Fig. 3.
The avalanche organization is scale-invariant to nLFP amplitude threshold. (A) Decay in total number of nLFPs with increase in threshold z. (B) Power law distributions in sizes are scale-invariant with respect to nLFP amplitude. Size distributions P(s) plotted for different z and two arrays (Δt = 4 ms). (C) The slope α does not depend on z (five arrays; color code in A). (D) Random removal of nLFPs differs from threshold-dependent nLFP removal and does not maintain scale- invariance. Filled circles: cluster size distribution at z = −1.5SD (original data, monkey A). Open circles: nLFPs are randomly removed from the original −1.5SD raster to arrive at rasters with equivalent number of nLFPs as found for z = −2, −2.5, …, −4.5SD (see A). Corresponding cluster size distributions rapidly deviate from a power law. (E) Avalanches ‘spawn’ new avalanches when lowering threshold z (Δt = constant). Top: nLFP raster period at z = −4.5 SD (nLFP clusters appear ‘columnar’). Middle: Raster of expanded time period from top (broken lines) at z = −3 SD and rescaled for nLFP amplitude (color bar). Note segment A (gray) contains more nLFPs some of which form a new cluster A' (ellipsoid). Bottom: Raster of expanded time period from middle (broken line) for z = −1.5 SD rescaled in amplitude. Spawn of new cluster in B (middle, gray) indicated by B' (ellipsoid).