Zhurnal Vysshei Nervnoi Deyatelnosti Imeni I.P. Pavlova

Periodic hypoxia includes periods of low oxygen content, interspersed with periods of reoxygenation. Periodic hypoxia is usually associated with pathological conditions and is considered as a negative stimulus leading to disorders of cognitive functions, the cardiovascular system, respiration and metabolism. It is the most important pathophysiological element of sleep apnea syndrome, which is accompanied by the development of inflammation and oxidative stress. On the other hand, periodic hypoxia, unrelated to sleep apnea, has a positive or negative effect on the body, depending on the intensity, duration and number and frequency of hypoxic exposures. In medicine, periodic hypoxia is used to improve health and enhance performance and is a non-pharmacological treatment for a number of diseases. The goal of the present review is to summarize clinical and experimental data on the effect of periodic hypoxemic hypoxia on the adult body. Special attention is paid to the effect of periodic hypoxia on cognitive functions. The review discusses the molecular mechanisms by which periodic hypoxia can trigger a cascade of intracellular reactions leading to either beneficial or pathological effects.

In this study, wavelet analysis of EEG was performed during cyclic motion of auditory stimuli. EEG was recorded during passive listening to stimuli designed to model binaural beats by means of cyclic changes in interaural time differences (ΔT). We analyzed the changes in event-related spectral perturbation (ERSP) and phase coherence (ITC) of oscillatory activity underlying the responses to motion onset (motion-onset response, MOR) and motion offset (omitted-stimulus response, OSR). In the response to motion onset, the ERSP and ITC of theta oscillations were highest when the stimulus was near the head midline, and decreased when the stimulus was 45 or 90 deg away from the midline. Right-hemispheric ERSP and ITC were most sensitive to the motion onset position. Responses to motion offset were similar for all spatial positions of the stimulus, and were mainly generated by the phase synchronization (ITC) of theta oscillations that continued after the motion offset.

Heterogeneity of mental aging is largely determined by the interaction of environmental and genetic factors. Previously, during analysis of age-related changes in the global power of the background EEG, only in elderly subjects we identified differences that were moderated by the STin2VNTR polymorphism of the serotonin transporter gene and training due to the intellectual load of the professional environment (comparison of scientists, SA, and people not associated with professional scientific activity, NSA). For slow rhythms, the greatest differences were observed between homozygous genotypes, with the lowest power values in elderly NSA in the 10/10 group, and in SA – 12/12. The aim of this study was to determine the spatial pattern of current source density (CSD) underlying the identified power decreases in the 10/10 NSA and 12/12 SA genotypes. The study involved elderly subjects (55–80 years; 66 SA and 76 NSA). Voxel-by-voxel analysis using eLORETA showed no local features of the CSD decrease for the 10/10 NSA genotype compared to 12/12 NSA. Thus, the previously noted decrease in the power of slow rhythms in the 10/10 NSA group may be due to a unidirectional diffuse decrease in different areas of the cerebral cortex. In contrast, in 12/12 SA group compared to 10/10 SA, spatial patterns of CSD decrease were revealed in the delta rhythm frequencies mainly in the precuneus, inferior and superior parietal lobule of the left hemisphere, in the alpha2 and alpha3 rhythm frequencies – in the precuneus and superior parietal lobule of the right hemisphere. The data obtained may indicate an adaptive reorganization of neural networks associated with cognitive training in elderly scientists carrying the 12/12 genotype.

Влияние нейровоспаления на реконсолидацию памяти о страхе слабо изучено, исследовались только острые, но не отдаленные эффекты интоксикации. В настоящей работе мы изучали влияние отдаленного провоспалительного липополисахаридного (ЛПС) стресса на реконсолидацию и угашение памяти о страхе у взрослых самцов крыс Вистар. На 3-й и 5-й постнатальный день (ПНД), во время критического периода постнатального онтогенеза, крысам подкожно вводили ЛПС (50 мкг/кг, группа LPS) или физиологический раствор (группа SAL). На 120 ПНД у крыс вырабатывали условнорефлекторный страх с помощью трех сочетаний звукового тона и удара током по лапам. Через 24 час после обучения у одной группы крыс проводили реактивацию памяти, помещая их в ту же обстановку и давая одно применение тона (Re+), другая группа крыс оставалась в домашней клетке (Re‒). Через 24 час в тесте 1 на сохранность памяти во всех группах определяли время замирания. После теста 1 в течение двух дней проводили угашение реакции, давая по 10 тонов каждый день, после чего следовал тест 2. В тесте 1 у крыс, получавших SAL, в группе Re+ по сравнению с группой Re‒ была нарушена память об обстановке, но не память о сигнале. После раннего LPS стресса уровень замирания на обстановку в группах Re+ и Re‒ не различался, что свидетельствовало о том, что раннее нейровоспаление ослабляло обновление контекстуальной памяти о страхе. Различия в уровне замирания в группах Re+ и Re‒ сохранялись во время угашения и в тесте 2. В группе LPS угашение реакции было более медленное, чем в группе SAL. Таким образом, отдаленное нейровоспаление нарушает процесс обновления и угашения памяти о страхе.