The spinal cord, at least in higher animals, almost exclusively plays the rôle of a conductor with regard to sensation. The thalamus and the cerebral cortex are the essential integrating sensory mechanisms, and it is with these two mechanisms that I shall deal.
Knowledge of the functions of the thalamus began in the middle of the nineteenth century with Luys, Todd and Carpenter, who conceived of the thalamus as the subcortical center to which the sensory pathways and impulses converge. This was established anatomically by von Monakow, and it is generally accepted today. I think that all the various impulses, segregated in the spinal cord, finally reunite in the thalamus. There the final, thalamocortical neurons begin, which end in the somatic sensory cortex.
Modern neurology of the thalamus dates from the clinical investigations of Dejerine, Long and Roussy and the experimental work of Roussy. These investigations established that destruction of