THE CEREBELLUM 



■275 



Mechanisms of Cumpensatum 



It was indicated earlier that Luciani (188-190) 

 expressed his opinion tliat compensation for cerebellar 

 deficiencies occurred by virtue of the acquisition of 

 new functions by structures not previously inxolved 

 (organic compensation) and through a process of 

 learning and trainins; which permitted correction of 

 deficits (functional compensation). In terms of the 

 mechanisms in\olvcd in these different forms of com- 

 pensation (if indeed they be different), we know no 

 more than we know about learning and the acquisi- 

 tion of skill in general. Nevertheless, the location of 

 structures involved in the compensation processes 

 has, to a limited degree, been revealed. 



It has been repeatedly emphasized (36, 188-190) 

 that if additional cerebellar lesions are made in an 

 animal already compensated, the resulting new deficits 

 exceed in intensity those which would have occurred 

 as a result of the second lesion alone. It would thus 

 appear that the cerebellum itself is involved in the 

 changes occurring during compensation. The role of 

 spinal cord inhibition in the recovery from the dy- 

 namic signs and in the precipitation of atonia has 

 already been alluded to (12, 16). The original observa- 

 tions by Luciani (188-190) of the reappearance of 

 deficiency signs in a compensated animal following 

 removal of the cerebral motor cortex have been re- 

 peatedly confirmed. Thus, the cerebral cortex must 



also be involved in the reorganization of the control 

 system which brings about compensation. In addi- 

 tion, it has been demonstrated in the cat tliat com- 

 pensation from unilateral fastigial lesions occurs in 

 14 to 35 days; that compensation following subsequent 

 bilateral motor cortex ablation occurs in 14 to i 7 days; 

 and that the compensation following decortication 

 is premesencephalic in its location (12, 16). 



CEREBELL.^R DEFICIENCIES IN .V1.-\N 



The emphasis in this chapter has been upon the 

 discussion of cerebellar functions as they are revealed 

 by observations upon experimental animals under 

 conditions that permit an attempt at an experimental 

 analysis. Fundamentally, the signs of cerebellar de- 

 ficiency in man are like those seen in experimental 

 primates (126) with a more grave disturbance of 

 skilled movement and a more profound and enduring 

 hypotonia. No attempt will be made to describe the 

 cerebellar syndrome in man, the reader being referred 

 to the excellent discussions of Holmes (158, 159), 

 Goldstein (133), Bremer (36) and Moruzzi & Dow 

 (241). It should be remembered that a) in man cere- 

 bellar disease or injury rarely respects anatomical 

 boundaries and h) the signs of slowly developing 

 cerebellar lesions are mitigated and sometimes ob- 

 scured by concurrent compensation. 



REFERENCES 



1. Adrian, E. D. J. Physiol. 83: 32, 1935. 



2. Adrian, E. D. Brain 66: 289, 1943. 



3. Albe-Fessard, D. and T. Szabo. J. physwl., Paris 46: 

 225. 1954- 



4. Albe-Fessard, D. and T. Szabo. Compl. rend. .Snc. de hiol. 

 149: 1090, 1955. 



5. Arduini, .■\., A. BoR.^zo and A. Brusa. Boll. Soc. ilnl. 

 biol. sper. 31 : 815, 1955. 



6. Arduini, A. and G. C. Lairy-Bounes. Eleclronicephalog. 

 & Clin. Neuropkysiol . 4: 503, 1952. 



7. Ardwni, A. , G. Moruzzi and C. Terzuolo. Arcli. fisiol. 

 50: 328, 1951. 



8. Arduini, A. and O. Pompeiano. Boll. .Soc. ilal. biol. .sper. 

 32:947. 1956- 



9. Aring, C. D. and J. F. Fulton. A.ALA. Arch. .Xeurol. & 

 Psychial. 35: 439, 1936. 



10. Bach, L. M. N. and H. VV. Magoun. J. .Veurophvsiol. 10: 

 331. >947- 



11. Bard, P., C. N. Woolsev, R. S. Snider, V. B. Mount- 

 castle and R. B. Bromiley. Fed. Proc. 6: 72, 1947. 



12. Batini, C, G. Moruzzi .\nd O. Pompeiano. Arch. ilal. 

 biol. 95: 71, 1957. 



13. Batini, C. and (). Pompeiano. Boll. Soc. ilal. hud. sper 

 31:805, 1955. 



14. Batini, C. and O. Pompeiano. Boll. Soc. ital. hiol. .iper. 31 : 

 1223, 1955. 



15. Batini, C. and O. Pompeiano. Atli accad. na.-J. Lincei, 

 Rend. Classe sci. fis. mat. e nat. 20 : 504, 1 956. 



16. Batini, C. and O. Pompeiano. Arch. ilal. biol. 95: 147, 



'957- 



1 7. Batini, C. and O. Pompeiano. A'.V Internal. Physiol. Congr., 

 Abstr. of Cormnunic. 71, 1956. 



18. Batini, C. and O. Pompei.\no. Arch. ilal. biol. In press. 



19. Beck, A. and G. Bikeles. Arch. ges. Physiol. 143: 283, 1912. 



20. Beck, .\. and G. Bikeles. Arch. ges. Physiol. 143: 296, 

 1912. 



21. Beritashvili, I. and L. Tzkipuridse. Bull. Georg. Acad. 

 Sc. USSR V, VI, 1945. Cited by von Buddenbrock (351). 



22. Beritoff, J. S. and R. Magnus. Arch. ges. Physiol. 159: 

 249, 191 4. 



23. Bernis, W. J. and E. a. Spiegel. Arb. Neurol. Inst. IVien 



27: '97. 1923- 



24. Bickers, D. S., E. W. Peterson and J. Scherrer. Am. jf. 

 Physiol. 159: 562, 1949. 



25. BiNG, R. Arch. Anal. u. Physiol., Physiol. Abl.: 250, 1906. 



