206 



ROBERT P. ERICKSON 



STIMULUS . 

 CONTINUUM 



B 



Receptor 



Q 



il 



_□ 



P Q R S 



Stimuli 



Fig. 1 . Afferent fiber types and patterns of neural activity. 



A. Afferent fiber-types (or receptor types). Curves 1, 2, and 3 represent 

 the responsiveness of three hypothetical afferent fiber types (or receptor types) 

 along a hypothetical stimulus continuum. P, Q, R, and S represent four stimuli 

 along this stimulus continuum. The responsiveness of a fiber type to one of 

 these stimuli is indicated by the intersection of the response curve and the 

 ordinate erected at the stimulus. 



B. Responsiveness of the three fiber types to the four stimuli in A. In each 

 of the bar graphs is shown the responsiveness of one of the fiber types to each 

 of the stimuli in A. If recordings were obtained from one of the fiber types shown 

 in A using these stimuli, one of these three " response profiles " would be 

 obtained, depending upon which fiber type was being sampled. There would be 

 as many " response profiles " as fiber types. 



C. Across-fiber patterns. In these bar graphs are shown the patterns of 

 activity across the three fiber types produced by the four stimuli in A. Each 

 stimulus produces a characteristic pattern across the three fiber types. There 

 would be as many across-fiber patterns as stimuli. 



