Assessing Brain Hyperexcitability with Transcranial Magnetic Stimulation and Electroencephalography

Take an epilepsy patient with an electroencephalography, or EEG, cap to record brain activity.

The patient’s pre-recorded brain scan reveals a deep-seated structural abnormality that is functionally connected to a target superficial cortical region.

Attach electrodes to the contralateral hand to capture muscle contractions.

Secure an infrared detector to track and nullify head movement and use neuronavigation to align the head position with the brain scan.

Position the magnetic coil over the cortical region responsible for hand movement. Apply the lowest-intensity pulse that elicits hand muscle contraction, confirming cortical neuron stimulation.

Deliver suprathreshold pulses to stimulate the target cortical region, inducing neural activity that propagates to the abnormal brain area and other functionally connected regions in the epileptic network.

Record the brain activity to identify abnormal EEG responses indicative of neuronal hyperexcitability in the epileptic brain.

Map the origin of the abnormal EEG peaks to locate the seizure-onset zone.

Prior to testing, determine the two TMS target regions by superimposing each subject's functional connectivity map onto each subject's structural