Comment on "Criticality Between Cortical States"

and collaborators reported extensive analyses of power-law scalings of neuronal avalanches in experimental recordings and in a critical theoretical model. One of their main conclusions is that the brain operates at criticality in specific regimes. To prove this point, they developed a test (hereafter, Fontenele test) for criticality, which they indicate to rely on our own theoretical result. However, the results we established do not provide necessary and sufficient conditions for criticality, and cannot be extrapolated to derive a test for criticality. Moreover, the authors did not include any control applying the test to non-critical systems, to assess possible differences with the experimental data. We propose here two such controls, and show that the test can misclassify as critical these non-critical systems. This implies that the analyses of et al. do not support their conclusions, and the question of whether the brain operates at criticality remains open.