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
July 10,2020

Toronto, Jul 10: Pasteurising breast milk at 62.5 degrees Celsius for 30 minutes inactivates the SARS-CoV-2 virus that causes Covid-19, making it safe for consumption by babies, a study claims.

According to the research published in the Canadian Medical Association Journal, current advice for women with Covid-19 is to continue to breastfeed their own infants.

In Canada, it is standard care to provide pasteurised breast milk to very-low-birth-weight babies in hospital until their own mother's milk supply is adequate, the researchers said.

"In the event that a woman who is Covid-19-positive donates human milk that contains SARS-CoV-2, whether by transmission through the mammary gland or by contamination through respiratory droplets, skin, breast pumps and milk containers, this method of pasteurisation renders milk safe for consumption," said Sharon Unger, a professor at the University of Toronto in Canada.

The Holder method, a technique used to pasteurise milk in all Canadian milk banks at 62.5 degrees Celsius for 30 minutes, is effective at neutralising viruses such as HIV, hepatitis and others that are known to be transmitted through human milk, the researchers said.

In the latest study, the researchers spiked human breast milk with a viral load of SARS-CoV-2 and tested samples that either sat at room temperature for 30 minutes or were warmed to 62.5 degrees Celsius for 30 minutes.

They then measured for active virus, finding that the virus in the pasteurised milk was inactivated after heating.

More than 650 human breast milk banks around the world use the Holder method to ensure a safe supply of milk for vulnerable infants, the researchers said.

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Agencies
August 2,2020

Washington, Aug 2: Children under the age of five have between 10 to 100 times greater levels of genetic material of the coronavirus in their noses compared to older children and adults, a study in JAMA Pediatrics said Thursday.

Its authors wrote this meant that young children might be important drivers of Covid-19 transmission within communities -- a suggestion at odds with the current prevailing narrative.

The paper comes as the administration of US President Donald Trump is pushing hard for schools and daycare to reopen in order to kickstart the economy.

Between March 23 and April 27, researchers carried out nasal swab tests on 145 Chicago patients with mild to moderate illness within one week of symptom onset.

The patients were divided into three groups: 46 children younger than five-years-old, 51 children aged five to 17 years, and 48 adults aged 18 to 65 years.

The team, led by Dr Taylor Heald-Sargent of the Ann & Robert H. Lurie Children's Hospital, observed, "a 10-fold to 100-fold greater amount of SARS-CoV-2 in the upper respiratory tract of young children."

15 countries with the highest number of cases, deaths due to the Covid-19 pandemic

The authors added that a recent lab study had demonstrated that the more viral genetic material was present, the more infectious virus could be grown.

It has also previously been shown that children with high viral loads of the respiratory syncytial virus (RSV) are more likely to spread the disease.

"Thus, young children can potentially be important drivers of SARS-CoV-2 spread in the general population," the authors wrote.

"Behavioral habits of young children and close quarters in school and daycare settings raise concern for SARS-CoV-2 amplification in this population as public health restrictions are eased," they concluded.

The new findings are at odds with the current view among health authorities that young children -- who, it has been well established, are far less likely to fall seriously ill from the virus -- don't spread it much to others either.

However, there has been fairly little research on the topic so far.

One recent study in South Korea found children aged 10 to 19 transmitted Covid-19 within households as much as adults, but children under nine transmitted the virus at lower rates.

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News Network
February 22,2020

Feb 22: The subjective feeling of well-being experienced by many people with the practice of meditation is associated with specific changes in the brain, according to a study which may lead to better clinical recommendations of the practice.

The study, published in the journal Brain and Cognition, examined the effects of the technique known as Transcendental Meditation (TM), which consists of the silent repetition of a meaningless sound.

In the study, the researchers from the IMT School for Advanced Studies Lucca in Italy, enrolled 34 healthy young volunteers and divided them in two groups.

They said the first group practised TM 40 minutes per day in two sessions of 20 minutes each, one in the morning and the other in the evening.

The second group, the scientists said, did not change its daily routine.

Using questionnaires, they also measured the anxiety and stress levels of all the participants at the beginning of the study, as well as the subjects' ability to manage stressful situations.

According to the researchers, the participants were also subjected to a functional magnetic resonance imaging (fMRI) brain scan, in order to measure the organ's activity at rest, and changes in the excitation among different cerebral areas.

They repeated the tests after three months, at the end of the study.

According to the study, the levels of anxiety and stress perceived by the subjects who followed the meditation program were significantly reduced in comparison with those of the volunteers who did not practice TM.

"Magnetic resonance imaging also shows that the reduction of anxiety levels is associated with specific changes in the connectivity between different cerebral areas, such as precuneus, left parietal lobe and insula, which all have an important role in the modulation of emotions and inner states," said study co-author Giulia Avvenuti from the IMT School for Advanced Studies Lucca.

"In the control group, instead, none of these changes was observed. The fact that Transcendental Meditation has measurable effects on the 'dialogue' between brain structures involved in the modulation of affective states opens new perspectives for the understanding of brain-mind relationships," said Pietro Pietrini, IMT School's Director, and co-author of the study.

"It also extends the results of recent research suggesting that drugs therapies and psychotherapy leverage on the same biological mechanism," Pietrini said.

According to the researchers, even a few months of practice of TM can have positive effects which can be correlated with measurable changes in the brain.

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