The evolution of our knowledge of the brain during the last sixty years : illustrated with a series of personal observations / Charles K. Mills, M.D. Philadelphia, Pa.
- Charles Karsner Mills
- Date:
- [1927]
Licence: In copyright
Credit: The evolution of our knowledge of the brain during the last sixty years : illustrated with a series of personal observations / Charles K. Mills, M.D. Philadelphia, Pa. Source: Wellcome Collection.
6/20 page 4
![My personal views on inhibition differ somewhat from those usually held. It is well known to all that, in cases of incomplete transverse lesion of the spinal cord, reflexes in the parts supplied below the lesion are exaggerated, sometimes grossly so, as evidenced by such phenomena as patellar clonus, ankle clonus and the toe reflexes of Sinkler (The Toe Reflex, Med. Ncivs 53:611 [Dec. 1] 1888), and other defensive reflexes. Usually these cases are explained on the theory of withdrawal of cerebral inhibition, but I doubt the correctness of this explanation. In a paper presented to the Philadelphia County Medical Society, in 1915 (Penn. M. J. 18 :496 [March] 1915), I cited Bastian’s (Medico Chirurgical Trans. 73:151, 1890) well known case of complete transverse lesion of the cervical cord, and referred to another case of my own of equally complete transverse lesion of the thoracic cord. Certainly all cerebral inhibition must have been withdrawn in these cases; yet in both cases and in others which I have studied, there was com¬ plete atonic paralysis with lost reflexes in the lower limbs. My view is that there is a special peripherospinal and cerebral tonectic apparatus (Neurol. Centralbl. 33:1266 [Dec. 16] 1914). Sensory stimuli maintain a standard tonectic state in the normal person or a uniform condition of tonic innervation. When the corticotonectic stimuli are rhythmically delivered, they maintain the motor system in the state of normal muscle tonicity. Complete withdrawal may occur either through lesion of the sensory pathway or through more or less com¬ plete lesion of the pyramidal tract. If there is a partial block, the result is an overcharge of tonic innervation. The hypertonia is expended in a forcible and irregular way on the lower spinal neurons and gives rise to the resulting hyper¬ tonicity and increased reflexes. It is at least doubtful whether the Nissl second type of small cells is set aside for inhibition. My own studies, of the cerebral cortex, of the striatum and of the cerebellar deep nuclei, point to these small cells as associating in function. In fact, to me it does not seem necessary to assume two types of cells, one for excita¬ tion and one for inhibition. The large motor cell types may exert inhibitory influ¬ ence in particular cases, as can be shown by numerous examples. Inhibition is a function of much importance in the central nervous system, but it does not follow that it requires a distinct type of cells for its performance, as. in the vegetative system. In 1917, a paper by Dr. George Riddoch (Brain 40:265 [Nov.] 1917) appeared on “The Reflex Functions of the Completely Divided Spinal Cord in Man, Com¬ pared with Those Associated with Less Severe Lesions.” In 1920, a paper by Head and Riddoch also appeared (Studies in Neurology, London, Oxford Univer¬ sity Press, vol. 2, 1920, p. 467). The work by Riddoch was conducted largely under the direction of Head. Both of these articles have great significance in connection with the discussion of inhibition. Riddoch’s paper at first seemed to oppose Bastian’s views, founded on his cases of complete division' of the spinal cord in the cervical region, and also my views founded on cases of cervical and of thoracic complete transection. Careful reading of the paper, especially of the cases reported by Riddoch, indicates that Riddoch’s observations and conclusions are not entirely opposed to those of Dr. Bastian and myself. The question of the origin of cerebral tone must first be borne in mind. Tone, like every other function in the human nervous system, has its origin in the outside or inside periphery. Impressions or stimuli in the periphery outside the body are received by exteroceptors, namely cutaneous and mucous membrane receptors. Impressions or stimuli from within the body—from muscles, joints, bones and](https://iiif.wellcomecollection.org/image/b30801199_0006.jp2/full/800%2C/0/default.jpg)
