Effect of stress induced by electrical stimulation of the hypothalamus on the electrical stability of the heart in rabbits

The influence of stress on cardiac electrical stability (CES) and chaotic dynamics of the electrical activity of the heart was studied in acute and chronic experiments in rabbits. Stress was caused by 2-3 h daily immobilization of the animals with electrical stimulation of emotiogenic centers of the hypothalamus through implanted electrodes. CES was estimated by the thresholds for ventricular arrhythmia: paroxysmal ventricular tachycardia, repeated ventricular extrasystoles and ventricular fibrillation (VF). The results showed: (i) CES in stressed rabbits was decreased significantly compared with controls; (ii) the level of chaos at the onset of VF in stressed rabbits was increased significantly compared with controls; (iii) heart rate of stressed rabbits was significantly greater than in controls; (iv) changes in CES parameters depended on whether stress was acute or chronic; (v) acute stress promoted transition of spontaneously reversible VF into spontaneously irreversible VF. Thus, stress increased the degree of disorganization of heart electrical activity and also decreased its electrical stability. The experiments indicate that stress is a destabilizing factor influencing the reversibility of heart rate disorders. The probability of such reversibility depends on whether stress is acute or chronic: acute stress is more likely to lead to irreversible spontaneous VF.     

Effects of NMDA receptor channel blockade on aggression in isolated male mice

N‐Methyl‐D ‐aspartate (NMDA) receptor antagonists are perspective candidates for medication development for a number of diseases/states that are associated with increased aggressiveness (e.g., opioid withdrawal). The prototypic NMDA receptor antagonist phencyclidine (PCP) itself is a widely abused substance and is known to elevate levels of aggression in drug users. The present study was aimed at testing several drugs that share with PCP the ability to block NMDA receptor–associated channel. The resident‐intruder procedure was used to assess drug effects on aggressive behavior in isolated male mice. Resident aggressive mice were administered NMDA channel blockers (PCP; 0.3–10 mg/kg), dizocilpine (MK‐801; 0.01–0.3 mg/kg), memantine (1–30 mg/kg), and MRZ 2/579 (0.1–5.6 mg/kg). The competitive NMDA receptor antagonist D CPPene (0.1–5.6 mg/kg) was also tested as a compound representing an alternative approach to reduce activity of NMDA receptor complex. PCP, dizocilpine, and memantine inhibited expression of aggressive behaviors only at doses that produced ataxia. The novel channel blocker MRZ 2/579 also produced ataxia at the highest dose level but failed to affect aggressiveness. Reduction in aggression with a corresponding increase in sociability was observed after administration of D ‐CPPene. Overall, the present results suggest that NMDA receptor channel blockers do not exert selective effects on aggressive behavior. Aggr. Behav. 25:381–396, 1999. © 1999 Wiley‐Liss, Inc.     

Parents' child‐rearing values and beliefs in the United States and Russia: the impact of culture and social class

Parents' values for their children and their beliefs about appropriate child‐rearing practices contribute to the ways in which they try to shape their children's development. This paper examines the values and beliefs of 71 parents (37 mothers and 34 fathers) from two cities in the United States and Russia. Half of the families were middle class (determined by education and occupation criteria) and half were working class. The results revealed no cross‐societal differences in value for self‐direction in the children; perhaps reflecting the recent economic and ideological changes in Russia. In contrast, significant social class differences, for both mothers and fathers, were found in child‐rearing values and beliefs. Middle class parents in both societies were more likely to value self‐direction and believe that children should have freedom in and around the home, whereas working class parents were more likely to believe that children should be expected to conform to rules. The results of this study underscore the role of within‐society heterogeneity, as a function of social class, in parents' values and beliefs about child‐rearing.     

A psychophysiological study of auditory illusions of approach and withdrawal in the context of the perceptual environment

Auditory perception of the depth of space is based mainly on spectral and amplitude changes of sound waves originating from the sound source and reaching the listener. The perceptive illusion of movement of an auditory image caused by changes in amplitude and/or frequency of the signal tone emanating from an immobile loudspeaker was studied. Analysis of data obtained from the participants revealed the diapason of combinations of amplitude and frequency changes for which the movement direction was perceived similarly by all participants, despite significantly different movement assessment criteria. Additional auditory and visual information of the conditions of radial movement (near or far fields) determined listeners' interpretation of changes in the signal parameters. The data obtained about the perception of approach and withdrawal models are evidence of the fact that the principal cues of the perception of the distance of immobile sound sources manifests similarly to that of an auditory image moving along a radial axis.     

Regression I. Experimental approaches to regression

The concept of regression is considered with an emphasis on the differences between the positions of Freud and Jung regarding its significance. The paper discusses the results of experimental analyses of individual experience dynamics (from gene expression changes and impulse neuronal activity in animals to prosocial behaviour in healthy humans at different ages, and humans in chronic pain) in those situations where regression occurs: stress, disease, learning, highly emotional states and alcohol intoxication. Common mechanisms of regression in all these situations are proposed. The mechanisms of regression can be described as reversible dedifferentiation, which is understood as a relative increase of the representation of low-differentiated (older) systems in the actualized experience. In all of the cases of dedifferentiation mentioned above, the complexity of the systemic organization of behaviour significantly decreases.     

