TY - JOUR A1 - Elsner, Birgit A1 - Schellhas, Bernd T1 - The acquisition of flexible tool use in preschoolers the impact of prior experience JF - Zeitschrift für Psychologie = Journal of psychology N2 - To investigate how preschoolers acquire a tool use strategy and how they adapt their tool use to a changed situation, 2- to 4-year-olds were asked to retrieve chips from a transparent box with a rod, either by stabbing and lifting through a top opening or by pushing through a front and a back opening. In both conditions, about 40% of the children acquired effective tool use by individual learning, and 90% of the other children learned this by observing only one demonstration. When confronted with a changed situation (i.e., previous opening covered, alternative opening uncovered), children perseverated with the recently learned, but now ineffective tool use strategy. Neither age nor acquisition type of the first strategy affected preschoolers' perseverations. Results indicate that prior tool use experiences have differential effects in situations that require either transferring known functions to novel objects or using a familiar tool for an alternative purpose. KW - tool use KW - preschoolers (2-4 years) KW - learning KW - transfer KW - action planning Y1 - 2012 U6 - https://doi.org/10.1027/2151-2604/a000090 SN - 2190-8370 VL - 220 IS - 1 SP - 44 EP - 49 PB - Hogrefe CY - Göttingen ER - TY - GEN A1 - Heinzel, Stephan A1 - Rimpel, Jérôme A1 - Stelzel, Christine A1 - Rapp, Michael Armin T1 - Transfer Effects to a Multimodal Dual-Task after Working Memory Training and Associated Neural Correlates in Older Adults BT - A Pilot Study N2 - Working memory (WM) performance declines with age. However, several studies have shown that WM training may lead to performance increases not only in the trained task, but also in untrained cognitive transfer tasks. It has been suggested that transfer effects occur if training task and transfer task share specific processing components that are supposedly processed in the same brain areas. In the current study, we investigated whether single-task WM training and training-related alterations in neural activity might support performance in a dual-task setting, thus assessing transfer effects to higher-order control processes in the context of dual-task coordination. A sample of older adults (age 60–72) was assigned to either a training or control group. The training group participated in 12 sessions of an adaptive n-back training. At pre and post-measurement, a multimodal dual-task was performed in all participants to assess transfer effects. This task consisted of two simultaneous delayed match to sample WM tasks using two different stimulus modalities (visual and auditory) that were performed either in isolation (single-task) or in conjunction (dual-task). A subgroup also participated in functional magnetic resonance imaging (fMRI) during the performance of the n-back task before and after training. While no transfer to single-task performance was found, dual-task costs in both the visual modality (p < 0.05) and the auditory modality (p < 0.05) decreased at post-measurement in the training but not in the control group. In the fMRI subgroup of the training participants, neural activity changes in left dorsolateral prefrontal cortex (DLPFC) during one-back predicted post-training auditory dual-task costs, while neural activity changes in right DLPFC during three-back predicted visual dual-task costs. Results might indicate an improvement in central executive processing that could facilitate both WM and dual-task coordination. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 343 KW - aging KW - cognitive training KW - dual-task KW - fMRI KW - modality KW - neuroimaging KW - transfer KW - working memory Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-401921 ER - TY - JOUR A1 - Heinzel, Stephan A1 - Rimpel, Jérôme A1 - Stelzel, Christine A1 - Rapp, Michael Armin T1 - Transfer Effects to a Multimodal Dual-Task after Working Memory Training and Associated Neural Correlates in Older Adults BT - A Pilot Study JF - Frontiers in human neuroscience N2 - Working memory (WM) performance declines with age. However, several studies have shown that WM training may lead to performance increases not only in the trained task, but also in untrained cognitive transfer tasks. It has been suggested that transfer effects occur if training task and transfer task share specific processing components that are supposedly processed in the same brain areas. In the current study, we investigated whether single-task WM training and training-related alterations in neural activity might support performance in a dual-task setting, thus assessing transfer effects to higher-order control processes in the context of dual-task coordination. A sample of older adults (age 60–72) was assigned to either a training or control group. The training group participated in 12 sessions of an adaptive n-back training. At pre and post-measurement, a multimodal dual-task was performed in all participants to assess transfer effects. This