Auditory spatialization approaches differentially recruit sensory-biased prefrontal cortex

Past spatial auditory studies have used various approaches to manipulate perceived source location, including pure interaural time differences (ITDs), pure interaural level differences (ILDs), and more natural and realistic head-related transfer functions (HRTFs). Previously, we showed that the effectiveness of spatial attention is strongest for HRTF simulations and weakest for pure ITDs, but the mechanisms explaining such differences remain unclear. The prefrontal cortex (PFC) supports many higher-order cognitive functions, including working memory. Visual-biased PFC regions show greater activation during auditory tasks that require spatial processing than those that do not, suggesting that visual-biased PFC regions play an important role in auditory spatial cognition. To investigate the interaction between spatial cues and spatial processing, we conducted an fMRI study testing different auditory tasks (spatial, non-spatial, and passive) and different spatialization approaches (ITD, ILD, or HRTF). In spatial tasks, HRTFs yielded the best behavioral performance and strongest activation across PFC; ITDs yielded the lowest performance and weakest activation. Visual-biased PFC regions showed greater activation during spatial than nonspatial tasks. These results provide new insights into how spatial cues interact with PFC regions during auditory tasks.