Quantifying task-locked information transmission between cortical areas with TMS-EEG

Area of Science:

• Neuroscience
• Cognitive Science
• Biomedical Engineering

Background:

• Understanding task-locked neural network activation and information transmission is crucial for deciphering brain function.
• Existing methods may not fully capture the dynamic nature of neural communication between cortical areas.

Purpose of the Study:

• To develop and validate Transcranial Magnetic Stimulation combined with Electroencephalography (TMS-EEG) technology.
• To dynamically quantify information transmission and neural network activation during a visually guided saccade task.
• To investigate directed information flow between the prefrontal cortex (PFC) and posterior parietal cortex (PPC).

Main Methods:

• 30 participants performed a visually guided gap saccade task.
• TMS-EEG data were recorded with TMS pulses applied to PFC and PPC at different task stages.
• The Directed Transfer Function (DTF) method was used to analyze information flow in alpha, beta, and gamma frequency bands.

Main Results:

• Successful task performance with >90% accuracy and mean saccade latency of 132.25 ±22.59 ms.
• Significant differences in information flow within gamma bands between PFC and PPC were observed at different time points.
• Specific electrode activity (C3, P3) identified as hubs for information transfer during task processing.

Conclusions:

• DTF values derived from TMS-EEG effectively characterize information flow between cortical areas during a saccade task.
• This approach offers a novel method for quantifying dynamic changes in connectivity and causality.
• The study demonstrates TMS-EEG's potential for mapping functional brain networks.