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T A Bragina

Publications and source records attributed to T A Bragina.

10 recordsLinked to original sources
PubMed1977

[Structural characteristics of the mediodorsal nucleus of the cat thalamus].

By means of the light and electron microscopy, construction and architectonics of neurons in the cat thalamus medio-dorsal nucleus are described. Differences in the neuronal body dimentions, their form, number of deferent dendrites and character of axonal branching made it possible to define 3 types of neurons. Applying the method based on retrograde axonal transport of exogenous horse-radish peroxidase, it was demonstrated that neurons of type II, contrary to the existing opinion, send their axons into the prefrontal cortex and, hence, are associative-projective. Ultrastructural difference of axonal terminals, differences in the form and size of synaptic vesicles made it possible to reveal 5 types of presynapses.

Animals↗
PubMed1976

[Experience with the use of horseradish peroxidase for light and electron microscope studies of interneuronal connections].

By the method based on a retrograde axonal transport of exogenous horseradish peroxidase (HRP), the origins of afferentation of the motor cortex of adult cats, kittens and albino rats were studied. HRP-positive neurons were found by light and electron microscopy in the somatosensory cortex (C1) of the ipsilateral hemisphere and in the portions of the cortex of the contralateral hemisphere which were symmetrical to the site of injection of HRP. The disposition of neurons, marked by HRP, in the Vth layer of the motor cortex suggest that these neurons may send their axons into the bundles of comissural fibres going to the motor cortex of the opposite hemisphere. This method considerably expands possibilities of revealing the origins of afferentation of the investigated portion of the nervous system and allows more complete and reliable investigation of interneuronal connections.

Animals↗
PubMed1975

[Ultrastructural characteristics of axon terminals of the posterior lateral nucleus of the thalamus in the cat].

Two kinds of axon terminals: fine M-terminals with the diameter up to 2 mkm and large K-terminals with the diameter up to 6 mkm were found in electron microscopic study of the posterior lateral nucleus of the cat's thalamus. M-terminals comprising 88% of the total amount of the axon terminations under analysis are characterized by a great amount of densely packed light round synaptic vesicles and solitary mitochondria. These terminals form asymmetrical type of contacts in which the post-synaptic network is distinguished with a high degree of osmiophilia. The K-terminals contain a few rarely distributed round light synaptic vesicles and many mitochondria which are disposed in the central part of the termination. These terminals form a symmetrical type of synaptic contacts with poorly pronounced active zones in these formations. In axo-axonal contacts between the described kinds of terminals the K-terminals always serve as a presynapse. After extirpation of the sincipital cortex M-terminals underwent degeneration.

Animals↗
PubMed1975

[Changes in the synaptic vesicles of cat motor cortex axon terminals upon stimulation].

The relation of the synaptic vesicle size to the distance between the vesicle and the synapse active zone was studied in the axon terminals at the motor cortex neuron spines and dendrites of resting cats (under moderate barbiturate anesthesia) and after prolonged repetitive stimulation of the somatosensory SII area. Thes sizes of the vesicles belonging to any of the three strata observed in the terminal section profile under the electron microscope were registered as a decrementing variation sequence. The predominance of small vesicles in stratum I adjoining to the synapse active zone was found by means of the statistical analysis (symbol criterion and criterion chi2), both in the control and experimental material. A significant gradient of the vesicle size diminution from peripheral stratum III to stratum I as well as vesicle size decrease both in stratum I and intermediate stratum II in comparison with the control developed after the cortico-cortical projection stimulation. The functional role of this phenomenon is discussed.

Animals↗