Microelectrodes in Epilepsy

The purpose of this study is to test microelectrodes in intracranial monitoring to see if they will provide novel information on the epileptic potential of the implanted brain tissue. A secondary objective is to investigate the activity of single neurons during specific cognitive tasks.

The standard-of-care for medically refractory epilepsy is resective brain surgery. In certain patients, precise localization of the epileptic focus is done using intracranial EEG (iEEG) recording. In this type of EEG recording, electrodes are placed on the brain surface or inserted into the brain through an opening in the skull. In addition to standard electrode recording, this study will use ultra thin microelectrodes. Microelectrodes are only several micrometers thick and are useful because they are able to record the activity of single neurons in isolation. Such recordings have tremendous clinical potential in epilepsy surgery and tremendous research potential in cognitive neuroscience.

Patients who qualify for this study will be implanted with standard electrodes as well as microelectrodes for their intracranial seizure monitoring.

Feasibility of Microelectrode Technology to Isolate Place Responsive Neurons in the Human Hippocampus as Measured by the Number of Place Responsive Neurons.

With the occipito-temporal implantation approach of implantation of microelectrodes, feasibility will measured by the number of place responsive neurons that could be isolated.

How Precise the Frequencies (Alpha, Beta, Delta, Theta, Gamma, and High-gamma) of Neural Brain Activity Predict the Speed of the Participant at Performing the Cognitive Task (Accuracy Measured in Percentage).

Secondary objective is to investigate whether it is possible to predict the speed of which each participant is performing and navigating during the cognitive task via the intracranial spectral EEG changes (alpha, beta, delta, theta, gamma, and high-gamma) during these tasks. Accuracy of frequency band (brain waves) predicting speed during specific cognitive tasks is measured by how precisely the frequency band predicts navigational speed and is expressed as a percentage of correct prediction.

Inclusion Criteria: 18-65 year old male or female right or left handed IQ>70 medically refractory focal epilepsy requiring intracranial EEG for pre-surgical evaluation deemed medically necessary no contraindications to intracranial electrode study able and willing to participate in research Exclusion Criteria: does not meet the inclusion criteria