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auditory

Scientists Are Figuring Out Why Some People Can ‘Hear’ The Voices of The Dead

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Scientists have identified the traits that may make a person more likely to claim they hear the voices of the dead.

According to new research, a predisposition to high levels of absorption in tasks, unusual auditory experiences in childhood, and a high susceptibility to auditory hallucinations all occur more strongly in self-described clairaudient mediums than the general population.

 

The finding could help us to better understand the upsetting auditory hallucinations that accompany mental illnesses such as schizophrenia, the researchers say.

The Spiritualist experiences of clairvoyance and clairaudience – the experience of seeing or hearing something in the absence of an external stimulus, and attributed to the spirits of the dead – is of great scientific interest, both for anthropologists studying religious and spiritual experiences, and scientists studying pathological hallucinatory experiences.

In particular, researchers would like to better understand why some people with auditory experiences report a Spiritualist experience, while others find them more distressing, and receive a mental health diagnosis.

“Spiritualists tend to report unusual auditory experiences which are positive, start early in life and which they are often then able to control,” explained psychologist Peter Moseley of Northumbria University in the UK.

“Understanding how these develop is important because it could help us understand more about distressing or non-controllable experiences of hearing voices too.”

He and his colleague psychologist Adam Powell of Durham University in the UK recruited and surveyed 65 clairaudient mediums from the UK’s Spiritualists’ National Union, and 143 members of the general population recruited through social media, to determine what differentiated Spiritualists from the general public, who don’t (usually) report hearing the voices of the dead.

 

Overall, 44.6 percent of the Spiritualists reported hearing voices daily, and 79 percent said the experiences were part of their daily lives. And while most reported hearing the voices inside their head, 31.7 percent reported that the voices were external, too.

The results of the survey were striking.

Compared to the general population, the Spiritualists reported much higher belief in the paranormal, and were less likely to care what other people thought of them.

The Spiritualists on the whole had their first auditory experience young, at an average age of 21.7 years, and reported a high level of absorption. That’s a term that describes total immersion in mental tasks and activities or altered states, and how effective the individual is at tuning out the world around them.

In addition, they reported that they were more prone to hallucination-like experiences. The researchers noted that they hadn’t usually heard of Spiritualism prior to their experiences; rather, they had come across it while looking for answers.

In the general population, high levels of absorption were also strongly correlated with belief in the paranormal – but little or no susceptibility to auditory hallucinations. And in both groups, there were no differences in the levels of belief in the paranormal and susceptibility to visual hallucinations.

 

These results, the researchers say, suggest that experiencing the ‘voices of the dead’ is therefore unlikely to be a result of peer pressure, a positive social context, or suggestibility due to belief in the paranormal. Instead, these individuals adopt Spiritualism because it aligns with their experience and is personally meaningful to them.

“Our findings say a lot about ‘learning and yearning’. For our participants, the tenets of Spiritualism seem to make sense of both extraordinary childhood experiences as well as the frequent auditory phenomena they experience as practising mediums,” Powell said.

“But all of those experiences may result more from having certain tendencies or early abilities than from simply believing in the possibility of contacting the dead if one tries hard enough.”

Future research, they concluded, should explore a variety of cultural context to better understand the relationship between absorption, belief, and the strange, spiritual experience of ghosts whispering in one’s ear.

The research has been published in Mental Health, Religion and Culture.

 



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Finally, Scientists Have Developed an Objective Way to Measure Tinnitus

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Some experiences in life are hard to describe, but that doesn’t make them any less real. Around the world up to 20 percent of people experience a chronic phantom ringing or buzzing in their ears, known as tinnitus.

 

The sounds – often high-pitched – are not connected to any known acoustic stimuli, and today, diagnosis depends solely on subjective experiences relayed by patients. Now, scientists in Australia think they have devised a method to ‘see’ the perception of tinnitus in the brain.

It could be the first objective clinical tool for measuring someone’s tinnitus, and a step towards finding ways to treat this widespread and incurable condition.

In recent years, brain imaging studies in both animals and humans have shown tinnitus is linked to an increase in neural firing as well as changes in connectivity within certain brain regions. Still, it’s only with the advent of new technology that we’ve come closer to a proper assessment based on this relationship.

