title: Postnatal ontogeny of evoked neuronal responses in the substantia nigra of the cat.
abstract: Single unit extracellular responses evoked by striatal, cortical, and somatosensory stimulation were recorded in substantia nigra (SN) neurons of kittens (1-70 days of postnatal age) and adult cats. Neuronal responses to stimulation of each site were obtained throughout postnatal development. However, 4 major developmental shifts in the response of neurons were found: (1) the responsiveness of neurons to orthodromic activation increased with age; (2) the signs of the initial responses of neurons to orthodromic activation increased with age; (2) the signs of the initial responses of neurons to caudate and cortical stimulation changed with age (excitatory and inhibitory responses in kittens vs almost entirely inhibitory responses in adults); (3) the the response latencies of neurons decreased with age; (4) nigral neurons that were activated antidromically by stimulation of nigrostriatal axons showed age-related decreases in refractory periods and increases in conduction  velocities.
mesh_terms: D000367:Age Factors; D000818:Animals; D002415:Cats; D002421:Caudate Nucleus / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology; D005071:Evoked Potentials; D005073:Evoked Potentials, Somatosensory; D009433:Neural Inhibition; D009434:Neural Pathways / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013378:Substantia Nigra / Q000254:growth & development* / Q000502:physiology