Eye Blink Response in Healthy Volunteers and Adults With Schizophrenia

Launched by NATIONAL INSTITUTE OF MENTAL HEALTH (NIMH) · Nov 3, 1999

Keywords

ClinConnect Summary

Eyeblink conditioning is a paradigm that allows the study of aspects of the neural mechanism of memory in humans. This paradigm has been extensively studied in animals and human beings and its functional neuroanatomy appears to be well understood, involving the hippocampus and cerebellum. The performance on this task is most likely independent of subject motivation. Moreover, manipulation of the intervals between conditioned and unconditioned stimuli allows to study subliminal forms of mnemonic encoding ("delay" task) as well as learning that is associated with conscious awareness ("trace" ...

Gender

ALL

Eligibility criteria

• • INCLUSION CRITERIA
• Controls:
• • No psychiatric or severe chronic medical illness at the time of the study, and by history. This includes the absence of substance abuse histories, learning disabilities and all DSM IV disorders. Medical histories will be evaluated by the investigators and medical conditions that are judged not to interfere with the study may be allowed.
• • No use of psychotropic substances in the last 3 months.
• • Age 18-60.
• • No family history of schizophrenia by subject report and possibly also by collateral report by at least one other family member.
• Patients:
• • Schizophrenia, any subtype or schizoaffective disorder, depressed type by DSM IV (110).
• • Only concomitant medications should be neuroleptics and medications directed at controlling side effects (e.g. anticholinergics). An effort will be made to recruit patients on atypical neuroleptics, therefore attempting to minimize the anticholinergics, which might interfere with the acquisition of a conditioned response. When patients on anticholinergic treatment will be recruited as inpatients, a clinical evaluation of the risks and benefits of suspending anticholinergic treatment will be made and discussed with the patient. Anticholinergics will be withdrawn for a period equivalent to 3 half lives of the drug before attempting the study, if this is judged to be achievable with a relatively low risk and the patient agrees.
• • Age18-60.
• • EXCLUSION CRITERIA
• Controls and Patients:
• • Impaired hearing.
• • Use of caffeine or tobacco in the 2 hours preceding the test.
• • Head trauma with loss of consciousness in the last year, or any evidence of functional impairment due to and persisting after head trauma.
• • All subjects who are unable to withstand the eyeblink testing will be excluded. Subjects who are not able to participate in the MRI (e.g. due to claustrophobia) will be studied to achieve a larger group for the behavioral experiments.
• • Subjects who are found to have eye lesions on exam.
• • Patients or healthy volunteers with a known risk from exposure to high magnetic fields (e.g. patients with pace makers) and those who have metallic implants (e.g. braces) in the head region (likely to create artifact on the MRI scans) will be excluded from participating in the MRI studies.
• Patients:
• • Coexistence of another major mental illness at the time of the study. If the patients experienced other mental illnesses in the past (e.g. a learning disability or major depression), then this should be judged to be fully recovered.
• • Criteria for substance abuse met in the last 6 months.
• • Criteria for substance dependence met in the last year. If criteria for dependence were met in the past, then the duration of the disorder was less than 3 years, or not judged to have produced long term brain changes to allow the patient to be in the study.
• • Major concurrent medical illness likely to interfere with the acquisition of the task.
• • Concomitant medications which could interfere with performance on the task, excluding neuroleptics.
• • Presence of diskinetic movements of the face and tongue (likely to interfere with eyeblink measures, or of gross involuntary movements of the whole body (likely to interfere with positioning in the MRI scanner).
• • Pregnancy testing will be performed on women of childbearing age within the three days prior to MRI scanning.
• Siblings of Patients with Schizophrenia:
• • The same inclusion criteria as normal volunteers, with the exception of family history, of course. In addition, the inclusion criteria for protocol #95-M-0150 will apply.
• • The same exclusion criteria as normal volunteers will apply.