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V N Dumenko

Publications and source records attributed to V N Dumenko.

At least 19 recordsLinked to original sources
PubMed2006

Electrographic correlates of adequate and erroneous responses evoked by conditioned signals of different functional signs during operant learning in dogs.

Power spectra over the frequency range 1-225 Hz in short-term (less than 1 sec) EEG reactions arising in different areas of the cerebral cortex in response to presentation of differential signals were investigated in dogs during operant feeding behavior in conditions of both adequate and erroneous responses. The energy levels of these reactions decreased several-fold as compared with responses to positive signals, mainly because of frequencies in the high-frequency range (90-225 Hz), where power was greater than not only the traditional range of 1-30 Hz, but also the gamma range of 30-80 Hz. The frequency composition of EEG reactions in adequate responses was determined by a series of discrete frequency subgroups belonging predominantly to the high-frequency band. In erroneous reactions, the discrete structure of the corresponding EEG reactions was lost.

Animals↗
PubMed2006

Regional characteristics of electrical responses (in the band 1-225 Hz) in the cerebral cortex to conditioned stimuli in operant conditioning.

Power spectra of short-term (less than 1 sec) electrical responses to conditioned stimuli were studied over the frequency range 1-225 Hz in dogs during food-related operant conditioning. These spectra demonstrated regional characteristics in terms of energy levels and frequency composition. Responses were more marked in the visual and parietal areas of the left hemisphere. Power in responses to a differential stimulus were significantly lower than with responses to positive stimuli, mainly because of the high-frequency range (80-225 Hz); energy levels in these two situations were similar during prestimulus intervals. The frequency composition of responses was defined by a series of discrete frequencies in the gamma (30-80 Hz) and high-frequency ranges.

Analysis of Variance↗
PubMed2005

Electrographic correlates of "internal states" evoked by positive conditioned stimuli during operant training in dogs.

Experiments were performed to address the energy characteristics (power spectra) of short-term (less than 1 sec) EEG reactions arising in different areas of the neocortex in response to positive conditioned stimuli presented in conditions of selective attention. These EEG reactions directly preceded the motor reactions, which consisted of a strong blow with the paw on a feeder pedal to obtain reinforcement. The energy levels of EEG reactions were 1.5-3 times greater than pre-stimulus levels. The frequency structures of the corresponding EEG reactions were divided into discrete frequency subgroups, including the traditional (1-30 Hz) and the gamma ranges (30-80 Hz) as well as higher-frequency components (80-200 Hz). In some cases, the greater proportionate increases in power occurred in the high-frequency band.

Animals↗
PubMed2003

Studies of selective attention in dogs using the coherence-phase characteristics of cortical potentials over a wide range of frequencies, 1-220 Hz.

The state of selective attention formed during operant food-related behavior was studied using the coherence-phase characteristics between potentials in several areas of the neocortex at frequencies of 1-220 Hz. Functional groups were identified among the areas compared, which appear to have priority for this state. The temporal relationships between potentials in these groups were established from values for coherence functions at a particular optimum level (0.7) mainly in the band 1-15 Hz and the high-frequency range 40-200 Hz. The phenomenon of synchronicity appeared at phase shifts close to zero, while at significant phase shifts the phenomenon of non-synchronous time relationships with defined spatial directions was seen in the high-frequency range.

Animals↗
PubMed1997

Study of the EEG phenomenon of high-frequency bursts in the neocortical electrical activity of dogs in the process of alimentary instrumental learning.

We studied the electroencephalographic (EEG) phenomenon of high-frequency (HF) bursts (within the limits of 60-170 cycle, 70-80 microV) in the electrical activity (EA) of the brain (1-200 Hz) of dogs in the process of alimentary instrumental conditioning. These bursts appeared at the stage of generalization in a number of neocortical areas in the interstimulus intervals at the background EA, which was at lower amplitudes (10-40 microV). Application of novel strategies developed by us to the primary analysis of EA realization (in particular, introduction of inhomogeneity factor and activation index) enabled estimation the amplitude-frequency inhomogeneity of EA, namely, HF bursts. The regional peculiarities of HF bursts were revealed by means of the technique, developed by us, that was based on expansion of the EA variations into a system of half-waves and construction of distribution maps on the basis of their parameters. The presented data verify our earlier findings obtained with the use of other techniques (fast Fourier transform analysis and factor analysis). These data testify to differential participation of cortical areas (even those that are within 3-5 mm of each other) in the spatiotemporal organization of potentials that is characteristic for a given learning paradigm.

