CEREBRAL LOCALIZATION 703 



area, when the excitation of the corpus will evoke movements on that 

 side of the body which is still connected with the uninjured area. 

 Although generally associated with idiocy and epilepsy, certain cases 

 have been recorded by Wahler^ which show that lesions of the corpus 

 callosum in man give rise to a disturbance of the muscular movements. 

 Liepman^ describes cases in which dyspraxia existed without any ap- 

 parent injury to the motor cortex, the inference being that this 

 disorder resulted from defects in the power of conduction of the 

 corpus. 



THE BASAL GANGLIA 



The Corpus Striatum. — The nuclei caudati and nuclei lenticulares, 

 constituting the corpora striata, are intimately connected with the frontal 

 cortex by the corticocaudal bundle as well as with the thalamus, red 

 nucleus, and through the latter with the longitudinal bundle. They 

 form, therefore, important relay stations upon these paths and medi- 

 ate reflexes of the more complex kind. In the lowest vertebrates, 

 these bodies form almost the entire telencephalon and really serve as 

 the basal stem from which the hemispheres of the higher animals are. 

 developed. Their importance seems to be greatest in the birds, 

 because the more complex processes of these animals appear to be 

 mediated by these bodies, rather than by the palhum, or hemispheres. 



The question whether they possess an independent function, can- 

 not be answered with certainty, because their destruction by means 

 of injections of chromic acid, as well as their stimulation, has yielded 

 very conflicting results. Their close connection with the internal cap- 

 sule makes a direct involvement of these paths not improbable, and 

 hence, many of the effects described by earUer investigators^ may be 

 due to this cause. It seems to be established, however, that these 

 gangHa are closely associated with heat production and the regulation 

 of the body temperature,^ because their stimulation invariably results 

 in a rather lasting rise in temperature, amounting to as much as 1.6° C. 

 Mayer and Barbour have substantiated these results by permitting 

 warm and cool water to flow upon these bodies. CooUng the water 

 produced shivering and a rise in the body temperature, while warming 

 it lowered the body temperature. 



THE THALAMUS OPTICUS 



This body consists of three parts, known as the median, lateral, 

 and anterior nuclei. It is intimately connected with the corpus stria- 

 tum and the cerebral cortex by ingoing and outgoing fibers, and also 

 forms the end-station of the secondary sensory tracts of the spinal cord 



^ Balkentumoren, Leipzig, 1904. 



2 Med. Klinik, 1907, 725. 



3 Schuller, Zentralbl. ftir Physiol., 1902, 222. 



^ Jto., Archiv fiir Physiol., 1898, 537, and Zeitschr. fur Biologie, xxxciii, 1898, 36; 

 also Nicolaides and Dontas, Archiv fiir Physiol, 1911, 249. 



