The investigators performed direct electrical stimulation of the claustrum in drug-resistant epilepsy patients underwent SEEG monitoring.The investigators observed the neural activities before, during, and after stimulation and the claustrum-cortical network to figure out the role of claustrum in consciousness and its underlying electrophysiological mechanism.

The patients underwent SEEG with at least one electrode targeting the claustrum. The investigators used the claustrum as a target for both mapping and CCEP, recording changes in cortical electrical activity.

Researchers categorized patients' clinical responses as normal, mild, moderate, or severe based on their subjective clinical response.

Using SEEG-implanted electrodes, the investigators applied electrical stimulation of varying intensities to the CLA while observing and recording EEG power changes across six spectral frequency bands during the pre-stimulation, stimulation, and post-stimulation periods.

EEG Frequency Bands

• delta (1-4 Hz)
• theta (5-8 Hz)
• alpha (9-12 Hz)
• beta (13-30 Hz)
• low gamma (31-70 Hz)
• high gamma (71-150 Hz)

All cortical-evoked responses were averaged by time-locking the recordings to the onset of each electrical stimulus (zero) off-line, within a time window of -200 to +400 mses, to quantify the morphology.

The N1 peak, identified as the first negative deflection distinguishable from the stimulus artifact, was the primary focus due to its clear visibility and reproducibility across different stimulations.

The root mean square (RMS) value will be calculated for different cortical locations during time windows that encompass both the N1 peak(early response time time window) and the baseline.

A paired one-sample t-test will be used to compare the RMS values in the early response time window across different cortical sites with the RMS values in the baseline.