Basolateral amygdala noradrenergic activity is involved in the acquisition of conditioned odor aversion in the rat

Conditioned odor aversion (COA) is the avoidance of an odorized-tasteless solution (the conditioned stimulus, CS), the ingestion of which precedes toxicosis. Previous works have shown that the basolateral nucleus of the amygdala (BLA) is involved in the acquisition, and more precisely, the control of the CS memory trace, of COA. Since catecholamine depletion of the amygdala induced a deficit in the potentiated version of COA, this study investigated the role of the adrenergic system in the BLA during COA. Male Wistar rats bilaterally implanted with cannulae aimed at the BLA were microinjected with the beta-adrenergic antagonist propranolol (1 microg/0.2 microl) during the acquisition (5 min before the CS presentation, pre-CS, or immediately after, post-CS) or during the retrieval test (5 min before test, pre-test). Results showed that pre-CS, but neither post-CS nor pre-test, infusions of propranolol impaired COA, suggesting that beta-adrenergic system activity in the BLA is involved in the acquisition but not the expression of COA. Moreover, the fact that pre-CS, but not post-CS, treatment disrupted COA suggests that beta-adrenergic system in the BLA is involved in the initiation but not the maintenance of the CS memory trace during COA acquisition.     

Presence as determined by fractal perceptual-motor dynamics.

This paper presents a tentative model of the role of perceptual-motor dynamics in the emergence of the feeling of presence. A new method allowing the measure of how gaze probes three-dimensional space in immersion is used to support this model. Fractal computations of gaze behavior are shown to be more effective than standard computations of eye movements in predicting presence.     

An Internal Version of Epistemic Logic

Representing an epistemic situation involving several agents obviously depends on the modeling point of view one takes. We start by identifying the types of modeling points of view which are logically possible. We call the one traditionally followed by epistemic logic the perfect external approach, because there the modeler is assumed to be an omniscient and external observer of the epistemic situation. In the rest of the paper we focus on what we call the internal approach, where the modeler is one of the agents involved in the situation. For this approach we propose and axiomatize a logical formalism based on epistemic logic. This leads us to formalize some intuitions about the internal approach and about its connections with the external ones. Finally, we show that our internal logic is decidable and PSPACE-complete.     

Role of cholinergic system on the construction of memories: taste memory encoding

There is a large body of evidence suggesting that cholinergic activity is involved in memory processes. It seems that cholinergic activity is essential to learn several tasks and recent works suggest that acetylcholine plays an important role during the early stages of memory formation. In this review, we will discuss the results related to taste memory formation, focusing particularly on the conditioned taste aversion paradigm. We will first give evidence that nucleus basalis magnocellularis is involved in taste memory formation, due to its cholinergic projections. We then show that the cholinergic activity of the insular (gustatory) cortex is related to the taste novelty, and that the cholinergic signals initiated by novelty are crucial for taste memory formation. Then we present recent data indicating that cortical activation of muscarinic receptors is necessary for taste trace encoding, and also for its consolidation under certain circumstances. Finally, interactions between the cholinergic and other neuromodulatory systems inducing intracellular mechanisms related to plastic changes will be proposed as important processes underlying gustatory memory trace storage.     

Leader–Member Exchange (LMX) and Performance: A Meta‐Analytic Review

This paper reports a meta‐analysis that examines the relationship between leader–member exchange (LMX) relationship quality and a multidimensional model of work performance (task, citizenship, and counterproductive performance). The results show a positive relationship between LMX and task performance (146 samples, ρ = .30) as well as citizenship performance (97 samples, ρ = .34), and negatively with counterproductive performance (19 samples, ρ = ?.24). Of note, there was a positive relationship between LMX and objective task performance (20 samples, ρ = .24). Trust, motivation, empowerment, and job satisfaction mediated the relationship between LMX and task and citizenship performance with trust in the leader having the largest effect. There was no difference due to LMX measurement instrument (e.g., LMX7, LMX‐MDM). Overall, the relationship between LMX and performance was weaker when (a) measures were obtained from a different source or method and (b) LMX was measured by the follower than the leader (with common source‐ and method‐biased effects stronger for leader‐rated LMX quality). Finally, there was evidence for LMX leading to task performance but not for reverse or reciprocal directions of effects.     

Visual Perception Modifies Goal-directed Movement Control: Supporting Evidence from a Visual Perturbation Paradigm

It is well known that dynamic visual information influences movement control, whereas the role played by background visual information is still largely unknown. Evidence coming mainly from eye movement and manual tracking studies indicates that background visual information modifies motion perception and might influence movement control. The goal of the present study was to test this hypothesis. Subjects had to apply pressure on a strain gauge to displace in a single action a cursor shown on a video display and to immobilize it on a target shown on the same display. In some instances, the visual background against which the cursor moved was unexpectedly perturbed in a direction opposite to (Experiment 1), or in the same direction as (Experiment 2) the cursor controlled by the subject. The results of both experiments indicated that the introduction of a visual perturbation significantly affected aiming accuracy. These results suggest that background visual information is used to evaluate the velocity of the aiming cursor, and that this perceived velocity is fed back to the control system, which uses it for on-line corrections.     

Parental Knowledge/Monitoring and Depressive Symptoms During Adolescence: Protective Factor or Spurious Association?

Research on Child and Adolescent Psychopathology - Parental knowledge/monitoring is negatively associated with adolescents’ depressive symptoms, suggesting monitoring could be a target for...     

A cluster analysis of perfectionism among competitive athletes

In the present study, the ways in which athletes may experience perfectionism in a sport context were examined. The question of interest was whether self-confidence, intensity, and direction of cognitive and somatic precompetitive anxiety would differ across identifiable profiles of perfectionism. Competitive athletes (N= 166) completed the Sport-Multidimensional Perfectionism Scale, the French-Canadian Hewitt Multidimensional Perfectionism Scale, and the Competitive State Anxiety Inventory-2 Revised, including a Direction scale. Results of the cluster analysis indicated that athletes could be classified into three groups labelled Nonperfectionists, Adaptive perfectionists, and Maladaptive perfectionists. Perfectionism profiles differed significantly on Cognitive and Somatic Anxiety Intensity and on Cognitive Anxiety Direction. The importance of considering all dimensions of perfectionism simultaneously when examining the functional nature of this construct in sport is discussed.     

The use of event‐related potentials in the study of early cognitive development

The article by Guillaume Thierry is a welcome one, alerting the field to the exciting ways in which event‐related potentials (ERPs) can be used to study cognitive development. It is also timely: there is great interest in the brain sciences, and in how neuroscience can be applied to cognitive development and indeed to education. In my view, however, the article is perhaps too cautious. It does not seem necessary to delay the use of ERPs in cognitive work until all in the field have agreed on the sound characterization of ERP components. It should be possible for further characterization to proceed hand‐in‐hand with data gathering on applied questions. In fact, as partly noted by Thierry, in the auditory domain well‐characterized ERP components are already available, even for infants (e.g. Cheour et al., 1997; Leppänen and Lyytinen, 1997). Furthermore, it is of developmental interest to study older children as well as infants. If ERPs are seen as a tool to complement existing behavioural investigations, rather than as a stand‐alone method to be used independently, then auditory ERPs can certainly be used in current cognitive‐developmental work. Copyright © 2005 John Wiley & Sons, Ltd.