̽��ֱ�� of Cambridge - senses

Study shows brain differences in interpreting physical signals in mental health disorders

sc604 — Tue, 22 Jun 2021 01:16:31 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, found that the part of the brain which interprets physical signals from the body behaves differently in people with a range of mental health disorders, suggesting that it could be a target for future treatments.

̽��ֱ��researchers studied ‘interoception’ – the ability to sense internal conditions in the body – and whether there were any common brain differences during this process in people with mental health disorders. They found that a region of the brain called the dorsal mid-insula showed different activity during interoception across a range of disorders, including depression, schizophrenia, eating disorders and anxiety disorders.

Many people with mental health disorders experience physical symptoms differently, whether that’s feeling uncomfortably full in anorexia, or feeling like you don’t have enough air in panic disorder.

̽��ֱ��results, reported in ̽��ֱ��American Journal of Psychiatry, show that activity in the dorsal mid-insula could drive these different interpretations of bodily sensations in mental health. Increased awareness of the differences in how people experience physical symptoms could also be useful to those treating mental health disorders.

We all use exteroception – sight, smell, hearing, taste and touch – to navigate daily life. But interoception – the ability to interpret signals from our body – is equally important for survival, even though it often happens subconsciously.

“Interoception is something we are all doing constantly, although we might not be aware of it,” said lead author Dr Camilla Nord from the MRC Cognition and Brain Sciences Unit. “For example, most of us are able to interpret the signals of low blood sugar, such as tiredness or irritability, and know to eat something. However, there are differences in how our brains interpret these signals.”

Differences in interoceptive processes have previously been identified in people with eating disorders, anxiety and depression, panic disorder, addiction and other mental health disorders. Theoretical models have suggested that disrupted cortical processing drives these changes in interoceptive processing, conferring vulnerability to a range of mental health symptoms.

Nord and her colleagues combined brain imaging data from previous studies and compared differences in brain activity during interoception between 626 patients with mental health disorders and 610 healthy controls. “We wanted to find out whether there is something similar happening in the brain in people with different mental disorders, irrespective of their diagnosis,” she said.

Their analysis showed that for patients with bipolar, anxiety, major depression, anorexia and schizophrenia, part of the cerebral cortex called the dorsal mid-insula showed different brain activation when processing pain, hunger and other interoceptive signals when compared to the control group.

̽��ֱ��researchers then ran a follow-up analysis and found that the dorsal mid-insula does not overlap with regions of the brain altered by antidepressant drugs or regions altered by psychological therapy, suggesting that it could be studied as a new target for future therapeutics to treat differences in interoception.

“It’s surprising that in spite of the diversity of psychological symptoms, there appears to be a common factor in how physical signals are processed differently by the brain in mental health disorders,” said Nord. “It shows how intertwined physical and mental health are, but also the limitations of our diagnostic system – some important factors in mental health might be ‘transdiagnostic’, that is, found across many diagnoses.”

In future, Dr Nord is planning studies to test whether this disrupted activation could be altered by new treatments for mental health disorders, such as brain stimulation.

̽��ֱ��research was supported by NIHR Cambridge Biomedical Research Centre.

Reference:
Camilla L. Nord, Rebecca P. Lawson and Tim Dalgleish. ‘Disrupted dorsal mid-insula activation during interoception across psychiatric disorders.’ ̽��ֱ��American Journal of Psychiatry (2021). DOI: 10.1176/appi.ajp.2020.20091340

Researchers have shown why people with mental health disorders, including anorexia and panic disorders, experience physical signals differently.

In spite of the diversity of psychological symptoms, there appears to be a common factor in how physical signals are processed differently by the brain in mental health disorders: it shows how intertwined physical and mental health are

Camilla Nord

Geralt from Pixabay

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̽��ֱ��power of touch

ta385 — Thu, 17 Jun 2021 05:30:00 +0000

As a major Fitzwilliam Museum exhibition explores human touch through 4,000 years of art, Cambridge researchers explain why this sense is so important in their own work.

Talk with Your Hands: a Cambridge Shorts film

amb206 — Fri, 18 Nov 2016 09:10:00 +0000

Talk with Your Hands: Communicating across the Sensory Spectrum opens with Hayden Dahmm speaking to camera. He is studying engineering and he’s blind. One of the benefits of being blind, he suggests, is that he is not distracted by physical appearance. ̽��ֱ��words people use, and how they use them, gives him “a genuine impression of the speaker”.

