Synaptic amplification by axo-shaft synapses in a pyramidal neuron model

Both the type and location of synaptic contacts can have profound functional consequences for cortical pyramidal neurons. Axo-spinous synapses integrate evoked potentials in a linear fashion and axo-shaft ones summate responses sublinearly. Using modeling and simulation, we accurately replicate such type-dependent synaptic integration and examine one of the possible underlying mechanisms. Moreover, the integrative properties of distal spines in pyramidal neurons have a distinct impact on the neuronal output. Our results demonstrate that distal axo-shaft synapses can gate nonlinear dendritic computing with higher threshold and drive somatic potential with higher gain. The implications these results have for the computational capacity of pyramidal neurons are discussed.