Patterns of Arrangement and Connectivity in the Central Nervous System of Arachnids

Fine Structure of the Neuroganglia in the Central Nervous System of the Harvestman Leiobunum japonicum (Arachnida: Opiliones)

“…The supraesophageal ganglion of all arthropods was through to include three components -protocerebrum, deutocerebrum, and tritocerebrum. Previous studies have also shown that the chelicerate animals only have two units in the supraesophageal ganglion due to loss of the first antenae and deutocerebrum (Babu, 1985;Weygoldt, 1985). However, developmental genetic research on spiders (Damen et al, 1998) and mites (Telford & Thomas, 1998) revealed that the chelicerae and cheliceral ganglion are homologous to the first antennae and duetocerebrum of other arthropods, and that no segmental components are missing in the chelicerae CNS (Mittmann & Scholtz, 2003).…”

“…However, developmental genetic research on spiders (Damen et al, 1998) and mites (Telford & Thomas, 1998) revealed that the chelicerae and cheliceral ganglion are homologous to the first antennae and duetocerebrum of other arthropods, and that no segmental components are missing in the chelicerae CNS (Mittmann & Scholtz, 2003). The optic masses of arachnids are poorly developed compared to insects or crustaceans, and these are exists as small masses of neuropile without any particular specialization (Babu, 1985). Although the segmentation of the arachnid brain is still not clear, it is generally accepted by the researchers of this area that the important and complex neuropile masses in arachnids are located in the protocerebrum of the supraesophageal ganglion.…”

“…The purpose of the present investigation was to determine the electron-microscopic features of neurons and neuroglial cells in the CNS ganglia, as part of a wider investigation into the nervous centers and pathways associated with nerve terminations and plexuses. The application of electron microscopic techniques to the study of invertebrate CNS has revealed that the shape and arrangement and their connections with the brain and other ganglia suggest that they are associated with complex behavioral activities (Babu, 1985). In spite of drastic differences in the appearance of harvestmen and other arachnid CNS ganglia, the nature of the nerve cells in the ganglion is of particular interest, not only because of their functional importance in the transmission of stimuli but also because of their possible association with the significant nerve fiber population in the ganglion (Chiarodo, 1968).…”

“…Following fine work of the arachnid CNS (Babu, 1975), several other workers (Babu, 1985;Babu & Barth, 1984;Doeffinger et al, 2010;Hill, 2006;Hwang & Moon, 2003;Park et al, 2013;Weltzien & Barth, 1991;Weygoldt, 1985) have reported structural organization of the CNS of arthropod animals. However, most of our anatomical and histological understandings of Opilione CNS comes from only a few authors (Shultz & Pinto-da-Rocha, 2007).…”

Microstructural Organization of the Central Nervous System in the Orb-Web Spider Araneus ventricosus (Araneae: Araneidae)

“…However, there are unique characteristics in spider's nervous system, not shared by insects and crustaceans (Babu, 1985;Weygoldt,1985). Arachnids are distinguished from insects by the fact they have eight legs and have no antennae or wings.…”