Bilingual corpus callosum variability

Magnetic resonance imaging was used to produce midsagittal images of the corpus callosum of 19 right-handed adult male and female subjects. The preliminary findings of this study indicate that significant adaptation in the anterior midbody of the corpus callosum has occurred to accommodate multiple language capacity in bilingual individuals compared to monolingual individuals. The main interpretation of this finding is that the precentral gyrus is involved in bilingual faculty adaptation assuming a role consistent with the somatotopical input to areas dedicated to the mouth, and input to association tracts connecting the premotor and supplementary motor cortices. This paper discusses possible implications to neuroscientists, second language educators, and their students.     

Age differences in memory control: evidence from updating and retrieval-practice tasks

Some contemporary approaches suggest that inhibitory mechanisms play an important role in cognitive development. In addition, several authors distinguish between intentional and unintentional inhibitory processes in cognition. We report two experiments aimed at exploring possible developmental changes in these two types of inhibitory mechanisms. In Experiment 1, an updating task was used. This task requires that participants intentionally suppress irrelevant information from working memory. In Experiment 2, the retrieval-practice task was used. Retrieval practice of a subset of studied items is thought to involve unintentional inhibitory processes to overcome interference from competing memories. As a result, suppressed items become forgotten in a later memory test. Results of the experiments indicated that younger children (8) were less efficient than older children (12) and adults at intentionally suppressing information (updating task). However, when the task required unintentional inhibition of competing items (retrieval-practice task), this developmental trend was not found and children and adults showed similar levels of retrieval-induced forgetting. The results are discussed in terms of the development of efficient inhibition and the distinction between intentional and unintentional inhibitions.     

The perception of visually presented yaw and pitch turns: assessing the contribution of motion, static, and cognitive cues

Terrestrial gravity restricts human locomotion to surfaces in which turns involve rotationsaround the body axis. Because observers are usually upright, one might expect the effects of gravity to induce differences in the processing of vertical versus horizontal turns. Subjects observed visual scenes of bending tunnels, either statically or dynamically, as if they were moving passively through the visual scene and were then asked to reproduce the turn deviation of the tunnel with a trackball. In order to disentangle inertia-related (earth-centered) from vision-related (body-centered) factors, the subjects were either upright or lying on their right side during the observations. Furthermore, the availability of continuous optic flow, geometrical cues, and eye movement were manipulated in three experiments. The results allowed us to characterize the factors' contributions as follows. Forward turns (pitch down) with all cues were largely overestimated, as compared with backward turns (pitch up). First, eye movements known to be irregular for vertical stimulation were largely responsible for this asymmetry. Second, geometry-based estimations are, to some extent, asymmetrical. Third, a cognitive effect corresponding to the evaluation of navigability for upward and downward turns was found (i.e.,top-down influences, such as the fear of falling often reported), which tended to increase the estimation of turns in the direction of gravity.     

Religiosity/spirituality and health. A critical review of the evidence for biological pathways

The authors review evidence regarding the biological processes that may link religiosity/spirituality to health. A growing body of observational evidence supports the hypothesis that links religiosity/spirituality to physiological processes. Although much of the earliest evidence came from cross-sectional studies with questionable generalizability and potential confounding, more recent research, with more representative samples and multivariate analysis, provides stronger evidence linking Judeo-Christian religious practices to blood pressure and immune function. The strongest evidence comes from randomized interventional trials reporting the beneficial physiological impact of meditation (primarily transcendental meditation). Overall, available evidence is generally consistent with the hypothesis that religiosity/spirituality is linked to health-related physiological processes--including cardiovascular, neuroendocrine, and immune function--althogh more solid evidence is needed.     

