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A MANUAL OF PHYSIOLOGY 



per 

 AF 



occipito-temporal external, they end in the grey matter of the 

 pons, and serve as one segment of an extensive commissural 

 connection between the cerebral and the cerebellar cortex of 

 the opposite side, the other segment being formed by neurons 

 whose cell-bodies are situated in the pons, and whose axons, 



crossing the middle line, 

 pursue their course 

 through the middle cere- 

 bellar peduncle, to termi- 

 nate in the superficial grey 

 matter of the cerebellum. 

 It is evident that the junc- 

 tion of the cerebral cortex 

 with this pontine grey 

 matter, through and into 

 which so many nerve- 

 tracts pass, multiplies the 

 number of possible routes 

 by which impulses may 

 travel between one part 

 of the brain and another. 

 The corpus callosum forms 

 a mighty link between the 

 two cerebral hemispheres. 

 And intertwined in the 

 corona radiata with the 

 c^Jlosal fibres are other 



Fr, frontal ; Oc, occipital lobe ; the in- Systems, of which it is CS- 

 terrupted lines indicate the fibres (TOC) con- pecially necessary to men- 

 necting the cerebellum and the temporo- 

 occipital cortex, and the fronto -cerebellar 

 fibres (FC). On the left side the position 



if".. 335- FIBRES CONNECTING FRONTAL 

 AND TEMPORO - OCCIPITAL LOBES WITH 

 CEREBELLUM, ETC. (DIAGRAM) (AFTER 

 GOWERS). 



tion the afferent (corti- 

 petal) fibres that join the 



of these two groups of fibres and of the motor optic thalaniUS With nearly 



every part of the cerebral 



(pyramidal) tract, PY, in the crus, is indi- 

 cated by letters. The pyramidal tract is o t, in- 

 seen on the right passing down from the cort ex. bUCh fibres pass 

 Rolandic area through the posterior limb of from the Cells of the grey 

 the internal capsule 1C (the genu or knee of matter of the thalaniUS to 

 which is indicated by the asterisk) to de- ,v , i , -, 

 cussate in the bulb. AF, ascending frontal the f ntal and parietal 

 convolution; AP, ascending parietal con- regions through the an- 

 volution ; FR, fissure of Rolando ; IFF, in- 

 traparietal fissure ; PCF, precentral fissure ; 

 Ipt, crossed pyramidal tract ; apt, direct 

 pyramidal tract. 



terior border of the in- 

 ternal capsule in front of 

 the frontal fibres pre- 

 viously described as run- 

 ning in the anterior limb of the capsule to the pons ; and from 

 the thalamus to the occipital region through the extreme pos- 

 terior border of the internal capsule, behind the occipital fibres 

 that proceed to the pons. The fibres that connect the thalamus 



