Basic Experimental Study of Hippocampal Memory Functions

Summary

This project tests the role of the human hippocampus in providing online representation of episodic content and providing the top-down signals to brain networks for visuospatial attention and visual processing needed to drive visual sampling for the formation of coherent episodic memories. This hypothesis will be tested in several experiments that measure and manipulate hippocampal activity within eye-tracking tasks designed to isolate the interplay between memory and visual sampling during memory formation. These experiments will be performed in individuals with epilepsy undergoing neurosurgical procedures as part of clinical care, as this provides invasive recordings of neural activity (intracranial electroencephalography, or "iEEG") from the hippocampus and other regions of interest with temporal resolution that matches the rapid pace of eye movements. The temporal resolution of iEEG is key to addressing the hypotheses concerning how the hippocampus drives visual sampling, in addition to responding to it. Direct electrical stimulation through the iEEG electrodes will also be used to test the necessary role of hippocampal processing in driving active visual sampling. By rigorously testing the role of hippocampus in interaction with large-scale networks during the process of memory formation that occurs via active sampling, this project aims to better understand mechanisms relevant to the disruptions of memory formation that occur in neurological and psychiatric disorders.

Conditions

• Memory

Interventions

BEHAVIORAL

Different cognitive and memory demands during the memory experiment

Study conditions will involve attempting to memorize visual scenes, attempting to memorize arrays of visual objects, viewing in a self-directed manner, viewing in a passive other-directed manner, and making memory judgments about whether stimuli are studied versus novel.

OTHER

Different electrical stimulation parameters during cognitive and memory demands

Study conditions will involve different parameters for electrical stimulation delivered through iEEG electrodes, including the presence of stimulation (no stimulation versus stimulation) and the location of stimulation (hippocampus versus amygdala).

Sponsors & Collaborators

• National Institute of Mental Health (NIMH)

  collaborator NIH

• University of Chicago

  lead OTHER

Principal Investigators

• Joel Voss, PhD · University of Chicago

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

45 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2023-01-16

Primary Completion

2027-04-30

Completion

2027-06-30

Countries

• United States

Study Locations