Protocol Number: 04-N-0117

Title:

Modulation of the Visual Information Processing in the Human Parieto-Frontal Network as Studied by a Frequency Tagging Technique During Visuomotor Tracking

Number:

04-N-0117

Summary:

This study will examine how the brain works when people look at an object, follow a moving object with their eyes, and reach out their hand to an object. Different areas of the brain work together in reaching out a hand to an object. These areas are also important for concentrating on objects or following them with the eyes. This study will use magnetoencephalography (MEG) to observe more precisely how discrete parts of the brain work during these movements. MEG is a new technique for recording magnetic field changes produced by brain activity.

Healthy normal volunteers 20 years of age and older who are right-handed and who have no history of brain or eye disease may be eligible for this study. Candidates will be screened with a medical history and brief physical examination. They will complete questionnaires for MEG screening and for determining handedness.

Participants undergo MEG recording and magnetic resonance imaging (MRI). For MEG, the subject sits comfortably in front of a computer screen, and a cone containing magnetic field detectors is lowered onto the head. Electrodes are placed on both sides of the outer part of the eyelids and just above and below the left eye to monitor eye movement. During MEG, subjects perform the following tasks:

1. Eye fixation: A small white cross and a white ring appear on the center of the computer screen. Another white ring moves slowly around the screen in random fashion. Subjects keep their eyes fixed on the central cross and concentrate on the ring at the center, ignoring the moving ring.

2. Ocular tracking: The same cross and rings in task 1 appear on the screen, but in this task the subjects follow the moving ring with their eyes and ignore the cross and ring in the center.

3. Peripheral manual tracking task (right hand): In addition to the cross and rings in task 1, a small white disc-shaped cursor appears on the screen. Using their right hand, subjects use a joystick to move the cursor as precisely as possible to follow the moving ring, while keeping their eyes fixed on the central cross.

4. Peripheral manual tracking task (left hand): The same as task 3, except using the left hand.

5. Central manual tracking: The cross, rings, and joystick are the same as in task 3. Subjects move the cursor to follow the moving ring as precisely as possible, while following the moving ring with their eyes and ignoring the cross and ring in the center of the screen.

Subjects practice each task before MEG recording starts. Then they perform each task twice in random order, with a 1- or 2-minute break between tasks.

Subjects who do not have previous MRI images filed in NINDS's database undergo MRI scanning. MRI uses a strong magnetic field and radio waves to obtain images of body organs and tissues. The scanner is a metal cylinder surrounded by a strong magnetic field. Subjects lie still on a table that can slide in an out of the cylinder. They can communicate with the MRI staff at all times during the procedure.

Sponsoring Institute:

National Institute of Neurological Disorders and Stroke (NINDS)

Recruitment Detail

Type: Active Accrual Of New Subjects

Gender: Male & Female

Referral Letter Required: Yes

Population Exclusion(s): Children

Eligibility Criteria:

INCLUSION CRITERIA:

The subjects must be 20 years old or older and right-handed as screened by Edinburgh handedness inventory.

They must be healthy and have no known history of neurological or ophthalmological diseases.

EXCLUSION CRITERIA:

Subjects under the age of 20 will be excluded from this study.

Subjects who match the criteria below will be excluded from this study due to human subject protection and because they may negatively affect the MEG data quality.

Subjects wearing glasses.

Subjects with involuntary movement or dyskinesia.

Subjects with spontaneous nystagmus.

Subjects who can not execute the eye or manual tracking after sufficient practice time.

Subjects with metal objects in the body.

Subjects with history of severe head trauma.

Pregnant women.

Special Instructions: Currently Not Provided

Keywords:

Visual Feedback

Cortical Connectivity

Magnetoencephalography

Eye Tracking

Recruitment Keywords:

Healthy Volunteer

HV

Conditions:

Healthy

Investigational Drug(s):

None

Investigational Device(s):

None

Contacts:

Patient Recruitment and Public Liaison Office
Building 61
10 Cloister Court
Bethesda, Maryland 20892-4754
Toll Free: 1-800-411-1222
TTY: 301-594-9774 (local),1-866-411-1010 (toll free)
Fax: 301-480-9793

Electronic Mail:prpl@mail.cc.nih.gov

Citations:

Nagaratnam N, Grice D, Kalouche H. Optic ataxia following unilateral stroke. J Neurol Sci. 1998 Mar 5;155(2):204-7. PMID: 9562268

Perenin MT, Vighetto A. Optic ataxia: a specific disruption in visuomotor mechanisms. I. Different aspects of the deficit in reaching for objects. Brain. 1988 Jun;111 ( Pt 3):643-74. PMID: 3382915

Glover S. Optic ataxia as a deficit specific to the on-line control of actions. Neurosci Biobehav Rev. 2003 Aug;27(5):447-56. Review. PMID: 14505686

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