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 Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
800
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.
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
To use direct electrical stimulation to disentangle causal versus correlative biomarkers of verbal and spatial episodic memory
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
Time frame: Up to 4 weeks (typical duration of hospital stay)
To develop and test models of human brain dynamics in the presence of electrical stimulation
2\. We will compare spectral indices of brain activity before and after stimulation as a function of stimulation parameters.
Time frame: Up to 4 weeks (typical duration of hospital stay)
To assess how reactivation of prior memories shapes subsequent recall and memory organization, including memory for the content, context and value of experiences.
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).
Time frame: Up to 4 weeks (typical duration of hospital stay)
To determine whether state-dependent stimulation can separately be used to modulate encoding and retrieval processes
4\. We will evaluate the closed-loop stimulation protocol described in Kahana et al. (2023) in both encoding and retrieval.
Time frame: Up to 4 weeks (typical duration of hospital stay)
To determine whether stimulation is more effective at modulating memory when targeted to regions with specific connectivity profiles to the medial temporal lobe
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.
Time frame: Up to 4 weeks (typical duration of hospital stay)
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Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States
Mayo Clinic
Rochester, Minnesota, United States
Dartmouth-Hitchcock Medical Center
Lebanon, New Hampshire, United States
Columbia University
New York, New York, 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
...and 1 more locations
To determine how simultaneous stimulation at multiple target sites can be optimized to modulate memory
6\. We will compare recall rates during a free recall experiment with no brain stimulation, stimulation at one site, and stimulation at multiple sites.
Time frame: Up to 4 weeks (typical duration of hospital stay)