C. ESTABLE 



3^9 



US to obtain a better understanding of the functional specificity of neu- 

 rones. This concept is clear so far as the afferent and ei^^erent pathways and 

 their respective centres are concerned. 



What are the functional differences and similarities existing among the 

 manifold contacts between membranes, one of which at least, is nervous? 

 Is it merely ct^nventional to consider all c»f them synaptic, or some of 



Fig. 10 

 A.xo-dendritic cross contact in cerebellum (II). This figure shows a 

 tight fascicule of parallel fibres, each of which holds an intimate 

 cross contact (A.d. syn.) with a (D.) dendrite (as shown in Fig. 9). 

 The large amount of these axons (p.f.b.) in the plexiform layer is 

 clearly evident (see also Figs. 9 and 11). 



them synaptic but not the others? Is there a factual or conceptual issue at 

 stake or is it simply a matter of words ? 



No structural characteristic (except contiguity and discontinuity) is 

 typical of synapses: 



[a) The existence of mitochondria having been rediscovered in the 

 axonal terminal pars of certain synapses (in 1897 Held haci pointed them 

 out in the cerebellar glomeruli under the name of neurosomes), the 



