Origin, destination and mapping of tritocerebral neurons of locust.

The connectivities of the tritocerebrum of locust (Locusta migratoria L., Schistocerca gregaria (Forsk.)) were studied histologically and by means of cobalt chloride infusion. Its neuropil consists partly of fibers which traverse the tritocerebrum and areas consisting of neuropilar agglomerizations ("glomeruli"). The following direct connections between the tritocerebrum and other regions were observed: connections to 1) dorsal and lateral brain regions (mushroom body, optic lobe), 2) the ventral nerve cord, 3) the stomatogastric nervous system (here the protocerebrum and the subesophageal ganglion are also involved in these connections), 4) the retro-cerebral glands (corpora cardiaca, corpora allata), and 5) muscles of the foregut.