Influence of Natural Asymmetric Embryonic Visual Afferentation on the Neuronal Activations in the Caudomedial Mesopallium during the Freezing Response in Altricial Nestlings.

The study was designed to investigate the role of asymmetric prenatal visual stimulation on the activation of caudomedial mesopallium (CMM) neurons in nine-day-old pied flycatcher nestlings during auditory-guided freezing. Four groups of nestlings were studied: groups 1 and 2 included nestlings with normal vision and visually deprived, respectively, that were incubated and hatched in normal light environment; groups 3 and 4, nestlings with normal vision and visually deprived, respectively, that were incubated and hatched in the dark. The eyes of visually deprived nestlings were covered with non-transparent cups 2 h before the experiment. C-Fos expression was studied. It was shown that densities of neurons activated during freezing response differed in right vs. left CMM only in the group of visually deprived nestlings incubated under light. This suggests that the presence or absence of the asymmetric embryonic visual afferentation may result in the development of different strategies of the visual system integration into defense behavior.

[Wulst Activation in Pied Flycatcher Nestlings in Feeding Behavior Induced by Patterned Visual Stimulus].

Immunohistochemical detection of c-Fos was used to study the transcriptional activation in two higher visual centers (Wulst area and Entopallium) of 12-day-old pied flycatcher (Ficedula hypoleuca) during the realization of feeding behavior guided by patterned visual stimulus, simulating the species-specific one. Activation was compared in 4 groups of nestlings. Control group was not subjected to any experimental influence. In binocular, right-field (deprivation of the left eye) and left-filed (deprivation of the right eye) groups the vision feeding responses were provoked, reinforced and evaluated. It was shown that the visual afferentation from the right eye was more significant for the organization of early feeding behavior guided by a moving patterned visual stimulus as compared with the afferentation from the left eye. Feeding behavior induced activation of c-Fos expression only in neurons of the higher center of thalamofugal system--Wulst area. The comparison of transcriptional activation in different groups revealed the significant increase of c-Fos induction related with feeding behavior only in the left hemisphere and only in binocular and right-field groups.

[EEG in altricial pied flycatcher nestlings during the functional sates related with natural behavior cycle].

Electrical brain activity accompanying various forms of behavior was studied in 11-day-old pied flycatcher nestlings. Wavelet analysis of EEG, recorded from symmetrical areas of caudomedial nidopallium (higher avian auditory center) during rest, passive and active wakefulness and movements showed that the major rhythmical EEG component was confined to low-frequency range in all four states. The significant difference from other states was observed only during movements: spectral power in the range of 1-3 Hz decreased while that in the range of 5-20 Hz--increased. The range of 3-5 Hz revealed, in all functional states, the interhemispheric asymmetry of spectral power that could be due to asymmetrical embryonic development of avian visual projections. Active wakefulness and movements were characterized by high positive correlations between spectral power in right and left hemispheres. During rest this correlation was negative. The correlation values during passive wakefulness and rest were rather low that could indicate disintegration of neural connections.

[Visual input affects the expression of the early genes c-Fos and ZENK in auditory telencephalic centers of pied flycatcher nestlings during the acoustically-guided freezing].

The present study analyzed expression of transcriptional factors c-Fos and ZENK in 9-day-old pied flycatcher nestlings' (Ficedula hypoleuca) telencephalic auditory centers (field L, caudomedial nidopallium and caudomedial mesopallium) involved in the acoustically-guided defense behavior. Species-typical alarm call was presented to the young in three groups: 1--intact group (sighted control), 2--nestlings visually deprived just before the experiment for a short time (unsighted control) 3--nestlings visually deprived right after hatching (experimental deprivation). Induction of c-Fos as well as ZENK in nestlings from the experimental deprivation group was decreased in both hemispheres as compared with intact group. In the group of unsighted control, only the decrease of c-Fos induction was observed exclusively in the right hemisphere. These findings suggest that limitation of visual input changes the population of neurons involved into the acoustically-guided behavior, the effect being dependant from the duration of deprivation.

