TY  - JOUR
AU  - Heim, S.
AU  - Eickhoff, S. B.
AU  - Ischebeck, A. K.
AU  - Friederici, A.
AU  - Stephan, K. E.
AU  - Amunts, K.
TI  - Effective Connectivity of the Left BA44, BA45, and Inferior Temporal Gyrus during Lexical and Phonological Decisions Identified with DCM
JO  - Human brain mapping
VL  - 30
SN  - 1065-9471
CY  - New York, NY
PB  - Wiley-Liss
M1  - PreJuSER-3457
SP  - 392 - 402
PY  - 2009
N1  - Record converted from VDB: 12.11.2012
AB  - Distinct regions in the left inferior frontal gyrus (IFG) preferentially support the processing of different word-types (e.g., real words, pseudowords) and tasks (e.g., lexical decisions, phonological decisions) in visual word recognition. However, the functional connectivity underlying the task-related specialisation of regions in the left IFG is not yet well understood. In this study we investigated the neural mechanisms driving the interaction of WORD-TYPE (real word vs. pseudoword) and TASK (lexical vs. phonological decision) in Brodmann's area (BA) 45 in the left IFG using dynamic causal modelling (DCM). Four different models were compared, all of which included left BA44, left BA45, and left inferior temporal gyrus (ITG). In each model, the visual presentation of words and pseudowords is assumed to directly evoke activity in the ITG and is then thought to be subsequently propagated to BA45 and to BA44 via direct intrinsic connections. The models differed with regard to which connections were modulated by the different tasks. Both tasks were assumed to either modulate the ITG_BA45 connection (Model #1), or the BA44_BA45 connection (Model #2), or both connections in parallel (Model #3). In Model #4 lexical decisions modulated the ITG_BA45 connection, whereas phonological decisions modulated the BA44_BA45 connection. Bayesian model selection revealed a superiority of Model #1. In this model, the strength of the ITG_BA45 connection was enhanced during lexical decisions. This model is in line with the hypothesis that left BA 45 supports explicit lexical decisions during visual word recognition based on lexical access in the ITG.
KW  - Adult
KW  - Bayes Theorem
KW  - Decision Making: physiology
KW  - Dominance, Cerebral: physiology
KW  - Efferent Pathways: anatomy & histology
KW  - Efferent Pathways: physiology
KW  - Female
KW  - Frontal Lobe: anatomy & histology
KW  - Frontal Lobe: physiology
KW  - Humans
KW  - Language
KW  - Language Tests
KW  - Magnetic Resonance Imaging
KW  - Male
KW  - Pattern Recognition, Visual: physiology
KW  - Phonetics
KW  - Photic Stimulation
KW  - Reading
KW  - Symbolism
KW  - Temporal Lobe: physiology
KW  - Verbal Behavior: physiology
KW  - Young Adult
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:18095285
UR  - <Go to ISI:>//WOS:000263232800005
DO  - DOI:10.1002/hbm.20512
UR  - https://juser.fz-juelich.de/record/3457
ER  -