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Medical Neuron synapse density

  1. May 9, 2010 #1
    Does anyone know what areas of the brain have a denser amount of synapse? Are there more connections on the outside area than the inner areas, or is it uniform for the most part?
     
  2. jcsd
  3. May 9, 2010 #2

    Monique

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    Do you know the difference between grey and white brain matter?
     
  4. May 9, 2010 #3
    Im asking only within the gray matter area.
     
  5. May 9, 2010 #4
    Here is some fun: http://faculty.washington.edu/chudler/facts.html

    Beyond that, I would guess it's the neocortex/visual cortex, but I don't really remember. This isn't an issue that normally is raised outside of a loss of density due to anti-psychotic treatments, or older studies into possible signs and causes of retardation.
     
  6. May 9, 2010 #5

    apeiron

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    You might have to be more specific with what you mean by dense. Or better yet, what is the reason for asking? What do you think density signifies?

    For example, the Purkinje cells of the cerebellum have the most synapses per dendritic tree - around 200,000. But these are also long trailing fibres, so probably not dense in the way you mean.

    There is also the evidence from infant synaptic pruning and the loss of frontal gray matter with adolescent that a density of neurons/synapses is not some direct measure of how smart some part of the brain might be. A lot of connectivity can just spell naive plasticity, while a well pruned network and sparse connectivity can spell well tuned function.

    So what is it that you really want to know here?
     
  7. May 9, 2010 #6
    Not to mention that too much connectivity and activity is associated with quite a few mental illnesses. The assumption that, "stupid or crazy" means "deficient in the raw material" has been shown to be flawed for some time.
     
  8. May 10, 2010 #7
    By density I meant number of connections. Say an area on the cerebral cortex is 3 mm thick, my question is weather the outer most .1 mm part has more connections per neuron than the inner most .1 mm part of the thickness.
    Sorry for being a bit vague, this isn't really my subject, thanks.

    Edit: Found This-> http://www.mrc.uidaho.edu/~rwells/techdocs/Cortical Neurons and Circuits.pdf
     
    Last edited: May 11, 2010
  9. May 11, 2010 #8

    apeiron

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    That's a good reference, but it doesn't really answer your question on synapses (though it covers columns nicely).

    If I had to take a guess, layer 3 would seem a likely candidate for greatest synaptic density because of its higher proportion of relatively small pyramidal neurons. Layers 1 and 6 - the most outer and inner - would be more likely to be the least dense.
     
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