Mapping the Interaction between Semantic Representation and Control Systems: The Controlled Semantic Cognition

ended

"People, places and things have ""meaning"" that we use to know who/what they are and what we can do with them. Our ability to use that knowledge –our ""Semantic Cognition""– is essential for making sense of what we see, enabling us to interact appropriately with the world. This important ability depends on two separate brain systems: the system of representations that encodes our conceptual knowledge and the system of control that manipulates activation within the representational system, generating appropriated behaviours. However, we do not yet know how the two systems interact. A fuller understanding of the semantic cognition depends on us uncovering this relationship in healthy behaviours and to know how is reshaped after brain damage/disruption. A joint account of both subsystems has been recently proposed by my supervisor: the Controlled Semantic Cognition (CSC). The key goal of this project is the neural computational modelling of the CSC and its disorders. I will model both semantic subsystems jointly for the first time by testing one healthy group and two patient groups with dissociated semantic disorders: semantic dementia (impaired in semantic representations); and semantic aphasia (impaired in semantic control). I will use different neuroimaging techniques such as DWMRI, fMRI and TMS in combination with the comparison between healthy controls and patients to model the dynamical causal networks, cross-validate the models and pinpoint the interactions between the semantic subnetworks, understanding how and under what circumstances they recruit each other. Our results will bring insights into how the brain manipulates information that gives rise semantic behaviours, advancing knowledge about a critical part of the human experience. Also in the implementation of methods for multimodal neuroimaging integration in the study of dynamics and plasticity in highly-distributed cognitive systems, such as CSC, in healthy and dysfunctional brains."