MECHANORECEPTION 51 



inhibition. Thus, the gradual disappearance of response to displace- 

 ment and the transition from a static to a dynamic response is related 

 to the post-excitatory silencing. 



The range of accurate frequency monitoring is more than adequate 

 to keep pace with such rhythmic activity as respiratory movements. In 

 their static capacities these stretch receptors are able to provide 

 information as to the relations of one part of the body with respect to 



3^100 



Q~- 



2 



Stimulus Frequency cjs (•) 



Fig. 42. Stimulus-response relationship. Frequency of phasic stimulus 

 (solid circles) (abscissa). Velocity of stretch (open circles) (abscissa). 

 Impulse frequency (ordinate). (Redrawn from Lowenstein and 

 Finlayson, 1960.) 



another. In the dragonfly larvae, for example, the three pairs of 

 receptors are well adapted to supply information for analyses of body 

 movements. As Fig. 43 illustrates for dragonfly larvae, the oblique 

 receptor will be stretched during respiration (A) and relaxed during 

 expiration (B). In longitudinal abdominal movement, as, for example, 

 jet propulsion locomotion, the vertical and longitudinal receptors 

 will act antagonistically. 



