Understanding multivariate brain activity: Evaluating the effect of voxelwise noise correlations on population codes in functional magnetic resonance imaging
Fig 1
The pool consists of two responsive voxels and the two color disks represent the trial-by-trial response distributions evoked by two different stimuli. Panel A illustrates the original state of the population responses. Decoding performance can be improved via either a bigger separation of the mean population response (panel B) or changes in the covariance structure (panel C). Representational structures in panels B and C indicate improved population codes but have distinct underlying mechanisms. Panel D illustrates that certain covariance changes can worsen decoding.