NERVE 



115 



stimulation may be associated with crude modification of 

 consciousness. 



As will be seen later there is good evidence 

 that stimulation of the thalamus may lead to muscular 

 movements without implication of the cortex through the 

 corpus striatum and red nucleus (p. 189). 



3. Synapses in the Cortex Cerebri. — From the nuclei of the 

 thalamus fibres, which early get their white sheath, extend 



-^ X 



FRONTAL 

 MOTOR- 



SENSORY- 



ECTOSYLVIAN 



TOSYLVIAN 6... 



Parietal 



VISUAL 



S OrVttiUs.. 



, -S Cruc.i.a.t\iS. 



SCorona-lis. 

 H omologuC 

 oj RolliuLo 



Rkir 



- SSu.pri.s^lviuS 



S Literalii. 



Sfttoliteralis. 



CiXcinne-' 



SPoiUiteiilis. 



Post-ca.TcaT(.r\e 



TUSfRCULUM OLFACT. 



^..OLFACTORY. A.. 



l^ti'- :lfact 



ORY B 



0^..fXTRA-RHINie. 



VISUAL" 



Fio. 52. — Superior and inferior aspectsof the brain of the dog to show the various 

 sulci and the distribution of the chief receiving and reacting mechanisms. 



outwards to that part of the cortex cerebri which lies 

 round the central fissure (figs, 50 and 53). That this part 

 of the cortex is closely associated with the changes in 

 consciousness has been proved both by studying the effects of 

 (a) stimulation, and of (6) removal, and (c) by careful observa- 

 tion of the symptoms following disease or injury. 



Mott found that, when the cortex round the central 

 fissure on one side of the brain of a monkey is removed, 

 clips may be attached to the skin on the opposite side of the 

 body without attracting attention, while if they are placed 

 on the same side they are at once removed. He therefore 

 regards this region of the brain as connected with the 

 reception of tactile impressions. 



These conclusions have been supported and amplified by ex- 

 perimental observations during operations on the human brain. 



