Biology subjects

Strube, A.

Publications and source records attributed to Strube, A..

4 recordsLinked to original sources

bioRxiv2022

Agency and Expectations in Pain Treatment: An Investigation of the Active Inference Model

The fact that we cannot tickle ourselves is traditionally explained by the attenuation of somatosensation by predictions from a forward model of self-generated movements. Alternatively, it has been suggested within the framework of active inference that Bayes-optimal reduction of sensory precision can explain this phenomenon. Combining a pain paradigm with stimulus-related expectations allows to compare both models through predictions from the Bayesian account of expectation-based hypoalgesia, where pain is influenced by the precisions of somatosensation and expectation. In two experiments, heat pain was sham-treated either externally or by the subject, while a cue created higher or lower treatment expectations. Both experiments revealed greater pain relief under self-treatment and high treatment expectations. Electroencephalography revealed a modulation of theta-to-beta frequencies linked to agency and top-down modulations of pain perception. Computational modeling showed that this is better explained by an attenuation of somatosensation than a downregulation of somatosensation precision, favoring the forward model.

neuroscience↗

bioRxiv2021

Alpha-to-beta- and gamma-band activity reflect predictive coding in affective visual processing

Processing of negative affective pictures typically leads to desynchronization of alpha-to-beta frequencies (ERD) and synchronization of gamma frequencies (ERS). Given that in predictive coding higher frequencies have been associated with prediction errors, while lower frequencies have been linked to expectations, we tested the hypothesis that alpha-to-beta ERD and gamma ERS induced by aversive pictures are associated with expectations and prediction errors, respectively. We recorded EEG while volunteers were involved in a probabilistically cued affective picture task using three different negative valences to produce expectations and prediction errors. Our data show that alpha-to-beta band activity was related to the expected valence of the stimulus as predicted by a cue. The absolute mismatch of the expected and actual valence, which denotes an absolute prediction error was related to gamma band activity. This demonstrates that top-down predictions and bottom-up prediction errors are represented in specific spectral patterns associated with affective picture processing.

neuroscience↗

bioRxiv2020

The temporal characteristics of expectations and prediction errors in pain

In the context of a generative model, such as predictive coding, pain and heat perception can be construed as the integration of expectation and input with their difference denoted as a prediction error. In a previous neuroimaging study (Geuter et al., 2017) we observed an important role of the insula in such a model, but could not establish its temporal aspects. Here we employed electroencephalography to investigate neural representations of predictions and prediction errors in heat and pain processing. Our data show that alpha-to-beta activity was associated with stimulus intensity expectation, followed by a negative modulation of gamma band activity by absolute prediction errors. This is in contrast to prediction errors in visual and auditory perception, which are associated with increased gamma band activity, but is in agreement with observations in working memory and word matching, which show gamma band activity for correct, rather than violated predictions.

neuroscience↗

bioRxiv2019

Neurophysiological correlates of collective perceptual decision-making

Humans frequently coordinate with others in daily life. A recent study on perceptual decision-making showed that dyad members with similar individual performances attain a higher joint performance than the better dyad member (i.e., a collective benefit). However, little is known about the physiological basis of these results. Here, we replicate this earlier work and also investigate the neurophysiological correlates of decision-making using EEG.\n\nIn a two interval forced choice task, co-actors individually indicated presence of a target stimulus with a higher contrast and then indicated their confidence on a rating scale. Viewing the individual ratings, dyads made a joint decision. Replicating earlier work, we found a positive correlation between the similarity of individual performances and collective benefit.\n\nWe analyzed event related potentials (ERPs) in three phases (i.e., stimulus onset, response, and feedback) using explorative cluster mass permutation tests. At stimulus onset, ERPs were significantly linearly related to our manipulation of contrast differences, validating our manipulation of task difficulty. For individual and joint responses, we found a significant centro-parietal error-related positivity for correct versus incorrect responses, which suggests that accuracy is already evaluated at the response level. At feedback presentation, we found a significant late positive fronto-central potential elicited by incorrect joint responses, suggesting a stronger emotional response to negative as compared to positive feedback. In sum, these results demonstrate that response- and feedback-related components elicited by an error-monitoring system differentially integrate conflicting information exchanged during the joint decision-making process.

neuroscience↗