. The brain as an organ of mind. the head andeyes, with elevation of theeyelids and dilatation ofthe pupil (attitude ofatten-tion )—in posterior partsof upper and middle frontalconvolutions. {a, h, c, d.) Centres formovements of the hand andwrist — in the ascendingparietal convolution. The relative position of showing the relative positions of some of the -^^jese supposed motor cen-so-called Motor Centres/ in the left Cei^bral , . ^ ,^ ^^ ^^^^ ^f ^^^^ Hemisphere. (Ferrier.) For references see Text, ^^^^ ^ and also Fig. 172. most import ant allegedsen- sory centres is also shownin Fig. 182, in
. The brain as an organ of mind. the head andeyes, with elevation of theeyelids and dilatation ofthe pupil (attitude ofatten-tion )—in posterior partsof upper and middle frontalconvolutions. {a, h, c, d.) Centres formovements of the hand andwrist — in the ascendingparietal convolution. The relative position of showing the relative positions of some of the -^^jese supposed motor cen-so-called Motor Centres/ in the left Cei^bral , . ^ ,^ ^^ ^^^^ ^f ^^^^ Hemisphere. (Ferrier.) For references see Text, ^^^^ ^ and also Fig. 172. most import ant allegedsen- sory centres is also shownin Fig. 182, in which the circles 13 and 13 indicate what is regarded•by Ferrier as the Visual Centre {in the supra-marginal lohule andthe angular gyrus), whilst the circles 14, 14 indicate the situationof the Auditory Centre {in the upper temporal convolution). Thecentres of Touch, Smell, and Taste are, as we have previouslyinontioned (pp. 53r,-r)40), believed to be located in convolutions onthe inner aspect and tip of the Temporal Fig. 183.—Upper aspect of Monkeys Brain, Chap. XXVI.] VOLUNTARY MOVEMENTS. 575 As an example of the kind of evidence upon whichthe above-mentioned localizations in regard to SpecialMovements have been made, one of Ferriers experimentalobservations bearing upon this point may be quoted. The left hemisphere of a monkey was exposed in the regionof the ascending frontal convolution sufficiently to display thecentre of bicipital action [fig. 182, 6j or supination and flexion ofthe forearm. The exact spot being determined by the applicationof the electrodes, it was then accurately cauterised, just sufficientlyto destroy the cortical grey matter. This operation immediatelymanifested itself in paralysis of the power of flexing the right fore-arm. All the other movements of the limbs were retained, butwhen the right arm was placed in an extended position the animalwas utterly powerless to flex it, and the limb hung in a state of flaccid extension when the ani
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