Thesis defense Marius Braunsdorf (Donders Series 604)

19 April 2023

Promotor: prof. dr. Harold Bekkering
Copromotor: dr. Rogier B. Mars

The temporal lobe and medial wall in social cognition: computations and organisation

Social cognition is a particularly well and uniquely developed faculty in humans. In this thesis we investigated the cognitive computational implementation in the brain and anatomical organization of the temporal lobe and medial wall. For the first part of the thesis we conducted two fMRI studies, investigating computational aspects underlying social decision making. First, we developed a task in which participant accumulate diverging knowledge about the world between the participant and a confederate. We successfully dissociated the context (‘self’ vs. ‘other’) of a decision in the medial wall and the underlying evidence accumulation (‘shared’ vs. ‘privileged’) in the temporo-parietal junction. We also developed a task focusing on the behavior of the other by investigating successful communication in the face of bias confederates. We found neural correlates of relevant social decision parameters in the temporo-parietal junction, and large parts of the medial prefrontal cortex. For the second part of the thesis, we investigated the organization of the temporal lobe and medial wall. We first conducted a review of the literature placing the primate temporal lobe in an evolutionary context. We concluded significant reorganization and expansion beyond what can be expected due to increased brain size, enabling humans to more elaborate categorization, semantic and social abilities. We further conducted a quantitative analysis of the temporal lobe’s graded organization across meta-analytic task maps finding a close resemblance between structural and functional organization. We also found 2 dimensions relating to how social cognition is organized in the temporal lobe and the medial wall indicating a selective preference relating to timescale with which relevant information needs to be retained. This thesis contributed to the field of social cognitive neuroscience with a better understanding of social cognitive computations and their implementation in the brain. Furthermore, we propose a multidimensional theory of organization of the temporal lobe and generated an understanding of differences in social cognitive organization between the medial wall and the temporal lobe.