Functional near-infrared spectroscopy (fNIRS) is a non-invasive, portable and virtually silent instrument that allows scientists to measure brain blood flow activity related to sound better than ever before.

In 2014, fNIRS was used for the first time to measure tinnitus perceptions in the brain, and the results revealed increased blood flow activity in the right auditory cortex. Further clinical research using this technology showed increased activity not just in the auditory cortex but also in nearby non-auditory regions, such as the frontal cortex and some visual processing areas.

 

Recently, the technology has even been used to show improved tinnitus symptoms after transcranial direct current stimulation, a potential new treatment in the works.

In 2018, scientists in Australia showed that fNIRS signals in the auditory cortex reflected both the presence and intensity of phantom sounds, indicating a valid way to measure the severity of tinnitus.

Now, an update from the same team has recorded fNIRS signals and used machine learning algorithms to classify 25 individuals with tinnitus based on the severity of their condition.

Compared to 21 healthy controls, patients with chronic ringing or buzzing in their ears showed significantly higher connectivity between temporal, frontal and occipital regions of the brain at rest.

That was enough for the machine learning algorithm to objectively measure tinnitus with an accuracy of 78 percent, according to probability analysis. What’s more, the algorithm was able to differentiate between severities of tinnitus with an accuracy of 87 percent.

Similar to previous research, the imaging showed higher connectivity in the temporal-frontal lobe, which is attributed to tinnitus duration and stress, and higher connectivity in the temporal-occipital lobe, which is somehow connected to the intensity of the sound.

 

This suggests both the loudness and annoyance of tinnitus can be measured separately in the brain. It also supports preliminary research which shows the perceived loudness of tinnitus can be reduced by making the brain process multiple forms of sensory information.

When subject to auditory and visual patterns in the current study, those with tinnitus actually showed reduced brain activity.

The authors think this might be due to a suppression of neural activity from too much perceived stimuli, or a ‘blood stealing’ effect, where increased blood flow is sent to activated cortical regions at the expense of other adjacent regions.

“Our findings show the feasibility of using fNIRS and machine learning to develop an objective measure of tinnitus,” the authors conclude.

“Such a measure would greatly benefit clinicians and patients by providing a tool to objectively assess new treatments and patients’ treatment progress.”

Tinnitus currently has no known cause or cure, and while there are some excellent tools that can be used to manage symptoms in some, options are limited and we really need more research to help people cope with this condition.

 

Among those with severe tinnitus, rates of depression and anxiety are unusually high, and the loudness of phantom noises is one of the biggest complaints.

An objective measurement may not change the reality for many patients today, but it could help those in the future get help sooner.

Plus, if we can use these aberrant brain changes to better understand the underlying mechanism behind tinnitus, we might be able to find a better way to treat it in the future.

It’s not clear, for instance, why tinnitus is linked to asymmetric brain activity, although it could have to do with which sides of the body the sounds are perceived from. 

It also must be noted that while the authors claim this to be an ‘objective’ clinical measurement, subjective ratings of tinnitus still had to be used to split patients into groups and compare their brain activity to perceived severity.

“Tinnitus by nature will always have a subjective component” the authors admit, but they say the current measure is the most objective we’ve got.

The study was published in PLOS One.

 



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Controversial Discovery Says Origins of Human Language Existed 25 Million Years Ago

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A structure critical to our brain’s core language pathway, found only in humans and apes, has now also been identified in monkeys, according to a controversial new study – suggesting the origins of language may have appeared 20 to 25 million years earlier than previously thought.

 

Compared to other animals, the human brain is uniquely adapted to language. Our ability to produce speech, listen, and communicate with one another is unparalleled, and to understand why, we need to know how we got here.

Unfortunately, brain tissue doesn’t survive over evolutionary timescales, so it’s hard to know when the first building blocks for language appeared in our distant past. Today, if we want to locate this missing brain ‘fossil’, scientists must largely rely on our living cousins.

So far, brain imaging studies in chimpanzees have revealed a similar language circuit to humans, but the idea that monkeys may also contain something comparable remains highly disputed.

