Traumatic memories: bridging the gap between functional neuroimaging and psychotherapy

Objective: Neuroimaging studies have highlighted important issues related to structural and functional brain changes found in sufferers of psychological trauma that may influence their ability to synthesize, categorize, and integrate traumatic memories. Methods: Literature review and critical analysis and synthesis. Results: Traumatic memories are diagnostic symptoms of post-traumatic stress disorder (PTSD), and the dual representation theory posits separate memory systems subserving vivid re-experiencing (non-hippocampally dependent) versus declarative autobiographical memories of trauma (hippocampally dependent). But the psychopathological signs of trauma are not static over time, nor is the expression of traumatic memories. Multiple memory systems are activated simultaneously and in parallel on various occasions. Neural circuitry interaction is a crucial aspect in the development of a psychotherapeutic approach that may favour an integrative translation of the sensory fragments of the traumatic memory into a declarative memory system. Conclusion: The relationship between neuroimaging findings and psychological approaches is discussed for greater efficacy in the treatment of psychologically traumatized patients.

Two important but almost never related beliefs

Engelmann believes in two general strong beliefs. On one side, Engelmann believes in probabilistic skepticism. That the existence has its maximum probability or there is no existence at all is not possible. The other probabilities of existence are always possible. On the other hand, instead of elements that constitute a beginning arrived at by an unknown division, the Gestalt theory begins with wholes or Gestalten. These Gestalten can be divided in parts but each part can be only a part of his specific Gestalt. The majority of probabilistic skeptics and the majority of Gestalt theory followers do not believe they can be together accepted. On the contrary Engelmann is a member of a small group that both beliefs occur simultaneously. Bibace`s questions were each answered by Engelmann. In some questions Engelmann harmonize with Bibace, in others they disagree.

Cold Shock Genes cspA and cspB from Caulobacter crescentus Are Posttranscriptionally Regulated and Important for Cold Adaptation

Cold shock proteins (CSPs) are nucleic acid binding chaperones, first described as being induced to solve the problem of mRNA stabilization after temperature downshift. Caulobacter crescentus has four CSPs: CspA and CspB, which are cold induced, and CspC and CspD, which are induced only in stationary phase. In this work we have determined that the synthesis of both CspA and CspB reaches the maximum levels early in the acclimation phase. The deletion of cspA causes a decrease in growth at low temperature, whereas the strain with a deletion of cspB has a very subtle and transient cold-related growth phenotype. The cspA cspB double mutant has a slightly more severe phenotype than that of the cspA mutant, suggesting that although CspA may be more important to cold adaptation than CspB, both proteins have a role in this process. Gene expression analyses were carried out using cspA and cspB regulatory fusions to the lacZ reporter gene and showed that both genes are regulated at the transcriptional and posttranscriptional levels. Deletion mapping of the long 5'-untranslated region (5'-UTR) of each gene identified a common region important for cold induction, probably via translation enhancement. In contrast to what was reported for other bacteria, these cold shock genes have no regulatory regions downstream from ATG that are important for cold induction. This work shows that the importance of CspA and CspB to C. crescentus cold adaptation, mechanisms of regulation, and pattern of expression during the acclimation phase apparently differs in many aspects from what has been described so far for other bacteria.

Leishmania amazonensis Arginase Compartmentalization in the Glycosome Is Important for Parasite Infectivity

In Leishmania, de novo polyamine synthesis is initiated by the cleavage of L-arginine to urea and L-ornithine by the action of arginase (ARG, E.C. 3.5.3.1). Previous studies in L. major and L. mexicana showed that ARG is essential for in vitro growth in the absence of polyamines and needed for full infectivity in animal infections. The ARG protein is normally found within the parasite glycosome, and here we examined whether this localization is required for survival and infectivity. First, the localization of L. amazonensis ARG in the glycosome was confirmed in both the promastigote and amastigote stages. As in other species, arg(-) L. amazonensis required putrescine for growth and presented an attenuated infectivity. Restoration of a wild type ARG to the arg(-) mutant restored ARG expression, growth and infectivity. In contrast, restoration of a cytosol-targeted ARG lacking the glycosomal SKL targeting sequence (arg Delta SKL) restored growth but failed to restore infectivity. Further study showed that the ARG Delta SKL protein was found in the cytosol as expected, but at very low levels. Our results indicate that the proper compartmentalization of L. amazonensis arginase in the glycosome is important for enzyme activity and optimal infectivity. Our conjecture is that parasite arginase participates in a complex equilibrium that defines the fate of L-arginine and that its proper subcellular location may be essential for this physiological orchestration.

The Pst system of Streptococcus mutans is important for phosphate transport and adhesion to abiotic surfaces

The Pst system is a high-affinity inorganic phosphate transporter found in many bacterial species. Streptococcus mutans, the etiological agent of tooth decay, carries a single copy of the pst operon composed of six cistrons (pstS, pstC1, pstC, pstB, smu.1134 and phoU). Here, we show that deletion of pstS, encoding the phosphate-binding protein, reduces phosphate uptake and impairs cell growth, which can be restored upon enrichment of the medium with high concentrations of inorganic phosphate. The relevance of Pst for growth was also demonstrated in the wild-type strain treated with an anti-PstS antibody. Nevertheless, a reduced ability to bind to saliva-coated surfaces was observed, along with the reduction of extracellular polysaccharide production, although no difference on pH acidification was observed between mutant and wild-type strains. Taken together, the present data indicate that the S.similar to mutans Pst system participates in phosphate uptake, cell growth and expression of virulence-associated traits.

Spectral characteristics of the hippocampal LFP during contextual fear conditioning

OBJECTIVE: The hippocampus has an important role in the acquisition and recall of aversive memories. The objective of this study was to investigate the relationship among hippocampal rhythms. METHODS: Microeletrodes arrays were implanted in the hippocampus of Wistar rats. The animals were trained and tested in a contextual fear conditioning task. The training consisted in applying shocks in the legs. The memory test was performed 1 day (recent memory) or 18 days (remote memory) after training. We proposed a measure based on the FFT power spectrum, denominated "delta-theta ratio", to characterize the different behaviors (active exploration and freezing) and the memories types. RESULTS: The delta-theta ratio was able to distinguish recent and remote memories. In this study, the ratio for the 18-day group was smaller than for the 1-day group. Moreover, this measure was useful to distinguish the different behavior states active exploration and freezing. CONCLUSIONS: The results suggest delta-theta oscillations could reflect the demands on information processing during recent and remote memory recalls.

Which factors are important for crossmodal attentional effect?

Some results in the literature suggest that crossmodal attention is very sensitive to the features of the experimental protocol. The current work examined the possible contribution of the asynchrony between the onset of the cue and the target (SOA) and the kind of task performed by the observer to the manifestation of crossmodal attentional effect. In a first experiment, a target (Gabor patch), whose spatial frequency had to be discriminated, was presented 133 or 159 ms after an auditory cue, in a close location on the same side or in a distant location on the opposite side. The crossmodal attentional effect was observed only for the 159 ms SOA. In a second experiment, the SOA was again 133 ms, but the location of the target had to be discriminated, instead of its spatial frequency. A crossmodal attentional effect was observed. The results of these two experiments indicate that crossmodal attentional effect depends on the SOA and the task. It takes longer to develop when the task requires the discrimination of the spatial frequency of the target than the discrimination of its location.