| Popis: |
Our research group investigates perception and decision making in the somatosensory domain. The focus in the last few years has been on the neural correlates of subliminal or near-threshold stimuli (Nierhaus et al.,2015) and possible moderating variables of perception such as attention (Forschack et al., 2017) and confidence (Grund et al., 2020). Another focus of our research group are heart-brain interactions. Recent work from our lab has shown that perception of weak somatosensory stimuli depends on the phase of the cardiac cycle and leads to changes in perceptual sensitivity (Al et al., 2020). A signal detection theoretic analysis further indicated that changes in the heartbeat evoked potential measured with EEG are reflected in changes in the decision criterion. Al and colleagues explained the modulation of perception and neural response along the cardiac cycle in a predictive coding framework, in which the brain is continuously producing and updating a model of sensory input. A strong prior expectation of a heartbeat likely prevents a weak somatosensory stimulus from being consciously perceived. Heartbeats may therefore act as a prior on the perception of a somatosensory stimulus. Various research groups investigated neural correlates of changes in decision criterion (Shermann et al., 2016, Rahnev, Lau & Lange, 2011). To our best knowledge there is no research on stimulus expectations and related changes in criterion in the somatosensory system. A study by Shermann et al. (2015) showed that prior expectations about stimulus probabilities changed participants decision criterion but not their perceptual sensitivity in a visual detection task. Our group showed that heartbeat evoked potentials are related to changes in decision criterion. An interesting open question is therefore, whether a manipulation of stimulus expectations is reflected in a a change in the decision criterion and modulates heartbeart-evoked potentials. An important first step towards investigating the influence of prior expectations on the heartbeat-evoked potential is the implementation of a behavioral paradigm in the somatosensory system that allows to investigate stimulus expectations and related criterion and/or sensitivity changes. |
