Posts tagged oxytocin

Prosopagnosia (face blindness) may be temporarily improved following inhalation of the hormone oxytocin.

This is the finding of research led by Dr Sarah Bate and Dr Rachel Bennetts of the Centre for Face Processing Disorders at Bournemouth University that will be presented today, Friday 6 September, at the British Psychological Society’s Joint Cognitive and Developmental annual conference at the University of Reading.

Dr Bate explained: “Prosopagnosia is characterised by a severe impairment in face recognition, whereby a person cannot identify the faces of their family or friends, or even their own face”

The researchers tested twenty adults (10 with prosopagnosia and 10 control participants). Each participant visited the laboratory on two occasions, approximately two weeks apart. On one visit they inhaled the oxytocin nasal spray, and on the other visit they inhaled the placebo spray. The two sprays were prepared by an external pharmaceutical company in identical bottles, and neither the participants nor the researchers knew the identity of the sprays until the data had been analysed.

Regardless of which spray the person inhaled, the testing sessions had an identical format. Participants inhaled the spray, then sat quietly for 45 minutes to allow the spray to take effect. They then participated in two face processing tests: one testing their ability to remember faces and the other testing their ability to match faces of the same identity.

The researchers found that the participants with prosopagnosia achieved higher scores on both face processing tests in the oxytocin condition. Interestingly, no improvement was observed in the control participants, suggesting the hormone may be more effective in those with impaired face recognition systems.

The initial ten participants with prosopagnosia had a developmental form of the condition. Individuals with developmental prosopagnosia have never experienced brain damage, and this form of face blindness is thought to be very common, affecting one in 50 people. Much more rarely, people can acquire prosopagnosia following a brain injury. At a later date, the researchers had the opportunity to test one person with acquired prosopagnosia, and also observed a large improvement following oxytocin inhalation in this individual.

Dr Bate said: “This study provides the first evidence that oxytocin may be used to temporarily improve face recognition in people with either developmental or acquired prosopagnosia. The effects of the hormone are thought to last 2-3 hours, and it may be that the nasal spray can be used to improve face recognition on a special occasion. However, much more research needs to be carried out, as we don’t currently know whether there are benefits or risks associated with longer-term inhalation of the hormone.”

(Source: alphagalileo.org)

A new study in Biological Psychiatry explores the influence of oxytocin

Difficulty in registering and responding to the facial expressions of other people is a hallmark of autism spectrum disorder (ASD). Relatedly, functional imaging studies have shown that individuals with ASD display altered brain activations when processing facial images.

The hormone oxytocin plays a vital role in the social interactions of both animals and humans. In fact, multiple studies conducted with healthy volunteers have provided evidence for beneficial effects of oxytocin in terms of increased trust, improved emotion recognition, and preference for social stimuli.

This combination of scientific work led German researchers to hypothesize about the influence of oxytocin in ASD. Dr. Gregor Domes, from the University of Freiburg and first author of the new study, explained: “In the present study, we were interested in the question of whether a single dose of oxytocin would change brain responses to social compared to non-social stimuli in individuals with autism spectrum disorder.”

They found that oxytocin did show an effect on social processing in the individuals with ASD, “suggesting that oxytocin may help to treat a basic brain function that goes awry in autism spectrum disorders,” commented Dr. John Krystal, Editor of Biological Psychiatry.

To conduct this study, they recruited fourteen individuals with ASD and fourteen control volunteers, all of whom completed a face- and house-matching task while undergoing imaging scans. Each participant completed this task and scanning procedure twice, once after receiving a nasal spray containing oxytocin and once after receiving a nasal spray containing placebo. The order of the sprays was randomized, and the tests were administered one week apart.

Using two sets of stimuli in the matching task, one of faces and one of houses, allowed the researchers to not only compare the effects of the oxytocin and placebo administrations, but also allowed them to discriminate findings between specific effects to only social stimuli and non-specific effects to more general brain processing.

What they found was intriguing. The data indicate that oxytocin specifically increases responses of the amygdala to social stimuli in individuals with ASD. The amygdala, the authors explain, “has been associated with processing of emotional stimuli, threat-related stimuli, face processing, and vigilance for salient stimuli”.

This finding suggests oxytocin might promote the salience of social stimuli in ASD. Increased salience of social stimuli might support behavioral training of social skills in ASD.

These data support the idea that oxytocin may be a promising approach in the treatment of ASD and could stimulate further research, even clinical trials, on the exploration of oxytocin as an add-on treatment for individuals with autism spectrum disorder.

