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The onset of synaptogenesis was studied in the temporal cortex of rat fetuses whose age ranged between 15 and 19 days of gestation. First synapses were found at a surprisingly early stage of cortical development: on day 16. These contacts showed relatively few vesicles and very inconspicuous membrane-thickenings. They were located in the marginal layer,(More)
The study of the postnatal maturation of the ventral cochlear nuclei (VCN) and the dorsal cochlear nuclei (DCN) was carried out on the cat by means of recordings of the extra-cellular neuronal activity. At birth it is already possible to obtain toneburst responses in the VCN and DCN. At this age the responses are characterised by a small number of spikes(More)
Rat fetuses received tritiated thymidine on one of each of the following days of gestation: 9, 10, 11, 12, 13, 14 and 16. Animals were sacrificed on day 1 post partum. Perpendicular and tangential sections including temporal cortex were studied by electron microscopy and light microscopic autoradiography. Our results suggest that the formation of(More)
Early cortical neurogenesis and synaptogenesis are discussed with reference to observations made in fetal and postnatal rat temporal cortex. Thymidine autoradiography was used to determine the time of origin of cortical neurons, particularly of layer I. Earliest neurons--CRs--form between FD 12 and 15, whereas the period of maximal formation of layer I(More)
Myelinated cell bodies of spiral ganglion in kittens during development can first be distinguished by light microscopic observation at the end of the first postnatal week. By mean of electron microscopic observation, the first signs of myelinated perikarya can be observed around the time of birth. Myelination is preceded by the ensheathment of the ganglion(More)
The maturation of the stato-acoustic nerve in the cat was studied by light and electron microscopy from the fetal stage to the adult. Measurement of the outer diameter of the fibers and the study of the myelination process revealed that myelination begins earlier for the vestibular nerve than for the cochlear nerve: by the fifty-third day of gestation 64%(More)
A study of the pathways and ascending vestibular projections was carried out in the cat after unilateral injection of tritiated leucine into the rostral vestibular complex. Radioautographic analysis revealed a gradual decline in the density of labeling as ascending fibers were found to progress towards more rostral relays. The pathways and projections were(More)
Newborn rats received an intracisternal injection of 6-hydroxydopamine (100 micrograms) within 16 h after birth. Treatment effects upon noradrenaline uptake (with or without desmethylimipramine pre-incubation), endogenous noradrenaline, dopamine, and serotonin were biochemically assayed. Noradrenaline uptake and endogenous noradrenaline content were(More)
Localized cooling was used in the search for vestibulothalamic pathways and a study was made of its effect on the activity of the thalamic neurons brought into action by stimulation of the vestibular nerve. Two cell populations were identified by their distinctive latencies in the ventral part of the posterior thalamus. Short latency responses were(More)