Research Interests:
Research Interests:
Research Interests:
Research Interests:
The primary aim of this commentary is to describe trauma-related dissociation and altered states of consciousness in the context of a four-dimensional model that has recently been proposed (Frewen & Lanius, 2015). This model categorizes... more
The primary aim of this commentary is to describe trauma-related dissociation and altered states of consciousness in the context of a four-dimensional model that has recently been proposed (Frewen & Lanius, 2015). This model categorizes symptoms of trauma-related psychopathology into (1) those that occur within normal waking consciousness and (2) those that are dissociative and are associated with trauma-related altered states of consciousness (TRASC) along four dimensions: (1) time; (2) thought; (3) body; and (4) emotion. Clinical applications and future research directions relevant to each dimension are discussed. Conceptualizing TRASC across the dimensions of time, thought, body, and emotion has transdiagnostic implications for trauma-related disorders described in both the Diagnostic Statistical Manual and the International Classifications of Diseases. The four-dimensional model provides a framework, guided by existing models of dissociation, for future research examining the ph...
Research Interests:
The cerebellum plays a key role not only in motor function but also in affect and cognition. Although several psychopathological disorders have been associated with overall cerebellar dysfunction, it remains unclear whether different... more
The cerebellum plays a key role not only in motor function but also in affect and cognition. Although several psychopathological disorders have been associated with overall cerebellar dysfunction, it remains unclear whether different regions of the cerebellum contribute uniquely to psychopathology. Accordingly, we compared seed-based resting-state functional connectivity of the anterior cerebellum (lobule IV-V), of the posterior cerebellum (Crus I), and of the anterior vermis across posttraumatic stress disorder (PTSD; n = 65), its dissociative subtype (PTSD + DS; n = 37), and non-trauma-exposed healthy controls (HC; n = 47). Here, we observed decreased functional connectivity of the anterior cerebellum and anterior vermis with brain regions involved in somatosensory processing, multisensory integration, and bodily self-consciousness (temporo-parietal junction, postcentral gyrus, and superior parietal lobule) in PTSD + DS as compared to PTSD and HC. Moreover, the PTSD + DS group sho...
Research Interests:
Key evidence points toward alterations in the neurocircuitry of large-scale networks among patients with posttraumatic stress disorder (PTSD). The pulvinar is a thalamic region displaying reciprocal connectivity with the cortex and has... more
Key evidence points toward alterations in the neurocircuitry of large-scale networks among patients with posttraumatic stress disorder (PTSD). The pulvinar is a thalamic region displaying reciprocal connectivity with the cortex and has been shown to modulate alpha synchrony to facilitate network communication. During rest, the pulvinar displays functional connectivity with the posterior parietal cortex (PPC), a heteromodal network of brain areas underlying multisensory integration and socioaffective functions that are shown at deficit in PTSD. Accordingly, this study seeks to reveal the resting-state functional connectivity (rsFC) patterns of individuals with PTSD, its dissociative subtype (PTSD + DS) and healthy controls. A whole-brain rsFC analysis was conducted using SPM12 and PickAtlas. Connectivity was analyzed for the left and right pulvinar across groups of individuals with PTSD (n = 81), PTSD + DS (n = 49), and controls (n = 51). As compared to PTSD, controls displayed signi...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
To investigate the functional connectivity of large-scale intrinsic connectivity networks (ICNs) in post-traumatic stress disorder (PTSD) during subliminal and supraliminal presentation of threat-related stimuli. Group independent... more
To investigate the functional connectivity of large-scale intrinsic connectivity networks (ICNs) in post-traumatic stress disorder (PTSD) during subliminal and supraliminal presentation of threat-related stimuli. Group independent component analysis was utilized to study functional connectivity within the ICNs most correlated with the Default-mode Network (DMN), Salience Network (SN), and Central Executive Network (CEN) in PTSD participants (n = 26) as compared to healthy controls (n = 20) during sub- and supraliminal processing of threat-related stimuli. Comparing patients with PTSD with healthy participants, prefrontal and anterior cingulate cortex involved in top-down regulation showed increased integration during subliminal threat processing within the CEN and SN and during supraliminal threat processing within the DMN. The right amygdala showed increased connectivity with the DMN during subliminal processing in PTSD as compared to controls. Brain regions associated with self-aw...
