Table 2.

Sparseness (p) and fraction of bidirectional connections relative to random (R) in the different models

Model	p	R
ER bidirectional	$p_{\text{bid}}+\frac{p_{\text{uni}}}{2}$	$\frac{1}{p^2}{p}_{\text{bid}}$
Clusters	f+p+ + f−p−	$\frac{1}{p^2}\left(f_{+}{p}_{+}^2+f_{-}{p}_{-}^2\right)$
Distance	〈p(r)〉	$\frac{1}{p^2}\langle p^2\left(r\right)\rangle$
Degree	$\frac{\langle K\rangle }{N}$	$\left(1+\rho \frac{\sqrt{{\sigma }_{\text{in}}^2{\sigma }_{\text{out}}^2}}{{\langle K\rangle }^2}\right)$

In the models with clusters f₋ = 1 − f₊ and f₊ is the fraction of neuronal pairs that are in the same cluster. The brackets 〈 〉 in the Dis model represent averages over the distribution of distances in the network. See the main text for a description of the other parameters.