HRC Seminar: KC Lee

10:30 am on Friday, October 6, 2017
1:00 pm on Friday, October 6, 2017
610 Commonwealth Avenue, Room 101
Title: Behavioral and neurophysiological evidence regarding the influence of oculomotor circuitry on auditory spatial tasks. Abstract: Spatial cues play an important role in segregating auditory objects in a complex acoustical scene. Spatial attention is often considered to be supramodal, e.g., crossmodal spatial cues can enhance the perception of stimuli in another modality when presented in the same location. Therefore, it is not surprising to find similarities between auditory and visual spatial attentional networks. An outstanding question, however, is how the supramodal spatial attention network functions if the listener attends instead to non-spatial acoustic features, e.g., pitch? In vision, the coupling between oculomotor circuitry and the attentional network is well studied. Are there behavioral consequences related to this tight oculomotor coupling in the context of auditory spatial tasks? We addressed these questions using three approaches. First, in a series of neuroimaging experiments using combined magneto- and electro-encephalography constrained by anatomical MRI data, we explored how different cortical regions are recruited for auditory spatial and non-spatial attention both during maintenance of attention to a single auditory stream and switching of attention between streams. Second, based on our newly developed sparse-plus-low-rank graphical approach that enables modelling of structured relationships between time series in a big data setting, we are starting work inferring functional connectivity between cortical regions to tease apart how different cortical nodes are coordinated to perform different auditory attentional tasks. Finally, we used psychophysical methods to address whether there are behavioral consequences related to this tight coupling between the oculomotor and attentional networks in the context of auditory spatial tasks. One of the major clinical challenges facing hearing scientists is to understand why there is such great variability in performance, not predicted by standard audiological assessment, when listeners are tasked with attending to sounds in noisy, everyday settings. While our understanding of this problem, termed “hidden hearing loss,” has made great advances at cochlear and brainstem levels, our field has generally not considered how individual differences at the cortical level could also contribute to this performance variability. This is particularly pertinent to understanding why many people diagnosed with different neurodevelopmental disorders (e.g., autism spectrum disorder and fetal alcohol spectrum disorder) find it particularly challenging to communicate in noisy settings. The long-term goal of our laboratory is to understand how our auditory attentional network can be disrupted due to different neurodevelopmental deficits so we can identify potential strategies (e.g., crossmodal training) to help afflicted individuals improve social communication outcomes in their everyday lives.