Assessment of Corticospinal Excitability in Awake Rodents Using EMG-Controlled Intracortical Stimulation.

Area of Science:

• Neuroscience
• Motor Control
• Neuroplasticity

Background:

• Assessing corticospinal excitability (CSE) is vital for studying motor system plasticity and recovery after neurological injury.
• Current rodent models often use anesthesia, which significantly alters CSE and plasticity mechanisms.
• Studying CSE in awake animals is challenging due to behavioral influences on motor system excitability.

Purpose of the Study:

• To develop and validate a novel approach for assessing CSE in awake, behaving rodents.
• To enable reliable and repeatable measurements of evoked motor responses under defined behavioral conditions.
• To provide tools facilitating neuroplasticity research in animal models.

Main Methods:

• Designed a system for CSE assessment in awake rodents using chronically implanted intracortical and intramuscular electrodes.
• Developed a custom software system to control cortical stimulation based on precise EMG activity parameters.
• Provided fabrication schematics, material lists, and a MATLAB codebase for the system and data analysis.

Main Results:

• Successfully established a method for reliable CSE assessment in awake behaving rodents.
• The system ensures repeatable stimulation conditions linked to ongoing motor activity.
• Demonstrated the utility of the approach for studying interventions like paired associative stimulation (PAS) and theta-burst stimulation (TBS).

Conclusions:

• The developed system overcomes limitations of anesthetized rodent models for CSE assessment.
• This novel approach facilitates the study of neuroplasticity and motor recovery in more physiologically relevant conditions.
• The provided tools and protocols aim to advance research in neurorehabilitation and the understanding of motor system plasticity.