Brain mechanisms associated with internally directed attention and self-generated thought

TLDR

Internal cognition such as imagination and prospection relies on sustained internally directed attention and self‑generated thought. This fMRI study aimed to separate brain mechanisms underlying attention‑specific versus task‑specific processes during internally directed cognition. Participants performed tasks with attention directed either by keeping a stimulus visible or by masking it, while self‑directed thought was manipulated between convergent and divergent thinking. Internally directed attention activated the right anterior inferior parietal lobe, bilateral lingual gyrus, and cuneus, while deactivating dorsal attention network regions, and the right aIPL’s increased connectivity with occipital cortex suggests top‑down shielding; default network activity correlated with self‑generated thought, highlighting distinct roles for inferior and superior parietal cortex.

Abstract

Internal cognition like imagination and prospection require sustained internally directed attention and involve self-generated thought. This fMRI study aimed to disentangle the brain mechanisms associated with attention-specific and task-specific processes during internally directed cognition. The direction of attention was manipulated by either keeping a relevant stimulus visible throughout the task, or by masking it, so that the task had to be performed "in the mind's eye". The level of self-directed thought was additionally varied between a convergent and a divergent thinking task. Internally directed attention was associated with increased activation in the right anterior inferior parietal lobe (aIPL), bilateral lingual gyrus and the cuneus, as well as with extended deactivations of superior parietal and occipital regions representing parts of the dorsal attention network. The right aIPL further showed increased connectivity with occipital regions suggesting an active top-down mechanism for shielding ongoing internal processes from potentially distracting sensory stimulation in terms of perceptual decoupling. Activation of the default network was not related to internally directed attention per se, but rather to a higher level of self-generated thought. The findings hence shed further light on the roles of inferior and superior parietal cortex for internally directed cognition.