V. S. Gorelkin

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.

Functional role of leg receptors of the cockroach Periplaneta americana in the system of walking control

This work deals with study of role of the hairplate and of campaniform sensillae (CS) on legs of the cockroach Periplaneta americana in the system of walking control. Three receptors were shown to induce their regulatory, correctional effect on the rhythm of the cockroach steps depending on the external circumstances. These effects are mainly realized only at slow walking.

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.

Functional Role of Dragonfly Legs before and after Wing Formation: Rearrangement of Coordinatory Relationships

We report here our studies of the characteristics of the structural-functional organization of the leg apparatus of the dragonfly Aeshna grandis, in larvae of the final instar, whose legs have a locomotor function, and in adult winged individuals (imagoes), whose legs have lost their locomotor function and are used mainly as traps to catch prey in the air. Neither the shape nor the proportions of individual leg segments in imagoes were significantly different from those in larvae, and all changes in the functional role of the legs in imagoes occur as a result of changes in the mechanisms controlling the functioning of the leg muscles and the corresponding rearrangements in coordinatory relationships. These rearrangements, as evidenced by the data reported here, affect the mechanisms generating motor commands, the appearance of a tight correlation in the operation of the wing muscles and the leg apparatus, and various others. These mechanisms are discussed.

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.

Role of central and peripheral mechanisms in control of excitability of segmental motor centers in insects

The role of central and peripheral mechanisms in control of excitability of segmental centers providing different motor acts in insects of phylogenic close orders, but differing by the level of activity of their locomotor systems has been studied in the locust Locusta migratoria and the cockroach Periplaneta americana. It was shown that the level of relative excitability of segmental centers in cockroaches seemed to be much determined by the peripheral mechanisms, but not by the central mechanisms as in locust. It is suggested that control of activity of segmental locomotor centers from the higher parts of CNS can be realized by different ways: predominantly via excitatory or inhibitory influences on activity id some particular locomotor systems depending on their role and significance in motor behavior of these animals.

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.

Change of Activity of Locomotor Centers of the Locust Locusta migratoria under Effect of Increased Gravitation

The work studies effects of elevated gravitation on activity of locomotor centers in the locust Locusta migratoria L. Under effect of the increased gravity field the excitation of the motor centers that provide activity of the locus wing apparatus was shown to decrease. Analysis of the data obtained has allowed us concluding that the higher CNS centers (subesophageal ganglion) produce at least two types of excitatory (stimulatory) effects on segmental centers, one of the types affecting motor centers in the rest state, the other, in the active state. We believe that it is the impulses of the second type that are inhibited under effect of the increased radial acceleration on the organism. There is every reason to think that an important role in these processes is played by peculiar structures of the supraesophageal ganglion protocerebrum: mushroom bodies and the central complex that regulates activity of the locust segmental centers both directly and indirectly via the subesophageal ganglion.