32: 



BRAIN MECHANISMS AND LEARNING 



bipolars, a scries ot investigations was initiated (De Robertis and Bennett, 

 1955; Palade, 1954; Palay, 1954; Palay, 1956; Palay, 1958; Robertson, 

 1956; Sjocstrand, 1954). with the purpose ot determining whether the 

 only and general characteristic ot the synapse was the presence of the 



Fig. 13 

 Dendro-soin.uic and dendro-dcndntic contacts. N, and N.. neurones of tlie 

 human common oculo-motor nucleus showing dcndro-soinatic synapses Ds. syn. 

 and dendro-dendritic synapses Dd syn. ; ax, axon which goes to form the 

 common oculo-motor nerve. These are no intercalar neurones or recurrent 

 axonic collaterals; the connections between the neurones ot this nucleus are only 

 dendro-somatic, dendro-dendritic and dcndro-somato-dendritic. 



above-mentioned microvcsiclcs. Some neurophysiologists, such as Del 

 Castillo and Katz, and more recently Ecclcs, have attempted to correlate 

 the so-called synaptic microvcsiclcs with certain physiological observations 

 (Del Castillo and Katz, 1955; Del Castillo and Katz, 1956; Fxcles, 1957): 



