Supplementary Figure 2: Connection probability spatial profiles.
From: Synaptic scaling rule preserves excitatory–inhibitory balance and salient neuronal network dynamics
Spatial profiles of connection probability for E-E (a), I-E (b), E-I (c), I-I (d) neurons vs Euclidian distance between neurons (first letter is presynaptic neuron). The number of connections tested is shown in grey. Data points were fitted with a Gaussian function 
with parameters in Supplementary Table 2. (e) The probability of reciprocal connection between E-E neurons (red), E-I (blue) or regardless of their types (black) is not significantly different from the expected probability (dotted lines) that was predicted from the product of unidirectional connections (a-c). (f) Combined connection probability between neurons. (g) Peak connection probability (= connection probability for neurons <350 μm apart) between E neurons (red) and between E and I neurons (E-I and I-E, blue) vs neuronal density. (h) Synaptic delay as a function of distance for excitatory (red) and inhibitory (blue) connections. All data (EPSPs and IPSPs) were pooled and fitted by a linear relation of slope 183 ± 34 μm/ms and intercept 3.55 ± 0.41 ms (95% confidence interval).
