The scaling of postural adjustments during bimanual load-lifting in traumatic brain-injured adults

Previous postural studies of traumatic brain injury (TBI) patients have been limited to identifying deficits in static and quasi-dynamic postural control tasks such as weight shifting. In this study, we examined whether or not patients with TBI are able to scale adequately their postural adjustments during the performance of the dynamic task of bimanual load-lifting. An age matched group of healthy adults served as controls. We used the Tetrax posturography system that calculates a stability score (ST) based on fluctuations in vertical ground reaction forces, normalized for body weight. During quiet standing, the ST scores of the TBI group were significantly higher than the control group. Forward weight shift and percentage change in the vertical ground reaction forces (lift postural adjustment (LPA) and post-lift postural adjustment (PLPA) scores) linearly increased with increasing load weight in both healthy and TBI subjects. Group differences were found in the magnitude of forward weight shift but not in the relative increase of the LPA and PLPA scores during the lifting and post-lifting phases respectively. The forward weight shift of the TBI group was lower-than-normal and asymmetrical--there was significantly less forward weight shift on the more affected than on the less affected limb. In addition, a significant amplitude coupling was found between the scaling of the weight shift of the heel and forefoot of each limb. However, no coupling was found between the weight shift amplitudes of homologous parts of both limbs in the TBI group. The results showed that scaling based on prior experience was preserved in the TBI group, though some TBI subjects demonstrated absent scaling in either the more affected or less affected heel or forefoot. The differences between the normal and TBI groups in postural adjustments are not necessarily a sign of pathology; rather they may represent a deliberate choice of the central nervous system to counteract predictable disturbances.     

Evaluating psychological injury in motor vehicle accidents (MVA): development and validation of a protocol for detecting pretense

In order to assess the feigning ability of the psychological injury in a motor vehicle accident (MVA), a total of 105 subjects, which never had suffered a serious MVA and lay in psychopathology, responded to the MMPI-2 in line with the standard instructions. Thereafter, subjects were instructed to feign moral damage generated by a MVA prior to being evaluated using a clinical-forensic interview a week later, and responding to the MMPI-2 another week later. The results show that 60.9% of the subjects were able to effectively feign moral damage on the MMPI-2, and 3.8% in the forensic clinical interview. The analysis of the instruments and procedures for the validation of subject responses i.e., the original validity control scales of the MMPI-2 and the analysis of feigning strategies in the forensic clinical interview, revealed no efficacy in feigning detection. Nevertheless, collectively, all the control measures and procedures were effective for the detection of feigning. Therefore, a protocol for the detection of feigning of moral damage has been proposed.     

Priming effects on the N400 in the affective priming paradigm with facial expressions of emotion

We studied the effect of facial expression primes on the evaluation of target words through a variant of the affective priming paradigm. In order to make the affective valence of the faces irrelevant to the task, the participants were assigned a double prime–target task in which they were unpredictably asked either to identify the gender of the face or to evaluate whether the word was pleasant or unpleasant. Behavioral and electrophysiological (event-related potential, or ERP) indices of affective priming were analyzed. Temporal and spatial versions of principal components analyses were used to detect and quantify those ERP components associated with affective priming. Although no significant behavioral priming was observed, electrophysiological indices showed a reverse priming effect, in the sense that the amplitude of the N400 was higher in response to congruent than to incongruent negative words. Moreover, a late positive potential (LPP), peaking around 700 ms, was sensitive to affective valence but not to prime–target congruency. This pattern of results is consistent with previous accounts of ERP effects in the affective priming paradigm that have linked the LPP with evaluative priming and the N400 with semantic priming. Our proposed explanation of the N400 priming effects obtained in the present study is based on two assumptions: a double check of affective stimuli in terms of valence and specific emotion content, and the differential specificities of facial expressions of positive and negative emotions.     

Aggressive interactions and consistency of dominance hierarchies of the native and nonnative cichlid fishes of the Balsas basin

Dominance hierarchies are generally established based on the levels of aggressiveness that animals present. Frequently, animals fight to establish a dominance hierarchy and obtain a disputed resource. The Mexican mojarra Cichlasoma istlanum is a native species of the Balsas river basin and coexists there with four nonnative cichlids: tilapia Oreochromis sp., convict cichlid Amatitlania nigrofasciata, spotcheek cichlid Thorichthys maculipinnis, and green terror Andinoacara rivulatus. These five cichlid species compete for spaces for reproduction, feeding, and shelter and frequently engage in aggressive interactions to obtain these resources. We quantified dominance indices to evaluate the hierarchical structure of dominance among these five cichlids and the duration of aggressive behaviors of the Mexican mojarra during experimental contests between the native species and each of the four nonnative species. The Mexican mojarra was consistently dominant over the other four cichlid species, performing a larger number of aggressive behaviors and investing more time in attacking than the nonnative cichlids, which resulted in a higher hierarchical position. Our results show that the native fish, Mexican mojarra, established dominance over all four nonnative cichlid fish of the Balsas basin. Thus, the establishment of nonnative cichlid species in the Balsas basin is likely associated with factors other than behavioral dominance.     

Neighborhood and community factors: effects on deviant behavior and social competence

Socialization in a neighborhood and community at risk, defined in terms of violence, social alienation, school failure, and disruptive behavior, is a risk factor for the acquisition of antisocial and delinquent behavior. In order to test this hypothesis and examine the underlying mechanisms involved, 346 participants, 155 high-risk and 191 low-risk, aged 11 to 13, that is, under the age of criminal responsibility as established by the Spanish Law 5/2000 were selected. The results reveal that high-risk youngsters had higher rates of antisocial behavior and lower levels of social skills (i.e., greater tendency to externalize attribution of responsibility, fewer conflict resolution strategies, lower self esteem, and a lower degrees of emotional intelligence) in comparison to the lower-risk group. Finally, the results and implications of the study are discussed in the light of designing prevention programs.     

Mood state indicators for adolescent athletes based on POMS multidimensional model

In this paper, we offer a short version of the POMS, with only 33 items, designed to apply to young Spanish athletes. One hundred and six male soccer players, aged 14 and 15 years, participated in the study. In order to select the proposed items, we tried to maximize three criteria: (1) items should be understood by subjects, (2) items should be perceived as conceptually similar as possible to the meaning of their respective factors, and (3) every factor should contain at least 4 items. To meet the second criterion, PROXSCAL scaling procedure was used, which allowed retaining the items closest to the meaning of each factor. All goodness-of-fit indexes were satisfactory in all the proximity analyses performed. In the proposed POMS version, the 33 items refer to seven mood factors, as follows: Tension (4 items), Depression (9 items), Anger (4 items), Vigour (4 items), Fatigue (4 items), Confusion (4 items), and Friendliness (4 items).