Risk Takers Turn Risk Aversive:

We do not normally take risks. Yet, at times, we do. Scientists in Stanford University tell us why, in the recent issue of Nature. They have succeeded in turning risk taking rats into risk aversive ones by timely stimulation of dopamine type 2 receptors in some specific cells of the Nucleus accumbens.

The nucleus accumbens is generally considered the reward centre in the brain and is implicated in addiction. But given the results that are pouring in about the nucleus, perhaps it is more involved in decision making than in addiction.

Nature 531,642–646 (31 March 2016)

New method for dieting: Brain control

The sense of hunger and feeling of satiation after eating are mediated by cells in the lower part of the hypothalamus in the brain. Scientists have found ways to remotely activate and inhibit this region specifically without any surgical intervention. Genetically encoded nanoparticles that respond to radio signals of magnetic stimulation were used to activate glucose-sensing neurons in the ventromedial hypothalamus of live rats. This was found to increase plasma glucose and glucagon, lower insulin levels and stimulate feeding. Inhibition reduces blood glucose, raises insulin levels and suppresses feeding.

So, if you have been planning to diet and never got around to doing it yet, wait for some more time. The technique demonstrated in the lab might soon be around since there is enough demand.

Nature 531, 647–650 (31 March 2016)

Mobile Phones to Measure Tidal Forces

Many cell phones today have microelectromechanical systems that can detect acceleration. By tweaking the system a little, these devices can detect acceleration due to gravity, claims a paper in a recent issue of Nature.

The new device is sensitive enough to detect tidal forces on earth. From being a mere accelerometer, it becomes a gravimeter that can measure tidal forces.

Most present gravimeters are heavy. But this new device is so light that you can use it on a drone and let it survey the land. It will give you clues about underground reservoirs of oil, magma etc.

By putting the device into handphones, and crowdsourcing the data while people travel around, we will be able to map what lies underground.

Nature 531, 614–61(31 March 2016)

Unpunished corruption leads to more corruption

In our society, many cases of corruption go unpunished. Prevalence of rule violations (corruption, tax evasion etc.) tends to reduce intrinsic honesty in young people, says a recent paper in Nature.

More than 2500 young people from 23 countries took part in the experiment. Researchers conclude that

"weak institutions and cultural legacies that generate rule violations not only have direct adverse economic consequences, but might also impair individual intrinsic honesty that is crucial for the smooth functioning of society".

The message is clear: if you want to reduce corruption and tax evasion, punish the guilty and let the public know that economic offences will not be tolerated. This would have implications on lying and dishonest behaviour even in other realms of day-to-day life.

Regeneration of Lens after Cataract Operation

In the latest issue of Nature, there is a report of lens regeneration after cataract operation. Till now this was thought to be impossible. But Chinese and US scientists joined hands to prove that it is indeed possible. The trick is simple enough: when you remove the lens, be careful not to remove stem cells. But in practice, it requires a totally different operating procedure. Scientists find that if they retain cells that express Pax6 and Bmi1 genes, lens does regenerate and visual function is restored.

They first did experiments on rabbits and macaques. And they demonstrated that the same procedure works in human infants with cataract.

Cataract is one of the leading causes of blindness. The finding that it is feasible to allow the lens to regenerate using endogenous cells may revolutionise cataract operations.

Dilemma of being a neuron

If you were a neuron, you would need fast excitatory transmission and fast synaptic inhibition. The first - fast excitatory transmission - is mediated by AMPA and the second - inhibition - is mediated by GABA.

Since the inhibition by GABA is mostly in the synapses and the excitation is in the body of the neuron, you will have to package them and transport them to two different destinations. Or you could just send them generally to the plasma membrane and let them settle down where they are needed. 

What will you do?

If neurons were people, the answer would have been easy. But neurons don't talk. So you have to quiz them with scientific procedures and protocols. A recent paper in PNAS, Differential vesicular sorting of AMPA and GABAA receptors, does just that. Using total internal reflection fluorescence microscopy  in combination with immunocytochemistry, electrophysiology, and electron microscopy methods they confirm what method neurons use to distribute the receptors in different parts of the cell membrane.

Here is a short video from the report:

It appears that neurons are rather sensible. They package the goods into vesicles in golgi bodies and transport them separately to different destinations as per the need.

Does Winning an Election Increase Corruption?

Winning a competition contributes to subsequent unethical behavior, claims a paper in PNAS, based on a series of studies. Winners behave more dishonestly than competition losers.

The paper by Amos Schurra and Ilana Ritov from Israel provides evidence to show that winning a competition increases the likelihood of winners stealing money from their counterparts in a subsequent unrelated task. But the effect holds only when winning means performing better than others and not when success is determined by chance or in reference to a personal goal. The results also show that a possible mechanism underlying the effect is an enhanced sense of entitlement among competition winners.

Now I understand why, with each election, corruption grows.

PNAS 113  (7): 1754–1759 (2016)      doi/10.1073/pnas.1515102113