Brain Stimulation and Visually-guided Navigation

Not Applicable

Terminated

Conditions: Healthy Participants

Interventions: Device: Repetitive Transcranial Magnetic Stimulation (rTMS)

Registration Number: NCT04961645

Lead Sponsor: Emory University

Brief Summary: This study investigates the neural mechanisms causally involved in how people navigate through their immediately visible environment (e.g., walking around one's bedroom flawlessly and effortlessly, not bumping into the walls or furniture). To investigate whether particular neural mechanisms are causally involved in "visually-guided navigation", repetitive transcranial magnetic stimulation (rTMS) is used to temporarily disrupt the functioning of particular brain regions in healthy adults while they are shown simple visual stimuli of places (e.g., bedrooms, kitchens, and living rooms) and asked to perform simple computer tasks or to complete simple behavioral tasks.

Detailed Description: Human ability to navigate through the immediately visible environment is crucial for survival. However, the representations and computations underlying this remarkable ability are not well understood, and current computer vision algorithms (robots) still lag far behind human performance. One promising strategy for attempting to understand "visually-guided navigation" is to characterize the neural systems that accomplish it. The results from functional magnetic resonance (fMRI) on adult humans have begun to elucidate the cortical regions involved in visually-guided navigation, with the central finding that there is at least one visual cortical region - called the occipital place area (OPA) that may play a central role in the ability to navigate through currently visible places (e.g., walking around our bedroom flawlessly and effortlessly, not bumping into the walls or furniture our bedroom). However, fMRI is a correlational method, and research still needs to determine if this functionally specific brain region is causally involved in visually-guided navigation. Understanding the causal involvement of this region will provide important clues about how humans navigate their world, and also perhaps someday be harnessed to help those individuals who devastatingly lose the ability to navigate, as a result of eye diseases, brain surgery, stroke, neurodegenerative diseases, or developmental disorders.

The use of rTMS to investigate the causal involvement of particular brain regions in particular human abilities is not novel, having been used to investigate face recognition, scene recognition, and object recognition. The general question for this research is to determine, using rTMS, the causal involvement of OPA in visually-guided navigation.

Participants will have an fMRI scan to identify the OPA location in each individual participant. Once the OPA location is known, participants will receive the rTMS study intervention.

Recruitment & Eligibility

Status: TERMINATED

Sex: All

Target Recruitment: 11

Inclusion Criteria

Normal or corrected-to-normal vision

Exclusion Criteria

Metal in the body
Personal or first-degree family history of epileptic seizure
A known brain injury
Claustrophobia
Taking certain medications that may increase the risk of seizures (e.g., bupropion, varenicline, chlorpromazine, theophylline) or reduce the effects of rTMS, such as benzodiazepines
Adults who are unable to consent, pregnant women, and prisoners

Study & Design

Study Type: INTERVENTIONAL

Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
Repetitive Transcranial Magnetic Stimulation (rTMS)	Repetitive Transcranial Magnetic Stimulation (rTMS)	Participants will have two study visits. During the first visit, participants will have an fMRI scan to identify the OPA location in each individual participant. During the second visit, participants will receive rTMS. Each visit lasts approximately 90 minutes.

Primary Outcome Measures

Name	Time	Method
Accuracy During Visually-guided Navigation Computer-based Task	During rTMS of control site and during rTMS of OPA, on Day 1	To assess performance during the visually-guided navigation computer-based task, rTMS is applied to to the control vertex site, which is not implicated in visually-guided navigation, as well as the occipital place area (OPA) site. While participants are shown simple visual stimuli of places (e.g., bedrooms, kitchens, and living rooms) they are asked to perform simple computer-based tasks (e.g., imagine they are walking through the room, and respond via button press whether they can leave through a door on the left, center, or right wall, as indicated by a continuous path on the floor). Performance is measured in task accuracy (the percentage of tasks performed correctly). A decrease in performance on the visually-guided navigation task only after rTMS is applied to OPA (but not vertex) indicates causal involvement of OPA in visually-guided navigation.
Reaction Time During Visually-guided Navigation Computer-based Task	During rTMS of control site and during rTMS of OPA, on Day 1	To assess performance during the visually-guided navigation computer-based task, rTMS is applied to to the control vertex site, which is not implicated in visually-guided navigation, as well as the occipital place area (OPA) site. While participants are shown simple visual stimuli of places (e.g., bedrooms, kitchens, and living rooms) they are asked to perform simple computer-based tasks (e.g., imagine they are walking through the room, and respond via button press whether they can leave through a door on the left, center, or right wall, as indicated by a continuous path on the floor). Performance is measured in the time (in milliseconds) that it takes to complete the task correctly. A decrease in performance on the visually-guided navigation task only after rTMS is applied to OPA (but not vertex) indicates causal involvement of OPA in visually-guided navigation.
Accuracy During Visually-guided Navigation Behavioral-based Task	During rTMS of control site and during rTMS of OPA, on Day 1	To assess performance during the visually-guided navigation behavior-based task, rTMS is applied to to the control vertex site, which is not implicated in visually-guided navigation, as well as the occipital place area (OPA) site. Participants are asked to complete simple behavioral-based tasks (e.g., actually walk around a small room and search for hidden objects). Performance is measured in task accuracy (the percentage of tasks performed correctly). A decrease in performance on the visually-guided navigation task only after rTMS is applied to OPA (but not vertex) indicates causal involvement of OPA in visually-guided navigation.
Reaction Time During Visually-guided Navigation Behavioral-based Task	During rTMS of control site and during rTMS of OPA, on Day 1	To assess performance during the visually-guided navigation behavioral-based task, rTMS is applied to to the control vertex site, which is not implicated in visually-guided navigation, as well as the occipital place area (OPA) site. Participants are asked to complete simple behavioral tasks (e.g., actually walk around a small room and search for hidden objects). Performance is measured as the time (in milliseconds) that it takes to complete the task correctly. A decrease in performance on the visually-guided navigation task only after rTMS is applied to OPA (but not vertex) indicates causal involvement of OPA in visually-guided navigation.