Monday, June 20, 2011

Negative Emotion May Improve Memory

Picture a menacing drill sergeant, a gory slaughterhouse, a devastating scene of a natural disaster. Researchers at Washington University in St. Louis have found that viewing such emotion-laden images immediately after taking a test actually enhances people's retention of the tested material.

The data the researchers gathered in recent studies are the first to show that negative arousal following successful retrieval of information enhances later recall of that information.

The finding is counterintuitive. One would think that viewing a negative scene would tend to blot out anything learned before seeing the image.

Instead, learning is enhanced by the (negative) emotion, says Bridgid Finn, PhD, postdoctoral researcher in psychology in Arts & Sciences. "Memory is labile and dynamic -- after you retrieve something, you're still engaged in processing that information in some way," Finn says.

"Having a picture of a gun pointed at you just after you've just been tested on something probably isn't the best situation for learning, but because there is an intricate relationship between areas involved in emotion and remembering, the amygdala and the hippocampus, we find that the negative picture can enhance later retention."

Finn and Henry L. Roediger III, PhD, James S. McDonnell Distinguished University Professor and dean of academic planning, published their findings in the June 2011 issue of Psychological Science.

The researchers tested 40 undergraduate WUSTL students who studied ten lists of ten pairs of Swahili-English vocabulary items (lulu/pearl; ubini/forgery). Participants were given a cued recall test after studying each set of ten pairs, and then given a final test on all 100 pairs.

On the initial test, following each correct answer, they were shown a picture either of a negative emotional image such as a pointed gun; a neutral image, such as a chair, or a blank screen.
They then did a one-minute multiplication test, a sort of mental palette cleansing to remove the effects of short-term memory, like a serving of sherbet in a multiple course meal.

A final cued-recall test on all 100 Swahili-English items revealed that participants did best on items that had been followed by the negative pictures.

This initial experiment showed that the process involved in retrieving an item does not end when that item is retrieved. In a second experiment designed to explore the limits of the enhancement effect, the researchers tested a second group of students who viewed the images two seconds after successful retrieval. The question: Does the retrieval process persist during those two seconds?

"The answer appears to be yes, the students continue to process the information during the two second pause," Finn says.

A third study of 61 students was intended to rule out the possibility that arousing images simply made certain pairs of words seem more distinct, and thus made them easier to remember. This experiment was very similar to the other two with one major distinction: Instead of taking the initial tests, participants restudied the items.

"For negative emotion to enhance later retention of something, this experiment shows that you have to retrieve that information," Finn says. "That is, you have to go get it. In the absence of retrieval, the negative pictures do not enhance later performance. That's critical."

The study revealed no gender differences in participants' success rates. Finn and Roediger did not measure the effects of physiological parameters such as adrenaline or hormonal responses in connection with the negative arousal.

Importantly, other studies Finn and Roediger are doing thus far show that positive images do not enhance retrieval or retention. For instance, preliminary data on a study of participants who were tested on items that were followed by sexually arousing images show no learning enhancement. While the pictures were arousing, they weren't linked to enhanced retrieval on the later test.

"Positive content, so far, doesn't seem to be doing the trick," Finn says.

The researchers believe that their results mark the first step in understanding the kinds of things that might be beneficial to enhance memory after retrieval.

"We've established that the period after retrieval is key in retaining information," Finn says. "We want to build on that foundation and explore it in depth. We want to see what kinds of manipulations can possibly be introduced in the post-retrieval phase to understand when enhancement or impairment of retention might occur."


Monday, June 6, 2011

First man ‘functionally cured’ of HIV

Since HIV was discovered 30 years ago this week, 30 million people have died from the disease, and it prolongs to spread at the rate of 7,000 people per day globally, the UN says.

There's not much good news when it comes to this disturbing virus. But that is perhaps why the story of the man scientists call the "Berlin patient" is so extraordinary and has generated so much thrilled among the HIV support community.

