The neural correlates of action-perception coupling in schizophrenia: Impaired recalibration and cross-modal transfer of forward model predictions

• Applicant: Professor Benjamin Straube, Ph.D.
• Subject Area: Clinical Psychiatry, Psychotherapy, Child and Adolescent Psychiatry ; Human Cognitive and Systems Neuroscience
• Term: since 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 286893149

Schizophrenia is a severe mental disorder with perceptual disturbances such as auditory hallucinations and passivity phenomena (ego-disturbances). These symptoms are thought to be, at least in part, the result of efference copy failures. In the ongoing funding period, we investigate whether patients demonstrate 1) an impaired prediction of the sensory action consequences, 2) a reduced neural self-other differentiation and 3) a reduced fronto-parietal activation for the processing of tool-use action consequences. Preliminary results from the three experiments provide evidence for the expected impairments in action-perception coupling processes and their neural correlates in patients. To date, we have collected more than 160 datasets across three experiments (including 83 datasets from patients; approximately 27 datasets per experiment and group). The final sample size will be achieved by the end of the funding period. In collaboration with the SFB/TRR 135, we have developed a worldwide unique MR-compatible passive movement device (PMD) and a digital high-speed setup for audio-visual feedback, which has been the basis for numerous successful investigations. Although the preliminary results support our hypothesis of impaired action-feedback processing in patients, we cannot rule out that an impairment in temporal recalibration (i.e., adaptation to sensorimotor delays) contributes to dysfunctional action-perception coupling in schizophrenia. Thus, this phenomenon will be the focus of the new project. Each of the three new work packages (WPs) will involve 24 patients with hallucinations and / or passivity phenomena, 24 patients without these symptoms and 24 healthy participants. Two WPs will focus on fMRI to investigate the neural correlates of temporal recalibration (WP1) and cross-modal transfer of recalibration effects (WP2). In WP3, transcranial direct current stimulation (tDCS) will be used to improve the processing of action-perception coupling in patients. In all WPs, subjects will perform hand movements actively or passively using the PMD, thereby eliciting visual or auditory action feedback. To induce recalibration, the sensory feedback will be delayed in the adaptation blocks. In the test blocks, the detection of delays will be assessed. It is expected that 1) impairments in patients are, at least in part, based on insufficient recalibration of predictions within the cerebellum, 2) recalibration dysfunctions are particularly disturbing in a multisensory context and 3) cerebellar tDCS can be used to improve predictive mechanisms. In line with the translational neuroimaging approach, these projects aim at translating basic findings of previous neuroimaging research into a potential therapeutic treatment, thereby improving the action-perception coupling in patients.

• DFG Programme: Research Grants