Group imaging of task-related changes in cortical synchronisation using nonparametric permutation testing

Krish D Singh, Gareth R Barnes, Arjan Hillebrand

Research output: Contribution to journalArticleAcademicpeer-review

208 Citations (Scopus)


Synthetic aperture magnetometry (SAM) is a nonlinear beamformer technique for producing 3D images of cortical activity from magnetoencephalography data. We have previously shown how SAM images can be spatially normalised and averaged to form a group image. In this paper we show how nonparametric permutation methods can be used to make robust statistical inference about group SAM data. Data from a biological motion direction discrimination experiment were analysed using both a nonparametric analysis toolbox (SnPM) and a conventional parametric approach utilising Gaussian field theory. In data from a group of six subjects, we were able to show robust group activation at the P < 0.05 (corrected) level using the nonparametric methods, while no significant clusters were found using the conventional parametric approach. Activation was found using SnPM in several regions of right occipital-temporal cortex, including the superior temporal sulcus, V5/MT, the fusiform gyrus, and the lateral occipital complex.

Original languageEnglish
Pages (from-to)1589-601
Number of pages13
Issue number4
Publication statusPublished - Aug 2003
Externally publishedYes


  • Adult
  • Cerebral Cortex/physiology
  • Cortical Synchronization
  • Female
  • Fourier Analysis
  • Humans
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional
  • Magnetics
  • Magnetoencephalography
  • Male
  • Mathematical Computing
  • Motion Perception/physiology
  • Nerve Net/physiology
  • Normal Distribution
  • Occipital Lobe/physiology
  • Orientation/physiology
  • Pattern Recognition, Visual/physiology
  • Psychomotor Performance/physiology
  • Software
  • Statistics, Nonparametric
  • Temporal Lobe/physiology

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