Effects of an early postnatal hypoxia on the development of spontaneous head movements in rabbits.
The early detection of minor brain dysfunctions resulting from perinatal hypoxia is very important since the prognosis of the affected children can be substantially improved by a prompt treatment. Therefore, this paper deals with the influence of an early postnatal hypoxia on the postnatal development of spontaneous head movements and the influence of the visual system on head movements in normal and hypoxic disturbed ontogenesis. Head movements were recorded in 12 unrestrained spontaneously behaving alert rabbits from 6 litters with the sensor coil technique. One rabbit of each litter was exposed to a single acute hypoxia (FiO2 = 0.05) for 3 h at the 1st day of life. The siblings were regarded as a control group. The most important characteristic of the postnatal development of the head movements is the forming of horizontal saccadic movements during the second postnatal week and their perfection by an increase in mean velocity up to the 20th postnatal day. The early postnatal hypoxia leads to a decrease of the mean velocity of saccadic head movements. But this is only true if the rabbits have open eyes. Blind-folding the rabbits of the control group during the recordings was followed by a decrease of the mean velocity (14th and 20th postnatal day) and the amplitude (at the 20th postnatal day) of the saccadic head movements. In contrast to the non-hypoxic rabbits, blind-folding had no perceptible influence on head movements in hypoxic rabbits until the 3rd postnatal week. Our results suggest that early postnatal hypoxia causes a
Woldag
H
H
University of Leipzig, Institut of Pathological Physiology, Germany.
Tegetmeyer
H
H
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D005123:Eye / Q000254:growth & development; D006257:Head; D000860:Hypoxia / Q000523:psychology*; D009068:Movement / Q000502:physiology*; D009799:Ocular Physiological Phenomena; D011817:Rabbits; D012044:Regression Analysis; D012438:Saccades / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology