Neural Basis of Human Working Memory

August 20, 2026 updated by: Christos Constantinidis, Vanderbilt University Medical Center

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

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

100

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: 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.
Behavioral: Neurocognitive Tasks
Participants complete computerized neurocognitive tasks assessing working memory, response inhibition, decision-making, reward processing, and other related cognitive functions during sEEG monitoring. Tasks may include the stop signal reaction time task, the n-back working memory task, the delayed response task, the match/nonmatch task, the gambling task, the card guessing task, and the emotional stop signal reaction time task. Intracranial neural activity is recorded during task performance, and select tasks may include research electrical stimulation delivered through the implanted sEEG electrodes.
Device: Ripple Neuromed Summit System
Neurophysiology system designed to allow recording of neural signals as well as delivery of neural stimulation. The system is a portable unit which is connected to cables connected to the clinical electrodes. Neurophysiology signals from the electrodes can be recorded, amplified, and processed by the unit. The unit also has the ability to deliver electrical stimulation through the electrodes according to programmed parameters.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Local field potential changes in response to working memory tasks
Time Frame: During patient's epilepsy monitoring stay, approximately 20-30 minutes
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
Time Frame: During patient's epilepsy monitoring stay, approximately 20-30 minutes
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 stimulation
Time Frame: During patient's epilepsy monitoring stay, approximately 20-30 minutes
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

This is where you will find people and organizations involved with this study.

Sponsor

Vanderbilt University Medical Center

Collaborators

National Institute of Mental Health (NIMH)

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

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)

August 24, 2026

Last Update Submitted That Met QC Criteria

August 20, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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