Prof. Levon Manvelyan

Head of Laboratory
Corresponding member of NAS RA

E-mail: lmanvel@physiol.sci.am

In 1988 L.R. Manvelyan defended his thesis earning the degree of doctor of biological sciences in human and animal physiology. Title of Dissertation: “Neuronal integration mechanisms of the facial nerve”. He has 120 scientific publications. Author of a monograph titled: “Neuronal organization of the facial nerve nucleus”.

The main direction of scientific activities in the laboratory of CNS focuses on the comperative physiological study of movement activity control in the organism. The uniqueness of the vestibular and cerebellar nuclei of amphibians is their significant modification in response to the environmental changes (partial or complete transition to land) and development of tetrapod body. Representinq the early stage of development of taillesses, amphibians have the least differentiated vestibular-cerebellar structures among the tetrapods. However, at an early stage, the vestibular nuclear complex represents the central structures, integrating signals from the labyrinth, cerebellum, spinal cord and reticular formation.

On the basis of experiments conducted over the last decade some original results were received. EPSPs were recorded intracellulary in response to vestibular nerve stimulation. They underwent a following transformation into action potentials and had mono- or polysynaptic nature.

It is shown, that the cervical and lumbar neurons of spinal cord in frog’s VNS, as sources of vestibulo-spinal fibers, are distributed separately or more often in small groups which leads to patch-like somatotopy, but not to the formation of well-distributed zonal somatotopy as it is observed in mammalian VNS.

The vestibular nerve stimulation evoked chemically transmitted mono- and polysynaptic potentials with orthodromic action potentials in the neurons of medial reticular formation.

In frog brainstem perfusion experiments intracellular potentials of VNS neurons in response to the stimulation of ipsilateral auricular lobe of the cerebellar cortex were studied. It was established that stimulation of the last evoked mono- and polysynaptic inhibitory postsynaptic potentials in the VNS neurons.

Currently experiments are being conducted to study the effect of auricular lobe of cerebellum onto the neurons of Reticular Formation.