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Vol 38, No 1 (2024)
ОБЗОР
Рroblems of diagnostics of dysfunctions of the olfactory analyzer of laboratory animals on the basis of behavioral and electrophysiological methods of research
Abstract
Olfactory impairment (decreased acuity, impaired adequate identification of odorants) reduces the quality of life of patients and can be a symptom of a wide range of pathologies of the organism, in particular neurodegenerative processes in the brain. Quantitative measurement of olfactory acuity is necessary for diagnostics of olfactory dysfunctions, monitoring the dynamics of olfaction after pharmacological or surgical treatment. The searching for optimal methods of analyzing olfactory thresholds on animal models of human diseases accompanied by anosmia and comparing them with those in humans seems to be especially urgent problem at the moment. This is necessary for the selection of a valid animal model for the evaluation of new drugs and development the therapy for a wide range of pathologies.
The review analyzes publications devoted to the study of diseases accompanied by anosmia or hyposmia, their zootropic models, and methods of olfactory function assessment. Models for COVID19, Alzheimer’s disease, Parkinson’s disease, diabetes types (1 and 2 type), Kalman syndrome, and Bardet-Biedl syndrome, for which olfactory dysfunction and/or defects of olfactory system are present, were analyzed. The review notes the paucity of data on the measurement of olfactory thresholds in model animals.
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ЗРИТЕЛЬНАЯ СИСТЕМА
Changes in the visual areas of the cerebral cortex in children with left-sided anisometropic amblyopia according to structural MRI and resting-state fMRI
Abstract
Thanks to the development of structural and functional magnetic resonance imaging (MRI) methods, in recent decades there has been a lot of research aimed at elucidating brain abnormalities caused by amblyopia. In the cases of this prevalent visual disorder, the anomalies causing decreased visual acuity and other visual disabilities cannot be determined by standard ophthalmologic examination. Since there are several types of this disorder that are fundamentally different in etiology, it is natural to suggest the presence of different types of corresponding brain abnormalities. In this regard, before obtaining a general picture of the pathogenesis of amblyopia, studies conducted on groups of specially selected similar patients are very important. This paper presents the results of a study of school-age children with left-sided anisometropic amblyopia. In the patients investigated, MRI data revealed interhemispheric differences in the thickness of the lateral occipital cortex, and resting-state fMRI revealed interhemispheric differences in the local coherence of the hemodynamic signal within 17 Brodmann area and in the functional connectivity between 17 and 18+19 Brodmann areas. The data obtained contribute to the creation of a general MRI database on the pathophysiology of amblyopia, help clarify some controversial issues and indicate the advisability of using resting-state fMRI in ophthalmology.
30-44
In search of the molecular mechanisms of adaptation memory in rods: basic activity of phosphodiesterase
Abstract
Retinal rods, the photoreceptors responsible for twilight vision, are capable of adapting to a wide range of light levels. The molecular mechanisms of light adaptation have been well studied, but an interesting question is what changes occur in the phototransduction cascade after the adaptive light stimuli are eliminated. Previously, we showed the phenomenon of adaptation memory in amphibian rods: after background illumination photoreceptor sensitivity to light remained reduced for several minutes, while the dark current recovered within 20—30 s. This suggests the existence of additional, as yet unknown, regulatory mechanisms of the phototransduction cascade that act after the adaptive effect of light. In search of specific mechanisms that could explain the effect of adaptation memory, we performed electrophysiological experiments on isolated frog rods to evaluate the basal activity of the effector enzyme of the phototransduction cascade, the phosphodiesterase type 6, in the dark and after saturating background illumination. It was found that the post-adaptation state of rods was characterized by increased basal phosphodiesterase activity, which gradually decreased to the dark level within tens of seconds after turning off the adaptive illumination. These results also suggest that the components of the phototransduction cascade may undergo some unstudied changes after light adaptation.
45-51
Non-invasive recording of electroretinogram from both compound eyes in the cockroach Periplaneta americana L. in response to light stimuli
Abstract
The paper presents an original method of non-invasive registration of electroretinogram from both compound eyes of an insect. The method demonstrated high reliability and repeatability of the results. Using this method, it was shown that the magnitude of the light responses obtained from mutant cockroaches devoid of screening pigment, pearl, was about 4 times greater than those of wild-type insects. The time to peak of the response decreased with increasing light intensity, both for short-wavelength and long-wavelength stimuli. The pearl cockroaches exhibited a faster time to peak response than wild-type cockroaches; the results of covariance analysis indicate that these differences cannot be fully explained by an increase in the number of photons reaching the photoreceptor membranes and suggest additional differences in the compound eye physiology of mutant and wild-type insects. The positive voltage wave after the end of light stimulation depends on light intensity and reflects hyperpolarization of receptor cells. The photovoltaic effect, which distorts the amplitude and the shape of the response can be eliminated by using a gold wire as a recording electrode.
52-65
Individual and typological features of motor memory in problems of control of ergacy systems in the absence of visual feedback
Abstract
The purpose of the study was to determine the impact of the presence of visual feedback on the quality of user experience with a number of human-computer interfaces, as well as the process of mastering the interfaces. As a result of the work, the features of the generation of control commands by operators of ergatic systems using an oculographic interface, interfaces for controlling hand movements and head movements were assessed. In the absence of visual feedback, users relied on motor memory formed during the learning process, and in the case of head control, on data from the vestibular analyzer.
The presence of visual feedback was found to be important for accurate command generation in all cases. However, when controlling the head and eyes, the presence of visual feedback led to a greater deviation from the ideal trajectory and an increase in the distance that the cursor traveled before reaching the goal. Localization of the target position did not have a significant effect on the performance of the operator interface, regardless of the presence of visual feedback.
Analysis of typical reactions in all experiments made it possible to identify three types of control, differing for eye and head movements, but not for hand movements in the ergatic system mode. Types 1 and 2 exhibited more errors compared to type 3, and the number of errors varied between them, especially for hand control.
The results obtained can be used in the development of promising interfaces for ergatic systems, including the determination of the necessary visual feedback components for this class of technical devices.
66-78
СЛУХОВАЯ СИСТЕМА
Discrimination of rippled spectra with various ripple widths in listeners with normal and impaired hearing
Abstract
In listeners aged 26 to 82 years with various degrees of hearing loss (from normal to moderate), the frequency resolving power (FRP) was assessed as the resolved ripple density resolution in rippled-spectrum signals at various ripple widths. In normal-hearing listeners, FRP increased with narrowing the ripple width. In impaired-hearing listeners, the effect of narrowing the ripple width was minor. The difference between the normal- and impaired-hearing listeners could not be explained by the excitation pattern model of the rippled spectrum resolution. The temporal analysis model did explain this difference on an assumption that in normal hearing listeners, enhancing the autocorrelation of the input signal resulted in prolongation of the delay at which the autocorrelation could be detected by the auditory system, whereas in impaired-hearing listeners this effect was reduced or absent.
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