You enter a crowded room, searching for an old friend amongst a sea of unfamiliar faces and other distractions. You retrieve a stored representation of your friend’s face from memory, hold it in mind and compare it to the many faces before you. You scan your surroundings, making lightening fast decisions… and soon a match is made and you recognize your friend.  As you cross the room another person waves at you, capturing your attention. You signal that you will be right with them, and while storing this new information in mind, you proceed to make contact with your friend.

Our brains receive a constant onslaught of sensory information that demands a continuous integration between stimuli that capture our attention independent of our goals (e.g., the person waving you over) and our internal decisions as to where we direct our attention and what we store in memory (e.g. searching the room for your friend and remembering the new face). The focus of research in the Gazzaley lab is the neural process known as top-down modulation, which underlies our ability to exert conscious control over how we perceive our environment. It is this ability to selectively focus our attention, suppress distracting input and hold relevant information in mind that defines our conscious experience and serves as a critical crossroad between attention and memory. Furthermore, this phenomenon is not restricted to processing visual information in crowded situations, as illustrated above, but it occurs constantly and involves all of our senses. We would be incapable of functioning if we were unable to exert conscious control over our perceptual world. In fact, it is a breakdown of this system that leads to many of the functional difficulties experienced by individuals as they age, as well as those with dementia.