NCT05406349 · Boston University Charles River Campus
Neural Mechanisms of Spatial Representations Beyond the Self
What this study is about
Spatial navigation is a fundamental human behavior, and deficits in navigational functions are among the hallmark symptoms of severe neurological disorders such as Alzheimer's disease. Understanding how the human brain processes and encodes spatial information is thus of critical importance for the development of therapies for affected patients.
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Spatial navigation is a fundamental human behavior, and deficits in navigational functions are among the hallmark symptoms of severe neurological disorders such as Alzheimer's disease. Understanding how the human brain processes and encodes spatial information is thus of critical importance for the development of therapies for affected patients. Previous studies have shown that the brain forms neural representations of spatial information, via spatially-tuned activity of single neurons (e.g., place cells, grid cells, or head direction cells), and by the coordinated oscillatory activity of cell populations. The vast majority of these studies have focused on the encoding of self-related spatial information, such as one's own location, orientation, and movements. However, everyday tasks in social settings require the encoding of spatial information not only for oneself, but also for other people in the environment. At present, it is largely unknown how the human brain accomplishes this important function, and how aspects of human cognition may affect these spatial encoding mechanisms. This project therefore aims to elucidate the neural mechanisms that underlie the encoding of spatial information and awareness of others. Specifically, the proposed research plan will determine how human deep brain oscillations and single-neuron activity allow us to keep track of other individuals as they move through our environment. Next, the project will determine whether these spatial encoding mechanisms are specific to the encoding of another person, or whether they can be used more flexibly to support the encoding of moving inanimate objects and even more abstract cognitive functions such as imagined navigation. Finally, the project will determine how spatial information is encoded in more complex real-world scenarios, when multiple information sources (e.g., multiple people) are present. To address these questions, intracranial medial temporal lobe activity will be recorded from two rare participant groups: (1) Participants with permanently implanted depth electrodes for the treatment of focal epilepsy through responsive neurostimulation (RNS), who provide a unique opportunity to record deep brain oscillations during free movement and naturalistic behavior; and (2) hospitalized epilepsy patients with temporarily implanted intracranial electrodes in the epilepsy monitoring unit (EMU), from whom joint oscillatory and single-neuron activity can be recorded.
Interventions
BEHAVIORAL
Self-navigation task
Participants will perform a self-navigation task with two experimental conditions: Either they will be asked to walk towards a visible wall-mounted sign, or they will be asked to find and learn a hidden target location within the experimental room.
BEHAVIORAL
Observation task
Participants will sit on a chair in a corner of the room (RNS participants) or watch a video that was recorded from the corner of the room (EMU participants). They will be asked to keep track of another person's location who is walking around the room, and to press a button whenever the other person crosses a previously-learned target location.
Primary outcome measures
Oscillatory power
Time frame: Continuous measurement during task performance on day 1 and all subsequent measurement days (up to 14 days per participant)
It will be measured how the oscillatory power (measurement unit: microvolts-squared) of electrophysiological brain activity, as measured via intracranially implanted electrodes and an electroencephalography recording system, is modulated by task-related behavioral variables (such as the individual's spatial location, head direction, movement speed, or their distance/direction to environmental boundaries).
Oscillatory amplitude
Time frame: Continuous measurement during task performance on day 1 and all subsequent measurement days (up to 14 days per participant)
It will be measured how the oscillatory amplitude (measurement unit: microvolts) of electrophysiological brain activity, as measured via intracranially implanted electrodes and an electroencephalography recording system, is modulated by task-related behavioral variables (such as the individual's spatial location, head direction, movement speed, or their distance/direction to environmental boundaries).
Oscillatory frequency
Time frame: Continuous measurement during task performance on day 1 and all subsequent measurement days (up to 14 days per participant)
It will be measured how the frequency of an oscillation (measurement unit: Hertz), as measured via intracranially implanted electrodes and an electroencephalography recording system, is modulated by task-related behavioral variables (such as the individual's spatial location, head direction, movement speed, or their distance/direction to environmental boundaries).
Firing rate of single neurons
Time frame: Continuous measurement during task performance on day 1 and all subsequent measurement days (up to 14 days per participant)
It will be measured how the firing rate of single neurons (measurement unit: Hertz), as measured via intracranially implanted micro-electrodes and an electrophysiology recording system, is modulated by task-related behavioral variables (such as the individual's spatial location, head direction, movement speed, or their distance/direction to environmental boundaries).
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Between 18 and 70 years of age
- Adequate visual and auditory acuity to allow neuropsychological testing
- Have undergone depth electrode placement for the purpose of epilepsy evaluation/treatment OR have NeuroPace RNS System implanted for epilepsy treatment
Exclusion criteria
- All DSM-V Axis I and II disorders other than nicotine-dependence
- History of brain damage
Where
- Boston, Massachusetts
Collaborators
National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Boston Medical Center
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Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 27, 2026 · Source of record for eligibility and locations