Effects of dehydroepiandrosterone sulfate and progesterone on spatial learning and memory in young and aged mice

Young (2-4 months) and aged (14-16 months) male Swiss-Webster albino mice (n = 7 per group) were subcutaneously injected with 20 mg/kg/day dehydroepiandrosterone sulfate (DHEAS), progesterone (P), DHEAS + P, or vehicle control and trained over a 5-day period in a Morris water maze. The subjects were tested 48 hr after training for memory recall as measured by latencies to locate the hidden platform, and trunk blood was collected immediately thereafter. As expected, latency to platform decreased for all groups over the 6 testing days, with aged mice taking longer to reach platform than did young mice. However, results did not support the hypotheses that DHEAS-treated mice would exhibit shorter latencies and that P-treated mice would show longer latencies to platform in comparison with age-matched controls. These results raise doubts about the effectiveness of commercially available supplements claiming to promote enhanced memory in humans.     

"I no longer believe": did Freud abandon the seduction theory?

Recent accounts of the seduction theory and the question of its abandonment have emphasized the continuity of Freud's work before and after the seduction theory, claiming that Freud did not abandon his concern with the event of seduction but rather came to appreciate that an understanding of fantasy was also essential. This claim is challenged. It is shown that Freud did abandon the passionate concerns of his seduction theory for the most part; that he left behind his early interest in reconstructing unconscious infantile incest and focused instead on later, conscious seduction; that he at times clearly reduced apparent paternal incest to fantasy; that he turned away from the phenomenology of incest he had begun to develop; and that he theoretically nullified the value of the difference between real and fantasied seduction. It is also shown that, contrary to a persistent concern in psychoanalytic history, attention to actual seduction need not detract from the essential psychoanalytic concern with fantasy and infantile sexuality. Thinking about incest specifically illuminates the capacity for fantasizing, the core of the Freudian psyche. In this way the intuition of the seduction theory that there is something of distinctive psychoanalytic significance about incest finds support.     

Cognitive Control in Children with ADHD-C: How efficient are they?

The literature on children with attention deficit/hyperactivity disorder, combined type (ADHD-C), is currently inconclusive as to the nature of deficits in two forms of cognitive control — interference control and response selection (Nigg, 2006 Nigg, J. T. 2006. What Causes ADHD? Understanding what goes wrong and why, New York: The Guildford Press.  [Google Scholar]). This paper examined the performance of children with ADHD-C on interference control and response selection conflict tasks that required both speed and accuracy. The data was analyzed utilizing a new efficiency method to more effectively analyze overall responses. Both interference control and response selection conditions were combined within tasks allowing for a closer comparison of how children with ADHD-C perform on these specific types of cognitive control. Computerized tasks were administered to 62 boys, ages 7 to 12 (31 controls, 31 ADHD-C). Results revealed deficits in efficient performance for children with ADHD-C on interference control tasks and response selection tasks hypothesized to involve high cognitive control demand. These results highlight the utility of analyzing efficiency data to identify deficits in performance for children with ADHD-C and to foster an increased understanding of cognitive control functioning in this clinical population.     

Post-irradiation annealing behaviour of oxide dispersion strengthened Fe-Cr alloys studied by nanoindentation

ABSTRACT

To study the nature of irradiation-induced nanofeatures in oxide dispersion strengthened (ODS) Fe-Cr alloys, post-irradiation isochronal thermal annealing up to 600°C was performed for ODS Fe-9%Cr and Fe-14%Cr alloys ion-irradiated at 300°C and 500°C. Nanoindentation indicated hardening for all as-irradiated alloys and complete hardness recovery upon post-irradiation annealing. Cross-sectional TEM indicated an irradiation-induced defect band near peak damage mainly consisting of dislocation loops. Candidate mechanisms of recovery were critically evaluated. Shrinkage of loops via capture of thermal vacancies was found to correctly reflect the annealing behaviour of ODS Fe-9Cr irradiated at 300°C.     

