Neural correlates of refixation saccades and antisaccades in normal and schizophrenia subjects.
BACKGROUND
Schizophrenia subjects demonstrate difficulties on tasks requiring saccadic inhibition, despite normal refixation saccade performance. Saccadic inhibition is ostensibly mediated via prefrontal cortex and associated cortical/subcortical circuitry. The current study tests hypotheses about the neural substrates of normal and abnormal saccadic performance among subjects with schizophrenia.


METHODS
Using functional magnetic resonance imaging, blood oxygenation level-dependent (BOLD) data were recorded while 13 normal and 14 schizophrenia subjects were engaged in refixation and antisaccade tasks.


RESULTS
Schizophrenia subjects did not demonstrate the increased prefrontal cortex BOLD contrast during antisaccade performance that was apparent in the normal subjects. Schizophrenia subjects did, however, demonstrate normal BOLD contrast associated with refixation saccade performance in the frontal and supplementary eye fields, and posterior parietal cortex.


CONCLUSIONS
Results from the current study support hypotheses of dysfunctional prefrontal cortex circuitry among schizophrenia subjects. Furthermore, this abnormality existed despite normal BOLD contrast observed during refixation saccade generation in the schizophrenia group.
McDowell
Jennifer E
JE
Department of Psychiatry, University of California, San Diego, La Jolla, California 92093-0804, USA.
Brown
Gregory G
GG
Paulus
Martin
M
Martinez
Antigona
A
Stewart
Sara E
SE
Dubowitz
David J
DJ
Braff
David L
DL
D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017397:Prefrontal Cortex / Q000378:metabolism* / Q000503:physiopathology*; D011569:Psychiatric Status Rating Scales; D012438:Saccades / Q000502:physiology*; D012559:Schizophrenia / Q000175:diagnosis* / Q000503:physiopathology*; D014055:Tomography, Emission-Computed; D014794:Visual Fields / Q000502:physiology