title: Prior knowledge of illumination for 3D perception in the human brain.
abstract: In perceiving 3D shape from ambiguous shading patterns, humans use the prior knowledge that the light is located above their head and slightly to the left. Although this observation has fascinated scientists and artists for a long time, the neural basis of this "light from above left" preference for the interpretation of 3D shape remains largely unexplored. Combining behavioral and functional MRI measurements coupled with multivoxel pattern analysis, we show that activations in early visual areas predict best the light source direction irrespective of the perceived shape, but activations in higher occipitotemporal and parietal areas predict better the perceived 3D shape irrespective of the light direction. These findings demonstrate that illumination is processed earlier than the representation of 3D shape in the visual system. In contrast to previous suggestions, we propose that prior knowledge about illumination is processed in a bottom-up manner and influences the interpretation of 3D structure at higher stages of processing.
authors.affiliation: School of Psychology, University of Birmingham, Birmingham B15 2TT, United Kingdom.
authors.forename: Peggy
authors.initials: P
authors.lastname: Gerardin
authors.forename: Zoe
authors.initials: Z
authors.lastname: Kourtzi
authors.forename: Pascal
authors.initials: P
authors.lastname: Mamassian
mesh_terms: D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D006801:Humans; D021621:Imaging, Three-Dimensional; D008029:Lighting; D008279:Magnetic Resonance Imaging; D014796:Visual Perception
references.citation: Nat Neurosci. 2005 May;8(5):686-91
references.pmid: 15852013
references.citation: Nature. 1988 Jan 14;331(6152):163-6
references.pmid: 3340162
references.citation: Nat Neurosci. 2006 Apr;9(4):578-85
references.pmid: 16547513
references.citation: Neuroreport. 2003 May 23;14(7):971-5
references.pmid: 12802185
references.citation: Nat Neurosci. 1998 Jul;1(3):183-4
references.pmid: 10195141
references.citation: Science. 2001 Sep 28;293(5539):2425-30
references.pmid: 11577229
references.citation: J Vis. 2008 Nov 17;8(15):8.1-10
references.pmid: 19146292
references.citation: Curr Biol. 2008 Feb 12;18(3):191-4
references.pmid: 18221876
references.citation: J Opt Soc Am A Opt Image Sci Vis. 2003 Jul;20(7):1434-48
references.pmid: 12868647
references.citation: J Neurosci. 2008 Oct 29;28(44):11315-27
references.pmid: 18971473
references.citation: J Neurosci. 2009 Feb 11;29(6):1688-98
references.pmid: 19211876
references.citation: Neuroimage. 2006 Mar;30(1):228-38
references.pmid: 16356738
references.citation: Vision Res. 2008 Sep;48(20):2143-53
references.pmid: 18619482
references.citation: J Cogn Neurosci. 2005 Apr;17(4):580-90
references.pmid: 15829079
references.citation: Neuroimage. 2003 Jun;19(2 Pt 1):261-70
references.pmid: 12814577
references.citation: Curr Biol. 2006 Jun 6;16(11):1096-102
references.pmid: 16753563
references.citation: Nat Neurosci. 2002 Jan;5(1):17-8
references.pmid: 11740503
references.citation: Cereb Cortex. 2003 Sep;13(9):911-20
references.pmid: 12902390
references.citation: Vision Res. 1998 Sep;38(18):2817-32
references.pmid: 9775328
references.citation: J Neurophysiol. 2001 Oct;86(4):2054-68
references.pmid: 11600661
references.citation: Nat Neurosci. 2005 May;8(5):679-85
references.pmid: 15852014
references.citation: J Neurophysiol. 2007 Dec;98(6):3436-49
references.pmid: 17898146
references.citation: Nat Rev Neurosci. 2006 Jul;7(7):523-34
references.pmid: 16791142
references.citation: J Vis. 2007;7(11):13.1-11
references.pmid: 18050885
references.citation: Curr Biol. 1997 Feb 1;7(2):144-7
references.pmid: 9016702
references.citation: Vision Res. 2006 Mar;46(6-7):1080-90
references.pmid: 16321419
references.citation: Nat Neurosci. 2002 Jun;5(6):589-97
references.pmid: 12021764
references.citation: Trends Cogn Sci. 2006 Sep;10(9):424-30
references.pmid: 16899397
references.citation: Perception. 2004;33(11):1279-90
references.pmid: 15693671
references.citation: Nat Neurosci. 2007 Jun;10(6):685-6
references.pmid: 17486103
references.citation: Neuroimage. 2004 Sep;23(1):156-66
references.pmid: 15325362
references.citation: Neuroimage. 2001 Nov;14(5):959-66
references.pmid: 11697928
references.citation: Nat Neurosci. 2005 Jun;8(6):820-7
references.pmid: 15864303
references.citation: Cereb Cortex. 2008 Oct;18(10):2416-38
references.pmid: 18281304
references.citation: J Neurosci. 2007 Nov 7;27(45):12321-30
references.pmid: 17989296
references.citation: Cognition. 2001 Aug;81(1):B1-9
references.pmid: 11525484