Which brain processes enable humans to rapidly access their personal knowledge? What happens if humans perceive either familiar or unfamiliar objects?

The answer to these questions may lie in the direction of information flow transmitted between specialized brain areas that together establish a dynamic cortical network.

Fruit or vegetable, insect or bird, familiar or unfamiliar – humans are used to classify objects in the world around them and group them into categories that have been formed and shaped constantly through every day's experience. Categorization during visual perception is exceptionally fast.

A team of scientists led by professor Kiminobu Sugaya at the University of Central Florida may have found a new way to treat Alzheimer’s disease.

The team, which also included researchers from the Karolinska Institute in Sweden and the National Institutes of Health, combined a technique for transplanting stem cells into rats and a newly discovered compound, phenserine. It reduces the amount of a plaque that is a hallmark of Alzheimer’s disease. The combination triggered the regeneration of neurons that are destroyed by Alzheimer’s and are necessary for healthy brain functions.

There are 5 million Americans living with Alzheimer’s, one of the most common forms of dementia, according to the National Alzheimer’s Association.

In the past ten years, researchers in genome stability have observed that many kinds of cancer are associated with areas where human chromosomes break. They have hypothesized – but never proven – that slow or altered replication led to the chromosomes breaking.

In a Tufts University study, two molecular biologists have used yeast artificial chromosomes to prove the hypothesis. They have found a highly flexible DNA sequence that increases fragility and stalls replication, which then causes the chromosome to break.

Catherine Freudenreich, associate professor of biology at Tufts University, and doctoral student Haihua Zhang focused on one particular human common fragile site – an area that is a normal part of chromosome structure but is prone to breaking.

The causes of depression have not been fully identified but scientists acknowledge that genetic and environmental factors play a role in the onset of the disorder. One of the environmental risk factors more often related to depression is exposure to threatening life events. From a genetic point of view, the serotonin transporter gene, with its crucial role in communication between neurons, could also predispose people to depression.

An international group of scientists, headed by professors Jorge Cervilla Ballesteros and Blanca Gutiérrez Martínez, from University of Granada, has recently published the study PREDICT-gene, confirming the relationship between alleles in the serotonin transporter gene and exposure to threatening life events in the onset of depression.

The new planet was identified by astronomers looking for transiting planets – that is, planets that pass in front of their home star – using a network of small automated telescopes in Arizona, California, and the Canary Islands. TrES-4 was discovered less than half a degree (about the size of the full Moon) from the team’s third planet, TrES-3.

"TrES-4 is the largest known exoplanet," said Georgi Mandushev, Lowell Observatory astronomer and the lead author of the paper announcing the discovery. "It is about 70 percent bigger than Jupiter, the Solar System’s largest planet, but less massive, making it a planet of extremely low density. Its mean density is only about 0.2 grams per cubic centimeter, or about the density of balsa wood!

A new study reveals correlations between plentiful sunspots and periods of heavy rain in East Africa. Intense rainfall in the region often leads to flooding and disease outbreaks.

The analysis by a team of U.S. and British researchers shows that unusually heavy rainfalls in East Africa over the past century preceded peak sunspot activity by about one year. Because periods of peak sunspot activity, known as solar maxima, are predictable, so too are the associated heavy rains that precede them, the researchers propose.

“With the help of these findings, we can now say when especially rainy seasons are likely to occur, several years in advance," says paleoclimatologist and study leader Curt Stager of Paul Smith's College in Paul Smiths, New York.