Intersubject consistency of cortical MEG signals during movie viewing

Neuroimage. 2014 May 15;92:217-24. doi: 10.1016/j.neuroimage.2014.02.004. Epub 2014 Feb 12.

Abstract

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 10 Hz; the maximum correlation was 0.28 ± 0.075 in the ≤1 Hz 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.

Keywords: Magnetoencephalography (MEG); Minimum norm estimate (MNE); Movie; Multi-set canonical correlation analysis (M-CCA); Spatial filtering.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain Mapping / methods*
  • Cerebral Cortex / physiology*
  • Evoked Potentials, Visual / physiology*
  • Feasibility Studies
  • Female
  • Humans
  • Magnetoencephalography / methods*
  • Male
  • Middle Aged
  • Motion Pictures*
  • Nerve Net / physiology*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Visual Perception / physiology*