Wyniki wyszukiwania - Biblioteka Nauki

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Ilustrowany zarys dziejów ceramiki Wyżyny Armeńskiej. Historia ceramiki ormiańskiej w pigułce

100%

Ghazaryan A.

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tom R. 64, nr 3

34--35

PL

Na Wyżynie Armeńskiej, usytuowanej w północno−zachodniej części Azji Mniejszej, produkcja ceramiki zaczęła się rozwijać w odległej przeszłości. Na stosunkowo niewielkim terytorium Armenii można dziś prześledzić wszystkie etapy jej rozwoju − od najbardziej archaicznych do wykorzystania sprzętu sztalugowego. Technologia produkcji ceramiki armeńskiej jest niezwykle zróżnicowana i złożona. Do dziś zachowane są tradycje ceramiki prawie wszystkich okresów historycznych, co pozwala odtworzyć dawne metody przetwarzania surowców oraz wykonywania i wypalania naczyń. Wyroby ceramiczne dobrze charakteryzują życie ludzi, ich kreatywność, a co za tym idzie styl epok historycznych.

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Attentional beta activity during visual processing

51%

Ghazaryan A. , Bekisz M. , Sala J. , Wrobel A.

Acta Neurobiologiae Experimentalis

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2003

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tom 63

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nr 5

3

Effect of extra high power pulses and hydrogen peroxide on functional activity of neurons

51%

Hakobyan K. , Hunanyan A. , Ghazaryan A. , Ayrapetian S.

Acta Neurobiologiae Experimentalis

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2009

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tom 69

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nr 3

EN

It was recently shown that the exposure of aqueous solutions to highpeak-power microwave pulses leads to the formation of hydrogen peroxide (H202). The aim of this study was to evaluate the effects of extra high power pulses (EHPP,9.3 GHz, 101.2 kW/kg) millimeter waves and H202 on action potentials, acetylcholine chemosensitivity and cell volume of giant neurons from the parietal ganglion of Helix Pomatia by means of standard voltage-clamp method. H202 containing and EHPP treated physiological solutions increased the interburst period of neuronal pacemaker activity. In K-free physiological solution (when Na+ /K+ pump is inactive) the interburst period was higher than in normal one. Application of H202 containing and EHPP treated physiological solutions changed the number of active receptors on neuromembrane surface which caused depression of its chemosensitivity and decreased as a consequence of cell volume (cell shrinking). These comparative studies allowed us to suggest that EHPP induced formation of H2O2 is one of the main messenger through which the non-thermal biological effect of EHPP on functional activity of neurons is realized.

4

The phenotype of newly generated cells in the adults' brain of some species of rhinolophidae

51%

Ghazaryan A. , Djavadian R. , Yavrouyan E. , Turlejski K.

Acta Neurobiologiae Experimentalis

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2009

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tom 69

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nr 3

EN

In the brain of adult mammals neurogenesis continues in two regions: the dentate gyrus (DG) and subventricular zone of the lateral ventricles (SVZ). Here we present data concerning neurogenesis in brains of Rhinolophus (Rh) ferrumequinum, Rh euryale, Rh mehely and Rh hipposideros. These bats were captured on permission of the Ministry of Environment of Armenia. After capture all bats were injected with bromodeoxyuridine (BrdU, 300 mg/kg). Seven to nine days later animals were perfused transcardially with 4% paraformaldehyde in narcosis. We used immunohistochemical double-labeling to characterize the phenotype of newly generated cells. Colocalization of BrdU with NeuN (marker of mature neurons), glial fi brillary acidic protein (GFAP, astrocytic marker) and 2`,3`cyclic nucleotide phosphatase (CNP, oligodendrocytic marker) was examined using confocal microscope. We found that in both neurogenic regions the rate of neurogenesis was highest in Rhinolophus ferrumequinum and lowest in Rh mehely. Double-immunolabeling showed that in all neurogenic regions of the bats’ brain the neuronal phenotype dominated among newly generated cells, while proportion of astrocytes was low. BrdU colocalized with CNP in only a few cells in the SVZ of Rh ferrumequinum. We suggest that the rate of neurogenesis in different species may depend on the bats’ ecology.

5

Spatio-temporal receptive field structure and direction preference of neurons in eat's superior colliculus

45%

Wypych M. , Ghazaryan A. , Borkowski W. , Wrobel A. , Waleszczyk W. J.

Acta Neurobiologiae Experimentalis

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2005

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tom 65

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nr 3

6

Stimulus-driven and anticipatory attention differentially modulate primary visual cortex

38%

Bekisz M. , Bogdan W. , Ghazaryan A. , Waleszczyk W. J. , Kublik E. , Wrobel A.

Acta Neurobiologiae Experimentalis

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2015

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tom 75

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nr Supl.

EN

Only a fraction of the visual information can be consciously processed. The mechanism by which stimuli are selected for mindful processing is based on current behavioral situation and involves selective attention. Attention can be focused either volitionally by anticipatory signals, derived by task demands, or automatically by bottom-up signals from salient stimuli. Since brain mechanisms underlying these two processes of attention, are poorly understood, we performed electrophysiological experiments with chronic recordings from visual cortex of behaving cats engaged in delayed visual and auditory spatial discrimination task. Our previous results showing that both attentional tasks were accompanied by enhanced activity in beta frequency band in visual cortical areas 17 and 18 led us to the hypothesis that beta signals serve as attention carrier. We have now searched whether attention-related beta activity would influence cortical responses to electrical peripheral stimulation. We compared potentials (EPs) evoked by the optic chiasm stimulation in primary visual cortical areas during ongoing high or low amplitude beta signals. Under anticipatory attentional task peripheral stimuli preceded by a 200 ms high-amplitude beta signals evoked larger amplitude EPs as compared to those which followed low-amplitude beta activity. In contrast, during bottom-up attentional condition cortical EPs preceded by high beta oscillation, were on average smaller than those following low beta signals. Correlation analysis between beta signals at different recording sites showed that bottom-up task activated cortical beta frequency maps in a mosaic-like pattern whereas anticipatory modulation resulted in spatially homogeneous beta excitation. Taken together, our results suggest that enhanced beta activity during the two attentive conditions shape the functional organization of cortical networks into substantially different spatial patterns.