C1 catecholamine neurons form local circuit synaptic connections within the rostroventrolateral medulla of rat

► Phenotypically defined anterograde tracing defines projections of C1 neurons. ► C1 catecholamine neurons in ventrolateral medulla elaborate local circuit axons. ► Axons of C1 neurons arborize throughout the rostrocaudal extent of the C1 column. ► Ultrastructural analysis reveals synaptic contacts between C1 and non-C1 neurons.