V. L. Svidersky

On structural-functional organization of dragonfly mushroom bodies and some general considerations about purpose of these formations

Anatomy as well as (for the first time) the fine structure have been studied of the mushroom bodies located in protocerebrum of the supraesophageal ganglion of dragonflies—the most ancient flying insects on Earth. Used in the work are larvae of the last age (prior to winging), in which the mushroom body structure has already been completely formed and corresponds to that in imago. The total organization of the dragonfly mushroom bodies has been established to be more primitive than that of other insects studied so far. This involves both the number of interneurons (Kenyon cells) present in the mushroom bodies and the character of anaptic connections formed by these cells. There is confirmed the absence in dragonflies of the mushroom body calyces that in opinion of some authors are obligatory “input gates” into these structures. Peculiarities of the neuropil structure in the area of the absent calyces are studied in detail. For the first time in insects there are revealed the direct (without additional synaptic switching) pathways forming the “afferent input” from optic lobes into the mushroom body calyx area. Also detected are the direct pathways going from the mushroom bodies to the abdominal chain (“efferent output”). A possible functional significance of these findings as well as the general role of mushroom bodied in control of some forms of insect behavior are discussed.

Tasks and perspectives of development of evolutionary physiology

The paper considers the main tasks facing evolutionary physiology as well as the methods that allow these tasks to be solved. It is shown that alongside with traditional, classical methods (phylogenetic, ontogenetic, experimental, clinical), there developed and got recognition in the present-day evolutionary physiology principally new methodological approaches important for solution of actual problems of this discipline. It is the method of mathematical modeling of functions, which makes it possible not only to study on the model, in temporary scales convenient for analysis, evolution of the given functions under the given actions, but also to model the evolutionary process itself in its different manifestations. It is the method of gene engineering that allows studying processes of formation of specific functional systems, their interaction and “mutual adjustment” at the organism level. It is lastly the method of tissue cultures allowing reconstruction under artificial conditions various systems of organism and study of regularities and mechanisms of morphogenesis and formation of functions. The paper discusses trends of development of evolutionary physiology for the last few years, considers perspective directions of studies, using specific examples, and shows possible ways for practical applications of fundamental investigations in the field of evolutionary physiology.

Structural-functional peculiarities of the wing apparatus of insects that do not have and do have the maneuvering flight

The work considers character of behavior in flight and discusses peculiarities of structural-functional organization of the wing apparatus of two representatives of insects—the migratory Asian locust Locusta migratoria (a low-maneuvering insect) and the dragonfly-darner Aeshna sp. (an insect able to perform complex maneuvers in air). The main principles underlying the insect wing apparatus activity are considered and the mechanisms allowing the dragonflies to perform complex maneuvers in the flight are analyzed in detail.

Insects and Vertebrates: Analogous Structures in Higher Integrative Centers of the Brain

This work deals with studies on anatomical relationships, neuronal composition, and some synaptic connections that exist in the central complex (CC) in the supraesophageal ganglion in larva of dragonfly g. Aeschna. It has been shown that CC contains protocerebral bridge of an elongated and slightly curved cylindrical shape, fan-shaped and ellipsoid bodies of a bean-like shape and two small roundish noduli. There were revealed (stained) neurons providing both internal connections of CC and its connections with other CNS regions. Connections with tritocerebrum, the higher center of the autonomic nervous system, and subesophageal ganglion, an intermediate “relay” between supraesophageal ganglion and truncal brain, have been established. The existence of connections of CC with nuclei of abdominal nervous chain is suggested. Connection of ocelli with the CC has been traced. Unipolar neurons of the same type have been revealed, each of them giving collaterals to protocerebral bridge and ending as bushy terminals that form the main part of glomerule in the fan-shaped and ellipsoid bodies. Glomeruli are arranged in rows, in which cross connections have been found. It has been established that the structure of neuropils of the fan-shaped and ellipsoid bodies represent a shielding structure described in the cerebral cortex, midbrain cortex, and cerebellar cortex of vertebrates. Thus, in insects, like in vertebrates, the shielding structures developed not only in optic centers, but also in structures performing higher integrative functions. A possible functional role of the central complex is discussed.

