Fig. 1

Scenarios of feedforward connectivity of motor networks and the expected pairwise correlation. a Traditional half-center model with feedforward connections from a common drive network (yellow shaded area) to flexor- and extensor–related neurons in the spinal cord (blue shaded region with local premotor neurons in gray) including reciprocal inhibition (IN). The common–drive network of unknown size and architecture projects to functionally related local neurons in the lumbar spinal cord (blue shaded region). b A densely connected input from the common–drive network consisting of few neurons with many connections per neuron (high out–degree) results in strongly correlated input across the receiver neurons (blue). c A sparsely connected and large common–drive network with small out–degree results in weak correlation across the receiver neurons. The number of connections coming into the receiver network (the in–degree distribution) is the same as in b