task consisted of two simultaneous delayed match to sample WM tasks using two different stimulus modalities (visual and auditory) that were performed either in isolation (single-task) or in conjunction (dual-task). A subgroup also participated in functional magnetic resonance imaging (fMRI) during the performance of the n-back task before and after training. While no transfer to single-task performance was found, dual-task costs in both the visual modality (p < 0.05) and the auditory modality (p < 0.05) decreased at post-measurement in the training but not in the control group. In the fMRI subgroup of the training participants, neural activity changes in left dorsolateral prefrontal cortex (DLPFC) during one-back predicted post-training auditory dual-task costs, while neural activity changes in right DLPFC during three-back predicted visual dual-task costs. Results might indicate an improvement in central executive processing that could facilitate both WM and dual-task coordination. KW - working memory KW - cognitive training KW - modality KW - dual-task KW - aging KW - transfer KW - fMRI KW - neuroimaging Y1 - 2017 U6 - https://doi.org/10.3389/fnhum.2017.00085 VL - 11 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Yarman, Aysu A1 - Scheller, Frieder W. T1 - How reliable is the electrochemical readout of MIP sensors? JF - Sensors N2 - Electrochemical methods offer the simple characterization of the synthesis of molecularly imprinted polymers (MIPs) and the readouts of target binding. The binding of electroinactive analytes can be detected indirectly by their modulating effect on the diffusional permeability of a redox marker through thin MIP films. However, this process generates an overall signal, which may include nonspecific interactions with the nonimprinted surface and adsorption at the electrode surface in addition to (specific) binding to the cavities. Redox-active low-molecular-weight targets and metalloproteins enable a more specific direct quantification of their binding to MIPs by measuring the faradaic current. The in situ characterization of enzymes, MIP-based mimics of redox enzymes or enzyme-labeled targets, is based on the indication of an electroactive product. This approach allows the determination of both the activity of the bio(mimetic) catalyst and of the substrate concentration. KW - molecularly imprinted polymers KW - electropolymerization KW - direct electron KW - transfer KW - catalysis KW - redox marker KW - gate effect Y1 - 2020 U6 - https://doi.org/10.3390/s20092677 SN - 1424-8220 VL - 20 IS - 9 PB - MDPI CY - Basel ER - TY - JOUR A1 - Cheng, Chaojie A1 - Milsch, Harald T1 - Evolution of fracture aperture in quartz sandstone under hydrothermal conditions BT - mechanical and chemical effects JF - Minerals N2 - Fractures efficiently affect fluid flow in geological formations, and thereby determine mass and energy transport in reservoirs, which are not least exploited for economic resources. In this context, their response to mechanical and thermal changes, as well as fluid-rock interactions, is of paramount importance. In this study, a two-stage flow-through experiment was conducted on a pure quartz sandstone core of low matrix permeability, containing one single macroscopic tensile fracture. In the first short-term stage, the effects of mechanical and hydraulic aperture on pressure and temperature cycles were investigated. The purpose of the subsequent intermittent-flow long-term (140 days) stage was to constrain the evolution of the geometrical and hydraulic fracture properties resulting from pressure solution. Deionized water was used as the pore fluid, and permeability, as well as the effluent Si concentrations, were systematically measured. Overall, hydraulic aperture was shown to be significantly less affected by pressure, temperature and time, in comparison to mechanical aperture. During the long-term part of the experiment at 140 degrees C, the effluent Si concentrations likely reached a chemical equilibrium state within less than 8 days of stagnant flow, and exceeded the corresponding hydrostatic quartz solubility at this temperature. This implies that the pressure solution was active at the contacting fracture asperities, both at 140 degrees C and after cooling to 33 degrees C. The higher temperature yielded a higher dissolution rate and, consequently, a faster attainment of chemical equilibrium within the contact fluid. X-ray mu CT observations evidenced a noticeable increase in fracture contact area ratio, which, in combination with theoretical considerations, implies a significant decrease in mechanical aperture. In contrast, the sample permeability, and thus the hydraulic fracture aperture, virtually did not vary. In conclusion, pressure solution-induced fracture aperture changes are affected by the degree of time-dependent variations in pore fluid composition. In contrast to the present case of a quasi-closed system with mostly stagnant flow, in an open system with continuous once-through fluid flow, the activity of the pressure solution may be amplified due to the persistent