31,685 research outputs found

    Realizing moral values: on acting persons and moral values in Max Scheler's ethics

    Get PDF
    This article explores some aspects of how Max Scheler conceived of the relationship between persons and actions. The primary source to do so is Scheler’s Formalism in Ethics and Non-Formal Ethics of Values, but it will also be observed that the concept of the person as an act-accomplishing being figures as a leitmotiv in Scheler’s entire oeuvre: from the writings on sympathy and love to the late writings in which Scheler developed his controversial metaphysics

    Logarithmic distributions prove that intrinsic learning is Hebbian

    Full text link
    In this paper, we present data for the lognormal distributions of spike rates, synaptic weights and intrinsic excitability (gain) for neurons in various brain areas, such as auditory or visual cortex, hippocampus, cerebellum, striatum, midbrain nuclei. We find a remarkable consistency of heavy-tailed, specifically lognormal, distributions for rates, weights and gains in all brain areas examined. The difference between strongly recurrent and feed-forward connectivity (cortex vs. striatum and cerebellum), neurotransmitter (GABA (striatum) or glutamate (cortex)) or the level of activation (low in cortex, high in Purkinje cells and midbrain nuclei) turns out to be irrelevant for this feature. Logarithmic scale distribution of weights and gains appears to be a general, functional property in all cases analyzed. We then created a generic neural model to investigate adaptive learning rules that create and maintain lognormal distributions. We conclusively demonstrate that not only weights, but also intrinsic gains, need to have strong Hebbian learning in order to produce and maintain the experimentally attested distributions. This provides a solution to the long-standing question about the type of plasticity exhibited by intrinsic excitability

    Self-organization of signal transduction

    Full text link
    We propose a model of parameter learning for signal transduction, where the objective function is defined by signal transmission efficiency. We apply this to learn kinetic rates as a form of evolutionary learning, and look for parameters which satisfy the objective. This is a novel approach compared to the usual technique of adjusting parameters only on the basis of experimental data. The resulting model is self-organizing, i.e. perturbations in protein concentrations or changes in extracellular signaling will automatically lead to adaptation. We systematically perturb protein concentrations and observe the response of the system. We find compensatory or co-regulation of protein expression levels. In a novel experiment, we alter the distribution of extracellular signaling, and observe adaptation based on optimizing signal transmission. We also discuss the relationship between signaling with and without transients. Signaling by transients may involve maximization of signal transmission efficiency for the peak response, but a minimization in steady-state responses. With an appropriate objective function, this can also be achieved by concentration adjustment. Self-organizing systems may be predictive of unwanted drug interference effects, since they aim to mimic complex cellular adaptation in a unified way.Comment: updated version, 13 pages, 4 figures, 3 Tables, supplemental tabl

    Regulation of Neuromodulator Receptor Efficacy - Implications for Whole-Neuron and Synaptic Plasticity

    Full text link
    Membrane receptors for neuromodulators (NM) are highly regulated in their distribution and efficacy - a phenomenon which influences the individual cell's response to central signals of NM release. Even though NM receptor regulation is implicated in the pharmacological action of many drugs, and is also known to be influenced by various environmental factors, its functional consequences and modes of action are not well understood. In this paper we summarize relevant experimental evidence on NM receptor regulation (specifically dopamine D1 and D2 receptors) in order to explore its significance for neural and synaptic plasticity. We identify the relevant components of NM receptor regulation (receptor phosphorylation, receptor trafficking and sensitization of second-messenger pathways) gained from studies on cultured cells. Key principles in the regulation and control of short-term plasticity (sensitization) are identified, and a model is presented which employs direct and indirect feedback regulation of receptor efficacy. We also discuss long-term plasticity which involves shifts in receptor sensitivity and loss of responsivity to NM signals. Finally, we discuss the implications of NM receptor regulation for models of brain plasticity and memorization. We emphasize that a realistic model of brain plasticity will have to go beyond Hebbian models of long-term potentiation and depression. Plasticity in the distribution and efficacy of NM receptors may provide another important source of functional plasticity with implications for learning and memory.Comment: 35 page

