Science Bites seeks to compile the latest scientific research updates in bite-sized forms.

1. Brain function can be preserved by cooling bodies following cardiac arrest

The American Academy of Neurology has studied the beneficial effects of reducing body temperature to maintain brain function after a cardiac arrest. The new guidelines state that reducing a comatose person's body temperature down to 32 to 34 degrees Celsius from 37 degrees Celsius for 24 hours after a cardiac arrest could very likely improve brain outcomes.

“This issue with brain protection after cardiac resuscitation has been an active topic in the academic literature for a number of years,” said Dr Alejandro Rabinstein, a neurologist at the Mayo Clinic in America and co-author of the new guidelines.

It was reported that only about 6% to 10% of patients who suffer a cardiac arrest outside of a hospital live long enough to ultimately return home. Rabinstein added that, If the heart does get restarted, one of the main factors that influence the ultimate outcome is brain health. “Improving neurological outcomes is really improving overall outcomes,” he explained.

After examining evidence from two studies, researchers recommend cooling or ‘therapeutic hypothermia’ in these comatose patients whose heart rhythm was restored with defibrillation outside of a hospital. The scientists also said that cooling a person to 36 degrees Celsius for a day, warming the body to 37 degrees Celsius after and then maintaining the temperature at 37.5 degrees Celsius is possibly just as effective as cooling the patient for a day.

The reasoning behind the beneficial effect has yet to be established. Methods of providing therapeutic hypothermia in hospitals include the use of chilled intravenous fluids, special vests and other pieces of clothing.

2. Human umbilical cord blood can restore learning and memory

Stanford University School of Medicine researchers injected human cord blood into elderly mice and found an enhancement in brain performance. Improvements in learning and memory tests were detected and they even started nesting again, collecting cotton wads to make beds, an intuitive behaviour that is mostly forgotten in old age.

Dr James Pickett, Alzheimer’s Society head of research said, “Everyone experiences some decline in memory as they get older. The possibility that this process can be reversed by an infusion of young blood sounds like the stuff of science fiction, but this is what the study is beginning to show.”

The beneficial effects stem from a protein in the cord blood that is believed to encourage neuroplasticity in the brain, permitting neurons to adapt and communicate more effectively. It targets the hippocampus in the brain to aid in producing long-term memories as well as generates memory of spatial information, for example, how to return to your car or autobiographical events like what you consumed for breakfast.

Study authors believe this first-of-its-kind discovery increases chances of the same effect in humans. Senior author, Dr Tony Wyss-Coray said, “Neuroscientists have ignored it and are still ignoring it, but to me it’s remarkable that something in your blood can influence the way you think.”

“For largely unknown reasons, the hippocampus is especially vulnerable to normal aging. With advancing age, the hippocampus degenerates, loses nerve cells and shrinks. Hippocampal deterioration is also an early manifestation of Alzheimer’s disease. Our results argue that systemic factors present early in life may be beneficial for revitalisation of aged tissue and that (the protein) represents such a restorative factor for the aged hippocampus,” he shared.

Researchers at CalTech were able to accurately identify 200 neurons in the monkey brain specific for facial recognition. Photo credit: Doris Tsao/CalTech/New York Times
Researchers at CalTech were able to accurately identify 200 neurons in the monkey brain specific for facial recognition. Photo credit: Doris Tsao/CalTech/New York Times

3. Scientists have cracked the code of how faces are recognised

A study of the facial recognition phenomenon has finally yielded some exciting results. Two Caltech biologists, Le Chang and Doris Y Tsao conducted experiments based on electrical recordings from face cells, named because these neurons respond with a surge of electric signals when a facial image is presented to the retina.

These scientists manipulated photos of 2,000 human faces and detected the face cells response in macaque monkeys. This way, the team established that aspects of the faces activated the cells and learnt how the facial features were encoded. Biologists said that just 200 face cells are essential to memorise a face. Upon determining how its features are encoded, scientists could reconstruct the faces a monkey saw just by observing the pattern of face cell signals.

This new study discredits previous research that believed neurons in face patches encoded particular people, as opposed to just facial features. “It really speaks to how compact and efficient this feature-based neural code is,” said Tsao. It may also justify how we can possibly recognise billions of distinctive people without requiring an equally large number of face cells.

Study authors are eager to discover the depths of this new finding and how It can impact humans as whole whether in studying diseases such as Alzheimer’s disease or even crime. Tsao said, “One can imagine applications in forensics where one could reconstruct the face of a criminal by analysing a witness's brain activity.” MIMS

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