Familiarity and recollection vs representational models of medial temporal lobe structures: A single-case study.

Although it is known that medial temporal lobe (MTL) structures support declarative memory, the fact these structures have different architectonics and circuitry suggests they may also play different functional roles. Selective lesions of MTL structures offer an opportunity to understand these roles. We report, in this study, on JMG, a patient who presents highly unusual lesions that completely affected all MTL structures except for the right hippocampus and parts of neighbouring medial parahippocampal cortex. We first demonstrate that JMG shows preserved recall for visual material on 5 experimental tasks. This finding suggests that his right hippocampus is functional, even though it appears largely disconnected from most of its MTL afferents. In contrast, JMG performed very poorly, as compared to control subjects, on 7 tasks of visual recognition memory for single items. Although he sometimes performed above chance, neither familiarity nor recollection appeared fully preserved. These results indicate that extrahippocampal structures, damaged bilaterally in JMG, perform critical operations for item recognition; and that the hippocampus cannot take over that role, including recollection, when these structures are largely damaged. Finally, in a set of 3 recognition memory tasks with scenes as stimuli, JMG performed at the level of control participants and obtained normal indices of familiarity and recollection. Overall, our findings suggest that the right hippocampus and remnants of parahippocampal cortex can support recognition memory for scenes in the absence of preserved item-recognition memory. The patterns of dissociations, which we report in the present study, provide support for a representational account of the functional organization of MTL structures.

Symptoms Moderating the Association Between Recent Suicide Attempts and Trauma Levels: Fan-Shaped Effects.

The present study focuses on variables moderating the incidence of recent suicide attempt in a large community sample (n = 39,617) of French citizens with various levels of trauma. Five trauma levels were established based on posttraumatic stress disorder items of the Mini International Neuropsychiatric Interview. Twenty-three symptoms were examined as potential moderating variables with a fan-shaped pattern. Seven symptoms regarding desire for death, self-harm intention, suicidal ideation, lifetime suicide attempt, depressed mood, loss of interest, and panic attack exhibited the fan-shaped pattern. The absence of these moderating symptoms decreases the incidence of suicide attempt and their presence leads to a gradual increase.

Course of posttraumatic stress symptoms over the 5 years following an industrial disaster: a structural equation modeling study.

The present study examined individual latent changes in posttraumatic stress disorder (PTSD) symptoms over a 60-month period after an industrial disaster. Participants were recruited from survivors of a factory explosion. Participants were assessed retrospectively for peritraumatic reactions and acute stress symptoms. Posttraumatic stress disorder symptoms were then assessed at 6, 15, and 60 months. Using structural equation modeling, the authors tested 3 hypotheses of individual latent change: stability of PTSD symptoms between 6, 15, and 60 months; change between 6 and 15 months; and change between 15 and 60 months. Only one model provided a good fit suggesting that PTSD symptoms evolved between 6 and 15 months after trauma exposure and remained stable at the individual level thereafter.

Do balanced scales assess bipolar constructs? The case of the STAI scales.

Balanced scales, that is, scales based on items whose content is either negatively or positively polarized, are often used in the hope of measuring a bipolar construct. Research has shown that usually balanced scales do not yield 1-dimensional measurements. This threatens their construct validity. The authors show how to test bipolarity while accounting for method effects. This is demonstrated on a data set of state and trait anxiety measured with the State-Trait Anxiety Inventory (STAI; C. D. Spielberger, R. L. Gorsuch, R. Lushene, P. R. Vagg, & G. A. Jacobs, 1983) scales. Taking a test-retest perspective, assuming temporally stable method effects, the authors tested the bipolarity of the temporal change through suitable constraints specified in a structural equation model adapted from S. Vautier, R. Steyer, and A. Boomsma (2008). The model fit the data closely, chi(2)(13, N = 888) = 20.75, p = .07. Thus, the state and trait scales seem to measure bipolar constructs plus temporally stable method effects. Parameter estimates suggest reliable change scores for the state anxiety scale (rho = .90) and specific method effects for the state and trait scales of the STAI.

The true-change model with individual method effects: reliability issues.

The true intra-individual change model is generalized by defining individual method effects. This allows the analysis of non-congeneric test-retest variables assumed to measure a common, possibly (temporally) transient, attribute. Temporal change in the attribute between different times of measurement is modelled by the true-change variable. Individual causal method effects, due to heterogeneity of the measurement methods, account for the imperfect correlation of the true-score variables at each time of measurement. The reliability of the composite scores, at each time of measurement, and the reliability of the difference composite score may be estimated with appropriate coefficients derived from the model. Measurements of daily life tension in adult females serve to illustrate how the model can be used empirically.

A mixed Rasch model of dual-process conditional reasoning.

A fine-grained dual-process approach to conditional reasoning is advocated: Responses to conditional syllogisms are reached through the operation of either one of two systems, each of which can rely on two different mechanisms. System1 relies either on pragmatic implicatures or on the retrieval of information from semantic memory; System2 operates first through inhibition of System1, then (but not always) through activation of analytical processes. It follows that reasoners will fall into one of four groups of increasing reasoning ability, each group being uniquely characterized by (a) the modal pattern of individual answers to blocks of affirming the consequent (AC), denying the antecedent (DA), and modus tollens (MT) syllogisms featuring the same conditional; and (b) the average rate of determinate answers to AC, DA, and MT. This account receives indirect support from the extant literature and direct support from a mixed Rasch model of responses given to 18 syllogisms by 486 adult reasoners.

A longitudinal SEM approach to STAI data:two comprehensive multitrait-multistate models.

I investigated psychometric properties of data gathered with the State-Trait Anxiety Inventory (STAI; Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983, 1993) using structural equation modeling. Two features were integrated into the modeling: Bistability refers to the duality that is raised once the wording effect is recognized, and second-order, state-residual/trait decomposition refers to the basic bidimensionality of the data, which is revealed in a longitudinal perspective. I tested the approach on 2 samples of French adults (total N = 888) borrowed from Vautier and Jmel (2003). The models provided acceptable goodness of fit and supported the empirical need for hypothesizing 2 trait factors and 4 transient sources of true variance. I assessed the multidimensional composition of the composites using reliability analyses. I discuss theoretical consequences of the approach.

Transient error or specificity? An alternative to the staggered equivalent split-half procedure.

The data-based partial and complete reliability coefficients defined by G. Becker (2000) in his staggered equivalent split-half procedure (SESHP) were compared with the model-based specificity and consistency reliability coefficients defined by R. Steyer, M. J. Schmitt, and M. Eid (1999) in their latent state-trait model (LSTM). Partial reliability is based on coefficient alpha, which contains transient error. State and trait anxiety, measured using the State-Trait Anxiety Inventory on 2 occasions among French adults, illustrated both approaches. Theoretical and empirical analyses demonstrated that the specificity and consistency coefficients offer a testable alternative to the SESHP coefficients. In addition, dynamics of the state residual variance could be modeled and estimated in LSTM.

Measuring dynamic bipolarity in positive and negative activation.

The dynamic bipolarity of the positive and negative affective activation, measured with the PANAS scales, was studied using a pre-post design with an intervening experiment. The correlations between (a) the initial positive and negative constructs and (b) the respective change scores were estimated, random and systematic error being removed owing to a convenient structural equation modeling technique. Results demonstrated that a moderate perturbation may induce a medium correlation between latent change scores. Both strict dynamic independence and bipolarity were rejected. This result highlights the importance of individual differences in the way people perceive their affective changes. It is concluded that the PANAS two-factor model of affect provides only an approximate view of the structure and dynamics of mood.