Involvement of Wulst neurons in hiding reaction of pied flycatcher nestlings with different visual afferentation.

We studied transcriptional activity in the higher avian center visual system (Wulst area) in acoustically guided defensive behavior in visually deprived and non-deprived nestlings to evaluate the effects of visual afferentation on functional involvement of visual structures in acoustically guided defensive behavior. Exclusion of visual afferentation from already formed defensive behavior did not significantly change immunoreactivity of Wulst neurons, which attests to substantial contribution of other, non-visual, activating influences. Limitation of visual afferentation during the formation of defensive behavior decreased immunoreactivity of Wulst neurons. Dendritic sprouting in Wulst neurons of visually deprived nestlings unable to promote the formation of complex interneuronic interactions.

[Activation of tectofugal visual system of the pied flycatcher nestlings at early developmental stages of feeding behavior guided by diffuse photosensitivity].

Immunohistochemical detection of c-Fos in serial frontal sections of the brain of Pied flycatcher nestlings was used to map the sensory structures involved in early forms of feeding behavior. The c-Fos content was quantitatively analyzed in the higher structures of thalamofugal (Wulst area) and tectofugal (entopallium) visual pathways during visually-guided feeding behavior in 6-day-old nestlings at the stage of diffuse photosensitivity. Induction of c-Fos was not observed in the Wulst area which is known to be involved in the feeding integration in adult bifoveal birds. Induction of c-Fos was detected in the ventral area of entopallium containing neurons that are, according to literature, sensitive to a luminosity change. In the entopallium of 6-day-old nestlings, asymmetry in the evoked c-Fos expression was observed, probably reflecting the asymmetry of the visual projections originating in the embryonic period.

Effects of visual deprivation on the development of auditory sensitivity during formation of the freezing reaction in pied flycatcher nestlings.

Recording of evoked potentials from the higher center of the auditory system - field L of the nidopallidum - was used to study the formation of auditory sensitivity in normally developing and visually deprived pied flycatcher nestlings aged 6-9 days. Restriction of visual afferentation was found to produce significant reductions in the absolute threshold of auditory evoked potentials in the frequency range of the species-specific food call (1-3 kHz) during the period at which vision acquires a role in providing sensory support for feeding behavior in control nestlings (six days). In the frequency range of the species-specific alarm call (4-5 kHz), the thresholds of auditory evoked potentials were significantly lower than those in controls during the period at which vision acquires a role in providing sensory support for defensive behavior (8-9 days). Taking account of previous data showing decreases in the efficiency of acoustic signals in evoking freezing reactions in visually deprived nestlings, it is suggested that defensive behavior develops not simply as a response to the acoustic alarm call or tones imitating it, but as a system whose complete formation and functioning require integration of a series of factors, including visual afferentation.

[Molecular characteristics of cyclodextrin molecules, obtained in studies of the properties of their solutions].

Molecules of three cyclodextrins have been studied by molecular hydrodynamics methods in water, dimethylformamide, and dimethylsulfoxide. The molecular masses have been estimated, and the values correlate well with the calculated values. The hydrodynamic radii of cyclodextrin molecules have been also determined. The experimental data have been compared with theoretical calculations for toroidal molecules. The experimental data may be reconciled with the theoretical on the assumption that solvent molecules are adsorbed on the external surface of cyclodextrin molecules.

[Visual deprivation affects the development of auditory sensitivity during the period of maturation of freezing response in pied flycatcher nestlings].

