Brain, emotion, sight and sound processing, concussion and Parkinson

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DID HANS ASPERGER ACTIVELY ASSIST THE NAZI EUTHANASIA PROGRAM?

Researchers have investigated Hans Asperger’s Nazi era publications and have revealed he actively cooperated with the Nazi’s euthanasia program. The Kinder-Euthanasie (child euthanasia) program resulted in the murder of thousands of physically and mentally disabled children under Nazi rule. READ MORE…

LONG TERM CAFFEINE USE WORSENS ALZHEIMER’S SYMPTOMS

Dopamine may have given humans our social edge over other apes

chimps

Male chimpanzees signal their aggression when they display their big canines, in contrast with humans, who show small canines when they smile.

Sergey Uryadnikov/shutterstock.com

Dopamine may have given humans our social edge over other apes

Humans are the ultimate social animals, with the ability to bond with mates, communicate through language, and make small talk with strangers on a packed bus. (Put chimpanzees in the same situation and most wouldn’t make it off the bus alive.) A new study suggests that the evolution of our unique social intelligence may have initially begun as a simple matter of brain chemistry.

Neuroanatomists have been trying for decades to find major differences between the brains of humans and other primates, aside from the obvious brain size. The human brain must have reorganized its chemistry and wiring as early human ancestors began to walk upright, use tools, and develop more complex social networks 6 million to 2 million years ago—well before the brain began to enlarge 1.8 million years ago, according to a hypothesis proposed in the 1960s by physical anthropologist Ralph Holloway of Columbia University. But neurotransmitters aren’t preserved in ancient skulls, so how to spot those changes?

One way is to search for key differences in neurochemistry between humans and other primates living today. Mary Ann Raghanti, a biological anthropologist at Kent State University in Ohio, and colleagues got tissue samples from brain banks and zoos of 38 individuals from six species who had died of natural causes: humans, tufted capuchins, pig-tailed macaques, olive baboons, gorillas, and chimpanzees. They sliced sections of basal ganglia—clusters of nerve cells and fibers in a region at the base of the brain known as the striatum, which is a sort of clearinghouse that relays signals from different parts of the brain for movement, learning, and social behavior. They stained these slices with chemicals that react to different types of neurotransmitters, including dopamine, serotonin, and neuropeptide Y—which are associated with sensitivity to social cues and cooperative behavior. Then, they analyzed the slices to measure different levels of neurotransmitters that had been released when the primates were alive.

Compared with other primates, both humans and great apes had elevated levels of serotonin and neuropeptide Y, in the basal ganglia. However, in line with another recent study on gene expression, humans had dramatically more dopamine in their striatum than apes, they report today in the Proceedings of the National Academy of Sciences. Humans also had less acetylcholine, a neurochemical linked to dominant and territorial behavior, than gorillas or chimpanzees. The combination “is a key difference that sets apart humans from all other species,” Raghanti says.

Those differences in neurochemistry may have set in motion other evolutionary changes, such as the development of monogamy and language in humans, theorizes Kent State paleoanthropologist Owen Lovejoy, a co-author. He proposes a new “neurochemical hypothesis for the origin of hominids,” in which females mated more with males who were outgoing, but not too aggressive. And males who cooperated well with other males may have been more successful hunters and scavengers. As human ancestors got better at cooperating, they shared the know-how for making tools and eventually developed language—all in a feedback loop fueled by surging levels of dopamine. “Cooperation is addictive,” Raghanti says.

Lovejoy thinks these neurochemical changes were already in place more than 4.4 million years ago, when Ardipithecus ramidus, an early member of the human family, lived in Ethiopia. Compared with chimpanzees, which display large canines when they bare their teeth in aggressive displays, A. ramidus males had reduced canines. That meant that when they smiled—like male humans today—they were likely signaling cooperation, Lovejoy says.

However, it’s a big leap to prove that higher levels of dopamine changed the evolution of human social behavior. The neurochemistry of the brain is so complex, and dopamine is involved in so many functions that it’s hard to know precisely why natural selection favored higher dopamine levels—or even whether it was a side effect of some other adaptation, says evolutionary geneticist Wolfgang Enard at Ludwig Maximilian University of Munich in Germany. But he says this painstaking research to quantify differences in neurochemistry among primates is important, especially as researchers study differences in gene expression in the brain. Raghanti agrees and is now writing a grant to study the brain tissue of bonobos.

Music and Movies Play With Our Minds By Bending Time

Music and Movies Play With Our Minds By Bending Time

Summary: Emotional processing may be linked to perception of time, especially in music and movies, a new study reports.

