brain through the vagus nerve. Within a few months, the mice developed symptoms that mirrored Parkinson’s in humans.

Following on from the findings above, some researchers have begun asking whether prebiotics might stave off Parkinson’s. A study using a roundworm model suggests that this theory might be worth pursuing.

Discoveries and mysteries
Of course, because the brain is complex, it still holds many secrets. Even some of the most common behaviors, as yet, defy a neuroscientific explanation. A good example is a humble yawn.

Yawning is part of the human experience, but no one knows quite why we do it.

4. A yawning chasm in our knowledge
Scientists have roundly dismissed conventional theories, such as a lack of oxygen in the brain. Why we do it, and what is happening in the brain is unclear. One of the particularly curious things about yawning is the fact that it is contagious.

A recent study investigating the contagious power of yawns appeared in the journal Current Biology. The authors believe that primitive reflexes in the primary motor cortex might trigger yawn contagion.

To investigate, the scientists used transcranial magnetic stimulation (TMS), which is a noninvasive technique employing magnetic fields to stimulate nerve cells. The researchers showed participants videos of people yawning and asked them to either resist the yawn or to let it out.

They found that when they increased levels of excitability in the motor cortex, they also increased participants’ urge to yawn.

As part of the experiment, the researchers measured levels of excitability in participants’ brains without TMS. They found that individuals with higher levels of cortical excitability and physiological inhibition in the primary motor cortex were more predisposed to yawn.

This finding adds evidence in support of one theory about yawning that involves the mirror-neuron system. This system, as the authors explain, “is thought to play a key role in action understanding, empathy, and the synchronization of group social behavior.”

So, we still do not fully understand yawning, but we are gathering evidence, and it might involve empathy.

5. New neurons in old age
Neurogenesis — or the creation of new neurons — is almost entirely complete by the time a newborn greets the world. Although new neurons may emerge in some parts of the brain during adulthood, for the majority of the brain, we have to make do with the neurons we get when we are born.

A study from 1998 claimed to have demonstrated that neurogenesis took place in the hippocampus, a region of the brain that is particularly important for memory. The findings were controversial, and later studies were contradictory.

Moving forward 2 decades, another team of scientists decided to settle the debate with the largest sample of brain tissue to date; they published these new findings in the journal Nature Medicine.

The team focused on a part of the hippocampus called the dentate gyrus. Incredibly, the researchers found that neurogenesis was occurring in all the samples of brain tissue, even in samples from individuals in their 90s.

The authors note that neurogenesis appears to slow as we age, but that it continues throughout our lives.

As with so many areas of neuroscience, however, researchers now need to gather more evidence as other studies have failed to replicate the findings.

6. A new type of brain cell
Even now, we are identifying new types of cells in the brain. A paper in Nature Neuroscience introduced one such newcomer to the neuroscientific lexicon: the rosehip neuron.

Rosehip neurons are inhibitory neurons, which are a class of cells that reduce the activity of other neurons. In the case of rosehip neurons, they apply the brakes to neurons in a way subtly different from other, similar cells.

In particular, rosehip neurons influence the activity of cortical pyramidal neurons, which account for around two-thirds of all neurons in the mammalian cerebral cortex.

Because scientists have not seen this cell in mice or other commonly used laboratory animals, the researchers believe it might help us understand why the human brain is so unique. However, at this stage, this is conjecture, and it is still not clear exactly what rosehip neurons do.

Of course, the studies this article discusses barely scratch the surface of neuroscience research today. Although we do not know what the future holds, we can guarantee it will be exciting.

It’s Brain Awareness Week, and to mark the occasion, we’re taking a look at research focused on the most complex organ in the human body. You can view all of our content for Brain Awareness.

Source: https://www.medicalnewstoday.com/articles/neuroscience-research-6-fascinating-findings#Discoveries-and-mysteries

Neurons that store abstract representations of past experiences are activated when a new, similar event takes place.

Imagine you are meeting a friend for dinner at a new restaurant. You may try dishes you haven’t had before, and your surroundings will be completely new to you. However, your brain knows that you have had similar experiences — perusing a menu, ordering appetizers, and splurging on dessert are all things that you have probably done when dining out.