fluid-chemical nonequilibrium state, thus possibly enhancing aperture and fracture permeability changes. KW - flow-through experiment KW - fracture aperture KW - pressure solution KW - mass KW - transfer KW - silica concentration KW - permeability KW - quartz sandstone Y1 - 2020 U6 - https://doi.org/10.3390/min10080657 SN - 2075-163X VL - 10 IS - 8 PB - MDPI CY - Basel ER - TY - JOUR A1 - Bürki-Foschini, Audrey Damaris A1 - Viebahn, Malte Clemens A1 - Gafos, Adamantios I. T1 - Plasticity and transfer in the sound system BT - exposure to syllables in production or perception changes their subsequent production JF - Language, cognition and neuroscience N2 - This study focuses on the ability of the adult sound system to reorganise as a result of experience. Participants were exposed to existing and novel syllables in either a listening task or a production task over the course of two days. On the third day, they named disyllabic pseudowords while their electroencephalogram was recorded. The first syllable of these pseudowords had either been trained in the auditory modality, trained in production or had not been trained. The EEG response differed between existing and novel syllables for untrained but not for trained syllables, indicating that training novel sound sequences modifies the processes involved in the production of these sequences to make them more similar to those underlying the production of existing sound sequences. Effects of training on the EEG response were observed both after production training and mere auditory exposure. KW - Language production KW - EEG KW - syllables KW - phonetic encoding KW - transfer Y1 - 2020 U6 - https://doi.org/10.1080/23273798.2020.1782445 SN - 2327-3798 SN - 2327-3801 VL - 35 IS - 10 SP - 1371 EP - 1393 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - THES A1 - Gonzalez Duran, Enrique T1 - Genetic control of intracellular gene transfer by DNA repair in N. tabacum N2 - Mitochondria and plastids are organelles with an endosymbiotic origin. During evolution, many genes are lost from the organellar genomes and get integrated in the nuclear genome, in what is known as intracellular/endosymbiotic gene transfer (IGT/EGT). IGT has been reproduced experimentally in Nicotiana tabacum at a gene transfer rate (GTR) of 1 event in 5 million cells, but, despite its centrality to eukaryotic evolution, there are no genetic factors known to influence the frequency of IGT in higher eukaryotes. The focus of this work was to determine the role of different DNA repair pathways of double strand break repair (DSBR) in the integration step of organellar DNA in the nuclear genome during IGT. Here, a CRISPR/Cas9 mutagenesis strategy was implemented in N. tabacum, with the aim of generating mutants in nuclear genes without expected visible phenotypes. This strategy led to the generation of a collection of independent mutants in the LIG4 (necessary for non-homologous end joining, NHEJ) and POLQ genes (necessary for microhomology mediated end joining, MMEJ). Targeting of other DSBR genes (KU70, KU80, RPA1C) generated mutants with unexpectedly strong developmental phenotypes.. These factors have telomeric roles, hinting towards a possible relationship between telomere length, and strength of developmental disruption upon loss of telomere structure in plants. The mutants were made in a genetic background encoding a plastid-encoded IGT reporter, that confers kanamycin resistance upon transfer to the nucleus. Through large scale independent experiments, increased IGT from the chloroplast to the nucleus was observed in lig4 mutants, as well as lines encoding a POLQ gene with a defective polymerase domain (polqΔPol). This shows that NHEJ or MMEJ have a double-sided relationship with IGT: while transferred genes may integrate using either pathway, the presence of both pathways suppresses IGT in wild-type somatic cells, thus demonstrating for the first time the extent on which nuclear genes control IGT frequency in plants. The IGT frequency increases in the mutants are likely mediated by increased availability of double strand breaks for integration. Additionally, kinetic analysis reveals that gene transfer (GT) events accumulate linearly as a function of time spent under antibiotic selection in the experiment, demonstrating that, contrary to what was previously thought, there is no such thing as a single GTR in somatic IGT experiments. Furthermore, IGT in tissue culture experiments appears to be the result of a "race against the clock" for integration in the nuclear genome, that starts when the organellar DNA arrives to the nucleus granting transient antibiotic resistance. GT events and escapes of kanamycin selection may be two possible outcomes from this race: those instances where the organellar DNA gets to integrate are recovered as GT events, and in those cases where timely integration fails, antibiotic resistance cannot be sustained, and end up considered as escapes. In the mutants, increased opportunities for integration in the nuclear genome change the overall ratio between IGT and escape events. The