Seminars in Hearing Research at Purdue (SHRP)

Date: Thursday, September 23, 2021

Time: 10:30 – 11:20 am

Location: LYLE 1150

Title: A system-identification approach to characterize cortical temporal coding

Speaker: Ravinderjit Singh, PhD candidate, BME/MSTP (Bharadwaj lab)

Abstract:
Many studies have investigated how subcortical temporal processing, measured via brainstem evoked potentials (e.g., ABRs and FFRs) may be influenced by aging, hearing loss, musicianship, and other auditory processing disorders. However, human studies of cortical temporal processing are often restricted to the 40 Hz steady-state response. One possible reason for the limited investigation is the lack of a fast and easy method to characterize temporal processing noninvasively in humans over a range of modulation frequencies. Without a broadband characterization of cortical temporal processing, it is difficult to disentangle the different components that may contribute to the overall EEG response, and discover their respective functional correlates. Here, we use a system-identification approach where white noise, modulated using a modified maximum length sequence (m-seq), is presented to quickly obtain a stereotypical and repeatable auditory cortical “impulse” response (ACR) capturing broadband cortical modulation coding (up to 75 Hz) with EEG. Using principal component analysis (PCA) across different EEG sensors, we found that the overall response is composed of five components that can be distinguished by virtue of latency, and/or scalp topography. Furthermore, the components spanned different frequency ranges within the overall temporal modulation transfer function (tMTF), and differed in their sensitivities to manipulations of attention and/or task demands. Interestingly, we also find that the ACR shows nonlinear behavior, in that the relative magnitudes of the constituent components are different when measured using broadband modulations versus a series of sinusoidal modulations.

Zoom Info:

https://purdue-edu.zoom.us/j/9​3108158900?pwd=RDdTQ0Z4UE9Rb0JUenhjMG1SMkp2QT09

Meeting ID: 931 0815 8900

Passcode: 11501150

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The working schedule for this academic is here:

https://purdue.edu/TPAN/hearing/shrp_schedule

The titles and abstracts of the talks will be added here:

https://purdue.edu/TPAN/hearing/shrp_abstracts