MIT neuroscientists have now identified populations of cells that encode each of these distinctive segments of an overall experience. These chunks of memory, stored in the hippocampus, are activated whenever a similar type of experience takes place, and are distinct from the neural code that stores detailed memories of a specific location.

The researchers believe that this kind of “event code,” which they discovered in a study of mice, may help the brain interpret novel situations and learn new information by using the same cells to represent similar experiences.

“When you encounter something new, there are some really new and notable stimuli, but you already know quite a bit about that particular experience, because it’s a similar kind of experience to what you have already had before,” says Susumu Tonegawa, a professor of biology and neuroscience at the RIKEN-MIT Laboratory of Neural Circuit Genetics at MIT’s Picower Institute for Learning and Memory.

Tonegawa is the senior author of the study, which appears today in Nature Neuroscience. Chen Sun, an MIT graduate student, is the lead author of the paper. New York University graduate student Wannan Yang and Picower Institute technical associate Jared Martin are also authors of the paper.

Encoding abstraction

It is well-established that certain cells in the brain’s hippocampus are specialized to store memories of specific locations. Research in mice has shown that within the hippocampus, neurons called place cells fire when the animals are in a specific location, or even if they are dreaming about that location.

In the new study, the MIT team wanted to investigate whether the hippocampus also stores representations of more abstract elements of a memory. That is, instead of firing whenever you enter a particular restaurant, such cells might encode “dessert,” no matter where you’re eating it.

To test this hypothesis, the researchers measured activity in neurons of the CA1 region of the mouse hippocampus as the mice repeatedly ran a four-lap maze. At the end of every fourth lap, the mice were given a reward. As expected, the researchers found place cells that lit up when the mice reached certain points along the track. However, the researchers also found sets of cells that were active during one of the four laps, but not the others. About 30 percent of the neurons in CA1 appeared to be involved in creating this “event code.”

“This gave us the initial inkling that besides a code for space, cells in the hippocampus also care about this discrete chunk of experience called lap 1, or this discrete chunk of experience called lap 2, or lap 3, or lap 4,” Sun says.

To further explore this idea, the researchers trained mice to run a square maze on day 1 and then a circular maze on day 2, in which they also received a reward after every fourth lap. They found that the place cells changed their activity, reflecting the new environment. However, the same sets of lap-specific cells were activated during each of the four laps, regardless of the shape of the track. The lap-encoding cells’ activity also remained consistent when laps were randomly shortened or lengthened.

“Even in the new spatial locations, cells still maintain their coding for the lap number, suggesting that cells that were coding for a square lap 1 have now been transferred to code for a circular lap 1,” Sun says.

The researchers also showed that if they used optogenetics to inhibit sensory input from a part of the brain called the medial entorhinal cortex (MEC), lap-encoding did not occur. They are now investigating what kind of input the MEC region provides to help the hippocampus create memories consisting of chunks of an experience.

Two distinct codes

These findings suggest that, indeed, every time you eat dinner, similar memory cells are activated, no matter where or what you’re eating. The researchers theorize that the hippocampus contains “two mutually and independently manipulatable codes,” Sun says. One encodes continuous changes in location, time, and sensory input, while the other organizes an overall experience into smaller chunks that fit into known categories such as appetizer and dessert.

“We believe that both types of hippocampal codes are useful, and both are important,” Tonegawa says. “If we want to remember all the details of what happened in a specific experience, moment-to-moment changes that occurred, then the continuous monitoring is effective. But on the other hand, when we have a longer experience, if you put it into chunks, and remember the abstract order of the abstract chunks, that’s more effective than monitoring this long process of continuous changes.”

The new MIT results “significantly advance our knowledge about the function of the hippocampus,” says Gyorgy Buzsaki, a professor of neuroscience at New York University School of Medicine, who was not part of the research team.

“These findings are significant because they are telling us that the hippocampus does a lot more than just ‘representing’ space or integrating paths into a continuous long journey,” Buzsaki says. “From these remarkable results Tonegawa and colleagues conclude that they discovered an ‘event code,’ dedicated to organizing experience by events, and that this code is independent of spatial and time representations, that is, jobs also attributed to the hippocampus.”

