[The effect of acute alcohol administration on auditory evoked potentials in altricial nestlings during the development of natural behavior].

Acute ethanol influence on field L auditory evoked potentials (AEP) was studied in 4-8-days-old altricial nestlings of pied flycatcher. Nestlings were presented with tone pips related with the realization of natural behaviour (2.0 and 5.

[Role of a species-specific acoustic environment in the development of hearing in nestlings].

Main parameters were studied of the acoustic evoked potentials (EPs) from L field of the caudal neostriatum of altricial nestlings of 2-8 days to pure tones in the range of species-specific signals. It has been established that auditory EPs to the tones of different frequencies differ by the terms of appearance and the degree of maturity. At every of the revealed stages of the auditory ontogenesis, including the stage of completely formed auditory sensitivity, such parameters of auditory EPs, as latencies of different phases, amplitude-temporal pattern and the course of recovery curve are different for the tones of different frequencies.

[Age dynamics of visually guided behavior and visual evoked potentials of altricial nestlings].

Comparative study has been carried out of factors of organization of visually guided feeding behaviour (observation method) and the degree of maturity of the visual mechanisms by the criterion of Wulst EPs formation and of their recovery cycles in normally developing and visually deprived nestlings. In has been established that during the period following the opening of the eyes (5-9th day) the feeding behaviour is connected with diffuse photo-sensitivity of visual mechanisms. Diffuse photo-sensitivity fully provides for natural feeding behaviour at the corresponding stage of development of visual functions.

[Relation between the defensive behavior of altricial nestlings and the parameters of an alarm signal. Neuroethologic approach].

The acoustic organization of the defensive behaviour was studied in Pied Flycatcher nestlings. Electrodes were chronically implanted into the field L and the neck muscles for auditory EPs and EMG recordings. A well developed defensive reaction which under natural conditions is elicited by species-specific alarm call, could be artificially provoked by monotonal 4.

[Formation of visual evoked potentials and development of visually guided behavior in the Ficedula hypoleuca nestling].

Age dynamics of evoked potentials (EPs) of Wulst area of the dorsal hyperstriatum (functional analogue of mammalian visual cortex) was investigated in 2-7 days old nestlings. EPs in response to light stimuli, with the duration and intensity imitating natural alimentary signals for 5-7 days-old nestlings, were recorded parallel with the behaviour. It was found that the development of the visual system in precocious nestlings became completed in postembryonal ontogenesis.

[Auditory evoked potentials and acoustically-directed behavior of nestlings].

Characteristics of auditory evoked potentials (EP) were studied in 1.5 to 7.5 days old Pied Flycatchers nestlings (Ficedula hypoleuca) with chronically implanted electrodes in the field L (analogue of the mammal's auditory cortex).

[Visual evoked potentials of fledglings to ecologically significant stimuli].

A study was made of the structure of evoked potentials in the Wulst of the dorsal hyperstriatum in five- to eight-day old nestlings in response to ecologically determined visual stimuli significant for the alimentary behaviour, within the range of their intensity natural fluctuation. It was established that the parameters of the visual evoked potentials correlate with the rate of behaviour manifestation, which depends on the level of alimentary motivation. At a low motivation level (and under Nembutal anaesthesia), latencies of all response components depend on the energetic parameters of the stimuli and to a maximum degree so -- the primary component latencies.

[Development of species specific acoustic sensitivity in hole-nester fledgelings].

A study was made of acoustic sensibility of hole nestlings to species-specific signals of adult birds. It has been established that the final formation of sensibility to such signals is not completed in the embrional period of development, but continues, at least during the first half of life in the nest. In the embrional period, the formation of sensibility is concluded only within the spectrum of the "alimentary" signal complex, providing for adequate alimentary behaviour of the nestlings immediately after hatching.

[Role of natural sensory factors in organization of feeding behavior using fledgling development as an example].

A change in the composition of natural sensory stimuli, triggers of the alimentary functional system of Muscicapa hypoleuca nestlings, was studied throughout their nest life. In the first five days the alimentary reaction is elicited by a complex of acoustic stimuli. From the fifth to the eighth day the reaction appears in response to a momentary change of illumination.