Inefficient neural activity in patients with schizophrenia and nonpsychotic relatives of schizophrenic patients: evidence from a working memory task.
Studies of schizophrenia with functional MRI have shown hyper- and hypoactivations in various brain regions including the prefrontal cortex. Functional anomalies have also been reported in first-degree relatives of schizophrenic patients. The aim of this study was to examine working memory related brain functions in healthy subjects, schizophrenic patients and unaffected relatives and to determine the influence of psychopathology on these processes. A parametric n-back working memory task and functional MRI were used to examine 61 patients with schizophrenia, 11 nonpsychotic relatives of schizophrenic patients and a comparison group of 61 healthy subjects. The results indicated increased as well as decreased brain functions in schizophrenic patients compared to the control group depending on the task difficulty and the performance: during the attention task (0-back), which served as control condition, behavioral responses of patients and healthy subjects hardly differed but BOLD responses were considerably enhanced in schizophrenic patients. With increasing task difficulty differences between groups in BOLD responses diminished whereas behavioral deficits of patients increased. The examination of attention-independent working memory-functions (2- vs. 0-back) produced hypoactivations in patients, especially in frontal, temporal and subcortical brain regions. Furthermore, positive symptoms were associated with parietal dysfunctions. Behavioral performance and neural responses of unaffected relatives of schizophrenic patients were intermediate between schizophrenic patients and controls indicating slight brain dysfunctions. In addition, compensatory strategies were demonstrated. These findings suggest that the genetic risk for schizophrenia is accompanied by neural inefficiency which is associated with cognitive deficits, especially in difficult tasks.
Karch
Susanne
S
Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Nussbaumstrasse 7, D-80336 Munich, Germany. Susanne.Karch@med.uni-muenchen.de
Leicht
Gregor
G
Giegling
Ina
I
Lutz
Jürgen
J
Kunz
Jörg
J
Buselmeier
Moritz
M
Hey
Patric
P
Spörl
Alexander
A
Jäger
Lorenz
L
Meindl
Thomas
T
Pogarell
Oliver
O
Möller
Hans-Jürgen
HJ
Hegerl
Ulrich
U
Rujescu
Dan
D
Mulert
Christoph
C
D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D001931:Brain Mapping; D005190:Family; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology; D012565:Schizophrenic Psychology
D010100:Oxygen