Narrator: This is Science Today. What exactly happens, on a fundamental level, as the human brain ages? Dr. Adam Gazzaley, director of the Neuroscience Imaging Center at the University of California, San Francisco has been trying to understand the basic changes, looking for a unifying principle of what occurs during the aging process.
Gazzaley: We found that there's a process known as top-down modulation by which you do not passively view the world. How you attend to the world is influenced by your attention, both the attention that the environment imposes upon you, if there's a flash of light or a loud sound that demands your attention, whether or not your goals were directed to it.
Narrator: The other type of attention is the goal-directed behavior - how one chooses to focus limited resources
Gazzaley: Their ability to do that really defines all cognitive ability. So this is why I was interested in studying this process. And what it serves is a sort of interface between top-down modulation and how that interacts with other cognitive abilities and how that translates to memory, either better memory or worse memory.
Narrator: For Science Today, I'm Larissa Branin.