(Source: alphagalileo.org)

Finding shows oxytocin strengthens bad memories and can increase fear and anxiety

It turns out the love hormone oxytocin is two-faced. Oxytocin has long been known as the warm, fuzzy hormone that promotes feelings of love, social bonding and well-being. It’s even being tested as an anti-anxiety drug. But new Northwestern Medicine® research shows oxytocin also can cause emotional pain, an entirely new, darker identity for the hormone.

Oxytocin appears to be the reason stressful social situations, perhaps being bullied at school or tormented by a boss, reverberate long past the event and can trigger fear and anxiety in the future.

That’s because the hormone actually strengthens social memory in one specific region of the brain, Northwestern scientists discovered.

If a social experience is negative or stressful, the hormone activates a part of the brain that intensifies the memory. Oxytocin also increases the susceptibility to feeling fearful and anxious during stressful events going forward. 

(Presumably, oxytocin also intensifies positive social memories and, thereby, increases feelings of well being, but that research is ongoing.)

The findings are important because chronic social stress is one of the leading causes of anxiety and depression, while positive social interactions enhance emotional health. The research, which was done in mice, is particularly relevant because oxytocin currently is being tested as an anti-anxiety drug in several clinical trials.

“By understanding the oxytocin system’s dual role in triggering or reducing anxiety, depending on the social context, we can optimize oxytocin treatments that improve well-being instead of triggering negative reactions,” said Jelena Radulovic, the senior author of the study and the Dunbar Professsor of Bipolar Disease at Northwestern University Feinberg School of Medicine. The paper was published July 21 in Nature Neuroscience.

This is the first study to link oxytocin to social stress and its ability to increase anxiety and fear in response to future stress. Northwestern scientists also discovered the brain region responsible for these effects — the lateral septum – and the pathway or route oxytocin uses in this area to amplify fear and anxiety.

The scientists discovered that oxytocin strengthens negative social memory and future anxiety by triggering an important signaling molecule — ERK (extracellular signal regulated kinases) — that becomes activated for six hours after a negative social experience. ERK causes enhanced fear, Radulovic believes, by stimulating the brain’s fear pathways, many of which pass through the lateral septum. The region is involved in emotional and stress responses.

The findings surprised the researchers, who were expecting oxytocin to modulate positive emotions in memory, based on its long association with love and social bonding.

“Oxytocin is usually considered a stress-reducing agent based on decades of research,” said Yomayra Guzman, a doctoral student in Radulovic’s lab and the study’s lead author. “With this novel animal model, we showed how it enhances fear rather than reducing it and where the molecular changes are occurring in our central nervous system.’

The new research follows three recent human studies with oxytocin, all of which are beginning to offer a more complicated view of the hormone’s role in emotions.

All the new experiments were done in the lateral septum. This region has the highest oxytocin levels in the brain and has high levels of oxytocin receptors across all species from mice to humans.

“This is important because the variability of oxytocin receptors in different species is huge,” Radulovic said. “We wanted the research to be relevant for humans, too.”

Experiments with mice in the study established that 1) oxytocin is essential for strengthening the memory of negative social interactions and 2) oxytocin increases fear and anxiety in future stressful situations.

Experiment 1: Oxytocin Strengthens Bad Memories

Three groups of mice were individually placed in cages with aggressive mice and experienced social defeat, a stressful experience for them. One group was missing its oxytocin receptors, essentially the plug by which the hormone accesses brain cells. The lack of receptors means oxytocin couldn’t enter the mice’s brain cells. The second group had an increased number of receptors so their brain cells were flooded with the hormone. The third control group had a normal number of receptors.

Six hours later, the mice were returned to cages with the aggressive mice. The mice that were missing their oxytocin receptors didn’t appear to remember the aggressive mice and show any fear. Conversely, when mice with increased numbers of oxytocin receptors were reintroduced to the aggressive mice, they showed an intense fear reaction and avoided the aggressive mice.

Experiment 2: Oxytocin Increases Fear and Anxiety in Future Stress

Again, the three groups of mice were exposed to the stressful experience of social defeat in the cages of other more aggressive mice. This time, six hours after the social stress, the mice were put in a box in which they received a brief electric shock, which startles them but is not painful. Then 24 hours later, the mice were returned to the same box but did not receive a shock.

The mice missing their oxytocin receptors did not show any enhanced fear when they re-entered the box in which they received the shock. The second group, which had extra oxytocin receptors showed much greater fear in the box. The third control group exhibited an average fear response.

“This experiment shows that after a negative social experience the oxytocin triggers anxiety and fear in a new stressful situation,” Radulovic said.

(Source: northwestern.edu)

The so-called trust hormone, oxytocin, may not improve the symptoms of children with autism, a large study led by UNSW researchers has found.

