Fig. 8

The possible neuronal mechanisms underlying the organizing pattern wherein the inspiratory motor activities in the rostral thoracic segments are larger than those in the caudal thoracic segments. a The pattern is organized at the level of medulla where descending neurons exist. The descending neurons project richly to the motoneurons positioned at more rostral thoracic cord. b An example showing that the pattern is organized at the level of the spinal cord. In this example, the number of inspiratory excitatory interneurons is larger than that in the rostral segments, and these neurons amplify the excitatory inputs to the motoneurons in the rostral segments