"r norman" <r_s_norman from _comcast.net> wrote in message
news:1icm84hv01a1ed1nfc3o06lpusjnc1hemd from 4ax.com...
> On Sat, 26 Jul 2008 09:06:58 -0500, "Fredo" <fredo from hotmail.com> wrote:
>>>I've been reading a bit about neurophysiology and neurobiology. A number
>>of
>>texts refer to backpropagation in real neurons, where the signal
>>backpropagates, though significantly attenuated, up the dendrites.
>>>>I can't seem to find out much detail on the matter, beyond the fact that
>>it
>>exists. In particular, what is the significance? The backpropagation might
>>affect gap junction-connected neurons, but it can't back-propagate through
>>synapses, can it? If it can, what's the mechanism? Surely not
>>neurotransmitter release in the dendrites...
>>>> Yes, most surely neurotransmitter release in the dendrites. There are
> an enormous number of dendro-dendritic synapses. There are an
> enormous number of "local" neurons with no axon or with very short
> axons where the local propagation of potentials does all the work.
> There are an enormous number of "microcircuits", closely interacting
> groups of synapses working as a unit within the dendritic field. There
> are reciprocal synapses : A synapses on B and B synapses back on A
> right next door. There are serial synapses: A on B and B on C, all
> in the same microciruit area.
>> G. Shepherd, "The Synaptic Organization of the Brain" is a good
> resource.
>
Okay, that makes sense, I guess. I wasn't thinking in terms of
dendrite-to-dendrite communication so much as dendrite-to-axon communication
which didn't make as much sense to me. I also wasn't aware that dendrites
could release neurotransmitters though after reading your response and doing
some quick searching, came across the text, "Dendritic Neurotransmitter
Release" edited by M. Ludwig.
I'll try to get a copy of "The Synaptic Organization of the Brain".
Thanks a ton.