Research Interests:
Research Interests:
The newly proposed criteria for posttraumatic stress disorder (PTSD) in the Diagnostic and Statistical Manual (DSM-V) include dysregulation of a variety of emotional states including fear, anger, guilt, and shame, in addition to... more
The newly proposed criteria for posttraumatic stress disorder (PTSD) in the Diagnostic and Statistical Manual (DSM-V) include dysregulation of a variety of emotional states including fear, anger, guilt, and shame, in addition to dissociation and numbing. Consistent with these revisions, we postulate two models of emotion dysregulation in PTSD in which fear is not the prevailing emotion but is only one of several components implicated in a dysregulated emotional system that also mediates problems regulating anger, guilt, shame, dissociation, and numbing.We discuss whether there is a relationship between fear and other emotion regulation systems that may help further our understanding of PTSD and its underlying neurocircuitry. Two pathways describing the relationship between fear and other emotion regulation systems in PTSD are proposed. The first pathway describes emotion dysregulation as an outcome of fear conditioning through stress sensitization and kindling. The second pathway vi...
Research Interests:
Symptoms of anhedonia, or deficits in the ability to experience positive affect, are increasingly recognized as an outcome of traumatic stress. Herein we demonstrate a phenomenon of "negative affective interference",... more
Symptoms of anhedonia, or deficits in the ability to experience positive affect, are increasingly recognized as an outcome of traumatic stress. Herein we demonstrate a phenomenon of "negative affective interference", specifically, negative affective responses to positive events, in association with childhood trauma history. Young adults (n=99) completed a Hedonic Deficit & Interference Scale (HDIS), a self-report measure developed for this study, as well as a modified version of the Fawcette-Clarke Pleasure Capacity Scale that assessed not only positive but also negative affective responses to positive events. The two assessment approaches demonstrated convergent validity and predicted concurrent individual differences in trait positive and negative affect, and extraversion and neuroticism. Histories of childhood emotional and sexual abuse were differentially associated with negative affective responses to positive events. Future research and clinical directions are discus...
Research Interests:
Research Interests: Psychology, Cognitive Science, Neuroimaging, Magnetic Resonance Imaging, Adolescent, and 15 moreMedicine, Prefrontal Cortex, Emotions, Humans, Cerebral Cortex, Female, Amygdala, Middle Aged, Precuneus, Posterior Cingulate, Adult, Parietal Lobe, Sex Factors, Functional Neuroimaging, and Neurosciences
Research Interests:
Research Interests: Psychology, Anterior Cingulate, Magnetic Resonance Imaging, Emotion Regulation, Imagination, and 15 moreMedicine, Emotions, Neural correlates of consciousness, Dissociation, Brain, Humans, Posttraumatic stress disorder, Insula, Functional Magnetic Resonance Imaging, Female, Male, Magnetic Resonance, Middle Aged, Adult, and Anterior cingulate cortex
Research Interests:
Research Interests: Cognitive Science, Pain, Magnetic Resonance Imaging, Borderline Personality Disorder, Medicine, and 15 moreComorbidity, Humans, Functional Magnetic Resonance Imaging, Female, Pain Perception, Dissociative disorders, Clinical Sciences, Adult, Inferior frontal gyrus, Limbic System, Parahippocampal Gyrus, Neurosciences, Frontal Lobe, Pain Threshold, and Neuropsychological Tests
Research Interests:
Research Interests: Anterior Cingulate, Magnetic Resonance Imaging, Emotion Regulation, Medicine, Emotions, and 15 moreBiological Sciences, Biological Psychiatry, Brain Mapping, Brain, Humans, Cerebral Cortex, Posttraumatic stress disorder, Functional Magnetic Resonance Imaging, Female, Male, Biological, Arousal, Adult, Anterior cingulate cortex, and Medical and Health Sciences
Research Interests: Anterior Cingulate, Imagination, Biological Sciences, Biological Psychiatry, Dissociation, and 15 moreBrain Mapping, Brain, Humans, Child, Child Abuse, Functional Magnetic Resonance Imaging, Female, Functional Imaging, Biological, Heart rate, Dissociative disorders, Arousal, Adult, Inferior frontal gyrus, and Limbic Lobe
Research Interests: Psychology, Magnetic Resonance Imaging, Borderline Personality Disorder, Medicine, Prefrontal Cortex, and 13 moreHumans, Cerebral Cortex, Default Mode Network, Functional Magnetic Resonance Imaging, Female, Pain Perception, Posterior Cingulate, Adult, Archives General Psychiatry, Anterior cingulate cortex, Case Control Studies, Psychology and Cognitive Sciences, and Medical and Health Sciences
Research Interests:
Research Interests: Neuroscience, Psychology, Magnetic Resonance Imaging, Imagination, Medicine, and 9 moreFunctional Connectivity, Brain, Humans, Functional Magnetic Resonance Imaging, American Journal of Psychiatry, American, Severity of Illness Index, Psychology and Cognitive Sciences, and Medical and Health Sciences
Research Interests: Psychology, Magnetic Resonance Imaging, Stress, Medicine, Affect, and 11 moreHumans, Cerebral Cortex, Chronic Disease, American Journal of Psychiatry, American, Dissociative disorders, Amygdala, Memory Disorders, American J of Psychiatry, Psychology and Cognitive Sciences, and Medical and Health Sciences
Research Interests:
Research Interests:
Research Interests:
Research Interests:
This checklist is intended to encourage robust experimental design and clear reporting for clinical and cognitive-behavioural neurofeedback experiments.
