title: Dynamic discrimination analysis: a spatial-temporal SVM.
abstract: Recently, pattern recognition methods (e.g., support vector machines (SVM)) have been used to analyze fMRI data. In these applications the fMRI scans are treated as spatial patterns and statistical learning methods are used to identify statistical properties of the data that discriminate between brain states (e.g., task 1 vs. task 2) or group of subjects (e.g., patients and controls). We propose an extension of these approaches using temporal embedding. This makes the dynamic aspect of fMRI time series an explicit part of the classification. The proposed pattern recognition approach uses both spatial and temporal information. Temporal embedding was implemented by defining spatiotemporal fMRI observations and applying a support vector machine to these temporally extended observations. This produces a discriminating weight vector encompassing both voxels and time. The resulting vector furnishes discriminating responses, at each voxel without imposing any constraints on their temporal form.
authors.affiliation: Brain Image Analysis Unit, Biostatics Department, Centre for Neuroimaging Sciences (PO 89), Institute of Psychiatry, KCL, De Crespigny Park, London SE5 8AF, UK. Janaina.Mourao-Miranda@iop.kcl.ac.uk
authors.forename: Janaina
authors.initials: J
authors.lastname: Mourão-Miranda
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Friston
authors.forename: Michael
authors.initials: M
authors.lastname: Brammer
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology; D001143:Arousal / Q000502:physiology; D001185:Artificial Intelligence; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008432:Mathematical Computing; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted
chemical_list: D010100:Oxygen