Memory Retrieval and Encoding Investigated by Neural Stimulation

Not Applicable

Active, not recruiting

• Conditions: Epilepsy Intractable
• Interventions: Device: Direct electrical stimulation

• Registration Number: NCT04286776
• Lead Sponsor: University of Pennsylvania

Brief Summary

The purpose of this research is to understand biomarkers of human memory through correlational analyses and to use focal electrical stimulation as a causal manipulation to understand how biomarkers of memory relate to other brain states and behavioral measures.

Detailed Description

Not available

Study Timeline

• Study Start: 2014-10-12
• Study First Submitted: 2020-02-24
• Study First Submitted QC: 2020-02-24
• Study First Posted: 2020-02-27
• Status Verified: 2024-11
• Last Update Submitted: 2024-11-04
• Last Update Posted: 2024-11-05
• Primary Completion: 2024-12-31
• Study Completion: 2024-12-31

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 800

Inclusion Criteria

1. Expected to undergo intracranial implantation and postoperative electroencephalographic monitoring as part of a standard clinical procedure for the treatment of pharmacologically resistant epilepsy
2. Age 18 or older

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Exclusion Criteria

1. Any physical or cognitive disability or illness that would limit their ability to perform cognitive tasks
2. Any medical condition that would, in the investigator's opinion, limit the subject's participation in the study.
3. Unable or unwilling to provide informed consent
4. MRI contraindications

Standard clinical care includes a pregnancy test for female patients prior to the surgical implantation of the electrodes. Pregnant women are not surgically implanted.

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Direct Electrical Stimulation	Direct electrical stimulation	Stimulation will be applied concurrently with the task, if applicable, and stimulation trials will be interleaved with sham trials, where no stimulation is delivered.

Primary Outcome Measures

Name	Time	Method
To determine whether state-dependent stimulation can separately be used to modulate encoding and retrieval processes	Up to 4 weeks (typical duration of hospital stay)	4. We will evaluate the closed-loop stimulation protocol described in Kahana et al. (2023) in both encoding and retrieval.
To determine whether stimulation is more effective at modulating memory when targeted to regions with specific connectivity profiles to the medial temporal lobe	Up to 4 weeks (typical duration of hospital stay)	5. We will compare recall rates during a free recall experiment with brain stimulation at sites with high network-mediated activation, as described in Solomon et al. (2018), versus low network-mediated activation.
To determine how simultaneous stimulation at multiple target sites can be optimized to modulate memory	Up to 4 weeks (typical duration of hospital stay)	6. We will compare recall rates during a free recall experiment with no brain stimulation, stimulation at one site, and stimulation at multiple sites.
To use direct electrical stimulation to disentangle causal versus correlative biomarkers of verbal and spatial episodic memory	Up to 4 weeks (typical duration of hospital stay)	1. We will use linear mixed effects models and L2-penalized logistic regression classifiers to compare periods of successful and unsuccessful performance in our tasks
To develop and test models of human brain dynamics in the presence of electrical stimulation	Up to 4 weeks (typical duration of hospital stay)	2. We will compare spectral indices of brain activity before and after stimulation as a function of stimulation parameters.
To assess how reactivation of prior memories shapes subsequent recall and memory organization, including memory for the content, context and value of experiences.	Up to 4 weeks (typical duration of hospital stay)	3. We will mathematical models of neural similarity described in detail in Halpern (2024) and Manning (2011, 2012) to test the reactivation mechanisms described in Lohnas et al. (2014) and Healey and Kahana (2015).

Trial Locations

Locations (11)

Columbia University; 🇺🇸 New York, New York, United States

Dartmouth-Hitchcock Medical Center; 🇺🇸 Lebanon, New Hampshire, United States

University of Colorado, Denver; 🇺🇸 Aurora, Colorado, United States

Emory University Hospital; 🇺🇸 Atlanta, Georgia, United States

National Institute of Neurological Disorders and Stroke; 🇺🇸 Bethesda, Maryland, United States

Beth Israel Deaconess Medical Center; 🇺🇸 Boston, Massachusetts, United States

Mayo Clinic; 🇺🇸 Rochester, Minnesota, United States

Hospital of the University of Pennsylvania; 🇺🇸 Philadelphia, Pennsylvania, United States

Thomas Jefferson University Hospital; 🇺🇸 Philadelphia, Pennsylvania, United States

UT Southwestern Medical Center; 🇺🇸 Dallas, Texas, United States

University of Texas Health Science Center at San Antonio; 🇺🇸 San Antonio, Texas, United States