Super User
From Different Corners
New York, March 17 (IANS) In the early stages of Alzheimer's disease, patients are often unable to remember recent experiences. However, a significant research suggests that those memories are still stored in the brain and can be retrieved with a new technique in the near future.
According to neuroscientists including an Indian-origin scientist from the Massachusetts Institute of Technology (MIT), mice in the early stages of Alzheimer's can form new memories just as well as normal mice but cannot recall them a few days later.Furthermore, the researchers were able to artificially stimulate those memories using a technique known as optogenetics, suggesting that those memories can still be retrieved with a little help. Although optogenetics cannot currently be used in humans, the findings raise the possibility of developing future treatments that might reverse some of the memory loss seen in early stage Alzheimer's.
“The important point is that this is a proof of concept. That is, even if a memory seems to be gone, it is still there. It's a matter of how to retrieve it,” said Susumu Tonegawa, director of the RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory.Tonegawa is the senior author of the study which appeared in the journal Nature, and Dheeraj Roy, an MIT graduate student, is the paper's lead author.
The researchers have also shown that they can manipulate these memory traces or engrams to plant false memories, activate existing memories, or alter a memory's emotional associations.To investigate this further, the researchers studied two different strains of mice genetically engineered to develop Alzheimer's symptoms along with a group of healthy mice.All of these mice, when exposed to a chamber where they received a foot shock, showed fear when placed in the same chamber an hour later. However, when placed in the chamber again several days later, only the normal mice still showed fear.
The Alzheimer's mice did not appear to remember the foot shock.
"Short-term memory seems to be normal, on the order of hours. But for long-term memory, these early Alzheimer's mice seem to be impaired," Roy said.
The researchers then showed that while the mice cannot recall their experiences when prompted by natural cues, those memories are still there.
“Directly activating the cells that we believe are holding the memory gets them to retrieve it," Roy noted, adding that “this suggests that it is indeed an access problem to the information, not that they're unable to learn or store this memory”.
“If we want to recall a memory, the memory-holding cells have to be reactivated by the correct cue. If the spine density does not go up during learning process, then later, if you give a natural recall cue, it may not be able to reach the nucleus of the engram cells," Tonegawa explained.
The researchers were also able to induce a longer-term reactivation of the "lost" memories by stimulating new connections between the entorhinal cortex region of the brain and the hippocampus.
“It's possible that in the future some technology will be developed to activate or inactivate cells deep inside the brain, like the hippocampus or entorhinal cortex, with more precision," Tonegawa added.
Super User
From Different Corners
London, March 15 (IANS) Traditionally viewed as a predator of insects, a new study has revealed that spiders like to spice up their menu occasionally with a vegetarian meal.The study showed evidence of spiders from ten families feeding on a wide variety of different plant types such as trees, shrubs, weeds, grasses, ferns or orchids. Also, these spiders demonstrated a diverse taste when it comes to the type of plant food: Nectar, plant sap, honeydew, leaf tissue, pollen and seeds are all on the menu.
As plant-dwelling, highly mobile foragers with excellent capability to detect suitable plant food, these spiders seems to be predestined to include some plant food in their diets.
Spiders diversifying their diet with plants are advantageous as it provides them with additional nutritional supplements and helps them survive when the insects are scarce, said the study detailed in the Journal of Arachnology.
"The ability of spiders to derive nutrients from plants is broadening the food base of these animals; this might be a survival mechanism helping spiders to stay alive during periods when insects are scarce," said study lead author Martin Nyffeler from University of Basel in Switzerland. However, the extent to which the different categories of plant food contribute to the spiders' diet is still largely unexplored.Although spiders feeding on plants are global in its extent, it is reported more frequently from warmer areas, the study said.The researchers suggested that it might be due to the fact that a larger number of the reports relate to nectar consumption, which has its core distribution in warmer areas where plants secreting large amounts of nectar are widespread.
Super User
From Different Corners
London, March 11 (IANS) It is often assumed that as our income rises so does our life satisfaction but this may not be the case with many people.
According to researchers, what really matters is when income is lost and this is only important for people who are highly conscientious, hard working and diligent.
The research, which examined levels of life satisfaction and income changes in more than 18,000 adults over a nine-year period, revealed that income change is only important when individuals with specific personality characteristics experience an income loss.
According to the team, continually increasing our income is not an important factor for achieving greater happiness and well-being for most people living in economically-developed countries.
"Instead, we should aim for financial stability to achieve greater happiness while protecting those individuals who experience negative income shocks," said Christopher Boyce of the behavioural science centre at the University of Stirling in Britain.
The study, involving two separate samples from Germany and Britain, asked participants annually about their income level and how satisfied they were with life.
Participants also answered questions on their personality at the start of the study.
Results revealed that regardless of personality, income increases did not affect life satisfaction.
When people lost income, however, there was a reduction in their life satisfaction.
This was far greater for those who reported themselves as being conscientious, namely they were thorough in their attitudes to life and work, energetic, effective and efficient in how they did things.
The study accounted for shifting circumstances such as entering or leaving work and changes to health and household make up.
It found that for people that were only even moderately conscientious, a loss of income had a negative impact at least two and a half times greater than less conscientious individuals.