INTRINSIC RHYTHMS OF THE BRAIN 



291 



^. FREQUENCY 



70 8 90 



TIME IN SECONDS 



FIG. 8. A plot of the alpha frequencies in the right centroparietal and left temporoparietal regions 

 derived from the experiment represented in figure 7. Independent fluctuations of the two hemispheres 

 are far outside the error of observation and are characteristic of the subject. [From Walter (61}.] 



FIG. 9. Fluctuations in alpha frequency of another normal subject studied in the same way as 

 in figure 7, exhibiting complex alpha analysis. The resting frequency of 1 1 .6 cycles per sec. is 

 replaced by others at 12 and 10.95 cycles per sec. which alternate in dominance, but the original 

 rate is returned to at the end of the activation period. [From Walter (61).] 