Tonegawa and Sun believe that networks of cells that encode chunks of experiences may also be useful for a type of learning called transfer learning, which allows you to apply knowledge you already have to help you interpret new experiences or learn new things. Tonegawa’s lab is now working on trying to find cell populations that might encode these specific pieces of knowledge.

The research was funded by the RIKEN Center for Brain Science, the Howard Hughes Medical Institute, and the JPB Foundation.

Source: http://news.mit.edu/2020/neuroscience-memory-cells-interpret-new-0406

We know that neuroscience forms the groundwork for artificial neural networks and in other machine learning applications. Now, this fascinating field surrounding the structure and function of the nervous system and the human mind is playing an important role in improving these applications. Researchers have found out that psychoanalysis — the brainchild of Sigmund Freud — has the potential to bring a fresh face to neuroscience.

The Observable Overlap

If we compare neuroscience with psychoanalysis, certain aspects do match. To break it down, neuroscience deals with the connections or “dialogues” between the brain and the nervous system, while psychoanalysis deals with psychopathology through interactions between a patient and a psychoanalyst. Both fields intersect at the functional level. Instances like thoughts which stem from the nervous system, gaining knowledge through this as a consequence, perception with emotions, etc, share a mutual area when it comes to understanding these two fields.

The above view has garnered strong criticism among neuroscientists because there is no exact evidence establishing a relationship between the two. However, there is a slow uprising in the connection between psychoanalysis and neuroscience. In an article by science journalist Kat McGowan, she details how psychoanalysis could answer problems lingering in neuroscience.

Psychoanalysis has insightful, provocative theories about emotions, unconscious thoughts and the nature of the mind. Neurobiology has the ability to test these ideas with powerful tools and experimental rigour. Together, the two fields might finally answer the most elusive question of them all: How is it that dreams, fantasies, memories and feelings — the subjective self — emerge from a hunk of flesh?  

So, the brain structure is simply a hotbed of cognitive activities. Psychoanalysis specifically delves into this and can uncover more than what lies underneath the network of billions of neural connections.

Exploring The ‘Unconscious’

One of the key elements Freud’s psychoanalysis is the concept of the ‘unconscious state’. What started as a link to unearthing schizophrenia, is now the subject of many studies. In fact, most of them lean toward neuroscience rather than towards psychology, when it comes to deciphering this grey area.

The relationship between neural connections and psychological disorders can explain in detail about why the disorder prevails in the first place. By hinging on this fact, there could be a relation to discovering more on neurons, as these form the basis of subjects such as deep learning. As a matter of fact, one study that looked into the aspect of brain connectivity posits why neuroscience is following the path of psychoanalysis.

In recent years, there has been an increasing interest, in unconscious processes; neuroscientific studies have, in fact, tested subliminal perceptions, implicit cognition, emotion processing and interoceptive perceptions with empirical methods. Though many studies indicate that unconscious processes influence awareness, the cognitive view of the unconscious differs from the psychodynamic notion of the unconscious, which encompasses affect and motivation.

What the study brought out was how psychoanalysis and neuroscience can concur in their approach and lead to an improved scientific temperament.

The Key To Unraveling DL And ML

With psychoanalysis brought into neuroscience, it can answer the mystery behind areas such as machine learning or even deep learning. These areas extensively derive their working based on the human brain. To stress on this point, the key difference between these AI fields and psychoanalysis is the computational factor. While ML or DL is focusing on learning something new, it gradually will follow the footsteps of a computer. This ‘logical’ component misses the ‘biological’ component. Psychoanalysis is where it could help bridge this gap. After all, the essence of mind going into AI is the norm of ‘intelligence’.

As a matter of fact, challenges in these fields could be envisioned in a very different way if emotions and thoughts are brought into the picture. For example, a better model or algorithm could be designed as well as memory requirements are brought down drastically. We see enormous amounts of data going through ML/DL projects. The Freudian field may hold answers ML/DL in the future by evolving into something unknown or unexplored.