Recording of evoked potentials (EP) from the higher auditory center of birds field L of the nidopallium was used to study the development of the auditory sensitivity in normally developing vs visually deprived pied flycatcher nestlings aged 6-9 days. The visual deprivation was shown to induce a significant decrease in the absolute auditory EP thresholds in the frequency range of species-typical food call (1-3 kHz) during the period corresponding to the time of the vision involvement into the feeding behavior in the normal young (6 days post-hatching). In the frequency range of species-typical alarm call (4-5 kHz), EP thresholds in visually deprived nestlings were significantly lower than in the control birds during the period corresponding to the time of the vision involvement into the defense behavior of the latter (8-9 days post-hatching). With account made for the previous data demonstrating the decrease of efficiency of acoustic signals provoking freezing in visually-deprived nestlings, it is reasonable to suggest that defense behavior develops not just as a response to alarm call or imitating tone pips, but as a whole system, whose norma maturation and functioning requires integration of numerous factors visual afferentation being one of them.

[Prenatal acoustic stimulation and feeding behavior of Japanese quail chicks (Coturnix coturnix japonica)].

Effects of a prenatal rhythmic tone on behavior of Japanese quail chicks were studied on the next days after hatching. The acoustically stimulated chicks demonstrated a significantly more frequent following response, feeding reaction and comfortable behavior when hearing the tone as compared with their controls. Bandwidths stimulating this or another behavior were determined.

[The role of visual afferentation in the development of early defense behavior of pied flycatcher nestlings].

The development of defense behavior in normal and visually deprived pied flycatcher nestlings was studied in the wild. It was demonstrated that the young deprived of the visual afferentation did not develop the freezing posture. In the majority of cases, specific alarm call suppressed begging in visually deprived nestlings less effectively than in the control ones. Visually deprived nestlings could not discriminate between the alarm call and other rhythmically organized acoustic signals even though the latter effectively suppressed begging.

Half-life of leu-enkephalin in the serum of infants of the first year of life on different types of feeding: relationship with temperament.

The half-life of leu-enkephalin in the serum of infants aged under 1 year is significantly shorter than in adults. In girls leu-enkephalin half-life is significantly longer than in boys. The half-life of leu-enkephalin is different in infants on breast and formula feeding. Nine characteristics of temperament in infants of the first year of life were determined using EITQ and ITQ questionnaires. Serum leu-enkephalin half-life directly correlated with temperament characteristics (activity, perception, threshold), but not with the level psychomotor development.

[Increasing selectivity of defense behavior during development of pied flycatcher nestlings]. / Rost selektivnosti oboronitel'nogo povedeniia v ontogeneze ptentsov mukholovki-pestrushki.

The development of defense reaction was studied in the wildlife and experimentally in 7 broods of altricial pied flycatcher (Ficedula hypoleuca) nestlings. Field studies demonstrated that passive-defense response first appeared on the 4th day of the nest life. It developed from the cessation of begging in young relatively satiated nestlings to characteristic freezing response independent of the level of feeding motivation in older nestlings. Older nestlings also acquire the defense reaction in response to novel visual stimuli. The efficiency of the natural stimulus for defense behavior (species-specific alarm call) nongradually changes during the nest life attaining the 100% level only on the 11th posthatching day. During the initial phase of defense behavior development, the reaction can be induced by different rhythmically organized stimuli. Later it becomes considerably more selective and other rhythmic and acoustic signals become much less effective than the alarm call.

[Visual afferentation deficit during diffuse photosensitivity period in nestlings affects morphogenesis in Wulst neurons]. / Defitsit zritel'noi afferentatsii v period diffuznoi fotochuvstvitel'nosti ptentsov vliiaet na morfogenez neironov Wulst.

