PMID- 21160549
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20110714
LR  - 20211020
IS  - 1662-5137 (Electronic)
IS  - 1662-5137 (Linking)
VI  - 4
DP  - 2010
TI  - Greater Pre-Stimulus Effective Connectivity from the Left Inferior Frontal Area 
      to other Areas is Associated with Better Phonological Decoding in Dyslexic 
      Readers.
PG  - 156
LID - 10.3389/fnsys.2010.00156 [doi]
LID - 156
AB  - Functional neuroimaging studies suggest that neural networks that subserve 
      reading are organized differently in dyslexic readers (DRs) and typical readers 
      (TRs), yet the hierarchical structure of these networks has not been well 
      studied. We used Granger causality to examine the effective connectivity of the 
      preparatory network that occurs prior to viewing a non-word stimulus that 
      requires phonological decoding in 7 DRs and 10 TRs who were young adults. The 
      neuromagnetic activity that occurred 500 ms prior to each rhyme trial was 
      analyzed from sensors overlying the left and right inferior frontal areas (IFA), 
      temporoparietal areas, and ventral occipital-temporal areas within the low, 
      medium, and high beta and gamma sub-bands. A mixed-model analysis determined 
      whether connectivity to or from the left and right IFAs differed across 
      connectivity direction (into vs. out of the IFAs), brain areas, reading group, 
      and/or performance. Results indicated that greater connectivity in the low beta 
      sub-band from the left IFA to other cortical areas was significantly related to 
      better non-word rhyme discrimination in DRs but not TRs. This suggests that the 
      left IFA is an important cortical area involved in compensating for poor 
      phonological function in DRs. We suggest that the left IFA activates a wider-than 
      usual network prior to each trial in the service of supporting otherwise 
      effortful phonological decoding in DRs. The fact that the left IFA provides 
      top-down activation to both posterior left hemispheres areas used by TRs for 
      phonological decoding and homologous right hemisphere areas is discussed. In 
      contrast, within the high gamma sub-band, better performance was associated with 
      decreased connectivity between the left IFA and other brain areas, in both 
      reading groups. Overly strong gamma connectivity during the pre-stimulus period 
      may interfere with subsequent transient activation and deactivation of 
      sub-networks once the non-word appears.
FAU - Frye, Richard E
AU  - Frye RE
AD  - Department of Pediatrics, Division of Child and Adolescent Neurology and the 
      Children's Learning Institute, University of Texas Health Science Center Houston, 
      TX, USA.
FAU - Wu, Meng-Hung
AU  - Wu MH
FAU - Liederman, Jacqueline
AU  - Liederman J
FAU - Fisher, Janet McGraw
AU  - Fisher JM
LA  - eng
GR  - K23 NS046565/NS/NINDS NIH HHS/United States
PT  - Journal Article
DEP - 20101202
PL  - Switzerland
TA  - Front Syst Neurosci
JT  - Frontiers in systems neuroscience
JID - 101477946
PMC - PMC3001755
OTO - NOTNLM
OT  - Granger causality
OT  - compensatory mechanisms
OT  - dyslexia
OT  - effective connectivity
OT  - magnetoencephalography
OT  - reading
OT  - top-down
EDAT- 2010/12/17 06:00
MHDA- 2010/12/17 06:01
PMCR- 2010/01/01
CRDT- 2010/12/17 06:00
PHST- 2010/06/15 00:00 [received]
PHST- 2010/11/08 00:00 [accepted]
PHST- 2010/12/17 06:00 [entrez]
PHST- 2010/12/17 06:00 [pubmed]
PHST- 2010/12/17 06:01 [medline]
PHST- 2010/01/01 00:00 [pmc-release]
AID - 10.3389/fnsys.2010.00156 [doi]
PST - epublish
SO  - Front Syst Neurosci. 2010 Dec 2;4:156. doi: 10.3389/fnsys.2010.00156. eCollection 
      2010.