The Effects of Optogenetic Activation of Astrocytes on Spike-and-Wave Discharges in Genetic Absence Epileptic Rats

Background: Absence seizures (petit mal seizures) are characterized by a brief loss of consciousness without loss of postural tone. The disease is diagnosed by an electroencephalogram (EEG) showing spike–wave discharges (SWD) caused by hypersynchronous thalamocortical (TC) oscillations. There has been an explosion of research highlighting the role of astrocytes in supporting and modulating neuronal activity. Despite established in vitro evidence, astrocytes’ influence on the TC network remains to be elucidated in vivo in the absence epilepsy (AE). Purpose: In this study, we investigated the role of astrocytes in the generation and modulation of SWDs. We hypothesize that disturbances in astrocytes’ function may affect the pathomechanism of AE. Methods: To direct the expression of channelrhodopsin-2 (ChR2) rAAV8-GFAP-ChR2(H134R)-EYFP or to control the effect of surgical intervention, AAV-CaMKIIa-EYFP was injected into the ventrobasal nucleus (VB) of the thalamus of 18 animals. After four weeks following the injection, rats were stimulated using blue light (~473 nm) and, simultaneously, the electrophysiological activity of the frontal cortical neurons was recorded for three consecutive days. The animals were then perfused, and the brain tissue was analyzed by confocal microscopy. Results: A significant increase in the duration of SWD without affecting the number of SWD in genetic absence epileptic rats from Strasbourg (GAERS) compared to control injections was observed. The duration of the SWD was increased from 12.50 ± 4.41 s to 17.44 ± 6.07 following optogenetic stimulation in GAERS. The excitation of the astrocytes in Wistar Albino Glaxo Rijswijk (WAG-Rij) did not change the duration of SWD; however, stimulation resulted in a significant increase in the number of SWD from 18.52 ± 11.46 bursts/30 min to 30.17 ± 18.43 bursts/30 min. Whereas in control injection, the duration and the number of SWDs were similar at pre- and poststimulus. Both the background and poststimulus average firing rates of the SWD in WAG-Rij were significantly higher than the firing recorded in GAERS. Conclusion: These findings suggest that VB astrocytes play a role in modulating the SWD generation in both rat models with distinct mechanisms and can present an essential target for the possible therapeutic approach for AE

Okuma Performansını Geliştirmede Bilgisayar Yazılımı Kullanımına Yönelik Öğretmen ve Öğrenci Görüşlerinin Değerlendirilmesi

Özel öğrenme güçlüğü ülkemizde özel eğitim alanında en hızlı gelişen kategorilerden birisidir. Akıcı okuma ve okuduğunu anlama gibi beceriler başta olmak üzere özel öğrenme güçlüğü olan öğrencilerin en sık güçlük yaşadıkları alaların başında okuma gelmektedir. Özel öğrenme güçlüğü olan öğrencilerin okuma becerilerini geliştirmede son yıllarda pek çok yöntem ve teknik geliştirilmiştir. Bu yöntemlerden birisi de bilgisayar destekli okuma eğitimidir. Ancak ülkemizde özel öğrenme güçlüğü ve okuma becerisini geliştirmede bilgisayar destekli okuma eğitimine yönelik çalışmaların sayısı sınırlıdır. Bu çalışmanın amacı, TÜBİTAK 113K726 kodlu araştırma projesi kapsamında geliştirilen okuma yazılımına yönelik katılımcı öğretmenlerin ve öğrencilerin görüşlerinin belirlenmesidir. Araştırma sonuçlarına göre, katılımcı öğretmenler geliştirilen bilgisayar yazılımının öğrenci performansı üzerinde olumlu etkisi olduğuna yönelik görüş belirtmişlerdir. Ayrıca, katılımcı öğrenciler okuma becerisine yönelik etkinliklerde geliştirilen yazılımı kullanmayı tercih ettiklerini belirtmişlerdir

Geochemistry of the Turonian-Coniacian strata: New insight into paleoenvironmental conditions of the Tethys, Eastern Pontides, NE Türkiye

The eastern part of the Sakarya Zone, known as the Eastern Pontides, is represented by a south-facing carbonate platform during the Late Jurassic-Early Cretaceous. The shallow marine carbonate sedimentation is masked by hemipelagic sedimentation during the Turonian to Coniacian. The Turonian-Coniacian strata are widely exposed in the Gümüşhane area. In this study, we present new microfacies and geochemical data that can provide new insights into the palaeo-oceanic conditions during the time of their deposition.These strata consist of yellow to gray, thick-bedded, graded calcarenites, calcilutite, pelagic limestone, and monogenic conglomerates. The dominant components are carbonate fragments, including dolomites and limestone, as well as allochthonous bioclasts. Volcanic rock fragments, quartz, cherts, and glauconites are also present, with their abundance varying along the section. The micritic component and planktonic fauna exhibit an increasing abundance in the upward direction, indicating a gradual deepening of the depositional environment. Hence, the analyzed samples can be interpreted as transgressive series deposited on slopes or the deep shelf basin.Furthermore, these strata exhibit distinct V/(V+Ni) and Ni/Co ratios without a notable negative Ce anomaly, suggesting relatively oxygen-reduced conditions. They also show a slight enrichment in alkali elements (Rb and Cs) and post-transition elements (Ga), and LREE, indicating intense weathering. The Ga/Rb and K/Al values further support warm and humid Cretaceous conditions. Thus, the Turonian-Coniacian strata offer valuable information about ancient environments, climate conditions, and the basin evolution of the Tethys Ocean in the Eastern Black Sea region

Sedimentological and geochemical characteristics of Lower Jurassic Sandstones from Gumushane, NE Turkey: implications for source to sink processes, paleoenvironmental conditions, provenance and tectonic settings

The eastern Sakarya Zone (SZ), one of the Alpine Himalayan Belt's main components, has complex Mesozoic-Cenozoic geodynamic evolution, which remains controversial. Early-Middle Jurassic volcano-sedimentary successions (Senkoy Formation) extensively outcrops in Gumushane region, NE Turkey. It is regarded as a critical unit to understand the Mesozoic tectonic evolution of the eastern Sakarya Zone. One of the Senkoy Formation's predominant units is sandstone succession, preserving implications for paleoenvironmental conditions and tectono-sedimentary development of Neotethys Ocean. Thus, a combined analysis of comprehensive petrography, whole-rock major, trace and rare earth element data is carried out on the sandstones, which are well constrained as late Sinemurian- Pliensbachian. The sandstones are mainly arkosic to lithic arenites in lithology showing poor textural maturities. They are mostly represented by relatively high ICV, low CIA, high K2O/Al2O3, Fe2O3+ MgO, TiO2, Th/U, pronounced negative Eu anomaly, enriched LREEs, elevated Gd-N/Yb-N, low Ce/Ce*, Ni/Co, La/V and Zr/Ti. The petrographic and geochemical characteristics imply that the sediments may have experienced relatively low chemical weathering processes and slight reworking and recycling processes with a short transport distance before deposition in the basin. Early Jurassic sandstone successions were interpreted as a transgressive series, showing a predominantly open sea environment with oxidizing paleoenvironmental conditions. The sandstone samples' paleoenvironment is likely to be located along the southern margin of the arc and the Neotethyan basin to the south. The extensional and trans-extensional tectonic regime might have played an essential role in controlling the basin's isolated-half graben and/or asymmetric geometry, leading to changes in the provenance of studied sandstone samples. Thus, the geochemical signature differences are probably associated with basement-related proximal origins and minor effects of the multi-phases petrogenesis that experienced different source to sink processes. Early Jurassic sandstones were probably derived from multi-genetic source rocks, including (i) granite and (ii) metamorphic rocks. Our new data has also indicated that other source rocks can include mafic to felsic volcanic succession. The possible provenance for granitic pluton and metamorphic rocks can be provided by the Hercynian heterogenetic crystalline basement widespread throughout the SZ. However, mafic to felsic volcanic rock source is likely to be associated with the pre-Early Jurassic nearby volcanic-arc, which is rarely recorded in the eastern SZ. The source rock signatures may imply a close genetic link with ancient magmatic-arc generation due to the southward subduction of Palaeotethys

The Effects of Optogenetic Activation of Astrocytes on Spike-and-Wave Discharges in Genetic Absence Epileptic Rats

Background: Absence seizures (petit mal seizures) are characterized by a brief loss of consciousness without loss of postural tone. The disease is diagnosed by an electroencephalogram (EEG) showing spike–wave discharges (SWD) caused by hypersynchronous thalamocortical (TC) oscillations. There has been an explosion of research highlighting the role of astrocytes in supporting and modulating neuronal activity. Despite established in vitro evidence, astrocytes’ influence on the TC network remains to be elucidated in vivo in the absence epilepsy (AE). Purpose: In this study, we investigated the role of astrocytes in the generation and modulation of SWDs. We hypothesize that disturbances in astrocytes’ function may affect the pathomechanism of AE. Methods: To direct the expression of channelrhodopsin-2 (ChR2) rAAV8-GFAP-ChR2(H134R)-EYFP or to control the effect of surgical intervention, AAV-CaMKIIa-EYFP was injected into the ventrobasal nucleus (VB) of the thalamus of 18 animals. After four weeks following the injection, rats were stimulated using blue light (~473 nm) and, simultaneously, the electrophysiological activity of the frontal cortical neurons was recorded for three consecutive days. The animals were then perfused, and the brain tissue was analyzed by confocal microscopy. Results: A significant increase in the duration of SWD without affecting the number of SWD in genetic absence epileptic rats from Strasbourg (GAERS) compared to control injections was observed. The duration of the SWD was increased from 12.50 ± 4.41 s to 17.44 ± 6.07 following optogenetic stimulation in GAERS. The excitation of the astrocytes in Wistar Albino Glaxo Rijswijk (WAG-Rij) did not change the duration of SWD; however, stimulation resulted in a significant increase in the number of SWD from 18.52 ± 11.46 bursts/30 min to 30.17 ± 18.43 bursts/30 min. Whereas in control injection, the duration and the number of SWDs were similar at pre- and poststimulus. Both the background and poststimulus average firing rates of the SWD in WAG-Rij were significantly higher than the firing recorded in GAERS. Conclusion: These findings suggest that VB astrocytes play a role in modulating the SWD generation in both rat models with distinct mechanisms and can present an essential target for the possible therapeutic approach for AE