The innate alarm system (IAS) models the neurocircuitry involved in threat processing in posttraumatic stress disorder (PTSD). Here, we investigate a primary subcortical structure of the IAS model, the superior colliculus (SC), where the... more
The innate alarm system (IAS) models the neurocircuitry involved in threat processing in posttraumatic stress disorder (PTSD). Here, we investigate a primary subcortical structure of the IAS model, the superior colliculus (SC), where the SC is thought to contribute to the mechanisms underlying threat-detection in PTSD. Critically, the functional connectivity between the SC and other nodes of the IAS remains unexplored. We conducted a resting-state fMRI study to investigate the functional architecture of the IAS, focusing on connectivity of the SC in PTSD (n = 67), its dissociative subtype (n = 41), and healthy controls (n = 50) using region-of-interest seed-based analysis. We observed group-specific resting state functional connectivity between the SC for both PTSD and its dissociative subtype, indicative of dedicated IAS collicular pathways in each group of patients. When comparing PTSD to its dissociative subtype, we observed increased resting state functional connectivity between...
Research Interests: Psychology, Cognitive Science, Posttraumatic Stress Disorder (PTSD), Magnetic Resonance Imaging, Medicine, and 15 moreDissociation, Brain Mapping, Humans, Female, Male, Dissociative disorders, Superior Colliculus, Rest, Adult, Analysis of Variance, Human Brain Mapping, Neural pathways, resting state fMRI, Neurosciences, and Psychiatric Status Rating Scales
The field of psychiatry would benefit significantly from developing objective biomarkers that could facilitate the early identification of heterogeneous subtypes of illness. Critically, although machine learning pattern recognition... more
The field of psychiatry would benefit significantly from developing objective biomarkers that could facilitate the early identification of heterogeneous subtypes of illness. Critically, although machine learning pattern recognition methods have been applied recently to predict many psychiatric disorders, these techniques have not been utilized to predict subtypes of posttraumatic stress disorder (PTSD), including the dissociative subtype of PTSD (PTSD + DS). Using Multiclass Gaussian Process Classification within PRoNTo, we examined the classification accuracy of: (i) the mean amplitude of low-frequency fluctuations (mALFF; reflecting spontaneous neural activity during rest); and (ii) seed-based amygdala complex functional connectivity within 181 participants [PTSD (n = 81); PTSD + DS (n = 49); and age-matched healthy trauma-unexposed controls (n = 51)]. We also computed mass-univariate analyses in order to observe regional group differences [false-discovery-rate (FDR)-cluster corre...
Research Interests:
Research Interests: Psychology and Medicine
Research Interests:
Research Interests: Psychology, Cognitive Science, Magnetic Resonance Imaging, Vestibular System, Dissociation, and 15 moreHumans, Cerebral Cortex, Female, Male, Dissociative disorders, Middle Aged, Rest, Oxygen, Adult, Analysis of Variance, Neuropsychologia, Neural pathways, resting state fMRI, Neurosciences, and Case Control Studies
Research Interests:
Posttraumatic stress disorder (PTSD) is associated with decreased top-down emotion modulation from medial prefrontal cortex (mPFC) regions, a pathophysiology accompanied by hyperarousal and hyperactivation of the amygdala. By contrast,... more
Posttraumatic stress disorder (PTSD) is associated with decreased top-down emotion modulation from medial prefrontal cortex (mPFC) regions, a pathophysiology accompanied by hyperarousal and hyperactivation of the amygdala. By contrast, PTSD patients with the dissociative subtype (PTSD + DS) often exhibit increased mPFC top-down modulation and decreased amygdala activation associated with emotional detachment and hypoarousal. Crucially, PTSD and PTSD + DS display distinct functional connectivity within the PFC, amygdala complexes, and the periaqueductal gray (PAG), a region related to defensive responses/emotional coping. However, differences in directed connectivity between these regions have not been established in PTSD, PTSD + DS, or controls. To examine directed (effective) connectivity among these nodes, as well as group differences, we conducted resting-state stochastic dynamic causal modeling (sDCM) pairwise analyses of coupling between the ventromedial (vm)PFC, the bilateral ...
