TY - JOUR
T1 - Many neighbors are not silent. fMRI evidence for global lexical activity in visual word recognition
AU - Braun, Mario
AU - Jacobs, Arthur M.
AU - Richlan, Fabio
AU - Hawelka, Stefan
AU - Hutzler, Florian
AU - Kronbichler, Martin
PY - 2015/7/22
Y1 - 2015/7/22
N2 - Many neurocognitive studies investigated the neural correlates of visual word recognition, some of which manipulated the orthographic neighborhood density of words and nonwords believed to influence the activation of orthographically similar representations in a hypothetical mental lexicon. Previous neuroimaging research failed to find evidence for such global lexical activity associated with neighborhood density. Rather, effects were interpreted to reflect semantic or domain general processing. The present fMRI study revealed effects of lexicality, orthographic neighborhood density and a lexicality by orthographic neighborhood density interaction in a silent reading task. For the first time we found greater activity for words and nonwords with a high number of neighbors. We propose that this activity in the dorsomedial prefrontal cortex reflects activation of orthographically similar codes in verbal working memory thus providing evidence for global lexical activity as the basis of the neighborhood density effect. The interaction of lexicality by neighborhood density in the ventromedial prefrontal cortex showed lower activity in response to words with a high number compared to nonwords with a high number of neighbors. In the light of these results the facilitatory effect for words and inhibitory effect for nonwords with many neighbors observed in previous studies can be understood as being due to the operation of a fast-guess mechanism for words and a temporal deadline mechanism for nonwords as predicted by models of visual word recognition. Furthermore, we propose that the lexicality effect with higher activity for words compared to nonwords in inferior parietal and middle temporal cortex reflects the operation of an identification mechanism based on local lexico-semantic activity.
AB - Many neurocognitive studies investigated the neural correlates of visual word recognition, some of which manipulated the orthographic neighborhood density of words and nonwords believed to influence the activation of orthographically similar representations in a hypothetical mental lexicon. Previous neuroimaging research failed to find evidence for such global lexical activity associated with neighborhood density. Rather, effects were interpreted to reflect semantic or domain general processing. The present fMRI study revealed effects of lexicality, orthographic neighborhood density and a lexicality by orthographic neighborhood density interaction in a silent reading task. For the first time we found greater activity for words and nonwords with a high number of neighbors. We propose that this activity in the dorsomedial prefrontal cortex reflects activation of orthographically similar codes in verbal working memory thus providing evidence for global lexical activity as the basis of the neighborhood density effect. The interaction of lexicality by neighborhood density in the ventromedial prefrontal cortex showed lower activity in response to words with a high number compared to nonwords with a high number of neighbors. In the light of these results the facilitatory effect for words and inhibitory effect for nonwords with many neighbors observed in previous studies can be understood as being due to the operation of a fast-guess mechanism for words and a temporal deadline mechanism for nonwords as predicted by models of visual word recognition. Furthermore, we propose that the lexicality effect with higher activity for words compared to nonwords in inferior parietal and middle temporal cortex reflects the operation of an identification mechanism based on local lexico-semantic activity.
KW - Deadline mechanism
KW - Dorso- and ventromedial cortex
KW - Fast-guess mechanism
KW - Identification mechanism
KW - Mental lexicon
KW - Neighborhood density effect
KW - Orthographic similarity
KW - Visual word recognition
UR - https://pubmed.ncbi.nlm.nih.gov/26257634/
UR - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510423/
UR - http://www.scopus.com/inward/record.url?scp=84937845923&partnerID=8YFLogxK
UR - https://resolver.obvsg.at/urn:nbn:at:at-ubs:3-7800
UR - https://www.mendeley.com/catalogue/3bd8748e-5dbc-3244-a2f5-572237bd313e/
U2 - 10.3389/fnhum.2015.00423
DO - 10.3389/fnhum.2015.00423
M3 - Article
C2 - 26257634
SN - 1662-5161
VL - 9
JO - Frontiers in Human Neuroscience
JF - Frontiers in Human Neuroscience
M1 - 423
ER -