710 



HANDBOOK OF PHYSIOLOGY 



NEUROPHYSIOLOGY I 



impossible to elicit the ccntriiugal spike by light. It 

 is at the moment too early to put forth a theory of 

 the role of centrifugal control. 



ERG OF M.^N: its CLINICAL USE 



erg's of man have been recorded from the very 

 earliest time of electroretinography but the first really 

 good records were published by Hartline (85). The 

 work gradually got under way, particularly when 

 the first more differentiated responses separating 

 rods and cones were published by Motokawa & 

 Mita (no) and Adrian (i, 2) and when Karpe (96) 

 started clinical electroretinography. In 1956 this 

 subject gathered a large number of European con- 

 tinental and British students of the human ERG to a 

 first symposium in Hamburg (128). The contriljutions 

 to this symposium provide a convenient introduction 

 to the literature of electroretinography, particularly 

 in its clinical aspects. 



Since in man it is impossible to open the eye and 

 use microillumination of selected spots and, at the 

 same dme, the dominant phase of the human ERG 

 is a rod response requiring dark-adaptation, the 

 question of whether the ERG is a generalized re- 

 sponse to stray light or is focally elicited has created 

 considerable interest. Contributions to this discus- 

 sion by Fry & Hartley (57), Boynton & Riggs (27), 

 Asher (13), Boynton (26), Wirth & Zetterstrom 

 (150), Marg & Heath (106) and Brindley (29) should 



be consulted. There is general agreement that stray 

 light is unavoidable at the strength needed for an 

 ERG to be recorded in the human eye, i.e. from the 

 cornea; in particular, clinical work shows that evi- 

 dence of large scotomata may fail to appear in the 

 ERG (96). In cats, as stated, an area of 20 mm- 

 must be illuminated for a maximum ERG (150). 

 With regard to localized focal stimuli in opened eyes 

 of animals and whether they can interact or not, 

 opinions still differ (29, 106). 



Much recent theoretical work on the human ERG 

 has been devoted to the identification of its various 

 deflections and components, particularly with regard 

 to rods and cones (12, 14, 21, 40, 41, 48, 130, 148), 

 and to a study of its sensitivity to colored lights (as 

 mentioned above). 



The clinical values are both diagnostic and prog- 

 nostic. Karpe (96) initiated the work iiy bringing 

 together the data necessary for establishment of 

 normal standard values for the b-wave and for de- 

 fining a number of fundamental pathological types 

 of initial deflections. There has since been much 

 systematic work done, and in many eye hospitals 

 recording of the ERG is a routine procedure, not 

 only when the eye media are opaque but also for 

 the prognosis of varieties of tapetoretinal degenera- 

 tions, to decide whether treatment should be surgi- 

 cal or not, in children (151), etc. It seems that early 

 changes in the ERG or failure of such changes when 

 the ophthalmoscopic picture suggests a pathological 

 retina are of considerable prognostic value. 



REFERENCES 



D. AND R. M.ATTHEWS. J. Ffiystol. 64: 279. 

 D. AND R. Matthews. J. Physiol. 65; 273 



1. Adrian, E. D. J. Physiol. 104: 84, 1945. 



2. Adrian, E. D. J. Physiol. 105; 24, 1946. 



3. Adrian, E. D. and R. Matthews. J. Physiol. 63: 378 

 1927. 



4. Adrian 

 1927. 



5. Adrian 

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6. Andree, G. and H.-VV. Mui.i.er-Limmroth. J^lschr. Biol 

 106: 395, 1954. 



7. Arden, G. B. and D. p. Greaves. J. Physiol. 133; 266 



8. Arden, G. B. and K. Tanslev. J. Physiol. 127: 592, 1955 



9. Arden, G. B. and K. Tanslev. J. Physiol. 130: 225, 1955 



10. Armington, J. C. J. Opl. Soc. Am. 42: 393, 1952. 



11. Armington, J. C. J. Opl. Soc. Am. 45: 1058, 1955. 



12. .■\rmington, J. C., E. P. Johnson and L. A. Riggs 

 J. Physiol. 118: 289, 1952. 



13. Asher, H. J. Physiol. 112: 40P, 1951. 



14. AuERBACH, E. and H. M. Burian. Am. J. Ophlh. 40: 42 



1955- 



15. Barlow, H. B. J. Physiol. 119: 58, 1953. 



16. Barlow, H. B. J. Physiol, iig: 69, 1953. 



17. Barlow, H. B., R. Fitzhugh and S. W. Kuffler. J. 

 Physiol. 125; 28P, 1954. 



18. Benoit, p. H. and L. Cornu. Compt. raid. Soc. de biol. 



'47: 4,'54. >953- 

 ig. Bernhard, C. G. and C. R. Skoglund. Acta physiol. 



scandinau. 2: 10, 1 941. 



20. Best, W. ^Ischr. Bwl. 106: 171, 1953. 



21. Best, W. Acta ophlh. 31; 95, 1953. 



22. Bishop, P. O., D. Jeremy and J. \V. Lance. J. Physiol. 



i-!i: 415. '953- 



23. Bishop, P. O. and J. S. O'Le.arv. J. .\riirophysiol. 1 : 391, 



'938. 



24. Boll, F. .Moiialsber. Akad. W'lss. Berlin 41: 783, 1876. 



25. Bornschein, H. .Nalurwissenschaften 41 : 435, 1954. 



26. Boynton, R. M. J. Opt. Soc. Am. 43: 442, 1953. 



27. Boynton, R. M. and L. A. Riggs. J. Exper. Psychol. 42: 



217. >95i- 



28. Brindley, G. S. J. Physiol. 134; 339, 1956. 



29. Brindley, G. S. J. Physiol. 134: 353, 1956. 



30. Brindley, G. S. J. Physiol. 134: 360, 1956. 