resources generated here are promising starting points for future research: (1) the mutant collection, for the further study of processes that depend on DNA repair in plants (2) the collection of GT lines obtained from these experiments, for the study of the effect of DSBR pathways over integration patterns and stability of transferred genes and (3) the developed CRISPR/Cas9 workflow for mutant generation, to make N. tabacum meet its potential as an attractive model for answering complex biological questions. N2 - Mitochondrien und Plastiden sind beides Organellen endosymbiotischen Ursprungs. Im Laufe der Evolution gehen viele Gene aus den Organellengenomen verloren und werden in das Kerngenom integriert, was als intrazellulärer/endosymbiotischer Gentransfer (IGT/EGT) bezeichnet wird. IGT konnte experimentell in Nicotiana tabacum mit einer Gentransferrate (GTR) von einem Ereignis in fünf Millionen Zellen nachgestellt werden, aber trotz seiner zentralen Bedeutung für die eukaryotische Evolution sind keine genetischen Faktoren bekannt, die die Häufigkeit von IGT in höheren Eukaryoten beeinflussen. Der Schwerpunkt dieser Arbeit lag auf der Bestimmung der Rolle verschiedener DNA-Reparaturwege der Doppelstrangbruchreparatur (DSBR) bei der Integration von Organellen-DNA in das Kerngenom während des IGT. Dazu wurde in N. tabacum eine CRISPR/Cas9-basierte Mutagenesestrategie angewandt, mit dem Ziel, Mutanten in Kerngenen zu erzeugen, für die keine sichtbaren Phänotypen zu erwarten sind. Diese Strategie führte zur Erzeugung einer Reihe unabhängiger Mutanten im LIG4-Gen (notwendig für „non-homologous end joining“, die nicht-homologe Verbindung von Enden, NHEJ) und POLQ (notwendig für „microhomology mediated end joining“, die Mikrohomologie-vermittelte Verbindung von Enden, MMEJ). Die gezielte Beeinflussung anderer DSBR-Gene (KU70, KU80, RPA1C) führte zu Mutanten mit unerwartet starken Entwicklungsphänotypen. Diese Gene spielen eine Rolle beim Erhalt der Telomere, was auf einen möglichen Zusammenhang zwischen der Telomerlänge und der Stärke der Entwicklungsstörung bei Verlust der Telomerstruktur in Pflanzen hindeutet. Die Mutanten wurden in einem genetischen Hintergrund erzeugt, der über einen in den Plastiden lokalisierten IGT-Reporter verfügt, der nach Übertragung in den Zellkern Kanamycin-Resistenz vermittelt. In groß angelegten unabhängigen Experimenten wurde in lig4-Mutanten sowie in Linien, die für ein POLQ-Gen mit einer defekten Polymerase-Domäne (polqΔPol) kodieren, eine erhöhte GTR vom Chloroplasten zum Zellkern beobachtet. Dies zeigt, dass NHEJ oder MMEJ eine zweischneidige Beziehung zum IGT haben: Während übertragene Gene folglich über jeden der beiden Mechanismen integriert werden können, unterdrückt das gleichzeitige Vorhandensein beider Wege IGT in somatischen Wildtyp-Zellen, wodurch zum ersten Mal gezeigt wird, in welchem Ausmaß Kerngene die IGT-Häufigkeit in Pflanzen kontrollieren. Die erhöhte Verfügbarkeit von Doppelstrangbrüchen für die Integration könnte für die erhöhte IGT-Häufigkeit in den Mutanten verantwortlich sein. Darüber hinaus zeigt die Analyse des Zeitverlaufs, dass Gentransferereignisse (GT) in Abhängigkeit von der Zeit, die im Experiment unter Antibiotikaselektion verbracht wurde, linear akkumulieren, was beweist, dass es, anders als bisher angenommen, in somatischen IGT-Experimenten keine statische GTR gibt. Darüber hinaus scheint IGT in Gewebekulturexperimenten das Ergebnis eines Wettlaufs mit der Zeit um die Integration in das Kerngenom zu sein, der beginnt, wenn die Organellen-DNA in den Zellkern gelangt und eine vorübergehende Antibiotikaresistenz gewährt. Echte GT-Ereignisse und „Escapes“ (scheinbare Resistenz, ein vorläufiges Ausweichen vor der Kanamycin-Selektion) können zwei mögliche Ergebnisse dieses Wettlaufs sein: Die Fälle, in denen die Organellen-DNA integriert wird, werden als GT-Ereignisse gewertet, und in den Fällen, in denen die rechtzeitige Integration scheitert, kann die Antibiotikaresistenz nicht aufrechterhalten werden und sie werden als „Escape“ betrachtet. In den Mutanten verändern sich die Möglichkeiten zur Integration in das Kerngenom, wodurch sich das Gesamtverhältnis zwischen IGT- und „Escape“-Ereignissen ändert. Die hier erzeugten Ressourcen sind vielversprechende Ausgangspunkte für künftige Forschungen: (1) die Mutantensammlung, für die Untersuchung von weiteren Prozessen, die von der DNA-Reparatur in Pflanzen abhängen, (2) die Sammlung von GT-Linien, die aus den hier beschriebenen Experimenten gewonnen wurden, für die Untersuchung der Auswirkungen von DSBR-Mechanismen auf Integrationsmuster und Stabilität übertragener Gene und (3) der hier entwickelte Arbeitsablauf für die Mutantenerzeugung mittels CRISPR/Cas9, damit N. tabacum sein Potenzial als attraktives Modell für die Beantwortung komplexer biologischer Fragestellungen erfüllen kann. T2 - Genetische Kontrolle des intrazellulären Gentransfers durch DNA-Reparatur in N. tabacum KW - endosymbiosis KW - organelles KW - gene KW - transfer KW - DNA KW - repair KW - genome KW - editing KW - evolution KW - plant Y1 - 2023 ER -