I have been digging in the literature lately, but I haven't found a nice answer with clear cut numbers (avg +- std) to this question:

How many presynaptic inputs receives a pyramidal cell in primary visual cortex (preferably in cat)?

To be a bit more precise here I also would like to know the following details:

Number of inputs in terms of synapses as well as number of presynaptic cells

  1. Depending on the layer the postsynaptic cell resides in

  2. Depending from where the inputs originate (afferent, horizontally recurrent, vertically recurrent etc.)

  3. How many total synapses vs from how many presynaptic cells these originate, i.e. average number of synapses per pre/post cell pair

  4. Depending on distance of presynaptic cells to the postsynaptic one

  5. Depending on type of input, excitatory vs. inhibitory

I highly appreciate if you can direct me to literature listing actual numbers :-)

  • $\begingroup$ Hello! This would be a better question to ask at biology.stackexchange.com since it doesn't touch on cognition. $\endgroup$ Sep 8, 2014 at 13:48
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    $\begingroup$ In the description of the forum it says "Cognitive Sciences Stack Exchange is a question and answer site for practitioners, researchers, and students in cognitive science, psychology, neuroscience, ..." and I guess neuroscience applies here :-) $\endgroup$ Sep 8, 2014 at 20:24
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    $\begingroup$ There's no need to lawyer up, I made no proposition to close your question; but if you post it on the biology exchange as well, you'll have a larger audience (and possibly people more equipped to answer). $\endgroup$ Sep 9, 2014 at 1:42

1 Answer 1


Very detailed estimates for almost all of your points, for cat, can be found in Binzegger, T., Douglas, R. J., & Martin, K. A. C. (2004). A quantitative map of the circuit of cat primary cortex. Journal of Neuroscience, 24(39), 8441-8453.


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