Source: Horizon.

Movie directors regularly manipulate the passage of time in films to entertain their audiences, but researchers are trying to unravel the effect this can have on our brains.

Little is known about how the human brain processes time or how slow motion, time lapse and even music can alter our perception of how quickly it passes, changing our emotions and cognitive abilities.

Professor Clemens Wöllner, a cognitive musicology researcher at the University of Hamburg in Germany, describes an iconic scene in the 1990s blockbuster film Forrest Gump as an example.

As the kind-hearted but hapless hero, then a child, is being chased by bullies on bikes, he runs jerkily before picking up speed and the leg braces that constrain him pop off.

‘It’s a very emotional scene — and of course it’s in slow motion,’ said Prof. Wöllner, who is the principal investigator on an EU-funded project called SloMo.

By using slow motion, usually in combination with emotionally charged music, movie directors intuitively tap into how our perception of time affects our cognition, according to Prof. Wöllner.

The way the mind perceives time is something that researchers are only beginning to study at a fundamental level, though one day the findings from such work could feed into other research on human diseases and wellbeing.

The SloMo project is aiming to explore the theory that emotional processing by the mind is linked to the perception of time.

‘The theory is that during highly emotional moments we are highly susceptible to information and take in more information,’ said Prof. Wöllner. ‘Our brain is more alert and so we have the feeling that time passes more slowly.’

The team is examining the use of slow motion in music, dance, performing arts and audiovisual media like film or sports footage.

The project, which started in April and is funded for five years through the EU’s European Research Council (ERC), comprises six main studies and an initial total of 15 experiments.

Initial findings

The researchers have already presented initial findings at the European Society for the Cognitive Sciences of Music Conference, which was held at Ghent University, Belgium, during the summer. The team showed healthy volunteers slow-motion scenes taken from movies, dance and sports footage, recording their emotional, physiological and eye-movement responses. They then recorded the same parameters in the viewers while speeding up the footage to a real-life pace.

The iconic Forrest Gump scene was one of the pieces shown. Prof. Wöllner said two key emotional dimensions, which psychologists call arousal and valence, were markedly different when people watched the original slow-motion version compared with the normal-speed version.

Arousal refers to the emotional state connected to alertness and internal activity, including physiological parameters like heart rate, while valence refers to the value of an emotion, often either as positive for feelings like happiness, or negative for feelings like anger or fear.

When subjects were shown the Forrest Gump scene in real time, their arousal state was higher, while valence was higher in the slow-motion version when music was played. The team also found that people’s eye movements differed.

‘In slow motion, the gaze behaviour of the eye was more dispersed,’ said Prof. Wöllner. ‘They looked at other things (in the scene).’ He added that in real time, viewers tended to focus more, although not exclusively, on the main character.

In other words, slow motion enabled viewers to perceive details they otherwise wouldn’t have noticed.

But other experiments within the project are also probing how music can be used to influence our perception of motion and time. Music compositions are often multi-layered with different levels of structure in both the melody and rhythm, to which listeners can synchronise.

In one experiment, the researchers are manipulating musical excerpts with different structural levels and will examine the volunteers’ judgements of duration, along with physical responses like the speed the participants tapped their fingers to the perceived pulse of the music.

From a learning point of view, slow speed is important in music practice and dance rehearsal, so the project may have implications for education. The theory is that, in slowing down, the brain’s cognitive load — or mental capacity — is reduced, making it easier to concentrate on new notes or information.

Prof. Wöllner said the project will also examine ‘time dilation’ — a phenomenon that music can also be used to alter. The idea is that repetition makes time appear to speed up, which is why time seems to go faster as we age, or why the first time we travel to a new place the journey seems long but the return leg seems faster.

Repetition is central to most musical genres and affects listeners’ expectations. Prof. Wöllner says it is possible to alter some of the musical features and study how this affects people’s perceptions of duration and behavioural responses to music.

He believes this ability to use music to change people’s perception of time could also bring benefits to their wellbeing, although he stresses that SloMo is focusing on fundamental, basic research.

Image shows a tennis ball bouncing.

‘One field certainly is how music may help in diseases with a very strong temporal component, for instance Parkinson’s,’ he said.

Mapping time

But it may be important to answer some of the basic questions about how the brain is able to encode time before looking at how this can be applied to helping treat diseases.

The EU-funded Brain in Time (BiT) project, is looking at how our brains map duration. A lot of research in recent years has focused on where in the brain time is encoded, says Professor Domenica Bueti, principal investigator on the project and head of the time perception lab at the International School for Advanced Studies (SISSA) in Trieste, Italy.

