| Subthreshold membrane potential resonances of single neurons are known to influence the rhythmic activity of entire neuronal networks. It is therefore vital to understand how they affect spiking and to establish a quantitative relationship between the subthreshold dynamics and firing patterns generated by a neuron. We investigate differences in spike patterns of resonant and nonresonant neurons. The former exhibit subthreshold resonance and subthreshold oscillations, the latter lack both. Complex spike patterns, reflected in multipeak densities of interspike intervals (ISI), are characteristic for resonant neurons, whereas ISI densities in nonresonant neurons are monomodal. We derive several analytical approximations for the multipeak ISI distributions in neurons with subthreshold frequency preference. The approximations are based on the Wiener-Rice series for the first passage time density of a non-Markovian random process and provide accurate results for different types of dynamics, ranging from almost Markovian to strongly non-Markovian cases. We apply these theoretical results to explore spike patterns in stellate (resonant) and pyramidal (nonresonant) cells in the entorhinal cortex in rat. ISI densities observed experimentally in these cells are in excellent agreement with the analytical model predictions, which explains the mechanisms shaping the spike patterns in these cortical neurons. |
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