title: Neural Mechanisms of Hierarchical Planning in a Virtual Subway Network.
abstract: Planning allows actions to be structured in pursuit of a future goal. However, in natural environments, planning over multiple possible future states incurs prohibitive computational costs. To represent plans efficiently, states can be clustered hierarchically into "contexts". For example, representing a journey through a subway network as a succession of individual states (stations) is more costly than encoding a sequence of contexts (lines) and context switches (line changes). Here, using functional brain imaging, we asked humans to perform a planning task in a virtual subway network. Behavioral analyses revealed that humans executed a hierarchically organized plan. Brain activity in the dorsomedial prefrontal cortex and premotor cortex scaled with the cost of hierarchical plan representation and unique neural signals in these regions signaled contexts and context switches. These results suggest that humans represent hierarchical plans using a network of caudal prefrontal structures. VIDEO ABSTRACT.
authors.affiliation: Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK; Google Deepmind, London EC4A 3TW, UK. Electronic address: jua@google.com.
authors.forename: Jan
authors.initials: J
authors.lastname: Balaguer
authors.affiliation: Department of Experimental Psychology, University College London, London WC1E 6BT, UK.
authors.forename: Hugo
authors.initials: H
authors.lastname: Spiers
authors.affiliation: Google Deepmind, London EC4A 3TW, UK.
authors.forename: Demis
authors.initials: D
authors.lastname: Hassabis
authors.affiliation: Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK; Google Deepmind, London EC4A 3TW, UK.
authors.forename: Christopher
authors.initials: C
authors.lastname: Summerfield
mesh_terms: D000328:Adult; D001519:Behavior; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D013647:Task Performance and Analysis; D055815:Young Adult