RESEARCH ARTICLE
Inter-Subject Synchronization of Prefrontal Cortex Hemodynamic Activity During Natural Viewing
Iiro P Jääskeläinen*, 1, 2, Katri Koskentalo1, 2, Marja H Balk1, 2, 3, Taina Autti3, Jaakko Kauramäki1, 2, Cajus Pomren1, 2, Mikko Sams1, 2
Article Information
Identifiers and Pagination:
Year: 2008Volume: 2
First Page: 14
Last Page: 19
Publisher ID: TONIJ-2-14
DOI: 10.2174/1874440000802010014
PMID: 19018313
PMCID: PMC2577941
Article History:
Received Date: 25/2/2008Revision Received Date: 8/3/2008
Acceptance Date: 12/3/2008
Electronic publication date: 1/4/2008
Collection year: 2008

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.5/), which permits unrestrictive use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Hemodynamic activity in occipital, temporal, and parietal cortical areas were recently shown to correlate across subjects during viewing of a 30-minute movie clip. However, most of the frontal cortex lacked between-subject correlations. Here we presented 12 healthy naïve volunteers with the first 72 minutes of a movie (“Crash”, 2005, Lions Gate Films) outside of the fMRI scanner to involve the subjects in the plot of the movie, followed by presentation of the last 36 minutes during fMRI scanning. We observed significant between-subjects correlation of fMRI activity in especially right hemisphere frontal cortical areas, in addition to the correlation of activity in temporal, occipital, and parietal areas. It is possible that this resulted from the subjects following the plot of the movie and being emotionally engaged in the movie during fMRI scanning. We further show that probabilistic independent component analysis (ICA) reveals meaningful activations in individual subjects during natural viewing.