1,721,063 research outputs found
Formation and adaptation of memory. Neurobiological mechanisms underlying learning and reversal learning
Full text linkThe hippocampus is a brain region that plays a critical role in memory formation. In addition, it has been suggested that this brain region is important for ‘updating’ information that is incorrect or outdated. The main goal of this thesis project was to investigate which neurobiological processes underlie these processes.
In the majority of the experiments the following method was used: by means of training in a spatial maze, mice learned to visit a specific location to obtain a food reward. After training, the mice were confronted with a modified situation: the food reward was now at a novel location, with no food reward at the previously learned location. To associate the new location with the food reward, mice had to modify the previously formed memory for the original location of the food reward.
We show that within the hippocampus, the protein calcineurin, which has been suggested to suppress the formation of memories, plays a crucial role in modifying previously formed memories. In addition, we reveal that the protein PKA plays a crucial role in the detection of changes in a well-known environment or situation and is involved in the processes required for updating outdated memories.
We also show that sleep loss attenuates the functioning of PKA in the hippocampus. As a result, updating of previously formed memories is delayed. This study gives new insight into the role of sleep in memory processes and shows which proteins play a key role in changing previously stored memories.
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
