|Beitragstitel||The cognitive and sensorimotor brain mechanisms of thought insertion|
Background: Thought insertion (TI) is defined as the subjective feeling of experiencing someone else’s thoughts in one’s own mind, those thoughts having been created and inserted into one’s mind by an external agent (Mullins and Spence 2014). Two fundamental features are considered to play a role in TI: (1) a negative aspect described as a loss of thought agency and/or ownership, putatively caused by impairments in self-monitoring and (2) a positive aspect described as the involvement of an external entity that could be due to alienation mechanisms involved in presence hallucination (PH) phenomena.
Objective: Here we aimed at understanding possible mechanisms accounting for TI by linking negative and positive aspects of the TI.
Methods: We performed a self-attenuation experiment in the cognitive domain, by comparing the numerosity estimations of self-generated and externally-generated words in 42 early psychosis patient with (n=21) or without (n=21) TI symptoms and 18 healthy controls (CTRL). We hypothesized that self-attenuation would be specifically reduced in TI+ group. We analyzed functional connectivity within the PH-network in rsfMRI.
Results: All three (TI+, TI- and CTRL) groups had a general tendency to underestimate the number of words during the active condition, with a significant difference between the active vs. passive conditions, but no significant differences between the three groups tested. Attenuation for self-generated signal was negatively correlated to the decreased executive functioning only in TI+ patients. We have observed reduced connectivity between fronto-temporal areas and temporal areas but increased connectivity between frontal areas within PH-network in TI+ patients. Lastly, we’ve linked these two aspects by showing that increased connectivity in TI+ patients between frontal areas is positively correlated to the varying levels of cognitive self-attenuation.
Conclusion: We have shown that attenuation can be observed for higher-level cognitive processes such as numerosity estimations. The observed link between the executive functioning and attenuation during numerosity estimations suggest that the TI phenomenon is related to the deficits in higher-level cognition. Increased functional connectivity in frontal PH-network could reflect altered cognitive functioning.