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F. Frank LeFever flefever at ix.netcom.com
Wed Oct 28 21:55:14 EST 1998


In <717h0c$a93 at ux.cs.niu.edu> rickert at cs.niu.edu (Neil Rickert) writes:

>
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>>                    It is a strawman.
>
>Ah, yes.  In your idealogical committment to an absurd genetic
>determinism, you must find ways to berate those who are capable of
>seeing the evidence to the contrary.
>
     It seems to me that it is Rickert who attacks strawmen: the       
     interaction of genetic and environmental forces in development
     is a truism; I doubt any of the 20,000 members of the Society for 
     Neuroscience would argue otherwise, and I see nothing in the reply
     he attacks that suggests otherwise.

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>>Again and again and again in the brain, topology is preserved.
>
>Whatever that means.  Without defining your terms, this is quite
>meaningless.

     The term does not need definition for anyone familiar with the    
     literature of developmental and functional neuroanatomy of the    
     past half-century.


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>
>>>>My disagreement is with your statement that the brain is not
limited to
>>>>signal energy flowing through the sensory neurons and information
>>>>encoded in DNA. What is this other source?
>
>>>For example, the chemical constituents of the air, the food, other
>>>parts of the environment.
>
>>Any molecule from the environment that desires to get to the brain
must pass
>>the blood-brain barrier. This is not easy and is a basic
pharmacological
>>problem when attempting to get medication to the brain.
>
>This is silly.  That medication can get to the brain is already
>enough evidence.  Moreover, there it is well know that nutritional
>disorders affect brain function.
>

      Where to begin?  How to sort out the layers of confusion?        
      Well...(starting at the top of the heap): it is useful to        
      distinguish between things "reaching" the  brain and things      
      actually "signalling" the brain.  One can "reach" the brain with 
      an ice-pick, also with a spoken word; but the processes are quite
      different.

      One wonders if Rickert knows anything at all about the vast      
      literature on the blood-brain barrier, about active transport    
      mechanisms, etc.  Yes, some medications pass the blood-brain     
      barrier, many do not.  Pathology can sometimes cause "leaks" in  
      the BBB, allowing things in which are otherwise excluded; one    
      therapeutic strategy is to deliberately damage the barrier too   
      allow temporary access by a medication otherwise excluded.

       Some food constituents enter easily, osmotically, others        
       require active transport, subject to energy constraints on the  
      transport, competition for the mechanism, etc.

       In most cases, we are talking about actions on an entirely      
      different level from the signal functions mediated by the sensory
      input which is (yes) remarkably topological in its organization.

      F. Frank LeFever, Ph.D.
      New York Neuropsychology Group



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