This study will help describe how the human brain works when a person sees something, hears something, learns something, or thinks about something by recording brain activity that occurs when the person does a series of computer tasks. This study will be offered to people who are in the hospital to be monitored for epilepsy by using electrodes placed in the brain. The study will record brain activity that occurs when a patient does a memory task, for example.
Patients who have elected to have invasive electrophysiological monitoring for epileptic activity are invited to participate in this study. While the electrodes are in place, patients are asked to view several scenarios on a laptop computer. During these scenarios, for example, patients are asked to click a mouse button if they see the same picture twice in a row or to remember a film clip of a scooter ride. Trigger points in the computer scenarios are recorded on a separate channel alongside the brain-wave activity to allow correlation between the brain activity and the task requested in the scenario. Using this technique, researchers can determine what areas of the brain were active during recognition or recall activities.
Study Type
OBSERVATIONAL
Enrollment
6
Swedish Medical Center Epilepsy Center
Seattle, Washington, United States
Reveal induced neuronal activity
In the preprocessing stage, potential electrical interference will be removed from the raw signal using a linear-phase notch FIR filter. Each electrode will be de-referenced by subtraction of the averaged signal of all the electrodes, thus discarding non-neuronal contributions. Time-frequency decompositions will be calculated for each electrode based on Fourier transform amplitude spectrum in a 160ms sliding window with average step size of 6ms. This process is done per trial and averaged across trials in order to reveal induced neuronal activity, which is not time-locked to the stimuli.
Time frame: Approximately 3 hours over the course of 2-3 days during in-patient invasive electrophysiological monitoring.
Calculate evoked response potentials.
Evoked response potentials (ERPs) will be calculated by averaging the raw signal across the presentation of a specific stimulus for each patient, such as all samples of patients watching the movie clip.
Time frame: Approximately 3 hours over the course of 2-3 days during in-patient invasive electrophysiological monitoring.
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