Sampling effects and measurement overlap can bias the inference of neuronal avalanches
Fig 4
The signal of an extracellular neuronal recording depends on neuronal morphologies, tissue filtering, and other factors, which all impact the coarse-sampling effect.
In effect, an important factor is the distance of the neuron to the electrode. Here, we show how the distance-dependence, with which a neuron’s activity contributes to an electrode, determines the collapse of avalanche distributions. A: Biophysically plausible distance dependence of LFP, reproduced from [38]. B: Sketch of a neuron’s contribution to an electrode at distance dik, as motivated by (A). The decay exponent γ characterizes the field of view. C–F: Avalanche-size distribution p(S) for coarse-sampling with the sketched electrode contributions. C, D: With a wide-field of view, distributions are hardly distinguishable between dynamic states. In contrast, for spiking activity the differences are clear (light shades in C). E, F: With a narrower field of view, distributions do not fully collapse on top of each other, but differences between reverberating and critical dynamics remain hard to identify. Parameters: Inter-electrode distance dE = 400 μm and time-bin size Δt = 8 ms. Other parameter combinations in Fig B in S1 Text.