Identifying bidirectional total and non-linear information flow in functional corticomuscular coupling during a...

Area of Science:

• Neuroscience
• Biomedical Engineering
• Signal Processing

Background:

• Functional corticomuscular coupling (FCMC) relies on understanding information flow between EEG and SEMG.
• Traditional methods struggle with short time series data, necessitating new approaches.
• Investigating FCMC aids in understanding motor dysfunction, particularly in stroke patients.

Purpose of the Study:

• To introduce and validate a time-delayed maximal information coefficient (TDMIC) method for analyzing information flow in short time series.
• To investigate the directional specificity of total and nonlinear information flow in FCMC.
• To explore the neural mechanisms of motor dysfunction in stroke patients using TDMIC.

Main Methods:

• Developed TDMIC by incorporating a time-delayed parameter into the maximal information coefficient.
• Validated the TDMIC algorithm using linear and non-linear system models with short data.
• Applied TDMIC to analyze information flow in FCMC during a dorsiflexion task in healthy controls and stroke patients.

Main Results:

• TDMIC demonstrated superior directional information detection compared to traditional TE and TDMI methods.
• Healthy controls showed higher beta-band (14-30 Hz) FCMC information flow than gamma-band (31-45 Hz).
• Beta-band information flowed predominantly downwards (EEG to EMG), while gamma-band flowed upwards (EMG to EEG).
• Stroke patients exhibited significantly weaker bidirectional information flow in both beta and gamma bands compared to controls.

Conclusions:

• The TDMIC method effectively identifies information interactions in short time series.
• Beta band facilitates downward motor control signals, while gamma band transmits upward sensory feedback.
• Sensorimotor cortex regions are crucial for lower limb motor control.
• Stroke-induced brain damage impairs bidirectional cortical-muscle communication, leading to motor dysfunction.