Study maps how brain recognise extensively varied faces at one go

December 27, 2016

Washington, Dec 27: Ever wondered how can you recognise whether your friend is happy or sad, at a glance? Also how can you recognise a friend, even if you haven't seen him/her in a decade?

BrainAnswering to all these, a recent study finds out how the brain recognise familiar faces with efficiency and ease, despite extensive variation in how they appear.

Researchers at Carnegie Mellon University in the US are closer than ever before to understand the neural basis of facial identification.

The study, published in the journal of Proceedings of the National Academy of Sciences (PNAS), used highly sophisticated brain imaging tools and computational methods to measure the real-time brain processes that convert the appearance of a face into the recognition of an individual.

“Our results provide a step towards understanding the stages of information processing that begin when an image of a face first enters a person's eye and unfold over the next few hundred milliseconds, until the person is able to recognize the identity of the face," said study author Mark D. Vida.

To determine, how the brain rapidly distinguishes faces, they researchers scanned the brains of four people using magnetoencephalography (MEG).

MEG allowed them to measure ongoing brain activity throughout the brain on a millisecond-by-millisecond basis while the participants viewed images of 91 different individuals with two facial expressions each: happy and neutral.

The participants indicated that when they recognised that the same individual's face was repeated, regardless of expression.

The MEG scans allowed the researchers to map out, for each of many points in time, which parts of the brain encode appearance-based information and which encode identity-based information.

The team also compared the neural data to behavioral judgments of the face images from humans, whose judgments were based mainly on identity-based information.

Then, they validated the results by comparing the neural data to the information present in different parts of a computational simulation of an artificial neural network that was trained to recognise individuals from the same face images.

“Combining the detailed timing information from MEG imaging with computational models of how the visual system works has the potential to provide insight into the real-time brain processes underlying many other abilities beyond face recognition," said another researcher David C. Plaut.

The researchers are hopeful that the findings might be used in the near future to locate the exact point at which the visual perception system breaks down in different disorders and injuries, ranging from developmental dyslexia to prosopagnosia or face blindness.

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News Network
June 20,2020

Washington, Jun 20: Pregnant and postpartum women are usually at a high risk of depression and anxiety - one in seven women struggle with symptoms in the perinatal period and the coronavirus pandemic is exacerbating those struggles according to a recent study.

The study was published in Frontiers in Global Women's Health, which found that the likelihood of maternal depression and anxiety has substantially increased during the health crisis.

"The social and physical isolation measures that are critically needed to reduce the spread of the virus are taking a toll on the physical and mental health of many of us," said Dr. Margie Davenport of the University of Alberta, Canada, who co-authored the study.

For new moms, those stresses come with side effects.

"We know that experiencing depression and anxiety during pregnancy and the postpartum period can have detrimental effects on the mental and physical health of both mother and baby that can persist for years," said Davenport.

Such effects can include premature delivery, reduced mother-infant bonding, and developmental delays in infants.

The study surveyed 900 women - 520 of whom were pregnant and 380 of whom had given birth in the past year - and asked about their depression and anxiety symptoms before and during the pandemic.

Before the pandemic began, 29 percent of those women experienced moderate to high anxiety symptoms, and 15 percent experienced depressive symptoms. During the pandemic, those numbers increased - 72 percent experienced anxiety and 41percent experienced depression.

Because lockdown measures have affected daily routines and access to gyms, researchers also asked women whether their exercise habits had changed. Of the women surveyed, 64 percent reduced their physical activity since the pandemic began, while 15 percent increased and 21 percent experienced no change.

Exercise is a known way to ease depression symptoms, so limited physical activity may result in an uptick in depressive symptoms. Indeed, the study found that women who engaged in at least 150 minutes of moderate physical activity a week had significantly lower symptoms of depression and anxiety.

The findings are somewhat limited given the fact that researchers could not survey women before the pandemic began (since they could not know a pandemic would occur). The women surveyed could only offer their pre-pandemic symptoms in hindsight.

Also, while the researchers asked women about their symptoms using validated measures, only mental health care professionals can validly diagnose an individual with depression or anxiety.

The study was specifically interested in the impact of COVID-19 on new moms, but Davenport says maternal mental health is a critical issue no matter the time.

