RESUMO
Facilitated influence of preliminary transection of the rat rubrospinal tract on motor activity and instrumental reflexes recovering after lesion of the red nucleus was more obvious after a chemical lesion rather than the electrolytic lesion. This seems to be due to remaining cerebello-thalamic fibres after a chemical lesion of the red nucleus. A preliminary destruction of the ventrolateral thalamic nucleus was shown to complicate switching of the motor activity in the rats with transected rubrospinal tract and lesioned red nucleus.
Assuntos
Núcleos Laterais do Tálamo/fisiologia , Atividade Motora/fisiologia , Núcleos Ventrais do Tálamo/fisiologia , Animais , Condicionamento Operante/fisiologia , Eletrólise , Feminino , Humanos , Ácido Quinolínico , Ratos , Núcleo Rubro/fisiologia , Medula Espinal/fisiologiaRESUMO
Recording of complex multicomponent oligo- and polysynaptic EPSPs revealed antidromic and synaptic responses in the same parietal cortical neurons which suggested a reciprocal link between pontine nuclei proper and the parietal association cortex in cats. Possible pathways and mechanisms of the ponto-cortical links, are discussed.
Assuntos
Neurônios/fisiologia , Lobo Parietal/fisiologia , Ponte/fisiologia , Sinapses/fisiologia , Potenciais de Ação/fisiologia , Animais , Gatos , Estimulação Elétrica , Eletrodos Implantados , Potenciais Evocados/fisiologia , Transmissão Sináptica/fisiologiaRESUMO
In anesthetised cats, antidromic activation as well as mono- and polysynaptic EPSPs to cortical motor stimulation, were shown in the parietal cortex's neurons. Functional significance of the cortico-cortical reciprocal connexion between the motor cortex and the parietal associative cortex, is discussed.
Assuntos
Córtex Motor/fisiologia , Neurônios/fisiologia , Lobo Parietal/fisiologia , Sinapses/fisiologia , Animais , Gatos , Estimulação Elétrica , Eletrodos Implantados , Microeletrodos , Transmissão Sináptica/fisiologiaRESUMO
In white non-strain rats with elaborated instrumental responses preliminary section of the rubro-spinal tract was shown to promote the compensatory restorative processes after the destruction of the red nucleus and the ventrolateral thalamic nucleus. Facilitation observed is considered to be a result of transfer of the motor activity to the cortico-spinal system due to activation of the inferior olive and the cerebellum.
Assuntos
Adaptação Fisiológica , Comportamento Animal/fisiologia , Núcleo Rubro/fisiologia , Núcleos Talâmicos/fisiologia , Animais , Condicionamento Operante/fisiologia , Feminino , Masculino , Transtornos dos Movimentos/etiologia , Transtornos dos Movimentos/fisiopatologia , Ratos , Núcleo Rubro/cirurgia , Núcleos Talâmicos/cirurgiaRESUMO
Collateral branching of efferent neurons' axons in the cat parietal associative cortex was studied with intracellular recording of antidromic activity. Specific features of the axon collaterals projecting onto the sensorimotor cortex, pontine nuclei proper and red nucleus, were revealed and described. Information arriving from the parietal cortex simultaneously at the above two motor structures suggests their interrelationship to be actualized through the axon collaterals of efferent neurons. This kind of functional interrelationship of the structures via axon branching of efferent neurons of the parietal cortex provides synchronous arrival of signals at the structures participating in motor integration.
Assuntos
Axônios/fisiologia , Neurônios Eferentes/fisiologia , Lobo Parietal/fisiologia , Animais , Axônios/ultraestrutura , Gatos , Estimulação Elétrica , Potenciais Evocados/fisiologia , Córtex Motor/fisiologia , Córtex Motor/ultraestrutura , Neurônios Eferentes/ultraestrutura , Lobo Parietal/ultraestrutura , Ponte/fisiologia , Ponte/ultraestrutura , Núcleo Rubro/fisiologia , Núcleo Rubro/ultraestruturaRESUMO
Excitatory responses of the parietal cortex neurons to stimulation of pontine nuclei, red nucleus and sensomotor cortex were found to prevail in cats. Most of the short-latency projecting neurons were localized in the surface layers of the cortex. Convergence ability of these neurons was revealed. Functional relationship of the parietal cortex with structures involved in organization of movement, i. e. sensomotor cortex, pontine nuclei and red nucleus, was found. Functional role of the parietal cortex in motor integration was discussed.
Assuntos
Tronco Encefálico/fisiologia , Córtex Motor/fisiologia , Neurônios/fisiologia , Lobo Parietal/fisiologia , Potenciais de Ação , Animais , Axônios/fisiologia , Gatos , Estimulação Elétrica , Microeletrodos , Tempo de Reação/fisiologiaRESUMO
Efferent neurons of the associative parietal cortex sending axons to the sensomotor cortex, red nucleus and pontine nuclei, were identified by means of antidromic stimulation in cats. Collateral branching of axons of the neurons projecting simultaneously to two of the above structures were studied using the impulse collision technique. Peculiarities of spatial distribution of efferent neurons in the cerebral parietal cortex were shown.
Assuntos
Lobo Parietal/fisiologia , Animais , Associação , Gatos , Vias Eferentes/fisiologia , Potenciais Evocados , Córtex Motor/fisiologia , Vias Neurais/fisiologia , Ponte/fisiologia , Tempo de Reação/fisiologia , Núcleo Rubro/fisiologia , Córtex Somatossensorial/fisiologiaRESUMO
Neuronal organization of the cerebello-cortical loop passing through the associative parietal region of the cat cerebral cortex was studied with the microelectrode recording technique. Specific characteristics of the cerebellar signals to various types of neurons of the parietal cortex projecting to the pontine nuclei proper, the red nucleus and sensomotor cortex, were revealed by responses of the cortical neurons to stimulation of the cerebellar nuclei. The neurons of parietal cortex were shown to respond most readily to stimulation of the nucleus dentatus (62.3%), nucleus interpositus (54.6%), and nucleus fastigii (20.6%).
Assuntos
Núcleos Cerebelares/fisiologia , Lobo Parietal/fisiologia , Animais , Mapeamento Encefálico , Gatos , Estimulação Elétrica , Córtex Motor/fisiologia , Vias Neurais/fisiologia , Ponte/fisiologia , Tempo de Reação/fisiologia , Núcleo Rubro/fisiologia , Córtex Somatossensorial/fisiologiaRESUMO
Peculiarities of topographical distribution of responses of the cat cerebral cortex to stimulation of cerebellar and thalamic (ventro-lateral and ventral anterior) nuclei as well as cerebello-thalamo-cortical projection system and comparison between the cerebellar and thalamic responses revealed differences in focal potentials evoked in pericruciate and parietal cortex. The latencies of the potentials, similarity in shape and in depth of reversion suggest that the cerebello-cortical responses in the pericruciate cortex are mediated through the thalamic ventro-lateral nucleus making synapses in III-IV cortical layers while responses in the parietal cortex--through the thalamic ventral anterior nucleus making synapses in more superficial layers.