Phonological decisions require both the left and right supramarginal gyri.
Recent functional imaging studies demonstrated that both the left and right supramarginal gyri (SMG) are activated when healthy right-handed subjects make phonological word decisions. However, lesion studies typically report difficulties with phonological processing after left rather than right hemisphere damage. Here, we used a unique dual-site transcranial magnetic stimulation (TMS) approach to test whether the SMG in the right hemisphere contributes to modality-independent (i.e., auditory and visual) phonological decisions. To test task-specificity, we compared the effect of real or sham TMS during phonological, semantic, and perceptual decisions. To test laterality and anatomical specificity, we compared the effect of TMS over the left, right, or bilateral SMG and angular gyri. The accuracy and reaction times of phonological decisions were selectively disrupted relative to semantic and perceptual decisions when real TMS was applied over the left, right, or bilateral SMG. These effects were not observed for TMS over the angular gyri. A follow-up experiment indicated that the threshold-intensity for inducing a disruptive effect on phonological decisions was identical for unilateral TMS over the right or left SMG. Taken together, these findings provide converging evidence that the right SMG contributes to accurate and efficient phonological decisions in the healthy brain, with no evidence that the left and right SMG can compensate for one another during TMS. Our findings motivate detailed studies of phonological processing in patients with acute or long-term damage of the right SMG.
Hartwigsen
Gesa
G
Department of Neurology, Christian-Albrechts-University Kiel, 24105 Kiel, Germany. Gesa.Hartwigsen@gmx.de
Baumgaertner
Annette
A
Price
Cathy J
CJ
Koehnke
Maria
M
Ulmer
Stephan
S
Siebner
Hartwig R
HR
D000328:Adult; D001307:Auditory Perception; D001931:Brain Mapping; D003657:Decision Making; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D010296:Parietal Lobe / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012660:Semantics; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
Clin Neuropsychol. 2010 Jan;24(1):57-69
19557656
J Physiol. 1992;453:525-46
1464843
Cortex. 2009 Oct;45(9):1091-6
19232583
Trends Cogn Sci. 2006 Nov;10(11):480-6
16997610
Acta Neurol Belg. 2008 Dec;108(4):161-6
19239047
J Cereb Blood Flow Metab. 2006 Sep;26(9):1122-7
16757978
J Neurophysiol. 2005 Dec;94(6):4520-7
16135552
Electroencephalogr Clin Neurophysiol. 1998 Jan;108(1):1-16
9474057
J Neurol. 2009 Sep;256(9):1461-7
19363625
Cortex. 2006 Jul;42(5):774-81
16909638
Brain. 2006 Jun;129(Pt 6):1371-84
16638796
Neuropsychologia. 1999 Feb;37(2):125-35
10080370
J Physiol. 2006 Aug 1;574(Pt 3):917-28
16581858
Neuroimage. 2006 Jul 15;31(4):1453-74
16571375
J Cogn Neurosci. 2006 Jul;18(7):1147-55
16839288
Cortex. 2009 Oct;45(9):1035-42
19371866
Lancet Neurol. 2003 Mar;2(3):145-56
12849236
Neuroreport. 2001 Sep 17;12(13):2785-90
11588577
J Neurophysiol. 1998 Feb;79(2):1102-7
9463466
Hum Brain Mapp. 2010 Mar;31(3):365-77
19777554
J Cogn Neurosci. 1997 Nov;9(6):727-33
23964595
J Cogn Neurosci. 2003 Jan 1;15(1):71-84
12590844
Neurosci Lett. 1994 Nov 21;182(1):25-8
7891880
J Neurosci. 2005 Aug 31;25(35):8010-6
16135758
J Cogn Neurosci. 2004 Mar;16(2):289-300
15068598
Neuroimage. 2009 Jan 15;44(2):563-8
18848630
Trends Cogn Sci. 2002 Oct 1;6(10):416-421
12413574
Cereb Cortex. 2009 Jun;19(6):1474-85
18987393
Cognition. 2004 May-Jun;92(1-2):67-99
15037127
Neuroscientist. 2008 Feb;14(1):119-27
17911215
Neuropsychologia. 1971 Mar;9(1):97-113
5146491
J Physiol. 1993 Nov;471:501-19
8120818
Stroke. 2007 Apr;38(4):1286-92
17322084
Neuropsychologia. 2003;41(3):293-303
12457755
J Neurol Sci. 1998 Feb 5;154(2):182-93
9562309
Ann N Y Acad Sci. 2010 Mar;1191:62-88
20392276
Cereb Cortex. 2007 Dec;17(12):2841-52
17337745
J Cogn Neurosci. 2004 Mar;16(2):178-88
15068590