Snails use 'two brain cells' to make decisions, Sussex University discovers

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Snails use two brain cells to make "complex decisions", a team of scientists has found.

Researchers at the University of Sussex said one cell told the snail if it was hungry while the other cell told it if food was present.

The experiments used electrodes to measure brain activity of the molluscs when searching for lettuce.

Lead researcher Prof George Kemenes said the discovery would help engineers design "robot brains".

He said these would be based on the principle of using the fewest possible components necessary to perform complex tasks.

"Our study reveals for the first time how just two neurons can create a mechanism in an animal's brain which drives and optimises complex decision-making tasks," he said.

"It also shows how this system helps to manage how much energy they use once they have made a decision.

"Our findings can help scientists to identify other core neuronal systems which underlie similar decision-making processes."

The study was published in the journal Nature Communications.

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Elephant society 'still disrupted decades after cull'

African elephants' decision-making abilities are left impaired by culling operations that ended decades ago, University of Sussex research suggests.

A study found that elephant herds that lost adults to culls during the 1970s and 1980s were less able to respond appropriately to other elephant calls.

Lead researcher Prof Karen McComb said the animals' "social understanding" had been impaired by the loss of adults.

The results are published in the journal Frontiers in Zoology.

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Hunger Affects Decision-Making and Perception of Risk

June 25, 2013 — Hungry people are often difficult to deal with. A good meal can affect more than our mood, it can also influence our willingness to take risks. This phenomenon is also apparent across a very diverse range of species in the animal kingdom. Experiments conducted on the fruit fly, Drosophila, by scientists at the Max Planck Institute of Neurobiology in Martinsried have shown that hunger not only modifies behaviour, but also changes pathways in the brain.

Animal behaviour is radically affected by the availability and amount of food. Studies prove that the willingness of many animals to take risks increases or declines depending on whether the animal is hungry or full. For example, a predator only hunts more dangerous prey when it is close to starvation. This behaviour has also been documented in humans in recent years: one study showed that hungry subjects took significantly more financial risks than their sated colleagues.

Also the fruit fly, Drosophila, changes its behaviour depending on its nutritional state. The animals usually perceive even low quantities of carbon dioxide to be a sign of danger and opt to take flight. However, rotting fruit and plants -- the flies' main sources of food -- also release carbon dioxide. Neurobiologists in Martinsried have now discovered how the brain deals with this constant conflict in deciding between a hazardous substance and a potential food source taking advantage of the fly as a great genetic model organism for circuit neuroscience.

In various experiments, the scientists presented the flies with environments containing carbon dioxide or a mix of carbon dioxide and the smell of food. It emerged that hungry flies overcame their aversion to carbon dioxide significantly faster than fed flies -- if there was a smell of food in the environment at the same time. Facing the prospect of food, hungry animals are therefore significantly more willing to take risks than sated flies. But how does the brain manage to decide between these options?

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