28 Foster, Physical Basis of Psychical Events. 



coming up into the cortex from the white matter below 

 and belonging to cells placed, it may be, in distant 

 parts. In the occipital cortex, the axons of cells in 

 the corpus geniculatum and its fellows, axons consti- 

 tuting the optic radiations, pass into this tangle and link 

 themselves with the cortical cells. These cells, as I 

 have said, are of different forms. Conspicuous among 

 them, and especially numerous in the occipital region, 

 are the " pyramidal cells," so-called from their shape, 

 that of a pyramid sending out basal dendrites from the 

 angles at the base and an extended apical dendrite 

 from its apex. So crowded and conspicuous in the 

 occipital cortex are these pyramidal cells, especially 

 of the smaller variety, that we may probably, without 

 great error, assume that these are specially concerned in 

 vision, though we are not justified in excluding from the 

 same labours the various other kinds of cells also present, 

 into the detailed features of which I need not go. 



We may assume, I say, that these pyramidal cells are 

 concerned in vision. Whatever be the exact nature of the 

 events taking place in the axons of the optic radiations, 

 these reaching the terminal divisions of those axons in the 

 cortex, affect in some way the dendrites of the cells with 

 which those divisions are linked. We may say pro- 

 visionally, that through the axons of the optic radiations 

 these pyramidal cells are thrown into activity. 



What can we say about that activity ? Let me first of 

 all insist on the fact that the axons of these cells all lead 

 away from the part of the cortex in which the cells lie to 

 some other part of the nervous system. If the apparently 

 somewhat common view to which I alluded a little while 

 back were correct, if the process of vision were such, that 

 apsychical, simply neural events propagated along the 

 lower tracts of the mechanism suddenly culminated in the 

 cortex into psychical visual sensations, we should expect 



