Information Storage in Nerve Cells 



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Fig. 19. Dissectionof rabbit brain to illustrate features of the extracallosal isolation. 

 A slab of cerebral cortex in the hemisphere opposite the ethyl chloride lesion is 

 dissected so that the cortex is separated from all subcortical connections and 

 from the surrounding intracortical regions as well. The callosal pathway remains 

 intact and is the only connection through which input is available to the dissected 

 region. For photography, the cortex was lifted to demonstrate the underlying 

 white matter but the operative procedure, of course, is done in such a way as 

 to preserve the pial circulation to the cortical slab (38). 



Fig. 20. A Weil stained cross section of the extracallosal isolation. The integrity 

 of the callosal pathway is well visualized (38). 



hemisphere. Dependent secondary discharge does occur in such a 

 preparation as do electrically evoked trans-callosal potentials, 

 indicating that the undercut region is viable and the callosal 

 pathway intact. A Weil-stained section is shown in Figure 20. 



