State-Specific Dynamic Functional Connectivity Patterns of Cognitive Intrusions in Schizophrenia: A Convergent Multi-Approach Resting-State fMRI Study

The neural basis of hallucinations and delusions remains unclear due to the heterogeneity of schizophrenia, leading to inconsistent findings across studies. This study addresses this gap by mapping edge-level connectivity to symptom severity to identify aberrant circuits. Using two symptom scores as proxies for cognitive intrusions, we highlighted a potential bridge between the two identified circuits. We decomposed the transient functional architecture of 83 medicated patients into two stable and low-dynamic states relative to a more dynamic or chaotic baseline brain state by integrating NeuroMark-constrained independent component analysis (CICA) with dynamic functional network connectivity (dFNC), followed by clustering performed on independent data partitions. To mitigate method-specific bias and assess feature robustness under strict generalization, we applied leave-one-feature-out (LOFO) ranking nested within a leave-one-out cross-validation (LOOCV) framework, evaluating feature contributions consistently across held-out subjects. Regularizing model complexity minimized misfit and identified reliable connectivity between the cognitive control (CC) and default mode network (DMN) as a robust neural predictor of symptom severity. Predictive strength was most pronounced for hallucinations (P3) in State 3 ($T = 2.73, P \approx 0.004$) and delusions (P1) in State 4 ($T = 2.06, P = 0.021$). The edge set in State 3 demonstrated a trend-level association with P3 scores under permutation testing (two-sided $P = 0.067$). At the edge level, insula–precuneus connectivity showed a significant association following FDR correction ($P = 0.036$), suggesting a localized contribution within a distributed pattern. No significant effects were observed for delusions. The observed trend may also illustrate how gate failure in the insula contributes to leakage, reinforcing the role of the precuneus in misattribution; the literature suggests that this process may lead to the emergence of hallucinatory behaviors, warranting further investigation.