Dr Nadja Tschentscher | The neural basis of abstract reasoning, as revealed by fMRI and EEG/MEG

Abstract reasoning relies on a sequence of cognitive steps involving phases of task encoding, the structuring of solution steps, and their execution. On the neural level, metabolic neuroimaging studies have associated a distributed cognitive control or multiple-demand (MD) network with various aspects of abstract reasoning, and lesions within this network have been highly predictive for loss of fluid intelligence. By means of fMRI, I have specified the link between MD functions and fluid intelligence: low fluid intelligence has been associated with poor foregrounding of task-critical information across the MD system, accompanied by impaired performance. A second line of my research concerns the millisecond-by-millisecond neural dynamics in MD cortices. Evoked EEG-MEG source analyses revealed independent activation dynamics in frontal and parietal cortices within the first second of an abstract reasoning process. Oscillatory source power analyses allowed dissociating the memory and executive control functions underlying differential reasoning strategies. Together, my multi-method neuroimaging approach has provided insights into the anatomical, spatio-temporal, and oscillatory neural signatures of human abstract reasoning and fluid intelligence.