‘What I proposed is, to go from “where” to “how” and “when”,’ she said. ‘How do brain regions encode time? What are the connections between these regions? How do they talk?’

Her project aims to test the hypothesis that there is a topography or map of time within the brain, something she refers to as a ‘chronotopy’. It will look at how the brain encodes time in the short term, at split-second level.

Prof. Bueti believes they will find that specific groups of brain cells respond selectively with different millisecond time durations.

She and her colleagues will use neuroimaging techniques, such as functional magnetic resonance imaging, to study the brains of healthy volunteers as they perform different tasks.

The team will also use a technique called transcranial magnetic stimulation to create virtual lesions within the brain while subjects are performing tasks. This can temporarily interfere with signals in the brain, allowing the researchers to study what different parts involved in time cognition do.

The project started in October 2016 with a five-year grant from the ERC.

Prof. Bueti hopes that chronomaps could provide a neurological signature of whether the brain’s time cognition system is working properly or not. This could be used to help people with conditions that have time perception problems.

People with damage to specific brain regions like the basal ganglia or cerebellum, or those with certain degenerative diseases like Parkinson’s can experience difficulties in judging time on the short scale. Understanding how the brain deals with time cognition could help develop new diagnostic tools for temporal deficiencies like these.

‘Time is so abstract,’ said Prof. Bueti. ‘Yet, it’s a fundamental dimension of everything.’

ABOUT THIS NEUROSCIENCE RESEARCH ARTICLE

Source: Horizon
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com images is credited to Josh Calabrese.

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Horizon “Music and Movies Play With Our Minds By Bending Time.” NeuroscienceNews. NeuroscienceNews, 24 October 2017.
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Connie’s comments: I play the TV station JAZZTV in absence of other musical instruments in the house and it helped my Alzheimer’s patient’s mood.  All caregivers are trained to massage, dance and sing with the senior clients.
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How We Recall the Past

How We Recall the Past

Summary: Researchers have identified a neural circuit that is critical for memory retrieval.

Source: MIT.

Neuroscientists discover a brain circuit dedicated to retrieving memories.

When we have a new experience, the memory of that event is stored in a neural circuit that connects several parts of the hippocampus and other brain structures. Each cluster of neurons may store different aspects of the memory, such as the location where the event occurred or the emotions associated with it.

Neuroscientists who study memory have long believed that when we recall these memories, our brains turn on the same hippocampal circuit that was activated when the memory was originally formed. However, MIT neuroscientists have now shown, for the first time, that recalling a memory requires a “detour” circuit that branches off from the original memory circuit.

“This study addresses one of the most fundamental questions in brain research — namely how episodic memories are formed and retrieved — and provides evidence for an unexpected answer: differential circuits for retrieval and formation,” says Susumu Tonegawa, the Picower Professor of Biology and Neuroscience, the director of the RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, and the study’s senior author.

This distinct recall circuit has never been seen before in a vertebrate animal, although a study published last year found a similar recall circuit in the worm Caenorhabditis elegans.

Dheeraj Roy, a recent MIT PhD recipient, and research scientist Takashi Kitamura are the lead authors of the paper, which appears in the Aug. 17 online edition of Cell. Other MIT authors are postdocs Teruhiro Okuyama and Sachie Ogawa, and graduate student Chen Sun. Yuichi Obata and Atsushi Yoshiki of the RIKEN Brain Science Institute are also authors of the paper.

Parts unknown

The hippocampus is divided into several regions with different memory-related functions — most of which have been well-explored, but a small area called the subiculum has been little-studied. Tonegawa’s lab set out to investigate this region using mice that were genetically engineered so that their subiculum neurons could be turned on or off using light.

The researchers used this approach to control memory cells during a fear-conditioning event — that is, a mild electric shock delivered when the mouse is in a particular chamber.

Previous research has shown that encoding these memories involves cells in a part of the hippocampus called CA1, which then relays information to another brain structure called the entorhinal cortex. In each location, small subsets of neurons are activated, forming memory traces known as engrams.

“It’s been thought that the circuits which are involved in forming engrams are the same as the circuits involved in the re-activation of these cells that occurs during the recall process,” Tonegawa says.

However, scientists had previously identified anatomical connections that detour from CA1 through the subiculum, which then connects to the entorhinal cortex. The function of this circuit, and of the subiculum in general, was unknown.

In one group of mice, the MIT team inhibited neurons of the subiculum as the mice underwent fear conditioning, which had no effect on their ability to later recall the experience. However, in another group, they inhibited subiculum neurons after fear conditioning had occurred, when the mice were placed back in the original chamber. These mice did not show the usual fear response, demonstrating that their ability to recall the memory was impaired.

