Subcortical Functions in Language and Memory

Book excerpt: How do the thalamus, basal ganglia, and basal forebrain participate in language and memory? Are these anatomic entities involved in regulation of cortical activity, complex information processing, transfer of information between cortical units, motivation, or in other functions? This volume is the first single-authored volume devoted to understanding how deep brain structures participate in language and memory. Addressing a relatively new area of research, the book is unique in two ways. First, it comprehensively covers both language and memory not only with extensive literature reviews, but also with examinations of the anatomy of the structures involved and discussions of theory in light of empirical data. Second, the book takes a systems approach to the topics. In order to produce and understand language or to record and retrieve memories, different parts of the brain must operate as integrated systems. As subcortical structures are parts of these systems, this book endeavors to understand how these phylogenetically older structures contribute to systems responsible for communication and mnestic functions. Designed to facilitate this end, each of the book's sections follows a neuroanatomy--empirical data--theory format. Part I concentrates on the participation (or nonparticipation) of various subcortical structures in language. Rather than attempt to arrive at definitive conclusions, these chapters explore the possibilities suggested by the currently available data. Following a description of the neuroanatomy and a discussion of the data concerning the thalamus and basal ganglia, attention is paid to theories regarding the participation of these structures in language. Part II addresses the thalamus, other diencephalic structures, the basal forebrain, and the basal ganglia regarding their possible roles in memory. The connections between these structures are addressed, as is the relationship between current data on the participation of subcortical structures in memory and current neuropsychological assumptions about memory. The extensive literature on memory in alcoholic Korsakoff's syndrome and Huntington's disease is culled for insights into what memory processes are subserved by subcortical structures, and memory theory is examined in light of what the subcortical literature reveals about memory. Paving the way for future research that holds the promise of a greater flexibility and complexity than now exists with purely cortical models, this volume will interest clinical and experimental neuropsychologists, cognitive psychologists, behavioral neurologists, speech/language pathologists, and psychiatrists with an interest in behavioral neurology. It also serves as a text for upper level graduate courses covering subcortical functions in cognition, neural systems, and advanced human neuropsychology.