Animals↗
PubMed1985

Correlation-spectral characteristics of cortical potentials in a wide frequency range in dogs in the process of elaborating a lever-pressing alimentary conditioned response.

Power spectra (PS) and cross-correlation coefficients (CC) of the background electrical activity (2-100 Hz) in different neocortical areas were studied in dogs in the state of quiet wakefulness (QW) and after elaboration of motor (lever-pressing) alimentary conditioned responses (CR). Regional differences revealed that in all the frequency bands, including the high-frequency frequencies, there was a significant increase of power in the frequency band of 61-100 Hz which was not the same in different cortical areas after CR elaboration. This shows that not only their information value of high frequency bioelectrical processes but also their neuronal origin is essential. After elaboration of the same CR, individual EEG peculiarities observed in the QW became levelled and the functional state became characteristic for this type of conditioning and was reflected in the distributions of CC and PS of the background activity.

Animals↗
PubMed1980

[Relationship between background and induced activity of cat auditory cortex neurons during elaboration of a defensive conditioned reflex to acoustic stimulation].

Using glass microelectrodes, the impulse activity of auditory cortex neurons was studied in chronic experiments on cats. It was shown that an increase in frequency of the background activity occurring in many neurons during conditioning was often observed prior to the appearance of conditioned motor reactions. Comparison of mean frequencies of the background activity and corresponding evoked activity shows, on the one hand, the nonlinear dependence between them and, on the other hand, the prevalence of activation reactions as compared with inhibitory ones. Some levels of background activity were distinguished corresponding to mean evoked activity frequency ranges. Background activity analysis performed prior to the presentation of the conditioned stimulus and after its cessation (aftereffect) shows that at stable conditioned reflex mean frequencies in these periods are close to each other.

Animals↗
PubMed1979

[Characteristics of the neuronal responses of the auditory zone of the cortex of awake cats in the resting state and during an elaborated defensive conditioned reflex].

The responses of 288 neurons with background activity in the first auditory cortex were investigated using glass microelectrodes in chronic experiments on cats at rest (123 neurons) and during elaboration of a defensive conditioned reflex to sound stimulation (165 neurons). At rest 43% of recorded neurons did not respond to the sound stimulus. Pronounced inhibition of background activity prevailed among responding neurons (about 60%). The conditioning caused an increase (to 72%) in proportion of neurons responsive to the sound stimulus, appearance of tonic reactions, as well as an increase in frequency of bursts and in proportion of activation type responses. It is suggested that these changes indicate the enhancement of neurons excitability in the zone under study during conditioning.

Animals↗
PubMed1979

[Dynamics of neuronal responses of the auditory zone of the cortex of wakeful cats during the process of elaboration of a defensive conditioned reflex to acoustic stimulation].

In chronic experiments on cats the neuronal responses (recording by means of glass microelectrodes) of auditory cortex I were studied during elaboration of a defensive conditioned reflex to a sound stimulus. During conditioning the biphasic reactions with a rather short-latent (50-100 ms) and more long-latent (400-500 and 800-900 ms) activation were predominant. The neighbouring neurons whose responses were recorded by the same microelectrode were involved into the activity more intensively. A differentiating stimulus in 70% of applications caused distinct changes in neuronal activity (predominantly of activation type). Analysis of the dynamics of responses of the same neuron during a great deal of combinations and its comparison with the formation of a motor reaction showed no direct correlation between the two events.

Animals↗
PubMed1978

[Background activity of neurons of the auditory zone of the cortex of awake cats in the resting state and during elaboration of defensive conditioned reflexes].

