Working memory refers to the retention of information in conscious awareness when this information is not present in the environment, to its manipulation, and to its use in guiding behavior. Working memory has been implicated as a critical contributor to such essential cognitive functions and properties as language comprehension, learning, planning, reasoning, and general fluid intelligence. Additionally, individual differences in working memory performance predict a remarkable array of "real world" outcome measures, from reading ability to standardized test performance to socioeconomic status to personality traits. Thus, understanding the cognitive and neural bases of working memory functions is central to understanding normal cognition, as well as its neurological and psychiatric dysfunctions. The PI's research program investigates the cognitive and neural bases of working memory function. It does so within a framework that holds that working memory is an emergent property that arises from the coordinated recruitment, via attention, of brain systems that have evolved to accomplish sensory-, representation-, or action-related functions. The Specific Aims of the present application for renewal of the PI's R01 build on this work by articulating hypotheses than will support stronger inference than could those proposed in 2003 (due to the addition of novel multivariate methods for measuring functional connectivity and of repetitive transcranial magnetic stimulation (rTMS) to the PI's methodological armamentarium), and by testing mechanistic hypotheses that have arisen from the PI's recent work. They are: Specific Aim 1: To test the hypothesis that working memory storage is supported by broadly distributed, functionally connected networks of regions posterior to the PFC. Specific Aim 2: To test the hypothesis that working memory storage is accomplished, in part, via the temporary activation of long-term memory (LTM) representations. Specific Aim 3: To test the hypothesis that the frontal eye fields (FEF) are a source of the attentional activation that supports working memory storage. PUBLIC HEALTH RELEVANCE Impairments of working memory are seen in many neurological, psychiatric, and developmental disorders. Achieving a better understanding of the cognitive and neurobiological organization of working memory functions, therefore, may have important implications for the diagnosis, clinical treatment, and cognitive rehabilitation of patients with these disorders.