Evidence for separable networks for auditory and visual attention

Abstract

The research reported in this thesis investigated the neural systems involved in auditory attention, and in particular how these may differ from those recruited for visual attention. One current leading theory of attentional control postulates that a single frontoparietal network (the ‘dorsal attention network’ or DAN) subserves top-down attention to all sensory modalities. However, there is an abundance of published evidence which contradicts this claim (which is discussed herein). This thesis reports the results of three studies. In the first study, I investigated auditory attention whilst controlling for crossmodal and executive factors which may have confounded the interpretation of previous studies. In the second study, I investigated whether another crossmodal factor, the control of eye movements, may also have contributed to the controversy regarding auditory attention. Lastly, I investigated whether some regions of the brain contain multiple overlapping signals, a finding which could explain how a cortical region might display ‘amodal’ properties, and participate in multiple cognitive functions simultaneously. As a whole, this thesis provides evidence that the DAN is a predominantly visuospatial attention network whose recruitment during auditory attention reflects indirect crossmodal mechanisms rather than the direct modulation of auditory information. In addition, this thesis provides evidence that a candidate frontotemporal network, which links executive regions of the prefrontal cortex with temporal auditory association areas, subserves top-down attention to non-spatial auditory features.