Brain gain: Secret of crows' intelligence decoded

Brain gain: Secret of crows' intelligence decoded
Behavioural biologists have even called crows "feathered primates" because the birds make and use tools, are able to remember large numbers of feeding sites, and plan their social behaviour according to what other members of their group do.
BERLIN: Crows are no bird-brains! Scientists have for the first time demonstrated how the brains of crows produce intelligent behaviour when the birds have to make strategic decisions.

Researchers have long suspected that corvids - the family of birds including ravens, crows and magpies - are highly intelligent.

Behavioural biologists have even called crows "feathered primates" because the birds make and use tools, are able to remember large numbers of feeding sites, and plan their social behaviour according to what other members of their group do.

This high level of intelligence might seem surprising because birds' brains are constructed in a fundamentally different way from those of mammals, including primates - which are usually used to investigate these behaviours.

Neurobiologists Lena Veit and Professor Andreas Nieder from Eberhard Karls University of Tubingen in Germany investigated the brain physiology of crows' intelligent behaviour.

They trained crows to carry out memory tests on a computer. The crows were shown an image and had to remember it. Shortly afterwards, they had to select one of two test images on a touchscreen with their beaks based on a switching behavioural rules.

One of the test images was identical to the first image, the other different. Sometimes the rule of the game was to select the same image, and sometimes it was to select the different one.

The crows were able to carry out both tasks and to switch between them as appropriate. That demonstrates a high level of concentration and mental flexibility which few animal species can manage - and which is an effort even for humans.

The crows were quickly able to carry out these tasks even when given new sets of images. The researchers observed neuronal activity in the nidopallium caudolaterale, a brain region associated with the highest levels of cognition in birds.

One group of nerve cells responded exclusively when the crows had to choose the same image - while another group of cells always responded when they were operating on the "different image" rule.

By observing this cell activity, the researchers were often able to predict which rule the crow was following even before it made its choice.

The study published in Nature Communications provides valuable insights into the parallel evolution of intelligent behaviour.

"Many functions are realised differently in birds because a long evolutionary history separates us from these direct descendants of the dinosaurs," said Lena Veit.

"This means that bird brains can show us an alternative solution out of how intelligent behaviour is produced with a different anatomy," Veit said.

Alzheimer's a late stage of diabetes: Study


LONDON: Scientists have found that Alzheimer's - a neurodegenerative disorder - may actually be a late stage of Type 2 diabetes.

The findings also suggest that losing weight and exercising may ward off Alzheimer's, at least in the very early stages, researchers said.

The extra insulin produced by those with Type 2 diabetes also gets into the brain, disrupting its chemistry, which can lead to the formation of toxic clumps of amyloid proteins that poison brain cells, researchers said.

"The discovery could explain why people who develop T2 diabetes often show sharp declines in cognitive function, with an estimated 70 per cent developing Alzheimer's - far more than in the rest of the population," said Ewan McNay at Albany University in New York.

"People who develop diabetes have to realise this is about more than controlling their weight or diet. It's also the first step on the road to cognitive decline," McNay said.

The increased risk of Alzheimer's disease in Type 2 diabetics has been known for a long time.

McNay's research aimed at discovering the mechanism by which T2 diabetes might cause Alzheimer's.

He fed rats on a high-fat diet to induce T2 diabetes and then carried out memory tests, showing that the animals' cognitive skills deteriorated rapidly as the disease progressed, 'The Sunday Times' reported.

An examination of their brains showed clumps of amyloid protein had formed, of the kind found in the brains of Alzheimer's patients.

McNay suggests that, in people with Type 2 diabetes, the body becomes resistant to insulin, a hormone that controls blood-sugar levels - so the body produces more of it.

However, some of that insulin also makes its way into the brain, where its levels are meant to be controlled by the same enzyme that breaks down amyloid.

"High levels of insulin swamp this enzyme so that it stops breaking down amyloid. The latter then accumulates until it forms toxic clumps that poison brain cells. It's the same amyloid build-up to blame in both diseases - T2 diabetics really do have low-level Alzheimer's," McNay said.

The research was presented at the Society for Neuroscience meeting in San Diego.

New test can warn patients at high risk of heart attack

PUNE: Lives of patients at the risk of a heart attack can now be saved with a non-invasive test that can identify high-risk unstable blockages that may rupture to cause a heart attack or other serious coronary event.

Unlike the traditional diagnostic techniques that have so far revolved around finding the tightest narrowing of the arteries supplying blood to the heart, the new test identifies narrowing that does not cause severe blockage, but can rupture and cause a heart attack. The test is a combination of a radioactive tracer and scanning technique, and will take at least five to 10 years to come in the public domain.

British medical journal Lancet published the new study on November 11, 2013 on the use of radioactive tracer 18 f-sodium fluoride (18F-Naf), a known tracer in bone imaging, to accurately identify the blockages that may cause a heart attack.

The research was conducted by a team led by Ahmednagar-born cardiologist Nikhil Joshi at the British Heart Foundation Centre for Cardiovascular Science in Edinburgh, UK, which found that the use of the radioactive tracer with a scanning technique known as positron emission tomography (PET) and computed tomography (CT) could identify the risk of a heart attack and how this would eventually help in initiating early treatment to prevent it.

The test technique is simple: inject the tracer into the patient's veins, followed by a special PET-CT scan, which is commonly used in cancer diagnosis. The fatty plaques in the arteries pumping blood into the heart 'light up' if the plaque (a fatty deposit inside an arterial wall) is at the risk of rupturing. Experts call it detecting the 'ticking time bomb' inside the body.

The new test will mark a paradigm shift in cardiac diagnostics. "Until now, there were no non-invasive imaging techniques available that can identify high-risk and ruptured coronary plaques in patients of heart disease. For the first time, we have shown this is possible and this new technique that can identify high-risk or ruptured coronary plaques, has the potential to transform how we identify, manage and treat patients with stable and unstable heart disease. The next step will be to conduct larger-scale trials of 18F-NaF imaging to assess whether increased coronary 18F-NaF activity is ultimately predictive of future adverse effects," Joshi told TOI in an interview on email.

Elaborating, Joshi said, "The technique is primarily aimed at targeting unstable plaques irrespective of the degree of obstruction. Hence it is possible to diagnose even smaller levels of obstruction, like say 20- 30%, that can rupture if unstable, even in younger patients leading to severe heart attack."

While the technique can be used anywhere in the world, Joshi says it is more relevant in India because of high prevalence of diabetes and coronary disease owing to changing lifestyles.

"However, this is not a screening test for the general population. Its utility is for patients at risk of coronary disease, and patients with angina and previous heart attacks. Moreover, this is an evolving area of research and future studies will determine which patient population will benefit from this type of a scan," Joshi said.

Peer appreciation for the research is pouring in. "It is commendable to have an Indian do such a brilliant research and that too as a principal investigator. The diagnostic method will help identify vulnerable patients," said cardiac surgeon Chandrashekhar Kulkarni of Jehangir Hospital.