No description available.

No description available.

Ecological context, sensory inputs, and the internal physiological state are integrated for an animal to make appropriate behavioral decisions. However, these factors have rarely been studied in the same system. In the African cichlid fish Astatotilapia burtoni, males alternate between four phenotypes. Two are determined by social status and two are identified by the principle body coloration (yellow or blue). When socially dominant (DOM), fish display bright body coloration and a wealth of aggressive and reproductive behaviors. Subordinate (SUB) males decrease predation risk by adopting cryptic coloration and schooling behavior. Yellow males are more conspicuous than blue males, and DOMs and more conspicuous than SUBs, which means that yellow DOMs are most likely to be seen by predators. We therefore hypothesized that DOMs, yellow DOMs in particular, would show enhanced startle-escape responsiveness to compensate for their increased predation risk. Indeed, behavioral responses to sound clicks of various intensities showed a significantly higher mean startle rate in DOMs than SUBs. When testing the same males after social change, yellow DOMs respond at a higher rate than yellow SUBs but blue males do not show plasticity. Electrophysiological recordings from the Mauthner cells (Mcells), the neurons triggering startle, were performed in anesthetized animals and showed larger synaptic responses to sound clicks in DOMs, consistent with the behavioral results. In addition, the inhibitory drive mediated by interneurons presynaptic to the M-cell was significantly reduced in DOMs. Using behavioral tests, intracellular recordings, and single-cell molecular analysis, immunohistochemistry and in-situ hybridization, I show here that serotonin modulates this socially regulated plasticity via the 5-HT receptor subtype 2 (HTR2A). Specifically, SUBs display increased sensitivity to pharmacological blockade of HTR2A compared with DOMs in both startle-escape behavior and electrophysiological properties of the M-cell. These receptors, however, are not expressed in the Mauthner neurons, but in the inhibitory interneurons that regulate the Mcell’s membrane properties. I show a role for 5-HT in modulating startle plasticity and increase our understanding of the neural basis of behavioral plasticity. More broadly, this study provides an integrative explanation of an ecological and social trade-off at the level of an identifiable decision-making neural circuit. / text

No description available.

Glutamate AMPA receptors (AMPARs) are major excitatory receptors in the vertebrate CNS. In many biological systems there are changes in the properties of AMPARs during development that are essential for providing an increase in efficiency of information transfer between neurons and a refinement of motor co-ordination and sensory perception and cognition. It is not surprising that improper development or loss of function of AMPARs can lead to many neurological disorders such as epilepsy and amyotrophic lateral sclerosis. Thus, determining the mechanisms by which AMPARs mature is of particular importance. The objectives of my thesis were to characterize the developmental changes in AMPAR-mediated currents in zebrafish Mauthner cells and to determine the mechanisms underlying any changes. The major findings reported in this thesis are that (1) there are developmental changes in the properties of AMPAR-currents as the Mauthner cell matures; (2) the mechanism underlying these changes is a switch in the composition of AMPA receptor subtypes; and (3) PKC is necessary for the developmental switch in AMPAR subtypes from slow receptors to fast receptors. These findings provide valuable insights into the mechanism underlying the development of AMPARs. In addition, they provide the first instance of a signalling link (PKC) required for the developmental subunit switch and the developmental speeding of AMPAR kinetics. / Physiology, Cell Biology and Developmental Biology

Thesis (Ph. D.)--University of Chicago, Department of Germanic Studies, August 2002. / Includes bibliographical references. Also available on the Internet.

Beginning with the 80-s of the 19th century, literature starts to increasingly take language as a problem. First of all, claims of the language for reflecting the truth are questioned, and, consequently, it is revaluated as an instrument of cognition (mostly, negatively). Very often texts, related to a language conundrum, may contain either anti-religions argumentation, or an active use of imagery, tinged with religion, or Biblical symbology. In this work, the interrelation between religiousness, reflected in the text, and its approach to the problematics of the language are investigated. In the shadow of the crisis of the language of literature modernism, such topics as the process of language secularization, language origin, and the crisis of cognition and of a person have also been touched upon. As exemplified by F. Mauthner, W. Benjamin, H. Hofmannsthal и C. Mierendorff, different concepts of the language and ways out of the crisis, offered by them, are presented. Also, their way to interact with religiousness and and mysticism was taken into account. In the result of the research, a certain tendency has been tapped: in case when a language is approached as an instrument that has no relation to mysticism, it shows its incapacity as an instrument of cognition (Mauthner). If a language is viewed...

Les neurones sensorials projecten al sistema nerviós central seguint una distribució espacial ordenada, formant mapes neuronals que representen propietats dels estímuls sensorials i que són considerats essencials per a la interpretació del món extern. He utilitzat la línia lateral de la larva del peix zebra com a model per a l’estudi de l’organització i el desenvolupament dels mapes neuronals sensorials. Les neurones sensorials de la línia lateral formen un mapa neuronal topogràfic, anomenat somatotopia, que representa la posició de l’estímul sensorial. He demostrat que l’ordre de neurogènesi defineix la somatotopia. A més, he identificat dues subclasses de neurones sensorials de la línia lateral que presenten diferències en els seus patrons de projecció central i en els contactes amb una neurona central: la cèl·lula de Mauthner. Proposo que aquest dimorfisme és important per a donar lloc a reaccions comportamentals adients al context sensorial. També he demostrat una contribució per part de l’ordre de neurogènesi a la formació del mapa neuronal dimòrfic de la línia lateral. Finalment, he obtingut resultats que mostren que la diversitat neuronal i la topologia del mapa observades ocorren amb normalitat en l’absència d’activitat sensorial. Page

The new situation of globalisation brings to mind that artistic material generally is a limited repertoire of signs. This material defines the artistic world; it encompasses an interpretation of the world rooted in the artist’s regional culture. This situation therefore requires »possibilities of approaching the Other and the Self for which there are not any patterns yet«, as Kuno Lorenz writes. The alienation of the Self and the full identification with the Other may form intermediate stages of this process. My music theatre work Chief Joseph (2001-2003) is largely based on the theme of a confrontation between Self and Other. This theme is approached from a diversity of angles: its different forms, its conflicts, its creative impulses, its disastrous consequences and the utopia of its success. The example for this confrontion used in my opera – the wars between European settlers and aboriginal Indians in North America – is especially loaded with cliché-like valuations in our collective memory. The music does not reflect the theme »Self and Other« by way of polystylicism or quotations of »exotic« material. Rather, six types of scenes are established, each of which relates to a different concept of musical time – a reflection of the author’s observation that cultural differences often can be perceived less in surface forms, but rather in the ways cultures conceive of or construct time. These scene types, moreover, show parallels with Fritz Mauthner’s attempt to categorise language as three »images of the world«: the »Leerszenen« [empty scenes] which are grounded in silence coincide with Mauthner’s type »adjectival language«, the »Klagen« [laments] which concentrate on single constellations of intervals or pitches parallel Mauthner’s »substantival language«, the instable, floating »Recitative« [recitatives] hint at Mauthner’s »verbal language«, while the other scene types (»Indian Songs« and ensemble scenes including »Councils«) in Mauthner’s system would appear as mixed forms. A key position is taken by the scene-type »Rotationen« [rotations], with one rotation occurring in each of the three acts. They form a system on their own, remaining independent of the dramatic action and try to suggest an exterritorial perspective on the theme »Self and Other«.