5 : 3/ Electrical Potentials of the Brain 



93 



temperature of a room ; (b) a method of sensing this quantity such as a 

 thermostat; and (c) an active mechanism whose rate can be varied by 

 the sensing element to effect the control (in this example, an oil furnace). 

 If the control opposes changes, the loop is said to have a negative feed- 

 back. Similar negative feedback loops are common in electronics. One 

 such frequent use is to keep an amplifier's gain constant in spite of changes 

 in supply voltages and tube characteristics. Feedback loops can also 



Pre -motor 



Suppressor 



Suppressor 



Biological 

 Intelligence 



Somato-mofor 



Somato- sensory 



-Suppressor 



Bodily 

 Awareness 



Writing 



__ Speech 

 Understanding 



Visuo-sensory 

 Visuo-psychic 



Suppressor 



Biological ^ j^ \ 

 Intelligence '• $.-'„' 



Reading 



(Visual Speech) 



Audito- / I Suppressor 



psychic Audito-sensory 



Somato -motor Somato -sensory 

 Stressor . ;; ^^ [i!; ^ ! ^^^ ^Suppressor 

 Pre -motor ~ ^^f ^ssl^ ,|!p''! ■ sUP"^*^ 



Suppressor 



Visuo-psychic 



Visuo-sensory 



Suppressor 



Olfactory 



Figure 2. Functions of the human cerebral cortex. Copy- 

 right The CIBA Collection of Medical Illustrations by Frank H. 

 Netter, M.D., Vol. 1, "The Nervous System," 1953. 



maintain the output of a power supply at a constant voltage or vary an 

 amplifier's gain to keep its output constant. The latter is illustrated 

 in Figure 3b. 



Instead of just one room, it is sometimes desired to regulate indepen- 

 dently the temperature of several rooms. Individual thermostats may 

 control dampers in the hot air lines to their respective rooms and a 

 complex system must coordinate the results of the various thermostats to 

 control the furnace. Complex, interlocking loops also occur in the 

 nervous system. 



