Behavioral and neural correlates of updating and its relationship with Theory of Mind

We hypothesize that the ability to update mental representations is crucial for many cognitive functions. A damage to the updating system can explain many of the heterogeneous impairments seen after right brain damage (RBD), including impaired Theory of Mind (ToM). Hence, it is crucial to understand the behavioral and neural correlates of updating and how updating and ToM are related to optimise treatment and rehabilitation strategies. Background: To survive in a complex and constantly changing environment we have to categorize the world (e.g., Is that animal dangerous or not?) and we need to update those representations when things change. We have previously developed a quick and easy task to measure updating: in different picture sets a commonly known object (e.g., rabbit) morphed into a completely different object (e.g., duck). We demonstrated that RBD participants required significantly more pictures to change their reports, demonstrating an updating impairment after RBD. Lesion overlay analysis of our patient data, as well as an fMRI study, revealed involvement of the anterior insula in updating. Other studies have showed that the anterior insula is related to ToM impairments in RBD patients and that this region is hypoactive in people with Autism Spectrum Disorder (ASD) indicating that the anterior insula is an important hub for both updating and ToM. Additionally, in 5 year olds we demonstrated that the ability to update mental representations plays a key role in ToM. Goal 1 will enhance an understanding of the different components of updating: Goal (1a) will investigate the different neural networks involved in each of the following updating components (change detection, decision under uncertainty, exploration). Goal (1b) will test if a failure to explore can account for the updating impairment of RBD patients. Goal (1c) will investigate how the ability to explore changes with age in adult participants. Goal 2 will enhance an understanding why ToM and Updating are connected. Goal (2a) we will explore if the connection between ToM and Updating is due to the fact that both tasks rely on the understanding of their own false beliefs or due to a joint need to reorient attention. Goal (2b) will evaluate if either a failure to explore or an immature perceptual system can account for the fact that even the best performing 5 year old children still update at the same level as RBD patients. Goal (2c) will extract the neural correlates of each updating subcomponent and compare it to the neural correlates associated with ToM. This will shed light on the exact nature of the shared network and consequently on the exact nature of the involved cognitive mechanism.

To survive in a complex, noisy and constantly changing environment we have to categorize the world (e.g., Is an animal dangerous or not? Is a food edible or not?). Even more importantly, we need to update our assumptions about the world when things change. We measure this updating process by using a picture morphing task (https://osf.io/qi2vg/) in which objects (e.g., a rabbit) gradually morphing into another (e.g., a duck). The idea is that the longer it takes a person before they report seeing the second object, the harder a time they have with updating. We demonstrated that healthy participants see the second object earlier when pictures are presented in a gradually morphing context than when the same pictures are presented on their own. For example 87% reported "pear" in the violin-pear picture set at the ambiguous middle image, while only 56% did so when they saw the same picture outside of the morphing context. This suggests that healthy individuals are using active search strategies (e.g., "I know it was a violin but what else could it be?). Presenting participants with this task in the MRI scanner revealed a distributed network at the moment of change - with the anterior insula not only active at the moment of change but also 5 seconds before - possibly reflecting the need to explore alternative interpretations. We demonstrated that damage to the right hemisphere - especially the right anterior insula -selectively impaired updating. Right brain damaged (RBD) participants needed significantly more pictures compared to left brain damaged (LBD) patients and healthy seniors (HCO) before they recognized the second object. Other than HCO and LBD patients, RBD patients were hindered by the gradually morphing context. Interestingly, we found very similar results in 3 to 8 year old children. That is, while healthy adults benefit from a gradual presentation, children and RBD patients are hindered by it. Preliminary data in children suggest that children use a completely different exploration style compared to healthy adults. We assume that they focus far too much on small details (e.g., the rabbit's ears getting smaller) at the expense of noticing the bigger picture (e.g., the rabbit turning into a duck).