Neural underpinnings of bottom-up and top-down auditory attention in real-life environments

• Applicant: Dr. Bojana Mirkovic
• Subject Area: Biological Psychology and Cognitive Neuroscience ; Human Cognitive and Systems Neuroscience
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 432063183

We have an ability to focus on one listening task at time and push other surrounding sounds into background. This voluntary, top-down attention directed towards the most relevant sound stream can be interrupted by salient background sound events such as car horn - a bottom-up mechanism that allows us to timely react to events from our surroundings. Depending on the surrounding auditory scene and cognitive state of a listener some salient events can go undetected. This happens often in our daily routine, as we tend to ignore sounds irrelevant to us. Sometimes, however, not detecting a salient sound may be followed by severe consequences. Understanding the basis of such a common neural process as detection of a background salient event is on its own of great importance. Furthermore, only by understanding these processes it is possible to come up with solutions for alternative warnings if a relevant salient event is not detected by a listener.Not much is currently known about salient event processing in natural situations. Most findings on auditory attention come from highly-controlled laboratory experiments. The goal of this project is two-fold: (1) to investigate neural responses to salient events in real life and their influence on main listening task and (2) to explore the possibility of near-real-time classification of detected vs. undetected salient events for application in brain-computer interfaces (BCIs). I will achieve these goals in three separate electroencephalography (EEG) studies where human participants will be listening to speech with salient sounds occurring in background. As my aim is to study neural processes in real life conditions, all three studies will be conducted using an unobtrusive mobile EEG setup. I will start my investigation in controlled laboratory conditions using naturalistic stimuli, obtaining results comparable to those in previous literature. My next step will be to investigate neural responses to naturally occurring, uncontrolled salient events outside of laboratory, which is made possible by recent development of saliency models that can automatically estimate salience of events in an auditory scene. Once the neural correlates of salient event detection are known, the third study will investigate feasibility of an auditory BCI that could provide feedback on undetected salient events.I will apply two complementary analysis approaches- a novelty P3 analysis to investigate neural responses to background salient events and novel auditory envelope attention tracking approach to observe the influence of salient events on the top-down attention to foreground audio stream. Applying both methods to EEG data is likely to lead to robust neural correlates of salient event detection to the point of providing means of designing a reliable closed-loop auditory BCI for every-day scenarios.

• DFG Programme: Research Grants