Decoding the Human Brain during Intelligence Testing

Understanding the mechanisms of the human brain enabling complex cognition is a major objective of neuroscientific research. Studies employing functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) identified increased activation in specific brain regions during different cognitive states. However, the neural processes during the performance of an intelligence test remains largely unknown. This study considers intelligence as a whole-brain network phenomenon and investigates how the connectedness of specific brain regions contributes to performance on the Raven Progressive Matrices (RAPM), a well-established intelligence test. Connectedness was characterized with graph-theoretical measures based on functional connectivity derived from fMRI BOLD ( N =67) and EEG theta-band ( N =128) activity. The results reveal that the extent to which specific frontal and parietal regions are connected to other brain systems during intelligence testing relates to individual test performance. These regions may act as controllers, enabling flexible and efficient switches between cognitive states required to excel in intelligence tests.