[Neuroscience] Re: Electrical Synapses..

jason jkrah_dot_geo_ at yahoo_dot.com
Thu Mar 2 19:03:13 EST 2006


Thanks Matthew for your response also.. Im starting to think this may be 
an area (importance of elec synapse) of debate in coming years..

The other day I read (and please remember I am really a beginner) that 
GapJuncions (ie elect synapse) can potentially also allow the transfer 
of larger molecules ie transmitters / 2nd Messenger molecules etc..
Surely this also had some huge potential for the (long term)  modulation 
of cells..

The thing I find really interesting (and complex) is the Integrative 
functions of these gap junctions.. reading about the Leech S-Cell 
network (& effects of 5ht in learning) - it seems that when a group of 
cells is tightly coupled by gap-junctions - they can be thought of 
effectively  one-big-cell.. now if massive connected area of cells exist 
(eg cortex) - can these also be considered to be acting like single 
neural entities ???

on a side note - I read about the ability of a axonal branch to delay 
and then reflect a AP back up the main axon the other day.. Im starting 
to think that in Neurobio - if soemthing is remotely physically possible 
.. then its probably happening somewhere.. I love this stuff..

Thanks again for you feedback guys!!! .. I feel priveiged to be able to 
ask these things to poeple 'in the know'..

rgds
Jason Krah


r norman wrote:
> On Mon, 27 Feb 2006 22:27:31 +1100, Matthew Kirkcaldie
> <m.kirkcaldie at removethis.unsw.edu.au> wrote:
> 
> 
>>In article <8cpnv11877uv17u7bj2118799sudpenhs4 at 4ax.com>,
>>r norman <NotMyRealEmail at _comcast.net> wrote:
>>
>>
>>>However the neglect is probably well deserved.  They do exist in both
>>>vertebrates (including humans) and invertebrates and some very special
>>>connections do use electrical synapses, but they are basically very
>>>boring.  The chemical synapses do all the "heavy lifting" in nervous
>>>calculations, because they have the ability to be much more easily
>>>modulated by a variety of causes including prior activity.  So
>>>interesting things like learning and memory must really be due to
>>>chemical synapses, not electrical ones.
>>
>>Not sure I'd concur on that front - there is an increasing body of 
>>evidence that suggests (a) inhibitory neurons in cortex are massively 
>>interconnected by electrical as well as chemical synapses, and (b) that 
>>this combination of electrical excitation and lagging chemical 
>>inhibition produces non-linear coupling, so that some types of activity 
>>and excitation get propagated through the network. It creates an 
>>environment in which particular frequencies of activity spread more 
>>easily than others, and I'm sure you would agree that has great 
>>possibilities for influencing the "interesting things"!  Especially when 
>>you consider that it seems that the favoured frequencies are in the 
>>magical "gamma band", much beloved of consciousness speculators.
>>
>>There are some good reviews by Hestrin and Galaretta I think - also some 
>>of the work has come from Peter Somogyi's lab I think.
>>
>>     Cheers, MK.
> 
> 
> Many thanks for this information.   The changes that occur during
> learning and memory may be primarily due to metabotropic chemical
> synapses but, as you say, the inMK teraction between electrical and
> chemical might well produce extremely interesting events that might
> well be an important part of the story we do not yet fully understand.
> 
> 
> 
> 


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