FUNCTIONAL CHANGES INDUCED BY RADIATIONS 495 



Effects on Component Parts of the Nervous System 



We will consider the performance of certain component parts of the 

 nervous system by giving attention to the functional elements in relation 

 to information processing: 



Perception (transducer organs) 

 Impulse transmission (ner\-es, axons) 

 Information storage and utilization (brain) 

 Coordination (motor organs) 



Only a small amount of work has been done (Girden, 1935) dealing 

 with the eflfects of radiation on the tissues and organs by which external 

 stimuli are transformed into action currents. The work of Bachofer (1957) 

 and others deals with the ability of receptor organs to detect ionizing radi- 

 ation. It is significant that in receptor parts of the eye an agent such as 

 radiation, which causes ionic rearrangement by displacing electrons and 

 exciting molecules, should generate an impulse that is measurable as it is 

 transmitted along nerve pathways. 



Impulse transmission itself appears to involve the movement of free elec- 

 trons. To modify this process with ionizing radiation would be somewhat com- 

 parable to affecting an electric current in a conductor. Since in a good 

 conductor there is an abundance of free electrons, it is to be expected that 

 the comparatively small additions provided by even large doses of radiation 

 would have virtually no effect. Perhaps it should not seem surprising, there- 

 fore, to learn (Gerstner, 1956; Nachmanson, 1957) that enormously large 

 doses of radiation (10,000-100,000 r are required to produce significant 

 changes in transmission abilities of nerves and axons — doses in the range 

 that produce measurable biochemical modifications. 



After impulse transmission in the information processing system comes 

 information storage and utilization — memory, concept formation, and deci- 

 sion making. Such action occurs in the brain primarily and apparently in 

 the neurons that, to a large extent, comprise the brain. How information 

 is stored and redistributed in the processes of mental function is only slightly 

 understood, but a priori analysis suggests that it is accomplished by ionic or 

 molecular rearrangements, the level of activity at which ionizing raria- 

 tion exerts a strong effect. Impressions are that storage of genetic infor- 

 mation, which is inherited and existent in all living cells, is by sequential 

 arrangements of atoms and side chains attached at particular locations along 

 protein molecules. Whether the information transmitted by nerve impulses 

 is stored by means of side chains, by passages of valence electrons from one 

 orbit to another in a low energy lattice system, or by right and left or up 

 or down orientation is little more than speculation. 



