On the localisation of movements in the brain / by J. Hughlings Jackson.
- Jackson, John Hughlings, 1834-1911.
- Date:
- [1875]
Licence: Public Domain Mark
Credit: On the localisation of movements in the brain / by J. Hughlings Jackson. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![xxxrr tactual, the perception of every statical attribute of body [shape, size] is resolvable into perceptions of relative posi- tion which are gained through motion.33 Again, Vol. 2, op. cit., p. 171. “Those motions of the eye required to bring the sentient elements of the retina successively in contact with different parts of the image, being themselves known to consciousness, become components of the perception.33 Again, p. 172, that “ the primitive element out of which our ideas of visible extension are evolved, is a cognition of the relative positions of two states of consciousness in some series of such states, consequent upon a subjective motion” If we acquire ideas of the primary or statical qualities of bodies by movements—if, when we “ really” see an object, movement is essential—must there not be an element of movement represented in those anatomical substrata during excitation or discharge of which we see the object “ideally?”* For when we “ think” of the object which is absent (“ recollect” it, “ are conscious” of it, See.) we necessarily see it ideally of some shape, as well as of some colour. The inference is irresistible that there must be a motor, as well as a sensory, element in the nervous arrangement in the “ organ of mind” which is faintly discharged when we “ think of” an objeet. This notion is to many unfamiliar. It seems unlikely to be true, but apparently only because it is novel. “ What can movement have to do with ideas ? One is * I beg the reader to observe that this is not an after-thought. I do not write this because Hitzig and Ferrier find that they develope movements of the eyes by electrical excitation of certain parts of the cerebral cortex. I believed that move- ments of the eyes must be represented in the cerebral hemispheres before their experiments were begun. Before it was surmised that movements could be produced by artificial excitation of the brains of healthy animals, I wrote as follows (Medical Times and Gazette, October 23, 1869) of the anatomical substrata of visual ideas :—“ In the organised forms which serve as the mental representatives of objects when the objects are absent, there will therefore be comprised not only impressions of surface, but residua of movements . . . The speculation supposes that we have particular visual impressions in fixed association with particular ocular movements.” A convulsion in which the eyes are strongly deviated is owing to an excessive discharge of a part where the motor elements of the substrata of visual ideas are largely represented.](https://iiif.wellcomecollection.org/image/b22355078_0038.jp2/full/800%2C/0/default.jpg)
