Lesions of the central and peripheral nervous systems produced in young rabbits by vitamin A deficiency and a high cereal intake / by Edward Mellanby.

  • Mellanby, Edward, Sir, 1884-1955.
Date:
[1935?]
Catalogue details

Licence: In copyright

Credit: Lesions of the central and peripheral nervous systems produced in young rabbits by vitamin A deficiency and a high cereal intake / by Edward Mellanby. Source: Wellcome Collection.

    18/48 (page 158)
    evidence of degeneration in a third neuron has been found either in this rabbit or in any others of the series so far examined. Medulla, lower part of sensory decussation (rabbit B) (fig. 14).—Ascending degeneration is seen in the fillet, in the ventral spino-reticulo-thalamic tract, in the dorsal and ventral spino-cerebellar tracts, in the lateral spino-reticulo- thalamic, in the spino-tectal and possibly the spino-olivary tracts. Descending fibres in the dorsal longitudinal bundle, the vestibulo-spinal and the rubro¬ spinal tracts are degenerated. At this level the dorsal longitudinal bundle and the vestibulo-spinal tract can be seen in separate bundles, while in the cord they could not be clearly differentiated from other tracts. Medulla, level of the inferior olivary nucleus (below ith ventricle) (rabbit B) (fig. 15).—In this section there is much degeneration in the fillet and also some in the dorsal spino-cerebellar tracts, but less than in rabbit A. The ventral spino-cerebellar, spino-reticulo-thalamic and spino-tectal tracts contain some degenerated fibres which are seen in the same positions as in fig. 8. Degenerated fibres of the vestibulo-spinal tract appear dorsal to the inferior olivary body. The dorsal longitudinal bundle and the rubro-spinal tracts containing degenerated fibres retain the same relative positions. There is no degeneration in the pyramids. So far, degeneration has not been found in the 12th, 11th, 10th or 9th nerves. Medulla, level of inferior olivary nuclei and 4:th ventricle (rabbit B) (fig. 16). Degenerated fibres of the mesial fillet are the most prominent features of this section, degeneration being heavier than in any other of the ascending tracts. The dorsal spino-cerebellar, ventral spino-cerebellar, spino- reticulo-thalamic and spino-tectal tracts contain some degenerated fibres. The dorsal longitudinal bundle and vestibulo-spinal tracts are the most severely degenerated of the descending fibres, but the descending vestibular root and the rubro-spinal tracts are also affected. In contrast to fig. 9 (rabbit A) there are no degenerated fibres among the cells of the lateral reticular nucleus. The pyramids are again without degenerated fibres. Level of 8th nerve (rabbit B) (fig. 17).—This section shows degenerated ascending fibres in the fillet, restiform body, spino-reticulo-thalamic, ventral spino-cerebellar and spino-tectal tracts. Degenerated descending fibres are seen in the dorsal longitudinal bundle, vestibulo-spinal and rubro-spinal tracts. The pyramids are again unaffected. Boots of the 8th and 7th nerves can be seen and many degenerated fibres are present in the former, but none in the latter. Lons, 5th nerve level (rabbit B) (fig. 18).—Degeneration can be seen in the regions of the spino-reticulo-thalamic and spino-tectal tracts. The degenerated fibres of the restiform body have disappeared, and the degenerated ventral spino-cerebellar tract is now coursing towards the superior cerebellar peduncle. Degenerated fibres can be seen in the dorsal longitudinal bundle and what are presumably the rubro-spinal and vestibulo-mesencephalic tracts. The pyramids are again free from degeneration. Degeneration can be clearly seen in the fibres of the 5th nerve.