Spock's Vulcanness makes him living without a brain for a short period of time more plausible than if the brain-nappers had chosen a Human brain. His logical mind also works in their favor, though what factors they used to determine whose brain was best to take we don't know. (Wonder what a computer run by other crew members' brains would have been like?)
They could have kidnapped Spock whole and wired him into the computer, I suppose. Also, apparently the katra goes with the brain, or else Spock would have no personality without his body.
	
		
			
		
		
	
				
			They could have kidnapped Spock whole and wired him into the computer, I suppose. Also, apparently the katra goes with the brain, or else Spock would have no personality without his body.
 
				 
 
		 
 
		 
 
		 
						
					 
 
		 
 
		 
 
		

 
 
		 
 
		 
 
		
 
 
		 
 
		 
 
		 
 
		 
 
		