92 Dr. H. C. Bastian. On the Relations of Sensory [May 2, 



From the point of view of sensory guidance, cortically initiated 

 movements are divisible into two categories : (I) Speech movements, 

 which are now known to be produced under the guidance of co-active 

 auditory and kintesthetic centres ; and (II) Limb and other bodily 

 movements, which are equally well known to be produced under the 

 guidance of co-active visual and kinsesthetic centres. In each case 

 the kinaesthetic centres do not seem to act independently, but only in 

 response to the primarily initiated activity in the auditory or in the 

 visual centres respectively these latter in all cases seeming to take 

 the lead. 



I. Speech Movements. Words appear to be revived in thought, in 

 the main, in the auditory centres, and, if they are to be spoken, 

 stimuli from these centres must pass along associational fibres to 

 related portions of the kinsesthetic centre, that is, to what I have 

 termed the " glosso-kinaesthetic " centre, in and near the posterior 

 part of the third frontal convolution. If we assume, as clinico- 

 pathological evidence seems to warrant, that the portion of the 

 auditory centre concerned with the registration of the sounds of 

 words is situated in the posterior part of the upper temporal con- 

 volution, the associational fibres in question would pass in their 

 course from the auditory centre beneath the Island of Reil in order 

 to reach the glosso-kinsesthetic centre. From this region the com- 

 bined stimuli would pass off from the cortex (and through, the 

 internal capsule), so as to evoke in appropriate ways the activity of 

 the proper motor centres for speech situated in the bulb (fig. 1). 



It has now been ascertained that speech movements may be 

 paralysed by lesions in any part of this tract from the auditory centre 

 to the bulb. Lesions in either of the two sensory centres will pro- 



FIG. 1. Diagram illustrating relative Positions of three Cerebral Centres concerned 



with Speech. 



GJLC. 



A.C. 



AC, auditory centre ; GKC, glosso-kinsesthetic centre ; BMC, bulbar motor 

 centre ; x, audito-kinsesthetic commissural fibres; y, internuncial fibres. 



