Science News Digest - 31st January 2012
In the science news this week, pythons are destroying the mammal population in Florida, scientists create brain cells from skin samples, smells trigger the most powerful memories, and finally… finding objects right in front of you could be hindered by out of sync brains.
Pythons are killing off Everglades mammals
Non-native pythons are the most likely cause for a rapid decline in mammal numbers in the Florida Everglades, according to a study published in the PNAS journal last week.
The Burmese pythons have flourished in the Everglades habitat due to its abundance of prey and warm climate. The origin of the pythons is unknown, but it is suspected that the rise in snake numbers stems from just a few animals that were released into the wild by private owners.
Reported on the BBC news website, the study compared the numbers of mammals, such as rabbits and raccoons, from before and after the increase in python numbers.
The pythons are now established over thousands of square kilometres in Southern Florida, and have become the new top predator. There have been reports of pythons eating alligators, the native top predator in the Everglades, a disturbing indicator of the size and strength of the snakes.
The study has been conducted by Professor Michael Dorcas from Davidson College in North Carolina, who looked at the data on mammal numbers found during roadkill surveys from 1993-99 and on encounters with live and dead mammals during nighttime road surveys during 1996-97.
The data was then compared to a similar set collected between 2003 and 2011, which was after the pythons became recognised as an established species.
The observations of raccoons and opossums dropped by a staggering 99 per cent, and there was a 94.1 per cent drop in white-tailed deer numbers.
Also, there were no sightings of foxes or rabbits in the most recent survey, yet rabbits were among the most common in the roadkill survey between 1993 and 1999.
Many of these species have become the regular diet of the Burmese pythons in the Everglades National Park, partly because they become easy prey when foraging on the waters’ edge, a place the pythons can ambush from.
The decline in mammal numbers coincides with the geographical spread of the pythons.
Professor Dorcas said to the BBC that more research was needed in order to assess the impact of such large declines. But he added: "It's not unreasonable to assume that any time we have major declines in mammals like this it's going to have overall impacts on the ecosystem. Exactly what those are going to be, we don't know. But it's possible they could be fairly profound."
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Scientists create brain cells using skin samples
Scientists from the Centre of Regenerative Medicine in Edinburgh have created brain cells using samples of skin from patients suffering from schizophrenia, bipolar depression and other mental illnesses.
In a series of experiments, the team managed to create neurones genetically identical to those in that person's brain. The implications of these experiments could be profound, explains The Guardian, as it allows scientists to study the neurological effects these conditions have at a cellular level.
"A patient's neurones can tell us a great deal about the psychological conditions that affect them, but you cannot stick a needle in someone's brain and take out its cells," said Professor Charles ffrench-Constant, the centre's director.
"However, we have found a way round that. We can take a skin sample, make stem cells from it and then direct these stem cells to grow into brain cells. Essentially, we are turning a person's skin cells into brain. We are making cells that were previously inaccessible. And we could do that in future for the liver, the heart and other organs on which it is very difficult to carry out biopsies."
The project focussed on the neurones of patients suffering from mental illness and is directed by Professor Andrew McIntosh of the Royal Edinburgh Hospital, who is collaborating with the regenerative medicine centre.
"We are making different types of brain cells out of skin samples from people with schizophrenia and bipolar depression," he said. "Once we have assembled these, we look at standard psychological medicines, such as lithium, to see how they affect these cells in the laboratory. After that, we can start to screen new medicines. Our lines of brain cells would become testing platforms for new drugs. We should be able to start that work in a couple of years."
As well as looking at mental illness, the centre has also been concentrating on a range of neurological conditions, including multiple sclerosis, Parkinson’s disease and motor neurone disease.
In the past, scientists have studied brain tissue from people with conditions such as schizophrenia, but could only do so once an autopsy had been carried out. "It is very difficult to get primary tissue to study until after a patient has died," added McIntosh.
"Even then, that tissue is affected by whatever killed them and by the impact of the medication they had been taking for their condition, possibly for several decades. So having access to living brain cells is a significant development for the development of drugs for these conditions."
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Smells can trigger powerful memories more often than sounds
A team of scientists from Utrecht University in The Netherlands have shown that smells trigger more detailed, arousing and unpleasant memories of painful experiences than sounds do. Reported in The Telegraph, the researchers recruited 70 female students and played them disturbing video footage, which was designed to provoke aversion, for example car accidents or reports on the Rwandan genocide.
During the film, the scientists pumped the smell of cassis into the room, switched on coloured lights and played neutral music.
A week later, the participants were asked to recall their memories of the film whilst being exposed to the smell of cassis, the lights or the music from the screening.
The researchers found that those exposed to the smell a week later were able to recall more details about the film than those who were played the music.
However, the team also found the lights were also effective in getting the participants to recall the details of the film.
This research could prove useful in the research of post-traumatic stress disorder, and go some way to explaining the Proust phenomenon, the idea that distinctive smells have more power than any other sense to help us recall distant memories.
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And finally…
An out-of-sync mind could make it tricky to find things
Have you ever lost your keys only to realise you’re holding them in your hand? Well, new research reported in New Scientist this week has revealed that this could be because the brain systems involved are working at different speeds, with the perception system unable to keep pace.
Grayden Solman and his colleagues at the University of Waterloo in Ontario, Canada, created a simple computer task that involved searching through coloured shapes on the screen. The volunteers had to find a specific shape as quickly as possible and the computer monitored their actions.
"Between 10 and 20 per cent of the time, they would miss the object," says Solman, even though they picked it up. "We thought that was remarkably often."
The team created a number of other experiments to then investigate whether it was due to the participant forgetting their target, or whether it was because they weren’t paying enough attention to the items they were moving.
