[Vestibular effects on posture instability evoked by moving visual environment and footing].

Subjects held the vertical posture standing up on hard footing, having small degree of the freedom in the frontal plane. The stability of the vertical posture has been assessed by the standard deviations (sigma) from average amplitudes of the fluctuations of the subject's head (in frontal and sagittal planes) from conditional zero. Sinusoidal rotations of optokinetic cylinder, sinusoidal rotations of the footing, and combinations of these rotations, under phase shifts between the optokinetic cylinder and the footing, caused increase of sigma. The amplitude and velocity signal of the head deviations was transformed into low galvanic current applied to the mastoids and used as the artifical vestibular biofeedback. It was possible to reduce the value of the sigma for lateral tilts (raised in comparison with their values during stance in the dark as a result of destabilizing influence), varying coefficients of the biofeedback. At the same time, appropriate fluctuations in sagittal plane were not systematic.

[Phenomenon of rapid increase in loudness during residual masking of a tone with a tone]. / Iavlenie bystrogo narastanii gromkosti pri ostatochnoi maskirovke tona tonom.

The loudness recruitment effect mainly depended on masker and test-tone frequencies and to some extent on perception thresholds. The data obtained suggest connections among such properties of the auditory system as frequency selectivity, adaptation and loudness recruitment.

[Frequency characteristics of the masking effect: relationship between the characteristic variation factor and the frequency of the tone being masked]. / Chastotnye kharakteristiki effekta maskirovki: zavisimost' koeffitsienta neravnomernosti kharakteristik ot chastoty maskiruemogo tona.

The irregularity coefficient of the frequency characteristics of masking effect is a function of the frequency of masking tone with constant intensity (10 dB SL). The coefficient is growing by 9--12 dB per octave of the masking tone reaching 60 dB at the frequency 10 kHz. Similar dependence was found by measuring the frequency threshold curves of the cochlear nerve fibers. These values of the coefficient could not be obtained with the aid of classical model of the cochlea.

[Functional model of peripheral spectral auditory analysis (linear variant)]. / Issledovanie funktsional'noi modeli perifericheskogo spektral'nogo slukhovogo analiza (lineinyi variant).

Peripheral auditory system model consists of several parts: the first one being representative of the middle ear and basal part of the cochlea whereas the last one involves the first neuron level of the auditory nerve. Experimental data from basilar membrane motion and auditive nerve fiber activity for sinusoidal and click stimuli were used to define the transfer function of each part. A digital stimulation of this model and an analog construction were investigated and are discussed here. The model reproduces, with a good approximation the harmonic and transient behavior of the peripheral auditory system and enables to study the transmission of acoustical information towards the higher--level centers.