Brain activation during antisaccades in unaffected relatives of schizophrenic patients.
BACKGROUND
Schizophrenia patients have difficulty inhibiting automatic saccades. Many studies have failed to resolve whether healthy first-degree relatives share the same deficit. Measures of brain activity may be more sensitive than behavioral measures. In patients, the saccadic inhibition deficit has been related to impaired frontostriatal functioning. This study attempts to establish whether this abnormality is also present in unaffected relatives of patients.


METHODS
Functional brain images were acquired during prosaccades and antisaccades in 16 control subjects and 16 unaffected siblings of schizophrenia patients using an event-related functional magnetic resonance imaging design. Eye movements were measured during scanning.


RESULTS
The task activated a network of regions corresponding to the oculomotor system. Siblings and control subjects did not differ during execution of prosaccades. During antisaccades, siblings did not activate the caudate nucleus. Siblings and control subjects did not differ on the percentage of antisaccade errors.


CONCLUSIONS
Siblings did not appropriately activate the striatum during antisaccades, similar to what has been reported in patients. Siblings, however, did not make significantly more errors during antisaccades, indicating that they were able to compensate for the inactive caudate. Future research is needed to assess the potential of this striatal deficit as (genetic) risk factor for schizophrenia.
Raemaekers
Mathijs
M
Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands.
Ramsey
Nick F
NF
Vink
Matthijs
M
van den Heuvel
Martin P
MP
Kahn
Rene S
RS
D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D002421:Caudate Nucleus / Q000503:physiopathology; D002540:Cerebral Cortex / Q000503:physiopathology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000503:physiopathology; D009433:Neural Inhibition / Q000502:physiology; D009802:Oculomotor Nerve / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D010641:Phenotype; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D012438:Saccades / Q000235:genetics*; D012559:Schizophrenia / Q000235:genetics* / Q000503:physiopathology; D012565:Schizophrenic Psychology; D012569:Schizotypal Personality Disorder / Q000235:genetics / Q000503:physiopathology; D014793:Visual Cortex / Q000503:physiopathology
D010100:Oxygen