Fig. 1. Relationship between models and possible computations in cortical circuits, and proposed strategy for connectomic model distinction in local circuit modules of the cerebral cortex.

a Relationship between computations suggested for local cortical circuits (left) and possible circuit-level implementations (right). Colored lines indicate successful performance in the tested computation; gray lines indicate failure to perform the computation (see Supplementary Fig. 1 for details). b Enumeration of candidate models possibly implemented in a barrel-circuit module. See text for details. c Flowchart of connectomic model selection approach to obtain the posterior p (m|C) over hypothesized models m given a connectome C. ABC-SMC: approximate Bayesian computation using sequential Monte–Carlo sampling. d Sketch of mouse primary somatosensory cortex with presumed circuit modules (“barrels”) in cortical input layer 4 (L4). Currently known constraints of pairwise connectivity and cell prevalence of excitatory (ExN) and inhibitory (IN) neurons ($p_{ee}$: pairwise excitatory-excitatory connectivity^30–33,36, $p_{ei}$: pairwise excitatory-inhibitory connectivity^31,33, $p_{ii}$: pairwise inhibitory-inhibitory connectivity^31,34, $p_{ie}$: pairwise inhibitory-excitatory connectivity^31,33,35, $r_{ee}$: pairwise excitatory-excitatory reciprocity^30,31,33).