Timothy Ray Brown suffered from both leukemia and HIV when he received a bone marrow stem cell transplant in Berlin, Germany in 2007. The transplant came from a man who was immune to HIV, which scientists say about 1 percent of Caucasians are.

What happened next has stunned the dozens of scientists who are closely monitoring Brown: His HIV went away.

"He has no replicating virus and he isn't taking any medication. And he will now probably never have any problems with HIV," his doctor Gero Huetter told Reporters. Brown now lives in the Bay Area, and suffers from some mild neurological difficulties after the operation. "It makes me very happy," he says of the incredible cure.

The development of anti-retroviral drugs in the 1990s was the first sign of hope in the epidemic, transforming the disease from a sudden killer to a more convenient illness that could be lived with for decades. But still, the amazing cocktail of drugs is expensive, costing $13 billion a year in developing countries alone. That figure is expected to triple in 20 years--raising the worry that more sick people will not be able to pay for the treatment.

Although Brown's story is extraordinary, scientists were quick to point out that bone marrow transplants can be fatal, and there's no way Brown's treatment could be applied to the 33.3 million people around the world living with HIV. The discovery does give confidence "cure research," according to Dr. Jay Levy, who co-discovered HIV thirty years ago, something that many people did not even think was possible years ago.

Sunday, June 5, 2011

Protein from Bones of 600,000-Year-Old Mammoth Extracted Effectively

Researchers from the University of York and Manchester have successfully extracted protein from the bones of a 600,000-year-old mammoth, paving the way for the recognition of ancient fossils.

Using an ultra-high resolution mass spectrometer, bio-archaeologists were able to create a near complete collagen series for the West Runton Elephant, a Steppe Mammoth skeleton which was discovered in cliffs in Norfolk in 1990. The remarkable 85 per cent complete skeleton -- the most total example of its species ever found in the world -- is potted by Norfolk Museums and Archaeology Service in Norwich.

Bio-archaeologist Professor Matthew Collins, from the University of York's Department of Archaeology, said: "The time depth is totally extraordinary. Until several years ago we did not believe we would find any collagen in a skeleton of this age, even if it was as well-preserved as the West Runton Elephant.

"We consider protein lasts in a useful form ten times as long as DNA which is normally only useful in detections of up to 100,000 years old in Northern Europe. The implications are that we can use collagen sequencing to look at very old extinct animals. It also means we can look through old sites and recognize remains from tiny fragments of bone."

Dr Mike Buckley, from the Faculty of Life Sciences at the University of Manchester, said: "What is truly charming is that this basically important protein, which is one of the most abundant proteins in most (vertebrate) animals, is an ideal target for obtaining long lost genetic information."

The collagen sequencing was carried out at the Centre for Excellence in Mass Spectrometry at the University of York and is debatably the oldest protein ever sequenced; short peptides (chains of amino acids) have controversially been accounted from dinosaur fossils.

The research formed part of a study into the sequencing of mammoths and mastodons, which is published in the journal Geochimica et Cosmochimica Acta. The West Runton Elephant was compared with other mammoths, modern elephants and mastodons. Despite the age of the fossil, sufficient peptides were obtained to recognize the West Runton skeleton as elephantid, and there was sufficient sequence variation to distinguish elephantid and mammutid collagen.

Nigel Larkin, co-author and Research Associate with Norfolk Museums and Archaeology Service, said: "The West Runton Elephant is unusual in that it is a nearly total skeleton. At the time this animal was alive, before the Ice Ages, spotted hyenas much larger than those in Africa today were scavenging most carcasses and eat greedily the bones as well as meat. That means most fossils found from this time period are individual bones or fragments of bone, making them difficult to identify. In the future, collagen sequencing might help us to decide the species represented by even smallest scraps of bone.

"Therefore this research has important insinuation for bones and bone fragments in all archaeological and palaeontological collections in museums and archaeology units around the world, not just those of Norfolk Museums and Archaeology Service in Norwich."