Humans integrate stimuli from different sensory systems into a coherent and reliable representation of the environment. Yet, the human brain only integrates the stimuli, weighted proportional to their sensory reliability, if a small spatial and temporal disparity between the stimuli suggests a common cause of the stimuli. If large discrepancies suggest independent causes of the stimuli, the brain segregates the stimuli. Our previous and current work suggests that the dorsolateral prefrontal cortex (dlPFC) first determines the causal structure of the stimuli based on their discrepancy, and then the anterior intraparietal sulcus (aIPS) integrates the stimuli in a reliability-weighted manner in the case of a common signal source. However, this model of multisensory causal inference in cortical hierarchies has so far been little tested. In addition, schizophrenia could alter multisensory causal inference, leading for example to hallucination. In the project, we investigate where, when and how cortical hierarchies make a causal decision and integrate or segregate audiovisual stimuli. In EEG and fMRI studies in healthy volunteers and schizophrenia patients, we are investigating the role of the dlPFC in causal decisions and the aIPS in the integration of audiovisual stimuli. In a TMS study, we then investigate whether both regions also play a causal role in causal decisions and integration.
Duration of the project: 2018-2021
Psychophysical study on the influence of attention on explicit causal inferences in audiovisual perception. See the resulting DFG project MultiAttend: DFG project ‘MultiAttend’
Project duration: 2021-2022
Repeated and persistent rumination (brooding) is a major symptom of depressive disorders, while at the same time physical activity shows positive effects on depressive symptoms. In cooperation with the University of Tübingen, the project is investigating whether the positive effect of physical activity is mediated by a reduction in rumination. In an EGG study with depressive individuals, we develop a decoder that recognises ruminative states from neurophysiological EEG activity patterns. Thus, we can demonstrate how physical activity reduces rumination that we decode online from neurophysiological data.
Project duration: 2021-2025
In addition to spatial vision and hearing, humans can also spatially smell the location of external odour sources, similar to many animals (e.g. dogs). It is unclear whether humans combine spatial olfaction with spatial vision or hearing. In this psychophysical study, we investigate whether our brain integrates spatial odour stimuli (olfactory stimuli) with auditory spatial stimuli. The project is funded by the Special Fund for Scientific Work at FAU.
Project duration: 2023-2024