Thanks for the memory. In everyday life old memories can interfere with newer memories — a phenomenon psychologists call proactive interference. It is harder, for example, to remember where we parked the car when we leave it in a different location in the same parking lot every day.

Recently, a team of scientists at the Center for Memory and the Brain, led by research associate Alireza Atri, Chantal Stern, a CAS associate professor of psychology, and Michael Hasselmo, a CAS psychology professor, published a new study demonstrating the role of acetylcholine, an important neurotransmitter in the brain, in preventing proactive interference with new learning. The study also sheds light on how cholinesterase inhibitors, which are FDA-approved drugs that slow the breakdown of acetylcholine, may alleviate symptoms of dementia in people with Alzheimer’s and other diseases.

The researchers administered a common memory test — learning pairs of words — to 28 healthy young adults, some of whom were given scopolamine, a drug that blocks acetylcholine receptors in the brain. These subjects performed significantly poorer on memory tests for word pairs learned after the drug was administered than did subjects who did not receive the drug. The memory of the scopolamine group for word pairs learned before administration of the drug was not affected.

The memory impairment was stronger for word pairs that overlapped with previously presented word pairs, indicating that interference was enhanced by the drug. This supports the researchers’ theory that acetylcholine helps prevent interference during normal memory function, and that the progression of Alzheimer’s disease may be linked to loss of acetylcholine effects as well.

Low levels of acetylcholine are associated with Alzheimer’s disease, Parkinson’s disease, dementia from multiple strokes, schizophrenia, and multiple sclerosis. According to the researchers, understanding the effects of cholinesterase inhibitors on the major symptoms of these diseases as they progress may allow scientists to develop more targeted and effective drugs and avoid medications that may be detrimental to memory.

This study appears in the February issue of the journal Behavioral Neuroscience.

Early warning system. Research by a Boston University School of Medicine team led by Ramachandran Vasan, an associate professor of medicine, may help doctors quickly identify people at increased risk of developing potentially life-threatening heart disease and stroke well before symptoms appear. The researchers found that people with high levels of a protein named B-type natiuretic peptide (BNP) in their blood were at higher risk for cardiovascular problems. BNP dilates blood vessels to increase blood flow and lowers blood pressure. The researchers hypothesized that a failing or stressed heart may try to protect itself by secreting more and more of the peptide.

Vasan and his colleagues examined the medical records of 3,346 participants in the Framingham Offspring Study over a period of more than five years. They found that those with elevated levels of BNP in their blood were more likely to die or have a stroke, a cardiovascular event, heart failure, or an abnormal heartbeat, known as atrial fibrillation. This held true even after taking into account known risk factors such as age, sex, high blood pressure, smoking, diabetes, and elevated cholesterol.

A related study by researchers in Switzerland found that BNP measurements effectively identified patients with congestive heart failure among people who were admitted to the emergency room with acute breathing problems. By simplifying this otherwise difficult diagnosis, BNP testing may potentially save both lives and money.

“Many more studies are needed to determine the role of BNP in diagnosis and treatment of cardiovascular disease,” says Vasan. “We must see how well it does in comparison with, and in combination with, other biomarkers, such as C-reactive protein, a marker of inflammation also associated with cardiovascular risk. Perhaps this marker could give a warning about potential trouble in asymptomatic people.”

The work by the MED team was reported in the February 12 issue of the New England Journal of Medicine.