203 results match your criteria: "Humboldt-University at Berlin[Affiliation]"

Face cognition is considered a specific human ability, clearly differentiable from general cognitive functioning. Its specificity is primarily supported by cognitive-experimental and neuroimaging research, but recently also from an individual differences perspective. However, no comprehensive behavioral data are available, which would allow estimating lifespan changes of the covariance structure of face-cognition abilities and general cognitive functioning as well as age-differences in face cognition after accounting for interindividual variability in general cognition.

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The recent years have seen the emergence of graph theoretical analysis of complex, functional brain networks estimated from neurophysiological measurements. The research has mainly focused on the graph characterization of the resting-state/default network, and its potential for clinical application. Functional resting-state networks usually display the characteristics of small-world networks and their statistical properties have been observed to change due to pathological conditions or aging.

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Perceiving and memorizing faces swiftly and correctly are important social competencies. The organization of these interpersonal abilities and how they change across the life span are still poorly understood. We investigated changes in the mean and covariance structure of face cognition abilities across the adult life span.

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What is the speed of link between aboveground and belowground processes?

New Phytol

September 2010

Institute of Plant, Animal and Agroecosystem Sciences, LFW C56, ETH Zurich, Universitaetsstrasse 2, 8092 Zurich, Switzerland.

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Conspicuously absent from face recognition research is a direct comparison of well-known faces with newly learned faces for which the associated biographical knowledge and the perceptual expertise were experimentally manipulated. Such a comparison can test competing assumptions made by serial and interactive activation and competition (IAC) models about the role of previous experience and biographical knowledge in face recognition. We measured behavioral performance and event-related potentials (ERPs) for four classes of faces: unfamiliar faces, faces of celebrities, and two classes of experimentally familiarized faces learned one week prior to the recognition test either with or without associated biographical knowledge.

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The impact of intervening tasks on response preparation.

J Exp Psychol Hum Percept Perform

April 2010

Institut fur Psychologie, Humboldt University at Berlin, Germany.

Response preparation usually facilitates performance, but it may also interfere with other concurrent tasks. In this article, the authors used event-related brain potentials to study how intervening tasks affect response preparation. In 3 experiments, participants performed intervening tasks during the preparation of a precued hand choice response.

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We present a discrete model of stochastic excitability by a low-dimensional set of delayed integral equations governing the probability in the rest state, the excited state, and the refractory state. The process is a random walk with discrete states and nonexponential waiting time distributions, which lead to the incorporation of memory kernels in the integral equations. We extend the equations of a single unit to the system of equations for an ensemble of globally coupled oscillators, derive the mean field equations, and investigate bifurcations of steady states.

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Life-history traits and energetic status in relation to vulnerability to angling in an experimentally selected teleost fish.

Evol Appl

August 2009

Division of Ecology and Conservation Sciences, Illinois Natural History Survey Champaign, IL, USA ; Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign Urbana, IL, USA.

In recreational fisheries, a correlation has been established between fishing-induced selection pressures and the metabolic traits of individual fish. This study used a population of largemouth bass (Micropterus salmoides) with lines of low vulnerability fish (LVF) and high vulnerability fish (HVF) that were previously established through artificial truncation selection experiments. The main objective was to evaluate if differential vulnerability to angling was correlated with growth, energetics and nutritional condition during the sub-adult stage.

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Phase reversal in the Selkov model with inhomogeneous influx.

Phys Rev E Stat Nonlin Soft Matter Phys

May 2009

Institute of Physics, Humboldt-University at Berlin, Newtonstr. 15, 12489 Berlin, Germany.

The dynamical reaction-diffusion Selkov system as a model describing the complex traveling wave behavior is presented. The approximate amplitude-phase solution allows us to extract the base properties of the biochemical distributed system, which determines such patterns. It is shown that this relatively simple model could describe qualitatively the main features of the glycolysis waves observed in the experiments.

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The spatio-temporal dynamics of traveling waves in glycolysis as it occurs in yeast extract have been studied, both theoretically and experimentally. We describe this phenomenon with the distributed Selkov model that accounts for the reactions of phosphofructokinase, which is a key enzyme of the glycolytic reaction cascade. To describe the experimentally observed phase waves in an open spatial reactor we introduce a non-homogeneous flux of substrate in the model.

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The emotional content of stimuli influences cognitive performance. In two experiments, we investigated the time course and mechanisms of emotional influences on visual word processing in various tasks by recording event-related brain potentials (ERPs). The stimuli were verbs of positive, negative, and neutral valence.

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Emotions in word and face processing: early and late cortical responses.

Brain Cogn

April 2009

Department of Psychology, Humboldt-University at Berlin, Rudower Chaussee 18, D-12489 Berlin, Germany.

Recent research suggests that emotion effects in word processing resemble those in other stimulus domains such as pictures or faces. The present study aims to provide more direct evidence for this notion by comparing emotion effects in word and face processing in a within-subject design. Event-related brain potentials (ERPs) were recorded as participants made decisions on the lexicality of emotionally positive, negative, and neutral German verbs or pseudowords, and on the integrity of intact happy, angry, and neutral faces or slightly distorted faces.

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Emotions in Go/NoGo conflicts.

Psychol Res

November 2009

Department of Psychology, Humboldt-University at Berlin, Rudower Chaussee 18, 10099 Berlin, Germany.

