Figure 1. | What the success of brain imaging implies about the neural code

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What the success of brain imaging implies about the neural code

Figure 1.

Affiliation details

University College London, United Kingdom; The Alan Turing Institute, United Kingdom
Figure 1.
Download figureOpen in new tabFigure 1. The activity of neurons in the top-left panel gradually changes from left to right, whereas changes are more abrupt in the top-middle and top-right panels.

Each square in the grid represents a voxel which summates activity within its frame as shown in the bottom panels. For the smoother pattern of neural activity, the summation of each voxel (bottom left) captures the changing gradient from left to right depicted in the top-left, whereas for the less smooth representation in the middle panel all voxels sum to the same orange value (bottom middle). Thus, differences in activation of yellow vs. red neurons are detectable using fMRI for the smooth case, but not for the less smooth case because voxel response is homogenous. Improving spatial resolution (right panels) by reducing voxel size overcomes these sampling limits, resulting in voxel inhomogeneity (bottom-right panel).

DOI: http://dx.doi.org/10.7554/eLife.21397.003