Browsing by Subject "anchoring"

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  • Moliner, Rafael (Helsingin yliopisto, 2019)
    Classical and rapid-acting antidepressant drugs have been shown to reinstate juvenile-like plasticity in the adult brain, allowing mature neuronal networks to rewire in an environmentally-driven/activity-dependent process. Indeed, antidepressant drugs gradually increase expression of brain-derived neurotrophic factor (BDNF) and can rapidly activate signaling of its high-affinity receptor TRKB. However, the exact mechanism of action underlying drug-induced restoration of juvenile-like plasticity remains poorly understood. In this study we first characterized acute effects of classical and rapid-acting antidepressant drugs on the interaction between TRKB and postsynaptic density (PSD) proteins PSD-93 and PSD-95 in vitro. PSD proteins constitute the core of synaptic complexes by anchoring receptors, ion channels, adhesion proteins and various signaling molecules, and are also involved in protein transport and cell surface localization. PSD proteins have in common their role as key regulators of synaptic structure and function, although PSD-93 and PSD-95 are associated with different functions during development and have opposing effects on the state of plasticity in individual synapses and neurons. Secondly, we investigated changes in mobility of TRKB in dendritic structures in response to treatment with antidepressant drugs in vitro. We found that antidepressant drugs decrease anchoring of TRKB with PSD-93 and PSD-95, and can rapidly increase TRKB turnover in dendritic spines. Our results contribute to the mechanistic model explaining drug-induced restoration of juvenile-like neuronal plasticity, and may provide a common basis for the effects of antidepressant drugs.
  • Leppämäki, Sanna-Kaisa (2006)
    In contemporary western societies people face a wide range of different foods and information about them. What happens when a person concretely encounters foods that are unfamiliar to them? Food encounter is a complex interplay between the food and the individual in a given context involving biological, psychological, social and cultural aspects. The theory of social representations offers a perspective to study this interplay. The objective of this work was to study the process of anchoring, described by the theory, of representations related to new foods. The method was based on the observation of the subjects' actions in concrete, experimental food encounter situations. Filming and debrief interviews were used to capture the phenomena in these encounters. Filming was done with two cameras, one giving an overall view, and a miniature camera (subcam) carried by the subject, giving his visual perspective to the situation. Analysis of the film material gave detailed empirical evidence of the anchoring process of which mechanisms are not specified by the theory. In making sense of the foods, the subjects engaged in explorative actions in relation to the foods, the other person and their own prior representations. Already existing representations influenced both actions and conclusions concerning the foods: These results support the theory's view of anchoring as classification in terms of the already known categories of thought. By actions directed to the researcher, i.e. verbal and non-verbal social probing, representational elements were actively sought from the other person. Introducing the same food as organic or genetically modified did in several cases influence the sample exploration, and through it also the sensory perceptions and the interpretation about them - these findings also indicated that anchoring could operate in a way of self-fulfilling prophecy. Moreover, the subjects organized their actions according to their interpretations about the demands of the research situation. The results show that anchoring is not limited to cognitive aspects, and points the importance of social interaction in this process, and opens new perspectives for the theory and practice in the domain of new products adoption.