Table 1.
Demographic parameters and reaction times.
Fig 1.
Group differences in reward anticipation.
Results for the contrast reward anticipation versus no outcome for healthy controls > schizophrenia patients (thresholded at p < 0.05, FDR-corrected for multiple comparisons, cluster level 30 voxels). Healthy controls displayed significant larger activations in the ventral striatum, hippocampus, caudate body and substantia nigra during reward-indicating versus neutral cues.
Table 2.
Activations for the contrast reward anticipation versus no outcome for healthy controls > schizophrenia patients.
Fig 2.
Brain areas that discriminated between schizophrenia patients and healthy control during reward anticipation using a multivariate classification approach.
Accuracy scores (percent correct classification) from SVM searchlight decoding were colour-coded to display the classification performance. Letters x, y, z denote the axial, coronal and sagittal planes, respectively. The maps are thresholded at a significance level of p<0.05, FDR-corrected (cluster level 30 voxels).
Table 3.
Multivariate classification of schizophrenia patients and healthy controls.
Fig 3.
Classification performance comparison.
The top and bottom panels depict percent correct classification rates (accuracies) obtained from the multivariate (linear SVM) and univariate (ROC) classification approach, respectively. The white line denotes the mask boundary of the ventral striatum. For illustrative reasons the accuracies where thresholded at 70% thus fewer significant voxels are displayed in the figure compared to the actually survived number of voxels after FDR correction.
Table 4.
Comparison of univariate and multivariate classification performance for the ventral striatum.
Fig 4.
Support vector regression (SVR) with PANSS negative scale for the schizophrenia group.
For the fMRI contrast monetary gain vs. no outcome there was a tight relationship between PANSS negative symptom scores and those predicted with SVR from activation patterns left ventral striatum within the clinical group. The right panel shows the correlation for the voxel (MNI: −12, 11, 1) within the left ventral striatum with the strongest relationship (R = 0.72) between actual and predicted PANSS negative scores. Each dot represents a schizophrenia patient.