Exploring the Relationship Between Brain Asymmetry and Attention

Background:

People tend to pay more attention to one side of space than the other and this may be due to differences in the structure and function of the two sides of the brain. We are interested in whether we can detect those difference with magnetic resonance imaging (MRI), transcranial magnetic stimulation (TMS), and electroencephalography (EEG).

Objective:

The purpose of the study is to understand how differences in brain structure may cause people to pay more attention to one side than the other.

Eligibility:

Healthy adults ages 18-35

Design:

Participants will be screened with a neurological exam.

Participants will have 2-3 visits for a total duration of about 7/8 hours.

Women of childbearing age must have a negative pregnancy test before each MRI scan.

Visits may include:

Physical exam

Tests of attention, and thinking

TMS. A brief electrical current will pass through a wire coil on the scalp. Participants will hear a click and may feel a pull. They may be asked to tense muscles or do tasks.

Magnetic resonance imaging (MRI) scan for a maximum of 1 hour. Participants will lie on a table that slides into a cylinder in a strong magnetic field. They will do tasks on a computer screen or lie still. They will get earplugs for loud noise.

EEG for no longer than 5 hours, with most lasting 3 hours. Gel and a cap with electrodes will be placed on the scalp. They will record brain waves while the participant gets TMS or does nothing.

Questions about participants dominant hand and about the MRI.

Study Overview

• Status: Completed
• Conditions: Normal Physiology
• Intervention / Treatment: Device: TMS EEG; Device: TMS fMRI

Detailed Description

Objective

The goal of this protocol to explore correlations between lateralized individual differences in visual attentional preference and hemispheric asymmetries in functional connectivity between the frontal and parietal visual attention areas. To measure functional connectivity, resting state functional MRI and electroencephalographic (EEG) potentials evoked with transcranial magnetic stimulation (TMS) will be used. Protocol research will also attempt to validate the TMS-evoked EEG potentials against fMRI resting state functional connectivity.

Study Population

Up to 80 right-handed and right-eyed healthy volunteers, aged 18-35

Design

TMS evoked EEG potentials (TEPs) and fMRI will be used to measure functional connectivity between the posterior parietal cortex and the frontal visual attention area. Various tasks will be used to quantify attention and explore their relationship with asymmetries in functional connectivity. A qualitative comparison between the value of fMRI and TEPs for predicting attentional bias will be made.

Outcome Measures

• Behavioral measures of attention
• TEP measures of functional connectivity
• fMRI measures of functional connectivity

• Study Type: Interventional
• Enrollment (Actual): 45
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Bethesda, Maryland, United States, 20892
      • National Institutes of Health Clinical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

• INCLUSION CRITERIA:
• Age 18 and older
• Able to provide consent

For some sub-studies, we may limit participation by handedness or eye dominance.

EXCLUSION CRITERIA:

• Any current major neurological or psychiatric disorder, such as, (but not limited to) stroke, Parkinson disease, Alzheimer disease, schizophrenia or major depression
• Findings on neurological examination indicative of significant brain disease
• Individuals with significant health problems, such as cardiovascular disease, malignancy, or connective tissue disorder
• History of seizure, defined as a diagnosis by a health care provider of one or more epileptic seizures or an anecdotal history which, in the opinion of the PI, is suggestive of epileptic seizure. Any individual who answers other than negatively to the question, Have you ever had an epileptic seizure on screening will be questioned directly by the PI
• Current oral use of a medication that lowers the seizure threshold such as neuroleptics, beta lactams, isoniazid, metronidazole, tricyclic or other antidepressants, or prescription stimulants
• Individuals regularly taking medications that cause significant psychomotor activation or depression, e.g., stimulants and CNS depressant drugs such as benzodiazepines, will be excluded.
• For MRI studies: Any metal in the body which would make having an MRI scan unsafe, such as pacemakers, stimulators, pumps, aneurysm clips, metallic prostheses, artificial heart valves, cochlear implants or shrapnel fragments, any individual who was a welder or metal worker. Participants will also be excluded if they are uncomfortable in small closed spaces (i.e. claustrophobia) or are not able to lie comfortably on their back for up to two hours
• Pregnancy or plans to become pregnant in the next two months
• Members of the Behavioral Neurology Unit, NINDS
• Use of illegal drugs in the past year
• Consumption of more than 7 alcoholic drinks a week for females or 14 alcoholic drinks a week for males.

There is no general exclusion for NIH employees. Inclusion/exclusion criteria will be checked before enrollment in each sub-study to ensure that participants remain eligible.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Healthy Volunteers; thematic permission to use non-invasive techniques regarded as having minimal risk in healthy individuals, such as, MRI, EEG, EMG, low-frequency stimulation (= 1 Hz), electrical stimulation of the skin to mimic the somatosensory artifact of TMS, and behavioral tests	Device: TMS EEG; attempt to use TMS EEG to measure connectivity between cortical areas; Device: TMS fMRI; compare measurements to established functional connectivity measures; e.g., EEG coherence and fMRI

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Exploratory sub-studies under this protocol will answer questions about how to optimize EEG recordings of the cortical response to TMS.	Response to TMS	20 visits

Collaborators and Investigators

• Sponsor: National Institute of Neurological Disorders and Stroke (NINDS)

Publications and helpful links

Helpful Links

• NIH Clinical Center Detailed Web Page

Study record dates

Study Major Dates

• Study Start (Actual): February 28, 2019
• Primary Completion (Actual): October 24, 2022
• Study Completion (Actual): October 24, 2022

Study Registration Dates

• First Submitted: December 27, 2018
• First Submitted That Met QC Criteria: December 27, 2018
• First Posted (Actual): December 28, 2018

Study Record Updates

• Last Update Posted (Actual): October 26, 2022
• Last Update Submitted That Met QC Criteria: October 25, 2022
• Last Verified: October 24, 2022

More Information

Terms related to this study

• Keywords: Behavior; fMRI; TMS; Electroencephalogram (EEG); TMS-Evoked Potential
• Other Study ID Numbers: 190036; 19-N-0036

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided
• IPD Plan Description: .Data sharing at an independent subject level may not be feasible.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No