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Gamma band oscillations (25 - 70 Hz) play an important role in processing of information by neocortical neurons. In simple cells of the cat's visual cortex, it was previously shown that strength of gamma oscillations is modulated by the membrane potential oscillations at the temporal frequency of the stimulus. More recently, theoretical studies using a conductance-based neuronal model have shown that this coupling significantly improves visual stimulus encoding. Due to the availability of a broad range of genetic tools, mice had recently become an important experimental subject for research in various fields of neuroscience, including visual physiology. It has been suggested that gamma oscillations in the mouse visual cortex play a minor role in visual processing due to the lack of specialized neurons that take part in generating gamma oscillations. Here we show, using patch clamp recording from simple cells in the visual cortex of anesthetized mice, that the strength of gamma oscillations is modulated by the phase of stimulus-induced oscillations during visual stimulation with moving gratings. In addition, using patch clamp recording from mouse visual cortex neurons in slices, we demonstrated benefits of gamma activity modulation for encoding of slow sinusoidal signals into sequences of action potentials. Thus, the phenomenon of amplitude modulation of gamma oscillations by temporal frequency of stimulus, originally described in the visual system of cats, may represent a universal mechanism that improves encoding of visual information which is present even in animals with a relatively poorly developed visual system, such as mice.

Spontaneous activity is known to be a characteristic feature of the vast majority of the neocortical principal cells including neurons of the primary sensory areas. The question of how spontaneous activity interacts with perception and encoding of sensory information remains open. In the present study, pyramidal neurons of the mouse primary visual cortex were recorded extracellularly under urethane anesthesia and simultaneous single-channel EEG recording was performed. To evaluate orientation and direction selectivity of the recorded neurons, mice were presented with visual stimuli consisting of moving sinusoidal gratings of different orientations displayed on a monitor. We noted quite regular bursts of generalized brain activity that were manifested in the recorded neuron as bundles of action potentials accompanied with a distinctive EEG pattern. Clearly, whenever such spontaneous activity shows up during visual stimulation, it is considered as noise, which significantly compromises the characteristics of the neuron’s measured visual response. To eliminate this effect, we developed a machine learning-based algorithm that enables to identify EEG predictors of generalized spontaneous activity and then to exclude spontaneous (i.e. not evoked by visual stimulation) action potentials from the recording. Our algorithm was shown to reliably detect action potentials that have been caused by generalized brain activity. Removal of action potentials of this origin from extracellular recordings obtained during visual stimulation allows for a more adequate estimation of parameters of neuronal receptive fields, in particular their orientation selectivity.

The study aimed to evaluate the effectiveness of previously developed methods of adaptive neurostimulation in correcting stress-induced states in specialists who demonstrate signs of post-traumatic stress disorder (PTSD) and professional burnout syndrome (PBS). Materials and methods. Each of the 17 stressed subjects participated in three examinations, alternated in random order. In the control experiment (control), simple listening to classical music was used. In two other examinations, musical or light-musical stimulation was used, automatically modulated by feedback signals from the rhythmic components of the subject's electroencephalogram (EEG). In the first case (musical feedback), the subjects were presented with music-like stimuli formed on the basis of the subject's alpha EEG oscillator. In the second case (double feedback), such musical stimulation was supplemented by rhythmic light stimuli generated by online transformations of the native EEG of the subject. Results. Comparison of the effects of both experimental conditions with the control one allowed us to establish that only in the presence of feedback from the EEG, there is a significant increase in the power of alpha EEG rhythm, accompanied by positive emotional reactions, a decrease in the level of disadaptation and stress, as well as a significant increase in the assessments of health and mood of the subjects. The most pronounced psychophysiological effects were recorded under light-music stimulation with double feedback from the EEG. Conclusion. The obtained results make it possible to suggest the described methods of adaptive neurostimulation as a means of psychotherapeutic correction of PTSD and PBS, especially during the COVID-19 pandemic.

The three-dimensional structure of tumor tissue and particularly cell-cell and cell-extracellular matrix adhesion is an important factor that can determine the phenotype of tumor cells. In this work, we have investigated the abundance profile of actin-binding adhesion proteins in human ovarian adenocarcinoma cell lines SKOV-3 and SKOV-3.ip. We have investigated levels of total and superficially localized adherens junctions proteins E- and N-cadherin, gap junction protein сonnexin-43 and cell-extracellular matrix contacting integrin beta-1. Our results indicate a complete absence of epithelial marker E-cadherin, a low level of mesenchymal N-cadherin and high levels of connexin-43 and integrin beta-1. Modest superficial localization of the represented proteins was observed, indicating their mislocalization. SKOV-3 cell line was characterized by higher levels of the total content of studied cell-cell contacts proteins and a lower level of superficially localized integrin beta-1, which is both considered to be associated with lower tumor aggressiveness. The revealed differences in the profile of adhesion proteins are in line with the accepted view on SKOV-3.ip cell line having a more aggressive phenotype than that of SKOV-3. The revealed features of the total abundance of the adhesion proteins and their superficially localized pool made it possible to supplement the information on the nature of phenotypic differences between the studied cell lines.