Adám Deák

Publications of Adám Deák

• Effect of unilateral labyrinthectomy on the molecular composition of perineuronal nets in the lateral vestibular nucleus of the rat.

  Authors: Adám Deák, Tímea Bácskai, Botond Gaál, Eva Rácz, Klara Matesz

  Neuroscience letters. 02/2012; 513(1):1-5.

  Disturbances in vestibular functions caused by unilateral labyrinthectomy (UL) are spontaneously restored during the process of vestibular compensation due to the plasticity of CNS. The underlyingDisturbances in vestibular functions caused by unilateral labyrinthectomy (UL) are spontaneously restored during the process of vestibular compensation due to the plasticity of CNS. The underlying molecular background of vestibular compensation is not yet fully understood. Recent studies have shown that the extracellular matrix (ECM) molecules have either permissive or non-permissive effect on the neural plasticity. In our previous study we have demonstrated changes in the expression of hyaluronan (HA) in the vestibular nuclei (VN) of the frog following peripheral vestibular lesion. The present work was undertaken to examine the expression of the HA and chondroitin sulfate proteoglycans (CSPGs) in the lateral vestibular nucleus (LVN) of the rat following UL by using histochemical methods. On the first postoperative day, the condensation of the ECM around the neurons, the perineuronal net (PNN) was not distinguished from the surrounding neuropil on the side of UL indicating the desorganization of its molecular structure. At survival day 3, the PNN was recognizable with the HA probe, whereas its staining for the CSPGs was restored by the time of the seventh postoperative day. In the neuropil, the intensity of the HA increased on the operated side, while the CSPGs reaction almost completely disappeared. The present study have demonstrated for the first time that the UL is accompanied by the modification of the HA, and CSPG staining pattern in the PNN of the LVN in the rat. As the reorganization of the PNN corresponds to the restoration of spontaneous activity of vestibular neurons, our study implies the role of HA and CSPGs in the vestibular compensation.

• Vestibular afferents to the motoneurons of glossopharyngeal and vagus nerves in the frog, Rana esculenta.

  Authors: Adám Deák, Tímea Bácskai, Gábor Veress, Clara Matesz

  Brain research. 07/2009;

  The aim of this work was to study whether the vestibular afferent fibers establish direct connections with the motoneurons of glossopharyngeal and vagus nerves of the frog, Rana esculenta. InThe aim of this work was to study whether the vestibular afferent fibers establish direct connections with the motoneurons of glossopharyngeal and vagus nerves of the frog, Rana esculenta. In anaesthetized animals the vestibulocochlear nerve and the common root of glossopharyngeal-vagus and accessory (IX-X-XI) nerves were simultaneously labeled with fluorescein dextran amine (vestibulocochlear nerve) and tetramethylrhodamine dextran amine (IX-X-XI). With a confocal laser scanning microscope we could detect close appositions between the vestibular afferent fibers and somatodendritic components of the general and special visceral motoneurons of the ambiguus nucleus of IX-X nerves. The direct impulse transmission may provide a quick and immediate response of cardiovascular and gastrointestinal system upon body displacement.

• Vestibulotrigeminal pathways in the frog, Rana esculenta.

  Authors: Clara Matesz, Gabriella Kovalecz, Gábor Veress, Adám Deák, Eva Rácz, Tímea Bácskai

  Brain research bulletin. 04/2008; 75(2-4):371-4.

  The aim of this study was to investigate whether primary vestibular afferent fibers establish direct connections with the motor and sensory trigeminal system in the brainstem of the frog. TheThe aim of this study was to investigate whether primary vestibular afferent fibers establish direct connections with the motor and sensory trigeminal system in the brainstem of the frog. The experiments were carried out on Rana esculenta. In anaesthetized animals the trigeminal and vestibular nerves were prepared, and their proximal stumps were labeled either with fluorescein binding dextran amine (trigeminal nerve) or tetramethylrhodamine dextran amine (vestibulocochlear nerve). With a confocal laser scanning microscope we could detect close connections between the vestibular fibers and branches of the dorsal dendritic array of the jaw-closing motoneurons, suggestive of monosynaptic contacts. In the other parts of the brainstem, vestibular terminals were detected in the termination areas of the mesencephalic trigeminal nucleus and of the Gasserian (Vth) ganglion and they were probably involved in polysynaptic connections. In agreement with the results obtained in mammalian species, the present findings suggest that the vestibulotrigeminal relationship is quite complex and uses multiple pathways to connect the vestibular apparatus with the motor and sensory nuclei of the trigeminal nerve in the anurans as well.