Neural Basis of Human Working Memory

This ClinicalTrials.gov entry corresponds to the Neural Basis of Human Working Memory protocol approved under Vanderbilt University Medical Center IRB #251231.

This study investigates the neural activity underlying human working memory, via local field potential changes (macro level) and/or single neuronal spiking changes (micro level) from depth electrodes placed for invasive seizure monitoring. Subjects will complete neurocognitive tasks while neural recordings are collected. Some patients will complete neurocognitive tasks while stimulation is applied via depth electrodes. Further understanding the neural activity changes underlying normal and impaired working memory may help to identify novel diagnostic methods and treatments for impaired working memory and may support the use of stimulation for treatment of memory disorders.

Study Overview

• Status: Recruiting
• Conditions: Memory Disorders

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

• Study Contact: Name: Lucas Chang, BS; Phone Number: 615-421-3046; Email: isabel.long@vumc.org
• Study Contact Backup: Name: Christos Constantinidis, PhD; Phone Number: +1 (615) 936-2020; Email: christos.constantinidis.1@Vanderbilt.Edu

Study Locations

• United States
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Recruiting
      • Vanderbilt University Medical Center
      • Contact: Isabel Long, BS; Phone Number: 615-421-3046; Email: isabel.long@vumc.org
      • Contact: Christos Constantinidis, PhD; Phone Number: (615) 936 - 2020; Email: christos.constantinidis.1@Vanderbilt.Edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients with medically refractory epilepsy who have undergone depth electrode placement for localization of their refractory seizures via SEEG monitoring.

Description

Inclusion Criteria:

• Undergoing SEEG monitoring at Vanderbilt University Medical Center
• Age >18
• English speaking

Exclusion Criteria:

• Age <18
• Not able to complete questionnaires (unable to comprehend instructions or follow directions)

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Epilepsy patients; All participants will be patients with medically refractory epilepsy who have undergone depth electrode placement for stereo EEG monitoring for seizure localization. Participants will complete working memory tasks and EEG recordings will be concurrently collected from their depth electrodes. Some subjects will undergo macro-micro electrode implantation as a part of their SEEG implantation procedure for the purpose of EEG macro (local activity) and micro (single-unit) recordings. Some subjects will complete working memory tasks with stimulation applied during task completion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Local field potential changes in response to working memory tasks	Local field potential changes are from intracranial neural recordings taken while patients complete spatial working memory tasks. In the manual remember 1 remember 2 task, patients are instructed to hold down a cursor on a central location box colored one color or another on screen, while two boxes in locations sequentially flash on screen. Depending on the central location box color, the patient will drag their cursor to the first or second location box shown, after the central box has disappeared from screen. In the retro remember 1 remember 2 task, the color of the central box color is not shown until both location boxes have flashed onscreen. In the manual version, the central location box color is constant throughout the trial.	During patient's epilepsy monitoring stay, approximately 20-30 minutes
Single unit neuronal spiking changes in response to memory tasks	Single neuron spiking activity is recorded through SEEG micro neural recordings while patients complete working memory tasks.	During patient's epilepsy monitoring stay, approximately 20-30 minutes
Behavioral performance changes with simulation	Bipolar stimulation through pre-selected SEEG electrodes in the prefrontal cortex and surrounding areas will occur during the remember 1 remember 2 working memory tasks. Stimulation will be performed via the Ripple Neuromed Summit system. Stimulation will be tested with each patient prior to task to determine safety and tolerability, while patient is monitored by a neurosurgeon or neurologist.	During patient's epilepsy monitoring stay, approximately 20-30 minutes

Collaborators and Investigators

• Sponsor: Vanderbilt University Medical Center
• Collaborators: National Institute of Mental Health (NIMH)

Study record dates

Study Major Dates

• Study Start (Actual): June 4, 2025
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: May 23, 2026
• First Submitted That Met QC Criteria: May 23, 2026
• First Posted (Actual): June 1, 2026

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 23, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Working Memory; Stereo Electroencephalography (SEEG); Neural stimulation; Memory disorders
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Neurobehavioral Manifestations; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Memory Disorders
• Other Study ID Numbers: 251231 (Vanderbilt University Medical Center IRB); 1R21MH139624-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No