Professor Mark Dadds, of the UNSW School of Psychology, says previous research suggested that oxytocin – a hormone with powerful effects on brain activity linked to the formation of social bonds – could have benefits for children with the disorder.

“Many parents of children with autism are already obtaining and using oxytocin nasal spray with their child, and clinical trials of the spray’s effects are underway all over the world. Oxytocin has been touted as a possible new treatment, but its effects may be limited,” Professor Dadds says.

Autism is a complex condition of unknown cause in which children exhibit reduced interest in other people, impaired social communication skills and repetitive behaviours.

To determine its suitability as a general treatment Professor Dadds’ team conducted a randomised controlled clinical trial of 38 boys aged between seven and 16 years of age with autism. Half were given a nasal spray of oxytocin on four consecutive days.

The study has been accepted for publication in the Journal of Autism and Developmental Disorders.

“We found that, compared to a placebo, oxytocin did not significantly improve emotion recognition, social interaction skills, repetitive behaviours, or general behavioural adjustment,” says Professor Dadds.

“This is in contrast to a handful of previous smaller studies which have shown some positive effects on repetitive behaviours, social memory and emotion processing.

“These studies, however, were limited by having small numbers of participants and/or by looking at the effects of single doses of oxytocin on specific behaviours or cognitive effects while the participants had the oxytocin in their system.

“The results of our much larger study suggest caution should be exercised in recommending nasal oxytocin as a general treatment for young people with autism.”

The boys in the new study were assessed twice before treatment, three times during the treatment week, immediately afterwards and three months later, with a parent present. Factors such as eye contact with the parent, responsiveness, warmth, speech, positive body language, repetitive behaviours, and recognition of facial emotions were observed.

Research in people who are healthy shows oxytocin can increase levels of trust and eye-gazing and improve their identification of emotions in others.

One likely possibility is that many children with autism have impaired oxytocin receptor systems that do not respond properly, Professor Dadds says. But there may be a subgroup of children for whom oxytocin could be beneficial, and research is needed to determine who responds to it and how best to deliver it.

(Source: newsroom.unsw.edu.au)

People with genes that make it tough for them to engage socially with others seem to be better than average at hypnotizing themselves. A study published today in Psychoneuroendocrinology concludes that such individuals are particularly good at becoming absorbed in their own internal world, and might also be more susceptible to other distortions of reality.

Psychologist Richard Bryant of the University of New South Wales in Sydney and his colleagues tested the hypnotizability of volunteers with different forms of the receptor for oxytocin, a hormone that increases trust and social bonding. (Oxytocin’s association with emotional attachment also earned it the nickname of ‘love hormone’.) Those with gene variants linked to social detachment and autism were found to be most susceptible to hypnosis.

Hypnosis has intrigued scientists since the nineteenth-century physician James Braid used it to alleviate pain in a variety of medical conditions, but it has never been fully understood. Hypnotized people can undergo a range of unusual experiences, including amnesia, anaesthesia and the loss of the ability to move their limbs. But some individuals are more affected by hypnosis than others — and no one knows why.

Hormones and hypnotism

How susceptible someone is to persuasion is an important factor in how easily they can be hypnotized by someone else. Bryant and his colleagues have previously shown that spraying a shot of oxytocin up people’s noses makes them more hypnotizable, and more likely to engage in potentially embarrassing activities such as swearing or dancing at a hypnotist’s suggestion.

When it comes to self-hypnosis, however, the team wondered whether people who can easily disengage from the external world and become lost in their own imagination might do better. In their latest study, they asked 185 volunteers to hypnotize themselves with the aid of an audio recording, then assessed the depth of their hypnosis using checks such as whether they were unable to open their eyes, or could hallucinate a sound.

The researchers used a questionnaire to test the participants’ ability to become absorbed in internal and imagined experiences, and tested them for variants of the oxytocin-receptor gene at two places in the gene sequence — rs53576 and rs2254298 — that that increase the risk of social detachment and autism. Participants with these variants scored highest for hypnotizability and absorption.

Bryant suggests that as well as being more hypnotizable, such individuals might “be influenced to have a range of experiences that more reality-based people cannot”. For example, this capacity might help to explain why some people respond better to placebos, or are more likely to accept paranormal or religious experiences.

“At this point we do not know anything about genetic bases of suggestibility per se,” says Bryant. “The current finding does provide some direction for exploring this.”

Aleksandr Kogan of the University of Cambridge, UK, who works on the genetics of social psychology, says that the results fit well with what is known about the oxytocin-receptor gene, particularly for variants at site rs53576. Among white people, these influence an individual’s sensitivity to social cues, he says. “That this would reflect a difference in internal experiences makes sense.”

(Source: nature.com)