Research Interests: Psychology, Cognitive Science, Fear, Magnetic Resonance Imaging, Emotion Regulation, and 15 moreMedicine, Multivariate Analysis, Dissociation, Brain Mapping, Brain, Humans, Female, Male, Dissociative disorders, Dynamic Causal Modelling, Adult, Human Brain Mapping, Neural pathways, Bayes Theorem, and Neurosciences
The present study investigated resting fMRI connectivity within the default mode (DMN), salience (SN), and central executive (CEN) networks in relation to neurocognitive performance and symptom severity in trauma-exposed patients with... more
The present study investigated resting fMRI connectivity within the default mode (DMN), salience (SN), and central executive (CEN) networks in relation to neurocognitive performance and symptom severity in trauma-exposed patients with major depressive disorder (MDD). Group independent component analysis was conducted among patients with MDD (n = 21), examining DMN, SN, and CEN connectivity in relation to neurocognitive performance and symptom severity. Activation in these networks was also compared between the patient group and healthy controls (n = 20). Among the patient group, higher levels of performance on measures of verbal memory and executive functioning were related to increased connectivity within the DMN (i.e., inferior parietal lobe; precuneus). Greater depression severity was related to reduced connectivity between the SN and a node of the DMN (i.e., posterior cingulate cortex) and higher depersonalization symptoms were related to enhanced connectivity between the SN and...
Research Interests:
Dissociative experiences, involving altered states of consciousness, have long been understood as a consequence or response to traumatic experiences, where a reduced level of consciousness may aid in survival during and after a traumatic... more
Dissociative experiences, involving altered states of consciousness, have long been understood as a consequence or response to traumatic experiences, where a reduced level of consciousness may aid in survival during and after a traumatic event. Indeed, the dissociative subtype of post-traumatic stress disorder (PTSD-DS) was added recently to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5). Dissociative symptoms are present across a host of neuropsychiatric conditions, including PTSD, psychotic spectrum illnesses, anxiety and mood disorders. Transdiagnostically, the presence of dissociative symptoms is associated with a greater illness burden and reduced treatment outcomes. Critically, dissociative symptoms are related to impaired performance on measures of attention, executive functioning, memory, and social cognition and may contribute to the widespread cognitive dysfunction observed across psychiatric illnesses. Despite this knowledge, the relation b...
Research Interests:
Research Interests: Neuroscience, Psychology, Cognitive Science, Magnetic Resonance Imaging, Medicine, and 15 moreAutonomic Nervous System, Heart rate variability, Brain, Humans, Female, Male, Heart rate, Young Adult, Middle Aged, Rest, Adult, Retrospective Studies, Human Brain Mapping, Neural pathways, and Neurosciences
Amygdala dysregulation has been shown to be central to the pathophysiology of posttraumatic stress disorder (PTSD) representing a critical treatment target. Here, amygdala downregulation was targeted using real-time fMRI neurofeedback... more
Amygdala dysregulation has been shown to be central to the pathophysiology of posttraumatic stress disorder (PTSD) representing a critical treatment target. Here, amygdala downregulation was targeted using real-time fMRI neurofeedback (rt-fMRI-nf) in patients with PTSD, allowing us to examine further the regulation of emotional states during symptom provocation. Patients (n = 10) completed three sessions of rt-fMRI-nf with the instruction to downregulate activation in the amygdala, while viewing personalized trauma words. Amygdala downregulation was assessed by contrasting (a) regulate trials, with (b) viewing trauma words and not attempting to regulate. Training was followed by one transfer run not involving neurofeedback. Generalized psychophysiological interaction (gPPI) and dynamic causal modeling (DCM) analyses were also computed to explore task-based functional connectivity and causal structure, respectively. It was found that PTSD patients were able to successfully downregula...