Human cognitive functions, including visual working memory, are subjectively coherent, such that we memorize coherent images not their components, of prior events. However neuronal processing underlying working memory takes place concurrently in many brain areas in which brain rhythms - oscillations- in many frequencies are ubiquitous and characterize processing. Fast oscillatory synchronization is thought to integrate the processing of visual information in the visual system of the brain whereas slower oscillatory synchronization is thought to coordinate executive functions in the frontal and parietal brain areas.
– A key challenge has been to understand which mechanisms integrate neuronal processing across fast and slow oscillatory networks and thereby the sensory and executive functions, explains Palva.
Using concurrent magneto- and electroencephalography (MEG and EEG), Palva’s group found a novel mechanism that can connect fast and slow oscillatory networks. During visual working memory, fast and slow oscillatory networks in sensory and frontoparietal brain areas became connected via cross-frequency phase synchronization.
– Our finding may explain how processing between distinct brain rhythms carrying out distinct computational functions may be integrated, summarizes Satu Palva.