Journal Article

PreJuSER-5705

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Different roles of cytoarchitectonic BA44 and BA45 in phonological and semantic verbal fluency as revealed by dynamic causal modelling

Heim, S.FZJ* ; Eickhoff, S. B.FZJ* ; Amunts, K.FZJ*

2009
Academic Press Orlando, Fla.

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Please use a persistent id in citations: doi:10.1016/j.neuroimage.2009.06.044

Abstract: The interactions of left cytoarchitectonic BA 44 and BA 45 during semantic and phonological verbal fluency tasks were investigated using dynamic causal modelling (DCM). Three different models were tested, all of which featured BA 44 and BA 45 as top-down driven interconnected nodes projecting to the motor cortex as the final output region. Model #1 represents the hypothesis that BA 45 is involved in lexical retrieval including both semantic and phonological processes, while BA 44 supports other phonological processes. Model #2 reflects the notion of a clear-cut segregation of computational processes sustained by BA 44 (phonological processing) and BA 45 (semantic processing). Model #3 was based on the hypothesis that both BA 44 and BA 45 support semantic and phonological processing. When these models were compared against each other by Bayesian model selection, evidence emerged in favour of the first model, implying that BA 45 supports word retrieval processes whereas BA 44 is involved in processing phonological information during word generation. In a subsequent analysis of the derived model parameters for model #1, all connection strengths were significantly positive except for the inhibitory coupling between BA 44 and BA 45. This inhibition may reflect how the phonological analysis in BA 44 during word generation constrains lexical word retrieval in BA 45. To conclude, DCM provided additional insights into the roles of BA 44 and BA 45 during verbal fluency revealing the involvement of BA 45 in lexical retrieval and the relevance of BA 44 for phonological processing during word generation.

Keyword(s): Adult (MeSH) ; Bayes Theorem (MeSH) ; Computer Simulation (MeSH) ; Female (MeSH) ; Frontal Lobe: physiology (MeSH) ; Humans (MeSH) ; Language (MeSH) ; Language Tests (MeSH) ; Linear Models (MeSH) ; Linguistics (MeSH) ; Magnetic Resonance Imaging (MeSH) ; Male (MeSH) ; Mental Processes: physiology (MeSH) ; Models, Neurological (MeSH) ; Motor Cortex: physiology (MeSH) ; Neural Inhibition (MeSH) ; Neural Pathways: physiology (MeSH) ; Phonetics (MeSH) ; Psychomotor Performance: physiology (MeSH) ; Speech: physiology (MeSH) ; J

Note: This Human Brain Project/Neuroinformatics research is funded by the National Institute of Biomedical Imaging and Bioengineering, the National Institute of Neurological Disorders and Stroke, and the National Institute of Mental Health (KA). Further support by the Brain Imaging Center West (BMBF 01GO0204) is gratefully acknowledged. We thank N. Jon Shah for the support of the NMR group at the INB-3 during fMRI data acquisition, in particular Barbara Elghahwagi for her assistance with fMRI data recording. Moreover, we appreciate the support by the Cognitive Neurology group at the INB-3, in particular by Ralph Weidner, Shahram Mirzazade, and Marcus Wilms, with respect to the peripheral stimulation devices.

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Contributing Institute(s):

1. Molekulare Organisation des Gehirns (INM-2)
2. Strukturelle und funktionelle Organisation des Gehirns (INM-1)
3. Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA-BRAIN)

Research Program(s):

1. Funktion und Dysfunktion des Nervensystems (P33)

Appears in the scientific report 2009

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