Seminars in Hearing Research

Date: Thursday, February 13, 2025

Location: Nelson 1215

Time: Noon - 1:00 pm

Speaker:   Edward Bartlett, Associate Dean, College of Science, Professor of Bio and BME  

Title: Focal Infrared Neural Stimulation Propagates dynamic Transformations in Auditory Cortex.

Abstract: Significance: Infrared neural stimulation (INS) has emerged as a potent neuromodulation technology, offering safe and focal stimulation with superior spatial recruitment profiles compared to conventional electrical methods. However, the neural dynamics induced by INS stimulation remain poorly understood. Elucidating these dynamics will help develop new INS stimulation paradigms and advance its clinical applications. Aim: In this study, we assessed the local network dynamics of INS entrainment in the auditory thalamocortical circuit using the chronically implanted rat model; our approach focused on measuring INS energy-based local field potential (LFP) recruitment induced by focal thalamocortical stimulation. We further characterized linear and nonlinear oscillatory LFP activity in response to single-pulse and periodic INS and performed spectral decomposition to uncover specific LFP band entrainment to INS. Finally, we examined spike-field transformations across the thalamocortical synapse using spike-LFP coherence coupling. Results: We found that INS significantly increases LFP amplitude as a log-linear function of INS energy per pulse, primarily entraining to specific LFP bands. A subset of neurons demonstrated nonlinear, chaotic oscillations that were sensitive to information propagation across thalamocortical circuits. Finally, we utilize spike-field coherences to correlate spike coupling to LFP frequency band activity and suggest an energy-dependent model of network activation resulting from INS stimulation. Conclusions: We show that INS reliably drives robust network activity and can potently modulate cortical field potentials across a wide range of frequencies in a stimulus parameter-dependent manner. Based on these results, we propose design principles for developing full coverage, all-optical thalamocortical auditory neuroprostheses.

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The working schedule is available 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