Todd A. Girard

Neurocircuitry models of posttraumatic stress disorder and beyond: a meta-analysis of functional neuroimaging studies.

Over the past two decades a relatively large number of studies have investigated the functional neuroanatomy of posttraumatic stress disorder (PTSD). However, findings are often inconsistent, thus challenging traditional neurocircuitry models of PTSD. As evidence mounts that cognition and behavior is an emergent property of interacting brain networks, the question arises whether PTSD can be understood by examining dysfunction in large-scale, spatially distributed neural networks. We used the activation likelihood estimation quantitative meta-analytic technique to synthesize findings across functional neuroimaging studies of PTSD that either used a non-trauma (N=20) or trauma-exposed (N=19) comparison control group. In line with neurocircuitry models, our findings support hyperactive amygdala and hypoactive medial prefrontal regions, but suggest hyperactive hippocampi. Characterization of additional regions under a triple network model showed functional alterations that largely overlapped with the salience network, central executive network, and default network. However, heterogeneity was observed within and across the neurocircuitry and triple network models, and between results based on comparisons to non-trauma and trauma-exposed control groups. Nonetheless, these results warrant further exploration of the neurocircuitry and large-scale network models in PTSD using connectivity analyses.

The body unbound: vestibular-motor hallucinations and out-of-body experiences.

Among the varied hallucinations associated with sleep paralysis (SP), out-of-body experiences (OBEs) and vestibular-motor (V-M) sensations represent a distinct factor. Recent studies of direct stimulation of vestibular cortex report a virtually identical set of bodily-self hallucinations. Both programs of research agree on numerous details of OBEs and V-M experiences and suggest similar hypotheses concerning their association. In the present study, self-report data from two on-line surveys of SP-related experiences were employed to assess hypotheses concerning the causal structure of relations among V-M experiences and OBEs during SP episodes. The results complement neurophysiological evidence and are consistent with the hypothesis that OBEs represent a breakdown in the normal binding of bodily-self sensations and suggest that out-of-body feelings (OBFs) are consequences of anomalous V-M experiences and precursors to a particular form of autoscopic experience, out-of-body autoscopy (OBA). An additional finding was that vestibular and motor experiences make relatively independent contributions to OBE variance. Although OBEs are superficially consistent with universal dualistic and supernatural intuitions about the nature of the soul and its relation to the body, recent research increasingly offers plausible alternative naturalistic explanations of the relevant phenomenology.

Paranoid delusions and threatening hallucinations: A prospective study of sleep paralysis experiences☆

Previously we reported a three-factor structure for hallucinations accompanying sleep paralysis (SP). These earlier analyses were, however, based on retrospective accounts. In a prospective study, 383 individuals reported individual episodes online providing further evidence for the three-factor structure as well as clearer conceptually meaningful relations among factors than retrospective studies. In addition, reports of individual episodes permitted a more fine-grained analysis of the internal structure of factors to assess predictions based on the hypothesis that a sensed or felt presence (FP) is a core experience affecting other SP hallucinations. Results were generally consistent with this hypothesis. In particular, associations among, and temporal stability of, sensory hallucinations were largely explained by their common association with FP. The findings are consistent with REM initiation of a threat activated vigilance system with pervasive effects on the SP experience and suggest a potential model for the thematic organization of nightmares and dreams more generally.

Executive Functioning in Children and Adolescents Prenatally Exposed to Alcohol: A Meta-Analytic Review

Prenatal alcohol exposure is associated with a constellation of adverse physical, neurocognitive and behavior outcomes, which comprise a continuum of disorders labeled Fetal Alcohol Spectrum Disorders (FASD). Extant research has consistently identified executive functions (EF) as a central impairment associated with FASD. Despite this, heterogeneity exists regarding the strength of the association between FASD and different EF, and this association has not yet been quantitatively synthesized. The current meta-analysis reviews 46 studies that compare children and adolescents with FASD to participants without FASD, on a variety of EF measures. In accordance with Miyake et al. Cognitive Psychology, 41, 49–100 (2000) three-factor model of EF, findings for the primary EF domains of working memory, inhibition, and set shifting are reviewed. Results indicate that children and adolescents with FASD demonstrate significant deficits across these EF, although the magnitude of effects diverged between EF, with working memory and inhibition yielding medium effects and set shifting yielding large effects. These results were moderated by sample characteristics, type of FASD diagnosis, and EF methodology. This quantitative synthesis offers novel future research directions.

Cumulative Childhood Maltreatment and Depression Among Incarcerated Youth Impulsivity and Hopelessness as Potential Intervening Variables

Youth involved in the juvenile justice system are at high risk for mental health problems, particularly depression. Furthermore, these youth often present with a history of childhood maltreatment. Despite research consistently demonstrating a link between childhood maltreatment and depression, our understanding of intervening factors of this relationship remains limited. This study examined impulsivity, hopelessness, and substance use as potential explanatory variables in the relationship between cumulative childhood maltreatment and depression severity among 110 incarcerated youth. The data were analyzed using path analysis. As hypothesized, cumulative maltreatment maintained a strong direct relation with depression severity in the context of the additional variables in the final model. Cumulative maltreatment also had an indirect relation with depression severity through both impulsivity and hopelessness. Contrary to expectation, substance use was not an explanatory variable in the model. These findings suggest that impulsivity and hopelessness might be important factors to consider in future studies on the relation between childhood maltreatment and depression symptoms among incarcerated youth.

Visual-spatial episodic memory in schizophrenia: A multiple systems framework.

