Memory-guided saccade abnormalities in schizophrenic patients and their healthy, full biological siblings.
BACKGROUND
Ocular-motor inhibition errors and saccadic hypometria occur at elevated rates in biological relatives of schizophrenic patients. The memory-guided saccade (MS) paradigm requires a subject to inhibit reflexive saccades (RSs) and to programme a delayed saccade towards a remembered target.


METHODS
MS, RS, and central fixation (CF) tasks were administered to 16 patients who met the criteria for DSM-IV schizophrenia, 19 of their psychiatrically healthy siblings, and 18 controls.


RESULTS
Patients and siblings showed elevated MS error rates reflecting a failure to inhibit RSs to a visible target, as required by the task. In contrast to controls, prior errors did not improve MS accuracy in patients and siblings.


CONCLUSIONS
The specific characteristics of the elevated MS error rate help to clarify the nature of the disinhibition impairment found in schizophrenics and their healthy siblings. Failure to inhibit premature saccades and to improve the accuracy of subsequent volitional saccades implicates a deficit in spatial working-memory integration, mental representation and/or motor learning processes in schizophrenia.
Landgraf
S
S
INSERM U796, Physiopathology of Psychiatric Diseases, University Paris René Descartes, Faculty of Medicine, Sainte Anne Hospital, Paris, France. landgras@cms.hu-berlin.de
Amado
I
I
Bourdel
M-C
MC
Leonardi
S
S
Krebs
M-O
MO
D000328:Adult; D001288:Attention; D005260:Female; D005403:Fixation, Ocular; D020022:Genetic Predisposition to Disease / Q000235:genetics / Q000523:psychology; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008570:Memory, Short-Term; D009039:Motion Perception; D009949:Orientation; D010364:Pattern Recognition, Visual; D010641:Phenotype; D011930:Reaction Time; D012438:Saccades / Q000235:genetics*; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics*; D012565:Schizophrenic Psychology; D012569:Schizotypal Personality Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology