Morphometric analysis of supraoptic neurons of the rat hypothalamic nuclei under conditions of prolonged illumination

The article reviews the results of studies of the morphofunctional state of neurons of the supraoptic nuclei of the rat hypothalamus under conditions of different duration of light regime. Under standard light regime in rats, a diurnal rhythm of morphofunctional activity of supraoptic nucleus neurons with maximum activity during daytime (before 2 p.m.) is recorded. In animals subjected to prolonged light exposure, more pronounced changes in the morphofunctional state of the supraoptic neurons of the hypothalamus at 2 a.m. than at 2 p.m. were established. Thus, the neuronal nucleus area was 94.08 ± 9.55 μm2 and was significantly greater than that in intact animals. The nucleo-cytoplasmic ratio of supraoptic hypothalamic neuron at 2 a.m. was lower than that in intact animals due to a decrease in specific nucleus volume. In comparison with the day period (2 p.m.), before 2 a.m. there was revealed a decrease of the neuron body area of supraoptic nuclei of hypothalamus due to possible decrease of the area of nucleus and nucleolus of cells. This was the reason for the increase in the nucleo-cytoplasmic ratio in the neurons under observation at night, which was 2.51 ± 0.023 units. Constant light regime did not cause inversion of the rhythm of morphofunctional activity of the neurons under study, the maximum values, as in intact animals, occurred in the daytime observation period.

Location of Subcortical Microbleeds and Recovery of Consciousness After Severe Traumatic Brain Injury

Background:In patients with severe traumatic brain injury (TBI), coma is associated with impaired subcortical arousal mechanisms. However, it is unknown which nuclei involved in arousal (“arousal nuclei”) are implicated in coma pathogenesis and are compatible with coma recovery.Methods:We mapped an atlas of arousal nuclei in the brainstem, thalamus, hypothalamus, and basal forebrain onto 3 Tesla susceptibility-weighted images (SWI) in twelve patients with acute severe TBI who presented in coma and recovered consciousness within six months. We assessed the spatial distribution and volume of SWI microbleeds and evaluated the association of microbleed volume with the duration of unresponsiveness and functional recovery at six months.Results:There was no single arousal nucleus affected by microbleeds in all patients. Rather, multiple combinations of microbleeds in brainstem, thalamic, and hypothalamic arousal nuclei were associated with coma and were compatible with recovery of consciousness. Microbleeds were frequently detected in the midbrain (100%), thalamus (83%) and pons (75%). Within the brainstem, the microbleed incidence was largest within the mesopontine tegmentum (e.g., pedunculotegmental nucleus, mesencephalic reticular formation) and ventral midbrain (e.g., substantia nigra, ventral tegmental area). Brainstem arousal nuclei were partially affected by microbleeds, with microbleed volume not exceeding 35% of brainstem nucleus volume on average. Compared to microbleed volume within non-arousal brainstem regions, the microbleed volume within arousal brainstem nuclei accounted for a larger proportion of variance in the duration of unresponsiveness and 6-month Glasgow Outcome Scale-Extended scores.Conclusions:These results suggest resilience of arousal mechanisms in the human brain after severe TBI.

Volumetric trajectories of hippocampal subfields and amygdala nuclei influenced by adolescent alcohol use and lifetime trauma

Alcohol use and exposure to psychological trauma frequently co-occur in adolescence and share many risk factors. Both exposures have deleterious effects on the brain during this sensitive developmental period, particularly on the hippocampus and amygdala. However, very little is known about the individual and interactive effects of trauma and alcohol exposure and their specific effects on functionally distinct substructures within the adolescent hippocampus and amygdala. Adolescents from a large longitudinal sample (N = 803, 2684 scans, 51% female, and 75% White/Caucasian) ranging in age from 12 to 21 years were interviewed about exposure to traumatic events at their baseline evaluation. Assessments for alcohol use and structural magnetic resonance imaging scans were completed at baseline and repeated annually to examine neurodevelopmental trajectories. Hippocampal and amygdala subregions were segmented using Freesurfer v6.0 tools, followed by volumetric analysis with generalized additive mixed models. Longitudinal statistical models examined the effects of cumulative lifetime trauma measured at baseline and alcohol use measured annually on trajectories of hippocampal and amygdala subregions, while controlling for covariates known to impact brain development. Greater alcohol use, quantified using the Cahalan scale and measured annually, was associated with smaller whole hippocampus (β = −12.0, pFDR = 0.009) and left hippocampus tail volumes (β = −1.2, pFDR = 0.048), and larger right CA3 head (β = 0.4, pFDR = 0.027) and left subiculum (β = 0.7, pFDR = 0.046) volumes of the hippocampus. In the amygdala, greater alcohol use was associated with larger right basal nucleus volume (β = 1.3, pFDR = 0.040). The effect of traumatic life events measured at baseline was associated with larger right CA3 head volume (β = 1.3, pFDR = 0.041) in the hippocampus. We observed an interaction between baseline trauma and within-person age change where younger adolescents with greater trauma exposure at baseline had smaller left hippocampal subfield volumes in the subiculum (β = 0.3, pFDR = 0.029) and molecular layer HP head (β = 0.3, pFDR = 0.041). The interaction also revealed that older adolescents with greater trauma exposure at baseline had larger right amygdala nucleus volume in the paralaminar nucleus (β = 0.1, pFDR = 0.045), yet smaller whole amygdala volume overall (β = −3.7, pFDR = 0.003). Lastly, we observed an interaction between alcohol use and baseline trauma such that adolescents who reported greater alcohol use with greater baseline trauma showed smaller right hippocampal subfield volumes in the CA1 head (β = −1.1, pFDR = 0.011) and hippocampal head (β = −2.6, pFDR = 0.025), yet larger whole hippocampus volume overall (β = 10.0, pFDR = 0.032). Cumulative lifetime trauma measured at baseline and alcohol use measured annually interact to affect the volume and trajectory of hippocampal and amygdala substructures (measured via structural MRI annually), regions that are essential for emotion regulation and memory. Our findings demonstrate the value of examining these substructures and support the hypothesis that the amygdala and hippocampus are not homogeneous brain regions.

Lenticular nucleus volume predicts performance in real-time strategy game - cross-sectional and training approach using voxel-based morphometry

It is unclear why some people learn faster than others. We performed two independent studies in which we investigated the neural basis of real-time strategy (RTS) gaming and neural predictors of RTS games skill-acquisition. In the first (cross-sectional) study we found that experts in the RTS game StarCraft II (SC2) had a larger lenticular nucleus volume than non-RTS players. We followed a cross validation procedure where we used the volume of regions identified in the first study to predict the quality of learning a new, complex skill (SC2) in a sample of individuals who were naïve to RTS games (second training study). Our findings provide new insights into how the volume of lenticular nucleus, which is associated with motor as well as cognitive functions, can be utilized to predict successful skill-learning, and be applied to a much broader context than just video games, e.g. contributing to optimizing cognitive training interventions.

The evolution of red blood cell shape in a continental radiation of fishes

The size and shape of Red Blood Cells (RBC) can provide key information on life history strategies in vertebrates. However, little is known about how RBC shape evolved in response to environmental factors and the role of phylogenetic relationship. Here, we analyzed RBC morphometrics in a continental radiation of fishes testing the hypothesis that phylogenetic relationship determines species occupation of morphospace. We collected blood samples of five specimens of 15 freshwater fish species from six orders and used basic stereological methods to measure cell and nucleus area, perimeter, and diameter, cell and nucleus volume, nucleus:cytoplasm ratio, and shape factor of 50 cells per specimen. Then, we conducted a phylogenetic Principal Components Analysis using a dated phylogeny and built a phylomorphospace. To test if the phylogenetic relationship predicted the phenotypic similarity of species, we calculated multivariate phylogenetic signal. We also estimated the evolution rate of RBC shape for each node and tip using ridge regression. Finally, we tested if the position in the water column influenced RBC shape using a phylogenetic GLS. RBC shape seems to have evolved in a non-stationary way because the distribution pattern of species in the phylomorphospace is independent of the phylogeny. Accordingly, the rate of evolution for shape was highly heterogeneous, with an increase in the genus Pygocentrus. Water column position does not influence RBC shape. In conclusion, RBC shape seem to have evolved in response to multiple selective pressures independent of life history characters.

THE RESPONSE OF PLACENTAL DECIDUAL CELLS TO TREATMENT OF CHLAMYDIOSIS IN PREGNANT WOMEN

Цель исследования: оценка влияния антибиотиков на структуру децидуальных клеток плаценты при лечении хламидиоза во время беременности. Методика. Гистологическими методами изучали децидуальные клетки различных зон плаценты от рожениц с неосложненной беременностью и с хламидиозом, пролеченным во время беременности. Препараты готовили стандартным гистологическим методами с окраской гематоксилин-эозином. Гисто-стереометрически определяли большой и малый диаметры децидуальных клеток и ядер, количество децидуальных клеток на мм2 площади базальной пластинки и септ. Вычисляли ядерно-цитоплазматическое отношение, объемы децидуальных клеток, их цитоплазмы и ядер. Охарактеризованы клеточные популяции стромальных децидуальных клеток базальной пластинки и септ. Составлены вариационные графики объема ядер децидуальных клеток базальной пластинки и септ. Результаты. Установлено, что антибактериальная терапия действует преимущественно на клетки центральной зоны плаценты, изменяя ядерно-клеточный аппарат децидуальных клеток, при этом клеточно-пролиферативный статус клеток снижается к периферии плаценты, где компенсаторно-приспособительные механизмы децидуальных клеток работают слабо. Это сопровождается ослаблением необходимых иммунных реакций в плаценте. Появление дополнительных мод в графиках объема ядер может свидетельствовать о высокой митотической активности и набухании ядер, что, вероятно, связано с цитотоксическим действием антибактериальных препаратов. Заключение. Использованная схема антибактериальной терапии хламидиоза у беременных оказывает незначительный положительный эффект. Результаты работы могут быть использованы для разработки новых схем лечения хламидиоза во время беременности, с использованием антибактериальных препаратов с более щадящим действием на ядерно-клеточный аппарат децидуальной ткани плаценты. Aim. To evaluate the effect of antibiotics on placental decidual cells in the treatment of chlamydiosis during pregnancy. Methods. The study was performed on 6,000 decidual cells in different zones of placenta from mothers with uncomplicated pregnancy and chlamydiosis treated during pregnancy. The cells were stained with hematoxylin-eosin according to standard histological techniques. Method. The major and minor diameters of decidual cells and nuclei and the number of decidual cells per mm2 of basal lamina and septa were determined using histostereometry. Based on the obtained values the nucleus-cytoplasm ratio and volumes of decidual cells, their cytoplasm and nuclei were calculated. Populations of stromal decidual cells of the basal lamina and septa were characterized. Variation curves of nucleus volume were constructed for decidual cells of the basal lamina and septa. Results. The antibiotic therapy affected primarily cells of the placenta central area. In this process, the cell proliferative status decreased toward the periphery of placenta where compensatory-adaptive mechanisms of decidual cells are weak. This was associated with impairment of essential immune responses in the placenta. The emergence of additional peaks in the variation curves of nucleus volume may indicate high mitotic activity and functional swelling of nuclei, probably due to cytotoxic effects of antibacterial drugs. Conclusion. The used regimen of antibiotic therapy for chlamydiosis in pregnant women exerted a minor beneficial effect. Results of this study can be used to develop new regimens for treatment of chlamydiosis during pregnancy with antibacterial drugs with a weaker effect on the nucleus apparatus of cells in the placental decidual tissue.