On the basis of current emotion theories and functional and neurophysiological ties between the processing of conflicts and errors on the one hand and errors and emotions on the other hand we predicted that conflicts between prepotent Go responses and occasional NoGo trials in the Go/NoGo task would induce emotions. Skin conductance responses (SCRs), corrugator muscle activity, and startle blink responses were measured in three experiments requiring speeded Go responses intermixed with NoGo trials of different relative probability and in a choice reaction experiment serving as a control. NoGo trials affected several of these emotion-sensitive indicators as SCRs and startle blinks were reduced whereas corrugator activity was prolonged as compared to Go trials.

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Facial attractiveness is an important source of social affective information. Here, we studied the time course and task dependence of evaluating attractive faces from a viewer's perspective. Event-related brain potentials (ERPs) were recorded while participants classified color portraits of unfamiliar persons according to gender and facial attractiveness.

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In order to test the frequent assumption that lexical access in visual word recognition would proceed independent of central attention, the overlapping task paradigm has recently been employed with somewhat contradictory results. Here we combined overlapping tasks with the recording of event-related brain potentials to assess task load dependent modulations of lexical access in more detail. The study was carried out in Spanish with native Spanish speaking participants.

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Humic substances. Part 2: Interactions with organisms.

Environ Sci Pollut Res Int

March 2008

Humboldt University at Berlin, Institute of Biology, Freshwater and Stress Ecology, Germany.

Goal, Scope And Background: Freshwater bodies which chemistry is dominated by dissolved humic substances (HS) seem to be the major type on Earth, due to huge non-calcareous geological formations in the Northern Hemisphere and in the tropics. Based on the paradigm of the inertness of being organic, direct interactions of dissolved HS with freshwater organisms are mostly neglected. However, dissolved organic carbon, the majority of which being HS, are natural environmental chemicals and should therefore directly interact with organisms.

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Humic substances in the environment with an emphasis on freshwater systems.

Environ Sci Pollut Res Int

January 2008

Humboldt University at Berlin, Institute of Biology, Freshwater and Stress Ecology, Arboretum, Späthstr. 80/81, 12437 Berlin, Germany.

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Cytochrome P450-dependent metabolism of eicosapentaenoic acid in the nematode Caenorhabditis elegans.

Arch Biochem Biophys

April 2008

Humboldt University at Berlin, Department of Biology, Freshwater and Stress Ecology, Spaethstr. 80/81, 12437 Berlin, Germany.

The genome of Caenorhabditis elegans contains 75 full length cytochrome P450 (CYP) genes whose individual functions are largely unknown yet. We tested the hypothesis that some of them may be involved in the metabolism of eicosapentaenoic acid (EPA), the predominant polyunsaturated fatty acid of this nematode. Microsomes isolated from adult worms contained spectrally active CYP proteins and showed NADPH-CYP reductase (CPR) activities.

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There is mounting evidence that under some conditions the processing of facial identity and facial emotional expressions may not be independent; however, the nature of this interaction remains to be established. By using event-related brain potentials (ERP) we attempted to localize these interactions within the information processing system. During an expression discrimination task (Experiment 1) categorization was faster for portraits of personally familiar vs.

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Memory for faces and names has increasingly become a focus of cognitive assessment and research in Alzheimer's disease (AD). This paper reviews evidence from cognitive and clinical neuroscience regarding the question of whether AD is associated with a specific deficit in face recognition, face-name association, and retrieval of semantic information and names. Cognitive approaches conceptualizing face recognition and face-name association have revealed that, compared to other types of visual stimuli, faces are "special" because of their complexity and high intraclass similarity, and because their association with proper names is arbitrary and unique.

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The role of the spiracles in gas exchange during development of Samia cynthia (Lepidoptera, Saturniidae).

Comp Biochem Physiol A Mol Integr Physiol

December 2007

Department of Animal Physiology, Humboldt-University at Berlin, Philippstrasse 13, 10115 Berlin, Germany.

Spiracles and the tracheal system of insects allow effective delivery of respiratory gases. During development, holometabolous insects encounter large changes in the functional morphology of gas exchange structures. To investigate changes in respiratory patterns during development, CO2-release was measured in larvae, pre-pupae and pupae of Samia cynthia (Lepidoptera, Saturniidae).

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Scripts are mental representations of activities in memory and are thought to be organized dimensionally in a temporal dimension. We investigated the cognitive strategies during the processing of temporal order of an event sequence to gain insight into the organization of scripts. Subjects were presented with triplets of script events (A - B - C).

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Facial attractiveness modulates early and late event-related brain potentials.

Biol Psychol

September 2007

Department of Psychology, Humboldt-University at Berlin, Rudower Chaussee 18, 12489 Berlin, Germany.

Facial attractiveness is of high importance for human interaction and communication, and everyday experience suggests that the mere aspect of a face elicits spontaneous appraisal of attractiveness. However, little is known about the time course of brain responses related to this process. In the present study, event-related brain potentials were recorded during attractiveness classification of facial portraits that were standardized with respect to facial expression.

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Practice effects on dual-task processing are of interest in current research because they may reveal the scope and limits of parallel task processing. Here we used onsets of the lateralized readiness potential (LRP), a time marker for the termination of response selection, to assess processing changes after five consecutive dual-task sessions with three stimulus onset asynchronies (SOAs) and priority on Task 1. Practice reduced reaction times in both tasks and the interference between tasks.

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