Electrophysiological correlates of exemplar-specific processes in implicit and explicit memory

The present ERP study investigated the retrieval of task-irrelevant exemplar-specific information under implicit and explicit memory conditions. Subjects completed either an indirect memory test (a natural/artificial judgment) or a direct recognition memory test. Both test groups were presented with new items, identical repetitions, and perceptually different but conceptually similar exemplars of previously seen study objects. Implicit and explicit memory retrieval elicited clearly dissociable ERP components that were differentially affected by exemplar changes from study to test. In the indirect test, identical repetitions, but not different exemplars, elicited a significant ERP repetition priming effect. In contrast, both types of repeated objects gave rise to a reliable old/new effect in the direct test. The results corroborate that implicit and explicit memory fall back on distinct cognitive representation and, more importantly, indicate that these representations differ in the type of stimulus information stored. Implicit retrieval entailed obligatory access to exemplar-specific perceptual information, despite its being task irrelevant. In contrast, explicit retrieval proved to be more flexible with conceptual and perceptual information accessed according to task demands.     

Incompleteness and harm avoidance in OCD symptom dimensions

Incompleteness (INC) and harm avoidance (HA) are motivational core dimensions of OCD. While HA-related concepts (e.g., inflated responsibility, overestimation of threat) are a main focus of current cognitive-behavioural OCD research, there is also a renewed interest in INC feelings and "not just right experiences" with an inability to achieve "closure" concerning actions/perceptions. This study systematically examines the association of OCD symptom dimensions with INC and HA in a large clinical OCD sample (n=202). Hierarchical linear multiple regression analyses controlling for anxiety, depression and symptom severity demonstrated a unique association of symmetry/ordering and checking (but not of contamination/washing and obsessional thoughts) with INC, and of obsessional thoughts and checking with HA. Thus, in contrast with symmetry/ordering (predominantly INC-related) and obsessional thoughts (predominantly HA-related), checking was motivationally heterogeneous, i.e., associated with INC and HA to a comparable and substantial degree. Contamination/washing failed to show a unique association with HA in two of three analyses, and with INC in all three analyses. Symptom severity uniquely contributed to INC in two of three analyses, but not to HA. Clinically, our results indicate that a conceptualization of OCD as an anxiety disorder is too narrow.     

Individual,Housing, and Neighborhood Predictors of Psychological Integration Among Vulnerably Housed and Homeless Individuals

The current longitudinal study evaluated the individual, housing, and neighborhood characteristics predictive of feeling psychologically integrated within one's neighborhood among a population of homeless and vulnerably housed individuals. Participants were recruited at homeless shelters, meal programs, and rooming houses in Ottawa, Canada and participated in three in‐person interviews, each approximately 1 year apart. Prospective and cross‐sectional predictors of psychological integration at Follow‐up 1 and Follow‐up 2 were examined. There were 397 participants at baseline, 341 at Follow‐up 1 and 320 at Follow‐up 2. A hierarchical multiple regression uncovered several significant predictors of psychological integration. The most salient and common predictors were being older, having greater social support, living in high quality housing, and residing in a neighborhood with a positive impact. Implications for service provision and policy advancements are discussed.