Functional imaging of memory retrieval in deficit vs nondeficit schizophrenia.
BACKGROUND
Neuroimaging studies have provided evidence of abnormal frontal and temporal lobe function in schizophrenia. Frontal cortex abnormalities have been associated with negative symptoms and temporal lobe abnormalities with positive symptoms. The deficit and nondeficit forms of schizophrenia were predicted to differ in prefrontal cortical activity, but not in medial temporal lobe activity.


METHODS
Regional cerebral blood flow was studied using oxygen 15 positron emission tomography during 3 different memory retrieval conditions in 8 control subjects, 8 patients with the deficit syndrome, and 8 patients without the deficit syndrome. Behavioral and positron emission tomography data were analyzed using a mixed-effects model to test for population differences.


RESULTS
In all memory conditions, frontal cortex activity was higher in patients without the deficit syndrome than in patients with the deficit syndrome. During the attempt to retrieve poorly encoded words, patients without the deficit syndrome recruited the left frontal cortex to a significantly greater degree than did patients with the deficit syndrome. The 2 schizophrenia subtypes did not differ in the activity or recruitment of the hippocampus during memory retrieval.


CONCLUSIONS
Frontal cortex function during memory retrieval is differentially impaired in deficit and nondeficit schizophrenia, whereas hippocampal recruitment deficits are not significantly different between the 2 schizophrenia groups.
Heckers
S
S
Psychotic Disorders Unit, Psychiatric Neuroimaging Research Group, Massachusetts General Hospital, Boston, USA. heckers@psych.mgh.harvard.edu
Goff
D
D
Schacter
D L
DL
Savage
C R
CR
Fischman
A J
AJ
Alpert
N M
NM
Rauch
S L
SL
D000328:Adult; D003937:Diagnosis, Differential; D005625:Frontal Lobe / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008569:Memory Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology; D011939:Mental Recall / Q000502:physiology; D010104:Oxygen Radioisotopes; D017397:Prefrontal Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D012039:Regional Blood Flow; D012559:Schizophrenia / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D012565:Schizophrenic Psychology; D013702:Temporal Lobe / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D014055:Tomography, Emission-Computed
D010104:Oxygen Radioisotopes