Multimodal, longitudinal assessment of intracortical microstimulation

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neural Engineering

Background:

• The tissue response to penetrating microstimulation devices is a major hurdle for neuroprostheses.
• Chronic implantation and repeated electrical stimulation can affect device efficacy and lead to reactive tissue responses.

Purpose of the Study:

• To identify optimal parameters for chronically implanted microstimulation devices.
• To investigate the impact of repeated stimulation and tissue response on stimulation-driven behavior.
• To understand how device-tissue interface quality affects psychophysical thresholds.

Main Methods:

• Psychophysical experiments were conducted using multichannel cortical implants in the auditory cortex of rats.
• Auditory cortical microstimulation was used to assess behavioral responses.
• Impedance spectral changes and post-vivo histology were analyzed alongside psychophysical thresholds.

Main Results:

• Cortical depth and days post-implantation significantly influenced the psychophysical threshold of auditory cortical microstimulation.
• Changes in impedance spectra correlated with observed psychophysical threshold variations.
• Post-vivo histology provided insights into the tissue's reactive response to the implants.

Conclusions:

• Device-tissue interfacial quality and the host tissue's response are critical factors in neuroprosthetic efficacy.
• Understanding these factors is essential for developing effective, chronically implanted microstimulation devices for clinical applications.
• This research provides valuable data to advance the development of neuroprosthetic technologies.