This provides evidence that the detour circuit involving the subiculum is necessary for memory recall but not for memory formation. Other experiments revealed that the direct circuit from CA1 to the entorhinal cortex is not necessary for memory recall, but is required for memory formation.

“Initially, we did not expect the outcome would come out this way,” Tonegawa says. “We just planned to explore what the function of the subiculum could be.”

“This paper is a tour de force of advanced neuroscience techniques, with an intriguing core result showing the existence and importance of different pathways for formation and retrieval of hippocampus-dependent memories,” says Karl Deisseroth, a professor of bioengineering and psychiatry and behavioral sciences at Stanford University, who was not involved in the study.

Editing memories

Why would the hippocampus need two distinct circuits for memory formation and recall? The researchers found evidence for two possible explanations. One is that interactions of the two circuits make it easier to edit or update memories. As the recall circuit is activated, simultaneous activation of the memory formation circuit allows new information to be added.

Image shows CA1 hippocampal neurons.

“We think that having these circuits in parallel helps the animal first recall the memory, and when needed, encode new information,” Roy says. “It’s very common when you remember a previous experience, if there’s something new to add, to incorporate the new information into the existing memory.”

Another possible function of the detour circuit is to help stimulate longer-term stress responses. The researchers found that the subiculum connects to a pair of structures in the hypothalamus known as the mammillary bodies, which stimulates the release of stress hormones called corticosteroids. That takes place at least an hour after the fearful memory is recalled.

While the researchers identified the two-circuit system in experiments involving memories with an emotional component (both positive and negative), the system is likely involved in any kind of episodic memory, the researchers say.

The findings also suggest an intriguing possibility related to Alzheimer’s disease, according to the researchers. Last year, Roy and others in Tonegawa’s lab found that mice with a version of early-stage Alzheimer’s disease have trouble recalling memories but are still able to form new memories. The new study suggests that this subiculum circuit may be affected in Alzheimer’s disease, although the researchers have not studied this.

ABOUT THIS NEUROSCIENCE RESEARCH ARTICLE

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

Source: Anne Trafton – MIT
Image Source: NeuroscienceNews.com image is credited to Dheeraj Roy/Tonegawa Lab, MIT.
Original Research: Abstract for “Distinct Neural Circuits for the Formation and Retrieval of Episodic Memories” by Dheeraj S. Roy, Takashi Kitamura, Teruhiro Okuyama, Sachie K. Ogawa, Chen Sun, Yuichi Obata, Atsushi Yoshiki, and Susumu Tonegawa in Cell. Published online August 17 2017 doi:10.1016/j.cell.2017.07.013

MIT “How We Recall the Past.” NeuroscienceNews. NeuroscienceNews, 17 August 2017.
<http://neurosciencenews.com/memory-retrieval-neural-network-7321/&gt;.

Abstract

Distinct Neural Circuits for the Formation and Retrieval of Episodic Memories

Highlights

•dSub and the circuit, CA1→dSub→EC5, are required for hippocampal memory retrieval
•The direct CA1→EC5 circuit is essential for hippocampal memory formation
•The dSub→MB circuit regulates memory-retrieval-induced stress hormone responses
•The dSub→EC5 circuit contributes to context-dependent memory updating

Summary
The formation and retrieval of a memory is thought to be accomplished by activation and reactivation, respectively, of the memory-holding cells (engram cells) by a common set of neural circuits, but this hypothesis has not been established.

The medial temporal-lobe system is essential for the formation and retrieval of episodic memory for which individual hippocampal subfields and entorhinal cortex layers contribute by carrying out specific functions.

One subfield whose function is poorly known is the subiculum. Here, we show that dorsal subiculum and the circuit, CA1 to dorsal subiculum to medial entorhinal cortex layer 5, play a crucial role selectively in the retrieval of episodic memories. Conversely, the direct CA1 to medial entorhinal cortex layer 5 circuit is essential specifically for memory formation.

Our data suggest that the subiculum-containing detour loop is dedicated to meet the requirements associated with recall such as rapid memory updating and retrieval-driven instinctive fear responses.

“Distinct Neural Circuits for the Formation and Retrieval of Episodic Memories” by Dheeraj S. Roy, Takashi Kitamura, Teruhiro Okuyama, Sachie K. Ogawa, Chen Sun, Yuichi Obata, Atsushi Yoshiki, and Susumu Tonegawa in Cell. Published online August 17 2017 doi:10.1016/j.cell.2017.07.013

Very stressful events affect the brains of girls and boys in different ways

Very stressful events affect the brains of girls and boys in different ways, a Stanford University study suggests.

