Using choir conducting to improve leadership practice

fi=vertaisarvioitu|en=peerReviewed

Virtual environments as memory training devices in navigational tasks for older adults.

Cognitive training approaches using virtual environments (VEs) might counter age-related visuospatial memory decline and associated difficulties in wayfinding. However, the effects of the visual design of a VE in route learning are not fully understood. Therefore, we created a custom-designed VE optimized for route learning, with adjusted levels of realism and highlighted landmark locations (MixedVE). Herein we tested participants' route recall performance in identifying direction of turn at the intersection with this MixedVE against two baseline alternatives (AbstractVE, RealisticVE). An older vs. a younger group solved the tasks in two stages (immediate vs. delayed recall by one week). Our results demonstrate that the MixedVE facilitates better recall accuracy than the other two VEs for both age groups. Importantly, this pattern persists a week later. Additionally, our older participants were mostly overconfident in their route recall performance, but the MixedVE moderated this potentially detrimental overconfidence. Before the experiment, participants clearly preferred the RealisticVE, whereas after the experiment, most of the younger, and many of the older participants, preferred the MixedVE. Taken together, our findings provide insights into the importance of tailoring visualization design in route learning with VEs. Furthermore, we demonstrate the great potential of the MixedVE and by extension, of similar VEs as memory training devices for route learning, especially for older participants

Dopamine, affordance and active inference.

The role of dopamine in behaviour and decision-making is often cast in terms of reinforcement learning and optimal decision theory. Here, we present an alternative view that frames the physiology of dopamine in terms of Bayes-optimal behaviour. In this account, dopamine controls the precision or salience of (external or internal) cues that engender action. In other words, dopamine balances bottom-up sensory information and top-down prior beliefs when making hierarchical inferences (predictions) about cues that have affordance. In this paper, we focus on the consequences of changing tonic levels of dopamine firing using simulations of cued sequential movements. Crucially, the predictions driving movements are based upon a hierarchical generative model that infers the context in which movements are made. This means that we can confuse agents by changing the context (order) in which cues are presented. These simulations provide a (Bayes-optimal) model of contextual uncertainty and set switching that can be quantified in terms of behavioural and electrophysiological responses. Furthermore, one can simulate dopaminergic lesions (by changing the precision of prediction errors) to produce pathological behaviours that are reminiscent of those seen in neurological disorders such as Parkinson's disease. We use these simulations to demonstrate how a single functional role for dopamine at the synaptic level can manifest in different ways at the behavioural level

Web navigation structures in cellular phones: The depth/breadth trade-off issue

One can browse the web with a variety of devices, including hand-held devices such as the cellular phone. The small screen of those devices poses some serious usability issues, one of which is the appropriate hierarchy depth of the web site. In this study, we empirically examined whether a broad navigation structure, which was found to be superior in regular screen-size platforms, also has an advantage for a small-screen device such as the cellular phone where it may require more movements and scrolling between screens of the same hierarchical level. Navigation times and success rates were measured for two search tasks in a mock web site that was built in two versions: one with a broad navigation structure and the other with a deep structure. Both structures were tested with cellular phone emulation and a standard desktop personal computer (PC). Results indicate that performance was better with the broad navigation structure for both the cellular phone and the PC. In addition, performance was better with the PC as compared to the cellular phone, and this difference was pronounced in the broad structure. The results are discussed in terms of the impact of device-independent characteristics of the hierarchy depth along with the theoretical account of increased working memory load, confusion and disorientation associated more with deep structures

A method for mapping and measuring users' mental models of the depth/breadth tradeoff

Understanding users' mental models can improve design and testing of interactive systems. Yet, the extraction of users' mental models and their representation are still a tough challenge. We addressed this question by focusing on how the depth/breadth tradeoff in web navigation structures is reflected in users' mental models. The approach presented here is based on gathering the data in an unlimited-hierarchy variation of card sorting technique and analyzing the results using hierarchic cluster analysis visualized with dendograms. We report a pilot study of our approach and compare the hierarchic cluster analysis and dendograms with ANOVA. The findings show significantly different perceptions of breadth versus depth in two different devices, a desktop computer and cellular phone. These findings are in contrast with findings of more traditional mental model assessment approaches, thus validating the necessity and the usefulness of the purposed new approach

A PARP1-ERK2 synergism is required for the induction of LTP.

Unexpectedly, a post-translational modification of DNA-binding proteins, initiating the cell response to single-strand DNA damage, was also required for long-term memory acquisition in a variety of learning paradigms. Our findings disclose a molecular mechanism based on PARP1-Erk synergism, which may underlie this phenomenon. A stimulation induced PARP1 binding to phosphorylated Erk2 in the chromatin of cerebral neurons caused Erk-induced PARP1 activation, rendering transcription factors and promoters of immediate early genes (IEG) accessible to PARP1-bound phosphorylated Erk2. Thus, Erk-induced PARP1 activation mediated IEG expression implicated in long-term memory. PARP1 inhibition, silencing, or genetic deletion abrogated stimulation-induced Erk-recruitment to IEG promoters, gene expression and LTP generation in hippocampal CA3-CA1-connections. Moreover, a predominant binding of PARP1 to single-strand DNA breaks, occluding its Erk binding sites, suppressed IEG expression and prevented the generation of LTP. These findings outline a PARP1-dependent mechanism required for LTP generation, which may be implicated in long-term memory acquisition and in its deterioration in senescence