brain development and stimulation

Brian Scott brians at interlog.com
Sat Apr 26 20:31:48 EST 1997



Those of you in this thread might also be interested in a recent Nature 
article (sorry but I don't have the reference right now but Khun and 
Gould are two of the authors and I think it's April) which found 
that rats raised in "enriched" environments actually have an increase in 
the number of hippocampal granule neurons produced post-natally.  So not 
only are there more synapses, there are actually more neurons with which 
to make those synapses.  
  
They also found that the enriched animals performed better on the Morris 
Water Maze test of spatial learning.

I think I agree with Stephen Black's comment in a previous post that these 
seem to be more like deprivation experiments though.


Brian

Brian Scott           | "A man is rich in proportion to the number of things 
brians at interlog.com   |  which he can afford to let alone."
Dept. of Physiology   |
University of Toronto |  - Henry David Thoreau (1817-1862)

 In article 
<Pine.LNX.3.91.970426083403.4642A-100000 at Hera>,
Stephen Black <sblack at UBISHOPS.CA> wrote:
>
>
>I'll take a stab at this interesting question but without references (my
>excuse is that I'm writing from home). First, to quote in entirety the
>original post: 
>
>On 26 Apr 1997, Laura J Miller wrote:
>
>> The recent _Newsweek_ on children, "Birth to 3", had an
>> article about the effects/benefits of stimulation on
>> brain development.  Their take on it was that "short of
>> being raised in isolation, a baby will encounter enough
>> stimulation in most households to do the trick".  I've
>> seen the studies where rodents were raised in enriched (EE)
>> and nonenriched (NE) environments where they found that the EE
>> brains have many more synapses etc.  Of course,
>> the experiment utilized two extremes (deprived vs enriched), which
>> I guess contributed to the conclusion in the article (though
>> the article didn't go into the differences in the brain or
>> anything as technical-most of the "experts" were psychologists),
>> but everything I've learned about plasticity and brain 
>> development says that stimulation generates synaptic connections
>> and general brain growth.  I don't see how they can make their
>> conclusion.
>> 
>> So, what is the feeling in the neuroscience community?  Did anyone
>> else see this article?  Is an "adequate" level of stimulation
>> all that is necessary for maximal brain development during the
>> early years?  I have trouble believing that brain development
>> has such limited potential.  I think they used extremes such as
>> references to trying to develop an Einstein to make the concept
>> of stimulation seem excessive, instead of helping parents learn
>> how to best stimulate (though, still, their point was that nothing
>> extra is really necessary if they are not in a vacuum).
>> 
>> Some more of what the article said:
>> "Does any of this [back and white toys, Mozart CDs etc] really make a
>> difference?  Can you stimulate your child into becoming another Einstein? 
>> Not likely.  All of this obsessive parenting is based on the notion that a
>> baby properly stimulated will develop faster, learn languages or music
>> better 
>> and all in all be a smarter kid."
>> 
>> " There's no evidence that specific kinds of toys or environments will
>> somehow speed up skills or groom a child for the Olympics. 'You could
>> stimulate until the cow comes home and it's not going to make any 
>> difference," says David Henry Feldman, a developmental psychologist
>> at Tufts University.  'Evolution has made sure that the baby's brain
>> is going to develop certain neural pathways.'"
>> 
>> "Researchers also caution parents against expecting that they can make
>> their kids smarter.  'The fact is, it's very very hard to raise anybody's
>> IQ,' says Edward Zigler, a Yale psychologist and a founder of Head Start."
>> 
>
>I'd pretty much agree with this point of view, although as a psychologist
>who may be an "expert" but not an expert, I guess my view has already been
>discounted. However, as an involved parent, I'd like to think that all the
>enriching experiences my wife and I provided (extra attention to nutrition
>during pregnancy, lottsa reading-to, lottsa books, lottsa "good" toys,
>educational TV, exposure to two languages, teaching them to read and type
>at an early age, encouraging questions and inquiry, travel experiences,
>encouraging acceleration in school) were effective in whatever success
>they've achieved in life (jury still out on that one).  However, it's
>becoming clear that this may be merely hubris. 
>
>For one thing, as a colleague on the list Teaching in Psychology (TIPS),
>Tom Allaway at Algoma College, Ontario has recently persuasively argued,
>these "enrichment" experiments may be misinterpreted. It can be argued
>that the baseline condition is really the enriched condition, which is
>closer to the natural environment of rats. These experiments are then
>really about the effects of deprivation. Certainly we have enough
>observations on deprived children (case of Genie, the profoundly-deprived
>California child, and recent observations on Romanian orphanage children,
>for example) to confirm the results of these animal studies that
>deprivation is not good for the developing organism. 
>
>Despite this confirmation, there is always room for caution in
>extrapolating from studies on lower animals. If I recall Harlow correctly,
>while he found dramatic effects on the behaviour of severely-deprived
>monkeys, once he took steps to reduce the emotional reactions in the test
>situation, the deprived monkeys showed no cognitive deficits, unlike the
>results reported for rats (e.g. in the Hebb-Williams maze). 
>
>Finally, the results from the twin studies of Thomas Bouchard (another
>psychological "expert", unfortunately) and his colleagues at the
>University of Minnesota are starting to have an important influence in
>child development. This work on identical twins reared together and apart
>is that being raised in different families has surprising little effect on
>many developmental outcomes. For some characteristics, such as personality
>and social attitudes, there is virtually no difference whether the twins
>are reared in the same home or different. The bottom line is that, in
>Bouchard's words, most middle-class families provide an environment that
>is "plenty good enough" to allow the full expression of the child's
>genome. The only exception I can think of is that if a child shows promise
>in a particular area (music, mathematics, whatever), it can best be
>developed with a parent who takes active steps to provide the necessary
>environment and training. But on the whole, I think the evidence is
>consistent that as parents we have far less influence than we like think
>we do. 
>
>As a parent I'm disappointed, and I'd do it the same way anyway. But
>despite the hype, the case has yet to be made that the outcome for a child
>from a good middle-class family can be enhanced by special kinds of
>enrichment. 
>
>-Stephen
>
>------------------------------------------------------------------------
>Stephen Black, Ph.D.                      tel: (819) 822-9600 ext 2470
>Department of Psychology                  fax: (819) 822-9661
>Bishop's University                    e-mail: sblack at ubishops.ca
>Lennoxville, Quebec               
>J1M 1Z7                    Bishop's Department of Psychology web page at:                                                      
>Canada                        http://www.ubishops.ca/ccc/div/soc/psy                
>------------------------------------------------------------------------
>
>
>
>


-- 
Brian Scott           | "A man is rich in proportion to the number of things 
brians at interlog.com   |  which he can afford to let alone."
Dept. of Physiology   |
University of Toronto |  - Henry David Thoreau (1817-1862)



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