    Dopaminergic Regulation of Neuronal Circuits in Prefrontal Cortex

    Get PDF
    Neuromodulators, like dopamine, have considerable influence on the\ud processing capabilities of neural networks. \ud This has for instance been shown in the working memory functions\ud of prefrontal cortex, which may be regulated by altering the\ud dopamine level. Experimental work provides evidence on the biochemical\ud and electrophysiological actions of dopamine receptors, but there are few \ud theories concerning their significance for computational properties \ud (ServanPrintzCohen90,Hasselmo94).\ud We point to experimental data on neuromodulatory regulation of \ud temporal properties of excitatory neurons and depolarization of inhibitory \ud neurons, and suggest computational models employing these effects.\ud Changes in membrane potential may be modelled by the firing threshold,\ud and temporal properties by a parameterization of neuronal responsiveness \ud according to the preceding spike interval.\ud We apply these concepts to two examples using spiking neural networks.\ud In the first case, there is a change in the input synchronization of\ud neuronal groups, which leads to\ud changes in the formation of synchronized neuronal ensembles.\ud In the second case, the threshold\ud of interneurons influences lateral inhibition, and the switch from a \ud winner-take-all network to a parallel feedforward mode of processing.\ud Both concepts are interesting for the modeling of cognitive functions and may\ud have explanatory power for behavioral changes associated with dopamine \ud regulation

    La estructura acto-objeto como estructura de la intelección en Scheler y Polo

    Get PDF
    Tanto Scheler como Polo aceptan la estructura acto-objeto para explicar el conocimiento intelectual. Pero no la entienden del mismo modo. Scheler defiende la prioridad del objeto (el objeto se da) y Polo la del acto (la operación presenta el objeto). Para Scheler el acto es intencional y para Polo lo es el objeto. Ambos detectan que esta estructura tiene un límite, porque el acto no es nunca el objeto.Both Scheler and Polo use the act-object structure to explain the intelectual knowledge. Nevertheless, they don’t understand this structure on the same way. Scheler holds the priority of the object (the object is given by itself) and Polo on his behalf holds the priority of the act (the operation presentates the object). For Scheler the act is intentional, but for Polo which is intentional is the object. Both observe that this structure has a limit, because the act is never the object

    La fenomenología de los sentimientos en Max Scheler y el concepto de afección en Martin Heidegger

    Get PDF
    A partir de los textos en los que aparecen comentarios importantes de Heidegger sobre Scheler y de Scheler sobre Heidegger, el autor de este artículo establece una comparación y contraposición entre ambos pensadores. Resalta particularmente la coincidencia de los dos en afirmar que el mundo se abre desde un sentimiento o una afección fundamental: el amor en Scheler y la angustia en Heidegger.The present text establishes a comparison and contrast between Heidegger and Scheler, giving special attention to the remarks of Heidegger to Scheler and vice versa. Particulary, throws into relief the common idea of both philosophers that the world opens through a feeling or fundamentl affection: love in Scheler and anxiety in Heidegger

    Rational a priori or Emotional a priori? Husserl and Scheler’s Criticisms of Kant Regarding the Foundation of Ethics

    Get PDF
    Based on the dispute between Protagoras and Socrates on the origin of ethics, one can ask the question of whether the principle of ethics is reason orfeeling/emotion, or whether ethics is grounded on reason or feeling/emotion. The development of Kant’s thoughts on ethics shows the tension between reason and feeling/emotion. In Kant’s final critical ethics, he held to a principle of “rational a priori.” On the one hand, this is presented as the rational a priori principle being the binding principle of judgment. On the other hand, it is presented as the doctrine of “rational fact” as the ultimate argument of his ethics. Husserl believed that Kant’s doctrine of a rational a priori totally disregarded the a priori essential laws of feeling. Like Husserl, Scheler criticized Kant’s doctrine of a rational a priori, and therefore developed his own theory of an “emotional a priori”. Both of them focused their critiques on the grounding level of ethics. Scheler, however, did not follow Husserl all the way, but criticized him and reflected on his thoughts. At last, he revealed the primary status of a phenomenological material ethics of value
    corecore