[Speech rhythm disorders due to synchronization induced in coupled inhibitory neurons].

Leaked-integrate-and-fire coupled oscillators (LIFs) were used as a model of electrophysiological activity. The activity of these oscillators determines the speech rhythm, which is governed by the square-law map with inhibition as a controlling parameter. Regular rhythms of convulsive repetitions at early stuttering are changed, however, by a mixture of repetitions and neurotic pauses. This mixture is a "stumbling block" for clinicians. Due to delays, only inhibitory LIFs are capable to create the synchronic activity in-phase or in-anti-phase at medial or at low coupling. This activity has the form of slow oscillations damping to the background level. Splashes of the activity above or below the level lead to neurotic disorders or to convulsive repetitions. Really, increased due to GABA the coupling leads to a reduction of stuttering.

[The mechanism of verbal memory and scenario of the development of speech V-rhythms].

It was shown that the Feigenbaum scenario for the transition of bifurcation of period doubling to chaos, which explains the singularities of V-rhythm disorders in the neighborhood of the critical point, is a good model of the development of phonetics in children speech. It was also shown that the singularities of the dynamics of V-rhythms in the bifurcation lacuna in the zone of chaos intrinsic to the Pomeau-Manneville scenario for route of bifurcations of period 3 to chaos are capable, basically, to describe some features of both remembrance at the extraction from memory during speech and remembering in memory during perception of speech.

[Lagrange formulation of the self-organization problem of a neuronal ensemble during computation of nonlinear dissipation of energy]. / Lagranzheva formulirovka problemy samoorganizatsii neironnogo ansamblia pri uchete nelineinoi dissipatsii énergii.

The Lagrange formulation for the problem of excitation of the Bresslow neural network is given to construct an arbitrary law for energy dissipation of the ensemble. The Amari assumption about neuron conductivity as a function of membrane potential allows one to admit the logistic dissipation law. It was shown that, from the viewpoint of statistics, this law is valid at coherent excitation conditions. The property of factorizing for the functioning of this ensemble was obtained.

[Biophysical basis for principles of universality of speech perception]. / Biofizicheskie osnovy printsipa universal'nosti vospriiatiia rechi.

There is increasing evidence that the synergistic interaction of the objectively accepted low-frequency rhythm and the subjectively accepted high-frequency sound is a source of speech "sense". The lack of one of these components or of their synergistic interaction results in the loss of "sense" of the acoustic signal being perceived. As for the universality of perception of the sound component of speech, there is a model of sound perception, which ensures this universality. This model describes the dynamics of audition using the synchronization model of oscillations in the Ruell-Takens scenario of transition to chaos. The oscillations are described by Hopf bifurcations known to be structurally stable, which just provides the universality of sound perception. However, up till now, nothing was known about the mechanism of rhythm. It was shown in our study that the mechanism of rhythm is described by the Feigenbaum scenario of transition to chaos. Upon transition from oscillations to chaos, this scenario incorporates a critical point near which the dynamics of the system is described in an universal way.

[Self-organization nature of forming speech rhythm (the voice source model]. / Samoorganizatsionnye zakonomernosti formirovaniia rechevogo ritma (model golosovogo istochnika).

The rhythmic structure of the temporal organization for acoustical speech signal is outlined on the base of self-organization. Suggested physiologically plausible nonlinear dynamics for process in discrete time has agreement with the experiment and explains the nature of the speech rhythm. Empirical speech rhythm has a good agreement with the model prediction.

[The neurophysiological aspects of the recurrent functioning of the "hidden" variables of the speech apparatus]. / Neirofiziologicheskie aspekty rekurrentnogo funktsionirovaniia "skrytykh" peremennykh rechevogo apparata.

The "hidden" recurrent structure is established of temporal organization of acoustic speech signal. Such "hidden" recurrence can be revealed only due to experimentally established existence of two qualitatively different modes in the temporal organization of stutterers' speech. A theoretical model of speech generation is developed with a logistical property of "hidden" parameters in order to explain this phenomenon. This model is stated in terms of chaotic dynamics and is based on the neurophysiological striopallidal mechanisms which are realized under conditions of polysensory afferent impulsation. The effects of speech memory and actualization of its traces are explained on the basis of our earlier concept of perception of the rhythmical speech sequence. This concept allowed us to discuss the experimentally observed phenomenon of inhibitory modulation under conditions of both ipsi- and contralateral global negative feedback.