Reduction in rat phosphatidylethanolamine binding protein-1 (PEBP1) after chronic corticosterone treatment may be paralleled by cognitive impairment: a first study

Chronic stress is associated with hippocampal atrophy and cognitive dysfunction. This study investigates how long-lasting administration of corticosterone as a mimic of experimentally induced stress affects psychometric performance and the expression of the phosphatidylethanolamine binding protein (PEBP1) in the adult hippocampus of one-year-old male rats. Psychometric investigations were conducted in rats before and after corticosterone treatment using a holeboard test system. Rats were randomly attributed to 2 groups (n = 7) for daily subcutaneous injection of either 26.8 mg/kg body weight corticosterone or sesame oil (vehicle control). Treatment was continued for 60 days, followed by cognitive retesting in the holeboard system. For protein analysis, the hippocampal proteome was separated by 2D electrophoresis (2DE) followed by image processing, statistical analysis, protein identification via peptide mass fingerprinting and gel matching and subsequent functional network mapping and molecular pathway analysis. Differential expression of PEBP1 was additionally quantified by Western blot analysis. Results show that chronic corticosterone significantly decreased rat hippocampal PEBP1 expression and induced a working and reference memory dysfunction. From this, we derive the preliminary hypothesis that PEBP1 may be a novel molecular mediator influencing cognitive integrity during chronic corticosterone exposure in rat hippocampus.     

Spatial updating in virtual reality: the sufficiency of visual information

Robust and effortless spatial orientation critically relies on "automatic and obligatory spatial updating", a largely automatized and reflex-like process that transforms our mental egocentric representation of the immediate surroundings during ego-motions. A rapid pointing paradigm was used to assess automatic/obligatory spatial updating after visually displayed upright rotations with or without concomitant physical rotations using a motion platform. Visual stimuli displaying a natural, subject-known scene proved sufficient for enabling automatic and obligatory spatial updating, irrespective of concurrent physical motions. This challenges the prevailing notion that visual cues alone are insufficient for enabling such spatial updating of rotations, and that vestibular/proprioceptive cues are both required and sufficient. Displaying optic flow devoid of landmarks during the motion and pointing phase was insufficient for enabling automatic spatial updating, but could not be entirely ignored either. Interestingly, additional physical motion cues hardly improved performance, and were insufficient for affording automatic spatial updating. The results are discussed in the context of the mental transformation hypothesis and the sensorimotor interference hypothesis, which associates difficulties in imagined perspective switches to interference between the sensorimotor and cognitive (to-be-imagined) perspective.     

Investigating the influence of continuous babble on auditory short-term memory performance

A number of factors could explain the adverse effect that babble noise has on memory for spoken words (Murphy, Craik, Li, & Schneider, 2000). Babble could degrade the perceptual representation of words to such an extent that it compromises their subsequent processing, or the presence of speech noise in the period between word presentations could interfere with rehearsal. Thirdly, the top-down processes needed to extract the words from the babble could draw on resources that otherwise would be used for encoding. We tested all these hypotheses by presenting babble either only during word presentation or rehearsal, or by gating the babble on and off 500 ms before and after each word pair. Only the last condition led to a decline in memory. We propose that this decline in memory occurred because participants were focusing their attention on the auditory stream (to enable them to better segregate the words from the noise background) rather than on remembering the words they had heard. To further support our claim we show that a similar memory deficit results when participants perform the same memory task in quiet together with a nonauditory attention-demanding secondary task.     

Children of Prenatally Depressed Mothers: Externalizing and Internalizing Symptoms are Accompanied by Reductions in Specific Social-Emotional Competencies

Studies have shown that child development is negatively affected by prenatal depression. A dysregulated hypothalamic-pituitary-adrenal axis in the pregnant woman, passed to the fetus, is one discussed key mechanism. Studies, investigating primary-school age children, have found effects on antisocial behavior. Effects on internalizing symptoms were not found, but the analysis did not distinguish between anxiety and depression symptoms. Additionally, until now, no objective test data operationalizing social-emotional competencies have been included. The present study examined: 1.Whether the effects on child externalizing symptoms could be replicated; 2. If there are specific effects on child internalizing symptoms, separated for anxiety and depression; and 3. Are child clinical symptoms reflected in reductions in social-emotional competencies. A sample of 61 prenatally depressed and 143 prenatally not-depressed women and their 6–9 year old children were compared, controlling for key confounders in both the perinatal period and in middle childhood. Children of prenatally depressed mothers had more antisocial behavior and depression symptoms reported by their mothers. The prediction of antisocial behavior scores tended to be more significant for boys than for girls. Child anxiety symptoms were primarily explained by current maternal depressive symptoms. Children of prenatally depressed mothers also showed a reduction in social-emotional competencies, specifically regarding the ability to interpret complex social situations. This study showed that, even in a non-clinical sample, there are distinct effects of prenatal depression on child externalizing and internalizing symptoms which are accompanied by reductions in specific social-emotional competencies. These results emphasize that treatment for depressed pregnant women and/or early support for affected families is worthwhile. Additional work is required to identify the underlying biological mechanisms.     

Interactions between view changes and shape changes in picture-picture matching

Four experiments are reported in which pictures of different morphs of novel, complex, 3-D objects, similar to objects which we must identify in the real world, were presented. We investigated how changes of viewpoint influence our ability to discriminate between morphs. View changes had a powerful effect on performance in picture-picture matching tasks when similarly shaped morphs had to be discriminated. Shape changes were detected faster and more accurately when morphs were depicted from the same rather than different views. In contrast, view change had no effect when dissimilarly shaped morphs had to be discriminated. This interaction between the effects of view change and shape change was found both for simultaneous stimulus presentation and for sequential presentation with interstimulus intervals up to 3600 ms. The interaction was found after repeated presentations of the stimuli before the matching task and after practice at the matching task as well as after no such pre-exposure to the stimuli or to the task. The results demonstrate the difficulty in activating abstract, view-insensitive representations to help to achieve object constancy, even when matching over long interstimulus intervals or after stimuli have already been seen many times.     

