Interaction of AMPA and NMDA conductances in transducing synaptic drive into action potential output
Using computational methods, we study the interaction of two types of excitatory glutamate receptors: AMPARs and NMDARs. Although NMDARs are well-known for their role in synaptic plasticity, we show using simplified neuron models that they may also combine with AMPARs in such a way as to normalize the translation of hundreds or thousands of synaptic inputs into action potential outputs. This normalization appears to exist over at least two parameter spaces that we have studied: distance of inputs from the soma, and the membrane potential at the location of inputs. By first looking at single-synapse EPSPs, we see that these effects are emergent and become evident only with larger patterns of synaptic inputs.