F102. EARLY STAGES OF CONCEPTUAL DISORGANISATION AND REDISTRIBUTION OF CORTICAL HUBS IN UNTREATED FIRST EPISODE PSYCHOSIS; A 7T FMRI STUDY
Bibliographic record
Abstract
Of the various symptom complexes of established psychosis, network level dysconnectivity has been widely studied in association with positive and negative symptoms. Very few studies have focused on studying the dysconnectivity patterns associated with disorganization, specifically conceptual disorganization (CD), which explains the impairments in both the goal-directed sequencing of thought processes and real-world functioning. Systematic reviews have revealed aberrant connectivity patterns in formal thought disorder (a construct related to CD) at all stages of the illness, suggesting the underlying persistence of CD. However, these studies investigate connectivity patterns between specific regions of interest or resting state networks. No studies have investigated the whole-brain functional correlates of CD in psychosis. We thus sought to investigate the brain regions explaining the severity of CD in patients with first-episode psychosis (FEPs) in comparison with healthy controls (HCs). Participants were recruited as part of a longitudinal neuroimaging project that follows changes in early psychosis during the course of treatment. 31 HC and 38 antipsychotic-naive FEP subjects were included in the study sample. Subjects were assessed using DSM-5 criteria and the 8 item Positive and Negative Syndrome Scale (PANSS-8) and underwent 2 magnetic resonance imaging (MRI) scans at 7T (one T2*-weighted resting-state functional MRI (rs-fMRI) scan, one T1-weighted structural MRI). After preprocessing, whole-brain binarized degree centrality (bDC) maps were computed to characterize the patterns of network connectivity in the two study samples. Statistical analyses included the following: 1) A two-sample t-test comparing connectivity patterns in the HC and FEP groups with bDC maps as the dependent variable, examining the effect of diagnosis accounting for gender as the covariate, 2) Similarly, a two-sample t-test comparing connectivity patterns in the two patient groups (low CD or Low P2, high CD or High P2) with bDC maps as the dependent variable, examining the effect of the severity of symptoms accounting for gender as the covariate. Compared to HCs, the FEPs showed a reduction in hubness of a cluster located in the superior temporal gyrus (rSTG) (right: t = 5.00, p < 0.001). This cluster was functionally connected with clusters in the middle frontal gyrus (left: t = 8.41, p < 0.001; right: t = 7.59, p < 0.001), cerebellum (left: t = 8.02, p < 0.001) and thalamus (left: t = 9.72, p < 0.001). In patients exhibiting high CD severity, increased hubness of a medial superior parietal (mSPL) cluster (left: t = 4.93, p = 0.001) was observed, compared to patients exhibiting low CD severity. This cluster was functionally connected with clusters in the superior temporal (right: t = 8.39, p < 0.001) and middle temporal (right: t = 7.07, p < 0.001) gyri. The summary measure (first eigenvariate) of the mSPL cluster’s centrality showed strong correlation with the severity of CD but no other symptoms. Our observations extend the previous findings of reduced hubness in the superior temporal and insular regions in established schizophrenia to early-stage untreated, active phase of illness. Nevertheless, the increase in peripheral hubness in this first-episode sample was limited to conceptually disorganized patients, indicating the possible role of functional cortical reorganization and re-routing of information transfer in early stages of thought disorder.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".