Lars Schwabe

The perspective from where the world is perceived is an important aspect of the bodily self and may break down in neurological conditions such as out‐of‐body experiences (OBEs). These striking disturbances are characterized by disembodiment, an external perspective and have been observed after temporoparietal damage. Using mental own body imagery, recent neuroimaging work has linked perspectival changes to the temporoparietal cortex. Because the disembodied perspective during OBEs is elevated in the majority of cases, we tested whether an elevated perspective will interfere with such temporoparietal mechanisms mental own body imagery. We designed stimuli of life‐sized humans rotated around the vertical axis and rendered as if viewed from three different perspectives: elevated, lowered, and normal. Reaction times (RTs) in an own body transformation task, but not the control condition, were dependent on the rotation angle. Furthermore, RTs were shorter for the elevated as compared with the normal or lowered perspective. Using high‐density EEG and evoked potential (EP) mapping, we found a bilateral temporoparietal and frontal activation at ≈330–420 ms after stimulus onset that was dependent on the rotation angle, but not on the perspective. This activation was also found in response‐locked EPs. In the time period ≈210–330 ms we found a temporally distinct posterior temporal activation with its duration being dependent on the perspective, but not the rotation angle. Collectively, the present findings suggest that temporoparietal and frontal as well as posterior temporal activations and their timing are crucial neuronal correlates of the bodily self as studied by mental imagery. Hum Brain Mapp, 2009.

Regenerative systems are able to overcome significant perturbations, and maintain autonomously their functionality in dynamic and uncertain environments. More and more this ability of biological systems plays a role in designing technical systems, e.g., in sensor networks, as well. Important properties of regenerative systems are their dynamic structures and their operation on different spatial and temporal scales. Those propel the development of new modeling, simulation, and visualization methods. Among them, variants of the π-calculus formalism, a portfolio of Gillespie related spatial simulation algorithms, means for automatically configuring simulators, and the integrated visualization methods, that make use of innovative layouts and linked and coordinated views target challenges in analyzing biological regenerative systems. They provide a basis for analyzing regenerative systems in general by means of simulation.

Neurological evidence suggests that disturbed vestibular processing may play a key role in triggering out-of-body experiences (OBEs). Little is known about the brain mechanisms during such pathological conditions, despite recent experimental evidence that the scientific study of such experiences may facilitate the development of neurobiological models of a crucial aspect of self-consciousness: embodied self-location. Here we apply Bayesian modeling to vestibular processing and show that OBEs and the reported illusory changes of self-location and translation can be explained as the result of a mislead Bayesian inference, in the sense that ambiguous bottom-up signals from the vestibular otholiths in the supine body position are integrated with a top-down prior for the upright body position, which we measure during natural head movements. Our findings have relevance for self-location and translation under normal conditions and suggest novel ways to induce and study experimentally both aspects of bodily self-consciousness in healthy subjects.