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Learning with digital media has become a substantial part of formal and informal educational processes and is gaining more and more importance. Technological progress has brought overwhelming opportunities for learners, but challenges them at the same time. Learners have to regulate their learning process to a much greater extent than in traditional learning situations in which teachers support them through external regulation. This means that learners must plan their learning process themselves, apply appropriate learning strategies, monitor, control and evaluate it. These requirements are taken into account in various models of self-regulated learning (SRL). Although the roots of research on SRL go back to the 1980s, the measurement and adequate support of SRL in technology-enhanced learning environments is still not solved in a satisfactory way. An important obstacle are the data sources used to operationalize SRL processes. In order to support SRL in adaptive learning systems and to validate theoretical models, instruments are needed which meet the classical quality criteria and also fulfil additional requirements. Suitable data channels must be measurable "online", i.e., they must be available in real time during learning for analyses or the individual adaptation of interventions. Researchers no longer only have an interest in the final results of questionnaires or tasks, but also need to examine process data from interactions between learners and learning environments in order to advance the development of theories and interventions. In addition, data sources should not be obtrusive so that the learning process is not interrupted or disturbed. Measurements of physiological data, for example, require learners to wear measuring devices. Moreover, measurements should not be reactive. This means that other variables such as learning outcomes should not be influenced by the measurement. Different data sources that are already used to study and support SRL processes, such as protocols on thinking aloud, screen recording, eye tracking, log files, video observations or physiological sensors, meet these criteria to varying degrees. One data channel that has received little attention in research on educational psychology, but is non-obtrusive, non-reactive, objective and available online, is the detailed, timely high-resolution data on observable interactions of learners in online learning environments. This data channel is introduced in this thesis as "peripheral data". It records both the content of learning environments as context, and related actions of learners triggered by mouse and keyboard, as well as the reactions of learning environments, such as structural or content changes. Although the above criteria for the use of the data are met, it is unclear whether this data can be interpreted reliably and validly with regard to relevant variables and behavior.
Therefore, the aim of this dissertation is to examine this data channel from the perspective of SRL and thus further close the existing research gap. One development project and four research projects were carried out and documented in this thesis.
Most natural learning situations are of a complex nature and consist of a tight conjunction of the animal's behavior (B) with the perceived stimuli. According to the behavior of the animal in response to these stimuli, they are classified as being either biologically neutral (conditioned stimuli, CS) or important (unconditioned stimuli, US or reinforcer). A typical learning situation is thus identified by a three term contingency of B, CS and US. A functional characterization of the single associations during conditioning in such a three term contingency has so far hardly been possible. Therefore, the operational distinction between classical conditioning as a behavior-independent learning process (CS-US associations) and operant conditioning as essentially behavior-dependent learning (B-US associations) has proven very valuable. However, most learning experiments described so far have not been successful in fully separating operant from classical conditioning into single-association tasks. The Drosophila flight simulator in which the relevant behavior is a single motor variable (yaw torque), allows for the first time to completely separate the operant (B-US, B-CS) and the classical (CS-US) components of a complex learning situation and to examine their interactions. In this thesis the contributions of the single associations (CS-US, B-US and B-CS) to memory formation are studied. Moreover, for the first time a particularly prominent single association (CS-US) is characterized extensively in a three term contingency. A yoked control shows that classical (CS-US) pattern learning requires more training than operant pattern learning. Additionally, it can be demonstrated that an operantly trained stimulus can be successfully transferred from the behavior used during training to a new behavior in a subsequent test phase. This result shows unambiguously that during operant conditioning classical (CS-US) associations can be formed. In an extension to this insight, it emerges that such a classical association blocks the formation of an operant association, which would have been formed without the operant control of the learned stimuli. Instead the operant component seems to develop less markedly and is probably merged into a complex three-way association. This three-way association could either be implemented as a sequential B-CS-US or as a hierarchical (B-CS)-US association. The comparison of a simple classical (CS-US) with a composite operant (B, CS and US) learning situation and of a simple operant (B-US) with another composite operant (B, CS and US) learning situation, suggests a hierarchy of predictors of reinforcement. Operant behavior occurring during composite operant conditioning is hardly conditioned at all. The associability of classical stimuli that bear no relation to the behavior of the animal is of an intermediate value, as is operant behavior alone. Stimuli that are controlled by operant behavior accrue associative strength most easily. If several stimuli are available as potential predictors, again the question arises which CS-US associations are formed? A number of different studies in vertebrates yielded amazingly congruent results. These results inspired to examine and compare the properties of the CS-US association in a complex learning situation at the flight simulator with these vertebrate results. It is shown for the first time that Drosophila can learn compound stimuli and recall the individual components independently and in similar proportions. The attempt to obtain second-order conditioning with these stimuli, yielded a relatively small effect. In comparison with vertebrate data, blocking and sensory preconditioning experiments produced conforming as well as dissenting results. While no blocking could be found, a sound sensory preconditioning effect was obtained. Possible reasons for the failure to find blocking are discussed and further experiments are suggested. The sensory preconditioning effect found in this study is revealed using simultaneous stimulus presentation and depends on the amount of preconditioning. It is argued that this effect is a case of 'incidental learning', where two stimuli are associated without the need of reinforcement. Finally, the implications of the results obtained in this study for the general understanding of memory formation in complex learning situations are discussed.
