title: Two sides of meaning: the scalp-recorded n400 reflects distinct contributions from the cerebral hemispheres.
abstract: The N400, a component of the event-related potential (ERP) associated with the processing of meaning, is sensitive to a wide array of lexico-semantic, sentence-level, and discourse-level manipulations across modalities. In sentence contexts, N400 amplitude varies inversely and nearly linearly with the predictability of a word in its context. However, recent theories and empirical evidence from studies employing the visual half-field technique (to selectively bias processing to one cerebral hemisphere) suggest that the two hemispheres use sentence context information in different ways. Thus, each hemisphere may not respond to manipulations of contextual predictability in an equivalent manner. This possibility was investigated by recording ERPs while presenting [in the left and right visual fields (VFs)] sentence-final words that varied over the full range of sentence-level predictability. RVF/left hemisphere items were facilitated (as evidenced by reduced N400 amplitudes) over a broader range of predictability compared with LVF/right hemisphere items, although both strongly predictable and completely unexpected items evoked similar responses in each VF/hemisphere. Further, the pattern of N400 amplitudes over the full range of predictability significantly differed from a linear response function for both VFs/hemispheres. This suggests that the N400 response recorded with standard central field presentation comprises different contributions from both cerebral hemispheres, neither of which on its own is sensitive to contextual predictability in an evenly graded manner. These data challenge the notion of a singular or unitary mode of comprehension and instead support the view that the left and right hemispheres instantiate unique, complementary language comprehension architectures in parallel.
authors: Beckman Institute, University of Illinois Urbana, IL, USA.
authors: Edward W
authors: EW
authors: Wlotko
authors: Kara D
authors: KD
authors: Federmeier
keywords: N400; event-related potentials; hemispheric asymmetry; hemispheric cooperation; hierarchical linear modeling; language; predictability; sentential constraint
references: J Neurosci. 1991 Aug;11(8):2281-7
references: 1869914
references: Psychon Bull Rev. 1995 Mar;2(1):20-54
references: 24203589
references: Brain Lang. 1983 Jan;18(1):20-7
references: 6839130
references: Brain Lang. 2005 Dec;95(3):383-94
references: 16298668
references: Lang Linguist Compass. 2008 Jan 1;2(1):1-17
references: 19777128
references: Int J Psychophysiol. 2012 Feb;83(2):176-90
references: 22019481
references: Behav Brain Sci. 2003 Dec;26(6):651-65; discussion 666-707
references: 15377127
references: Nat Neurosci. 2005 Mar;8(3):389-95
references: 15723061
references: Science. 1970 Nov 27;170(3961):940-4
references: 5475022
references: Neuropsychologia. 2010 Nov;48(13):3772-81
references: 20638397
references: Neuropsychologia. 1971 Mar;9(1):97-113
references: 5146491
references: Neuropsychologia. 2007 Oct 1;45(13):3001-14
references: 17659309
references: Psychophysiology. 2007 Jul;44(4):491-505
references: 17521377
references: J Mem Lang. 2009 Oct 1;61(3):326-338
references: 20161064
references: Neuroimage. 2005 Apr 15;25(3):1002-15
references: 15809000
references: Brain Lang. 2006 Jun;97(3):279-93
references: 16343606
references: Psychol Aging. 2012 Dec;27(4):975-88
references: 22775363
references: Trends Cogn Sci. 2005 Nov;9(11):512-8
references: 16214387
references: Brain Res Cogn Brain Res. 1999 Oct 25;8(3):373-92
references: 10556614
references: Brain Lang. 1991 Jan;40(1):89-105
references: 2009449
references: Psychophysiology. 2012 Jun;49(6):770-85
references: 22469362
references: Psychophysiology. 1995 Nov;32(6):511-25
references: 8524986
references: Psychol Rev. 2001 Jan;108(1):204-56
references: 11212628
references: Brain Lang. 1999 Jun 1-15;68(1-2):5-15
references: 10433733
references: Cognition. 2004 May-Jun;92(1-2):1-12
references: 15037124
references: Cognition. 2004 May-Jun;92(1-2):13-45
references: 15037125
references: J Cogn Neurosci. 2004 Sep;16(7):1272-88
references: 15453979
references: Neuropsychologia. 1997 Apr;35(4):497-504
references: 9106278
references: Neuropsychologia. 2007 Apr 9;45(8):1777-90
references: 17291547
references: Neuropsychologia. 2001;39(13):1451-63
references: 11585613
references: J Exp Psychol Learn Mem Cogn. 2005 Jan;31(1):129-47
references: 15641911
references: J Exp Psychol Learn Mem Cogn. 2005 May;31(3):443-67
references: 15910130
references: Brain Res. 2007 May 18;1146:75-84
references: 16901469
references: Neuroimage. 2012 Aug 1;62(1):356-66
references: 22565202
references: Annu Rev Psychol. 2011;62:621-47
references: 20809790
references: Nat Neurosci. 2005 Aug;8(8):1117-21
references: 16007080
references: Annu Rev Neurosci. 2002;25:151-88
references: 12052907
references: Brain Cogn. 1998 Mar;36(2):128-57
references: 9520311
references: Nature. 1984 Jan 12-18;307(5947):161-3
references: 6690995
references: Brain Lang. 2003 Jun;85(3):503-23
references: 12744960
references: Neuropsychologia. 2006;44(12):2348-59
references: 16806316
references: Brain Cogn. 1998 Mar;36(2):193-208
references: 9520313
references: Int J Psychophysiol. 2012 Mar;83(3):382-92
references: 22226800
references: J Exp Psychol Hum Percept Perform. 1989 Nov;15(4):711-22
references: 2531206
references: Mem Cognit. 2005 Jul;33(5):871-86
references: 16383175
references: Neuropsychologia. 2005;43(1):128-41
references: 15488912
references: Trends Cogn Sci. 2000 Dec 1;4(12):463-470
references: 11115760
references: Brain. 2000 Feb;123 ( Pt 2):291-307
references: 10648437
references: Neuropsychologia. 2009 Jan;47(2):473-80
references: 18952115
references: Psychon Bull Rev. 2005 Dec;12(6):993-8
references: 16615318
references: Neuropsychologia. 2003;41(4):480-92
references: 12559164