Showing papers on "Motor neuron published in 1968"

Proximal axonal enlargement in motor neuron disease.

Abstract: THE PURPOSE OF TMS PAPER is to draw attention to a histological phenomenon which may be seen in certain cases of motor neuron disease, namely focal enlargement of axons of cells in the anterior horns of the spinal cord and in the somatic motor nuclei of the brainstem. Correlation between the clinical course of the disease and the presence of these axonal changes seems possible. The mechanism of their production is unknown, although some relevant data are available. The size and shape of the axonal enlargements may be such that they can be mistaken for chromatolytic neurons. This is perhaps the reason why they are seldom mentioned in pathological descriptions of the disease, although in 1957 Wohlfartl stated that argyrophilic axonal bodies were an invariable, though nonspecific, finding in motor neuron disease. He saw them in the ventral horns, the brainstem, and, to a lesser extent, the cerebral cortex. They were from 2 to 30 p in diameter. He felt that most of them represented terminal knobs of axons but that a few were separated from their parent axon. He envisaged 3 possibilities for their genesis: [l] that they were formed from collateral outgrowth from damaged axons of ventral horn cells, [2] that they were formed from axons having previous synaptic contact with now defunct ventral horn cells, or [3] that they were formed from dying back of terminal axons of corticospinal fibers entering the anterior horns. He noted that axonal enlargements were most numerous at the ventral side of the ventral horns but that they were seen fairly often close to neuronal perikarya. Hirano and associates2 have described swollen neuronal processes which were larger than neurons in a case of familial amyotrophic lateral sclerosis from the United States. Cytoplasmic inclusions, often multiple, were seen within the anterior horn cells. These inclusions sometimes appeared to distend the axons. The duration of the disease was nine months.

Fiber‐analytical studies on the pyramidal tracts in cerebrovascular and motor neuron diseases

Abstract: Since Haggqviste) and Lassekll) paid attention to the fiber distribution of the pyramidal tract in 1930's, the human pyramidal tract has been one of the main subjects of study for many morphologists and physiologists. Particularly for the morphological investigation, the medullary pyramid was mostly studied because of its easy accessibility and its well-confined localization. In 1940, Lassek and Rasmussenlz) examined the human pyramidal tract with silver stain and found that the predominant type of axiscylinder was one of small caliber. Lassekls), in 1942, first performed the fiber-analytical study on the normal human medullary pyramid with myelin sheath stain and reported that about 90 per cent of the myelinated fibers in the human pyramidal tract ranged between 1 and 4 microns(p) in diameter. In order to investigate the origin of these fibers passing through the medullary pyramid, numerous works have been done mainly based on animal experiments. As far as the human cases are concerned, the study on the pathological materials in comparison with normal controls contributes greatly to the elucidation of the clinico-morphological problem of the pyramidal tract. Haggqviste) in 1936, Verhaart26) in 1948, and Brownl) in 1961, respectively, analyzed the fiber components of the corticospinal tracts in the human cases with hemiplegia and found mostly the large fibers degenerated or lost. Hirayama et a1.9), in 1962, studied the fiber distribution of the internal capsule in three cases with amyotrophic lateral sclerosis with myelin sheath stain of paraffin sections, and found few fibers of caliber larger than 8 p left in the tract. The role played by these large fibers and the origin of the pyramidal tract fibers have been the matter of controversy for long's). However, as there have been very few works concerning the human pyramidal tract based on complete fiberanalytical studies, the present investigation was tried. The purpose of this paper is to report the fiber-analytical study mainly of the corticospinal tracts in the human cases with upper motor neuron involvement, and to discuss about the relation between the fiber degeneration in the tract and the clinical manifestation of the motor paresis.