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M S Livshits

Publications and source records attributed to M S Livshits.

13 recordsLinked to original sources
PubMedDate not supplied

[Terrain observation by the horseshoe bat Doppler echolocator].

Results of further studies of physical bases of surroundings observations with Rhinophidae echolocator are presented. The observation is carried out due to the presence of pointed down irradiation diagram petal of its probing impulse. The frequency shift and devation of the signal, reflected from elementary surroundings region, induced by Dopler effect, are calculated. It is shown that the presence in the frequency threshold curve of Rhinophidae auditory system of a narrow-tuned filter in the location frequency region and control of the frequency of eminated impulse during flight provide for a response of the auditory system to the signal reflected from each point of surroundings. The resolution thus obtained is evaluated. A technique is suggested for experimental test of the work of the system for surroundings observation.

Animals↗
PubMedDate not supplied

[Letter: Work of the impulse section of the horseshoe bat echolocator].

Peculiarities of location impulse of Rhinolophidae bring about a distinctive combination of dopler and impulse parts working almost independently, in its locator. In particular the range of the effect of impulse locator connected with the presence of LFM splash in the end of location cry is determined by the value of the period of its repetition. The existence of a long monofrequent part of locaion impulse providing the work of acholocator dopler part due to its narrow bands presents only a comparatively small obstacle to the impulse locator.

Animals↗
PubMedDate not supplied

[Correlation model of object recognition by echolocating animals].

The model proposed in an attempt to find out physical bases of object perception during echolocation. It is shown that echolocational perception can be provided with correlational treatment of corresponding signals. The character of objects is determined by the comparison by echo probing accepted in the given cycle with typical distortions remembered in the course of individual experience of the animal. The distortions take place during the reflection of the probing impulse from these or those objects. "Binding" of the objects according to distance may be carried out by using the choice of typical distortions for corresponding correction of the copy of probing impulse, serving as a bearing signal of distance correlometer. The response of correlometer to the echo from correctly perceived target increases. The block-scheme of such correlation perception during echolocation is given. Performance of some experiments allowing to check and refine the model considered.

Animals↗
PubMedDate not supplied

[Phenomenological model of the system for exact determination of target direction by the bat echolator].

A functional scheme of correlation treatment of an echosignal during the determination of a direction to the target by rats echolator is considered. The scheme proceeds from a suggestion that for an exact measurement of angle coordinates of the target the rat applies a location method of unisignal zones resulting from the pulsation of direction diagram when LFM impulse is emitted. Some considerations in favour of the suggested phenomenological model are presented. An experimental set-up which permits to test and specify the model is proposed.

Animals↗
PubMedDate not supplied

[Loudness measurement and automatic control in the acoustic analyzer].

A block diagram of a hearing system is presented in which external hair cells are used to measure the loudness level and to adjust automatically internal hair cells. This system may assure an optimal function of the basic acoustic systems responsible for sound analysis. The data presented form a theoretical foundation for an adequate physiological interpretation of the recruitment phenomenon recorded in certain forms of neurosensory hypoacusis.

Hair Cells, Auditory↗
PubMedDate not supplied

[Modeling of auditory mechanisms of pitch perception].

A hypothesis of two subordinately interconnected pitch perception systems is put forward and described. The leading system is responsible for the analysis of periodical sequences of spikes along audioneurons whose generation moments are synchronized by the acting sound oscillations. This system allows measuring of any periodical sound--simple or complex--including the residual sound. However, the system of periodicity analysis does not ensure the experimentally determined precision of pitch change perception. It is shown that the signal distribution along the basilar membrane enables the activation of the second system which analyses the spatial--temporal image by means of a great number of well innervated internal receptor cells. This system functioning is characterized by small values of differential threshold pitches, since as a discriminatory characteristic a curt decline of the basilar membrane oscillation envelope is used which is formed after a prolonged sinusoidal sound.

Basilar Membrane↗
PubMedDate not supplied

[Inner ear cochlear processes].

The processes accompanying the propagation across the basilar membrane (BM) of waves from a wide-band sound signal have been analyzed by physical methods. Particular emphasis in placed on the fact that BM is a low frequency filter. The characteristics of wave envelope from each of the sinusoidal components of the signal are given. The use of a simple mechanical model makes it possible to explain an initial increase in these envelopes. The steep slope of the envelope in its terminal part is explained in terms of the lighthill hydrodynamic model of cochlea. This provides a theoretical basis for adequate description of the periphery of the ear analyzer, with allowance for the active role of external auditory hair cells (EHC). Further research is needed to solve the problem completely. This is dictated by the complexity of the oscillatory system (BM in the region of the critical layer of cochlea plus EHC) and by its interaction with the autoregulation system in the air analyzer, which is described elsewhere.

Basilar Membrane↗
PubMedDate not supplied

[Automatic regulation in the auditory analyzer and the phenomenon of accelerated growth of loudness].

Physical analysis of the ear periphery structure and the data on loudness perception have been used to develop a model of loudness measurement and self-control in the hearing analyzer. The experimental results obtained recently by different researchers are shown to confirm that the basic ideas of this model are reasonable, and the model is of considerable heuristic importance. The author provides treatment of the main hearing "paradox", that is the existence of a wide dynamic range of loudness perception for a narrow range of afferent pulsation in auricular nerve fibers. A simple explanation is found for the so-called adaptation phenomenon. The explanation of the phenomenon of loudness increase acceleration typical for many forms of neurosensory hypoacousis opens up new perspectives in the diagnostics and treatment of these diseases.

Adaptation, Physiological↗
PubMedDate not supplied

[Model of the system for stabilizing the frequency of the echosignal of the Rhinolophus locator].

Physical analysis of anatomic, physiological and behavioural data pertaining to the work of Rhinolophidae echolocator is carried out, results of spectral analysis of its probing impulse are analysed. On this basis the working mechanism of sound emitting apparatus is proposed. A phenomenological model of the frequency stabilization system of the signal reflected from a located object is constructed. This stabilization is carried out by the compensation of Doppler shift of the echo frequency by a change of the generated impulse frequency. Due to the application of a differential method the model provides for potential accuracy of tuning, and its work does not depend on the value of a reflected signal and its sufficiently small changes which is in agreement with the experiments.

Animals↗
PubMedDate not supplied

[Calculation of potential accuracy in measuring the angular coordinates of targets by the echolocator of bats using the equal-signal zone method].

Potential accuracy in measuring the course to a target is calculated. This accuracy is physically achievable it the hypothesis that an accurate measurement of angular coordinates of the target of bat's echolocator is realized by the method similar to that of equally signaling zone in radiolocation is true. Possible application of such a method is based on the "pulsation" of direction diagram in the course of radiation of the probing impulse. In this case crossing of partial diagrams of radiation corresponding to high- and low-frequancy regions of the impulse form the equally signaling zine. If the target is in this direction the amplitudes of autocorrelation functions formed by corresponding regions of reflected and probing impulses will be equal. The minimal error of the method is limited by the optimum duration of each of the compared correlation functions, which forms the basis for derivation of the formula evaluating this error. Numerical calculation of the accuracy of measurements of the angle achievable for the echolocator of Myotis blythi is performed by this formula proceeding from average experimental values of the echolocator characteristics. The model under consideration is shown to agree with a number of experimental data.

Animals↗