Oculomotor and Spatial Cognition Deficits in Schizophrenia

DESCRIPTION: (Verbatim from the Applicant's Abstract) Abnormalities of eye movement control
and spatial cognition are well-established deficits in schizophrenia. However, the regional
disturbances in brain function causing these deficits are not yet known. This application
proposes a series of integrated behavioral and fMRI studies designed to identify causes of
pursuit eye movement and spatial working memory deficits in schizophrenia. The investigators
will determine whether there are intrinsic functional disturbances in extrastriate regions
that process visual motion information (Area MT) using both optic flow and motion
aftereffect paradigms. The investigaotrs will parametrically manipulate attentional
enhancements during pursuit tracking to clarify the causes of what appears to be a reduced
influence of extra retinal signals on the control of pursuit eye movements in schizophrenia.
The investigators will use an oculomotor delayed response (ODR) task to study spatial
working memory impairments in schizophrenia. The investigators will parametrically
manipulate the rate of "distractor" information presented during the delay period of this
prototypic spatial working memory task in order to model changes in dorsal brain regions of
interest across a range of processing load conditions. Fifty schizophrenic patients will be
recruited, 25 first episode antipsychotic-naive patients and 25 unmedicated chronic patients
in addition to matched healthy subjects. Subjects will be restudied after 3 weeks, during
which all patients will receive controlled treatment, in order to assess the extent of
normalization of brain function associated with treatment and clinical recovery. The results
of these studies will clarify the neurobiological basis of one of the most robust and
promising biological markers of risk for schizophrenia, and of working memory disturbances
known to be a prominent component of the neuropsychological profile of the disorder.
Findings will also clarify the diagnostic specificity of regional brain disturbances causing
these abnormalities, and the impact of known effective treatments upon them.