Neuropeptides have gained broad attraction in insect neuroscience and physiology, as new genetic tools are increasingly uncovering their wide-ranging pleiotropic functions with high cellular resolution. Allatostatin A (AstA) peptides constitute one of the best studied insect neuropeptide families. In insects and other panarthropods, AstA peptides qualify as brain-gut peptides and have regained attention with the discovery of their role in regulating feeding, growth, activity/sleep and learning. AstA receptor homologs are found throughout the protostomia and group with vertebrate somatostatin/galanin/kisspeptin receptors. In this review, we summarise the current knowledge on the evolution and the pleiotropic and cell-specific non-allatostatic functions of AstA. We speculate about the core functions of AstA signalling, and derive open questions and challengesfor future research on AstA and invertebrate neuropeptides in general.
Affective and cognitive behavior in the alpha-galactosidase A deficient mouse model of Fabry disease
(2017)
Fabry disease is an X-linked inherited lysosomal storage disorder with intracellular accumulation of globotriaosylceramide (Gb3) due to α-galactosidase A (α-Gal A) deficiency. Fabry patients frequently report of anxiety, depression, and impaired cognitive function. We characterized affective and cognitive phenotype of male mice with α-Gal A deficiency (Fabry KO) and compared results with those of age-matched male wildtype (WT) littermates. Young (3 months) and old (≥ 18 months) mice were tested in the naïve state and after i.pl. injection of complete Freund`s adjuvant (CFA) as an inflammatory pain model. We used the elevated plus maze (EPM), the light-dark box (LDB) and the open field test (OF) to investigate anxiety-like behavior. The forced swim test (FST) and Morris water maze (MWM) were applied to assess depressive-like and learning behavior. The EPM test revealed no intergroup difference for anxiety-like behavior in naïve young and old Fabry KO mice compared to WT littermates, except for longer time spent in open arms of the EPM for young WT mice compared to young Fabry KO mice (p<0.05). After CFA injection, young Fabry KO mice showed increased anxiety-like behavior compared to young WT littermates (p<0.05) and naïve young Fabry KO mice (p<0.05) in the EPM as reflected by shorter time spent in EPM open arms. There were no relevant differences in the LDB and the OF test, except for longer time spent in the center zone of the OF by young WT mice compared to young Fabry KO mice (p<0.05). Complementary to this, depression-like and learning behavior were not different between genotypes and age-groups, except for the expectedly lower memory performance in older age-groups compared to young mice. Our results indicate that genetic influences on affective and cognitive symptoms in FD may be of subordinate relevance, drawing attention to potential influences of environmental and epigenetic factors.
The purpose of this study was to evaluate whether spatial hippocampus-dependent learning is affected by the serotonergic system and stress. Therefore, 5-HTT knockout (-/-), heterozygous (+/-) and wildtype (+/+) mice were subjected to the Barnes maze (BM) and the Morris water maze (WM), the latter being discussed as more aversive. Additionally, immediate early gene (IEG) expression, hippocampal adult neurogenesis (aN), and blood plasma corticosterone were analyzed.
While the performance of 5-HTT-/- mice in the BM was undistinguishable from both other genotypes, they performed worse in the WM. However, in the course of the repeated WM trials 5-HTT-/- mice advanced to wildtype level. The experience of a single trial of either the WM or the BM resulted in increased plasma corticosterone levels in all genotypes. After several trials 5-HTT-/- mice exhibited higher corticosterone concentrations compared with both other genotypes in both tests. Corticosterone levels were highest in 5-HTT-/- mice tested in the WM indicating greater aversiveness of the WM and a greater stress sensitivity of 5-HTT deficient mice.
Quantitative immunohistochemistry in the hippocampus revealed increased cell counts positive for the IEG products cFos and Arc as well as for proliferation marker Ki67 and immature neuron marker NeuroD in 5-HTT-/- mice compared to 5-HTT+/+ mice, irrespective of the test. Most differences were found in the suprapyramidal blade of the dentate gyrus of the septal hippocampus. Ki67-immunohistochemistry revealed a genotype x environment interaction with 5-HTT genotype differences in naïve controls and WM experience exclusively yielding more Ki67-positive cells in 5-HTT+/+ mice. Moreover, in 5-HTT-/- mice we demonstrate that learning performance correlates with the extent of aN.
Overall, higher baseline IEG expression and increased an in the hippocampus of 5-HTT-/- mice together with increased stress sensitivity may constitute the neurobiological correlate of raised alertness, possibly impeding optimal learning performance in the more stressful WM.