Quantum-like generalization of the Bayesian updating scheme for objective and subjective mental uncertainties

In this paper we develop a general quantum-like model of decision making. Here updating of probability is based on linear algebra, the von Neumann–Lüders projection postulate, Born’s rule, and the quantum representation of the state space of a composite system by the tensor product. This quantum-like model generalizes the classical Bayesian inference in a natural way. In our approach the latter appears as a special case corresponding to the absence of relative phases in the mental state. By taking into account a possibility of the existence of correlations which are encoded in relative phases we developed a more general scheme of decision making. We discuss natural situations inducing deviations from the classical Bayesian scheme in the process of decision making by cognitive systems: in situations that can be characterized as objective and subjective mental uncertainties. Further, we discuss the problem of base rate fallacy. In our formalism, these “irrational” (non-Bayesian) inferences are represented by quantum-like bias operations acting on the mental state.     

The self regulatory effect of attentional control in modulating the relationship between attentional biases toward threat and anxiety symptoms in children

The present study examined the associations between attentional biases to threat, attentional control and anxiety in a sample of children aged 9 to 14. It was hypothesised that the association between attentional biases toward threat and anxiety might be stronger when the ability to control attention is reduced. The study employed pictures of neutral, happy and angry facial expressions as they have greater ecological value compared to words. Children completed a dot-probe task measuring attentional biases toward such stimuli. They also completed the Spence child anxiety scale for anxiety symptoms and, for attentional control, the child version of the attention control scale measuring the ability to focus and shift attention. Results of a hierarchical regression analysis showed that attentional control significantly explained anxiety. Furthermore, the interaction between attentional control and attentional biases significantly explained anxiety level. These results indicate that attentional control moderates the relation between attentional biases toward threatening facial expressions and anxiety in children. Additionally, a discussion about a possible protective role of attentional control is provided.     

An Inkblot for the Implicit Assessment of Personality: The Semantic Misattribution Procedure

Misattributions people make about their own reaction to ambiguous stimuli can be used to measure personality self‐concepts implicitly. On the basis of a semantic misattribution priming paradigm [semantic misattribution procedure (SMP)], we assessed the implicit personality self‐concept related to three dimensions included in the Big‐Five model: conscientiousness, neuroticism, and extraversion. Across three studies (N1 = 98, N2 = 140, and N3 = 135), the SMP was robustly related, in the expected direction, to individual differences in self‐reported personality questionnaires and managed to predict both self‐reported and objectively measured behaviours. The main advantage of SMP over classical explicit measures of personality is its higher resistance to social desirability tendencies, although its psychometric properties are somewhat lower than those pertaining to explicit measures of personality. Finally, comparisons of our results with studies that used other implicit measures of personality self‐concept indicate that the SMP has higher criterion validity. Copyright © 2012 John Wiley & Sons, Ltd.     

Are preventive and generative causal reasoning symmetrical? Extinction and competition

We tested whether preventive and generative reasoning processes are symmetrical by keeping the training and testing of preventive (inhibitory) and generative (excitatory) causal cues as similar as possible. In Experiment 1, we extinguished excitors and inhibitors in a blocking design, in which each extinguished cause was presented in compound with a novel cause, with the same outcome occurring following the compound and following the novel cause alone. With this novel extinction procedure, the inhibitory cues seemed more likely to lose their properties than the excitatory cues. In Experiment 2, we investigated blocking of excitatory and inhibitory causes and found similar blocking effects. Taken together, these results suggest that acquisition of excitation and inhibition is similar, but that inhibition is more liable to extinguish with our extinction procedure. In addition, we used a variable outcome, and this enabled us to test the predictions of an inferential reasoning account about what happens when the outcome level is at its minimum or maximum (De Houwer, Beckers, & Glautier, 2002). We discuss the predictions of this inferential account, Rescorla and Wagner's (1972) model, and a connectionist model-the auto-associator.     

Contracting,equal, and expanding learning schedules: The optimal distribution of learning sessions depends on retention interval

In laboratory and applied learning experiments, researchers have extensively investigated the optimal distribution of two learning sessions (i.e., initial learning and one relearning session) for the learning of verbatim materials. However, research has not yet provided a satisfying and conclusive answer to the optimal scheduling of three learning sessions (i.e., initial learning and two relearning sessions) across educationally relevant time intervals. Should the to-be-learned material be repeated at decreasing intervals (contracting schedule), constant intervals (equal schedule), or increasing intervals (expanding schedule) between learning sessions? Different theories and memory models (e.g., study-phase retrieval theory, contextual variability theory, ACT-R, and the Multiscale Context Model) make distinct predictions about the optimal learning schedule. We discuss the extant theories and derive clear predictions from each of them. To test these predictions empirically, we conducted an experiment in which participants studied and restudied paired associates with a contracting, equal, or expanding learning schedule. Memory performance was assessed immediately, 1 day, 7 days, or 35 days later with free- and cued-recall tests. Our results revealed that the optimal learning schedule is conditional on the length of the retention interval: A contracting learning schedule was beneficial for retention intervals up to 7 days, but both equal and expanding learning schedules were better for a long retention interval of 35 days. Our findings can be accommodated best by the contextual variability theory and indicate that revisions are needed to existing memory models. Our results are practically relevant, and their implications for real-world learning are discussed.