The Functional Neuroanatomy Of Memory Systems In The Human Brain

National Institute Of Mental Health

Investigators

Linked publications, trials & patents

Abstract

During the past year we have continued to focus on two main themes concerning the functional neuroanatomy of memory. The first theme concerns semantic memory, the part of long-term memory composed of general information, such as facts, ideas, and the meaning of objects and words. We are particularly interested in characterizing the neural substrate mediating object and word meaning and its role in object perception. We are also interested in understanding how abstract knowledge, such as information about social interactions, is represented. Our studies have shown that information about salient properties of an object - such as what it looks like, how it moves, and how it is used - is stored in the sensory and motor systems active when objects are perceived and manipulated. As a result, objects belonging to different categories such as animate entities (people, animals) and manmade manipulable objects (tools, utensils) are represented in partially distinct neural circuits. These circuits may also underpin our ability to understand more abstract events such as social and mechanical interactions. Building on these findings, investigations are underway to evaluate the integrity of these neural circuits in subjects with development disorders of social understanding and communication (autism spectrum disorders).[unreadable] [unreadable] The second theme focuses on an implicit or non-conscious memory phenomenon - repetition priming - as a model system for evaluating learning and neural plasticity. Our investigations show that this powerful form of learning is extremely long lasting and impervious to aging. We are also investigating the neural mechanism underpinning this form of learning - referred to as repetition suppression in pre- and post-operative studies of patients who have undergone surgical removal of the anterior regions of the left or right temporal lobe for the relief of intractable epilepsy. Our preliminary findings suggest that repetition suppression is dependent on signals originating from more anterior regions of temporal and/or frontal lobes.