Intersubject consistency of cortical MEG signals during movie viewing

• Published in: NeuroImage (Orlando, Fla.) Vol. 92; pp. 217 - 224
• Main Authors: Lankinen, K., Saari, J., Hari, R., Koskinen, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 15.05.2014; Elsevier; Elsevier Limited
• Subjects: Adult; Biological and medical sciences; Brain; Brain Mapping - methods; Brain research; Cerebral Cortex - physiology; Evoked Potentials, Visual - physiology; Feasibility Studies; Female; Fundamental and applied biological sciences. Psychology; Humans; Magnetoencephalography (MEG); Magnetoencephalography - methods; Male; Middle Aged; Minimum norm estimate (MNE); Motion Pictures; Movie; Multi-set canonical correlation analysis (M-CCA); Multinational corporations; Nerve Net - physiology; Reproducibility of Results; Sensitivity and Specificity; Spatial filtering; Studies; Vertebrates: nervous system and sense organs; Visual Perception - physiology; Movie; Magnetoencephalography (MEG); Multi-set canonical correlation analysis (M-CCA); Spatial filtering; Minimum norm estimate (MNE); Magnetoencephalography
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2014.02.004

According to recent functional magnetic resonance imaging (fMRI) studies, spectators of a movie may share similar spatiotemporal patterns of brain activity. We aimed to extend these findings of intersubject correlation to temporally accurate single-trial magnetoencephalography (MEG). A silent 15-min black-and-white movie was shown to eight subjects twice. We adopted a spatial filtering model and estimated its parameter values by using multi-set canonical correlation analysis (M-CCA) so that the intersubject correlation was maximized. The procedure resulted in multiple (mutually uncorrelated) time-courses with statistically significant intersubject correlations at frequencies below 10Hz; the maximum correlation was 0.28±0.075 in the ≤1Hz band. Moreover, the 24-Hz frame rate elicited steady-state responses with statistically significant intersubject correlations up to 0.29±0.12. To assess the brain origin of the across-subjects correlated signals, the time-courses were correlated with minimum-norm source current estimates (MNEs) projected to the cortex. The time series implied across-subjects synchronous activity in the early visual, posterior and inferior parietal, lateral temporo-occipital, and motor cortices, and in the superior temporal sulcus (STS) bilaterally. These findings demonstrate the capability of the proposed methodology to uncover cortical MEG signatures from single-trial signals that are consistent across spectators of a movie. •Intersubject synchronization during movie viewing was studied with MEG.•Correlations were computed by multi-set canonical correlation analysis (M-CCA).•Time courses correlated between subjects at <10Hz and at the frame rate.