Overview
The objective of this study is to determine how visuomotor exploration relates to hippocampal activity along its long axis. The study will investigate the neurophysiological mechanisms in the hippocampus during (1) visual exploration in surgical patients using high-resolution iEEG, and (2) ambulatory exploration in patients implanted with RNS devices.
Description
Aim 1 - Visual Exploration in Surgical Patients Investigators will study 20 surgical patients with high-resolution intracranial EEG (iEEG) to investigate hippocampal activity during visual exploration. Participants will view between 10-15 panoramic environments using Meta Quest AR/VR glasses while their eye movements and head turns are tracked. Eye-tracking, head-turn, and iEEG data will be synchronized with visual stimuli, and intracranial EEG and single-unit data will be analyzed for changes in neuronal firing and brain activity before and after saccades.
Aim 2 - Ambulatory Exploration in RNS Patients and Healthy Controls Investigators will study 12 epilepsy patients with implanted responsive neurostimulator (RNS) devices and 24 healthy controls (HCs) during real-world exploration. Participants will walk through and explore visually distinct rooms while wearing synchronized high-density EEG (hdEEG), eye-tracking glasses, and body position sensors. Data from hippocampal iEEG, hdEEG, eye tracking, and motion sensors will be synchronized offline to examine brain-behavior relationships and the influence of cognitive load on saccade-hippocampal interactions.
Eligibility
Inclusion Criteria:
All subjects:
- Adults (18-70 years)
- Able to provide informed consent
Aim 1: Surgical epilepsy patients' inclusion criteria
- Implanted hippocampal depth electrodes for Stage 1 epilepsy surgery
- IQ=\>80\*
Aim 2: RNS patients Inclusion criteria
- Implanted RNS device with at least one hippocampal depth electrode
- At least 5 months post-implantation to avoid the post-implant effect
- Have a relatively low number of seizures, defined as =\<1 debilitating seizure per week
- Able to walk and wear research equipment without assistance
- IQ\>=80
Aim 2: Healthy Control Inclusion criteria • Able to walk and wear research equipment without assistance
Exclusion Criteria:
RNS patients, Aim 2:
• Any generalized tonic-clonic seizure(s) within the last year
All subjects:
- Legally blind
- Smoking tobacco, marijuana, recreational drugs or alcohol use within 1 week of cognitive testing
- Unable to give informed consent
- Pregnancy