A part of the brain linked to emotions and empathy, called the insula, was found to be particularly small in girls who had suffered trauma.

But in traumatised boys, the insula was larger than usual.

This could explain why girls are more likely than boys to develop post-traumatic stress disorder (PTSD), the researchers said.

Their findings suggest that boys and girls could display contrasting symptoms after a particularly distressing or frightening event, and should be treated differently as a result.

The research team, from Stanford University School of Medicine, said girls who develop PTSD may actually be suffering from a faster than normal ageing of one part of the insula – an area of the brain which processes feelings and pain.

A cross-section map of the brainImage copyrightSCIENCE PHOTO LIBRARY
Image captionThe insula, also known as the insular cortex, is linked to the body’s experience of pain or emotional experiences of fear

The insula, or insular cortex, is a diverse and complex area, located deep within the brain which has many connections.

As well as processing emotions, it plays an important role in detecting cues from other parts of the body.

The researchers scanned the brains of 59 children aged nine to 17 for their study, published in Depression and Anxiety.

One group, of 14 girls and 16 boys, had suffered at least one episode of severe stress or trauma while a second group, of 15 girls and 14 boys, had not been exposed to any.

In the group of traumatised boys and girls, there was evidence that one area of the insula – the anterior circular sulcus – had changed in size and volume compared with the group with no trauma.

This shows that the insula is changed by exposure to acute or long-term stress and plays a key role in the development of PTSD, the researchers said.

Different reactions

Lead study author Dr Megan Klabunde said it was important to consider the different physical and emotional reactions to stressful events.

“It is important that people who work with traumatised youth consider the sex differences.

“Our findings suggest it is possible that boys and girls could exhibit different trauma symptoms and that they might benefit from different approaches to treatment.”

And she added: “There are some studies suggesting that high levels of stress could contribute to early puberty in girls.”

Dr Klabunde said they would now look at other regions of the brain connected to the insula to see if they could detect similar changes.


What is PTSD?

Post-traumatic stress disorder is the term used to described the psychological effects of being involved in a traumatic event, such as a major car accident, a natural disaster, bullying, abuse or violent crime.

Many young people who experience very distressing events recover without experiencing PTSD – but some people do develop it.

Symptoms can include:

  • Flashbacks and nightmares
  • Avoiding reliving the event
  • Anxiety, unable to relax
  • Problems sleeping
  • Problems eating

The charity Young Minds says it is normal to experience symptoms for a few weeks after a distressing event but if you are still having symptoms after a month, it is a good idea to talk to your GP who should offer you some therapy to deal with your thoughts and behaviour.


Insular Cortex

In each hemisphere of the mammalian brain the insular cortex (often called insula, or insular lobe) is a portion of the cerebral cortex folded deep within the lateral sulcus (the fissure separating the temporal lobe from the parietal and frontal lobes).

The insulae are believed to be involved in consciousness and play a role in diverse functions usually linked to emotion or the regulation of the body’s homeostasis. These functions include perception, motor control, self-awareness, cognitive functioning, and interpersonal experience. In relation to these, it is involved in psychopathology.

The insular cortex is divided into two parts: the larger anterior insula and the smaller posterior insula in which more than a dozen field areas have been identified. The cortical area overlying the insula toward the lateral surface of the brain is the operculum (meaning lid). The opercula are formed from parts of the enclosing frontal, temporal, and parietal lobes.


The insula is involved in interoceptive processing, emotion awareness, and attention to salient stimuli. Research suggests that these functions are specific—albeit overlapping—within insula subdivisions. Additional studies also imply that sexual dimorphism and different rates of development occur within these subdivisions in youth. The purpose of this study was to examine potential insula subdivision structure differences in youth with PTSD symptoms as compared to controls and test sex as a moderator of these differences.

Methods

Insula structure (volume, surface area, and thickness) was measured with structural magnetic resonance imaging (sMRI) and calculated using Freesurfer software. We compared insula structure across age- and sex-matched boys and girls with (30 with and 29 without) PTSD symptoms while also controlling for age and whole brain measurements.

Results

Differences were specific to the insula’s anterior circular sulcus. Within this subregion, boys with PTSD symptoms demonstrated larger volume and surface area than control boys, while girls with PTSD symptoms demonstrated smaller volume and surface area than control girls.

http://onlinelibrary.wiley.com/doi/10.1002/da.22577/full