Effects of acute, repeated and chronic variable stress on in vivo tyrosine hydroxylase activity and on alpha(2)-adrenoceptor sensitivity in the rat brain

We assessed the effects of a single tail pinch and two chronic stress regimes, repeated and variable, on in vivo tyrosine hydroxylase activity and on alpha2-adrenoceptor sensitivity in two brain regions. After administering a 3,4-dihydroxyphenylalanine (DOPA) decarboxylase inhibitor, tyrosine hydroxylase activity, measured as the accumulation of DOPA, and noradrenaline (NA) content were determined by using high-performance liquid chromatography. A single tail pinch for 5 min induced an enhancement of DOPA content in hippocampus (28%) and hypothalamus (67%) which was still present 24 h later. This increase could account for the lack of changes in NA content in both regions after the application of this stressor. However, tyrosine hydroxylase activity was unmodified 24 h after exposure to both repeated (5 min of tail pinch, twice daily, for 14 days) and chronic variable stress (one of 5 different stressors, once daily, for 14 days) although there was an enhancement of NA levels in hippocampus (45 and 54%, respectively) and hypothalamus (24.5 and 36%, respectively). The sensitivity of the alpha2-adrenoceptors which regulate [3H]-NA release in hippocampal and hypothalamic synaptosomes was not modified by the acute or chronic stress protocols assayed. The results show that both paradigms of chronic stress had similar effects on the noradrenergic indices evaluated.     

Prior source exposure and persuasion: further evidence for misattributional processes

To assess the persuasive impact of prior source exposure, two studies paired persuasive messages with a source to whom participants had previously been exposed subliminally, explicitly, or not at all. In Experiment 2, participants' attention also was drawn to information that potentially undermined the implications of any reaction to re-exposure. Compared to no exposure, prior subliminal exposure increased the source's persuasiveness, an effect not mediated by source liking. Explicit exposure increased source persuasiveness to the extent that the source was liked more and only absent a recall cue. Results favored misattributional accounts of prior exposure effects.     

The impact of father absence on adolescent separation-individuation

The authors compared separation-individuation and psychological separation from fathers of 25 adolescent boys who were living with both biological parents with that of 25 boys who were living with their biological mothers in homes in which the fathers did not reside. The results showed that the boys in the 2 groups did not differ on measures of separation-individuation and that the quality of the mother-son relationship mediated several of the assessed separation-individuation manifestations. The authors' initial data analysis with regard to psychological separation showed that boys who lived in homes in which the father was a nonresident were more separated on 2 of the 4 dimensions assessed; however, when controlled for quality of mother-son and father-son relationship, these differences were not significant. The frequency of father contact in homes in which the father did not reside was positively correlated with healthy separation but negatively correlated with functional, attitudinal, and emotional independence from the father. The results of the study support the importance of the quality of a child's relationship with his or her mother and father as a mediator of several dimensions of the separation-individuation process.     

Retrieval-induced forgetting in perceptually driven memory tests

Recent data (T. J. Perfect, C. J. A. Moulin, M. A. Conway, & E. Perry, 2002) have suggested that retrieval-induced forgetting (RIF) depends on conceptual memory because the effect is not found in perceptually driven tasks. In 3 experiments, the authors aimed to show that the presence of RIF depends on whether the procedure induces appropriate transfer between representations and competition rather than on the nature of the final test. The authors adapted the standard paradigm to introduce lexical categories (words that shared the first 2 letters) at study and practice. Direct and indirect fragment completion tests were used at retrieval. The results showed significant RIF effects in perceptually driven tasks. Furthermore, they indicated that the presence of RIF effects depended on using adequate cuing to induce competition during the retrieval practice and on the final memory test tapping the inhibited representation.     

Interactive patterns detection in family communication with adolescents

Interactive patterns detection in family communication with adolescents. Nondistant communication is a relevant indicator for family functionality valuation. The goal of this study is to analyze this communication in order to identify specific kinds of leadership, interaction patterns and the relation between verbal and nonverbal elements in communication. The observational design exposed is an idiographic one, punctual and multidimensional, which uses field format as observation instrument. Participants were seven standardized families made up of both ancestors and an adolescent son or daughter. According to the family models analyzed, results show a predominantly democratic communication style in adults with recurrent support expressions. The sequential analysis incorporates only categories from the emitter point of view, and detects relevant sequences which show symmetric interaction between all three family members. Verbal and nonverbal channels provide complementary information. Depending on adolescents' gender different patterns in behaviour can be identified as well.