Robyn Bluhm

Resting state default-mode network connectivity in early depression using a seed region-of-interest analysis : Decreased connectivity with caudate nucleus

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.

Default mode network connectivity as a predictor of post-traumatic stress disorder symptom severity in acutely traumatized subjects

Objective:  The goal of this study was to investigate the relationship between default mode network connectivity and the severity of post‐traumatic stress disorder (PTSD) symptoms in a sample of eleven acutely traumatized subjects.

Default mode network connectivity : effects of age, sex, and analytic approach

The ‘default mode network’ is a set of brain regions showing correlated, low-frequency activity during rest. It includes the posterior cingulate/precuneus, medial prefrontal cortex, and bilateral inferior parietal cortex. Earlier studies have characterized this network using either region of interest-based correlation analyses or data-driven techniques; however, there is some disagreement over which method is superior. We conducted both types of analysis on a large (N=40) data set and also investigated age and sex differences in the network. Both region of interest-based analyses and independent component analysis identified the default mode network. Age and sex differences were small and there was less agreement between analytic techniques regarding age and sex effects than regarding default mode network structure.

How understanding the neurobiology of complex post-traumatic stress disorder can inform clinical practice: A social cognitive and affective neuroscience approach

Lanius RA, Bluhm RL, Frewen PA. How understanding the neurobiology of complex post‐traumatic stress disorder can inform clinical practice: a social cognitive and affective neuroscience approach.

Default network connectivity during a working memory task.

The default network exhibits correlated activity at rest and has shown decreased activation during performance of cognitive tasks. There has been little investigation of changes in connectivity of this network during task performance. In this study, we examined task‐related modulation of connectivity between two seed regions from the default network posterior cingulated cortex (PCC) and medial prefrontal cortex (mPFC) and the rest of the brain in 12 healthy adults. The purpose was to determine (1) whether connectivity within the default network differs between a resting state and performance of a cognitive (working memory) task and (2) whether connectivity differs between these nodes of the default network and other brain regions, particularly those implicated in cognitive tasks. There was little change in connectivity with the other main areas of the default network for either seed region, but moderate task‐related changes in connectivity occurred between seed regions and regions outside the default network. For example, connectivity of the mPFC with the right insula and the right superior frontal gyrus decreased during task performance. Increased connectivity during the working memory task occurred between the PCC and bilateral inferior frontal gyri, and between the mPFC and the left inferior frontal gyrus, cuneus, superior parietal lobule, middle temporal gyrus and cerebellum. Overall, the areas showing greater correlation with the default network seed regions during task than at rest have been previously implicated in working memory tasks. These changes may reflect a decrease in the negative correlations occurring between the default and task‐positive networks at rest. Hum Brain Mapp, 2011.

Brain activation to favorite music in healthy controls and depressed patients.

Reward-processing neurocircuitry has been delineated using verbal or visual processing and/or decision-making tasks. We examined more basic processes of listening to enjoyable music in healthy and depressed patients. The paradigm was passive, individualized, and brief. Sixteen depressed and 15 control individuals provided favorite music and identified neutral music from selections provided. In the fMRI scanner, individuals heard their neutral and their favorite music for 3 min each. Favorite versus neutral music-listening contrasts showed greater activation in controls than depressed patients in medial orbital frontal cortex and nucleus accumbens/ventral striatum. Left medial prefrontal cortex activity was positively correlated with pleasure scores, whereas middle temporal cortex and globus pallidus were negatively correlated with pleasure. This paradigm activated neurocircuitry of reward processing and showed clinically meaningful alterations in depression.

Neurophysiological Responses to Traumatic Reminders in the Acute Aftermath of Serious Motor Vehicle Collisions Using [15O]-H2O Positron Emission Tomography

BACKGROUND Neuroimaging studies report that individuals with posttraumatic stress disorder show abnormal responses in the amygdala and medial prefrontal cortex (mPFC)/anterior cingulate cortex (ACC) during exposure to traumatic reminders. However, neural responses arising in the early aftermath of a traumatic event have not been studied. METHODS Twenty-two motor vehicle collision survivors and 12 nontraumatized control subjects participated. Regional cerebral blood flow (rCBF) was measured using [(15)O]-H(2)O positron emission tomography (PET) at rest and as subjects listened to scripts of traumatic and neutral events. Self-report measures rated emotional responses to the scripts; standardized assessments (Impact of Events--Revised) evaluated acute stress symptoms at scanning and at 3-month follow-up. Most subjects improved symptomatically. RESULTS At rest, trauma subjects showed hyperperfusion in right mPFC/ACC and hypoperfusion in right amygdala compared with control subjects. In trauma subjects, listening to trauma scripts versus neutral scripts resulted in decreased flow in the right amygdala and left amygdala/perirhinal cortex, and symptom scores correlated negatively with right hippocampal flow changes. Symptom improvement at 3 months correlated negatively with rCBF changes in right perirhinal cortex and hippocampus during the trauma versus neutral script contrast. Subjective disturbance during the trauma versus neutral contrast correlated positively with rCBF changes in right amygdala and left mPFC. Functional connectivity analyses of rCBF changes during trauma versus neutral scripts demonstrated left amygdala coupling with right ACC and bilateral anterior insula, as well as coupling between the amygdala and contralateral hippocampus. CONCLUSIONS In recently traumatized subjects functional interactions between the amygdala, perirhinal cortex and ACC/mPFC that occur during exposure to traumatic reminders may underlie adaptive/recuperative processes.

Neural correlates of self-reflection in post-traumatic stress disorder

Bluhm RL, Frewen PA, Coupland NC, Densmore M, Schore AN, Lanius RA. Neural correlates of self‐reflection in post‐traumatic stress disorder.

Philosophy, ethics, medicine and health care: the urgent need for critical practice

Reader in Applied Philosophy, Department of Interdisciplinary Studies, MMU Cheshire, Crewe, UK Director, University of Toronto Joint Centre for Bioethics, Toronto, Ontario, Canada Assistant Professor, Department of Philosophy, University of Guelph, Guelph, Ontario, Canada Assistant Professor, Department of Philosophy and Religious Studies, Old Dominion University, Norfolk, Virginia, USA Assistant Professor, Department of Philosophy, Dalhousie University, Halifax, Nova Scotia, Canada

Some Observations on "Observational" Research

Evidence-based medicine (EBM) ranks different medical research methods on a hierarchy, at the top of which are randomized controlled trials (RCTs) and systematic reviews or meta-analyses of RCTs. Any study that does not randomly assign patients to a treatment or a control group is automatically placed at a lower level on the hierarchy. This article argues that what matters is whether the treatment and control groups are similar with respect to potential confounding factors, not whether they got that way through randomization. Moreover, nonrandomized studies tend to have other characteristics that make them useful sources of evidence, in that they tend to last longer and to enroll more patients than do randomized trials. Replacing the sharp dichotomy between randomized and nonrandomized studies with a continuum from “clean” studies (which have high internal validity but whose results do not readily generalize to clinical practice) to pragmatic studies (which are designed to more closely reflect clinical practice) would also make a place for outcomes research and research using clinical databases, which are not included in the current hierarchy of evidence but which can provide important information about the safety and efficacy of treatments.