N100 and P300 amplitude to Go and No-Go variants of the auditory oddball in siblings discordant for schizophrenia.
BACKGROUND
P300 amplitude reduction is reliably seen in schizophrenia. Inconsistent reports of isolated frontal and/or parietal deficits in unaffected family members may be clarified using a task that places greater load on frontal function.


METHODS
Go and No-Go versions of the auditory oddball task were performed by eighteen schizophrenia patients, age-matched unaffected siblings and healthy controls matched closely to unaffected siblings on age, sex, education, socioeconomic-status, handedness and ethnicity. Groups were compared on P300 and N100 amplitude and latency. Spearman correlations were used to test the relationship between ERP amplitudes and neuropsychological measures of executive function and memory. The relationship between schizotypy--as measured using the structured interview--and ERPs was explored in a combined group of siblings and controls.


RESULTS
Independent of task, patients had lower P300 than controls and reduced parietal amplitude compared to siblings. Siblings had enhanced frontocentral N100 compared to controls. No-Go P300 amplitude and N100 latency was associated with executive function measures. There were significant intraclass correlations between patients and siblings for No-Go P300 amplitude, particularly at the central midline electrode. Frontocentral N100 and P300 amplitude were positively correlated with anxiety-related aspects of schizotypy.


CONCLUSIONS
Enhanced N100 is present in unaffected siblings. Parietal P300 is intact in unaffected siblings, but reduced in patients. The No-Go-oddball is more sensitive than the Go-oddball to executive function deficits in patients and as an index of heritability.
Sumich
Alex
A
King's College London, Institute of Psychiatry, BIAU, Centre for Neuroimaging Sciences, London SE5 8AF, UK. a.sumich@iop.kcl.ac.uk
Kumari
Veena
V
Dodd
Phillipa
P
Ettinger
Ulrich
U
Hughes
Catherine
C
Zachariah
Elizabeth
E
Sharma
Tonmoy
T
D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D016000:Cluster Analysis; D004569:Electroencephalography / Q000706:statistics & numerical data; D018913:Event-Related Potentials, P300 / Q000235:genetics / Q000502:physiology; D005071:Evoked Potentials / Q000235:genetics / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000235:genetics / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D010296:Parietal Lobe / Q000503:physiopathology; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011930:Reaction Time / Q000235:genetics / Q000502:physiology; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D035781:Siblings / Q000523:psychology*