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H. SCHIFF AND N. SCHÔNENBERGER 



dl/dt (I = light intensity, t = time) has to be increased to get a response. 

 the nearer recordings are taken to the brain. This might indicate that simple 



a 



b 



c 



Fig. 5. 



Puise code- and puise position- modulation in a RC-fiber. 

 Frequency decreases with an increase of light intensity and vice-versa (dimming fiber). 

 The pointed line represents the photocell reply. 

 Light intensities: a) 15 lux, b) \6 lux max. c) 13 lux max. 

 The recordings were intensity modulated in order to eliminate the base line 

 and lighten up only the upper part of the spikes. 



on " and " off " light changes are no longer the adéquate stimulus in higher 



centers. 



The scope of this research, of which we give here a preliminary report, is to 

 combine structural and functional results and dérive from this a model for the 

 transformation of codes in nerve centers. 



