Sampling effects and measurement overlap can bias the inference of neuronal avalanches
Fig 5
Under coarse-sampling, apparent dynamics depend on the inter-electrode distance dE.
A: For small distances (dE = 100 μm), the avalanche-size distribution p(S) indicates (apparent) supercritical dynamics: p(S) ∼ S−α with a sharp peak near the electrode number NE = 64. For large distances (dE = 500 μm), p(S) indicates subcritical dynamics: p(S) ∼ S−α with a pronounced decay already for S < NE. There exists a sweet-spot value (dE = 250 μm) for which p(S) indicates critical dynamics: p(S) ∼ S−α until the the cut-off is reached at S = NE. The particular sweet-spot value of dE depends on time-bin size (here, Δt = 4 ms). As a guide to the eye, dashed lines indicate S−1.5. B: The inferred branching parameter is also biased by dE when estimated from neuronal avalanches. Apparent criticality (
, dotted line) is obtained with dE = 250 μm and Δt = 4 ms but also with dE = 400 μm and Δt = 8 ms. B, Inset: representation of the measurement overlap between neighboring electrodes; when electrodes are placed close to each other, spurious correlations are introduced.