Visualizing fronto‐striatal circuitry and neuroleptic effects in schizophrenia

Abstract

Disturbances in fronto‐striatal circuitry have been postulated to be important in schizophrenia. Positron emission tomography typically shows decreased metabolic rates in these areas relative to other brain areas in schizophrenia. After treatment with typical neuroleptics, striatal metabolic rates are increased, but other brain areas tend not to show significant changes. Atypical neuroleptics less markedly affect striatal metabolic rates, but show wider cortical effects. In order to examine fronto‐striatal circuitry, a technique for visualizing the correlations between metabolic rates in all brain areas was applied in 33 controls and 27 unmedicated schizophrenic patients. Correlation images revealed strong fronto‐striatal connections in controls, but weak fronto‐striatal links in schizophrenic patients. Changes in striatal circuits, also reflected in recent anatomical studies, may be important for understanding antipsychotic effects.

Abnormal Glucose Metabolism in the Mediodorsal Nucleus of the Thalamus in Schizophrenia

“…FDG PET studies have confirmed lower metabolic rates in all three areas (57), and studies of N-acetyl-D-aspartic acid concentrations have demonstrated lower metabolic rates in frontal and striatal areas (58). Since the centromedian nucleus sends an excitatory projection to the striatum (18), diminished centromedian nucleus activity would be consistent with the lower levels of striatal and cortical activation seen in patients with schizophrenia, compared to healthy subjects.…”

Anomalous Prefrontal-Subcortical Activation in Familial Pediatric BipolarDisorder

“…Stimulants, however, were withheld for 24 to 48 hours before fMRI to minimize their behavioral and cerebral effects. There have been reports of increased caudate activity 83 and decreased ACC activity 84 associated with antipsychotic medications as well as decreased ventral ACC activity associated with antidepressants. 81,85 Although betweengroup caudate differences may have been related to this phenomenon, it is unlikely to explain the findings of increased ACC activity in subjects with BD.…”

Interregional cerebral metabolic associativity during a continuous performance task (Part I): Healthy adults

“…that may dominate interregional covariances, and which should be a concern with any examination of this kind. In this regard, several studies have examined interregional covariance in major depression (Mallet et al, 1998; Anand et al, 2005), schizophrenia (Clark et al, 1984; Katz et al, 1996; Friston et al, 1996; Buchsbaum et al, 1999; Mallet et al, 1998; Andreason, 1999; Meyer-Lindenberg et al, 2001), obsessive-compulsive disorder (Horwitz et al, 1991b; Mallet et al, 1998), and Down’s syndrome (Horwitz et al, 1990). …”