The relationship between problematic internet use, sleep quality and impulsivity in adolescents with major depressive disorder

Objective: Problematic internet use and poor sleep quality are widespread problems in adolescents. The aim of this study is to investigate the relationship between problematic internet use, sleep quality and impulsivity in adolescents diagnosed with major depressive disorder and to compare the findings with those of healthy controls. Methods: The study was planned as a single-disciplinary, three-centered, cross-sectional study with a control group. All participants were assessed using the Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version (K-SADS-PL). Beck Depression Inventory (BDI), Barratt Impulsiveness Scale (BIS-11), Pittsburgh Sleep Quality Index (PSQI) and Young's Internet Addiction Test (IAT) were administered to all participants. Results: It was determined that the total scores of BIS-11 scale, PSQI and IAT were statistically and significantly higher in the depression group than controls. In addition, a positive correlation was found between IAT and BIS-11 score and between IAT and PSQI. A positive correlation was also found between BIS-11 and PSQI. Conclusion: According to the findings of our study, it is suggested that there may be multiple and complex interactions between problematic internet use, low sleep quality, impulsivity and depressive symptoms

Geochemical characteristics of Late Jurassic-Early Cretaceous platform carbonates in Hazine Mağara, Gümüşhane (NE Turkey): Implications for dolomitization and recrystallization

Late Jurassic-early Cretaceous Berdiga Formation of the Eastern Pontide, Turkey represents a carbonate platform succession comprised of pervasivly dolomitized intra-shelf to deep shelf facies. In this area, polymetallic deposits occur as veins and lenses within the Berdiga Formation in close proximity to its upper contact with the overlying formation. Three different types of replacive dolomites occur in the formation: 1) microcrystalline dolomite (Md Dolomite); 2) fabric-preserving dolomite (Fpd Dolomite), and 3) fabric-destructive dolomite (Fdd Dolomie). Replacive dolomites are Ca-rich and nonstoichiometric (Ca56-58Mg42-44) and are characterized by a pronounced negative shifts in oxygen (–11.38 to –4.05 ‰V-PDB), 13C values of 0.69 to 3.13 ‰V-PDB, a more radiogenic 87Sr/86Sr ratios (0.70753 to 0.70884), extremely high Fe (2727-21053 ppm) and Mn (1548-27726 ppm) contents. All dolomite samples have low Y/Ho ratios (23 to 40) and they also contain highly variable contents of REE (7 to 41). REE patterns of dolomites normalized to PAAS show distinct positive Eu anomaly (1.3 to 2.1) and slightly flattened Ce anomalies (0.8 to 1.1). Integration of petrographic and geochemical studies reveal the history of a variety of diagenetic processes highly affected by hydrothermal alteration, which include dolomitization, recrystallization, dissolution, silicification and pyrite mineralization associated with the emplacement of the polymetallic mineralization.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Attachment, emotion regulation and anger expression in adolescent depression: Did comorbid anxiety disorder not have a role?

Depression is a common mental health problem in adolescence. In this study it was aimed to investigate attachment properties, emotion regulation skills and anger expression patterns in adolescents diagnosed with major depressive disorder (MDD) and to compare the results with healthy controls' findings. Effects of having comorbid anxiety disorder (AD) to these psychological properties were also evaluated. The study was planned as three-centered, single-disciplinary, a cross-sectional study with a control group in Turkey. Depression group was consisted of 97 adolescents while control group was 101 adolescents. All participants were administered Beck Depression Inventory (BDI), Inventory of Parent and Peer Attachment (IPPA), Difficulties in Emotion Regulation Scale (DERS), and State-Trait Anger Expression Inventory (STAXI). Depression group had statistically lower scores in peer attachment and parent attachment, and higher scores in all subscales of DERS compared to the controls. Due to STAXI, it was observed that depression group obtained statistically significant higher scores in trait anger, repression of anger, expression of anger and statistically lower scores in control of anger, compared the controls. There was no difference in state anger between groups. In depression group, there were no significant differences for any promising psychiatric properties between adolescents with MDD and those with MDD + AD. The findings of this study supported that anger expression and emotional regulation difficulties were related with depression and that this relationship was also associated by attachment security. These findings are important for clinical practice to increase understanding of the association between attachment security, emotion regulation, anger expression and depression