Now, some researchers claim that’s because we’ve been looking in the wrong spot. While neuroscientists have been focused on the prefrontal cortex and the temporal lobes – where this pathway exists in humans and apes – the origins of our language may actually lie in the auditory cortex of rhesus macaques. 

“I admit we were astounded to see a similar pathway hiding in plain sight within the auditory system of nonhuman primates,” says comparative neuropsychologist Chris Petkov from Newcastle University in the UK.

 

“It is like finding a new fossil of a long lost ancestor.”

If the researchers are right, and they’ve truly found this missing link, the first neural building blocks for the evolution of language may have appeared much earlier than we thought.

The last common ancestor to macaques and humans lived roughly 25-30 million years ago, and that’s way earlier than the ancestor we share with chimps, which lived only 5 million years ago.

In humans, speech is generally produced and perceived along a core language pathway, known as the arcuate fasciculus (AF), which spans the prefrontal cortex and the temporal lobe.

Over the years, however, we’ve come to realise this circuit is far more complex than we once thought. It’s connected to many other regions of the brain, and some research suggests the auditory cortex plays a key part.

Comparing the brains of humans, apes, and monkeys alongside new imaging data, the new study was able to identify the AF in the auditory complex of both halves of the human brain, and determine it was more developed on the left side than the right.

 

They then showed a similar (if less pronounced) pathway existed in the same areas in both macaque and chimp brains.

Noting how the connection evolved differently in humans, the authors argue our system for language seems to have moved away from relying so heavily on the auditory pathway, involving more temporal and parietal areas of the brain.

“To be honest, we were really quite surprised that the auditory system has this privileged pathway to vocal production regions in frontal cortex,” Petkov told Newsweek.

“That in itself tells us that there is something special about this pathway. The link to projection from the auditory system to frontal cortex regions, which in humans supports language, is fascinating. So we were honestly surprised to find it there and see that both apes and monkeys have their own version of this pathway.”

The observations certainly fit with the idea that language adaptations may have arisen from primate auditory pathways, which the authors say involve spatial processing, as well as sound and vocal patterning.

While human language is wholly unique, the results suggest we aren’t the only ones with sophisticated levels of auditory cognitions and vocal communication.

 

Macaques are known to communicate about food, identity, or danger with various vocalisations, and perhaps it’s this auditory connection that allows them to do that, at least in part.

“This discovery has tremendous potential for understanding which aspects of human auditory cognition and language can be studied with animal models in ways not possible with humans and apes,” says neurologist Timothy Griffiths at Newcastle University.

Such knowledge would also be huge for treating human patients with neurological issues. Language can be spoken, written or signed, so even if a stroke patient can no longer communicate via one of these ways, perhaps they have other intact language pathways that can still be accessed.

It’s an exciting premise, but there’s still a lot that needs to be verified. Brain imaging studies can’t tell us everything we need to know, and further research will need to explore this auditory pathway in greater detail.

Even Petkov himself admitted to Inverse that this missing brain fossil is “highly controversial”. But given how much good it could do, he thinks it’s “important to resolve.”

The authors suggest further imaging studies be done on the brains of other monkeys to see how far back in time they can trace this missing link.

The study was published in Nature Neuroscience.

 



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Cuban ‘Sonic Attack’ Survivors Have Structural Changes in Their Brains, Study Finds

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Starting in late 2016, a number of US government personnel stationed in Havana, Cuba started reporting something strange: they heard intensely loud sounds emanating from a single direction.

 

The source of those sounds is still a complete mystery to this day. Even stranger: the strange sounds seemed to make the staffers physically ill – with reported symptoms ranging from hearing loss and dizziness to intense headaches.

A new analysis published Tuesday in the journal JAMA found that the incident – often labelled as the “Cuban sonic attack” by the media – may have caused alterations in the victims’ brains.

The team of researchers found differing “neuroimaging findings” between control groups and those who were exposed to the attacks by examining brain scans using three different types of imaging techniques.

The findings include “significant differences” in white matter volumes among many patients, as well as lower functional connectivity in the auditory and visual parts of the brain.

The team, led by Ragini Verma, a PhD candidate at the Department of Radiology at the University of Pennsylvania, did note that the results have to be taken with a grain of salt and that the relevance of the differences “may require further study”.

