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VI. A Minute Analysis (Experimental) of the Various Movements produced by 
stimulating in the Monkey different Regions of the Cortical Centre for the Upper 
Limb, as defined by Professor F errier. 
By Charles E. Beevor, M.D., M.R.C.P., and Victor Horsley, B.S., F.R.C.S., 
F.R.S., Brown Professor of Pathology at University College, London. 
Received Jane 4,—Read Jane 10, 1886. 
[Plate 7.] 
The following research was undertaken as a necessary preface to an investigation, 
which we are at present engaged upon, into the localisation of motor function in the 
cervical enlargement of the spinal cord. 
Briefly speaking, the experiments from which the following conclusions have been 
drawn consisted in an elaborate examination of the movements elicited by stimulating 
with the interrupted induced current every part of the motor cortex in the Monkey, 
in which the upper limb is primarily represented, as first described by Professor 
F errier. 
Before entering, however, on a detailed description of the present research, it will be 
necessary to discuss shortly the anatomical features of the parts of the cortex 
concerned, 
Anatomy. —A glance at the accompanying diagram of the external or convex surface 
of the left cerebral hemisphere of the Macacque Monkey shows that Ferrier’s motor 
region is bounded interiorly by the fissure of Sylvius, posteriorly by the intra-parietal 
sulcus, superiorly by the margin of the hemisphere, and anteriorly by a narrow strip 
of grey matter* in front of the vertical limb of the prsecentral sulcus, and also by 
that sulcus itself. The central point of this area is the middle third of the ascending 
frontal convolution, and in this portion of the cortex and around it we have the 
cortical “ centre ” for the movements of the opposite upper limb. 
Before enumerating the functions of this portion of the cortex it is incumbent upon 
us to draw attention to certain minute characteristics of the various sulci of this 
region, these being of great constancy, and therefore of primary importance in aiding 
exact localisation of function. 
* By this is meant portions of the bases of the frontal convolutions, the extent of which can be 
mapped out by electrical excitation. 
MDCCCLXXXVII. —B. 
X 
23.11.87 
