Neo <neo55592 at hotmail.com> wrote:
> Also, in the cerebral cortex, how common is it for a neuron in a chain
> to loop back to the 2nd neuron prior to itself? Suppose N1 -> N2 -> N3
> -> N4. Does N3 commonly connect back to N1, does N4 commonly connect
> back to N2, etc.
I doubt anyone knows the answer to that question in any detail. For any
projection, you have a back-projection. For instance, for primary sensory
areas, the number of fibers projecting from cortex back to thalamus is about
10 times the number of projections from thalamus to cortex (but the
projections back to thalamus are thin fibers).
We are pretty sure you have a closed look if you include reticulum in your
loops, but that's not part of neocortex.
Look at the article
"On the Dimensionality of Cortical Graphs "
it's an interesting read that addresses your question in a statistical
Didier A Depireux ddepi001 at umaryland.edudidier at isr.umd.edu
685 W.Baltimore Str http://neurobiology.umaryland.edu/depireux.htm
Anatomy and Neurobiology Phone: 410-706-1272 (off)
University of Maryland -1273 (lab)
Baltimore MD 21201 USA Fax: 1-410-706-2512