Consciousness in a multilevel architecture: Evidence from the right side of the brain.

The brain's resting-state interactions show a general rightward and top-down bias in excitatory connections among structures from different evolutionary layers (archicortex, paleocortex, neocortex), based on fMRI data from 25 healthy subjects. The right hippocampus uniquely exerts bottom-up excitatory influence reaching the frontopolar cortex, while the right ventrolateral cortex interacts with most nodes across evolutionary subdivisions. These findings suggest multiple levels of cognitive-affective organization in the human brain with profound lateralization.

Study at a glance

Abstract

By taking into account Bruce Bridgeman's interest in an evolutionary framing of human cognition, we examine effective (cause-and-effect) connectivity among cortical structures related to different parts of the triune phylogenetic stratification: archicortex, paleocortex and neocortex. Using resting-state functional magnetic resonance imaging data from 25 healthy subjects and spectral Dynamic Causal Modeling, we report interactions among 10 symmetrical left and right brain areas. Our results testify to general rightward and top-down biases in excitatory interactions of these structures during resting state, when self-related contemplation prevails over more objectified conceptual thinking. The right hippocampus is the only structure that shows bottom-up excitatory influences extending to the frontopolar cortex. The right ventrolateral cortex also plays a prominent role as it interacts with the majority of nodes within and between evolutionary distinct brain subdivisions. These results suggest the existence of several levels of cognitive-affective organization in the human brain and their profound lateralization.