Handedness and the fringe of consciousness: strong handers ruminate while mixed handers self-reflect

Previous research found that mixed handers (i.e., those that are more ambidextrous) were more likely than strong handers to update their beliefs (Niebauer, Aselage, & Schutte, 2002). It was assumed that this was due to greater degrees of communication between the two cerebral hemispheres in mixed handers. Niebauer and Garvey (2004) made connections between this model of updating beliefs and metacognitive processing. The current work proposes that variations in interhemispheric interaction (as measured by degree of handedness) contribute to differences in consciousness, specifically when consciousness is used in rumination versus the metacognitive task of self-reflection. Using the Rumination-Reflection Questionnaire (Trapnell & Campbell, 1999), predictions were supported such that strong handedness was associated with self-rumination; whereas, mixed handedness was associated with increased self-reflection p values<.01, (N=255). James's (1890) concept of the "fringe of consciousness" is used to make connections between metacognition, updating beliefs, and self-reflection. Several studies are reviewed suggesting that mixed handers experience fringe consciousness to a greater degree than strong handers.     

Human foraging behavior in a virtual environment

We have developed an experimental platform that allows a large number of human participants to interact in real time within a common virtual world. Within this environment, human participants foraged for resources distributed in two spatially separated pools. In addition to varying the relative replenishment rate for the two pools (50-50, 65-35, or 80-20), we manipulated whether the participants could see each other and the entire resource distribution or had their vision restricted to resources at their own location. Two empirical deviations from an optimal distribution of the participants were found. First, the participants were more scattered within a resource pool than the resources were themselves. Second, there was systematic underutilization of the richer pool. For example, the participants distributed themselves 73% and 27% to resource pools that had replenishment rates of 80% and 20%, respectively. In addition, there were oscillations in the harvesting rate of the pools across time, revealed by a Fourier analysis with prominent power near 50 sec per cycle. The suboptimalities and oscillations were more apparent when the locations of the participants and the food were not visible. Individual participant knowledge thus affects the efficiency with which a population of participants harvests resources.     

Reversal of motor learning in the vestibulo-ocular reflex in the absence of visual input

Motor learning in the vestibulo-ocular reflex (VOR) and eyeblink conditioning use similar neural circuitry, and they may use similar cellular plasticity mechanisms. Classically conditioned eyeblink responses undergo extinction after prolonged exposure to the conditioned stimulus in the absence of the unconditioned stimulus. We investigated the possibility that a process similar to extinction may reverse learned changes in the VOR. We induced a learned alteration of the VOR response in rhesus monkeys using magnifying or miniaturizing goggles, which caused head movements to be accompanied by visual image motion. After learning, head movements in the absence of visual stimulation caused a loss of the learned eye movement response. When the learned gain was low, this reversal of learning occurred only when head movements were delivered, and not when the head was held stationary in the absence of visual input, suggesting that this reversal is mediated by an active, extinction-like process.     

A replication of the MMPI-A PSY-5 scales and development of facet subscales

McNulty, Harkness, Ben-Porath and Williams recently developed Personality Psychopathology Five (PSY-5) scales for the Minnesota Multiphasic Personality Inventory-A (MMPI-A). This study examined these new scales in a sample of 545 adolescents receiving inpatient psychiatric treatment. Item-level principal components analyses were employed to determine the internal structure of each PSY-5 scale and to aid in the creation of facet subscales for each PSY-5 scale. Results suggest that the MMPI-A PSY-5 scales display adequate internal consistency and our findings generally replicate the original work of McNulty et al. but also extend this work by showing that several of the PSY-5 scales may also be subdivided into meaningful lower level dimensions. These facet subscales for each of the MMPI-A PSY-5 scales are offered for further study.     

An examination and replication of the psychometric properties of the Massachusetts Youth Screening Instrument--second edition (MAYSI-2) among adolescents in detention settings

There is a high prevalence of psychological disorders among adolescents in detention facilities. The need for a simple, effective screening tool led to the development of the Massachusetts Youth Screening Instrument (MAYSI) and its successor, the MAYSI-2. This study evaluated the MAYSI-2 psychometric properties based on the records of 704 youths evaluated at intake to detention facilities. In addition to factor structure, the study evaluated test-retest reliability and concurrent external validity. Results were generally encouraging in terms of the use of MAYSI-2 in detention facilities, and directions for future research are discussed.     

