Optimising visual solutions for complex strategic scenarios : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University, Wellington, New Zealand

Attempts to pre-emptively improve post-disaster outcomes need to reflect an improved understanding of cognitive adaptations made by collaborating researchers and practitioners. This research explored the use of visual logic models to enhance the quality of decisions being made by these professionals. The research looked at the way visual representations serve to enhance these decisions, as part of cognitive adaptations to considering the complexity of relevant pre-disaster conditions constituting community resilience. It was proposed that a visual logic model display, using boxes and arrows to display linkages between activities and downstream objectives, could support effective, efficient and responsive approaches to relevant community resilience interventions being carried out in a pre-disaster context. The first of three phases comprising this thesis used Q-methodology to identify patterns of opinions concerning building a shared framework of pre-disaster, community resilience indicators for this purpose. Three patterns identified helped to assess the needs for applied research undertaken in phase two. The second phase of this thesis entailed building an action-focused logic model to enhance associated collaborations between emergency management practitioners and researchers. An analysis of participant interviews determined that the process used to build this logic model served as a catalyst for research which could help improve community resilience interventions. The third phase used an experimental approach to different display formats produced during phase two to test whether a visual logic model display stimulated a higher quality of decisions, compared with a more conventional, text-based chart of key performance indicators. Results supported the use of similar methods for much larger scale research to assess how information displays support emergency management decisions with wide-ranging, longer-term implications. Overall, results from these three phases indicate that certain logic model formats can help foster collaborative efforts to improve characteristics of community resilience against disasters. This appears to occur when a logic model forms an integrated component of efficient cognitive dynamics across a network of decision making agents. This understanding of logic model function highlights clear opportunities for further research. It also represents a novel contribution to knowledge about using logic models to support emergency management decisions with complex, long term implications

Examining the association between posttraumatic stress disorder and disruptions in cortical networks identified using data-driven methods

Posttraumatic stress disorder (PTSD) is associated with lower cortical thickness (CT) in prefrontal, cingulate, and insular cortices in diverse trauma-affected samples. However, some studies have failed to detect differences between PTSD patients and healthy controls or reported that PTSD is associated with greater CT. Using data-driven dimensionality reduction, we sought to conduct a well-powered study to identify vulnerable networks without regard to neuroanatomic boundaries. Moreover, this approach enabled us to avoid the excessive burden of multiple comparison correction that plagues vertex-wise methods. We derived structural covariance networks (SCNs) by applying non-negative matrix factorization (NMF) to CT data from 961 PTSD patients and 1124 trauma-exposed controls without PTSD. We used regression analyses to investigate associations between CT within SCNs and PTSD diagnosis (with and without accounting for the potential confounding effect of trauma type) and symptom severity in the full sample. We performed additional regression analyses in subsets of the data to examine associations between SCNs and comorbid depression, childhood trauma severity, and alcohol abuse. NMF identified 20 unbiased SCNs, which aligned closely with functionally defined brain networks. PTSD diagnosis was most strongly associated with diminished CT in SCNs that encompassed the bilateral superior frontal cortex, motor cortex, insular cortex, orbitofrontal cortex, medial occipital cortex, anterior cingulate cortex, and posterior cingulate cortex. CT in these networks was significantly negatively correlated with PTSD symptom severity. Collectively, these findings suggest that PTSD diagnosis is associated with widespread reductions in CT, particularly within prefrontal regulatory regions and broader emotion and sensory processing cortical regions

Neuroimaging-based classification of PTSD using data-driven computational approaches: A multisite big data study from the ENIGMA-PGC PTSD consortium

Background: Recent advances in data-driven computational approaches have been helpful in devising tools to objectively diagnose psychiatric disorders. However, current machine learning studies limited to small homogeneous samples, different methodologies, and different imaging collection protocols, limit the ability to directly compare and generalize their results. Here we aimed to classify individuals with PTSD versus controls and assess the generalizability using a large heterogeneous brain datasets from the ENIGMA-PGC PTSD Working group. Methods: We analyzed brain MRI data from 3,477 structural-MRI; 2,495 resting state-fMRI; and 1,952 diffusion-MRI. First, we identified the brain features that best distinguish individuals with PTSD from controls using traditional machine learning methods. Second, we assessed the utility of the denoising variational autoencoder (DVAE) and evaluated its classification performance. Third, we assessed the generalizability and reproducibility of both models using leave-one-site-out cross-validation procedure for each modality. Results: We found lower performance in classifying PTSD vs. controls with data from over 20 sites (60 % test AUC for s-MRI, 59 % for rs-fMRI and 56 % for d-MRI), as compared to other studies run on single-site data. The performance increased when classifying PTSD from HC without trauma history in each modality (75 % AUC). The classification performance remained intact when applying the DVAE framework, which reduced the number of features. Finally, we found that the DVAE framework achieved better generalization to unseen datasets compared with the traditional machine learning frameworks, albeit performance was slightly above chance. Conclusion: These results have the potential to provide a baseline classification performance for PTSD when using large scale neuroimaging datasets. Our findings show that the control group used can heavily affect classification performance. The DVAE framework provided better generalizability for the multi-site data. This may be more significant in clinical practice since the neuroimaging-based diagnostic DVAE classification models are much less site-specific, rendering them more generalizable