The Romance of Learning from Disagreement. The Effect of Cohesiveness and Disagreement on Knowledge Sharing Behavior and Individual Performance Within Teams

Purpose  

The purpose of this study was to explore the effects of disagreement and cohesiveness on knowledge sharing in teams, and on the performance of individual team members.     

The Zero programme against bullying: effects of the programme in the context of the Norwegian manifesto against bullying

The anti-bullying programme ‘Zero’ was implemented at 146 Norwegian primary schools. The outcome among pupils was evaluated after 12 months of the total 16-month period using an age-equivalent design. The present study shows that bullying was reduced among pupils in the schools participating in the Zero programme. Moreover, National surveys in spring 2001 and spring 2004 showed a reduction in pupils being victimised in Norway over 3 years. The high profiled national Manifesto Against Bullying started officially in September 2002 and the first period lasted 2 years. The majority of the schools comprising the 2004 national sample reported a substantial increase in anti-bullying work compared to the three-year period before 2001. Interactions between national concern and programme effect are discussed.     

Consolidation and translation regulation

mRNA translation, or protein synthesis, is a major component of the transformation of the genetic code into any cellular activity. This complicated, multistep process is divided into three phases: initiation, elongation, and termination. Initiation is the step at which the ribosome is recruited to the mRNA, and is regarded as the major rate-limiting step in translation, while elongation consists of the elongation of the polypeptide chain; both steps are frequent targets for regulation, which is defined as a change in the rate of translation of an mRNA per unit time. In the normal brain, control of translation is a key mechanism for regulation of memory and synaptic plasticity consolidation, i.e., the off-line processing of acquired information. These regulation processes may differ between different brain structures or neuronal populations. Moreover, dysregulation of translation leads to pathological brain function such as memory impairment. Both normal and abnormal function of the translation machinery is believed to lead to translational up-regulation or down-regulation of a subset of mRNAs. However, the identification of these newly synthesized proteins and determination of the rates of protein synthesis or degradation taking place in different neuronal types and compartments at different time points in the brain demand new proteomic methods and system biology approaches. Here, we discuss in detail the relationship between translation regulation and memory or synaptic plasticity consolidation while focusing on a model of cortical-dependent taste learning task and hippocampal-dependent plasticity. In addition, we describe a novel systems biology perspective to better describe consolidation.     

Motor initiation and execution in patients with conversion paralysis

Motor initiation and motor execution in four patients with conversion paralysis were investigated in a non-affected motor modality (speech). In line with the hypothesis of dissociated control in conversion disorder [Cognit. Neuropsychiatry 8 (1) (2001) 21] motor initiation, but not response duration, was expected to be impaired. The motor initiation times (reaction time: RT) and motor execution times (response duration: RD) were compared on four RT-tasks that required the production of a verbal response: a simple choice RT-task, a mental letter rotation task, and an implicit and an explicit mental hand rotation task. Because conversion disorder is expected to primarily involve an impairment in the initiation of movement, we expected the following task characteristics to uniquely affect RT and not RD: type of instruction (implicit versus explicit instructed imagery), angle of rotation, and target arm (affected versus non-affected arm). The results indeed showed the task characteristics to significantly affect the participants' RT and not their RD. It was concluded that conversion paralysis is associated with a specific impairment in the explicit initiation of processes with a spatial and motor component.     

Implicit sequence learning: effects of level of structure, adult age, and extended practice

The influence of structure and age on sequence learning was investigated by testing 24 young and 24 older participants for 10 sessions in an alternating serial response time task in which pattern trials alternated with random trials. Individuals encountered lag-2 or lag-3 structure, and learning was measured by the difference (in response time and accuracy) between pattern and random trials. Both ages learned lag-2 structure, but the young learned more than the older participants. Only the young people learned lag-3 structure, and they did so more slowly and to a lesser degree than they learned lag-2 structure. These age deficits in higher order sequence learning after extended practice are consistent with simultaneity theory and with theories positing that age-related deficits in neuromodulation lead to less distinctive representations.