[Neuroscience] Re: Long-term potentiation and depression

r norman via neur-sci%40net.bio.net (by r_s_norman from _comcast.net)
Sat Jun 14 18:20:07 EST 2008


On Sat, 14 Jun 2008 16:05:09 -0700 (PDT), Bill
<connelly.bill from gmail.com> wrote:

>On Jun 15, 12:35 am, usene... from out-of-phase.de (Christian Wilms) wrote:
>> Entertained by my own EIMC <de... from mindyaown.biz> wrote:
>>
>> > Yes, when "hours" is meant to imply "a lifetime" it takes just a second
>> > for someone like me to misinterpret the minutiae of this meaning.
>>
>> I would be willing to bet against "a lifetime"  when it comes to classic
>> LTP/LTD. I think long-term "storage" will prove to be mediated by a
>> different mechanism.
>>
>> Best, Chris
>
>Well there is LTP and there is LTP like mechanisms. Nothing in the
>brain is done by LTP (100Hz for 1 sec 3 times). However strong
>depolarisation leading to NMDA receptor dependent enhancement of
>synaptic strength, I would be willing to bet that memory formation,
>and maintainance is deeply dependent on this kind of mechanisms. (Re:
>How long does LTP last, at least a year in an Adult Rat Perforant path-
>DG (Abraham WC. How long will long-term potentiation last? Philos
>Trans R Soc Lond B Biol Sci. 2003 358(1432):735-44)

Once you start a second messenger cell signaling pathway, what you
call a "different" mechanism becomes much a matter of philosophy.  If
you temporarily upregulate a synaptic receptor pathway so that the
effect lasts hours or days until protein turnover restores it to the
old value, is that a different mechanism from one that activates a
different kind of gene switch that can last forever but still uses a
number of the same intermediaries?  I would call these different.



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