The sensory and perceptual mechanisms of the human brain can be reconfigured
so as to optimize the processing of a selected type or class of information (i.e. frequency,
location, etc.). A foundational goal of cognitive neuroscience is to pursue an
understanding of the neural processes that underlie this reconfiguration. Auditory
selective attention has been the topic of considerable investigation, principally by the use
of event-related potential (ERP) techniques to record certain electrophysiological
correlates of attentional selection. The large majority of this work has focused on a
single paradigm, known as the sustained-attention paradigm, in which listeners
continuously focus their attention at a particular location or on a particular frequency of
sound. Only a very few previous studies have investigated the more realistic situation in
which listeners continuously reorient their attention on a moment-by-moment basis. This
thesis reports the systematic investigation of transient auditory attention. The ERP
technique was used to address questions regarding the neural correlates and functional
anatomy of auditory selective attention in a variety of situations in which attention was
continuously reoriented in space. Following a brief introduction and review in Chapter
One, Chapter Two reports the result of the first high-density (64-electrode) study of the
ERP correlates of transient spatial auditory attention. This chapter concludes with the
speculation that transient attention modulates neurons within a dedicated spatial
processing or "where" pathway that projects posteriorly and dorsally from auditory
cortex. Chapter Three checks the assumptions of this hypothesis by identifying an ERP
correlate of spatial processing and localizing the generator of this correlate to a region of
cortex believed to constitute part of this "where" pathway. Finally, Chapter Four reports
the results of several experiments that localized certain attention-related modulations of
the ERP to this putative "where" pathway. These experiments also demonstrated that
transient auditory attention involves a complex interaction between stimulus-driven and
goal-driven (bottom-up and top-down) processes that lead to distinctly different patterns
of ERP activity. The thesis concludes with a discussion of the advancements made,
relative to the state of previous knowledge, as a result of the work presented here.Medicine, Faculty ofGraduat