Scientists have identified a way in which the brain's ability to process information diminishes with age, and shown that this break down contributes to the decreased ability to form memories that is associated with normal aging.
The finding, reported in the current online early edition of Proceedings of the National Academy of Sciences, fuels the researchers' efforts, they say, to explore strategies for enhancing brain function in the healthy aging population, through mental training exercises and pharmaceutical treatments.
The research, conducted by University of California, San Francisco and University of California, Berkeley scientists, builds on the team's seminal 2005 discovery ("Nature Neuroscience," October 2005) that the brain's capacity to ignore irrelevant information diminishes with age.
The capacity to ignore irrelevant information -- such as most of the faces in a crowded room when one is looking for a long-lost friend and to enhance pertinent information -- such as the face of a new acquaintance met during the search for the old friend is key to memory formation. This process is known as top-down modulation.
In the 2005 study, the team recorded brain activity in younger and older adults given a visual memory test in which they were shown sequences of images (sets of two faces and two scenes), told to remember a specific category, and then asked to identify an image from that category nine seconds later. The scientists, using functional magnetic resonance imaging (fMRI), determined that the neurons of the older participants (ages 60 to 72) responded excessively to the images they should have ignored, compared to the younger adults (ages 19 to 33). This attention to the distracting information directly correlated with how well the participants did on the memory test.
In the current study, the team used electroencephalography (EEG), which measures the speed of neural processing, to examine t
|Contact: Jennifer O'Brien|
University of California - San Francisco