Figure 4

Morphology of the cerebral organ. a: Overlay image of DAPI nuclear labeling in blue and FMRFamide-like immunostaining in red. a,b: The cerebral organ is attached to the dorsal lobe (dl) of the brain. Its anterior part is innervated by neurites (n) originating from the brain. The remainder of the cerebral organ is filled with densely packed small diameter somata (asterisk) and large diameter cells that contain voluminous cell nuclei (arrowheads). c,d: A canal (arrows) runs along the lateral aspect of the cerebral organ. e,f: In the most ventral part of the cerebral organ this canal opens into a ciliated epidermal canal (arrow) and a sac-like compartment (sc). Here the cells are more slender and densely packed (open arrowheads) than in the wider section of the canal. The duct connects the cerebral organ with the environment (c). bv blood vessel; ci cilia; ecm extracellular matrix; epi epidermis. Scale bars: a,c,e = 40 μm; b,d,f = 100 μm.