Hyperformulas and Solid Algebraic Systems

Defining a composition operation on sets of formulas one obtains a many-sorted algebra which satisfies the superassociative law and one more identity. This algebra is called the clone of formulas of the given type. The interpretations of formulas on an algebraic system of the same type form a many-sorted algebra with similar properties. The satisfaction of a formula by an algebraic system defines a Galois connection between classes of algebraic systems of the same type and collections of formulas. Hypersubstitutions are mappings sending pairs of operation symbols to pairs of terms of the corresponding arities and relation symbols to formulas of the same arities. Using hypersubstitutions we define hyperformulas. Satisfaction of a hyperformula by an algebraic system defines a second Galois connection between classes of algebraic systems of the same type and collections of formulas. A class of algebraic systems is said to be solid if every formula which is satisfied is also satisfied as a hyperformula. On the basis of these two Galois connections we construct a conjugate pair of additive closure operators and are able to characterize solid classes of algebraic systems. Presented by Wojciech Buszkowski     

Time course and efficiency of protein synthesis inhibition following intracerebral and systemic anisomycin treatment

Since its discovery in the 1960s, anisomycin has been used for studying the impact of protein synthesis for manifold cerebral processes such as long-term plastic changes after learning. The common limitation of nearly all pharmacological experiments, including anisomycin treatment, is to precisely verify the affected brain regions. Here we illustrate anisomycin effects on protein synthesis in distinct brain regions of mice (C57BL/6JOlaHsd), revealing differences between three modes of anisomycin application (subcutaneous, s.c.; intraperitoneal, i.p.; local microinfusions into the hippocampus). Our method is based on inhibition of the incorporation of the radioactively-labelled amino acids [(35)S]-Methionine/Cysteine into newly synthesised proteins. Washing the brain slices before autoradiography removes pools of amino acids, which have not been incorporated into newly synthesised proteins, thus, illustrating pure protein synthesis. By comparing different routes of systemic anisomycin application (i.p. versus s.c.; 150 mg/kg) it became evident that the effect of i.p. injection of anisomycin is fully reversed after 6 h, whereas s.c. injection is inhibiting protein synthesis in the hippocampus even 9 h after application. Local microinfusions of anisomycin into the hippocampus were shown to have long-lasting effects as well, which reversed as late as 9 h after injection. The diffusion of anisomycin was maximal at 3 h after injection and more precisely confined to the intended area using a lower dose (20 microg/site) instead of the commonly used dose of 62.5 microg/site. The broad time window of anisomycin action, as revealed in our study, has to be considered, if it comes to the interpretation of time course studies within the context of protein synthesis-dependent processes.     

High impact running improves learning

Regular physical exercise improves cognitive functions and lowers the risk for age-related cognitive decline. Since little is known about the nature and the timing of the underlying mechanisms, we probed whether exercise also has immediate beneficial effects on cognition. Learning performance was assessed directly after high impact anaerobic sprints, low impact aerobic running, or a period of rest in 27 healthy subjects in a randomized cross-over design. Dependent variables comprised learning speed as well as immediate (1 week) and long-term (>8 months) overall success in acquiring a novel vocabulary. Peripheral levels of brain-derived neurotrophic factor (BDNF) and catecholamines (dopamine, epinephrine, norepinephrine) were assessed prior to and after the interventions as well as after learning. We found that vocabulary learning was 20 percent faster after intense physical exercise as compared to the other two conditions. This condition also elicited the strongest increases in BDNF and catecholamine levels. More sustained BDNF levels during learning after intense exercise were related to better short-term learning success, whereas absolute dopamine and epinephrine levels were related to better intermediate (dopamine) and long-term (epinephrine) retentions of the novel vocabulary. Thus, BDNF and two of the catecholamines seem to be mediators by which physical exercise improves learning.