Golgi-stained preparations were processed with computerized morphometry to study the effect of the deprivation (eyes covered with nontransparent caps) on the development of neurons in the Wulst (the structure analogous to mammalian visual cortex) of pied flycatcher nestlings. Six-day-old nestlings that have only one form of the visual perception--diffuse photosensitivity--were studied. In the previous paper [Korneeva et al., 1994] in was shown that the Wulst of 6-day-old nestlings consisted of non-differentiated neurons and stellate-like cells at different stages of maturation; the latter group was subdivided into more- and less-mature cells. This work proved that even a 1.5-day-long deprivation (actual duration being counted off from the moment of appearance of the first retinal photoreceptors at the age of 4.5 days) resulted in significant changes in the geometry of stellate-like neurons. The changes in less-mature cells were predominantly destructive (decline of all quantitative indices of a cell, including the significant decrease in the total length of dendrites, maximal radius of the dendritic field and cell branching index), while the changes in more-mature cells were constructive (increase in all quantitative cell indices, including statistically significant increase in the soma section area, total length of dendrites, maximal radius of dendritic field and the number of foci of maximal branching). Different reactions of these cell types to the limitation of visual afferentation may be connected with differences in the afferent inflow to less- and more-mature cells or/and with different maturational stages of these neurons at the onset of deprivation.

[The morphogenesis of Wulst neurons in the pied flycatcher under conditions of limited afferent inflow]. / Morfogenez neironov Wulst mukholovki-pestrushki v usloviiakh ogranicheniia afferentnogo pritoka.

Golgi preparations of the pied flycatcher Wulst region (the structure analogous to the mammalian visual cortex) were analyzed using the method of computerized morphometry, to study the influence of visual deprivation on the development of different types of neurons selected previously. Deprivation was accomplished by covering the young's eye with nontransparent caps. The experiments were carried out in 10-day-old nestlings (the onset of patterned vision) and 13-day-old nestlings (functioning patterned vision). In 10-day-old nestlings, the deprivation produced constructive changes in dendritic apparatus of projective stellate cells (among them, the most pronounced was more than three-fold increase in the number of foci of maximal branching) practically not affecting the small stellate-like cells. In 13-day-old nestlings, cells belonging to all selected cell types underwent destructive changes: their quantitative characteristics were decreased as compared to those in control nestlings. A large number of tree-like neurons were revealed in the Wulst in the deprived 10-day-old nestlings while in the control age-matched nestlings they were virtually never found. This phenomenon may be explained by the increased affinity to impregnation evoked by deprivation-induced biochemical changes in the tree-like neurons or to increase in their number. In the latter case, the phenomenon may be considered as compensatory, directed at the establishing of contacts with nonvisual afferents.

[A quantitative morphological study of the effect of partial visual deprivation on the formation of 2 types of Wulst neurons in pied flycatcher nestlings]. / Kolichestvennoe morfologicheskoe issledovanie vliianiia chastichnoi zritel'noi deprivatsii na formirovanie dvukh vidov neironov Wulst ptentsov mukholovki-pestrushki.

Neurons of the Wulst area (analogous to mammalian visual cortex) were studied with the method of computerized morphometry (6 parameters) in frontal Golgi-stained sections of pied flycatcher nestlings which were binocularly deprived since the age of 1-1.5 days post-hatching. The current study was focused on two types of neurons: spiny stellate and small spineless stellate-like cells. It was found that the visual deprivation not only slowed down the morphogenesis of these neurons but also caused the constructive changes--increase in the number of foci of maximal dendrite branching--in spiny stellate neurons which we had earlier defined as projective cells. Changes in small spineless stellate-like neurons (earlier defined as intercalate cells) were of, mostly, opposite direction. In the latter neurons we observed a reduction of the number of dendrites and dendrite branches. Opposite changes in different cell groups caused by the limitation of sensory input may, on the one hand, point to a difference in functional connections of ascending afferent fibers with different types of neurons, and, on the other hand, indicate a different degree of the influence of visual experience on the development of these neurons.

Sensory information--the major factor of ontogeny.

On the basis of their own data authors postulate that the increase in sensory input during early ontogeny results in a delay in the development of the sensory systems formed earlier. In connection with this, the sensory basis of behavioral patterns becomes ineffective, causing their reorganization and the appearance of new forms of behavior. Limitation of sensory input during during the critical periods of development stimulates the accelerated manifestation of behavioral patterns. However, this acceleration also has long-lasting negative effects - alterations in the process of learning and memory in adult animals.