Information Storage in Nerve Cells 



197 



CJ-2 -\^\^\^\^ 

 A 



R»E. 



(((( 



Tet. 



-v^v 



Post. 



S R T 



S R T 



J 



/v^ 



^A^r- 



Pre. Tet. Post. 



Fig. 7. Oscillographic tracings from a deeply anesthetized (A) and an unanes- 

 thetized (B) cat. Derivations are from implanted bipolar electrodes (R) arranged 

 as indicated in the diagram. Recording electrodes (R) are situated between the 

 stimulating electrodes (S) on one side and the tetanizing electrode pair (T) on 

 the other. Explanation in text. Calibration: 100 microvolts and 100 milliseconds. 

 Negativity at the recording electrode produces a downward deflection of the 

 beam in this and the two succeeding figures. (Chow, K. L. and Dewson, J.: 



unpublished data.) 



Short-term storage of a temporal pattern may also be demon- 

 strated in another way. Following a technique originally described 

 by Roitbak (45), Doctors K. L. Chow and James Dewson (10) 

 have used tetanization of a local cortical region to produce an 

 effect similar to that of the ''dominant focus." Three pairs of 

 implanted electrodes were arranged as shown in the diagram of 

 Figure 7 so that the stimulating pair was at one end of the array, 

 the tetanizing pair at the other end, and the recording electrodes 

 in between. 



In the deeply anesthetized animal (Fig. 7A) nine per second 

 shocks delivered before tetanization produced only a small direct 

 cortical response (DCR) arising almost immediately out of the 

 shock artifact. The nine per second stimulus was continued through- 

 out the fifty per second tetanus and into the post-tetanization 

 period. Immediately following the tetanus the response to the 

 shock was altered and could be distinguished from the DCR by 



