title: A new role for the parahippocampal cortex in representing space.
abstract: The debate surrounding the function of the human posterior parahippocampal cortex (PHC) is currently dominated by two competing theories. The spatial layout hypothesis proposes that PHC processes information about the shape of space embodied in layout-defining scene features. The contextual association hypothesis rejects this notion, proposing instead that PHC responds to highly contextualized, but not necessarily spatial, stimuli. Here we present a novel concept that suggests PHC is primarily concerned with any representation that depicts three-dimensional local space, be it scenes or even single objects. Specifically, we identified space-defining (SD) and space-ambiguous (SA) single objects, where SD objects consistently evoke a strong sense of the surrounding space while SA objects do not, in the absence of any background, spatial layout, or context. We found that participants could easily identify and distinguish between SD and SA objects. This distinction was subsequently affirmed at a neural level, where visualizing or viewing single SD objects compared with SA objects engaged PHC, despite these single SD objects offering no information about the shape or layout of the space. Moreover, this PHC response was robust and not accounted for by other factors, including contextual associations. Instead, it was linked to intrinsic object properties, specifically a combination of perceived object size and portability. By showing that PHC is responsive to the awareness of surrounding local space suggests its role in scene processing is basic and fundamental, such that it is not dependent on complex scene properties such as geometric structure, scene schema, or contextual associations.
authors: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
authors: Sinéad L
authors: SL
authors: Mullally
authors: Eleanor A
authors: EA
authors: Maguire
references: Nat Rev Neurosci. 2009 Nov;10(11):792-802
references: 19812579
references: Trends Cogn Sci. 2007 Jul;11(7):299-306
references: 17548229
references: Nat Neurosci. 2004 Jun;7(6):673-7
references: 15146191
references: Behav Brain Funct. 2008 Aug 15;4:38
references: 18706088
references: Neuroimage. 2009 Oct 1;47(4):1747-56
references: 19398014
references: Cereb Cortex. 2010 Feb;20(2):294-303
references: 19457939
references: Philos Trans R Soc Lond B Biol Sci. 2009 May 12;364(1521):1263-71
references: 19528007
references: J Cogn Neurosci. 2009 Mar;21(3):489-510
references: 18510452
references: Neuron. 2003 Apr 24;38(2):347-58
references: 12718867
references: Trends Cogn Sci. 2008 Oct;12(10):388-96
references: 18760955
references: J Neurosci. 2007 Dec 26;27(52):14365-74
references: 18160644
references: Neuron. 1999 May;23(1):115-25
references: 10402198
references: Neuropsychologia. 2003;41(10):1387-95
references: 12757910
references: J Neurosci. 2008 Aug 20;28(34):8539-44
references: 18716212
references: J Exp Psychol Hum Learn. 1976 Jan;2(1):38-48
references: 1249532
references: J Cogn Neurosci. 2000 Nov;12(6):1013-23
references: 11177421
references: Annu Rev Psychol. 1999;50:243-71
references: 10074679
references: Perception. 1996;25(3):343-52
references: 8804097
references: Brain Cogn. 2008 Feb;66(1):40-9
references: 17606317
references: Nature. 1998 Apr 9;392(6676):598-601
references: 9560155
references: Brain. 1999 Sep;122 ( Pt 9):1613-28
references: 10468502
references: Neuropsychologia. 2010 Apr;48(5):1501-9
references: 20132831
references: Neuroimage. 2001 Apr;13(4):743-50
references: 11305901
references: Cogn Psychol. 1982 Apr;14(2):143-77
references: 7083801
references: Nat Rev Neurosci. 2004 Aug;5(8):617-29
references: 15263892