Brain Behav Evol 47:23–32īurns S, Wallman J (1981) Relation of single unit properties to the oculomotor function of the nucleus of the basal optic root (accessory optic system) in chickens. Brain Res 515:343–346īredenkötter M, Engelage J, Bischof H-J (1996) Visual system alterations in white zebra finches. Ann Rec 190:605–606īredenkötter M, Bischof H-J (1990) Ipsilaterally evoked responses of the zebra finch visual wulst are reproduced during ontogeny. ![]() Exp Brain Res 28:73–84īrecha N, Karten HJ (1978) Projection of the accessory optic nuclei and vestibular nuclei upon the oculomotor nuclear complex in pigeon. J Comp Physiol A 163:329–337īrauth SE, Karten HJ (1977) Direct accessory optic projections to the vestibulo-cerebellum: a possible channel for oculomotor control systems. The unwillingness of white birds to respond with optokinetic response in bright daylight may be due to a substantial lack of inhibition within the visual system as demonstrated earlier, which may enhance the sensibility to glare.īischof H-J (1988) The visual field and visually guided behavior in the zebra finch ( Taeniopygia guttata). We conclude that the altered wiring of the visual system of white birds has no influence on accessory optic system function. In bright daylight, white birds did not show optokinetic responses. Its increase with illumination level followed Fechner’s law and reached a plateau at about 560 Lux. The upper velocity threshold was higher with temporal to nasal movements in monocularly exposed birds and symmetrical with binocular exposure. The highest stimulus velocity eliciting an optokinetic response (upper velocity threshold) was dependent on stimulus direction and illumination level, but was not different between the colour morphs. We investigated here the effect of rotational optic flow on the optokinetic response in wild type and white zebra finches. in a rotating drum lined with vertical stripes. The optokinetic response is elicited by rotational optic flow, e.g. It is processed by the accessory optic system in all vertebrates. The main findings were that in 10-day-old nestlings, T lymphocytes were sensitive to PHA stimulation, while B lymphocytes were unable to respond to srbc that hematocrit was approximately 30% lower than in mature birds that precision of leucocrit determination was heavily technique-dependent that endogenous steroids increased the total leucocrit, while exogenous steroids increased heterophil and decreased lymphocyte counts, thus increasing H:L that dexamethasone exposure temporarily reduced growth rate that CT exposure stimulated germinal cell development in the bursa of Fabricius and that dexamethazone and CT exposure were associated with decreased splenic white pulp formation.Optic flow is a main source of information about self movement and the three-dimensional composition of the environment during locomotion. ![]() The remaining birds were vaccinated with sheep red blood cells (srbc) to evaluate antibody-mediated immunity. ![]() At 9-10 days of age, a phytohemagglutinin (PHA) skin test of immune function was conducted at 11 days of age, five chicks from each group were euthanized for gross and histopathologic examination of immune system organs. From 6 to 10 days of age, zebra finch nestlings (Taeniopygia guttata) were given daily oral doses of Oil Sands tailings water (CT), an immunosuppressant dexamethasone, or phosphate-buffered saline. In this study several assays of immune function in young passerines are validated and compared. Avian species, through their trophic relationships, may represent ideal indicators for assessing environmental health.
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