Production of Laminar Lesions in the 

 Cerebral Cortex by Deuteron Irradiation 



Leonard I. Malis. Jf:rzv E. RosE.f Lawrence Krugkr.} 



AND C^HARLES P. BaKER 



Mt. Sinai Hospital, Xeiv York, New York, 



Johns Hopkins University School of Medicine. Baltimore, Maryland, and 



Brookhaien National Laboratory, Upton. Xezc York 



Our interest in radiation has been aroused by the possibiHty of iitilizins: the 

 cyclotron beam for investigation of connections and functions of the cerebral 

 cortex. 



The mammalian cerebral cortex consists of an outer layer, almost devoid 

 of nerve cells, and of several inner layers, more or less densely packed with 

 radially oriented ner\e cells. This makes it appear laminated. The functional 

 sionificance of this lamination is obscure. We thought it of interest to pro- 

 duce lesions restricted to one or several layers in order to study them 

 electrophysiologicallv and histoloeicallv. 



Other workers employing hea\y. ionizing particles usually used a high 

 energy beam. With such a beam, one can irradiate with only that portion 

 of the beam path along which the loss of energy is almost uniform. The 

 terminal .sector of the beam path i with great difTerences in energy loss) is 

 arranged to lie outside the irradiated organism. With this technique, it is 

 possible to produce substantially uniform destruction along the beam path if 

 the dose is high enough. Destruction deep within the brain can be achieved 

 by multiple irradiations. The beam path for each irradiation traverses dif- 

 ferent sectors of the brain, and the intensity of each is below threshold lor 

 destruction of the tissue. All beam paths, however, are made to con\erge on 

 the target area, which thus recei\es the desired radiation dose i Anderson et 

 al, 1957a.b; Larsson ct ai, 1959: Tobias ct ai, 1954). 



In contrast to these techniques introduced by Tobias and his co-workers 

 (1954 k we ha\'e used a beam of only moderate energy which is stopped 

 entirely within the cerebral cortex. With such a beam, it is fairly simple to 



* Supported in part by a research grant from the National Institutes of Heahh and 

 by the U.S. Atomic Energy Commission. 



t Present address: Uni\-ersity of Wisconsin. Madison. Wisconsin. 



+ Present address: L'ni\ersity of Ciahfornia Medical Center. Los Angeles. California. 



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