Spatial Scene Recognition Memory in Epilepsy Surgery

BEHAVIORAL

Virtual Tour Recognition Memory Task

Participants are passively navigated through virtual tour scenes (5-second video clips) during a study phase and are asked to generate descriptive names for each scene. During the test phase, they view novel, spatially similar (same configuration, different objects), or identical scenes and rate familiarity, indicate old/new judgments, report déjà vu sensations, and attempt to recall scene names. The task consists of two study-test blocks. This is a cognitive/behavioral assessment, not a therapeutic intervention.

DEVICE

Intracranial EEG Recording with Research Electrodes (Aim III only)

Patients undergoing clinically indicated stereoelectroencephalography (SEEG) for seizure localization have electrodes implanted at locations determined solely by clinical need. In a subset of patients, FDA-approved research electrodes (Dixi micro-macro electrodes or Behnke-Fried As-Tech electrodes with tetrode components) substitute standard clinical electrodes at the same clinically determined locations. These electrodes have the same geometry as clinical electrodes and are FDA-approved. The tetrode component enables single-neuron recording for research purposes and adds no additional risk. Electrode placement is not altered by study participation. Local field potentials (LFP) and, where available, single-unit data are recorded during the virtual tour task and resting state.

DIAGNOSTIC_TEST

MRI Neuroimaging and Neuropsychological Assessment (Aim I)

Pre- and post-surgical structural MRI (T1-weighted, diffusion-weighted imaging, resting-state fMRI) obtained as part of the clinical epilepsy surgery evaluation at Emory University. Extensive neuropsychological battery administered pre- and post-operatively (6 months and 1 year) including Wechsler memory scales, Rey-Osterrieth Complex Figure, confrontation naming, and additional measures.

Scene familiarity discrimination accuracy

Time frame: From enrollment until the end of eight weeks, during which time testing is scheduled (Aim II), or during the hospitalization for invasive EEG studies (Aim III). Participants in Aim I can undergo repeat testing (six months, one year, etc.)

Rate of correct familiarity judgments for spatially similar test scenes versus novel scenes (recognition without identification/RWI effect), measured as the proportion of "familiar" responses to configurally matched scenes minus false alarm rate to novel scenes.

Scene recall accuracy

Time frame: From enrollment until the end of eight weeks, during which time testing is scheduled (Aim II), or during the hospitalization for invasive EEG studies (Aim III). Participants in Aim I can undergo repeat testing (six months, one year, etc.)

Proportion of test scenes for which participants correctly recall the name or identifying details of the corresponding study scene (verified recall), separately for identical repeat scenes and configurally similar scenes.

Lesion-symptom correlation for familiarity and recall (Aim I)

Time frame: Testing is scheduled within eight weeks of enrollment for all patients, with repeat testing at six and 12 months after surgery for those enrolled pre-operatively

Voxel-based lesion-symptom mapping (VBLSM) correlating surgical lesion volumes in temporal lobe subregions (temporopolar, perirhinal, entorhinal, parahippocampal, hippocampal) with familiarity and recall behavioral scores.

ERP amplitude and latency associated with familiarity and recall (Aim II)

Time frame: During EEG recording session

Amplitude and latency of event-related potential components (FN400, late positive component) in specified scalp regions (e.g., LAS, RAS, LPS, RPS) as a function of scene familiarity and recall conditions.

Intracranial theta and gamma power and connectivity during familiarity judgments (Aim III)

Time frame: During intracranial EEG monitoring (typically 1-2 weeks hospital stay)

Theta (3-7 Hz) and gamma-band (30-150 Hz) event-related synchronization/desynchronization in parahippocampal, perirhinal, entorhinal, and hippocampal contacts during familiarity versus recall conditions, plus functional connectivity measures (imaginary coherence, phase-amplitude coupling).

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