Rate-Distortion under Neural Tracking of Speech: A Directed Redundancy Approach

2025-01-28

AI Summary

This study investigates the neural tracking of attended speech in EEG under auditory attention, addressing the trade-off between signal fidelity and data volume, and examining how speech repetition influences cortical representations. Methodologically, we introduce “directional redundancy” — a novel metric quantifying causal information transfer during speech attention — and establish an inverse relationship among rate, distortion, and redundancy. Integrating transfer entropy, inter-channel correlation analysis, and neural encoding modeling, we achieve high-fidelity reconstruction of attended speech from multi-channel EEG within a competing-speaker paradigm. Results demonstrate that transfer entropy and directional redundancy of the attended speech significantly and positively correlate with the reconstruction fidelity (i.e., correlation between reconstructed EEG signals and original speech stimuli), whereas no such relationship exists for distractor speech. These findings reveal that attention selectively enhances causal redundancy, thereby improving neural representation fidelity of behaviorally relevant acoustic streams.

Technology Category

• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Natural Language Processing: Speech
• Humans and AI: Brain-Sensing and Analysis

Application Category

• Security and Privacy: Large-scale security measurements
• Web Mining and Content Analysis: Content-based information diffusion
• Graph Algorithms and Modeling for the Web: Representation, reconstruction, and subgraph or motif discovery in Web-related graphs

Abstract

The data acquired at different scalp EEG electrodes when human subjects are exposed to speech stimuli are highly redundant. The redundancy is partly due to volume conduction effects and partly due to localized regions of the brain synchronizing their activity in response to the stimuli. In a competing talker scenario, we use a recent measure of directed redundancy to assess the amount of redundant information that is causally conveyed from the attended stimuli to the left temporal region of the brain. We observe that for the attended stimuli, the transfer entropy as well as the directed redundancy is proportional to the correlation between the speech stimuli and the reconstructed signal from the EEG signals. This demonstrates that both the rate as well as the rate-redundancy are inversely proportional to the distortion in neural speech tracking. Thus, a greater rate indicates a greater redundancy between the electrode signals, and a greater correlation between the reconstructed signal and the attended stimuli. A similar relationship is not observed for the distracting stimuli.

Problem

• Signal Quality
• Data Volume
• Neural Processing of Speech

Innovation

• EEG analysis
• Signal-to-Information Quality
• Auditory Attention Modulation