Effect of static load on motor behavior of the cockroach Periplaneta americana

Effect of static load on activity of motor centers controlling motor activity (walking, flight) was studied in the American cockroach Periplaneta americana L. It has been established that under effect of load on the animal body the relative excitability of these centers increases. A suggestion is put forward about the presence of common neuronal elements in the generator networks providing motor acts in the American cockroach; a role of afferent systems in control of excitability of loco-motor centers functioning in the regime of static load is shown.

Peculiarities of structural-functional organization of the motor neuropil in the dragonfly thoracic ganglia

The study considers structural-functional relations in motor neuropil of the thoracic ganglia in dragonflies-insects capable of performing very complex and fast maneuvering in flight. The motor neuropil in dragonflies was shown to be more differentiated than in less mobile insects, while its motor nuclei are more outlined and approached to each other. There were revealed dendrites of the leg muscle motoneurons (intermediate nucleus), running to the anterior and posterior nuclei that contain dendrites of the wing muscle motoneurons. A possible role of such a dendrite approaching is discussed for close functional cooperation of wing and leg muscles essential for dragonflies to catch a large prey in flight by using their legs. Peculiarities of structural organization of the wing muscle motoneurons in dragonflies and locusts are considered to suggest the greater functional capabilities of motoneurons in the dragonfly motor apparatus.

Orbeli and Evolutionary Physiology

A brief history of evolutionary physiology and the role in its foundation of the outstanding physiologist of our country, Leon Abgarovich Orbeli, are reviewed. The main stages of development of evolutionary physiology are described; the difficulties occurring in the path of its establishment are noted. It is shown that the establishment of evolutionary physiology as an independent scientific discipline was far from occurring at once; its foundation required many years of pondering, an intensive organizational work, and the great personal courage of L.A. Orbeli. It is narrated how the main (pivotal) and other important tasks of evolutionary physiology were developed, what methodological principles were used, how Orbelis school appeared.

Motor activity of infusoria: Theoretical and applied aspects

The article considers morpho-functional organization of cilia—the infusorian locomotion organs—and shows a great complexity of motor behavior of these unicellulars. The problem of control of locomotor activity of infusorian as the single organism is discussed, and the conclusion is made that the system of control of movements is to be multilevel and to include receptor, afferent, central, efferent, and effector links. The role of central integrator and coordinator of motor behavior can be played by the cell nucleus (macronucleus) closely connected with periphery by cytoskeleton dynamic elements. The problem of fight with infusoria parasitizing in the human and animal bodies by impairing motor activity of these unicellulars is also discussed.

Peculiarities of ultrastructural organization of the metathoracic ganglion in the locustLocusta migratoria larva

In electron microscopic study of structural organization of the thoracic ganglion of the locust larva of the 1st age (1–2 days after hatching), the data on the structure of motoneurons of the 1st nerve, basal and motor neuropil of the larva were obtained. The effector elements of the larval locust CNS are formed rather early and have the structural plan similar to that in adult insects. However, in the larval motoneurons innervating the flight muscles (longitudinal dorsal muscles, wing depressors) the clearly seen features of immaturity of these nervous elements are revealed. Study of the larval ganglion neuropil has shown that the basal neuropil is morphologically formed sufficiently completely as early as in larvae of the first days after hatching. There are shown longitudinal contacts between axons of the ventral neuropil zone, the presence of axons forming theen-passant contacts as well as the synapses with a heterogeneous set of vesicles in the presynaptic area. The presence of the great number of granular vesicles in the basal neuropil of the locust larva may indicate an important role of catecholamines in the early development of the nervous system in the locust larva.