BME PhD Preliminary Exam Announcement for Madhurima Patra (M. Heinz, advisor)

Everyone is invited to attend the public presentation beginning at 2:30 pm.

Research title:  Neural Correlates of Spectro-Temporal Modulation Detection : Insight from Cross-Species EEG Studies

Date: November 20, 2024

Time: 2:30 pm

Location: LYLE 1150 and Zoom: https://purdue-edu.zoom.us/my/mheinz.purdue

Committee members: Michael Heinz ( Chair), Edward Bartlett, Anne Sereno, Hari Bharadwaj

Abstract: 

Individuals with sensorineural hearing loss often struggle to understand speech in noisy environments despite communicating well in quiet settings. Natural sounds exhibit complex spectro-temporal variations in intensity across time and frequency domains. Selective tuning to these Spectro-Temporal Modulations (STMs) is crucial for understanding naturalistic sounds and speech intelligibility in noise. Recent studies suggest that STM stimuli can be good non-language predictors of speech-in-noise intelligibility, forming the basis for a commercial clinical test. However, the underlying mechanisms remain unknown. Our work uses STM stimuli with dynamically modified parameters to study behavioral and electroencephalographic (EEG) signatures responsible for perceptual differences across populations. To gain mechanistic insights, chinchillas are invaluable pre-clinical animal models for exploring auditory functions under controlled hearing-loss conditions. A recently developed multi-channel mini-EEG cap for lightly sedated chinchillas enables reliable cortical response acquisition. Preliminary results indicates that cortical responses reflect STM structure changes in humans and chinchillas. Response magnitude increases with modulation depth, primarily reflected in low-frequency neural oscillations. With increasing signal-to-noise ratio, responses become less scattered and show reduced coherence across channels throughout the cortical topology, concentrating on the contralateral side. This cross-species approach allows direct comparison of analogous responses on a perceptual level, enhancing translational potential. It demonstrates how changes in STM structure are reflected in neural signatures of both species, providing a comprehensive understanding of auditory processing mechanisms across humans and chinchillas. This research is particularly important for aging populations and hearing-aid recipients, as it explores the limitations of missing perceptual information and its impact on speech intelligibility in noisy environments.