Post-natal development of the cerebello-cerebral projection in kittens.
Post-natal development of the cerebello-cerebral response was investigated in 126 kittens from birth to 142 days of age by analysis of laminar field potentials in the cerebral cortex; the thalamocortical projection mediating the cerebello-cerebral response was examined on four new-born and three one-month-old kittens by means of anterograde axonal transport of horseradish peroxidase. A marked response was evoked in the frontal motor cortex from birth and an appreciable response could be evoked in the parietal association cortex at 2 days after birth. The latency of response in the frontal cortex decreased sharply from birth till 3 weeks of age whereas that in the parietal cortex remained almost unchanged until 2 weeks of age. Maturation of the cerebello-cerebral projection, in every respect, proceeds earlier in the frontal cortex than in the parietal cortex. The cerebello-cerebral response in kittens at any age, like in adult cats, consisted of two types of elementary responses: one which is characterized by a surface positive-depth negative (s.p.-d.n.) wave and the other which is characterized by a surface negative-depth positive (s.n.-d.p.) wave. The response in the frontal cortex was a sequential occurrence of the two waves while the responses in the parietal cortex was a pure form of the s.n.-d.p. wave. Two types of thalamocortical projections corresponding to the two types of elementary responses were revealed: one is the projection mainly onto layer I which appears to mediate the s.n.-d.p. wave and the other is the projection mainly onto layer III which appears to mediate the s.p.-d.n. wave. Development of the cerebello-cerebral response and changes in the terminal distribution of the thalamocortical projection during maturation are consistent with the principle of ontogenesis of the mammalian neocortical organization, i.e. ascending sequential maturation.
D000375:Aging; D000818:Animals; D002415:Cats / Q000254:growth & development*; D002529:Cerebellar Nuclei / Q000254:growth & development* / Q000502:physiology; D004558:Electric Stimulation; D005071:Evoked Potentials; D005625:Frontal Lobe / Q000254:growth & development* / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D010296:Parietal Lobe / Q000254:growth & development* / Q000502:physiology; D013787:Thalamic Nuclei / Q000502:physiology