The complexity of satisfiability for fragments of hybrid logic—Part I

The satisfiability problem of hybrid logics with the downarrow binder is known to be undecidable. This initiated a research program on decidable and tractable fragments.In this paper, we investigate the effect of restricting the propositional part of the language on decidability and on the complexity of the satisfiability problem over arbitrary, transitive, total frames, and frames based on equivalence relations. We also consider different sets of modal and hybrid operators. We trace the border of decidability and give the precise complexity of most fragments, in particular for all fragments including negation. For the monotone fragments, we are able to distinguish the easy from the hard cases, depending on the allowed set of operators.     

Multiple family therapy for anorexia nervosa: concepts, experiences and results

Multiple family therapy (MFT) is an increasingly popular treatment approach for adolescents suffering from anorexia nervosa and their families. This paper describes the ingredients and different phases of this treatment, and outlines its indications and contra‐indications. Relationship patterns in families containing anorectic teenagers are examined, with a special emphasis on identifying areas for change in family relationships. Results with regard to the overall acceptability of the approach are presented.     

Emotional and learning behaviour in mice overexpressing heat shock protein 70

The effects of inducible heat shock protein 70 (HSP70) on emotional and learning behaviour as well as hippocampal long-term potentiation was investigated in transgenic HSP70 overexpressing mice. In active two-way avoidance learning (shuttle box) as well as spatial 8-arm radial maze learning, the HSP70 overexpressing mice showed diminished learning performance. In several tests there was no indication of differences in anxiety behaviour between transgenic mice and wild-type mice. This suggests that impairment in learning behaviour is unrelated to the learning task and motivational aspects of behaviour. To investigate the neurophysiological correlate of learning, long-term potentiation experiments were performed. In transversal hippocampal slices, an enhanced amplitude of the population spike was found in HSP70 overexpressing mice. It was hypothesised that enhanced potentiation in conjunction with potentiation effects due to learning led to learning impairment.     

Gruppenpsychotherapie Die unbekannte und benachteiligte psychotherapeutische Behandlungsoption

Gruppenbehandlungen stellen die angemessene Indikation für ein sehr breites Spektrum von psychischen Störungsbildern und somatischen Erkrankungen dar. Für einige psychische Störungen, wie Persönlichkeitsstörungen, psychiatrische Erkrankungen, Essstörungen, Substanzmissbrauch, psychosomatische Erkrankungen und funktionelle Störungsbilder sowie chronische körperliche Erkrankungen, ist die Gruppenbehandlung sogar die beste indikative Option. Das mögliche breite Behandlungsspektrum ist weithin unbekannt. Hinzu treten hierzulande administrative Behinderungen, die speziell im ambulanten Versorgungsbereich die Gruppenbehandlung gegenüber der einzeltherapeutischen Behandlung benachteiligen, so dass die angemessenere und kostengünstigere Option einer Gruppenbehandlung hier viel zu wenig zum Tragen kommt.     

Zur Bedeutung von Gruppenleitern in der gruppenpsychotherapeutischen Weiterbildung

Training in group therapy is fundamentally based on self-experience in groups. The importance of the model character of the group leader's role has hardly been subject to empirical research in spite of its highly qualified and specialized requirements. In order to ensure process quality in group therapy training, the effects of the leader's model on the reported learning effects of 413 members in 35 short-term Process (self-awareness) and so-called Special Interest (thematically focused) groups of the American Group Psychotherapy Association (AGPA) were investigated. The first two sessions out of four were investigated by process questionnaires focusing on self-experience, experience of the group atmosphere and subjective impressions of the group leaders' performances. These process variables were later correlated with the overall learning impression after all four sessions. It turned out that particularly those group leaders' styles and attitudes had a strong positive correlation with favourable learning effects, that were decisive and charismatic instead of vague and that group leaders who were experienced by group members as predominantly indecisive, vague and less charismatic were in spite of the fact of being seen as competent and skillful produced weak learning effects. Results are discussed in the light of the need of neophyte group therapists to identify with a leader model promising to provide authority and sovereignity even prior to competence and empathy given the anticipatory fear regarding possible critical group dynamics in future therapy groups.     

Genetic inactivation of D-amino acid oxidase enhances extinction and reversal learning in mice

Activation of the N-methyl-d-aspartate receptor (NMDAR) glycine site has been shown to accelerate adaptive forms of learning that may benefit psychopathologies involving cognitive and perseverative disturbances. In this study, the effects of increasing the brain levels of the endogenous NMDAR glycine site agonist D-serine, through the genetic inactivation of its catabolic enzyme D-amino acid oxidase (DAO), were examined in behavioral tests of learning and memory. In the Morris water maze task (MWM), mice carrying the hypofunctional Dao1^G181R mutation demonstrated normal acquisition of a single platform location but had substantially improved memory for a new target location in the subsequent reversal phase. Furthermore, Dao1^G181R mutant animals exhibited an increased rate of extinction in the MWM that was similarly observed following pharmacological administration of D-serine (600 mg/kg) in wild-type C57BL/6J mice. In contextual and cued fear conditioning, no alterations were found in initial associative memory recall; however, extinction of the contextual fear memory was facilitated in mutant animals. Thus, an augmented level of D-serine resulting from reduced DAO activity promotes adaptive learning in response to changing conditions. The NMDAR glycine site and DAO may be promising therapeutic targets to improve cognitive flexibility and inhibitory learning in psychiatric disorders such as schizophrenia and anxiety syndromes.The N-methyl-d-aspartate receptor (NMDAR) has an important role in excitatory neurotransmission and contributes to numerous brain processes, including synaptic plasticity, learning, and memory formation (Nicoll 2003). Activation of NMDARs requires membrane depolarization in addition to concurrent binding of glutamate to NMDAR2 (NR2) and glycine to the NMDAR1 (NR1) subunit (Johnson and Ascher 1987; Clements and Westbrook 1991). D-serine has also been shown to be an endogenous co-agonist for the NR1 glycine site, acting with high selectivity and a potency similar to or greater than that of glycine (Matsui et al. 1995). In the brain, the localization of D-serine closely resembles that of NMDARs (Schell et al. 1997), and D-serine has been reported to be the predominant physiologic co-agonist for the maintenance of NMDAR-mediated currents in the hippocampus, retina, and hypothalamus (Mothet et al. 2000; Yang et al. 2003). Moreover, in vivo studies have demonstrated that the NMDAR glycine site is not saturated at the synapses of several brain regions (Fuchs et al. 2005). Consequently, increasing D-serine levels may modulate neurotransmission and behavioral responses reliant on NMDAR activity.The NMDAR glycine site has been implicated in the pathophysiology and treatment of a number of psychiatric conditions (Coyle and Tsai 2004; Millan 2005). Blockade of the NMDAR with noncompetitive antagonists like phencyclidine results in the production and exacerbation of schizophrenic-like symptoms in humans and animals (Javitt and Zukin 1991; Krystal et al. 1994). Genetic studies have associated genes that mediate D-serine synthesis and degradation with a vulnerability to schizophrenia, and levels of D-serine are decreased in the CSF and serum of schizophrenic patients (Chumakov et al. 2002; Hashimoto et al. 2003, 2005; Schumacher et al. 2004; Morita et al. 2007). These observations prompted clinical trials with direct and indirect activators of the NMDAR glycine site, including D-serine, and improvements were revealed when these compounds were added to conventional antipsychotic regimes, particularly with the negative and cognitive symptoms of schizophrenia (Tsai et al. 1998; Coyle and Tsai 2004; Heresco-Levy et al. 2005). Furthermore, altered NMDAR activation has also been shown to affect extinction, a learning process that may be of benefit in anxiety illnesses, such as post-traumatic stress syndrome and obsessive-compulsive disorder (Davis et al. 2006). In rodents, extinction was shown to be impaired following inhibition of NMDARs in contextual fear conditioning, inhibitory avoidance, and eyeblink conditioning tasks (Kehoe et al. 1996; Lee and Kim 1998; Szapiro et al. 2003). In contrast, the partial NMDAR agonist D-cycloserine facilitated the extinction of fear memories in rodents and individuals with phobias and other anxiety disorders (Ressler et al. 2004; Ledgerwood et al. 2005; Norberg et al. 2008). Thus, the NMDAR glycine site and its related modulatory proteins may be important targets for the amelioration of psychopathologies involving cognitive dysfunction and maladaptive behaviors.Endogenous levels of D-serine in the brain are regulated by its catabolic enzyme, D-amino acid oxidase (DAO); by the D-serine synthesis enzyme, serine racemase (Srr); and by neuronal and glial transporters (Foltyn et al. 2005; Martineau et al. 2006). Agents targeting such proteins may prove to be an effective method of increasing cerebral D-serine and occupancy of the NMDAR glycine site, which could overcome the difficulties D-serine and similar compounds have with penetrating the blood-brain barrier (Coyle and Tsai 2004; Bauer et al. 2005). Inhibiting DAO function in the brain is of particular interest as it would circumvent any nephrotoxicity associated with high levels of systemic D-serine (Maekawa et al. 2005a). DAO is a peroxisomal flavoprotein that at physiological pH is highly selective for D-serine, and in the brain, DAO is located predominantly in astrocytes (Mothet et al. 2000). An inverse correlation between the brain distribution of DAO and D-serine evinces the efficacy of this enzyme, with the most abundant DAO expression located in the D-serine-sparse hindbrain and cerebellum (Schell et al. 1995; Moreno et al. 1999). To study the effects of limiting DAO function, we tested a line of mice carrying a single point mutation (G181R) that results in a complete lack of DAO activity and consequently augmented D-serine in serum and brain (Sasaki et al. 1992; Hashimoto et al. 1993). These mice have previously been shown to exhibit an in vitro increase in NMDAR-mediated excitatory postsynaptic currents in dorsal horn neurons of the spinal cord and an in vivo elevation of cGMP that is indicative of augmented NMDAR activity (Wake et al. 2001; Almond et al. 2006). This demonstrates that reduced DAO function is capable of augmenting NMDAR activation, and it may follow that cognitive and extinction processes influenced by NMDARs are enhanced in Dao1^G181R mutant mice. To investigate this possibility, we assessed the effects of the Dao1^G181R mutation on learning, memory, and extinction in Morris water maze (MWM) and in contextual and cued fear conditioning paradigms.     

