Olfactory traces and spatial learning in rats.

We conducted an experiment to assess the use of olfactory traces for spatial orientation in an open environment in rats, Rattus norvegicus. We trained rats to locate a food source at a fixed location from different starting points, in the presence or absence of visual information. A single food source was hidden in an array of 19 petri dishes regularly arranged in an open-field arena. Rats were trained to locate the food source either in white light (with full access to distant visuospatial information) or in darkness (without any visual information). In both cases, the goal was in a fixed location relative to the spatial frame of reference. The results of this experiment revealed that the presence of noncontrolled olfactory traces coherent with the spatial frame of reference enables rats to locate a unique position as accurately in darkness as with full access to visuospatial information. We hypothesize that the olfactory traces complement the use of other orientation mechanisms, such as path integration or the reliance on visuospatial information. This experiment demonstrates that rats can rely on olfactory traces for accurate orientation, and raises questions about the establishment of such traces in the absence of any other orientation mechanism. Copyright 1998 The Association for the Study of Animal Behaviour.

Family relationships and learning experiences in anxious vs. non-anxious families: Are there differences ?

L'objectif principal de ce travail était d'explorer les relations parent-enfant et les processus d'apprentissage familiaux associés aux troubles anxieux. A cet effet, des familles ayant un membre anxieux (la mère ou l'enfant) ont été comparées avec des familles n'ayant aucun membre anxieux. Dans une première étude, l'observation de l'interaction mère-enfant, pendant une situation standardisée de jeu, a révélé que les mères présentant un trouble panique étaient plus susceptibles de se montrer verbalement contrôlantes, critiques et moins sensibles aux besoins de l'enfant, que les mères qui ne présentaient pas de trouble panique. Une deuxième étude a examiné les perceptions des différents membres de la famille quant aux relations au sein de la famille et a indiqué que, par comparaison aux adolescents non-anxieux, les adolescents anxieux étaient plus enclins à éprouver un sentiment d'autonomie individuelle diminué par rapport à leurs parents. Finalement, une troisième étude s'est intéressée à déterminer l'impact d'expériences d'apprentissage moins directes dans l'étiologie de l'anxiété. Les résultats ont indiqué que les mères présentant un trouble panique étaient plus enclines à s'engager dans des comportements qui maintiennent la panique et à impliquer leurs enfants dans ces comportements, que les mères ne présentant pas de trouble panique. En se basant sur des recherches antérieures qui ont établi une relation entre le contrôle parental, la perception de contrôle chez l'enfant et les troubles anxieux, le présent travail non seulement confirme ce lien mais propose également un modèle pour résumer l'état actuel des connaissances concernant les processus familiaux et le développement des troubles anxieux. Deux routes ont été suggérées par lesquelles l'anxiété pourrait être transmise de manière intergénérationnelle. Chacune de ces routes attribue un rôle important à la perception de contrôle chez l'enfant. L'idée est que lorsque les enfants présentent une prédisposition à interpréter le comportement de leurs parents comme hors de leur contrôle, ils seraient plus enclins à développer de l'anxiété. A ce titre, la perception du contrôle représenterait un tampon entre le comportement de contrôle/surprotection des parents et le trouble anxieux chez l'enfant. - The principal objective of the present work was to explore parent-child relationships and family learning processes associated with anxiety disorders. To this purpose, families with and without an anxious family member (mother or child) were compared. In a first study, observation of mother-child interaction, during a standard play situation, revealed that mothers with panic disorder were more likely to display verbal control and criticism, and less likely to display sensitivity toward their children than mothers without panic disorder. A second study examined family members' perceptions of family relationships and indicated that compared to non-anxious adolescents, anxious adolescents were more prone to experience a diminished sense of individual autonomy in relation to their parents. Finally a third study was interested in determining the effect of less direct learning experiences in the aetiology of anxiety. Results indicated that mothers with panic disorder were more likely to engage in panic-maintaining behaviour and to involve their children in this behaviour than mothers without panic disorder. Based on previous research showing a relationship between parental control, children's perception of control, and anxiety disorders, the present work not only further adds evidence to support this link but also proposes a model summarizing the current knowledge concerning family processes and the development of anxiety disorders. Two pathways have been suggested through which anxiety may be intergenerationally transmitted. Both pathways assign an important role to children's perception of control. The idea is that whenever children have a predisposition towards interpreting their parents' behaviour as beyond of their control, they may be more prone to develop anxiety. As such, perceived control may represent a buffer between parental overcontrolling/overprotective behaviours and childhood anxiety disorder.

A behavioral study of alpha-1b adrenergic receptor knockout mice: increased reaction to novelty and selectively reduced learning capacities.

Knockout mice lacking the alpha-1b adrenergic receptor were tested in behavioral experiments. Reaction to novelty was first assessed in a simple test in which the time taken by the knockout mice and their littermate controls to enter a second compartment was compared. Then the mice were tested in an open field to which unknown objects were subsequently added. Special novelty was introduced by moving one of the familiar objects to another location in the open field. Spatial behavior and memory were further studied in a homing board test, and in the water maze. The alpha-1b knockout mice showed an enhanced reactivity to new situations. They were faster to enter the new environment, covered longer paths in the open field, and spent more time exploring the new objects. They reacted like controls to modification inducing spatial novelty. In the homing board test, both the knockout mice and the control mice seemed to use a combination of distant visual and proximal olfactory cues, showing place preference only if the two types of cues were redundant. In the water maze the alpha-1b knockout mice were unable to learn the task, which was confirmed in a probe trial without platform. They were perfectly able, however, to escape in a visible platform procedure. These results confirm previous findings showing that the noradrenergic pathway is important for the modulation of behaviors such as reaction to novelty and exploration, and suggest that this is mediated, at least partly, through the alpha-1b adrenergic receptors. The lack of alpha-1b adrenergic receptors in spatial orientation does not seem important in cue-rich tasks but may interfere with orientation in situations providing distant cues only.