Focal thalamic infrared neural stimulation propagates dynamical transformations in auditory cortex

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neural Engineering

Background:

• Infrared neural stimulation (INS) is a promising neuromodulation technique with improved safety and focus over electrical methods.
• Understanding INS-induced neural dynamics is crucial for optimizing its clinical applications and developing new stimulation paradigms.

Purpose of the Study:

• To investigate the local network dynamics of INS entrainment within the auditory thalamocortical circuit.
• To characterize neural responses to varying INS parameters and explore spike-field coupling.

Main Methods:

• Utilized a chronically implanted rat model to measure local field potential (LFP) recruitment via INS.
• Analyzed linear and nonlinear LFP activity, performed spectral decomposition for band entrainment, and measured spike-LFP coherence.

Main Results:

• INS increased LFP amplitude log-linearly with energy, primarily entraining to beta and gamma bands, with synchrony up to 200 Hz.
• Observed nonlinear, chaotic neuronal oscillations linked to information transfer.
• Correlated spike coupling to LFP activity, proposing an energy-dependent network activation model.

Conclusions:

• INS reliably induces robust neural activity and modulates cortical field potentials in a stimulus-dependent manner.
• Results inform the design of all-optical thalamocortical auditory neuroprostheses for broad coverage.