The judgement of behaviour as aggressive and sanctionable

The influence of the factors norm deviation, intent, and injury, on the judgement of a critical act as aggressive and sanctionable was tested using a 2 × 2 × 2 factorial design. Scenarios depicting aggressive interactions represented the experimental conditions. 859 school children rated these scenarios on bipolar rating scales. The results show that norm deviation, intent, and injury, are important criteria for the interpretation of aggressive behaviour. Judging an action as sanctionable proved to be more sensitive for the variation of factors than the interpretation of behaviour as aggressive. In addition, an analysis of how the scenarios representing the experimental conditions were subjectively interpreted by the subjects was carried out. This showed that all combinations of the three definition criteria are psychologically meaningful. However, preferences were observed for specific interpretation patterns.     

The perception of identity by 6 1/2-month-old infants.

In Study 1, sixteen 6 1/2-month-olds were habituated to a Reversible stimulus (an upright face that could be perceived as an entirely different upright face when it was rotated 180 degrees) and to a Nonreversible stimulus (a face that could be perceived as upright in only one orientation). Following habituation for each type of stimulus, test trials paired the habituated face with a novel stimulus (an inversion of the same face). For both Reversible and Nonreversible stimuli, the physical difference between the old and new test stimuli was the same (a 180 degrees rotation); however, infants devoted more visual attention to the 180 degrees rotation only when it was a Reversible face, suggesting that the identity change was detected. Experiment 2 ruled out the explanation that infants might have failed to dishabituate to the inversion of the Nonreversible stimulus because they could not remember it. Results are interpreted as evidence that 6 1/2-month-old infants are not limited to face recognition based on similarity in pattern arrangement alone, but are capable of processing faces at a representational level.     

Semantic relations between encoding and retrieval in cued recall

Two experiments were conducted to test the encoding-specificity hypothesis. In Experiment 1, subjects were presented pairs of coordinates to study, followed by a cued-recall test. Semantically weak and strong coordinates (defined by the degree of featural overlap shared with the pairs) served as encoding and retrieval cues. The semantic strength of the retrieval cue proved to be the most important factor in recall, whereas the re-presentation of an unrelated cue previously seen during encoding led to no facilitation of recall. In Experiment 2, three noun coordinates of varied semantic interrelatedness were presented for study and then were cued for recall by novel semantically strong or weak coordinates. Maximum recall was achieved when a strong encoding condition was matched with a strong retrieval cue. Implications of these findings for an encoding-specificity hypothesis were discussed.