It seems that the participants’ movements were slower after they had missed their target, which suggests that on some level they were aware that they had missed their target, even if they didn’t consciously realise they had made a mistake.
Pythons are killing off Everglades mammals
Non-native pythons are the most likely cause for a rapid decline in mammal numbers in the Florida Everglades, according to a study published in the PNAS journal last week.
The Burmese pythons have flourished in the Everglades habitat due to its abundance of prey and warm climate. The origin of the pythons is unknown, but it is suspected that the rise in snake numbers stems from just a few animals that were released into the wild by private owners.
Reported on the BBC news website, the study compared the numbers of mammals, such as rabbits and raccoons, from before and after the increase in python numbers.
The pythons are now established over thousands of square kilometres in Southern Florida, and have become the new top predator. There have been reports of pythons eating alligators, the native top predator in the Everglades, a disturbing indicator of the size and strength of the snakes.
The study has been conducted by Professor Michael Dorcas from Davidson College in North Carolina, who looked at the data on mammal numbers found during roadkill surveys from 1993-99 and on encounters with live and dead mammals during nighttime road surveys during 1996-97.
The data was then compared to a similar set collected between 2003 and 2011, which was after the pythons became recognised as an established species.
The observations of raccoons and opossums dropped by a staggering 99 per cent, and there was a 94.1 per cent drop in white-tailed deer numbers.
Also, there were no sightings of foxes or rabbits in the most recent survey, yet rabbits were among the most common in the roadkill survey between 1993 and 1999.
Many of these species have become the regular diet of the Burmese pythons in the Everglades National Park, partly because they become easy prey when foraging on the waters’ edge, a place the pythons can ambush from.
The decline in mammal numbers coincides with the geographical spread of the pythons.
Professor Dorcas said to the BBC that more research was needed in order to assess the impact of such large declines. But he added: "It's not unreasonable to assume that any time we have major declines in mammals like this it's going to have overall impacts on the ecosystem. Exactly what those are going to be, we don't know. But it's possible they could be fairly profound."
-------------------------------------------------
Scientists create brain cells using skin samples
Scientists from the Centre of Regenerative Medicine in Edinburgh have created brain cells using samples of skin from patients suffering from schizophrenia, bipolar depression and other mental illnesses.
In a series of experiments, the team managed to create neurones genetically identical to those in that person's brain. The implications of these experiments could be profound, explains The Guardian, as it allows scientists to study the neurological effects these conditions have at a cellular level.
"A patient's neurones can tell us a great deal about the psychological conditions that affect them, but you cannot stick a needle in someone's brain and take out its cells," said Professor Charles ffrench-Constant, the centre's director.
"However, we have found a way round that. We can take a skin sample, make stem cells from it and then direct these stem cells to grow into brain cells. Essentially, we are turning a person's skin cells into brain. We are making cells that were previously inaccessible. And we could do that in future for the liver, the heart and other organs on which it is very difficult to carry out biopsies."
The project focussed on the neurones of patients suffering from mental illness and is directed by Professor Andrew McIntosh of the Royal Edinburgh Hospital, who is collaborating with the regenerative medicine centre.
"We are making different types of brain cells out of skin samples from people with schizophrenia and bipolar depression," he said. "Once we have assembled these, we look at standard psychological medicines, such as lithium, to see how they affect these cells in the laboratory. After that, we can start to screen new medicines. Our lines of brain cells would become testing platforms for new drugs. We should be able to start that work in a couple of years."
As well as looking at mental illness, the centre has also been concentrating on a range of neurological conditions, including multiple sclerosis, Parkinson’s disease and motor neurone disease.
In the past, scientists have studied brain tissue from people with conditions such as schizophrenia, but could only do so once an autopsy had been carried out. "It is very difficult to get primary tissue to study until after a patient has died," added McIntosh.
"Even then, that tissue is affected by whatever killed them and by the impact of the medication they had been taking for their condition, possibly for several decades. So having access to living brain cells is a significant development for the development of drugs for these conditions."
-----------------------------------------------------
Smells can trigger powerful memories more often than sounds
A team of scientists from Utrecht University in The Netherlands have shown that smells trigger more detailed, arousing and unpleasant memories of painful experiences than sounds do. Reported in The Telegraph, the researchers recruited 70 female students and played them disturbing video footage, which was designed to provoke aversion, for example car accidents or reports on the Rwandan genocide.
During the film, the scientists pumped the smell of cassis into the room, switched on coloured lights and played neutral music.
A week later, the participants were asked to recall their memories of the film whilst being exposed to the smell of cassis, the lights or the music from the screening.
The researchers found that those exposed to the smell a week later were able to recall more details about the film than those who were played the music.
However, the team also found the lights were also effective in getting the participants to recall the details of the film.
This research could prove useful in the research of post-traumatic stress disorder, and go some way to explaining the Proust phenomenon, the idea that distinctive smells have more power than any other sense to help us recall distant memories.
------------------------------------
And finally…
An out-of-sync mind could make it tricky to find things
Have you ever lost your keys only to realise you’re holding them in your hand? Well, new research reported in New Scientist this week has revealed that this could be because the brain systems involved are working at different speeds, with the perception system unable to keep pace.
Grayden Solman and his colleagues at the University of Waterloo in Ontario, Canada, created a simple computer task that involved searching through coloured shapes on the screen. The volunteers had to find a specific shape as quickly as possible and the computer monitored their actions.
"Between 10 and 20 per cent of the time, they would miss the object," says Solman, even though they picked it up. "We thought that was remarkably often."
The team created a number of other experiments to then investigate whether it was due to the participant forgetting their target, or whether it was because they weren’t paying enough attention to the items they were moving.
It seems that the participants’ movements were slower after they had missed their target, which suggests that on some level they were aware that they had missed their target, even if they didn’t consciously realise they had made a mistake.
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