Some Useful 16-Valued Logics: How a Computer Network Should Think

In Belnaps useful 4-valued logic, the set 2={T,F} of classical truth values is generalized to the set 4=(2)={,{T},{F},{T,F}}. In the present paper, we argue in favor of extending this process to the set 16=(4) (and beyond). It turns out that this generalization is well-motivated and leads from the bilattice FOUR₂ with an information and a truth-and-falsity ordering to another algebraic structure, namely the trilattice SIXTEEN₃ with an information ordering together with a truth ordering and a (distinct) falsity ordering. Interestingly, the logics generated separately by the algebraic operations under the truth order and under the falsity order in SIXTEEN₃ coincide with the logic of FOUR₂, namely first degree entailment. This observation may be taken as a further indication of the significance of first degree entailment. In the present setting, however, it becomes rather natural to consider also logical systems in the language obtained by combining the vocabulary of the logic of the truth order and the falsity order. We semantically define the logics of the two orderings in the extended language and in both cases axiomatize a certain fragment comprising three unary operations: a negation, an involution, and their combination. We also suggest two other definitions of logics in the full language, including a bi-consequence system. In other words, in addition to presenting first degree entailment as a useful 16-valued logic, we define further useful 16-valued logics for reasoning about truth and (non-)falsity. We expect these logics to be an interesting and useful instrument in information processing, especially when we deal with a net of hierarchically interconnected computers. We also briefly discuss Arielis and Avrons notion of a logical bilattice and state a number of open problems for future research.Dedicated to Nuel D. Belnap on the occasion of his 75th Birthday     

Categorical perception of familiar objects

We report three experiments where the categorical perception of familiar, three-dimensional objects was investigated. A continuum of shape change between 15 pairs of objects was created and the images along the continuum were used as stimuli. In Experiment 1 participants were first required to discriminate pairs of images of objects that lay along the shape continuum. Then participants were asked to classify each morph-image into one of two pre-specified classes. We found evidence for categorical perception in some but not all of our object pairs. In Experiment 2 we varied the viewpoint of the objects in the discrimination task and found that effects of categorical perception generalized across changes in view. In Experiment 3 similarity ratings for each object pair were collected. These similarity scores correlated with the degree of perceptual categorization found for the object pairs. Our findings suggest that some familiar objects are perceived categorically and that categorical perception is closely tied to inter-object perceptual similarity.     

Combining linear-time temporal logic with constructiveness and paraconsistency

It is known that linear-time temporal logic (LTL), which is an extension of classical logic, is useful for expressing temporal reasoning as investigated in computer science. In this paper, two constructive and bounded versions of LTL, which are extensions of intuitionistic logic or Nelson's paraconsistent logic, are introduced as Gentzen-type sequent calculi. These logics, $\mathrm{IB}[l]$ and $\mathrm{PB}[l]$, are intended to provide a useful theoretical basis for representing not only temporal (linear-time), but also constructive, and paraconsistent (inconsistency-tolerant) reasoning. The time domain of the proposed logics is bounded by a fixed positive integer. Despite the restriction on the time domain, the logics can derive almost all the typical temporal axioms of LTL. As a merit of bounding time, faithful embeddings into intuitionistic logic and Nelson's paraconsistent logic are shown for $\mathrm{IB}[l]$ and $\mathrm{PB}[l]$, respectively. Completeness (with respect to Kripke semantics), cut–elimination, normalization (with respect to natural deduction), and decidability theorems for the newly defined logics are proved as the main results of this paper. Moreover, we present sound and complete display calculi for $\mathrm{IB}[l]$ and $\mathrm{PB}[l]$.In [P. Maier, Intuitionistic LTL and a new characterization of safety and liveness, in: Proceedings of Computer Science Logic 2004, in: Lecture Notes in Computer Science, vol. 3210, Springer-Verlag, Berlin, 2004, pp. 295–309] it has been emphasized that intuitionistic linear-time logic (ILTL) admits an elegant characterization of safety and liveness properties. The system ILTL, however, has been presented only in an algebraic setting. The present paper is the first semantical and proof-theoretical study of bounded constructive linear-time temporal logics containing either intuitionistic or strong negation.     

The eyes grasp,the hands see: Metric category knowledge transfers between vision and touch

Categorization of seen objects is often determined by the shapes of objects. However, shape is not exclusive to the visual modality: The haptic system also is expert at identifying shapes. Hence, an important question for understanding shape processing is whether humans store separate modality-dependent shape representations, or whether information is integrated into one multisensory representation. To answer this question, we created a metric space of computer-generated novel objects varying in shape. These objects were then printed using a 3-D printer, to generate tangible stimuli. In a categorization experiment, participants first explored the objects visually and haptically. We found that both modalities led to highly similar categorization behavior. Next, participants were trained either visually or haptically on shape categories within the metric space. As expected, visual training increased visual performance, and haptic training increased haptic performance. Importantly, however, we found that visual training also improved haptic performance, and vice versa. Two additional experiments showed that the location of the categorical boundary in the metric space also transferred across modalities, as did heightened discriminability of objects adjacent to the boundary. This observed transfer of metric category knowledge across modalities indicates that visual and haptic forms of shape information are integrated into a shared multisensory representation.