Louise Stern is a writer and artist. She is deaf and explains that her native tongue is American Sign Language. Speaking with her hands, she says: “ ̽��ֱ��body is eloquent and conveys layers of emotion and meaning.” When she describes how eye contact is, for a deaf person, an especially beautiful thing, she hesitates – and then says “it makes me feel like they see me”.

In just ten minutes, Talk with Your Hands conveys the richness of verbal and non-verbal languages and explores how our senses overlap and merge. Through interviews with blind and deaf people, interwoven with insights from neuroscientists, the film demonstrates how we communicate with sounds and gestures – and how each mode of communication has its own characteristics.

Sign language is not a translation of, or substitute for, verbal language. While spoken language is linear (produced through the channels of our mouths one word at a time), sign language is flowing and simultaneous. Similarly, the spoken word is not just the written word spoken out loud. It’s much more than that, explains Hayden, rather as “poetry is the things that cannot be translated”.

̽��ֱ��capacity for language is what sets mankind apart from other animals. Years ago, scientists looking at brain damage identified the parts of the brain responsible for speaking and comprehension, for hearing and seeing. Now we know that this understanding of how the brain works is far too simplistic: language, and the different ways we use it, colonises most of the brain.

Talk with Your Hands is one of four films made by Cambridge researchers for the 2016 Cambridge Shorts series, funded by Wellcome Trust ISSF. ̽��ֱ��scheme supports early career researchers to make professional quality short films with local artists and filmmakers. Researchers Craig Pearson (Wellcome Trust-MRC Cambridge Stem Cell Institute) and Julio Chenchen Song (Department of Linguistics) collaborated with filmmaker Toby Smith.

̽��ֱ��capacity for language is what sets us apart from other animals. Talk with Your Hands, the third of four Cambridge Shorts films, explores the richness of sensory perception in interviews with blind and deaf people together with insights from neuroscientists.

Talk With Your Hands

Cambridge Shorts 2016 (Talk with Your Hands)

Actress Nadia Nadarajah recites a poem using British Sign Language

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Synaesthesia is more common in autism

sj387 — Wed, 20 Nov 2013 08:07:50 +0000

Synaesthesia involves people experiencing a ‘mixing of the senses’, for example, seeing colours when they hear sounds, or reporting that musical notes evoke different tastes. Autism is diagnosed when a person struggles with social relationships and communication, and shows unusually narrow interests and resistance to change. ̽��ֱ��team of scientists from Cambridge ̽��ֱ�� found that whereas synaesthesia only occurred in 7.2% of typical individuals, it occurred in 18.9% of people with autism.

On the face of it, this is an unlikely result, as autism and synaesthesia seem as if they should not share anything. But at the level of the brain, synaesthesia involves atypical connections between brain areas that are not usually wired together (so that a sensation in one channel automatically triggers a perception in another). Autism has also been postulated to involve over-connectivity of neurons (so that the person over-focuses on small details but struggles to keep track of the big picture).

̽��ֱ��scientists tested – and confirmed – the prediction that if both autism and synaesthesia involve neural over-connectivity, then synaesthesia might be disproportionately common in autism.

̽��ֱ��team, led by Professor Simon Baron-Cohen at the Autism Research Centre at Cambridge ̽��ֱ��, tested 164 adults with an autism spectrum condition and 97 adults without autism. All volunteers were screened for synaesthesia. Among the 31 people with autism who also had synaesthesia, the most common forms of the latter were ‘grapheme-colour’ (18 of them reported black and white letters being seen as coloured) and ‘sound-colour’ (21 of them reported a sound triggering a visual experience of colour). Another 18 of them reported either tastes, pains, or smells triggering a visual experience of colour.

Professor Baron-Cohen said: “I have studied both autism and synaesthesia for over 25 years and I had assumed that one had nothing to do with the other. These findings will re-focus research to examine common factors that drive brain development in these traditionally very separate conditions. An example is the mechanism ‘apoptosis,’ the natural pruning that occurs in early development, where we are programmed to lose many of our infant neural connections. In both autism and synaesthesia apoptosis may not occur at the same rate, so that these connections are retained beyond infancy.”

