Differential engagement of brain regions within a 'core' network during scene construction.
Reliving past events and imagining potential future events engages a well-established "core" network of brain areas. How the brain constructs, or reconstructs, these experiences or scenes has been debated extensively in the literature, but remains poorly understood. Here we designed a novel task to investigate this (re)constructive process by directly exploring how naturalistic scenes are built up from their individual elements. We "slowed-down" the construction process through the use of auditorily presented phrases describing single scene elements in a serial manner. Participants were required to integrate these elements (ranging from three to six in number) together in their imagination to form a naturalistic scene. We identified three distinct sub-networks of brain areas, each with different fMRI BOLD response profiles, favouring specific points in the scene construction process. Areas including the hippocampus and retrosplenial cortex had a biphasic profile, activating when a single scene element was imagined and when 3 elements were combined together; regions including the intra-parietal sulcus and angular gyrus steadily increased activity from 1 to 3 elements; while activity in areas such as lateral prefrontal cortex was observed from the second element onwards. Activity in these sub-networks did not increase further when integrating more than three elements. Participants confirmed that three elements were sufficient to construct a coherent and vivid scene, and once this was achieved, the addition of further elements only involved maintenance or small changes to that established scene. This task offers a potentially useful tool for breaking down scene construction, a process that may be key to a range of cognitive functions such as episodic memory, future thinking and navigation.
Summerfield
Jennifer J
JJ
Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, UK.
Hassabis
Demis
D
Maguire
Eleanor A
EA
D000328:Adult; D001921:Brain / Q000033:anatomy & histology*; D004777:Environment; D005260:Female; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D009483:Neuropsychological Tests; D014796:Visual Perception