"Even when we are not in a global pandemic, many pregnant and postpartum women frequently feel isolated whether due to being hospitalized, not having family or friends around or other reasons," she said.

"It is critical to increase awareness of the impact of social (and physical) isolation on the mental health of pregnant and postpartum women," Davenport added.

Increased awareness makes diagnosis and treatment - the ultimate goal - more likely.

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Agencies
April 4,2020

Washington D.C., Apr 4: While consuming a high-diet salt can result in high blood pressure, a recent study has revealed a link between salt-rich diet and weaker immune system.

The study was conducted under the leadership of the University Hospital Bonn, and the results were published in the journal Science Translational Medicine.

The research was conducted on mice that were fed a high-salt diet. Later, they were found to suffer from much more severe bacterial infections.

Human volunteers who consumed an additional six grams of salt per day also showed pronounced immune deficiencies.

The World Health Organization (WHO) has recommended a maximum amount of five grams of salt a day.

It corresponds approximately to one level teaspoon. In reality, however, many Germans exceed this limit considerably. 

Figures from the Robert Koch Institute suggest that on average men consume ten, and women more than eight grams a day.

This means that we reach for the salt shaker much more than is good for us. After all, sodium chloride, which is its chemical name, raises blood pressure and thereby increases the risk of heart attack or stroke.

"We have now been able to prove for the first time that excessive salt intake also significantly weakens an important arm of the immune system," said Prof. Dr. Christian Kurts from the Institute of Experimental Immunology at the University of Bonn.

This finding is unexpected, as some studies point in the opposite direction. For example, infections with certain skin parasites in laboratory animals heal significantly faster if these consume a high-salt diet.

The study also sheds light on the fact that the skin serves as a salt reservoir.

"Our results show that this generalization is not accurate," emphasized Katarzyna Jobin, lead author of the study.

The body keeps the salt concentration in the blood and in the various organs largely constant. Otherwise important biological processes would be impaired. The only major exception is the skin which functions as a salt reservoir of the body. This is why the additional intake of sodium chloride works so well for some skin diseases.

However, other parts of the body are not exposed to the additional salt consumed with food. Instead, it is filtered out by the kidneys and excreted in the urine.

"We examined volunteers who consumed six grams of salt in addition to their daily intake," said Prof. Kurts. This is roughly the amount contained in two fast-food meals, i.e. two burgers and two portions of French fries.

After one week, from the results, it showed that the immune cells coped much worse with bacteria after the test subjects had started to eat a high-salt diet.

In human volunteers, excessive salt intake also resulted in increased glucocorticoid levels.

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Agencies
May 2,2020

Clinician-scientists have found that Irish patients admitted to hospital with severe coronavirus (COVID-19) infection are experiencing abnormal blood clotting that contributes to death in some patients.

The research team from the Royal College of Surgeons in Ireland found that abnormal blood clotting occurs in Irish patients with severe COVID-19 infection, causing micro-clots within the lungs.

According to the study, they also found that Irish patients with higher levels of blood clotting activity had a significantly worse prognosis and were more likely to require ICU admission.

"Our novel findings demonstrate that COVID-19 is associated with a unique type of blood clotting disorder that is primarily focussed within the lungs and which undoubtedly contributes to the high levels of mortality being seen in patients with COVID-19," said Professor James O'Donnell from St James's Hospital in Ireland.

In addition to pneumonia affecting the small air sacs within the lungs, the research team has also hundreds of small blood clots throughout the lungs.

This scenario is not seen with other types of lung infection and explains why blood oxygen levels fall dramatically in severe COVID-19 infection, the study, published in the British Journal of Haematology said.

"Understanding how these micro-clots are being formed within the lung is critical so that we can develop more effective treatments for our patients, particularly those in high-risk groups," O'Donnell said.

"Further studies will be required to investigate whether different blood-thinning treatments may have a role in selected high-risk patients in order to reduce the risk of clot formation," Professor O'Donnell added.

According to the study, emerging evidence also shows that the abnormal blood-clotting problem in COVID-19 results in a significantly increased risk of heart attacks and strokes.

As of Friday morning, the cases increased to 20,612 cases in Ireland, with 1,232 deaths so far, according to the Johns Hopkins University.

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