ABSTRACT
In rabbit experiments after cross-cutting the sciatic nerve with its subsequent perineural suture, the authors studied whether the structure of injured nerve fibers could be recovered on exposure to an impulse magnetic field (IMF) of high intensity (1.2 T). On exposure to IMF, the processes of nerve fiber myelinization were found to proceed much more rapidly in the rabbits operated on and the area of a connective tissue scar showed a more direct growth of nerve fibers of the center to the periphery. Light optic microscopy indicated that IMF of the intensity used produced no damaging effects on nerve tissue.
Subject(s)
Magnetics , Nerve Regeneration/physiology , Sciatic Nerve/physiology , Animals , Male , RabbitsABSTRACT
The cut sciatic nerve trunk was sutured perineurally to study in chronic rabbit experiments of the neuromuscular functional recovery upon the exposure to impulse magnetic field with the intensity 1.2 T. Nonexposed animals served control. Myographic activity of reinnervated crural muscles in the irradiated animals recovered two times more rapidly compared to the controls, so did motor function of the limb operated on. It is inferred that impulse magnetic field produces therapeutic and preventive effect on neurodystrophy resultant from the nerve dissection.
Subject(s)
Magnetics/therapeutic use , Peripheral Nerves/physiology , Animals , Electromyography , Microsurgery , Nerve Regeneration/physiology , Peripheral Nerve Injuries , Peripheral Nerves/surgery , Rabbits , Sciatic Nerve/injuries , Sciatic Nerve/physiology , Sciatic Nerve/surgery , Time FactorsABSTRACT
In experiments with unilateral injections of horseradish peroxidase microdoses into the dorsal sites of external g. proreus. using the method of retrograde axonal transport, labeled neurons have been revealed ipsilaterally in the singular cortex of telencephalon, in amygdala and thalamic structures of the brain (n.medio-dorsal nucleus, anterior group of nuclei and intralaminar nuclei). The role of the direct projections discovered to the prefrontal cortex in the formation of emotional component of pain is discussed.
Subject(s)
Neurons, Afferent/anatomy & histology , Temporal Lobe/anatomy & histology , Animals , Axonal Transport , Cats , Emotions , Horseradish Peroxidase , Neurons, Afferent/physiology , Pain/physiopathology , Pain/psychology , Temporal Lobe/physiology , Thalamic Nuclei/anatomy & histologyABSTRACT
When studying cytoarchitectonics of the midbrain periaqueductal gray (PAG) in cat four areas were distinguished: medial, dorsal, lateral rostral and lateral caudal. They differ in size and distribution density of neurons.
Subject(s)
Periaqueductal Gray/cytology , Animals , Cats , Cell CountABSTRACT
Stereotaxic microinjections of horseradish peroxidase (HP) were made into different parts of the rostral and caudal periaqueductal gray (PAG) in cats to study corticofugal projections to the PAG. The method of retrograde axonal transport of HP demonstrated labeled neurons in the I and II somatosensory areas, frontal, cingular and insular cortex of the brain. It was shown that the II somatosensory cortex projects to all the areas of the rostral and caudal PAG. The frontal cortex projects to the dorsolateral quadrant of the PAG. The findings obtained enabled the detection of the morphological substrate of the corticofugal effects on one of the antinociceptive brain structures--the PAG.
Subject(s)
Cerebral Cortex/anatomy & histology , Periaqueductal Gray/anatomy & histology , Animals , Axons/metabolism , Cats , Frontal Lobe/anatomy & histology , Horseradish Peroxidase/metabolism , Somatosensory Cortex/anatomy & histologyABSTRACT
On the basis of morphological investigations two areas were distinguished in the periaqueductal grey of the cat midbrain: medial, directly surrounding the sylvius aqueduct and containing small neurons with significant (P less than 0.001) prevalence of fusiform cells and lateral with larger neurons, where triangular cells were significantly (P less than 0.001) prevalent. The neurons of the medial area displayed a significant (P less than 0.001) tendency of their dendrite orientation towards the sylvius aqueduct.
Subject(s)
Periaqueductal Gray/cytology , Animals , Cats , Male , Neurons/cytologyABSTRACT
Descendin projections of the parafascicular complex (CM--Pf) of the cat thalamus to periaqueductal gray matter (PAG) of the midbrain were studied by Fink-Heimer electrocoagulation of CM--Pf complex in stereotaxic coordination. Degenerative changes in nerve fibers were most pronounced on transversal sections of the brain stem in the lateral nucleus of PAG, whereas less degeneration was seen in the ventral part of the medial nucleus.
Subject(s)
Mesencephalon/anatomy & histology , Thalamic Nuclei/anatomy & histology , Animals , Brain Mapping , Cats , Efferent Pathways/anatomy & histologyABSTRACT
To reveal the differences in the nucleus ventralis postero-lateralis (VPL) of the thalamus of the corticofugal fibers originating from the first (S1) and the second (S2) somatosensory areas a combined morphological study was undertaken using autoradiography and electron microscopy of the degenerating terminals. Within the range of VPL distribution of the cortico-fugal fibers of the corresponding zones of two cortical somatosensory regions differed from one another. The terminals of both types of the fibers established synaptic contacts, chiefly with the distal dendrites of the relay VPL cells, and much more rarely with the dendrites of the interneurons of the Golgi II type. No direct convergence of the fibers originating from two somatosensory regions on single VPL elements was observed.
Subject(s)
Somatosensory Cortex/anatomy & histology , Thalamic Nuclei/anatomy & histology , Animals , Autoradiography , Brain Mapping , Cats , Leucine/metabolism , Microscopy, Electron , Neural PathwaysABSTRACT
Results of morphological studies of degenerated fibers indicated that the first somatosensory area of the cortex was connected by the descending cortico-thalamic fibers with the posterior ventral nucleus of the thalamus. The second somatosensory area was simultaneously connected with the caudal portion of the posterior ventral nucleus and with the nuclei of the posterior group of the thalamus. The mentioned cortico-thalamic connections were distributed by the somatotopic principle.