ИСТИНА

Neodermata is a monophyletic group of Platyhelmintes and includes major groups like the monogeneans, digenean trematodes and eucestodes, and some minor groups. Comparative brain morphology have been studied in several species by ultrastructural and immunocytochemical methods. The neodermata brain consists of paired cerebral ganglia, connected by the wide commissure, from which extend paired anterior nerves and two posterior main nerve cords. Brain is composed of numerous serotoninergic, peptidergic and cholinergic immunoreactive neurons. Monogeneans and digenean trematodes have the bilateral symmetrical bilobed brain with the broad commissure positioned dorsally behind the pharynx. The amphilinidean brain consists of the right and left non-symmetrical ganglia connected by the median commissure located ventrally underneath the anterior pit. Cestodes’ brain has complicated architecture. More prominent concentrations of neurons locate around the median commissure and two main neuropils. Scoleces with four sets of attachment organs have distinct double lateral lobes with two pairs of main neuropils. The central unpaired lobe with neurons, neuropil, and the X(or+)-shaped commissure was found in the brain of several species. The structure of the anterior nerves and frontal ganglia is a specific feature of the brain architecture for different neodermata taxa. Anterior nerves and ganglia innervate the mouth, pharynx, lappets, musculo-glandular organs in monogenea and trematoda; and suckers, proboscises, glandular organs in cestodes. The bilobed neuropil is a most compact integrative part of the neodermata brain. It has the fibrillar and glial envelope in many species and contains synapses. The architecture and ultrastructure of the brain neuropil is different in neodermata. The number of the neuropils in the brain correlates directly with the number of the lobes; and each ganglion has its own neuropil. The evolutionary trend of the brain architecture is discussed.