The results of statistical computer analysis of 366 realizations of the background activity of 181 neurons from the primary auditory cortex (field 50) in vigil cats (14) at rest and during defensive conditioning are presented. In both states the parameters of background activity in most neurons differed from completely random succession. The conditioning evoked a stable elevation of the frequency of background activity during interstimulus intervals, an increase in stability of the background impulsation as regards its average frequency and variation coefficients of the duration of interspike intervals, as well as an enhancement of the number of neurons showing different types of association between interspike intervals.

Animals↗
PubMedDate not supplied

Unit responses of the auditory cortex of waking cats at rest and after defensive conditioning.

In chronic experiments with glass microelectrodes responses of 288 spontaneously active neurons in the auditory cortex were investigated in cats at rest (123 neurons) and after defensive conditioning to sound (165 neurons). In the first situation 43% of neurons did not respond to acoustic stimulation. Most (about 60%) responses of the reacting neurons showed marked inhibition. Conditioning caused an increase (up to 72%) in the number of neurons responding to acoustic stimulation, the appearance of tonic responses, a severalfold increase in the amplitude of the responses, an increase in the number of responses of activation type, and stabilization of their form. The results point to increased excitability of neurons in this cortical area.

Animals↗
PubMedDate not supplied

A computer analysis of EEG-intersignal reactions during the development of motoric alimentary conditioned reflexes in dogs.

The background electrical activity of the neocortex in the interstimulus periods at the stage of generalization during the development of alimentary motor conditioned reflexes (CR) in dogs was the investigational object. It was characterized by the appearance of brief (0.1-0.3 sec) trains of high frequencies (HF), significantly exceeding the adjacent initial baseline in frequency and amplitude. The relative variance index which we had developed made it possible to distinguish this EEG phenomenon in the initial realizations of the background activity when they were inputted into a digital computer. It was not possible to evaluate the parameters of the HF chains by means of a spectral correlation analysis. Nonstandard techniques of computer analysis directed toward the decomposition of the EEG tracing into a system of oscillations and toward the obtaining of the corresponding amplitude-frequency distributions (maps) were developed by us for the purpose of accomplishing this objective. It was demonstrated that HF trains were localized in these maps in specific, quite compact regions.

Animals↗
PubMedDate not supplied

Study by nontraditional analytic methods of features of cortical potentials, taking high-frequency components into account, in dogs during instrumental learning.

A new method has been developed for the coding of EEG tracings which is an alternative to the classical spectral correlation analysis. This method has made it possible to compensate to a considerable degree for limitations which are unavoidable with the Fourier transform, and to obtain additional information regarding the form of the tracing, which reflects the fluctuations of brain potentials. The new system that has been presented for coding the EEG is, in our view, the most adequate (of the methods known to us) for identifying the individual features of the EEG, in terms of evaluating both their regional differences and similarities. The data obtained convince us once again of the real existence of high-frequency low-power components of the EEG, and their enhancement during instrumental learning in dogs (motor alimentary conditioned reflexes). In addition, data have been obtained pointing to the intensification in some regions of a slow-wave constituent; this has not been observed previously in carrying out a Fourier transform.

Algorithms↗
PubMedDate not supplied

Dynamic shifts in the parameters of the traditional frequency range of the EEG during learning in dogs.

The parameters of the electrical activity of various regions of the neocortex (NC) and the olfactory bulbs (OB) of dogs were studied by means of correlation-spectral analysis during the development of a food-dispenser paw pedal-pressing motor skill; a wide band of frequencies (1-100 Hz), which included both the traditional range (1-20 Hz) as well as high frequencies (HF), were used. Differences were demonstrated in the dynamics of the parameters in the NC and OB. The energy level of the potentials of the NC increased in the HF range (beta 3 and gamma), while in the OB it increased in the HF and alpha range. The coherence-phase characteristics of the NC potentials suggest that more stable (by comparison with resting wakefulness) temporal relationships between the oscillations not only within the limits of HF, but also in the alpha band, are formed in the presence of the developed skill. At the same time, greater phase shifts are characteristic for the interrelationships of the OB potentials and those of the NC, and the increase in coherence relates only to the HF range, whereas the oscillations of the traditional range are characterized by a decrease in coherence. The possible role of the alpha range (along with the HF) in the processing of information which supports appropriate behavior is stressed.

Animals↗