Rats and mice
edyong | July 8, 2009It's 1964, and a group of Canadian scientists had sailed across the Pacific to Easter Island in order to study the health of the isolated local population. Working below the gaze of the island's famous statues, they collected a variety of soil samples and other biological material, unaware that one of these would yield an unexpected treasure. It contained a bacterium that secreted a new antibiotic, one that proved to be a potent anti-fungal chemical. The compound was named rapamycin after the traditional name of its island source - Rapa Nui.
Skip forward 35 years and rapamycin has made a…
edyong | March 10, 2009If you wanted to turn a rat into a fearless critter, unfazed by cats or bigger rats, the best way would be to neutralise a small pair of tiny structures in its brain called the dorsal premammillary nuclei, orPMD. According to new research by Simone Motta at the University of Sao Paolo, these small regions, nestled within a rat's hypothalamus, control its defensive instincts to both predators and other rats.
But not all neurons in the PMD are equal. It turns out that the structures are partitioned so that different bits respond to different threats. The front and side parts (the ventrolateral…
edyong | January 18, 2009
You swallow the pill. As it works its way through your digestive system, it slowly releases its chemical payload, which travels through your bloodstream to your brain. A biochemical chain reaction begins. Old disused nerve cells spring into action and form new connections with each other. And amazingly, lost memories start to flood back.
The idea of a pill for memory loss sounds like pure science-fiction. But scientists from the Massachussetts Institute for Technology have taken a first important step to making it a reality, at least for mice.
Andre Fischer and colleagues managed to restore…
edyong | November 29, 2008
As Charles Darwin learned several centuries ago, islands are havens for evolution. Newcomers to these isolated worlds find themselves unshackled from the predators that dogged them on the mainland. They celebrate their freedom by diversifying into a great variety of species. But predators still have ways of tracking them down, and following the footsteps of sailors is one of them. By killing adults and eating eggs, introduced predators such as rats, cats and stoats are responsible for nine in ten of the bird extinctions since 1600.
Now, conservation agencies are getting serious about…
edyong | October 25, 2008
Animals often show a keen intelligence and many species, from octopuses to crows, can perform problem-solving tasks. But humans are thought to go one step further. We can reflect on our own thoughts and we have knowledge about our knowledge. We can not only solve problems, but we know in advance if we can (or are likely to).
In technical terms, this ability is known as 'metacognition'. It's what students do when they predict how well they will do in an exam when they see the questions. It's what builders do when they work out how long a job will take them to finish. But can animals do…
edyong | September 15, 2008We like to idolise fearlessness and we equate it to bravery but there is a fine line between that and stupidity. Immunity to the pangs of fear would leave someone unable to assess threats to themselves and to other people, which means that fear not only has consequences for an individual but for their entire social circle. Guillaume Martel and colleagues from Rutgers University demonstrated these far-reaching consequences by examining a special group of mice which had been genetically engineered to be fearless.
Martel's team focused their attention on the amygdalae, a pair of almond-shaped…
edyong | July 16, 2008Many measures to curb the obesity epidemic are aimed at young children. It's a sensible strategy - we know that overweight children have a good chance of becoming overweight adults. Family homes and schools have accordingly become critical arenas where the battle against the nation's growing waistlines is fought. But there is another equally important environment that can severely affect a person's chances of becoming overweight, but is more often overlooked - the womb.
Overweight parents tend to raise overweight children but over the last few years, studies have confirmed that this…
edyong | May 9, 2008
This week's New Scientist includes a short piece from me about conformist rats.
Until now, only humans and chimps were known to succumb to peer pressure, to the extent that we often ignore our own experiences based on the preferences of others. But a new study in brown rats shows that these rodents are similarly prone to following the Joneses. They can even be persuaded to choose a piece of food that they know makes them sick if they smell it on the breath of a 'demonstrator' rat.
Bennett Galef and Elaine Whiskin at McMaster University in Hamilton, Ontaria, Canada, trained rats to avoid…
edyong | February 25, 2008Humans have explored the entire face of the planet, but we haven't done so alone. Animals and plants came along for the ride, some as passengers and other as stowaways. Today, these hitchhikers pose one of the greatest threats to the planet's biodiversity, by ousting and outcompeting local species.
Islands are particularly vulnerable to invaders. Cut off from the mainland, island-dwellers often evolve in the absence of predators and competitors, and are prone to developing traits that make them easy pickings for invaders, like docile natures or flightlessness.
Two years ago, I wrote about…