411 
1910-11.] Topography of Cerebral Cortex of Guinea-pig. 
was, however, found impossible to mark off different centres for the various 
movements. In practically all the experiments performed it was found 
that a stronger current was required to cause movements of the hind limbs 
as contrasted with the fore limbs. Movements of the eyelids were generally 
most easily elicited, but twitching movements of the nose and face were 
frequently well marked and elicited with almost equal ease. 
The accompanying diagram (fig. 9) shows the position and approximate 
extent of the motor area, while the letters correspond to the position where 
certain movements were most frequently elicited. 
Fig. 9. — Upper surface of cerebrum, showing the excitable area 
(marked by dotted line) as determined by electrical stimulation. 
1. Sylvian fissure. 2. Lateral fissure. 
A. Movements of the hind and fore limbs were elicited by stimulation 
of this part of the cortex, an increase of current being necessary to 
cause hind limb movements. 
B and B'. This represents the cortical area over which stimulation was 
found to cause fore limb movements. B represents the area 
which gave an active reaction, B' the area associated with a 
comparatively weak reaction. 
C. Over this area stimulation is associated with movements of the 
eyelid. This is probably one of the most definite areas, as the 
movements are very easily elicited. 
D. Movements of the nostrils, and occasionally twitching of the facial 
muscles, were produced in some of the experiments by stimulation 
of this area. 
E. A twisting movement of the neck was in some cases associated with 
stimulation of this area. 