The Five-factor Personality Inventory as a measure of the Five-factor Model: Belgian, American, and Hungarian comparisons with the NEO-PI-R

The lexically based Five-Factor Personality Inventory (FFPI) was correlated with the factors and facets of the Revised NEO Personality Inventory (NEO-PI-R) in Belgian (N = 265), American (N = 116), and Hungarian (N = 320) samples. Results were similar across the three cultures. Analysis of orthogonalized FFPI factors showed that three of them--emotional stability, extraversion, and agreeableness--showed a direct correspondence to their NEO-PI-R counterparts. Autonomy, however, was not clearly related to openness, and facet analysis suggested that it might be interpreted as a dominance factor Better matches to NEO-PI-R conscientiousness and openness could be obtained by using vectors rotated 30 degrees from the FFPI positions. Raw scale scores showed similar results. Researchers should not assume that all measures of the Five-Factor Model are qualitatively similar     

An evaluation of the incremental validity of the MMPI-2 Superlative (S) scale in an inpatient psychiatric sample

The MMPI-2 Superlative (S) scale was developed by Butcher and Han (1995) to assess individuals' tendencies to present themselves in an unrealistically positive light. The current study examined the performance of the L, K, and S scales in accurately distinguishing the MMPI-2 profiles of 379 psychiatric inpatients who produced one or more elevations on the basic scale profiles, from 82 psychiatric inpatients who produced no clinical range elevation on any of the eight basic clinical scales (excluding scales 5 and 0). The findings from the present study indicate that the S scale appears to be effective in the identification of defensiveness among psychiatric inpatients, with mean effect sizes in the moderate to large range. The optimal T-score cutoff for identifying defensive responders was 70 for both men and women. Further, results of hierarchical regression analyses showed that the S scale added incrementally to the prediction levels achieved by the optimal combination of the L and K scales.     

On the delay-dependent involvement of the hippocampus in object recognition memory

The role of the hippocampus in object recognition memory processes is unclear in the current literature. Conflicting results have been found in lesion studies of both primates and rodents. Procedural differences between studies, such as retention interval, may explain these discrepancies. In the present study, acute lidocaine administration was used to temporarily inactivate the hippocampus prior to training in the spontaneous object recognition task. Male C57BL/6J mice were administered bilateral lidocaine (4%, 0.5 microl/side) or aCSF (0.5 microl/side) directly into the CA1 region of the dorsal hippocampus 5 min prior to sample object training, and object recognition memory was tested after a short ( 5 min) or long (24 h) retention interval. There was no effect of intra-hippocampal lidocaine on the time needed for mice to accumulate sample object exploration, suggesting that inactivation of the hippocampus did not affect sample session activity or the motivation to explore objects. Lidocaine-treated mice exhibited impaired object recognition memory, measured as reduced novel object preference, after a 24 h but not a 5 min retention interval. These data support a delay-dependent role for the hippocampus in object recognition memory, an effect consistent with the results of hippocampal lesion studies conducted in rats. However, these data are also consistent with the view that the hippocampus is involved in object recognition memory regardless of retention interval, and that object recognition processes of parahippocampal structures (e.g., perirhinal cortex) are sufficient to support object recognition memory over short retention intervals.     

Treatment-resistant posttraumatic stress disorder: strategies for intervention

The mainstay of treatment for chronic posttraumatic stress disorder (PTSD) is a combination of psychotherapy and medication treatments. The first-line medications for PTSD are antidepressants, with two selective serotonin reuptake inhibitors (sertraline and paroxetine) currently Food and Drug Administration-indicated for PTSD. However, many patients do not have an adequate response to antidepressants, therefore, combinations with other antidepressants or with other classes of psychotropic medication are often utilized to enhance the therapeutic response. Other agents that have been used include mood stabilizers, anti-adrenergics, anxiolytics, and atypical antipsychotics. The heterogeneity of symptom clusters in PTSD as well as the complex psychiatric comorbidities (eg, with depression or substance abuse) further support the notion that combinations of medications may be needed. To date, there is a paucity of data to support specific strategies for augmenting antidepressants in PTSD. This review will address representative existing studies and discuss several potential pharmacologic strategies for patients suffering from treatment-refractory PTSD.