During the implementation of the project, we advanced existing approaches and developed novel methodologies in several domains, including (1) multisensory stimulus paradigms, (2) sensory augmentation techniques, (3) methods for neurostimulation, (4) methods for removal of artefacts resulting from eye movements or electrical stimulation, (5) methods for analysis of neural connectivity in EEG or MEG data, as well as (6) methods for analysis of BCI signals. Furthermore, our work contributes (7) to open-source data repositories and (8) to internet-based study methodologies.
(1) In the investigation of multimodal integration we developed an innovative joint search and interaction paradigm. This has been further developed incorporating the experience on the dual task design involving multiple object tracking. This has lead to an experimental design for systematic investigation of sensory integration and communication in a collaborative task setting. It forms the fundament of an upcoming series of experiments on the neurophysiology of joint action. Furthermore, we developed a novel paradigm involving crossmodal matching of changes in stimulus amplitudes, which we first used in bimodal versions and subsequently extended to include simultaneous stimulation of vision, audition, and somatosensation.
(2) Testing predictions of sensorimotor contingency theory we developed a new device for sensory augmentation. It mediates information on the orientation of the body relative to magnetic north by tactile signals. We investigated behavioural, physiological and perceptual changes in a longitudinal study. These scientific developments have led to the founding of a spin-off company (feelSpace GmbH).
(3) In studies using transcranial alternating current stimulation (tACS) we improved the spatial resolution of the stimulation and developed novel approaches for removing stimulation artefacts from concurrent EEG recordings. This enabled us to study immediate electrophysiological effects during the frequency-specific entrainment of oscillatory signatures. In one study we could demonstrate that 10 Hz tACS increases parieto-occipital alpha activity and synchronizes cortical oscillators with similar intrinsic frequencies to the entrainment frequency. Additionally, we could demonstrate that tACS modulates target detection performance in a phase-dependent fashion highlighting the causal role of alpha oscillations for visual perception. In a second study we could show that interhemispheric functional connectivity was modulated by gamma-band tACS in a predictable, phase-specific way: In-phase stimulation enhanced synchronization, anti-phase stimulation impaired functional coupling. These findings provide causal evidence for physiological roles of neural oscillations in the parieto-occipital cortex.
(4) In several studies we improved techniques for removing eye movement artefacts, which enabled us to investigate brain signals using EEG or MEG while subjects were carrying out saccadic eye movements.
(5) For advancing possibilites to analyse neural coupling in noninvasive data, we further developed methods for analysis of coupling that circumvent the problem of source mixing due to volume conductions and implemented novel approaches for the analysis of cross-frequency coupling. Furthermore, we developed a more rigorous theoretical perspective on the relation between phase and envelope coupling.
(6) Additional technological developments in the project aimed at improvement of BCI information transfer for steady-state brain-computer interfaces. This could be achieved by using frequency and phase coding for classification, and by modifying control modes enabling fast feedback and fast input.
(7) The studies on visual explorative behaviour listed above contribute a large part of the Osnabrück-Hamburg eye-tracking database. This well documented and publicly accessible database collects a total of 26 studies and thereby presents an order of magnitude larger collection of data than previously available. These were collected by systematically trained personnel and with homogeneous setups and thus presents a valuable resource for future research in this field.
(8) We pushed internet technologies for the study of spatial navigation. In an online study with more than 2000 participants world wide we investigated an characterised spatial navigation based on visual cues. Based on this experience SciCovery was founded as a spin-off company of the University Osnabrück in early 2017 which translates these research results.