Assuntos
Neurônios/fisiologia , Neurônios/ultraestrutura , Sinapses/fisiologia , Sinapses/ultraestrutura , Animais , Axônios/fisiologia , Axônios/ultraestrutura , Citoplasma/fisiologia , Citoplasma/ultraestrutura , Dendritos/fisiologia , Dendritos/ultraestrutura , Hipóxia-Isquemia Encefálica/patologia , Interneurônios/fisiologia , Interneurônios/ultraestrutura , Masculino , Microscopia Eletrônica , Córtex Motor/citologia , Córtex Motor/fisiologia , Córtex Motor/ultraestrutura , Pinocitose/fisiologia , Terminações Pré-Sinápticas/fisiologia , Terminações Pré-Sinápticas/ultraestrutura , Células Piramidais/fisiologia , Células Piramidais/ultraestrutura , Ratos , Ratos Wistar , Córtex Somatossensorial/citologia , Córtex Somatossensorial/fisiologia , Córtex Somatossensorial/ultraestruturaRESUMO
Using light and electron microscopy structural bases for intracellular, extracellular and integrative regulation of synaptic efficiency and neuron sensitivity were established in rat sensomotor cortex. Intracellular regulation is realized basically through modulation of postsynaptic components of the synapse, while extracellular one is provided by synaptic endings of "recurrent" axons on GABA-ergic relay and interneurons. Integrative regulation is realized by means of concentration of similar axonal terminals in restricted cortical area and arrangement of "neuromediatory" pool.
Assuntos
Neurônios/ultraestrutura , Sinapses/ultraestrutura , Animais , Histocitoquímica , Hipóxia/patologia , Isquemia/patologia , Microscopia Eletrônica , Córtex Motor/irrigação sanguínea , Córtex Motor/patologia , Córtex Motor/ultraestrutura , Neurônios/patologia , Esforço Físico , Ratos , Córtex Somatossensorial/irrigação sanguínea , Córtex Somatossensorial/patologia , Córtex Somatossensorial/ultraestrutura , Sinapses/patologiaRESUMO
The data we have by now accumulated on the cytoarchitectonics of the cerebral cortex, as well as published data, suggest that some of the neurons are structurally combined into compact clusters (ensembles, blocks), and that the majority of them participate in the construction of these clusters by directing the terminal branches of their axons to them. The collaterals of projection, associative, and callosal nerve cells, as well as the axons of interneurons which accomplish local interneuronal closures, can combine individual elements of the ensembles into a unified morphofunctional system. The collaterals of the axons of a block of neurons spread divergently to neurons disposed along the perimeter, while the axons of the latter converge reciprocally to the neurons of the cluster, forming a maximum (focus) of the arborization of the axonal terminals there; this makes it possible actively to isolate modules of nerve cells by accomplishing their self-assembly.
Assuntos
Córtex Cerebral/citologia , Neurônios/fisiologia , Animais , HumanosRESUMO
The light and electron-microscopy original data and other morphological and physiological findings reveal that a population of cortical neurones is gathered in compact cell clusters (blocks, ensembles, modules) and most of neurones participate in maintaining such modules by their axonal ramifications. Some elements of cell clusters may be joined by associative, callosal and projectional thalamic afferents. Authors' new findings are discussed in relation with corresponding literature data. The main attention is given to the self-organization of cortical modules.
