Cortical lamination and localisation in the brain of the marmoset / by F.W. Mott, E. Schuster and W.D. Halliburton.

  • Mott, F. W. (Frederick Walker), 1853-1926.
Date:
[1909]
Catalogue details

Licence: In copyright

Credit: Cortical lamination and localisation in the brain of the marmoset / by F.W. Mott, E. Schuster and W.D. Halliburton. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    of the cortex lying immediately round the corpus callosum, from its anterior to its posterior genu. Sections cut through the hippocampal fissure show a narrow strip of cortex having the same structure bordering the olfactory type, lying between it and the distinctive structures of the hippocampal fissure. It is probable that, as in the Lemur, a narrow strip of limbic cortex is to be found curving around the posterior genu of the corpus callosum, and folding in to the hippocampal fissure, thus forming a link between the upper and lower portions of the limbic lobe. Characteristics.—The cortex measures 08 mm. to l-0 mm., the depth of the molecular layer being about 0-2 mm. The remainder of the cortex cannot be separated into layers. The cells immediately beneath the molecular layer have a tendency to be pyramidal in form, but below these the mass of them are blunt, shapeless, and faintly stained, only becoming more angular at the bottom of the cortex, in the position of the polymorph layer. Localisation of the Motor Area by Stimulation. The animals were anaesthetised either by ether or A.C.E. mixture, and anaesthesia was maintained throughout the whole of the operation until the animals were killed at the conclusion of the experiment. In dealing with so small a brain, the parts are so delicate that the greatest possible care has to be exercised throughout. In one experiment the animal died from haemorrhage owing to the injury of a vessel entering the longitudinal sinus, in an attempt to separate one hemisphere from its fellow in order to stimulate the mesial surface, and further attempts to explore this portion of the cerebrum were therefore abandoned. In the remaining two experiments, in which the greater part of the external surface of the hemisphere was exposed, we obtained concordant results by the method of stimulation. The stimulating electrodes were finely pointed and very close together; they were made of platinum and were connected to the secondary coil of a Du Bois Beymond inductorium arranged for faradisation. The strength of current employed was that which could just be felt as a faint tingling on the tongue. The accompanying illustration (fig. 7) gives the results of these experiments. It represents the left hemi- sphere seen partly from the side and partly from above, to show the excitable area. This will be seen to be situated wholly above and in front of the Sylvian fissure. If the various figures placed on the diagram are compared with the description beneath it, it will be seen that the head area is a large one, and above this are situated the centres for the upper limb and then those for the lower limb, which is the usual arrangement. The larger cortical representation of the head and face region enabled one