Memory Retrieval and Encoding Investigated by Neural Stimulation
Trial Snapshot
- Phase
- Not Applicable
- Status
- Active, not recruiting
- Sponsor
- University of Pennsylvania
- Enrollment
- 800
- Locations
- 22
- Primary Endpoint
- To use direct electrical stimulation to disentangle causal versus correlative biomarkers of verbal and spatial episodic memory
Study Overview
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.
Study Design
- Study Type
- Interventional
- Allocation
- Na
- Intervention Model
- Single Group
- Primary Purpose
- Basic Science
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
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.
Outcomes
Primary Outcomes
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)
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
Time Frame: 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.
Time Frame: 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).
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)
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
Time Frame: 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
Time Frame: 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.
Secondary Outcomes
No secondary outcomes reported