Protocol Number: 05-M-0157

Title:

Top-Down Attentional Control of Visual Processing

Number:

05-M-0157

Summary:

The NIMH is conducting studies aimed at gaining a better understanding of the areas of the brain that are involved in different types of mental processes. This study will focus on brain regions involved in visual perception and attention.

Healthy normal volunteers and people who have had a stroke or undergone neurosurgery may be eligible for this study. Candidates must be 18 years of age or older, They must not have a history of a psychiatric disorder, including depression, anxiety, psychosis, or neurological disease other than stroke or the previous neurosurgery.

Participants undergo the following tests and procedures during four or more visits to the NIH Clinical Center:

-Physical and neurological examinations and depression rating scale.

-Cognitive testing: Subjects complete written tests, sit at a computer and make decisions about what they are shown by pressing keys, or answer questions from a test examiner.

-Behavioral training: Subjects practice performing a cognitive task that involves looking at and making decisions about visual images that appear on a computer screen.

-Magnetic resonance imaging (MRI): Subjects undergo MRI scanning while they perform the task they previously practiced. The MRI scanner is a metal cylinder surrounded by a strong magnetic field. During the procedure, subjects lie still for up to 10 minutes at a time on a table that can slide in and out of the cylinder. The entire MRI scanning session takes about one hour. There are multiple scans which each can take up to 10 minutes. They may be asked to return for one or two additional scanning sessions.

During the behavioral training or MRI scanning, special pieces of equipment that monitor eye movements may be used.

Some subjects may be asked to return to NIH for an additional visit to participate in a magnetoencephalographic scan. This test uses several sensors applied to the scalp to measure very small changes in magnetic fields. This is another way to measure brain activity.

Sponsoring Institute:

National Institute of Mental Health (NIMH)

Recruitment Detail

Type: Participants currently recruited/enrolled

Gender: Male & Female

Referral Letter Required: No

Population Exclusion(s): Children

Eligibility Criteria:

INCLUSION CRITERIA:

ALL SUBJECTS -

All subjects will be volunteers and be 18 years of age or older.

PATIENTS -

Subjects with unilateral or bilateral lesions of prefrontal or parietal cortex will be selected for participation in the behavioral and brain-imaging studies described within this protocol.

Control subjects with unilateral or bilateral lesions of temporal cortex will also be studied.

Finally, patients with amygdala lesions will also be studied to test the specific hypothesis outlined in Experiment 4.

In order to obtain a sufficient number of focal lesion patients representative of different brain regions, patients with different etiologies will be studied, provided the damage is circumscribed.

The main etiologies that we will consider are stroke, lobectomy, and tumor.

We will restrict groups to include patients with the same etiology, lesion location, and lesion volume. Lesion location will consider the two hemispheres separately.

Patients who also have non-amygdala subcortical lesions will be grouped separately from patients with cortical-only lesions.

Our goal is to not group patients with more focal brain lesions compromising a single region (e.g., middle frontal gyrus) with patients with more massive damage (e.g., large extents of superior, middle, and inferior frontal gyrus).

Focal lesion patients will not be excluded on the basis of medication.

NORMAL VOLUNTEERS -

Neurologically normal, age-matched volunteers will be recruited from the local community through normal Clinical Center channels.

EXCLUSION CRITERIA:

The following criteria will be used to exclude patients or healthy volunteers from participation in this study:

- Patients with language impairments that prevent them from understanding our tasks or follow instructions will be excluded.

- Patients with a WAIS-R Full-Scale IQ of less than 75 will be excluded.

- Patients with severe cognitive dysfunction as assessed by the neuropsychological tests.

- Subjects with moderate or severe depression as assessed by the Beck Depression Inventory (scores greater than 18).

- Patients who cannot perform control tasks to the same level of performance as the control subjects will be excluded.

- Subjects with contraindication to MRI scanning will be excluded from any testing which involves the use of MRI. These contraindications include subjects with the following devices or conditions: a) central nervous system aneurysm clips; b) implanted neural stimulator; c) implanted cardiac pacemaker or defibrillator; d) cochlear implant; e) ocular foreign body (e.g., metal shavings); f) insulin pump; g) metal shrapnel or bullet; h) any implanted device that is incompatible with MRI.

- Subjects with a history of any neurological or psychiatric disorder not related to the focal lesion (e.g., epilepsy, schizophrenia, etc.)

- Subjects with any previous head injuries not related to the focal lesion.

- Subjects with a history of drug or alcohol abuse or addiction (determined by a qualified neurologist/psychiatrist).

- Subjects with conditions that preclude entry into the scanner (e.g., morbid obesity, claustrophobia, etc.) will not be included in brain imaging studies.

- Female subjects of child-bearing age will be excluded from brain imaging studies if they are pregnant or refuse to undergo a urine pregnancy test.

- Subjects with visual, auditory, motor, or language problems that would prohibit them from being able to properly perform the visual attention tasks, to understand instructions, indicate their responses, or to communicate with the experimenter via an intercom system.

- Subjects who have undergone radiation treatment or chemotherapy during a one-year period prior to the experiment.

Special Instructions:

Currently Not Provided

Keywords:

Attention

Executive Function

Vision

fMRI

Top-Down

Visual Processing

Lesion

Prefrontal

Parietal

Recruitment Keyword(s):

Focal Brain Lesion

Healthy Volunteer

Condition(s):

Focal Lesions

Focal Brain Lesion

Investigational Drug(s):

None

Investigational Device(s):

None

Intervention(s):

None

Supporting Site:

National Institute of Mental Health

Contact(s):

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

Citation(s):

Anderson AK, Phelps EA. Lesions of the human amygdala impair enhanced perception of emotionally salient events. Nature. 2001 May 17;411(6835):305-9.

Barcelo F, Suwazono S, Knight RT. Prefrontal modulation of visual processing in humans. Nat Neurosci. 2000 Apr;3(4):399-403.

Bechara A, Damasio H, Damasio AR. Emotion, decision making and the orbitofrontal cortex. Cereb Cortex. 2000 Mar;10(3):295-307. Review.

• Questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.
• Technical questions regarding the Clinical Center web site, please contact the Department of Networks and Applications, CC.

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