|MadSci Network: Neuroscience|
At first I thought this was an easy question, and it is if you want an easy answer: thousands. No question that a neuron has thousands of synapses. But it turns out to be more complicated.
Some sources give the average number of synapses on a neuron as 1,000 to 10,000: http://facul ty.washington.edu/chudler/facts.html#neuron Others say 'tens of thousands': http://www.med.harvard.edu/publications/On_The_Brain/Volume4/Number 2/SP95In.html
Here is a good discussion of neurons and synapses by Jeff Stripling at the University of Arkansas http://comp.uark.edu/~jstripli/CogSci-JS-L1-web.pdf Dr. Striping estimates that a certain type of neuron has 20,000 to 30,000 synapses.
Part of this difference is because different animals have different nubers of neurons, and different numbers of synapses between each neuron. Another problem is that right now it is not possible to count the number of synapses on a mammalian neuron, so instead scientists make estimates. Since the scientists have to decide how to make the best estimate, this is a little harder to understand: http://marlin.li fe.utsa.edu/Tony_June1998/page.html You can think about how the number of synapses changes how the neuron works by playing around with a model of a set of neurons that synapse together. Here is one model: http://www. tiem.utk.edu/~harrell/webmodules/synapse.html
Try the links in the MadSci Library for more information on Neuroscience.