The neural correlates of action–perception circuits in schizophrenia: Impaired perception of the multisensory consequences of one’s own actions
Schizophrenia is a severe mental disorder that affects approximately 1% of the population. Core symptoms include distortions in perception manifesting as auditory hallucinations and passivity phenomena (ego-disturbances). These symptoms are thought to be – at least in part – the result of an efference copy failure leading to a dysfunctional action–perception coupling. Thus, patients have difficulty accurately identifying the cause of sensory stimuli as being produced by themselves or by other causes. In a natural context, these predictions are complex, since actions usually have consequences in more than one modality (e.g. audition or vision) and are often performed with tools, where the coupling between an action and its consequence is loosened. However, little is known about the neural correlates of supramodal predictions of the consequences of our own actions, especially in a tool-use context. Therefore, the goal of this project is to investigate the neural correlates of the perception of the visual and auditory consequences of one’s own manual and tool-use actions in healthy subjects and patients with and without hallucinations and/or passivity phenomena.
The project is structured in three work packages (WP). Each WP will involve schizophrenia patients with hallucinations and/or passivity phenomena, patients without these symptoms and healthy participants. The fMRI investigations will focus on the neural correlates of supramodal action-sensory feedback matching processes (WP1), action effects on the perception of multisensory action consequences, such as sensory suppression (WP2), and predictive mechanisms for tool-use actions and related multisensory consequences (WP3). In all WPs, the subjects will perform hand movements, which are filmed by video camera. Each movement will be coupled with a tone, and both the movement and tone will be fed back to the subject digitally via headphones and a video screen. In each WP, specific tasks, feedback transformations and parametrically increasing temporal delays between the executed action and the perceived auditory-visual (i.e. multisensory) feedback will be used.
It is expected that predictions of the audio/visual sensory consequences of one’s own actions are generally disturbed in patients with schizophrenia, especially if hallucinations and/or passivity phenomena are present. It is hypothesized that the posterior superior temporal sulcus and posterior parietal cortex form a supramodal neural network, which is dysactivated in patients with relevant symptoms (WP1). In WP2, the reduced down-regulation of primary sensory cortical areas for the perception of ‘own’ in contrast to ‘other’ movements is expected. In WP3, reduced fronto-parietal activation is anticipated for the processing of one’s own tool-use consequences in patients.
These projects will help us better understand the pathophysiology of core symptoms and their neural network dysfunctions in patients with schizophrenia.
Who’s working on PACT-SZ?
Principal investigator: Benjamin Straube
PhD student: Lukas Uhlmann
Associated Postdoc: Bianca van Kemenade
Cooperations regarding action and perception
van Kemenade, B. M., Kircher, T., Arikan, B. E., & Straube, B. (2016). Predicting the sensory consequences of one’s own action: First evidence for multisensory facilitation. Attention, Perception, & Psychophysics. http://doi.org/10.3758/s13414-016-1189-1
Straube, B., Green, A., Sass, K., & Kircher, T. (2014). Superior Temporal Sulcus Disconnectivity During Processing of Metaphoric Gestures in Schizophrenia. Schizophrenia Bulletin, 40(4), 936–944. http://doi.org/10.1093/schbul/sbt110