Divisive and subtractive inhibition in a multi-compartment neuron model.

<p><b>A</b>: Voltage traces in response to excitatory inputs at varying input locations along the dendrite. Parameter values in these simulations: <i>g</i>_{<i>Syn</i>,<i>E</i>} = 3, <i>g</i>_{<i>Syn</i>,<i>I</i>} = 0, and <i>g</i>_<i>A</i> = 0. Inputs distant from the soma lead to spike initiation with millisecond-scale delay between excitatory input and spike onset. <b>B</b>: Threshold-linear relation between output firing rates in simulations of the multi-compartment model with and without inhibition for varying input location and <i>g</i>_<i>A</i> = 20. For simulations with inhibition: <i>g</i>_{<i>Syn</i>,<i>I</i>} = 1 and <i>r</i>_<i>I</i> = 50. Inhibition is subtractive for distal excitatory input (<i>cpt</i>_<i>in</i> = 6). <b>C</b>: Critical values of <i>g</i>_<i>A</i> that define boundary between subtractive and divisive inhibition in (<i>g</i>_{<i>Syn</i>,<i>E</i>}, <i>g</i>_<i>A</i>) parameter space. The boundary shifts downward as excitatory inputs are moved to more distal locations, indicating that inhibition has a subtractive effect for lower values of <i>g</i>_<i>A</i> for more distal inputs.