University of Konstanz

About: University of Konstanz is a education organization based out in Konstanz, Baden-Württemberg, Germany. It is known for research contribution in the topics: Population & Membrane. The organization has 12115 authors who have published 27401 publications receiving 951162 citations. The organization is also known as: University of Constance & Universität Konstanz.

The complete connectome of a learning and memory centre in an insect brain

Abstract: Associating stimuli with positive or negative reinforcement is essential for survival, but a complete wiring diagram of a higher-order circuit supporting associative memory has not been previously available Here we reconstruct one such circuit at synaptic resolution, the Drosophila larval mushroom body We find that most Kenyon cells integrate random combinations of inputs but that a subset receives stereotyped inputs from single projection neurons This organization maximizes performance of a model output neuron on a stimulus discrimination task We also report a novel canonical circuit in each mushroom body compartment with previously unidentified connections: reciprocal Kenyon cell to modulatory neuron connections, modulatory neuron to output neuron connections, and a surprisingly high number of recurrent connections between Kenyon cells Stereotyped connections found between output neurons could enhance the selection of learned behaviours The complete circuit map of the mushroom body should guide future functional studies of this learning and memory centre

Global rules and private actors: Toward a new role of the transnational corporation in global governance

Abstract: Economic activities require the existence of rules and their enforcement as preconditions that the market cannot generate itself. Property rights, and contractual rights and obligations, are minimal prerequisites for modern societies that are provided and enforced by the state. Without such prerequisites, the market cannot flourish. The state thus determines regulations and delineates the sphere of private freedom, within which individual citizens and private institutions are entitled to conclude contracts with one another, to which the system of property and contractual rights compels obedience. In the development of modern nation states, the state has not only been the guarantor of civil rights, e. g. the right to own property, to enter into private contracts, and to engage in market activity. In its role as a democratic constitutional state, it has also been the guarantor of political participation rights, the right of the citizen to take part in the processes that determine public rules and issues of public concern. Finally, in its role as a welfare state, it has provided social rights for citizens, such as the right to education, to health care, and to other forms of welfare (Marshall 1965). The combination of state-guaranteed civil, political, and social rights has provided legitimacy, solidarity, and welfare to modern society, thereby contributing to peaceful, stable communities of anonymous individuals (Habermas 2001). Following Matten and Crane (Matten/Crane 2005) we refer to this triad of rights as citizenship rights.

Cell behaviour on micropatterned substrata: limits of extracellular matrix geometry for spreading and adhesion

Abstract: Cell adhesion, spreading and migration require the dynamic formation and dispersal of contacts with the extracellular matrix (ECM). In vivo, the number, availability and distribution of ECM binding sites dictate the shape of a cell and determine its mobility. To analyse the geometrical limits of ECM binding sites required for cell attachment and spreading, we used microcontact printing to produce regular patterns of ECM protein dots of defined size separated by nonadhesive regions. Cells cultured on these substrata adhere to and spread on ECM regions as small as 0.1 microm2, when spacing between dots is less than 5 microm. Spacing of 5-25 microm induces a cell to adapt its shape to the ECM pattern. The ability to spread and migrate on dots > or =1 microm2 ceases when the dot separation is > or =30 microm. The extent of cell spreading is directly correlated to the total substratum coverage with ECM-proteins, but irrespective of the geometrical pattern. An optimal spreading extent is reached at a surface coating above 15%. Knowledge of these geometrical limits is essential for an understanding of cell adhesion and migration, and for the design of artificial surfaces that optimally interact with cells in a living tissue.

Rashba Effect in the Graphene/Ni(111) System

Abstract: We report on angle-resolved photoemission studies of the electronic $\ensuremath{\pi}$ states of high-quality epitaxial graphene layers on a Ni(111) surface. In this system the electron binding energy of the $\ensuremath{\pi}$ states shows a strong dependence on the magnetization reversal of the Ni film. The observed extraordinarily large energy shift up to 225 meV of the graphene-derived $\ensuremath{\pi}$ band peak position for opposite magnetization directions is attributed to a manifestation of the Rashba interaction between spin-polarized electrons in the $\ensuremath{\pi}$ band and the large effective electric field at the graphene/Ni interface. Our findings show that an electron spin in the graphene layer can be manipulated in a controlled way and have important implications for graphene-based spintronic devices.

Oscillatory power decreases and long-term memory: the information via desynchronization hypothesis

Abstract: The traditional belief is that brain oscillations are important for human long-term memory, because they induce synchronized firing between cell assemblies which shapes synaptic plasticity. Therefore, most prior studies focused on the role of synchronization for episodic memory, as reflected in theta (∼5 Hz) and gamma (>40 Hz) power increases. These studies, however, neglect the role that is played by neural desynchronization, which is usually reflected in power decreases in the alpha and beta frequency band (8-30 Hz). In this paper we present a first idea, derived from information theory that gives a mechanistic explanation of how neural desynchronization aids human memory encoding and retrieval. Thereby we will review current studies investigating the role of alpha and beta power decreases during long-term memory tasks and show that alpha and beta power decreases play an important and active role for human memory. Applying mathematical models of information theory, we demonstrate that neural desynchronization is positively related to the richness of information represented in the brain, thereby enabling encoding and retrieval of long-term memories. This information via desynchronization hypothesis makes several predictions, which can be tested in future experiments.