adult retrocerebral organ complex (ROC) Fig. 14-5, Fig. 14-16, Fig. 14-17, in Biology of Ticks ISBN:0-19-505910-7. TADS:0000237 TADS:0000237 The retrocerebral oran complex is a major neurohaemal organ located in a neurohaemal sinus that connects with the periganglionic sinus around the synganglion. The ROC is located immediately above the posterior dorsal region of the supraesophageal region of the synganglion. The ROC consists of an unpaired dorsal lobe and paired ventral lobes. Regarded as an important neurohaemal organ but its precise role remains uncertain. default_namespace adult neurohaemal organ compound organ