One major caveat: the team did not have access to brain scans prior to being exposed to the phenomena as a point of comparison.

 

According to the BBC, the study was immediately panned by Cuban scientists. Cuban lead scientist Mitchell Valdés-Sosa told the BBC that “the changes in the brain images are very small, very diverse and very diffuse… They do not correspond to a coherent explanation.”

Scientists have been trying to figure out what’s behind “Havana syndrome” ever since the first reports started surfacing in August 2017.

According to a separate 2018 study, the diplomats experienced “moderate to severe sensorineural hearing loss” and “persistent sleep dysfunction” as a result of being exposed to “auditory and sensory phenomena.”

Yet no smoking gun was ever found. A media frenzy of conspiracy theories followed, with some theorizing that the event involved the use of a sonic or microwave weapon.

The Associated Press even obtained a recording of strange sounds the personnel were hearing, but it never ended up helping the investigation.

The embassy in Havana was only reopened in August 2015 after being shut for over 50 years – a major turning point in the relationship between the two countries.

But while the US has yet to publicly voice its own theory as to what went down, Cuba-US relations have taken a hit as a result of the alleged attacks.

This article was originally published by Futurism. Read the original article.

 



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New Brain Study Finally Explains Why Blind People’s Hearing Works So Precisely

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Not everybody hears the same. Numerous studies have shown people who become blind early in life can experience enhanced auditory powers compared to sighted people, but a new experiment appears to have revealed the neural basis of this phenomenon for the first time.

 

The common assumption that people without sight have superior hearing isn’t just an assumption; it’s borne out by a body of research demonstrating just that, in addition to other advantages the condition appears to confer.

But while scientists have known for a long time that people with early onset blindness have more nuanced or accurate hearing, the brain mechanisms that enable this remain far from understood.

“There’s this idea that blind people are good at auditory tasks, because they have to make their way in the world without visual information,” says neuroscientist Ione Fine from the University of Washington.

“We wanted to explore how this happens in the brain.”

To that end, Fine and her team used functional magnetic resonance (fMRI) imaging to examine activity in the auditory cortex – the part of the brain that processes auditory information – in both blind people and a control group of sighted people.

In their cohort, four of the blind participants had early onset blindness, and five had the condition anophthalmia, in which the eyes fail to develop.

In the experiment, these participants were played a number of pure tones resonating at different frequencies, while an fMRI device recorded their brain activity. A control group went through the same procedure.

 

When the researchers analysed the results, they found that the blind people in the experiment tended to process the tones in a narrower, more accurate bandwidth than sighted individuals, suggesting their sense of frequency tuning in the auditory cortex was better refined than the non-blind group.

“Our study shows that the brains of blind individuals are better able to represent frequencies,” one of the team, psychology graduate student Kelly Chang, explains.

“For a sighted person, having an accurate representation of sound isn’t as important because they have sight to help them recognise objects, while blind individuals only have auditory information.

This gives us an idea of what changes in the brain explain why blind people are better at picking out and identifying sounds in the environment.”

017 mri study confirms blind hearing 1(Kelly Chang/UW)

Left: red colours show brain regions responding more to to low-pitched tones, while blue-colour areas responded more to high-pitched tones. Right: overall, frequency tuning in blind participants was narrower than in sighted people.

It’s worth noting we’re only dealing with a small group of participants here, which we always need to bear in mind when considering the findings of studies.

 

But the team nonetheless suggests their results amount to the first evidence for systematic changes in neural tuning within the human auditory cortex as a result of blindness.

How the auditory cortex develops this form of neuroplasticity remains unknown, but in their paper, the team speculates it could be “a developmental adaptation to early blindness, the ongoing effects of visual deprivation, and/or differential auditory demands that result from being blind”.

Future studies could help us get closer to understanding the basis of the brain’s auditory adaptations observed here in greater detail, but for now at least, researchers have a new target to examine, even if there’s still a lot left for us to learn.

“In blind individuals, more information needs to be extracted from sound – and this region seems to develop enhanced capacities as a result,” Fine says.

“This provides an elegant example of how the development of abilities within infant brains is influenced by the environment they grow up in.”

The findings are reported in The Journal of Neuroscience.

 



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