fMRI: Can MVPA Really Help Crack The Neural Code?

Multivoxel Pattern Analysis (MVPA) is the latest big thing in the neuroimaging world. MVPA is a multivariate statistical technique that can be applied to fMRI brain scan results as an alternative to conventional univariate methods of finding brain activation. Neuroscientists love MVPA for two reasons: first, it offers more 'blobs for your buck' - it often detects neural signals that don't show up on conventional scans. Secondly, it seems to offer a way to go beyond merely detecting and localizing activity and actually provide insights into how information is represented in the brain. MVPA promises to not just locate but also 'decode' the brain's activity, one of the Holy Grails of modern neuroscience. But Texas-based neuroscientists Tyler Davis and colleagues offer an important note of caution in a new NeuroImage paper: What do differences between multi-voxel and univariate analysis mean? They show convincingly that we can't assume that MVPA tells us anything special about the neural code.