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NCT Number: NCT04286776

Memory Retrieval and Encoding Investigated by Neural Stimulation

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.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Epilepsy Intractable Brain Diseases Central Nervous System Diseases Drug Resistant Epilepsy Epilepsy Nervous System Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Colorado, Denver, Aurora, Colorado, United States

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

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

Treatment and study plan

Direct electrical stimulation

Device

Stimulation will not exceed 0.75 mA and will be approved prior by study investigators. Each subject will have a safety threshold testing at the beginning of each session and if 'afterdischarges' occur the subject's stimulation threshold will be lowered.

Primary outcomes

  1. To use direct electrical stimulation to disentangle causal versus correlative biomarkers of verbal and spatial episodic memory

    Time frame: Up to 4 weeks (typical duration of hospital stay)

    • We will use linear mixed effects models and L2-penalized logistic regression classifiers to compare periods of successful and unsuccessful performance in our tasks

  2. To develop and test models of human brain dynamics in the presence of electrical stimulation

    Time frame: Up to 4 weeks (typical duration of hospital stay)

    • We will compare spectral indices of brain activity before and after stimulation as a function of stimulation parameters.

  3. To assess how reactivation of prior memories shapes subsequent recall and memory organization, including memory for the content, context and value of experiences.

    Time frame: Up to 4 weeks (typical duration of hospital stay)

    • 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).

  4. To determine whether state-dependent stimulation can separately be used to modulate encoding and retrieval processes

    Time frame: Up to 4 weeks (typical duration of hospital stay)

    • We will evaluate the closed-loop stimulation protocol described in Kahana et al. (2023) in both encoding and retrieval.

  5. To determine whether stimulation is more effective at modulating memory when targeted to regions with specific connectivity profiles to the medial temporal lobe

    Time frame: Up to 4 weeks (typical duration of hospital stay)

    • 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.

  6. To determine how simultaneous stimulation at multiple target sites can be optimized to modulate memory

    Time frame: Up to 4 weeks (typical duration of hospital stay)

    • We will compare recall rates during a free recall experiment with no brain stimulation, stimulation at one site, and stimulation at multiple sites.

Sponsors and collaborators

Lead sponsor

University of Pennsylvania

Other

Collaborators

  • Columbia University
  • National Institute of Neurological Disorders and Stroke (NINDS)

Registry information

Acronym: MEMREINS

Important dates

Study start
2014
Primary completion
2024
Study completion
2024
First posted
Feb 27, 2020
Registry last updated
Nov 5, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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