Alternate response preparation in a visuomotor serial task

The preparation of a particular motor pattern is related to the information available that enables the actor to predict the correct response to a forthcoming stimulus. In many situations, however, prediction is not possible. In such cases, the individual can guess the probable parameters of the next stimulus. The authors attempted to establish the bias in the motor intention for movement and its interaction with a possible memory trace of the stimulus-response mapping produced by the preceding stimulus. Two letters were presented bilaterally, and participants (N=21) had to discriminate the target letter and respond with the compatible hand. The present findings support the existence of a memory trace of the previous stimulus-response mapping.     

An evaluation scale of family environment for identification of children at risk of school failure

This study describes the development of the Home Environment Resources Scale, a Brazilian measure for families with children ages 6 to 12 years. The scale measures aspects of support for school achievement, made available to the child at home. A first version of the measure with 11 subscales was administered to 100 mothers or guardians of children with poor school achievement in a clinical setting. Analysis of the items in the first version resulted in a final version comprising 8 subscales with acceptable indices of internal consistency. Two validity studies were conducted. One aimed at verifying to what extent the Home Environment Resources Scale could discriminate the home environment of students referred to a mental health clinic on account of poor school performance. The sample included mothers of 53 referred and 23 nonreferred children. The two groups differed significantly in home resources and on four subscales. The other study assessed the validity, i.e., prediction of the academic outcome of children entering Grade 1. 70 children and their mothers participated. Results indicate that school achievement and social competence at school are mediated by family support.     

Mother-infant relationships in baboons (Papio hamadryas): predictors of differences and discontinuities in developmental pathways

This study uses hierarchical linear regression modeling to analyze sources of variation in the developmental pathways of mother-infant relationships and to search for behavioral discontinuities. The data come from 23 mother-infant dyads of baboons (Papio hamadryas), whose interactions were recorded longitudinally during the infants' 1st year of life. The infant's sex and the mother's age and reproductive experience accounted for part of the variation observed in the developmental pathways of 11 of 20 behavioral measures analyzed; however, some of them did so only in some periods but not in others. The authors proposed that this can reflect the occurrence of reorganizations or discontinuities in the mother-infant relationship that can be related to important life events such as the mother's resumption of sexual activity.     

Activation of adenosine receptors in the posterior cingulate cortex impairs memory retrieval in the rat

Adenosine A1 and A2A receptor agonists and antagonists have been reported to alter learning and memory. The aim of our study was to investigate the involvement of adenosinergic system in memory retrieval into posterior cingulate cortex (PCC) of Wistar rats. To clarify this question, we tested specifics agonist and antagonists of adenosine A1 and A2A receptors in rats submitted to a one-trial inhibitory avoidance task. The stimulation of adenosine A1 and A2A receptors by CPA and CGS21680, respectively, impaired memory retrieval for inhibitory avoidance task, into PCC. These findings provide behavioral evidence for the role of adenosinergic system in the memory retrieval into PCC.     

Fragile X mental retardation protein levels increase following complex environment exposure in rat brain regions undergoing active synaptogenesis

Fragile X mental retardation protein (FMRP), which is absent in fragile X syndrome, is synthesized in vitro in response to neurotransmitter activation. Humans and mice lacking FMRP exhibit abnormal dendritic spine development, suggesting that this protein plays an important role in synaptic plasticity. Previously, our laboratory demonstrated increased FMRP immunoreactivity in visual cortex of rats exposed to complex environments (EC) and in motor cortex of rats trained on motor-skill tasks compared with animals reared individually in standard laboratory housing (IC). Here, we use immunohistochemistry to extend those findings by investigating FMRP levels in visual cortex and hippocampal dentate gyrus of animals exposed to EC or IC. Rats exposed to EC for 20 days exhibited increased FMRP immunoreactivity in visual cortex compared with animals housed in standard laboratory caging. In the dentate gyrus, animals exposed to EC for 20 days had higher FMRP levels than animals exposed to EC for 5 or 10 days. In light of possible antibody crossreactivity with closely related proteins FXR1P and FXR2P, FMRP immunoreactivity in the posterior-dorsal one-third of cerebral cortex was also examined by Western blotting following 20 days of EC exposure. FMRP levels were greater in EC animals, whereas levels of FXR1P and FXR2P were unaffected by experience. These results provide further evidence for behaviorally induced alteration of FMRP expression in contrast to its homologues, extend previous findings suggesting regulation of its expression by synaptic activity, and support the theories associating FMRP expression with alteration of synaptic structure both in development and later in the life-cycle.     

Trust in testimony: children's use of true and false statements

The extent to which young children monitor and use the truth of assertions to gauge the reliability of subsequent testimony was examined. Three- and 4-year-old children were presented with two informants, an accurate labeler and an inaccurate labeler. They were then invited to learn names for novel objects from these informants. The children correctly monitored and identified the informants on the basis of the truth of their prior labeling. Furthermore, children who explicitly identified the unreliable or reliable informant across two tasks went on to demonstrate selective trust in the novel information provided by the previously reliable informant. Children who did not consistently identify the unreliable or reliable informant proved indiscriminate.     

Gestural imitation and limb apraxia in corticobasal degeneration

Limb apraxia is a common symptom of corticobasal degeneration (CBD). While previous research has shown that individuals with CBD have difficulty imitating transitive (tool-use actions) and intransitive non-representational gestures (nonsense actions), intransitive representational gestures (actions without a tool) have not been examined. In the current study, eight individuals with CBD and eight age-matched healthy adults performed transitive, intransitive representational and intransitive non-representational gestures to imitation. The results indicated that compared to controls, individuals with CBD were significantly less accurate in the imitation of transitive and intransitive non-representational gestures but showed no deficits for the imitation of intransitive representational gestures. This advantage for intransitive representational gestures was thought to be due to fewer demands being placed on the analysis of visual-gestural information or the translation of this information into movement when imitating these gestures. These findings speak to the importance of context and the representation of gestures in memory in gesture performance.     

Processing of temporal information: Evidence from eye movements

In two experiments, we recorded eye movements to study how readers monitor temporal order information contained in narrative texts. Participants read short texts containing critical temporal information in the sixth sentence, which could be either consistent or inconsistent with temporal order information given in the second sentence. In Experiment 1, inconsistent sentences yielded more regressions to the second sentence and longer refixations of it. In Experiment 2, this pattern of eye movements was shown only by readers who noticed the inconsistency and were able to report it. Theoretical and methodological implications of the results for research on text comprehension are discussed.     

Orienting in space and time: Joint contributions to exogenous spatial cuing effects

We examined whether the time course of exogenous spatial-cuing effects is sensitive to the allocation of attention in time. Expectation for a target within a particular time window following the cue was manipulated by varying the proportion of trials that appeared at each of three stimulus onset asynchronies in both a detection task and a two-alternative forced-choice discrimination task. The time course of spatial-cuing effects was sensitive to the temporal expectation manipulation only in the discrimination task. The results are discussed with reference to the role of attentional set in exogenous spatialcuing paradigms.     

Thinking of you: nonconscious pursuit of interpersonal goals associated with relationship partners

The mere psychological presence of relationship partners was hypothesized to trigger interpersonal goals that are then pursued nonconsciously. Qualitative data suggested that people tend to pursue different interpersonal goals within different types of relationships (e.g., mother, best friend, coworker). In several studies, priming participants' relationship representations produced goal-directed behavior (achievement, helping, understanding) in line with the previously assessed goal content of those representations. These findings support the hypothesis that interpersonal goals are component features of relationship representations and that mere activation of those representations, even in the partner's physical absence, causes the goals to become active and to guide behavior nonconsciously within the current situation.