Levels-of-processing effects in first-degree relatives of individuals with schizophrenia.
BACKGROUND
First-degree relatives of individuals with schizophrenia show cognitive impairments that are similar to but less severe than their ill relatives. We have shown that memory impairments can be improved and prefrontal cortical (PFC) activity increased in individuals with schizophrenia by providing beneficial encoding strategies. The current study used a similar paradigm to determine whether siblings of individuals with schizophrenia (SIBs) also show increases in brain activity when presented with beneficial encoding strategies.


METHODS
Twenty-one SIBs and 38 siblings of healthy comparison subjects underwent functional magnetic resonance imaging scans while engaged in deep (abstract/concrete judgments) and shallow (orthographic judgments) encoding. Subjects were then given a recognition memory test.


RESULTS
The groups did not differ on encoding or recognition accuracy, and the SIBs benefited from deep encoding to a similar degree as control subjects. The SIBs showed deep encoding-related activity in a number of PFC regions typically activated during semantic processing. However, SIBs showed more activity than control subjects in three subregions of PFC (left BA 44 & BA 47 bilaterally).


CONCLUSIONS
Siblings of individuals with schizophrenia benefit from supportive verbal encoding conditions. Like individuals with schizophrenia, SIBs also show increased task-related activity in a larger number of PFC subregions than control subjects during deep verbal encoding.
Bonner-Jackson
Aaron
A
Washington University, Department of Psychology, St. Louis, Missouri 63130, USA. abonnerj@artsci.wustl.edu
Csernansky
John G
JG
Barch
Deanna M
DM
D000293:Adolescent; D000328:Adult; D001288:Attention; D001931:Brain Mapping; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D007600:Judgment; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall; D017397:Prefrontal Cortex / Q000503:physiopathology; D011930:Reaction Time / Q000235:genetics / Q000502:physiology; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D012565:Schizophrenic Psychology; D035781:Siblings; D014706:Verbal Learning