Source: https://www.analyticsindiamag.com/how-psychoanalysis-can-help-neuroscience-and-neural-networks/

The researchers used a new type of magnetic resonance imaging (MRI) to take brain scans of 16 high school players, ages 15 to 17, before and after a season of football. They found significant changes in the structure of the grey matter in the front and rear of the brain, where impacts are most likely to occur, as well as changes to structures deep inside the brain. All participants wore helmets, and none received head impacts severe enough to constitute a concussion.

The study, which is the cover story of the November issue of Neurobiology of Disease, is one of the first to look at how impact sports affect the brains of children at this critical age. This study was made available online in July 2018 ahead of final publication in print this month.

“It is becoming pretty clear that repetitive impacts to the head, even over a short period of time, can cause changes in the brain,” said study senior author Chunlei Liu, a professor of electrical engineering and computer sciences and a member of the Helen Wills Neuroscience Institute at UC Berkeley. “This is the period when the brain is still developing, when it is not mature yet, so there are many critical biological processes going on, and it is unknown how these changes that we observe can affect how the brain matures and develops.”

Concerning trends

One bonk to the head may be nothing to sweat over. But mounting evidence shows that repeated blows to the cranium—such as those racked up while playing sports like hockey or football, or through blast injuries in military combat—may lead to long-term cognitive decline and increased risk of neurological disorders, even when the blows do not cause concussion.

Over the past decade, researchers have found that an alarming number of retired soldiers and college and professional football players show signs of a newly identified neurodegenerative disease called chronic traumatic encephalopathy (CTE), which is characterized by a buildup of pathogenic tau protein in the brain. Though still not well understood, CTE is believed to cause mood disorders, cognitive decline and eventually motor impairment as a patient ages. Definitive diagnosis of CTE can only be made by examining the brain for tau protein during an autopsy.

These findings have raised concern over whether repeated hits to the head can cause brain damage in youth or high school players, and whether it is possible to detect these changes at an early age.

“There is a lot of emerging evidence that just playing impact sports actually changes the brain, and you can see these changes at the molecular level in the accumulations of different pathogenic proteins associated with neurodegenerative diseases like Parkinson’s and dementia,” Liu said. “We wanted to know when this actually happens—how early does this occur?”

A matter of grey and white

The brain is built of white matter, long neural wires that pass messages back and forth between different brain regions, and grey matter, tight nets of neurons that give the brain its characteristic wrinkles. Recent MRI studies have shown that playing a season or two of high school football can weaken white matter, which is mostly found nestled in the interior of the brain. Liu and his team wanted to know if repetitive blows to the head could also affect the brain’s gray matter.

“Grey matter in the cortex area is located on the outside of the brain, so we would expect this area to be more directly connected to the impact itself,” Liu said.

The researchers used a new type of MRI called diffusion kurtosis imaging to examine the intricate neural tangles that make up gray matter. They found that the organization of the gray matter in players’ brains changed after a season of football, and these changes correlated with the number and position of head impacts measured by accelerometers mounted inside players’ helmets.

The changes were concentrated in the front and rear of the cerebral cortex, which is responsible for higher-order functions like memory, attention and cognition, and in the centrally located thalamus and putamen, which relay sensory information and coordinate movement.

“Although our study did not look into the consequences of the observed changes, there is emerging evidence suggesting that such changes would be harmful over the long term,” Liu said.

Tests revealed that students’ cognitive function did not change over the course of the season, and it is yet unclear whether these changes in the brain are permanent, the researchers say.

“The brain microstructure of younger players is still rapidly developing, and that may counteract the alterations caused by repetitive head impacts,” said first author Nan-Ji Gong, a postdoctoral researcher in the Department of Electrical Engineering and Computer Sciences at UC Berkeley.

However, the researchers still urge caution—and frequent cognitive and brain monitoring—for youth and high schoolers engaged in impact sports.

“I think it would be reasonable to debate at what age it would be most critical for the brain to endure these sorts of consequences, especially given the popularity of youth football and other sports that cause impact to the brain,” Liu said.

Source: https://medicalxpress.com/news/2018-11-high-school-football-teenage-brain.html