Medicine and Health Sciences Commons^™

Classifying Heterogeneous Presentations Of Ptsd Via The Default Mode, Central Executive, And Salience Networks With Machine Learning., Andrew A Nicholson, Sherain Harricharan, Maria Densmore, Richard W J Neufeld, Tomas Ros, Margaret C Mckinnon, Paul A Frewen, Jean Theberge, Rakesh Jetly, David Pedlar, Ruth A Lanius

Department of Medicine Publications

Intrinsic connectivity networks (ICNs), including the default mode network (DMN), the central executive network (CEN), and the salience network (SN) have been shown to be aberrant in patients with posttraumatic stress disorder (PTSD). The purpose of the current study was to a) compare ICN functional connectivity between PTSD, dissociative subtype PTSD (PTSD+DS) and healthy individuals; and b) to examine the use of multivariate machine learning algorithms in classifying PTSD, PTSD+DS, and healthy individuals based on ICN functional activation. Our neuroimaging dataset consisted of resting-state fMRI scans from 186 participants [PTSD (n = 81); PTSD + DS (n = 49); and …

Complexity In Mood Disorder Diagnosis: Fmri Connectivity Networks Predicted Medication-Class Of Response In Complex Patients, E Osuch, S Gao, M Wammes, Jean Theberge, P Willimason, R J Neufeld, Y Du, J Sui, V Calhoun

Department of Medicine Publications

OBJECTIVE: This study determined the clinical utility of an fMRI classification algorithm predicting medication-class of response in patients with challenging mood diagnoses.

METHODS: Ninety-nine 16-27-year-olds underwent resting state fMRI scans in three groups-BD, MDD and healthy controls. A predictive algorithm was trained and cross-validated on the known-diagnosis patients using maximally spatially independent components (ICs), constructing a similarity matrix among subjects, partitioning the matrix in kernel space and optimizing support vector machine classifiers and IC combinations. This classifier was also applied to each of 12 new individual patients with unclear mood disorder diagnoses.

RESULTS: Classification within the known-diagnosis group was approximately …

Desynchronization Of Autonomic Response And Central Autonomic Network Connectivity In Posttraumatic Stress Disorder, Janine Thome, Maria Densmore, Paul A Frewen, Margaret C Mckinnon, Jean Théberge, Andrew A Nicholson, Julian Koenig, Julian F Thayer, Ruth A Lanius

Department of Medicine Publications

OBJECTIVES: Although dysfunctional emotion regulatory capacities are increasingly recognized as contributing to posttraumatic stress disorder (PTSD), little work has sought to identify biological markers of this vulnerability. Heart rate variability (HRV) is a promising biomarker that, together with neuroimaging, may assist in gaining a deeper understanding of emotion dysregulation in PTSD. The objective of the present study was, therefore, to characterize autonomic response patterns, and their related neuronal patterns in individuals with PTSD at rest.

METHODS: PTSD patients (N = 57) and healthy controls (N = 41) underwent resting-state fMRI. Connectivity patterns of key regions within the central autonomic network …

Aberrant Functional Connectivity Of The Amygdala Complexes In Ptsd During Conscious And Subconscious Processing Of Trauma-Related Stimuli, Daniela Rabellino, Maria Densmore, Paul A Frewen, Jean Theberge, Margaret C Mckinnon, Ruth A Lanius

Department of Medicine Publications

Post-traumatic stress disorder (PTSD) is characterized by altered functional connectivity of the amygdala complexes at rest. However, amygdala complex connectivity during conscious and subconscious threat processing remains to be elucidated. Here, we investigate specific connectivity of the centromedial amygdala (CMA) and basolateral amygdala (BLA) during conscious and subconscious processing of trauma-related words among individuals with PTSD (n = 26) as compared to non-trauma-exposed controls (n = 20). Psycho-physiological interaction analyses were performed using the right and left amygdala complexes as regions of interest during conscious and subconscious trauma word processing. These analyses revealed a differential, context-dependent responses by each amygdala …

Resting State Default-Mode Network Connectivity In Early Depression Using A Seed Region-Of-Interest Analysis: Decreased Connectivity With Caudate Nucleus., Robyn Bluhm, Peter Williamson, Ruth Lanius, Jean Theberge, Maria Densmore, Robert Bartha, Richard Neufeld, Elizabeth Osuch

Department of Medicine Publications

AIM: Reports on resting brain activity in healthy controls have described a default-mode network (DMN) and important differences in DMN connectivity have emerged for several psychiatric conditions. No study to date, however, has investigated resting-state DMN in relatively early depression before years of medication treatment. The objective of the present study was, therefore, to investigate the DMN in patients seeking help from specialized mental health services for the first time for symptoms of depression.

METHODS: Fourteen depressed subjects and 15 matched controls were scanned using 4-T functional magnetic resonance imaging while resting with eyes closed. All but one subject was …

Spontaneous Low-Frequency Fluctuations In The Bold Signal In Schizophrenic Patients: Anomalies In The Default Network, Robyn L Bluhm, Jodi Miller, Ruth A Lanius, Elizabeth A Osuch, Kristine Boksman, R W J Neufeld, Jean Theberge, Betsy Schaefer, Peter Williamson

Department of Medicine Publications

Spontaneous low-frequency fluctuations in the blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (MRI) signal have been shown to reflect neural synchrony between brain regions. A "default network" of spontaneous low-frequency fluctuations has been described in healthy volunteers during stimulus-independent thought. Negatively correlated with this network are regions activated during attention-demanding tasks. Both these networks involve brain regions and functions that have been linked with schizophrenia in previous research. The present study examined spontaneous slow fluctuations in the BOLD signal at rest, as measured by correlation with low-frequency oscillations in the posterior cingulate, in 17 schizophrenic patients, and 17 comparable …