Professor Simon Fisher, a member of the team, and Director of the Language and Genetics Department at Nijmegen’s Max Planck Institute, added: “Genes play a substantial role in autism and scientists have begun to pinpoint some of the individual genes involved. Synaesthesia is also thought to be strongly genetic, but the specific genes underlying this are still unknown. This new research gives us an exciting new lead, encouraging us to search for genes which are shared between these two conditions, and which might play a role in how the brain forms or loses neural connections.”

Donielle Johnson, a Cambridge Gates Scholar who carried out the study as part of her Master’s degree, said: “People with autism report high levels of sensory hyper-sensitivity. This new study goes one step further in identifying synaesthesia as a sensory issue that has been overlooked in this population. This has major implications for educators and clinicians designing autism-friendly learning environments.”

People with autism are more likely to also have synaesthesia, suggests new research in the journal Molecular Autism.

Genes play a substantial role in autism and scientists have begun to pinpoint some of the individual genes involved

Professor Simon Fisher

Richard E. Cytowic

Synesthetic number form

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Natural barometer in birds evolved from ancient fish sense organ

bjb42 — Tue, 04 Sep 2012 16:10:14 +0000

Latest research shows that the ‘paratympanic organ’ (PTO) - the innate barometer in the middle ear of birds - evolved from a fish sense organ that detects jaw movement.

̽��ֱ��work, published in Nature Communications, sheds new light on the evolutionary trajectory of sensory systems after tetrapods left the oceans and moved onto land.

̽��ֱ��‘spiracular organ’ found in cartilaginous fishes (sharks and rays) and some bony fishes (including gars, sturgeons and lungfishes) is structurally similar to a bird’s PTO and located in the same position within the head, that is, in the wall of the ‘spiracle’ - the first gill slit - from which the middle ear cavity of all land vertebrates evolved.

Both organs contain motion-detecting hair cells, like those in the human inner ear used for hearing and balance. Ear drum movements in birds, and jaw movements in fish, respectively distort the PTO and spiracular organ, triggering the hair cells.

It has been proposed that birds use the PTO to detect air pressure, assisting with rapid changes in altitude. ̽��ֱ��organ is most complex in fast flyers such as swifts.

By combining gene expression with fate-mapping techniques in chicken embryos, scientists have been able to determine that the PTO stems from a unique ‘placode’ whose existence in birds had not previously been suspected. Placodes are specialised patches of thickened embryonic skin from which sense organs develop.

̽��ֱ��research by Dr Paul O’Neill was started in Dr Clare Baker’s lab in the Department of Physiology, Development and Neuroscience at the ̽��ֱ�� of Cambridge and completed in Dr Raj Ladher’s lab at the RIKEN Center for Developmental Biology in Kobe, Japan.

̽��ֱ��avian PTO was first described in 1911 by Giovanni Vitali at the ̽��ֱ�� of Siena. After initial excitement, which led to Vitali being nominated for the 1934 Nobel Prize in Physiology or Medicine, its existence was largely forgotten or ignored.

“ ̽��ֱ��discovery of this placode removes the only obstacle to accepting an evolutionary relationship between the avian PTO and the spiracular organ,” said Baker.

“ ̽��ֱ��PTO is also found in alligators and has been reported in the tuatara - the sole living representative of an ancient reptilian lineage distinct from lizards and snakes. Although its function in these species is unknown, it could relate to jaw movement. It is not clear why the PTO was lost in the other amniote lineages - mammals, turtles, lizards and snakes - but the PTO’s function is likely to have been modified in birds for detecting air pressure during flight.”

“It will be interesting to use modern molecular techniques to determine whether the PTO placode starts to develop in mammals, even if the organ itself is not found.”

̽��ֱ��UK research was funded by the BBSRC and the work in Japan was funded by the Japan Society for the Promotion of Science (JSPS) and RIKEN.

Previous work on sense organ development from Baker’s Cambridge lab, published in Nature Communications and Development, showed that the last common ancestor of all vertebrates with jaws (that is, all living vertebrates except lampreys and hagfishes) had a placode-derived system of electrosensory organs for detecting changes in the local electric field, used for hunting live prey.

New research indicates that a bird’s ability to detect changes in air pressure is the evolutionary remnant of an ancient sense organ found in sharks and sturgeons.

̽��ֱ��PTO’s function is likely to have been modified in birds for detecting air pressure during flight.

Clare Baker

Paul O'Neill

PTO organ with hair cells labelled in green

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