OBJECTIVE Enhanced understanding of cognitive deficits, and the neurobiological abnormalities that mediate them, can be achieved through translational research that employs comparable experimental approaches across species. This study employed a multiple-systems framework derived from the rodent literature to investigate visual-spatial memory abilities associated with schizophrenia. METHOD Using the bin task, a human analog of rodent maze tasks, everyday objects were hidden in visually identical bins. Following a 1-min filled delay, participants with schizophrenia-spectrum disorders (n = 30) and healthy community controls (n = 30) were asked to identify both the object hidden and bin used on the basis of its spatial location. Three dimensions of visual-spatial memory were contrasted: (a) memory for spatial locations versus memory for objects, (b) allocentric (viewpoint independent) versus egocentric (body-centered) spatial representations, and (c) event (working) memory versus reference memory. RESULTS Most pronounced was a differential deficit in memory for spatial locations under allocentric (p = .005, d = -0.77) but not egocentric viewing conditions (p = .298, d = -0.28) in the schizophrenia group relative to healthy controls. Similarly, schizophrenia-related spatial memory deficits were pronounced under demands for event memory (p = .004, d = -0.77) but not reference memory (p = .171, d = -0.33). CONCLUSIONS These results support a heuristic of preferential deficits in hippocampal-mediated forms of memory in schizophrenia. Moreover, the task provides a useful paradigm for translational research and the pattern of deficits suggests that persons with schizophrenia may benefit from mnemonic approaches favoring egocentric representations and consistency when interacting with our visual-spatial world.

Comparison of WAIS-III Short Forms for Measuring Index and Full-Scale Scores.

This investigation assessed the ability of the Wechsler Adult Intelligence Scale—Third Edition (WAIS-III) short forms to estimate both index and IQ scores in a large, mixed clinical sample (N = 809). More specifically, a commonly used modification of Ward’s seven-subtest short form (SF7-A), a recently proposed index-based SF7-C and eight-subtest short form (SF8) were evaluated. All three SFs proved adequate for estimating verbal comprehension, perceptual organization, and full-scale intelligence within considerably less time relative to an SF11 that provides full measurement of WAIS index scores. The SF7-A provided the best combination overall in terms of psychometric performance and estimated time savings. However, SF8 best represents all four factors and allows measurement of processing speed. The SF7-C was most hampered by inclusion of the Block Design subtest in the current assessment, but may prove advantageous in future extensions to the WAIS-IV.

Health Care Provider Attitudes and Beliefs About People Living with HIV: Initial Validation of the Health Care Provider HIV/AIDS Stigma Scale (HPASS)

HIV stigma is a pressing concern for people living with HIV, and particularly when it is perpetuated by health care providers, as it may affect quality of life and access to health care services. The current study describes the development and initial validation of a contextually appropriate HIV stigma scale for health care providers in North America. A ground-up qualitative approach was used to develop the scale, and it was assessed psychometrically with health care trainees across Canada. The measure demonstrates excellent internal consistency reliability and test–retest reliability, as well as convergent and divergent validity. The study supports a tripartite model of HIV stigma consisting of stereotyping, prejudice and discrimination. The scale provides a new tool to assess HIV stigma in health care providers and can be used to inform training, intervention and self-evaluation of stigmatizing attitudes, beliefs and behaviors among providers.

Timing of spontaneous sleep‐paralysis episodes

The objective of this prospective naturalistic field study was to determine the distribution of naturally occurring sleep‐paralysis (SP) episodes over the course of nocturnal sleep and their relation to bedtimes. Regular SP experiencers (N = 348) who had previously filled out a screening assessment for SP as well as a general sleep survey were recruited. Participants reported, online over the World Wide Web, using a standard reporting form, bedtimes and subsequent latencies of spontaneous episodes of SP occurring in their homes shortly after their occurrence. The distribution of SP episodes over nights was skewed to the first 2 h following bedtime. Just over one quarter of SP episodes occurred within 1 h of bedtime, although episodes were reported throughout the night with a minor mode around the time of normal waking. SP latencies following bedtimes were moderately consistent across episodes and independent of bedtimes. Additionally, profiles of SP latencies validated self‐reported hypnagogic, hypnomesic, and hypnopompic SP categories, as occurring near the beginning, middle, and end of the night/sleep period respectively. Results are consistent with the hypothesis that SP timing is controlled by mechanisms initiated at or following sleep onset. These results also suggest that SP, rather than uniquely reflecting anomalous sleep‐onset rapid eye movement (REM) periods, may result from failure to maintain sleep during REM periods at any point during the sleep period. On this view, SP may sometimes reflect the maintenance of REM consciousness when waking and SP hallucinations the continuation of dream experiences into waking life.

Simulating real world functioning in schizophrenia using a naturalistic city environment and single-trial, goal-directed navigation

Objective: To develop a virtual reality platform that would serve as a functionally meaningful measure of cognition in schizophrenia and that would also complement standard batteries of cognitive tests during clinical trials for cognitive treatments in schizophrenia, be amenable to human neuroimaging research, yet lend itself to neurobiological comparison with rodent analogs. Method: Thirty-three patients with schizophrenia and 33 healthy controls matched for age, sex, video gaming experience, and education completed eight rapid, single-trial virtual navigation tasks within a naturalistic virtual city. Four trials tested their ability to find different targets seen during the passive viewing of a closed path that led them around different city blocks. Four subsequent trials tested their ability to return to four different starting points after viewing a path that took them several blocks away from the starting position. Results: Individuals with schizophrenia had difficulties in way-finding, measured as distance travelled to find targets previously encountered within the virtual city. They were also more likely not to notice the target during passive viewing, less likely to find novel shortcuts to targets, and more likely to become lost and fail completely in finding the target. Total travel distances across all eight trials strongly correlated (negatively) with neurocognitive measures and, for 49 participants who completed the Quality of Life Scale, psychosocial functioning. Conclusion: Single-trial, goal-directed navigation in a naturalistic virtual environment is a functionally meaningful measure of cognitive functioning in schizophrenia.