PMID- 24999323
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20140707
LR  - 20240321
IS  - 1662-5161 (Print)
IS  - 1662-5161 (Electronic)
IS  - 1662-5161 (Linking)
VI  - 8
DP  - 2014
TI  - Assessing direct paths of intracortical causal information flow of oscillatory 
      activity with the isolated effective coherence (iCoh).
PG  - 448
LID - 10.3389/fnhum.2014.00448 [doi]
LID - 448
AB  - Functional connectivity is of central importance in understanding brain function. 
      For this purpose, multiple time series of electric cortical activity can be used 
      for assessing the properties of a network: the strength, directionality, and 
      spectral characteristics (i.e., which oscillations are preferentially 
      transmitted) of the connections. The partial directed coherence (PDC) of Baccala 
      and Sameshima (2001) is a widely used method for this problem. The three aims of 
      this study are: (1) To show that the PDC can misrepresent the frequency response 
      under plausible realistic conditions, thus defeating the main purpose for which 
      the measure was developed; (2) To provide a solution to this problem, namely the 
      "isolated effective coherence" (iCoh), which consists of estimating the partial 
      coherence under a multivariate autoregressive model, followed by setting all 
      irrelevant associations to zero, other than the particular directional 
      association of interest; and (3) To show that adequate iCoh estimators can be 
      obtained from non-invasively computed cortical signals based on exact low 
      resolution electromagnetic tomography (eLORETA) applied to scalp EEG recordings. 
      To illustrate the severity of the problem with the PDC, and the solution achieved 
      by the iCoh, three examples are given, based on: (1) Simulated time series with 
      known dynamics; (2) Simulated cortical sources with known dynamics, used for 
      generating EEG recordings, which are then used for estimating (with eLORETA) the 
      source signals for the final connectivity assessment; and (3) EEG recordings in 
      rats. Lastly, real human recordings are analyzed, where the iCoh between six 
      cortical regions of interest are calculated and compared under eyes open and 
      closed conditions, using 61-channel EEG recordings from 109 subjects. During eyes 
      closed, the posterior cingulate sends alpha activity to all other regions. During 
      eyes open, the anterior cingulate sends theta-alpha activity to other frontal 
      regions.
FAU - Pascual-Marqui, Roberto D
AU  - Pascual-Marqui RD
AD  - The KEY Institute for Brain-Mind Research, University of Zurich Zurich, 
      Switzerland ; Department of Neuropsychiatry, Kansai Medical University Osaka, 
      Japan.
FAU - Biscay, Rolando J
AU  - Biscay RJ
AD  - CIMFAV, Universidad de Valparaiso Valparaiso, Chile.
FAU - Bosch-Bayard, Jorge
AU  - Bosch-Bayard J
AD  - Neuroinformatic Department, Cuban Neuroscience Center Havana, Cuba.
FAU - Lehmann, Dietrich
AU  - Lehmann D
AD  - The KEY Institute for Brain-Mind Research, University of Zurich Zurich, 
      Switzerland.
FAU - Kochi, Kieko
AU  - Kochi K
AD  - The KEY Institute for Brain-Mind Research, University of Zurich Zurich, 
      Switzerland.
FAU - Kinoshita, Toshihiko
AU  - Kinoshita T
AD  - Department of Neuropsychiatry, Kansai Medical University Osaka, Japan.
FAU - Yamada, Naoto
AU  - Yamada N
AD  - Department of Psychiatry, Shiga University of Medical Science Shiga, Japan.
FAU - Sadato, Norihiro
AU  - Sadato N
AD  - Division of Cerebral Integration, National Institute for Physiological Sciences 
      Okazaki, Japan.
LA  - eng
PT  - Journal Article
DEP - 20140620
PL  - Switzerland
TA  - Front Hum Neurosci
JT  - Frontiers in human neuroscience
JID - 101477954
PMC - PMC4064566
OTO - NOTNLM
OT  - LORETA
OT  - alpha oscillation connectivity
OT  - causal intracortical connectivity
OT  - isolated effective coherence
OT  - resting state electriphysiological connectivity
EDAT- 2014/07/08 06:00
MHDA- 2014/07/08 06:01
PMCR- 2014/01/01
CRDT- 2014/07/08 06:00
PHST- 2014/05/08 00:00 [received]
PHST- 2014/06/03 00:00 [accepted]
PHST- 2014/07/08 06:00 [entrez]
PHST- 2014/07/08 06:00 [pubmed]
PHST- 2014/07/08 06:01 [medline]
PHST- 2014/01/01 00:00 [pmc-release]
AID - 10.3389/fnhum.2014.00448 [doi]
PST - epublish
SO  - Front Hum Neurosci. 2014 Jun 20;8:448. doi: 10.3389/fnhum.2014.00448. eCollection 
      2014.