IUBio

Long Term Potentiation & Memory

Millennial Dragon james.teo at chch.ox.ac.uk
Sun May 30 08:34:55 EST 1999


Been abit quiet lately so I figured I might as well try and be
controversial and bring up the topic of LTP and memory. 

As most connectionists would know, neural networks are based loosely
on the Hebb Rule which states that synaptic efficacy changes when
there is concurrent firing. The LTP discovered by Lomo & Bliss, seemed
like the ideal thing but now, all sorts of questions have been raised
about it.
For starters nowadays, LTP seems to be not synapse-specific due to
proposed retrograde messengers (arachidonic acid and nitric oxide),
and not entirely NMDA-receptor-dependent.
Also, most studies of LTP work on the hippocampus. I don't know the
details of other tissue but there have been cases of LTP spotted (and
not spotted) in other brain tissue (eg: cerebellum, amygdala). Anyone
who knows more, do fill us in on that.
Then there is the behavioural link between LTP and memory. There are
many instances of pharmacological blockade of LTP (eg: AP5
injections), and initially rats performed badly in spatial tasks (like
the water maze). But recently, there is some question on that as rats
pretrained had no such impairment. Also gene 'knock-out' mice had no
problems in functioning. What do you people make out of that?

Hopefully that's enough for a discussion.

  



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