Neural Systems for Representation of Item and Relations in Working Memory

Johns Hopkins University, Baltimore MD

Investigators

Abstract

In order to optimally guide our behavior according to flexible goals and novel situations, we must keep in mind relevant information that we cannot currently see, hear, or otherwise sense. This ability is called "working memory" and it forms the basis of most of our higher cognitive functions. Working memory appears to depend, in part, on a large part of the brain called the frontal cortex. It is unknown, however, what role the frontal cortex plays in working memory, how it is anatomically organized, or the neural mechanisms that underlie its functions. One theory is that the posterior part of frontal cortex maintains relevant information through interactions with other parts of the brain that process and represent sensory information and that the rest of the frontal cortex is organized according to different types of computational processes that act on that information. An alternative theory, proposed by Dr. Susan Courtney-Faruqee of Johns Hopkins University, is that all regions of the frontal cortex represent currently relevant information in sustained patterns of neural activity. This theory posits that the neural mechanisms of all frontal areas are qualitatively similar, that each area represents a different type of information, and that computational processes and influences on behavior occur through hierarchically organized interactions among these information representations. With funding from the National Science Foundation, Dr. Courtney-Faruqee and colleagues will use functional magnetic resonance imaging in healthy human volunteers to measure changes in neural activity while the volunteers try to remember different kinds of information, testing whether remembering abstract relational information results in similar patterns of activity in anterior frontal cortex as remembering individual items does in posterior frontal cortex. The research team will also collect saliva samples from those volunteers, which will be tested for normal genetic variations that are known to affect the function of prefrontal cortex. Dr. Courtney-Faruqee will test whether such normal genetic variation equally affects the neural activity underlying working memory for different types of information across different regions of frontal cortex. Such a result would suggest that similar neural mechanisms are at work across these distinct regions and that their specialized roles in various cognitive tasks are the result of different interactions with other brain areas rather than a qualitative difference in neural processes within each brain area. This research will shed light on the way the brain enables our most complex patterns of thought and our ability to flexibly shape our future behavior according to previously learned information and current goals. The research will also provide information about how normal variation in our genes affects these abilities. This information would help direct medical research into causes and treatments of disease and injury that affects these mental abilities. It could also shape education methodology based on individual strengths and weaknesses in information processing and memory. While advancing this fundamental knowledge regarding human abilities in controlling goal directed behavior, the research will also serve to train a new, diverse generation of interdisciplinary scientists.